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Sample records for i-section steel columns

  1. Experimental research on behavior of 460 MPa high strength steel I-section columns under cyclic loading

    Science.gov (United States)

    Wang, Jiaojiao; Shi, Gang; Shi, Yongjiu

    2014-12-01

    To investigate the seismic behavior of I-section columns made of 460 MPa high strength steel (HSS), six specimens were tested under constant axial load and cyclic horizontal load. The specimens were designed with different width-to-thickness ratios and loaded under different axial load ratios. For each specimen, the failure mode was observed and hysteretic curve was measured. Comparison of different specimens on hysteretic characteristic, energy dissipation capacity and deformation capacity were further investigated. Test results showed that the degradation of bearing capacity was due to local buckling of flange and web. Under the same axial load ratio, as width-to-thickness ratio increased, the deformation area of local buckling became smaller. And also, displacement level at both peak load and failure load became smaller. In addition, the full extent of hysteretic curve, energy dissipation capacity, ultimate story drift angle decreased, and capacity degradation occurred more rapidly with the increase of width-to-thickness ratio or axial load ratio. Based on the capacity of story drift angle, limiting values which shall not be exceeded are suggested respectively for flange and web plate of 460 MPa HSS I-section columns when used in SMFs and in IMFs in the case of axial load ratio no more than 0.2. Such values should be smaller when the axial load ratio increases.

  2. 底部加强型工字形钢管混凝土柱抗震性能研究%Study on seismic behavior of bottom strengthened I-section concrete filled steel tube columns

    Institute of Scientific and Technical Information of China (English)

    惠存; 曹万林; 董宏英; 许方方

    2013-01-01

    提出了工字型截面钢管混凝土柱,同时提出了一种在柱底部区域翼缘贴焊钢板的底部加强型工字形截面钢管混凝土柱.进行了3个不同构造的工字形钢管混凝土柱模型的低周反复荷载试验,模型1为普通工字形钢管混凝土柱,模型2为工字形截面两翼缘外侧贴焊钢板的钢管混凝土柱,模型3为工字形截面两翼缘周边均贴焊钢板的钢管混凝土柱.分析了各模型的破坏特征、承载力、刚度及退化过程、延性和滞回耗能特性.给出了工字形钢管混凝土柱正截面及斜截面承载力计算公式,计算结果与实测符合较好.研究表明:所提出的底部加强型工字形钢管混凝土柱与普通工字形钢管混凝土柱相比,承载力明显提高,延性和抗震耗能能力显著提高.%The I-section concrete filled steel tube (CFST) column and the bottom strengthened I-shaped cross section CFST column, in which the column flange was welded with steel plates, were proposed. Three column models with different constructions were tested under horizontal low cyclic loading. Model 1 was a conventional I-section CFST column; model 2 was an I-section CFST column with its outer part at the bottom of flange welded with steel plates; model 3 was an I-section CFST column with its surrounding part at the bottom of flange welded with steel plates. The failure characteristics, load-bearing capacity, stiffness and degradation process, ductility and hysteretic energy dissipation capacity of the models were analyzed. The calculation formula for cross section and oblique section load-bearing capacity of bottom strengthened I-shaped cross section CFST column was given,and the results obtained from the calculation are in good agreement with those from the experiments. The study shows that the load-bearing capacity, ductility and seismic energy dissipation capacity of the bottom strengthened I-section CFST column are improved obviously compared with the

  3. 高强度钢材工字形截面轴心受压短柱局部稳定试验研究%Experimental study on local buckling of high strength steel I-section stub columns under axial compression

    Institute of Scientific and Technical Information of China (English)

    施刚; 林错错; 王元清; 石永久

    2012-01-01

    针对高强度钢材焊接工字形截面轴心受压短柱的局部稳定性能,对9个Q460C工字形截面短柱进行轴心受压试验,分析试件局部屈曲应力、极限应力随板件宽厚比的变化规律,研究翼缘、腹板嵌固系数的取值。此外,将屈曲应力、极限应力试验结果与我国、美国和欧洲钢结构设计规范的相应设计计算结果进行对比分析,研究相应规范对于高强度钢材的适用性。结果表明:翼缘的嵌固系数可取为定值1.0,腹板的嵌固系数不宜取为定值;GB 50017—2003《钢结构设计规范》中关于高强度钢材工字形截面短柱的局部屈曲应力的计算结果是不合理的;AISC 360-05规范的极限应力计算值误差较大,但偏于保守;Eurocode 3规范的极限应力计算值与试验值较为接近,但大部分计算结果较试验值偏大。为此,建议提出新的公式计算工字形截面短柱的局部屈曲应力,而对Eurocode 3规范关于工字形截面短柱的极限应力计算公式进行修正,使其能适用于Q460C高强度钢材。%Aiming at the local buckling behavior of high strength steel welded I-section columns,9 axial compression tests of Q460C I-section stub columns were conducted.Based on the test results,the relation of buckling stress and ultimate stress of specimens with different width-to-thickness ratios were studied,and the clamping coefficients of flange and web were proposed.Besides,test results were compared with the corresponding design methods in Chinese,American and European steel structures design codes,to confirm whether the design methods can be used to calculate buckling stress and ultimate stress of Q460C I-section stub columns.The research work shows that the clamping coefficient of the flange is a fixed value 1.0,but web isn't a fixed value.The buckling stress of I-section stub columns achieved by the design method in the Chinese code is unreasonable.The ultimate stress achieved by the design method

  4. 焊接加固热作用对工形截面压弯钢构件承载性能的影响%Analysis of welding heat effect on load-carrying behavior of I section steel beam-columns strengthened by welding

    Institute of Scientific and Technical Information of China (English)

    蒋立; 王元清; 戴国欣; 张天申; 石永久

    2016-01-01

    为研究焊接加固热作用及不同初始负载对工字形压弯钢柱承载性能的影响,基于考虑热影响的热结构耦合分析方法进行了热源模型热输入改进,并考虑初始几何缺陷、初始残余应力及摩擦等,完成了不同负载下焊接加固的3个工字形压弯钢柱的模拟分析。研究了焊接位移时程、腹板应力应变重分布及荷载位移关系,通过有限元分析与相应试验结果对比验证,进而获得了试验无法获得的焊接温度场、翼缘与加固板间的焊接应力应变重分布以及翼缘边缘屈服承载力等结果,并将承载力结果与规范计算结果对比,考察了现有设计方法。结果表明,焊接顺序决定焊接变形的发展过程,焊接热输入和初始负载共同决定持载焊接的位移变化范围和焊接残余变形的大小;初始负载越大,应力应变重分布往偏心受力方向发展更多,承载力越低,而初始残余应力不影响极限承载力;采用考虑热影响的有限元方法具有一定可行性和总体安全性,规范设计方法仍有可提升空间。%In order to investigate the influence of reinforcement welding heat effect and different initial load on load-carrying behavior of I section steel beam-columns,three specimens strengthened by welding while under different load were simulated.Based on the thermal-structural coupling method considering heat effect,the analysis improved thermal input of heat source model and also considered initial geometric imperfection,initial residual stress and friction.Time history of displacement during welding,web stress-strain redistribution and load-displacement relationship were discussed,and meanwhile the effectiveness of the finite element analyses (FEA ) were verified by comparing the FEA results and test results. Furthermore,welding temperature field,stress-strain redistribution between flange and strengthening plate and flange margin yield capacity

  5. Temperature of Steel Columns under Natural Fire

    Directory of Open Access Journals (Sweden)

    F. Wald

    2004-01-01

    Full Text Available Current fire design models for time-temperature development within structural elements as well as for structural behaviour are based on isolated member tests subjected to standard fire regimes, which serve as a reference heating, but do not model natural fire. Only tests on a real structure under a natural fire can evaluate future models of the temperature developments in a fire compartment, of the transfer of heat into the structure and of the overall structural behaviour under fire.To study overall structural behaviour, a research project was conducted on an eight storey steel frame building at the  Cardington Building Research Establishment laboratory on January 16, 2003. A fire compartment 11×7 m was prepared on the fourth floor. A fire load of 40 kg/m2 was applied with 100 % permanent mechanical load and 65 % of imposed load. The paper summarises the experimental programme and shows the temperature development of the gas in the fire compartment and of the fire protected columns bearing the unprotected floors.

  6. design chart procedures for polygonal concrete-filled steel columns ...

    African Journals Online (AJOL)

    ADMIN

    hexagonal and octagonal steel-concrete composite columns subjected to uniaxial bending. Comparative ... cold-formed and welded sections are generally avoided in .... selected for drawing the chart as this range utilizes comparatively less ...

  7. Class 4 stainless steel box columns in fire

    OpenAIRE

    Uppfeldt, Björn; Veljkovic, Milan, ed. lit.

    2007-01-01

    A study of stainless steel cold-rolled box columns at elevated temperatures is presented, which is a part of an on-going RFCS project "Stainless Steel in Fire". Experimental results of six, class 4, stub columns at elevated temperature, tested by Ala-Outinen (2005), were used to evaluate the FE model. The FE analysis obtained using the commercially available software, ABAQUS, shows that the critical temperature was closely predicted. Further, a parametric study was performed using the same nu...

  8. Collapse Behavior of Steel Columns as Part of Steel Frame Buildings: Experiments and Numerical Models

    OpenAIRE

    Suzuki, Yusuke; Lignos, Dimitrios

    2017-01-01

    Earthquake-induced collapse risk assessment of steel frame buildings requires the use of deterioration models that simulate instabilities that cause strength and stiffness deterioration of structural steel components. In the case of steel columns in addition to cyclic deterioration in flexural strength, such models should capture the axial load – bending interaction, the axial contraction as well as the axial strength deterioration after the formation of local buckling within the column cross...

  9. Experimental investigation of axially loaded steel fiber reinforced high strength concrete-filled steel tube columns

    Institute of Scientific and Technical Information of China (English)

    卢亦焱; 李娜; 李杉; 梁鸿骏

    2015-01-01

    An experimental study on the compressive behavior of steel fiber reinforced concrete-filled steel tube columns is presented. Specimens were tested to investigate the effects of the concrete strength, the thickness of steel tube and the steel fiber volume fraction on the ultimate strength and the ductility. The experimental results indicate that the addition of steel fibers in concrete can significantly improve the ductility and the energy dissipation capacity of the concrete-filled steel tube columns and delay the local buckling of the steel tube, but has no obvious effect on the failure mode. It has also been found that the addition of steel fibers is a more effective method than using thicker steel tube in enhancing the ductility, and more advantageous in the case of higher strength concrete. An analytical model to estimate the load capacity is proposed for steel tube columns filled with both plain concrete and steel fiber reinforced concrete. The predicted results are in good agreement with the experimental ones obtained in this work and literatures.

  10. Strengthening of Steel Columns under Load: Torsional-Flexural Buckling

    Directory of Open Access Journals (Sweden)

    Martin Vild

    2016-01-01

    Full Text Available The paper presents experimental and numerical research into the strengthening of steel columns under load using welded plates. So far, the experimental research in this field has been limited mostly to flexural buckling of columns and the preload had low effect on the column load resistance. This paper focuses on the local buckling and torsional-flexural buckling of columns. Three sets of three columns each were tested. Two sets corresponding to the base section (D and strengthened section (E were tested without preloading and were used for comparison. Columns from set (F were first preloaded to the load corresponding to the half of the load resistance of the base section (D. Then the columns were strengthened and after they cooled, they were loaded to failure. The columns strengthened under load (F had similar average resistance as the columns welded without preloading (E, meaning the preload affects even members susceptible to local buckling and torsional-flexural buckling only slightly. This is the same behaviour as of the tested columns from previous research into flexural buckling. The study includes results gained from finite element models of the problem created in ANSYS software. The results obtained from the experiments and numerical simulations were compared.

  11. Computer program simplifies selection of structural steel columns

    Science.gov (United States)

    Vissing, G. S.

    1966-01-01

    Computer program rapidly selects appropriate size steel columns and base plates for construction of multistory structures. The program produces a printed record containing the size of a section required at a particular elevation, the stress produced by the loads, and the allowable stresses for that section.

  12. Experimental research on fire resistance of circular steel tube column filled with steel-reinforced high-strength concrete

    OpenAIRE

    2014-01-01

    Circular steel tube filled with steel-reinforced high-strength concrete is a new model of composite column design.The fire resistance of this composite column was investigated experimentally.One circular steel tube column filled with steel-reinforced high-strength concrete and one circular steel tube column filled with high- strength concrete were tested under axial load and fire.The test results show that the axial deformations of both kinds of the composite columns under the same load level...

  13. Seismic Behavior of Short Concrete Columns with Prestressing Steel Wires

    Directory of Open Access Journals (Sweden)

    Deng Zong-Cai

    2014-01-01

    Full Text Available The seismic behavior of short circular reinforced concrete columns was studied by testing seven columns retrofitted with prestressing steel wire (PSW, subjected to combined constant axial compression and lateral cyclic load. The main test parameters were configuration index of PSW, prestressing level of PSW, and axial compression ratio. An analysis and discussion of the test results including failure mode, hysteresis curves, skeleton curves, ductility, and degradation of stiffness was done. The results show that the seismic performance of the retrofitted specimens could be effectively enhanced even if the axial compression ratio of columns reached 0.81. The ductility index and the energy absorption capacity of the retrofitted specimens increase with the prestressing level of PSW. The formulas for calculating shear capacity of RC short columns strengthened with PSW were proposed which may be useful for future engineering designs and researches.

  14. Behaviour of concrete filled steel tubular columns under fire

    Institute of Scientific and Technical Information of China (English)

    查晓雄; 钟善桐

    2002-01-01

    A three dimensional nonlinear FE program is used to calculate the fire resistances of concrete filledsteel tubular columns under fire. The temperature distributions in the circular section fire are decided by solvingthe Fourier Transfer Equation , and the mechanical behaviour and failure of concrete filled steel tubular columnsunder fire are thus investigated, and the effects of several parameters on the fire resistance are analysed. Theresults obtained are in good agreement with the Eurocode.

  15. Stability of axially restrained steel columns under temperature action

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The in-plane elastic buckling of a steel column under thermal loading is investigated. The column is pinned at its ends, with two linear elastic springs that model the restraint provided by adjacent members in a structural assemblage or an elastic foundation. Across a section, the temperature is assumed to be linearly distributed. Based on a nonlinear strain-displacement relationship, the energy method is used to obtain the equilibrium and buckling equations. Then the buckling of columns with three different thermal loading cases is studied. The results show that the analytical formulas can be used to evaluate the critical temperature for elastic buckling. The thermal gradient plays a positive role in improving the stability of columns. Comparing these predictions with uniform temperature distribution over cross section, it can be shown that the buckling load is seriously underestimated. It can also be found that axial restraints can significantly affect the column elastic buckling loads. The critical temperature decreases with an increase of restraint stiffness. Furthermore, the effect of axial stiffness increases when increasing the thermal gradients and decreasing the slenderness ratio of columns.

  16. Theoretical research on the shear bearing capacity of exposed steel column foot

    Science.gov (United States)

    LIU, Xijin

    2017-04-01

    This paper makes an overview on the domestic research on the steel column shear capacity in detail. On such basis, in accordance with the 4th theory of strength and the flexural vibration of straight bar, it makes theoretical analysis on the shear-bearing capacity of the steel column foot with the shear key and without the shear key respectively. It proposes the methods for calculating the shear-bearing capacity of steel column foot under two situations. It suggests that Code for Design of Steel Structures should raise the separation point of exposed steel column foot, which would reduce the construction difficulty of the exposed steel column foot, shorten the construction period, improve the construction quality and provide certain theoretical references for the design and research on the steel column foot.

  17. Behavior of reinforced concrete columns strengthened by steel jacket

    Directory of Open Access Journals (Sweden)

    Mahmoud F. Belal

    2015-08-01

    Full Text Available RC columns often need strengthening to increase their capacity to sustain the applied load. This research investigates the behavior of RC columns strengthened using steel jacket technique. Three variables were considered; shape of main strengthening system (using angles, C-sections and plates, size and number of batten plates. Behavior and failure load of the strengthened columns were experimentally investigated on seven specimens divided into two un-strengthened specimen and five strengthened ones. A finite element model was developed to study the behavior of these columns. The model was verified and tuned using the experimental results. The research demonstrated that the different strengthening schemes have a major impact on the column capacity. The size of the batten plates had significant effect on the failure load for specimens strengthened with angles, whereas the number of batten plates was more effective for specimens strengthened with C-channels. Then, by using finite element (F.E package ANSYS 12.0 [1] their behavior was investigated, analyzed and verified. Test result showed a good match between both experimental tests and F.E models.

  18. Retrofitting Of Reinforced Concrete Column by Steel Jacketing

    Directory of Open Access Journals (Sweden)

    Abhishek Jodawat

    2016-07-01

    Full Text Available Reinforced concrete structures often require strengthening to increase their capacity to sustain additional loads, due to change in use that resulted in additional live loads, deterioration of the load carrying elements, design errors, construction problems during erection, aging of structure itself or upgrading to confirm to current code requirements. These situations may require additional concrete elements or the entire concrete structure to be strengthened, repaired or retrofitted. Common methods for strengthening columns include concrete jacketing, fiber reinforced polymer (FRP jacketing and steel jacketing. All these methods have been shown to effectively increase the axial load capacity of columns. The experimental study was carried out on RC column on designed and detailed using IS 456:2000 provisions. The concrete mix design being performed after conducting numerous material test and cube test to validate expected strength as per specified grade of concrete. The trial testing conducted to estimate load at 1st crack and failure load for normal RC column with capturing displacement using dial gauges at regular load increment in UTM. The loading conditions are decided based on failure load to induce cracks in column under 85% loading of the failure one. In all fifteen specimen casted and tested with three samples for failure load estimation, three samples each for plate jacketing & angle battening system and three samples each for plate jacketing & angle battening with column preloaded to 85% of its failure load. The angle batten system proves to be better compared to full plate retrofitting in terms of load carrying capacity and enhancing confinement effect.

  19. Experimental and analytical behavior of strengthened reinforced concrete columns with steel angles and strips

    Science.gov (United States)

    Khalifa, Essam S.; Al-Tersawy, Sherif H.

    2014-06-01

    The need of strengthening reinforced concrete columns, due to loss of strength and/or stiffness, is an essential requirement due to variation of the loads and environmental conditions applied on these columns. Steel jackets around the reinforced concrete (RC) columns are usually made by means of steel plates covering all over the column surface area. For the value of engineering purposes, another technique was developed using steel angles at the corners of the RC columns connected with discrete steel strips. In this paper, an experimental program is designed to evaluate the improvement in load-carrying capacity, stiffness and ductility of strengthened RC columns, concomitant with steel angles and strips. Despite of prevailing a substantially increased loading capacity and strength a pronounced enhancement in ductility and stiffness has been reported. A need for experimental test results with low value of concrete strength to mimic the local old-age structures condition that required strengthening in local countries. Seven columns specimens are tested to evaluate the strength improvement provided by steel strengthening of columns. The method of strengthened steel angles with strips is compared with another strengthening technique. This technique includes connected and unconnected steel-casing specimens. The observed experimental results describe load-shortening curves, horizontal strains in stirrups and steel strips, as well as description of failure mode. The extra-confinement pressure, due to existence of steel cage, of the strengthened RC column can be also observed from experimental results. The code provisions that predict the load-carrying capacity of the strengthened RC composite column has a discrepancy in the results. For this reason, an analytical model is developed in this paper to compare the code limit with experimental observed results. The proposed model accounts for the composite action for concrete confinement and enhancement of the local buckling

  20. Hysteretic Behavior of Steel Column Strengthened With CFRP in Thermal Environment

    OpenAIRE

    Zhen-Guo Li

    2012-01-01

    This paper is concerned with analysis for the strengthening effect of carbon fiber-reinforced polymer (CFRP) on steel columns under cyclic lateral loading in thermal environment. Based on the finite element theory of thermo-elastic problem and steel structure stability theory, the hysteretic behavior of axial compression steel columns was studied by using Ansys software. The main variables investigated are:  cyclic lateral loading, temperature, axial compression ratio and ductility. The resul...

  1. Behavior of FRP-Confined Concrete-Filled Steel Tube Columns

    Directory of Open Access Journals (Sweden)

    Yiyan Lu

    2014-05-01

    Full Text Available This paper presents the results of an experimental study into the behavior of concrete-filled steel tube columns confined by fiber-reinforced polymer (FRP. Eleven columns were tested to investigate the effects of the FRP layer number, the thickness of the steel tube and concrete strength on their load capacity and axial deformation capacity. The experimental results indicated that the FRP wrap can effectively confine the concrete expansion and delay the local buckling of the steel tube. Both the load capacity and the axial deformation capacity of concrete-filled steel tube columns can be substantially enhanced with FRP confinement. A model is proposed to predict the load capacity of the FRP-confined concrete-filled steel tube columns. The predicted results are generally in good agreement with the experimental ones obtained in this study and in the literature.

  2. Cyclic performance of concrete-filled steel batten built-up columns

    Science.gov (United States)

    Razzaghi, M. S.; Khalkhaliha, M.; Aziminejad, A.

    2016-03-01

    Steel built-up batten columns are common types of columns in Iran and some other parts of the world. They are economic and have acceptable performance due to gravity loads. Although several researches have been conducted on the behavior of the batten columns under axial loads, there are few available articles about their seismic performance. Experience of the past earthquakes, particularly the 2003 Bam earthquake in Iran, revealed that these structural members are seismically vulnerable. Thus, investigation on seismic performance of steel batten columns due to seismic loads and providing a method for retrofitting them are important task in seismic-prone areas. This study aims to investigate the behavior of concrete-filled batten columns due to combined axial and lateral loads. To this end, nonlinear static analyses were performed using ANSYS software. Herein, the behaviors of the steel batten columns with and without concrete core were compared. The results of this study showed that concrete-filled steel batten columns, particularly those filled with high-strength concrete, may cause significant increases in energy absorption and capacity of the columns. Furthermore, concrete core may improve post-buckling behavior of steel batten columns.

  3. Stiffening of short small-size circular composite steel-concrete columns with shear connectors.

    Science.gov (United States)

    Younes, Sherif M; Ramadan, Hazem M; Mourad, Sherif A

    2016-05-01

    An experimental program was conducted to investigate the effect of shear connectors' distribution and method of load application on load-displacement relationship and behavior of thin-walled short concrete-filled steel tube (CFT) columns when subjected to axial load. The study focused on the compressive strength of the CFT columns and the efficiency of the shear stud in distribution of the load between the concrete core and steel tube. The study showed that the use of shear connectors enhanced slightly the axial capacity of CFT columns. It is also shown that shear connectors have a great effect on load distribution between the concrete and steel tubes.

  4. Behavior of partially defected R.C columns strengthened using steel jackets

    Directory of Open Access Journals (Sweden)

    Ahmed Shaban Abdel-Hay

    2015-08-01

    The main parameters studied were the type of steel jacket used and height of partial strengthened part of column. One of the tested specimens was a control specimen and the other six were partially strengthened with different types of steel jackets such as using 4 steel angles at corners connected with straps, using external ties with different spacings, and using 4 steel plates with different thicknesses welded together and connected to column by anchor bolts. Finally, the experimental results were analyzed and compared with results obtained from finite element analysis using ANSYS program.

  5. Review of design codes of concrete encased steel short columns under axial compression

    Directory of Open Access Journals (Sweden)

    K.Z. Soliman

    2013-08-01

    Full Text Available In recent years, the use of encased steel concrete columns has been increased significantly in medium-rise or high-rise buildings. The aim of the present investigation is to assess experimentally the current methods and codes for evaluating the ultimate load behavior of concrete encased steel short columns. The current state of design provisions for composite columns from the Egyptian codes ECP203-2007 and ECP-SC-LRFD-2012, as well as, American Institute of Steel Construction, AISC-LRFD-2010, American Concrete Institute, ACI-318-2008, and British Standard BS-5400-5 was reviewed. The axial capacity portion of both the encased steel section and the concrete section was also studied according to the previously mentioned codes. Ten encased steel concrete columns have been investigated experimentally to study the effect of concrete confinement and different types of encased steel sections. The measured axial capacity of the tested ten composite columns was compared with the values calculated by the above mentioned codes. It is concluded that non-negligible discrepancies exist between codes and the experimental results as the confinement effect was not considered in predicting both the strength and ductility of concrete. The confining effect was obviously influenced by the shape of the encased steel section. The tube-shaped steel section leads to better confinement than the SIB section. Among the used codes, the ECP-SC-LRFD-2012 led to the most conservative results.

  6. Hysteretic Behavior of Steel Column Strengthened With CFRP in Thermal Environment

    Directory of Open Access Journals (Sweden)

    Zhen-Guo Li

    2012-09-01

    Full Text Available This paper is concerned with analysis for the strengthening effect of carbon fiber-reinforced polymer (CFRP on steel columns under cyclic lateral loading in thermal environment. Based on the finite element theory of thermo-elastic problem and steel structure stability theory, the hysteretic behavior of axial compression steel columns was studied by using Ansys software. The main variables investigated are:  cyclic lateral loading, temperature, axial compression ratio and ductility. The results show that the CFRP wraps can improve the ultimate cyclic lateral loading and ductility of steel columns prominently in thermal environment which benefit to the anti-seismic capacity of steel structure. The effect of axial compression ratio on ultimate cyclic lateral loading is very obvious, more enhancements achieved with the axial compression ratio increased. While effect of temperature on ultimate cyclic lateral loading is not very obvious below 300℃.

  7. Fire exposed steel columns with a thermal gradient over the cross-section

    NARCIS (Netherlands)

    Ojeda, O.D.; Maljaars, J.; Abspoel, R.

    2016-01-01

    Thermal gradients often occur in fire exposed structures. This paper considers thermal gradients over the cross-section of steel columns. By means of finite element simulations, the paper demonstrates that these gradients reduce the fiexural buckling resistance of the columns. This is due to the ecc

  8. Compressive Strength Prediction of Square Concrete Columns Retrofitted with External Steel Collars

    Directory of Open Access Journals (Sweden)

    Pudjisuryadi, P.

    2013-01-01

    Full Text Available Transverse confining stress in concrete members, commonly provided by transverse reinforcement, has been recognized to enhance strength and ductility. Nowadays, the confining method has been further developed to external confinement approach. This type of confinement can be used for retrofitting existing concrete columns. Many external confining techniques have been proven to be successful in retrofitting circular columns. However, for square or rectangular columns, providing effective confining stress by external retrofitting method is not a simple task due to high stress concentration at column’s corners. This paper proposes an analytical model to predict the peak strength of square concrete columns confined by external steel collars. Comparison with the experimental results showed that the model can predict the peak strength reasonably well. However, it should be noted that relatively larger amount of steel is needed to achieve comparable column strength enhancement when it is compared with those of conve tional internally-confined columns.

  9. Seismic performance of recycled concrete-filled square steel tube columns

    Science.gov (United States)

    Chen, Zongping; Jing, Chenggui; Xu, Jinjun; Zhang, Xianggang

    2017-01-01

    An experimental study on the seismic performance of recycled concrete-filled square steel tube (RCFST) columns is carried out. Six specimens were designed and tested under constant axial compression and cyclic lateral loading. Two parameters, replacement percentage of recycled coarse aggregate (RCA) and axial compression level, were considered in the test. Based on the experimental data, the hysteretic loops, skeleton curves, ductility, energy dissipation capacity and stiffness degradation of RCFST columns were analyzed. The test results indicate that the failure modes of RCFST columns are the local buckling of the steel tube at the bottom of the columns, and the hysteretic loops are full and their shapes are similar to normal CFST columns. Furthermore, the ductility coefficient of all specimens are close to 3.0, and the equivalent viscous damping coefficient corresponding to the ultimate lateral load ranges from 0.323 to 0.360, which demonstrates that RCFST columns exhibit remarkable seismic performance.

  10. Dynamic Stability of Deep and Slender Wide-Flange Steel Columns – Full Scale Experiments

    OpenAIRE

    Elkady, Ahmed Mohamed Ahmed; Lignos, Dimitrios

    2016-01-01

    In North America, a common design practice for steel frame buildings with perimeter steel special moment frames (SMFs) is to employ deep and slender wide-flange steel columns (i.e., range of column depth, d > 16 inches). Till recently, very little was known regarding the hysteretic behavior of such members because of lack of available experimental data. This paper discusses selective findings from a full-scale testing program that was conducted at École Polytechnique Montréal with the use o...

  11. Dynamic Response of RPC-Filled Steel Tubular Columns with High Load Carrying Capacity Under Axial Impact Loading

    Institute of Scientific and Technical Information of China (English)

    TIAN Zhimin; WU Ping'an; JIA Jianwei

    2008-01-01

    Experimental investigation into impact-resistant behavior of reactive powder concrete (RPC)-filled steel tubular columns was conducted, and dynamic response of the columns under axial impact loading was studied by means of numerical simulation method.Increase coefficient of load carrying capacity and ratio of load carrying capacity between steel tube and RPC core of columns were obtained.

  12. Parametric Study of Square Concrete Filled Steel Tube Columns Subjected To Concentric Loading

    Directory of Open Access Journals (Sweden)

    Bhushan H. Patil

    2014-08-01

    Full Text Available The Concrete Filled Steel Tube (CFST member has many advantages compared with the conventional concrete structural member. This study presents on the behaviour of concrete-filled steel tube (CFST columns under axial load by changing parameters. The parameters are thickness of steel tube, Grade of concrete and length of column. The study was conducted using ANSYS 13 finite element software. All the columns are 60 X 60 mm in size. The thickness of the tube is taken as 2, 3, 4, 5 and 6 mm for thickness variation. The grades of concrete infill are M25, M30, M40, M50, M60 and M70 used for grade variation. Lengths of columns are taken as 900, 1200, 1500, 1800, 2100, and 2400 mm for length variation. Buckling load is compared with Euro code 4 (1994.

  13. Probabilistic seismic performance assessment of lap-spliced RC columns retrofitted by steel wrapping jackets

    Science.gov (United States)

    Choi, Eunsoo; Youn, Heejung; Cho, Baik-Soon

    2016-06-01

    In this study, the seismic fragility curves of two reinforced concrete (RC) columns that were lap-spliced at the bottom and retrofitted with steel wrapping jackets were generated. Their seismic performance was probabilistically assessed in comparison to that of lap-spliced or continuous reinforcement RC columns. This study used two types of steel wrapping jackets, a full jacket and a split jacket. Analytical models of the four types of columns were developed based on the experimental results of the columns using OpenSEES, which is effective in conducting nonlinear time history analyses. A suite of ten artificial ground motions, modified from recorded ground motions, was used to perform nonlinear time history analyses of the analytical models with scaling of the peak ground acceleration from 0.1 g to 1.0 g in increments of 0.1 g. The steel wrapping jackets did not increase the medians for yield (slight damage state) of the lap-spiced column and did not exceed the corresponding median of the continuous reinforcement column. However, the two steel jackets increased the medians for failure by 1.872 and 2.017 times, respectively, and exceeded the corresponding median of the continuous reinforcement column by 11.8% and 20.5%, respectively.

  14. Experimental Study on Elastic-Plastic Behavior of SRC Columns with High Strength Steel

    OpenAIRE

    2006-01-01

    The demand to use high strength and high performance material because of large span and high rise of building in recent years. As to use of high-strength steel in composite steel and reinforced concrete structures, it remains to be clarified whether the ductile behavior can be ensured, especially when the high-strength steel is used in combination with High-strength concrete. This paper describes the test results on the elasto-plastic behavior of SRC column using high strength steel, and disc...

  15. Hysteretic behavior of special shaped columns composed of steel and reinforced concrete (SRC)

    Science.gov (United States)

    Chen, Zongping; Xu, Jinjun; Xue, Jianyang

    2015-06-01

    This paper describes a series of experimental investigations on seventeen specimens of steel reinforced concrete special shaped (SRCSS) columns under low cyclic reversed loading using parallel crosshead equipment. Nine T-shaped SRC columns, four L-shaped SRC columns and four +-shaped SRC columns were tested to examine the effects of shape steel configuration, loading angle, axial compressive ratio and shear-span ratio on the behavior (strength, stiffness, energy dissipation, ductility, etc.) of SRCSS column specimens. The failure modes and hysteretic performance of all the specimens were obtained in the tests. Test results demonstrate that the shear-span ratio is the main parameter affecting the failure modes of SRCSS columns. The specimens with small shear-span ratio are prone to shear failure, and the primary failure planes in SRCSS columns are parallel to the loading direction. As a result, there is a symmetry between positive and negative loading directions in the hysteretic curves of the SRCSS columns. The majority of displacement ductility coefficients for all the specimens are over 3.0, so that the SRCSS columns demonstrate a better deformation capacity. In addition, the equivalent viscous damping coefficients of all the specimens are greater than 0.2, indicating that the seismic behavior of SRCSS columns is adequate. Finally, the superposition theory was used to calculate the limits of axial compressive ratio for the specimens, and it is found that the test axial compressive ratio is close to or smaller than the calculated axial compressive ratio limit.

  16. The experimental verification on the shear bearing capacity of exposed steel column foot

    Science.gov (United States)

    Xijin, LIU

    2017-04-01

    In terms of the shear bearing capacity of the exposed steel column foot, there are many researches both home and abroad. However, the majority of the researches are limited to the theoretical analysis sector and few of them make the experimental analysis. In accordance with the prototype of an industrial plant in Beijing, this paper designs the experimental model. The experimental model is composed of six steel structural members in two groups, with three members without shear key and three members with shear key. The paper checks the shear bearing capacity of two groups respectively under different axial forces. The experiment shows: The anchor bolt of the exposed steel column foot features relatively large shear bearing capacity which could not be neglected. The results deducted through calculation methods proposed by this paper under two situations match the experimental results in terms of the shear bearing capacity of the steel column foot. Besides, it also proposed suggestions on revising the Code for Design of Steel Structure in the aspect of setting the shear key in the steel column foot.

  17. Application of headed studs in steel fiber reinforced cementitious composite slab of steel beam-column connection

    Science.gov (United States)

    Yao, Cui; Nakashima, Masayoshi

    2012-03-01

    Steel fiber reinforced cementitous composites (SFRCC) is a promising material with high strength in both compression and tension compared with normal concrete. The ductility is also greatly improved because of 6% volume portion of straight steel fibers. A steel beam-column connection with Steel fiber reinforced cementitous composites (SFRCC) slab diaphragms is proposed to overcome the damage caused by the weld. The push-out test results suggested that the application of SFRCC promises larger shear forces transferred through headed studs allocated in a small area in the slab. Finite element models were developed to simulate the behavior of headed studs. The failure mechanism of the grouped arrangement is further discussed based on a series of parametric analysis. In the proposed connection, the SFRCC slab is designed as an exterior diaphragm to transfer the beam flange load to the column face. The headed studs are densely arranged on the beam flange to connect the SFRCC slab diaphragms and steel beams. The seismic performance and failure mechanism of the SFRCC slab diaphragm beam-column connection were investigated based on the cyclic loading test. Beam hinge mechanism was achieved at the end of the SFRCC slab diaphragm by using sufficient studs and appropriate rebars in the SFRCC slab.

  18. Modelling and experimental verification on concrete-filled steel tubular columns with L or T section

    Institute of Scientific and Technical Information of China (English)

    LU Xilin; LI Xueping; WANG Dan

    2007-01-01

    Concrete-filled steel tubular columns with L or T sections were analyzed in this paper. According to the confin- ing mechanism, the stress-strain constitutive model was put forward, and calculated results were compared with experi- mental records. After that, the hysteretic rules for the in-filled concrete were constructed, aiming at the analysis on the seis- mic behavior of composite members. The simulation analysis was performed by programming it in Fortran. The models in this paper can be applied in the program of time history analysis on tall buildings with concrete-filled steel tubular columns with L or T sections.

  19. Extension of Direct Strength Method for Slender Cold Formed Steel Column Sections with Perforations

    Directory of Open Access Journals (Sweden)

    PravinAwalkonde

    2015-04-01

    Full Text Available Revolutionary development has taken place in the design methodology of thin walled structures since the introduction of direct strength method (DSM (Dr. B Schafer 2004. DSM gives direct approach for analyzing and designing the cold formed steel sections. The effort has also been put to extend DSM for the cold formed steel sections with perforations by Dr. C D Moen(2008. Though this method gives fairly accurate results for columns with medium height, but the method is not suitable for very short and slender columns. In this paper effort has been put to suggest modification in DSM formulae for slender columns. Particular column section was modelled with finite element method with different height and thickness combinations. The same section was then analyzed by DSM in CUFSM 4.06 software. Sufficient database was created through this, and the variation in the results with DSM was incorporated in modified formula in terms of thickness and length.

  20. Effect of Concrete Age and Creep on the Behavior of Concrete-Filled Steel Tube Columns

    Directory of Open Access Journals (Sweden)

    HaiYang Wang

    2016-01-01

    Full Text Available The influence of concrete age and creep on the ultimate axial loading capacity of concrete-filled steel tube (CFST columns is experimentally and numerically investigated. After validation of numerical models, a parametric study is conducted and the results are used to formulate empirical formulas for predicting the ultimate axial load-bearing capacity of the columns. Formulas are also proposed for predicting both the composite creep and aging coefficients of the CFST columns, which consider the confinement action of steel tubes on concrete. Then, the proposed formulas are validated independently by comparing their predictions with existing test results performed by other researchers. The comparisons show that the empirical formulas have the potential to be used in the practical design of CFST columns.

  1. Seismic Behavior of concrete filled steel Tubular Built-up columns

    OpenAIRE

    Huang, Yufan

    2015-01-01

    With the advantages of CFST built-up columns, including the higher confinement in the concrete, delay of the steel local buckling, higher compressive and flexural strength, earthquake and fire resistance, rapid construction, savings in the construction costs, etc. CFST built-up columns are increasing adopted in structural members with larger load eccentricity ratio and slenderness ratio, such as stadium, industrial buildings, bridge pier and pillar, and electrical transmission tower. However,...

  2. On the performance of circular concrete-filled high strength steel columns under axial loading

    Directory of Open Access Journals (Sweden)

    Mohamed Mahmoud El-Heweity

    2012-06-01

    Full Text Available This work presents a numerical study to investigate the performance of circular high-strength steel tubes filled with concrete (CFT under monotonic axial loading. A model is developed to implement the material constitutive relationships and non-linearity. Calibration against previous experimental data shows good agreement. A parametric study is then conducted using the model and compared with codes provisions. Strength and ductility of confined concrete are of primary concern. Variables considered are yield stress of steel tube and column diameter. The assessment of column performance is based on axial load carrying capacities and enhancements of both strength and ductility due to confinement. Two parameters namely strength enhancement factor (Kf and ductility index (μ are clearly defined and introduced for assessment. Results indicate that both concrete strength and ductility of CFT columns are enhanced but to different extents. The ductile behaviors are significantly evident. The increase in yield stress of steel tube has a minimal effect on concrete strength but pronounced effect on concrete ductility. However, reduction in ductility is associated with using high-tensile steel of Grade 70. The overall findings indicate that the use of high-strength tube in CFT columns is not promising. This finding may seriously be considered in seismic design.

  3. European column buckling curves and finite element modelling including high strength steels

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Stan, Tudor-Cristian

    2017-01-01

    Eurocode allows for finite element modelling of plated steel structures, however the information in the code on how to perform the analysis or what assumptions to make is quite sparse. The present paper investigates the deterministic modelling of flexural column buckling using plane shell element...

  4. Assessment on Ultimate Load of Cold-formed Steel Channel (CFSC Stub Column

    Directory of Open Access Journals (Sweden)

    Mohd Sani Mohd Syahrul Hisyam

    2015-01-01

    Full Text Available Cold-formed steel is used as the non-structural and structural material in civil engineering work and building. Cold-formed steel channel is selected and cut into 100 mm, 200 mm, 300 mm, 400 mm and 500 mm. The slenderness ratio is calculated and noted as a stub or short column because below 40. The column is tested by using Universal Testing Machine to determine the ultimate load of the stub column. Besides, the CFSC is determined the material properties of CFSC for checking it’s the originality of steel based material. The experimental data are tested and compared with the Direct Strength Method (DSM. It showed that the CFSC1 with a height of 100 mm is reported to have a higher value of ultimate load when compared with other samples. When the height of the stub column increased, the ultimate load of the sample is decreased. Then, the CFSC1 also showed a higher in initial stiffness when compared with other samples. All samples are shown having a higher data in ultimate load when compared with the Direct Strength Method prediction. The ultimate load of experimental and DSM all gave a ratio below 1.03. Finally, all samples can further recommend determining the relation between the ultimate loads with variations of height of the column.

  5. Experimental Investigation of the Hysteretic Behavior of Wide-Flange Steel Columns under High Axial Load and Lateral Drift Demands

    OpenAIRE

    Lignos, Dimitrios; Cravero, Julien; Elkady, Ahmed Mohamed Ahmed

    2016-01-01

    This paper discusses the findings from a large-scale experimental program that characterized the hysteretic behavior of typical steel wide-flange columns in steel moment-resisting frames (MRFs). The test specimens were tested in a cantilever configuration with a fixed point of inflection. The main testing parameters included various lateral and axial loading histories, the applied axial compressive load and the local slenderness of the cross-section. It is shown that (a) steel columns subject...

  6. Finite Element Analysis and Codal Recommendations of Concrete Filled Steel Tubular Columns

    Science.gov (United States)

    Jayalekshmi, S.; Sankar Jegadesh, J. S.

    2016-03-01

    This work presents the numerical behaviour and theoretical design of axially loaded Concrete Filled Steel Tubular (CFST) columns. A numerical investigation using commercial software ANSYS is performed. The numerical models are used for the computations and the results are validated with the corresponding experimental program from the literature. It is observed that the numerical model is able to map the load deflection response of the CFST specimens. A good concurrence is also observed between the experimental and the predicted numerical results. The column strength predicted from the finite element analysis and by using the American Institute of Steel Construction and the Chinese CECS specifications are compared with the corresponding experimental results obtained from the literature. The comparative results ensured that D/t ratio plays a prominent role on the compressive behaviour of the CFST specimens. This paper quantifies the difference between the experimental and numerical results, and the ultimate load of the CFST columns estimated by various International code procedures.

  7. Packed column supercritical fluid chromatography using stainless steel particles and water as a stationary phase.

    Science.gov (United States)

    Murakami, Jillian N; Thurbide, Kevin B

    2015-09-15

    Stainless steel (SS) particles were demonstrated as a novel useful support for a water stationary phase in packed column supercritical fluid chromatography using a CO2 mobile phase. Separations employed flame ionization detection, and the system was operated over a range of temperatures and pressures. Retention times reproduced well with RSD values of 2.6% or less. Compared to analogous separations employing a water stationary phase coated onto a SS capillary column, the packed column method provided separations that were about 10× faster, with nearly 8-fold larger analyte retention factors, while maintaining good peak shape and comparable column efficiency. Under normal operating conditions, the packed column contains about 131 ± 4 μL/m of water phase (around a 5% m/m coating), which is over 25× greater than the capillary column and also affords it a 20-fold larger sample capacity. Several applications of the packed column system are examined, and the results indicate that it is a useful alternative to the capillary column mode, particularly where analyte loads or sample matrix interference is a concern. Given its high sample capacity, this packed column method may also be useful to explore on a more preparative scale in the future.

  8. Mechanical Behavior of Recycled Aggregate Concrete-Filled Steel Tubular Columns before and after Fire.

    Science.gov (United States)

    Liu, Wenchao; Cao, Wanlin; Zhang, Jianwei; Wang, Ruwei; Ren, Lele

    2017-03-09

    Recycled aggregate concrete (RAC) is an environmentally friendly building material. This paper investigates the mechanical behavior of recycled aggregate concrete filled steel tube (RACFST) columns exposed to fire. Two groups of 12 columns were designed and tested, under axial compression, before and after fire, to evaluate the degradation of bearing capacity due to fire exposure. Six specimens were subjected to axial compression tests at room temperature and the other six specimens were subjected to axial compression tests after a fire exposure. The main parameters of the specimens include the wall thickness of the steel tube (steel content) and the type of concrete materials. Several parameters as obtained from the experimental results were compared and analyzed, including the load-bearing capacity, deformation capacity, and failure characteristics of the specimens. Meanwhile, rate of loss of bearing capacity of specimens exposed to fire were calculated based on the standards EC4 and CECS28:90. The results show that concrete material has a large influence on the rate of loss of bearing capacity in the case of a relatively lower steel ratio. While steel content has little effect on the rate of loss of bearing capacity of concrete-filled steel tube (CFST) columns after fire, it has a relatively large influence on the loss rate of bearing capacity of the RACFST columns. The loss of bearing capacity of the specimens from the experiment is more serious than that from the calculation. As the calculated values are less conservative, particular attention should be given to the application of recycled aggregate concrete in actual structures.

  9. Dynamic performance of angle-steel concrete columns under low cyclic loading-I: Experimental study

    Science.gov (United States)

    Zheng, Wenzhong; Ji, Jing

    2008-03-01

    This paper describes low cyclic loading testing of nine angle-steel concrete column (ASCC) specimens. In the tests, the influence of the shear-span ratio, axial compression ratio and shear steel plate ratio on the hysteretic behavior, energy dissipation, strength degradation, stiffness degradation, skeleton curve and ductility of the ASCCs is studied. Based on the test results, some conclusions are presented. The P- Δ and sectional M — ϕ hysteretic models for the ASCCs are presented in a companion paper (Zheng and Ji, 2008).

  10. Dynamic performance of angle-steel concrete columns under low cyclic loading-I: Experimental study

    Institute of Scientific and Technical Information of China (English)

    Zheng Wenzhong; Ji Jing

    2008-01-01

    This paper describes low cyclic loading testing of nine angle-steel concrete column (ASCC) specimens. In the tests, the influence of the shear-span ratio, axial compression ratio and shear steel plate ratio on the hysteretic behavior, energy dissipation, strength degradation, stiffness degradation, skeleton curve and ductility of the ASCCs is studied. Based on the test results, some conclusions are presented. The P-Δ and sectional M-(Φ) hysteretic models for the ASCCs are presented in a companion paper (Zheng and Ji, 2008).

  11. Analysis and seismic tests of composite shear walls with CFST columns and steel plate deep beams

    Science.gov (United States)

    Dong, Hongying; Cao, Wanlin; Wu, Haipeng; Zhang, Jianwei; Xu, Fangfang

    2013-12-01

    A composite shear wall concept based on concrete filled steel tube (CFST) columns and steel plate (SP) deep beams is proposed and examined in this study. The new wall is composed of three different energy dissipation elements: CFST columns; SP deep beams; and reinforced concrete (RC) strips. The RC strips are intended to allow the core structural elements — the CFST columns and SP deep beams — to work as a single structure to consume energy. Six specimens of different configurations were tested under cyclic loading. The resulting data are analyzed herein. In addition, numerical simulations of the stress and damage processes for each specimen were carried out, and simulations were completed for a range of location and span-height ratio variations for the SP beams. The simulations show good agreement with the test results. The core structure exhibits a ductile yielding mechanism characteristic of strong column-weak beam structures, hysteretic curves are plump and the composite shear wall exhibits several seismic defense lines. The deformation of the shear wall specimens with encased CFST column and SP deep beam design appears to be closer to that of entire shear walls. Establishing optimal design parameters for the configuration of SP deep beams is pivotal to the best seismic behavior of the wall. The new composite shear wall is therefore suitable for use in the seismic design of building structures.

  12. Experimental and Theoretical Analysis of Hollow Steel Columns Strengthening by CFRP

    Directory of Open Access Journals (Sweden)

    Keykha A.H.

    2015-09-01

    Full Text Available The need for strengthening and retrofitting is well known and extensive research is progressing in this field. The reasons for strengthening and retrofitting are numerous: increased loads, changes in use, deterioration, and so on. In recent years, the use of carbon fiber reinforced polymer (CFRP for strengthening has shown to be a competitive method, both regarding structural performance, and economical aspects. Extensive research has been carried out in this field. However, most of the research has been undertaken on concrete structures and for confinement, flexural, and shear strengthening. Limited research has been carried out on steel structures strengthened with CFRP. This paper presents axially loaded steel columns strengthened for increased load. The topic is studied theoretically and through laboratory tests. The theory covers analytical methods. Carbon fiber reinforced polymers has been used to strengthen the columns. The tests have been undertaken on full scale specimens, non-strengthened for reference, partially strengthened and fully strengthened

  13. Influence of Brick Walls on the Temperature Distribution in Steel Columns in Fire

    Directory of Open Access Journals (Sweden)

    António J. P. Moura Correia

    2009-01-01

    Full Text Available This paper reports on a study of steel columns embedded in walls in fire. Several fire resistance tests were carried out at the Laboratory of Testing Materials and Structures of the University of Coimbra, in Portugal. The temperatures registered in several points of the experimental models are compared with those obtained in numerical simulations carried out with the SUPERTEMPCALC finite element program. 

  14. Composite structures of steel and concrete beams, slabs, columns, and frames for buildings

    CERN Document Server

    Johnson, R P

    2008-01-01

    This book sets out the basic principles of composite construction with reference to beams, slabs, columns and frames, and their applications to building structures. It deals with the problems likely to arise in the design of composite members in buildings, and relates basic theory to the design approach of Eurocodes 2, 3 and 4.The new edition is based for the first time on the finalised Eurocode for steel/concrete composite structures.

  15. Behavior of concrete and concrete-filled circular steel tubular stub columns at constant high temperatures

    Institute of Scientific and Technical Information of China (English)

    DING Fa-xing; YU Zhi-wu

    2006-01-01

    Based on reanalyzing test results of uniaxial compressive behavior of concrete at constant high temperatures in China,with the compressive cube strength of concrete from 20 to 80 Mpa, unified formulas for uniaxial compressive strength, elastic modulus, strain at peak uniaxial compression and mathematical expression for unaxial compressive stress-strain relations for the concrete at constant high temperatures were studied. Furthermore, the axial stress-axial strain relations between laterally confined concrete under axial compression and multiaxial stress-strain relations for steel at constant high temperatures were studied. Finally,based on continuum mechanics, the mechanics model for concentric cylinders of circular steel tube with concrete core of entire section loaded at constant high temperatures was established. Applying elasto-plastic analysis method, a FORTRAN program was developed, and the concrete-filled circular steel tubular (CFST) stub columns at constant high temperatures were analyzed. The analysis results are in agreement with the experiment ones from references.

  16. Experimental Study on Mechanical Property of Steel Reinforced Concrete L-Shaped Short Columns

    Science.gov (United States)

    Li, Zhe; Qin, Hao; Dang, Hui; Li, Hui; Zhang, Jian-Shan

    The horizontal press performance of column is deteriorated because of its special-shaped section. Moreover, because the antiseismic performance of column is worse, special-shaped column is only used in regions where seismic intensity is lower. So the main problem is to enhance the ductility and shear capacity. This test study on mechanical performance has been carried out through 14 SRCLSSC and 2 RCLSSC. The study focuses on the impacts of test axial load ratio (nt), hooped reinforcement ratio (ρv), shear span ratio (λ) and steel ratio (ρss) on the shear strength and the antiseismic performance of SRCLSSC. It can be concluded that the shear strength of SRCLSSC is increasing with the increasing of nt and ρss, but the degree of increasing is small when nt is a certainty value, and that the shear strength of SRCLSSC is decreasing with increasing of λ The shear resistance formula of L-shaped column is derived through tests, the calculated results are in correspondence with those of the tests. It also can be concluded that the hysteretic loops of the SRCLSSC are full and the hysteretic behaviors are improved; the displacement ductility is increasing with increasing of ρv and ρss, but decreasing with the increasing of nt; the degree of variety in high axial load ratio is larger than that in low axial load ratio. If steel bars are added, the shear strength and displacement ductility of SRCLSSC are increased in a large degree.

  17. Dynamic analyses of steel-reinforced super high-strength concrete columns

    Institute of Scientific and Technical Information of China (English)

    JIA Jinqing; JIANG Rui; HOU Tong; XU Shilang

    2007-01-01

    The dynamic behaviors of steel-reinforced super high-strength concrete columns under seismic loading were studied with a series of experiments. Thirteen specimens, with concrete strengths ranging from 94.9 to 105.4 Mpa and shear-span ratios of 2.75, were manufactured. The axial load ratio and the stirrup reinforcement ratio were the main experimental variables affecting the dynamic behavior of the specimens. The columns under low cyclic lateral loading mainly failed in the flexural-shear mode. Shear force- displacement hysteretic curves and skeleton curves were drawn. The coefficients of the specimens' displacement ductility were calculated. Experimental results indicate that ductility decreases while the axial load ratio increases, but it increases when the stirrup reinforcement ratio increases. The limit values of the axial load ratio and the minimum stirrup reinforcement ratio of the columns were investigated to satisfy definite ductility requirements. These values were suggested as references of engineering applications and of the amendment of the current Chinese design code of steel reinforced concrete composite structures.

  18. Combined Transverse Steel-External FRP Confinement Model for Rectangular Reinforced Concrete Columns

    Directory of Open Access Journals (Sweden)

    Ahmed Al-Rahmani

    2016-02-01

    Full Text Available Recently, the need to increase the strength of reinforced concrete members has become a subject that civil engineers are interested in tackling. Of the many proposed solutions, fiber-reinforced polymer (FRP materials have attracted attention due to their superior properties, such as high strength-to-weight ratio, high energy absorption and excellent corrosion resistance. FRP wrapping of concrete columns is done to enhance the ultimate strength due to the confinement effect, which is normally induced by steel ties. The existence of the two confinement systems changes the nature of the problem, thus necessitating specialized nonlinear analysis to obtain the column’s ultimate capacity. Existing research focused on a single confinement system. Furthermore, very limited research on rectangular sections was found in the literature. In this work, a model to estimate the combined behavior of the two systems in rectangular columns is proposed. The calculation of the effective lateral pressure is based on the Lam and Teng model and the Mander model for FRP wraps and steel ties, respectively. The model then generates stress-strain diagrams for both the concrete core and the cover. The model was developed for the analysis in extreme load events, where all possible contributions to the column’s ultimate capacity should be accounted for without any margin of safety. The model was validated against experiments, and the results obtained showed good agreement with almost all of the available experimental data.

  19. Damage assessment for seismic response of recycled concrete filled steel tube columns

    Science.gov (United States)

    Huang, Yijie; Xiao, Jianzhuang; Shen, Luming

    2016-09-01

    A model for evaluating structural damage of recycled aggregate concrete filled steel tube (RCFST) columns under seismic effects is proposed in this paper. The proposed model takes the lateral deformation and the effect of repeated cyclic loading into account. Available test results were collected and utilized to calibrate the parameters of the proposed model. A seismic test for six RCFST columns was also performed to validate the proposed damage assessment model. The main test parameters were the recycled coarse aggregate (RCA) replacement percentage and the bond-slip property. The test results indicated that the seismic performance of the RCFST member depends on the RCA contents and their damage index increases as the RCA replacement percentage increases. It is also indicated that the damage degree of RCFST changes with the variation of the RCA replacement percentage. Finally, comparisons between the RCA contents, lateral deformation ratio and damage degree were implemented. It is suggested that an improvement procedure should be implemented in order to compensate for the performance difference between the RCFST and normal concrete filled steel tubes (CFST).

  20. Thin-Walled CFST Columns for Enhancing Seismic Collapse Performance of High-Rise Steel Frames

    Directory of Open Access Journals (Sweden)

    Yongtao Bai

    2017-01-01

    Full Text Available This paper numerically studied the collapse capacity of high-rise steel moment-resisting frames (SMRFs using various width-to-thickness members subjected to successive earthquakes. It was found that the long-period component of earthquakes obviously correlates with the first-mode period of high-rises controlled by the total number of stories. A higher building tends to produce more significant component deterioration to enlarge the maximum story drift angle at lower stories. The width-to-thickness ratio of beam and column components overtly affects the collapse capacity when the plastic deformation extensively develops. The ratio of residual to maximum story drift angle is significantly sensitive to the collapse capacity of various building models. A thin-walled concrete filled steel tubular (CFST column is proposed as one efficient alternative to enhance the overall stiffness and deformation capacity of the high-rise SMRFs with fragile collapse performance. With the equivalent flexural stiffness, CFST-MRF buildings with thin-walled members demonstrate higher capacity to avoid collapse, and the greater collapse margin indicates that CFST-MRFs are a reasonable system for high-rises in seismic prone regions.

  1. 密柱钢板深梁结构抗震性能试验研究%Experimental study on seismic behavior of structure with dense columns-deep steel plate beams

    Institute of Scientific and Technical Information of China (English)

    董宏英; 张力嘉; 曹万林; 乔崎云; 刘恒超

    2015-01-01

    提出了一种内藏密柱钢板深梁混凝土组合剪力墙,密柱钢板深梁为其核心钢构.为研发高性能密柱钢板深梁结构,对4个具有不同设计参数的试件进行了低周反复荷载试验.试件的密柱分为方钢管混凝土、圆钢管混凝土、工字钢3种截面,钢板深梁分为Q235,Q345两种钢材,试件剪跨比为1.5.基于试验,分析了各试件的承载力、刚度及退化过程、延性、滞回特性、耗能、损伤与破坏过程,提出了密柱钢板深梁结构承载力计算模型,计算结果与实测结果符合较好.研究结果表明:“强密柱、弱钢板深梁”型结构可实现延性屈服机制;密柱截面用钢量相同时,采用圆钢管混凝土密柱的结构性能最好;与采用Q345钢板深梁的结构相比,采用Q235钢板深梁的结构虽承载力略小但延性更好;密柱钢板深梁结构具有良好的抗震性能和延性屈服机制.%The composite concrete shear wall embedded with dense columns-deep steel plate beams as the core structure was proposed.In order to investigate a high-performance structure with dense columns-deep steel plate beams, low cyclic loading experiments were carried out on four specimens with different design parameters.Three section styles, including concrete filled square steel tube col-umn, concrete filled circular steel tube column, and I-section steel column, were adopted for dense columns.The steel strengths of deep beams included two grades, Q235 and Q345.The shear span ratios of all the specimens were 1.5.Based on the experiments, the load-bearing capacities, stiffness and deterioration processes, ductilities, hysteretic behaviors, energy dissipations, damage and failure processes of specimens were analyzed.The load-bearing capacity calculation model was established, and the calculation results were in good agreement with the test results.The investigation results show that the structure with“strong columns

  2. Practical fire design of partially encased composite steel-concrete columns according to Eurocode 4

    Directory of Open Access Journals (Sweden)

    Sadaoui Arezki

    2014-04-01

    Full Text Available A practical method based on Campus-Massonet criteria which is developed initially to steel structures with combined compression and bending is adapted for the calculation of the buckling resistance of eccentrically loaded columns. The latter at room temperature or in fire situation is expressed by a simple formula as a function of an equivalent buckling coefficient taking into account the amount the eccentricity of the compressive applied load. The method proposed combines accuracy, efficiency and convenience obviating the need of M-N interaction diagrams and long iteration process. Otherwise, the estimation of the fire resistance for a given loading is made on the assumption based on the linearity with the level applied compressive load. It was found that the fire resistance of a column subjected to an eccentric load decreases gradually with the increase in the load level (ƞ , the slenderness ratio (λ or the amount of the eccentricity. For a fire resistance of one hour, time enough to evacuate the building of all its occupants, it recommended to use η≤ 0.5 and λ ≤45. The range of values of reinforcement cover (u suggested by Eurocode 4 leads to a better fire resistance except for u = 60 mm where there is a decline of the about 10%.

  3. Investigation of in-plane moment connections of I-beams to square concrete-filled steel tube columns under gravity loads

    Directory of Open Access Journals (Sweden)

    Abdelrahim K. Dessouki

    2015-04-01

    Full Text Available This paper focuses on experimental and analytical behavior of the ultimate moment of the connections of steel I-beams to square concrete-filled steel tube columns. External stiffeners around the columns are used at the beam flange levels. Five specimens are tested monotonically. The test parameters are the column stiffener dimensions and filling the steel tube column with concrete. Two types of failure modes are observed; beam flange failure and stiffener failure. The experimental results show that the ultimate moment of the connection is increased by increasing stiffener’s dimensions and filling the steel tube column with concrete. ANSYS finite element program is used to simulate the behavior, taking into account both geometric and material nonlinearities. Analytical results that are in fair agreement with the experimental ones are then used to discuss the influence of the main geometric parameters on the connection behavior. The parameters are the stiffener and column dimensions as well as filling the steel tube column with concrete. Different square column cross sections are chosen to cover the three classes of section classifications according to Egyptian code of practice, which are: compact, non compact or slender. The increase in the ultimate moment of the connections is based upon both column cross sections’ compactness and stiffener dimensions while the maximum advantages occur with slender columns.

  4. Evaluating a steel beam’s rigid connection to a concrete filled tubular column when submitted to dynamic load

    Directory of Open Access Journals (Sweden)

    Maritza Uribe Vallejo

    2010-05-01

    Full Text Available Using prequalified connections during the structural design stage becomes increasingly necessary when developing structural en-gineering projects which include steel elements; this is so that the steel elements’ appropriate behavior can be ensured according to the structural system and seismic demand. Unfortunately, the international entities providing this type of information (i.e. FEMA only have a limit series of prequalified connections and such series do not include rigid connections between steel beams and concrete filled tubular (CFT columns having an extended end plate, which has become a very widespread building practice in Colombia. This paper describes the most important aspects of a study at the Universidad Nacional de Colombia concerning the behavior of a steel beam rigidly connected to a CFT-column, using six physical models having different width-thickness ratio (b/t columns. ANSYS v.10 software was used for studying theoretical models (finite elements analysis for comparative analysis of cyclic test theoretical and experimental results for each specimen presented for the qualification phase. The six tested specimens’ hysteretic curves are presented. Several conclusions are drawn concerning finite element validation for this type of connection and the influence of width-thickness ratio (b/t variation and design recommendations for suitable behavior under dynamic loads when this type of connection was used.

  5. Damage analysis of CFRP-confined circular concrete-filled steel tubular columns by acoustic emission techniques

    Science.gov (United States)

    Li, Dongsheng; Chen, Zhi; Feng, Quanming; Wang, Yanlei

    2015-08-01

    Damage properties of carbon fiber-reinforced polymer (CFRP) confined circular concrete-filled steel tubular (CCFT) columns were analyzed through acoustic emission (AE) signals. AE characteristic parameters were obtained through axial compression tests. The severity of damage to CFRP-CCFT columns was estimated using the growing trend of AE accumulated energy as basis. The bearing capacity of CFRP-CCFT columns and AE accumulated energy improved as CFRP layers increased. The damage process was studied using a number of crucial AE parameters. The cracks’ mode can be differentiated through the ratio of the rise time to the waveform amplitude and through average frequency analysis. With the use of intensity signal analysis, the damage process of the CFRP-CCFT columns can be classified into three levels that represent different degrees. Based on b-value analysis, the development of the obtained cracks can be defined. Thus, identifying an initial yielding and providing early warning is possible.

  6. Evaluation of post buckling residual strength of H section steel column for both ends are fixed condition

    Energy Technology Data Exchange (ETDEWEB)

    Abebe, Daniel Yeshewawork; Choi, Jae Hyouk; Kim, Jin Hyang [Chosun Univ., Gwangju (Korea, Republic of)

    2013-01-15

    Progressive collapse is a chain reaction of failures propagating throughout a portion of a structure that is disproportionate to the original local failure. When column members are subjected to unexpected load (compression load), they will buckle it the applied load is greater than the critical load the induces buckling. The post buckling strength of the columns will decrease rapidly, but if there is enough residual strength, the members will absorb the potential energy generated by the impact load to prevent progressive collapse. Thus, it is necessary to identify the relationship of the load deformation of a column member in the progressive collapse of a structure up to final collapse. In this study, we carried out nonlinear FEM analysis and based on deflection theory, we investigated the load deformation relationship of H section steel columns when both ends were fixed.

  7. Research on the Influence of Size Effect for the mechanical Performance of GFRP tube concrete steel tube composite column under axial compression

    Science.gov (United States)

    Li, Wen; Wang, Tong; Na, Yu

    2017-08-01

    FRP tube-concrete-steel tube composite column (DSTC) was a new type of composite structures. The column consists of FRP outer tube and steel tube and concrete. Concrete was filled between FRP outer tube and steel tube. This column has the character of light and high strength and corrosion resistance. In this paper, properties of DSTC axial compression were studied in depth. The properties were studied by two groups DSTC short columns under axial compression performance experiment. The different size of DSTC short columns was importantly considered. According to results of the experiment, we can conclude that with the size of the column increases the ability of it to resist deformation drops. On the other hand, the size effect influences on properties of different concrete strength DSTC was different. The influence of size effect on high concrete strength was less than that of low concrete.

  8. A new model for analyzing nonlinear torsion behavior of concrete filled steel tube columns with rectangular section

    Science.gov (United States)

    Wang, Yuhang; Nie, Jianguo; Fan, Jiansheng

    2016-06-01

    An experimental study on concrete filled steel tube columns with rectangular section subjected to compressionflexure-torsion combined action has been carried out. The failure modes and load-deformation hysteretic relations were obtained. Based on the principles of classical material mechanics, the relations between the torsion curvature of the section and the shear strain of the fiber on the section were established. Then the strain distribution on the rectangular section of concrete filled steel tube columns subjected to torsion was analyzed. The three-dimensional refined finite element model was also built, in order to make the precision verification. The matrix forms of the relation between the torsion curvature of the section and the shear strain of the fiber on the section were derived, and introduced into the fiber beam model considering nonlinear torsion effect on the section. The comparison between test results and calculation results showed that the fiber beam model considering nonlinear torsion effect had high modeling efficiency and solution precision for predicting the torsion behavior of concrete filled steel tube columns with rectangular sections, and was suitable for analyzing the dynamic response of various structures subjected to the combined cyclic load caused by the earthquake load.

  9. Joint and column behaviour of slotted cold-formed steel studs

    DEFF Research Database (Denmark)

    Andreassen, Michael Joachim; Jönsson, Jeppe

    2015-01-01

    Slotted cold-formed steel studs are used in loadbearing external plasterboard walls. The cold-formed steel studs in these walls are supported by and joined to track sections at the top and the bottom. This paper describes the compression testing of the loadbearing studs in order to observe...... with and without web stiffeners, in order to establish the influence of these on the joint behaviour and loadbearing capacity of the slotted cold-formed steel studs....

  10. Joint and column behaviour of slotted cold-formed steel studs

    DEFF Research Database (Denmark)

    Andreassen, Michael Joachim; Jönsson, Jeppe

    2015-01-01

    Slotted cold-formed steel studs are used in load bearing external plasterboard walls. The cold-formed steel studs in these walls are supported by and joined to track profiles at the bottom and top level. In this paper the load bearing studs are tested in compression in order to observe......, and are both with and without web stiffeners to see the influence of these on the joint behaviour and load bearing capacity of the slotted coldformed steel studs....

  11. Full-Scale Cyclic Testing of Deep Slender Wide-Flange Steel Beam-Columns under Unidirectional and Bidirectional Lateral Drift Demands

    OpenAIRE

    Elkady, Ahmed Mohamed Ahmed; Lignos, Dimitrios

    2017-01-01

    Deep and slender wide-flange steel beam-columns are commonly used in steel special moment frames (SMFs) in North America. These sections provide large moment-of-inertia required to satisfy the design code’s drift limits while keeping the column steel weight at minimum. Due to their low out-of-plane moment-of-inertia and high web and flange slenderness ratios, such sections are vulnerable to local and global geometric instabilities when subjected to lateral drift demands coupled with compressi...

  12. Mechanical Behavior of Rectangular Steel-Reinforced ECC/Concrete Composite Column under Eccentric Compression

    Institute of Scientific and Technical Information of China (English)

    潘金龙; 鲁冰; 顾大伟; 夏正昊; 夏天阳

    2015-01-01

    In order to improve the seismic performance, deformation ability and ultimate load-carrying capacity of columns with rectangular cross section, engineered cementitious composite (ECC) is introduced to partially substitute concrete in the edge zone of reinforced concrete columns and form reinforced ECC/concrete composite columns. Firstly, based on the assumption of plane remaining plane and the simplified constitutive models, the calculation method of the load-carrying capacity of reinforced ECC/concrete columns is proposed. The stress and strain distribu-tions and crack propagation of the composite columns in different states of eccentric compressive loading are ana-lyzed. Then, nonlinear finite element analysis is conducted to study the mechanical performance of reinforced ECC/concrete composite columns with rectangular cross section. It is found that the simulation results are in good agreement with the theoretical results, indicating that the proposed method for calculating the load-carrying capacity of concrete/ECC composite columns is valid. Finally, based on the proposed method, the effects of ECC thickness, com-pressive strength of concrete and longitudinal reinforcement ratio on the mechanical performance of reinforced ECC/concrete composite columns are analyzed. Calculation results indicate that increasing the thickness of ECC layer or longitudinal reinforcement ratio can effectively increase the ultimate load-carrying capacity of the composite column with both small and large eccentricity, but increasing the strength of concrete can only increase the ultimate load-carrying capacity of the composite column with small eccentricity.

  13. Axial Compression Properties Nonlinear Analysis on Square Double Skin Steel Stub Short Columns Filled with Recycled Concrete

    Directory of Open Access Journals (Sweden)

    Song Bing

    2016-01-01

    Full Text Available Taking the mixing amount of diatomite calcined and vitrified micro bubbles(VMB as the main changing parameters, experiment studies the properties of the vitrified micro bubbles recycled concrete blocks; then this paper adopts the finite element software ANSYS to analyze the square double skin steel stub short columns filled with recycled concrete under axial compression. According to the vertical stress distribution, strain and bearing capacity of the steel tube and core concrete, we make a contrastive axial compression properties analysis on the different hollow ratio χ(0,0.35and the VMB content(0%,100%,130% of square double skin steel stub short columns filled with recycled concrete. The result shows that: Compressive strength of VMB recycled concrete increases with the increase of diatomite calcined content, when mixing amount of diatomite calcined is 3%,the compressive strength of 130% VMB content test specimen can reach 32.45 MPa;Because of the inner circular steel tube is setted which strengthening component buckling capacity and improving the ductility of the component, stress distribution of hollow components is more balance than solid components, and their axial displacements decrease by 5.6% compared with the solid components when they reach ultimate bearing capacity; When the hollow ratio is same, ultimate bearing capacity of 130% VMB content test specimen compared with the content is 0% only reduces by about 3.5%; When the VMB content is same, ultimate bearing capacity of hollow components compared with solid components increases by about 2.5%, which reducing weight as well as improving the anti-seismic performance.

  14. ELASTO-PLASTIC BEHAVIOR OF RC FRAMES COMPOSED OF STEEL JACKETTED RC SHORT COLUMNS AND SPANDREL WALLS

    OpenAIRE

    Nasruddin

    2012-01-01

    This experimental study is a part of the investigation on the seismic design method for Double Tubes Hybrid System (DTHS) for buildings. This structural system consists of RC core walls as the interior tube, and the exterior frames composed of RC short columns and RC spandrel walls as the exterior tube. The RC core walls are designed as the Energy Dissipation Structural Walls (EDSW), which are composed of RC coupled shear walls linked by short steel H-shaped beams as the energy dissipation de...

  15. Correlation Analysis of Seismic Yield Linear Beam-column H Type Steel Column%H型钢柱的线性梁柱抗震屈服相关性分析

    Institute of Scientific and Technical Information of China (English)

    宋良瑞

    2015-01-01

    Mainly used in steel structure design of H steel column as main materials, although to a certain extent can save steel, but steel column as an important building material, engineering in all previous larger earthquake have different scope, different degree of damage. H section steel column building materials don't columns under seismic action of axial force basic remain unchanged, H section steel column seismic performance decline phenomenon, reduce the security of the building, the impact on the development of engineering building materials performance. Therefore, H section steel column linear beam-column elements related to dynamic elastoplastic seismic yield analysis, H section steel column linear beams through strong bending moment acting on the axial plane, establish contrast column for rolling h-beam column seismic per⁃formance of reference data. Data according to the model simulation, the simulation experiments show that the H steel col⁃umn under seismic action may cause the local destruction, does not alter the elastoplastic mechanical performance of the H steel column, local constraints can effectively prevent or delay the H steel column in the elastic and plastic area.%目前钢柱结构设计中主要采用H型钢柱为主要建材,尽管在一定程度上能够节约钢材,但是钢柱作为工程的重要材料,在历次较大的地震中均有不同范围、不同程度的损坏。H型钢柱建材无法在地震作用下保持柱子的轴力不变,造成H型钢柱的弹塑性下降,降低了建筑的安全性,影响了工程建材性能的发挥。为此,提出H型钢柱的线性梁柱单元动力弹塑性与抗震屈服相关性分析,将H型钢柱的线性梁柱通过弯矩作用于切面平面内,建立对比柱以获得轧制H型钢柱抗震性能的参考数据。从而对H型钢柱的线性梁柱单元动力弹塑性与抗震屈服进行系统分析。根据模型数据进行仿真实验,仿真实验表明,建材所受

  16. SEISMIC BEHAVIOR OF STEEL RIGID FRAME WITH IMPERFECT BRACE MEMBERS

    OpenAIRE

    AFZALI, Hamid; Yamao, Toshitaka; アフザリ, ハミッド; 山尾, 敏孝

    2015-01-01

    Model of a steel rigid frame made of thin-walled box section with existence of I-section brace member with initial overall and local imperfection adopted to investigate buckling effects on steel structural behavior as it was subjected to earthquake excitation. In order to take into account of the influence of local deflections on structural response, shell elements were employed to model brace member as well as base columns. Cross sections components with relatively high amplitude of buckling...

  17. Economic research of portal frame steel structure column grid layout%门式刚架钢结构柱网布置的经济性研究

    Institute of Scientific and Technical Information of China (English)

    黄聪

    2014-01-01

    Column grid layout has a significant impact on steel consumption of portal frame light steel structure, and housing cost is directly relat-ed. Through different column grid layout and different models builded by PKPM software, this article gets the economic impact of portal frame steel structure column grid layout.%基于柱网布置对门式刚架轻型钢结构房屋的用钢量有明显的影响,和房屋造价直接相关,通过不同的柱网布置,分别用PKPM软件进行建模,得出了在门式刚架厂房设计中柱距对其经济性的影响。

  18. Applying the digital-image-correlation technique to measure the deformation of an old building’s column retrofitted with steel plate in an in situ pushover test

    Indian Academy of Sciences (India)

    Shih-Heng Tung; Ming-Hsiang Shih; Wen-Pei Sung

    2014-06-01

    An in situ pushover test is carried out on an old building of Guan-Miao elementary school in south Taiwan. Columns of this building are seismically retrofitted with steel plate. The DIC (digital-image-correlation) technique is used to measure the deformation of the retrofitted column. The result shows that the DIC technique can be successfully applied to measure the relative displacement of the column. Additionally, thismethod leads to the measurement of relative displacements formany points on the column simultaneously. Hence, the column deformation curve, rotation and curvature can be determined using interpolation method. The resulting curvaturediagram reveals that the phenomenon of plastic hinge occurs at about 2% storey drift ratio, and that the DIC technique can be applied to measure column deformation in a full scale in situ test.

  19. Design of thin-walled steel column with partially closed cross-section

    OpenAIRE

    Veljkovic, Milan, ed. lit.; JOHANSSON, Bernt

    2006-01-01

    Cold formed sections can be optimized for different purposes and they are fairly inexpensive to produce in small series. They have an inherent weakness in their small torsional stiffness, which is unfavourable for columns. The solution presented here is to make closed section by adding a thin cover plate connected with self-tapping screws. It is here called a partially closed cross-section because it is not continuously and rigidly connected. The aim of this paper is to evaluate the efficienc...

  20. Numerical Determination of Shear Strength of Steel Reinforced Concrete Column Strengthened by CFRP Sheets

    Institute of Scientific and Technical Information of China (English)

    王铁成; 余流; 王立军

    2003-01-01

    The earthquake-resistant property of reinforced concrete members depends on the interaction between reinforcing bars and surrounding concrete through bond to a large degree. In this paper a general system aimed at dealing with the failure analysis of reinforced concrete columns strengthened with carbon-fiber-reinforced plastic (CFRP) sheets including bond-slip of the anchored reinforcing bars at the foot of the columns is presented. It is based on the yield design theory with a mixed modeling of the structure, according to which the concrete material is treated as a classical two-dimensional continuum, whereas the longitudinal reinforcing bars are regarded as one-dimensional rods including bond-slip at the foot of the columns. In shear reinforced zones both the shear CFRP sheets and transverse reinforcing bars are incorporated in the analysis through a homogenization procedure and they are only in tension. The approach is then implemented numerically by means of the finite-element formulation. The numerical procedure produces accurate estimates for the loading-carrying capacity of the shear members taken as an illustrative application by correlation with the experimental results, so the proposed approach is valid.

  1. PENGARUH POROSITAS PACKING STEEL WOOL TERHADAP PRESSURE DROP DIDALAM PACKED BED COLUMN PADA DISTILASI CAMPURAN ETANOL-AMIL-ALKOHOL-AIR

    Directory of Open Access Journals (Sweden)

    Trisna Kumala Dhaniswara

    2016-08-01

    Full Text Available Inventories of petroleum fuels are increasingly depleted and will someday run out. These shortcomings can be overcome by using alternative fuels, such as ethanol. Based on this, it is necessary to research and development of ethanol as a fuel. One way is with a separation in a packed distillation column. This study aims to assess the mass transfer phenomena that occur in the process of distilling a mixture of ethanol-water-amyl alcohol packed in column. In addition, this study aims to optimize temperature and reflux to obtain the highest levels of ethanol. This research method uses packed bed distillation system with the batch process. Feed used is synthetic ethanol, water, and solvent. Solvent used were amyl alcohol. Doing distillation with heating temperature is maintained. Distillation is done in the packing of stainless steel wool. Research carried out in a batch process with a variable temperature of  79°C; 84°C; 91°C; and porosity packing 20%; 30%; 40%; 50%; 60%; 70%; 80%.

  2. Behavior of concrete-filled rectangular steel tubular columns under cyclical loading%方钢管混凝土柱滞回性能研究

    Institute of Scientific and Technical Information of China (English)

    李前; 卫建军

    2012-01-01

    以含钢率、长细比、材料强度等为主要参数,在确定钢材和核心混凝土在循环荷载作用下的应力-应变关系模型的基础上,利用有限元软件ANSYS,对方钢管混凝土柱在循环荷载作用下全过程进行了计算,以模拟地震作用下方钢管混凝土柱的实际受力性能.研究表明:方钢管混凝土柱荷载-位移滞回曲线呈比较饱满的“梭形”,没有明显的捏缩现象,达到极限荷载后,仍表现出良好的延性和后期变形能力,能够满足实际工程中大跨度、重荷载的要求,是一种良好的结构形式.%Considering the steel ratio, slenderness ratio, and the material strength as the main variable parameters, based on the determination of the stress-strain relation of the steel and core concrete under the cyclic loading, use the finite element software ANSYS to calculate the concrete-filled rectangular steel tubular columns under cyclic loading in the whole process, which simulates the mechanical properties of concrete-filled rectangular steel tubular columns in actual earthquake. Research shows that: the load versus displacement hysteretic curves of concrete-filled rectangular steel tubular columns was relatively full "spindle" .without obvious pinch phenomenon. After the limit load, model structure still showed good ductility and post-deformation. The concrete-filled rectangular steel tubular columns can meet the requirements of the real projects with large span and heavy load.

  3. Damage evaluation of fiber reinforced plastic-confined circular concrete-filled steel tubular columns under cyclic loading using the acoustic emission technique

    Science.gov (United States)

    Li, Dongsheng; Du, Fangzhu; Ou, Jinping

    2017-03-01

    Glass-fiber reinforced plastic (GFRP)-confined circular concrete-filled steel tubular (CCFT) columns comprise of concrete, steel, and GFRP and show complex failure mechanics under cyclic loading. This paper investigated the failure mechanism and damage evolution of GFRP–CCFT columns by performing uniaxial cyclic loading tests that were monitored using the acoustic emission (AE) technique. Characteristic AE parameters were obtained during the damage evolution of GFRP–CCFT columns. Based on the relationship between the loading curve and these parameters, the damage evolution of GFRP–CCFT columns was classified into three stages that represented different damage degrees. Damage evolution and failure mode were investigated by analyzing the b-value and the ratio of rise time to waveform amplitude and average frequency. The damage severity of GFRP–CCFT columns were quantitatively estimated according to the modified index of damage and NDIS-2421 damage assessment criteria corresponding to each loading step. The proposed method can explain the damage evolution and failure mechanism for GFRP–CCFT columns and provide critical warning information for composite structures.

  4. Numerical simulation of the seismic behavior of self-centering steel beam-column connections with bottom flange friction devices

    Science.gov (United States)

    Guo, Tong; Song, Lianglong; Zhang, Guodong

    2011-06-01

    A new type of steel moment resisting frame with bottom flange friction devices (BFFDs) has been developed to provide self-centering capacity and energy dissipation, and to reduce permanent deformations under earthquakes. This paper presents a numerical simulation of self-centering beam-column connections with BFFDs, in which the gap opening /closing at the beam-column interfaces is simulated by using pairs of zero-length elements with compression-only material properties, and the energy dissipation due to friction is simulated by using truss elements with specified hysteretic behavior. In particular, the effect of the friction bolt bearing against the slotted plate in the BFFDs was modeled, so that the increase in lateral force and the loss of friction force due to the bolt bearing could be taken into account. Parallel elastic-perfectly plastic gap (ElasticPPGap) materials in the Open System for Earthquake Engineering Simulation (OpenSees) were used with predefined gaps to specify the sequence that each bolt went into the bearing and the corresponding increase in bending stiffness. The MinMax material in OpenSees is used to specify the minimum and maximum values of strains of the ElasticPPGap materials. To consider the loss of friction force due to bolt bearing, a number of parallel hysteretic materials were used, and the failure of these materials in sequence simulated the gradual loss of friction force. Analysis results obtained by using the proposed numerical model are discussed and compared with the test results under cyclic loadings and the seismic loading, respectively.

  5. 钢管橡胶混凝土柱滞回性能分析%Analytical Behavior of Rubber Concrete-Filled steel Tubular Columns under Cyclic Loading

    Institute of Scientific and Technical Information of China (English)

    刘艳华; 王铁良; 刘文合; 李玉清

    2014-01-01

    采用有限元分析的方法,对钢管橡胶混凝土柱荷载-位移滞回关系曲线进行计算,并系统分析钢管截面形式和橡胶粉取代率等参数对滞回曲线骨架线、承载力退化曲线、刚度退化曲线的影响。结果表明:有限元计算结果与试验结果符合较好,钢管橡胶混凝土具有较好的滞回性能。%Waste rubber processing has become a global environment and resources problems. Crushed waste rubber into rubber powder,and added into concrete,the formed of rubber concrete used as a building material,can not only achieve the utilization of waste,but also has significance for environmental protection. The cyclic behavior of rubber concrete-filled steel tubular columns was studied in this paper. The cyclic load versus later-al displacement hysteretic curve was calculated by using finite element analysis(FEA)model to investigate the behavior of the columns. Based on the theoretical model,the influences of different column cross-section type and rubber replacing ratio on the lateral load versus lateral displacement skeleton curves,capacity reduction curves and rigidity degradation curves of rubber concrete-filled steel tubular columns were discussed. Analysis shows that the predicted cyclic responses for the composite columns are in good agreement with the test results. The rubber concrete-filled steel tu-bular columns have good dynamic behaviors. The results indicate to be used for elastico-plastic analysis of the structural system.

  6. Shaking table test study on shear walls with concrete-filled steel tube columns and embedded steel-plate%钢管混凝土边框内藏钢板剪力墙振动台试验研究

    Institute of Scientific and Technical Information of China (English)

    曹万林; 王尧鸿; 董宏英; 张建伟

    2011-01-01

    进行了4个钢板剪力墙模型的模拟地震振动台试验,其中2个模型为钢管混凝土边框钢板剪力墙,高宽比分别为1.7和3.2;2个模型为钢管混凝土边框内藏钢板剪力墙,高宽比分别为1.7和3.2.试验中输人Taft地震动,测试了各试件在不同峰值加速度下的时程地震反应和动力特性,分析了剪力墙的破坏特征.研究表明:钢管混凝土边框内藏钢板混凝土剪力墙与钢管混凝土边框钢板剪力墙相比,地震反应明显较小,抗震性能显著提高.%Four steel-plate shear walls were tested on the shaking table. Two of the walls are steel-plate shear walls with concrete-filled steel tube columns and the other two are composite shear walls with concrete-filled steel tube columns and embedded steel-plate. The ratio of height to width is 1.7 and 3.2 respectively. The Taft seismic ground motion was input in the shaking table test. Based on the experiment, dynamic characters, dynamic responses and failure modes of the four specimens in different seismic peak accelerations are contrastively analyzed. The results show that compared with the steel-plate shear walls with concrete-filled steel tube columns, shear walls with concrete-filled steel tube columns and embedded steel-plate have the following characteristics: the dynamic responses are significantly reduced, the seismic behavior is significantly improved.

  7. Experimental study on seismic behavior of steel reinforced concrete column with unsymmetrical steel cross-sections%非对称配钢钢骨混凝土柱抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    曾磊; 涂祥; 许成祥; 郑山锁; 吴园园

    2013-01-01

    为研究非对称配钢钢骨混凝土柱的抗震性能,进行了12个T形配钢、12个L形配钢的钢骨混凝土柱试件在低周往复荷载作用下的试验研究,试验参数为剪跨比、轴压比、体积配箍率以及是否配置拉结筋,对受力过程、破坏形态、滞回特性、骨架曲线、延性、耗能能力等进行了分析比较.结果表明,在恒定轴向荷载和水平低周往复荷载共同作用下,非对称配钢钢骨混凝土柱表现出较好的受力性能,破坏形态主要有弯曲破坏、剪切黏结破坏、剪切斜压破坏、剪切复合型破坏4种,各试件表现出较明显的正负滞回环不对称现象.剪跨比对破坏形态有较大影响,剪切复合型破坏主要发生在配有严重不对称的L形配钢的试件中;各试件的延性性能均随轴压比的增大而降低,在L形配钢试件中更为明显;增大配箍率对T形配钢试件的延性和承载力均有明显的提高,并能改善试件屈服后的耗能能力,有效改善混凝土的脆性性质,但对于剪跨比较小的L形配钢试件受力性能的改善并不明显;配置拉结筋能够提高各试件的承载能力,改善加载后期试件的承载力衰减和刚度退化,并明显增强了L形配钢试件的变形能力.%To study the seismic behavior of unsymmetrical steel reinforced concrete column, cyclic loading tests were carried out on 12 columns with T-shaped section steel and 12 columns with L-shaped section steel. The test parameters included shear span ratio, axial compression ratio, stirrup ratio and presence of cross tie. Mechanical process, failure mode, hysteretic characteristics, skeleton curves, ductility and energy dissipation ability were taken into comparison. The result indicates that unsymmetrical steel reinforced concrete column possesses good seismic performance under constant axial compression and cyclic horizontal load. The failure modes include bonding failure, shear-bond failure, shear

  8. Seismic performance study on steel reinforced concrete columns with distributed steel bars by contrast experiment%分散式钢棒混凝土柱抗震性能对比试验研究

    Institute of Scientific and Technical Information of China (English)

    赵松林; 彭水力; 皮音培; 周定; 任珉; 邓艳青; 王燕珺

    2012-01-01

    Steel reinforced concrete (SRC) columns have good seismic performance, which are difficult to construct on high-rise buildings. Based on the same steel contain rate of the core area, a new type SRC columns with distributed steel bars was proposed. In order to study the seismic performance of this new type of columns, experiments on two groups ( each group has three specimens) SRC columns with different material in the core area on specific axial compression ratio under low cyclic loads were carried out. Based on experimental study, the loading-displacement hysteretic curves were measured, and the behavior of energy dissipation and skeleton curves of six specimens were analyzed. It was observed from the results that SRC columns with distributed steel bars have good seismic performance.%钢骨混凝土柱具有良好的抗震性能,但其在高层建筑结构中施工复杂,为此,基于核心区钢骨含钢量相同的原则提出了新型分散式钢棒混凝土柱。为研究分散式钢棒混凝土柱的抗震性能,对2组各3个不同核心材料钢骨混凝土柱在指定试验轴压比下进行了水平低周反复荷载试验。通过试验得到的荷载-位移曲线,对比分析了不同核心材料的钢骨混凝土柱耗能和骨架曲线的差异。初步试验结果表明分散式钢棒核心钢骨混凝土柱的抗震性能良好。

  9. Automated Composite Column Wrapping

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    The Automated Composite Column Wrapping is performed by a patented machine known as Robo-Wrapper. Currently there are three versions of the machine available for bridge retrofit work depending on the size of the columns being wrapped. Composite column retrofit jacket systems can be structurally just as effective as conventional steel jacketing in improving the seismic response characteristics of substandard reinforced concrete columns.

  10. Seismic Research and Application on Embedded Steel Plate Concrete Shear Wall with Concrete Filled Steel Tube Columns%钢管混凝土边框内藏钢板组合剪力墙抗震研究

    Institute of Scientific and Technical Information of China (English)

    曹万林; 张文江; 张建伟; 董宏英; 王立长

    2011-01-01

    提出了钢管混凝士边框内藏钢板组合剪力墙.完成了 12个不同构造的钢板组合剪力墙模型的低周反复荷载试验,其中包括5个钢管混凝土边框纯钢板剪力墙、7个钢管混凝土边框内藏钢板剪力墙.分析了各试件的承载力、耗能、延性、滞回特征等.给出了部分组合剪力墙的承载力计算模型,计算结果与试验结果符合较好.研究表明,钢管混凝土边框内藏钢板组合剪力墙具有承载力高、延性好、耗能能力强、滞回性能稳定等特点.这种新型组合剪力墙已用于工程,效果良好.%The embedded steel plate concrete shear wall with concrete filled steel tube columns was proposed. The tests of 12 shear wall specimens under cyclic loading have been accomplished, including 5 specimens of pure steel plate shear wall with concrete filled steel tube columns and 7 specimens of embedded steel plate concrete shear wall with concrete filled steel tube columns. The performances of specimens such as load-bearing capacity, energy dissipation, ductility and hysteretic behavior have been investigated. Formulas for load-bearing capacity of some specimens are put forward and the calculation results agree well with the experimental ones. It is shown that the embedded steel plate concrete shear wall with concrete filled steel tube columns has excellent aseismic features of higher capacity, better ductility, larger energy dissipation and more stable hysteretic behavior. This new kind of composite shear wall has been applied to the actual projects and the received response is satisfactory.

  11. Rational design method for mixed structure with steel beams and reinforced concrete column. Part 1. Experimental study on beam-column joint; Hashira RC hari S kongo kozo no goriteki sekkeiho ni kansuru kenkyu. 1. Hari kantsu keishiki no setsugobu jikken

    Energy Technology Data Exchange (ETDEWEB)

    Takami, S.; Masuda, Y.; Yoshioka, K. [Obayashi Corp., Tokyo (Japan)

    1995-08-10

    Mixed structural systems of steel beams and a reinforced concrete column have been used in practical application. Several joint types have been developed, one of which is the standard steel beams passing through a reinforced concrete column. Local compressive failure (bearing failure) often occurs in this type of joint. A loading test was carried out on a beam-column joint to develop methods for reinforcing the bending strength of columns. The results are summarized as follows; (1) Bearing behavior can be improved by constructing Pre-Columns. (2) Maximum load can be increased and ductility can be improved by covering the top and bottom of columns with steel plates. 2 refs., 6 figs., 4 tabs.

  12. Reading Columns

    OpenAIRE

    Coutts, Marion

    2008-01-01

    Reading Columns are twin permanent public sculptures commissioned as part of a £245m scheme for the redevelopment of the Chatham Place area in Reading. Dimensions: 3.5m high x 1.3m diameter each Field of knowledge: The work consists of twin bespoke columns of stainless steel and glass over digital colour transparencies. The piece revisits and reworks the idea of the Morris Column, a 19th C feature characteristic of major European metropolitan centres. A wraparound image on each of ...

  13. Scale-up protein separation on stainless steel wide bore toroidal columns in the type-J counter-current chromatography.

    Science.gov (United States)

    Guan, Yue Hugh; Hewitson, Peter; van den Heuvel, Remco N A M; Zhao, Yan; Siebers, Rick P G; Zhuang, Ying-Ping; Sutherland, Ian

    2015-12-11

    Manufacturing high-value added biotech biopharmaceutical products (e.g. therapeutic proteins) requires quick-to-develop, GMP-compliant, easy-to-scale and cost effective preparatory chromatography technologies. In this work, we describe the construction and testing of a set of 5-mm inner diameter stainless steel toroidal columns for use on commercially available preparatory scale synchronous J-type counter-current chromatography (CCC) machinery. We used a 20.2m long column with an aqueous two-phase system containing 14% (w/w) PEG1000 and 14% (w/w) potassium phosphate at pH 7, and tested a sample loading of 5% column volume and a mobile phase flow rate of 20ml/min. We then satisfactorily demonstrated the potential for a weekly protein separation and preparation throughput of ca. 11g based on a normal weekly routine for separating a pair of model proteins by making five stacked injections on a single portion of stationary phase with no stripping. Compared to our previous 1.6mm bore PTFE toroidal column, the present columns enlarged the nominal column processing throughput by nearly 10. For an ideal model protein injection modality, we observed a scaling up factor of at least 21. The 2 scales of protein separation and purification steps were realized on the same commercial CCC device.

  14. Experimental Analysis on Seismic Performance of Steel Bracing Bound-Column Component%钢支撑束柱抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    陆烨; 刘青; 李国强; 刘玉姝

    2014-01-01

    通过试验和有限元理论对比研究了钢支撑束柱的抗震性能和破坏特性。试验模型采用2层钢支撑束柱构件,其中钢支撑为长肢相并的双角钢支撑。试验共分为3组,1组为单调加载试验,另外2组为滞回性能试验。另对钢支撑束柱的抗震性能进行了有限元理论分析,经试验结果验证,得到了钢支撑束柱试件的抗侧承载力、刚度及滞回性能。研究表明,钢支撑束柱的承载力、刚度主要来自钢支撑,而束柱外框架部分的贡献很小。钢支撑束柱的破坏只发生在钢支撑中,外框架部分没有任何损坏。%The seismic resistant performance and failure mechanism of the steel bracing Bound-Column were analyzed with tests and the finite element method .Two-story steel bracing Bound-Column test specimen was selected .The braces adopt long leg back-back double angle .Tests were divided into three groups , including one monotonic loading test and two cyclic tests . Lateral load-bearing capacity , stiffness and hysteretic behavior of the steel bracing Bound-Column were obtained by the comparison of test results and the finite element method .Results show that the steel brace of Bound-Column contributes a lot to its load capacity and stiffness ,while the external frame provides little lateral rigidity and capacity .Bound-Column failure occurs only in the steel braces ,while the external frame is with no damage .

  15. DETERMINATION OF STEEL BAR PERFORATING HOLE ON RIGID REINFORCED CONCRETE BEAM AND COLUMN%劲性钢筋混凝土梁柱穿筋孔的确定

    Institute of Scientific and Technical Information of China (English)

    李小勇; 张辉; 王少松; 郭富强; 吴显辉

    2012-01-01

    Mutual obstruction of steel bar, hooked steel bar anchorage and perforation on steel skeleton are seldom considered during design of steel bar for rigid reinforced concrete. An engineering project is taken for example to make suggestions for determination of diameter of steel bar perforating hole, position of steel column hooped reinforcement hole, position of beam reinforcement hole of steel column, position of hooped reinforcement hole and draw hook hole of steel beam and position of longitudinal column reinforcement hole of steel beam.%在劲性钢筋混凝土配筋设计时较少考虑交叉梁的钢筋冲突、钢筋弯钩锚固及钢骨开孔.以具体工程为例,对穿筋孔直径的确定,钢柱箍筋孔位置确定,钢柱的梁筋孔位置确定,钢梁箍筋孔、拉钩孔位置确定,钢梁的柱纵筋孔位置确定提出了建议.

  16. Research of Design and Application of Girdling-Column Steel Beam%钢结构抱柱梁的设计与应用研究

    Institute of Scientific and Technical Information of China (English)

    吉伯海; 徐声亮; 袁爱民; 周超; 郑宏

    2011-01-01

    针对目前在桥梁整体同步顶升改造中普遍使用的混凝土抱柱梁施工周期长、墩柱界面连接强度弱、环境不友好、适用范围受限等不足,提出一种新型钢结构抱柱梁.钢结构抱柱梁采用可预制拼装的分离式钢结构,通过设置剪力键与双向预应力提高墩梁界面的承载力,并在抱柱梁承受集中力区域及应力集中部位设置加劲肋.结合浙江省某航道桥的整体顶升改造,对钢结构抱柱梁的结构布置及受力性能进行分析,并与相应的混凝土抱柱梁进行对比.分析结果表明,钢结构抱柱梁各部分受力均满足规范要求,与混凝土抱柱梁相比,钢结构抱柱梁高宽比较小、墩梁接触界面连接力大、结构可循环使用、施工效率大大提高.%Seeing the deficiency that the construction time schedule of the girdling-column (pier column) concrete beam extensively used for the current bridge retrofitting of integral and synchronous jack-up is long, the strength of connection between the column and the beam is week, the utilization of the beam is environment-unfriendly and is limited as well, a new type of the girdling-column steel beam is brought forward. The steel beam is a separated steel structure that can be prefabricated and preassembled, the bearing capacity at the interface between the column and the beam can be enhanced via setting of the shear studs and two-way prestressing tendons and the stiffeners can be set in the area of the beam which will sustain concentrated force or in the part of the beam of stress concentration. With reference to the retrofitting of integral and synchronous jacking-up for a shipping channel bridge in Zhejiang Province, the structural layout and force conditions of the girdling-column steel beam are analyzed and are compared to those of a corresponding concrete beam. The results of the analysis indicate that the force conditions of various parts of the steel beam can satisfy the relevant

  17. Ultimate tensile strength of embedded I-sections: a comparison of experimental and numerical results

    Science.gov (United States)

    Heristchian, Mahmoud; Pourakbar, Pouyan; Imeni, Saeed; Ramezani, M. Reza Adib

    2014-12-01

    Exposed baseplates together with anchor bolts are the customary method of connection of steel structures to the concrete footings. Post-Kobe studies revealed that the embedded column bases respond better to the earthquake uplift forces. The embedded column bases also, offer higher freedom in achieving the required strength, rigidity and ductility. The paper presents the results of the pullout failure of three embedded IPE140 sections, tested under different conditions. The numerical models are then, generated in Abaqus 6.10-1 software. It is concluded that, the steel profiles could be directly anchored in concrete without using anchor bolts as practiced in the exposed conventional column bases. Such embedded column bases can develop the required resistance against pullout forces at lower constructional costs.

  18. 钢梁与钢骨柱框架在大跨度屋面结构上的应用%Application of steel beam and steel reinforced concrete column frame in long-span roof structure

    Institute of Scientific and Technical Information of China (English)

    陈兴雷

    2015-01-01

    以某中学食堂、风雨操场项目为例,通过对整个建筑结构设计要求的分析,采用了钢梁与钢骨柱框架结构的方法,实践表明采用该方法解决了结构受力的难题,同时经济美观。%Taking a middle school cafeteria,gymnasium project as an example,through the analysis on overall building structure design require-ments,adopted the method combining with the steel beam and steel reinforced concrete column frame structure,the practice showed that using this method solved the problem of structure stress,at the same time,economic and beautiful.

  19. Research on fire-resistant bearing capacity of steel column with wall board in fire%火灾下带墙板钢柱抗火承载力的研究

    Institute of Scientific and Technical Information of China (English)

    陈雷; 徐雁飞

    2011-01-01

    与ALC墙板相连的高频焊接H型钢柱与单纯钢柱的抗火承载力将会有所差别,文章通过有限元分析,研究了墙板对火灾下钢柱的抗火承载力影响和钢柱在火灾下的特性;将有限元分析结果与规程计算结果进行比较,验证了有限元分析的可靠性,并在此基础上分析了荷载比和截面温度梯度,为带墙板的钢柱抗火设计提供依据.%The fire-resistant bearing capacity of high-frequency welded H steel column with ATC wall board attached is different from that of pure steel column. Through the finite element analysis, the effect of wall board on the fire-resistant bearing capacity of steel column in fire is studied as well as the properties of steel column in fire. The results of the finite element analysis are compared with those of the calculation according to related standard, which validates the reliability of the finite element analysis. The relevant parameters are also analyzed including bearing ratio and section temperature gradient. The study can promote the fire-resistant design of steel column with wall board.

  20. Performance of a New Beam-Column and Concrete-filled Steel Tubular Column-Flat Plate Composite Structure%新型梁柱-钢管混凝土板柱混合结构试验研究

    Institute of Scientific and Technical Information of China (English)

    张玉敏; 苏幼坡; 苏经宇

    2013-01-01

    The new beam-column and concrete-filled steel tubular column-flat plate composite structure is characterized by the joint with dedicated connection device ( hinged connection) between steel columns and concrete slab. The nodes bear only vertical loads while the horizontal loads are born by the shear wall and beam-column frame, and the unbalanced moment in the joint should be very small even naught to avoid the punching damage of slab when an earthquake occurs. The new structure is different from the general frame-shear wall or slab-column structure, therefore the experiment should be implemented to study the performance of the floor system. Through a model test of concrete filled steel tubular (CFST) column-flat plate structure (inter-cross with less than 3) with 1/2-scale, the mechanical performance should be studied under vertical uniform and horizontal loads. Results show that the bearing capacity of the floor system with high security reserves is 2 times higher than the vertical design load; the relative displacement of the joint can achieve 2. 25 % of storey height that is two times more of a frame structure's story drift limit in Code for Seismic Design of Building Structure before the specimens were destroyed even in high ratio of shearing force from the weight of superstructure and punching shear capacity of slabs (gravity shear ratio, GSR >0. 8) . The seismic behavior exceeds ordinary flat floor slab.%新型梁柱-钢管混凝土板柱混合结构的特点是钢管混凝土柱-板节点处只承担竖向荷载,不出现或者出现较小的不平衡弯矩,同时提高节点抗侧移能力,避免地震时楼板发生冲切破坏,水平荷载则全部由抗震墙和梁柱框架承担.通过1个1/2比例钢筋混凝土梁柱-钢管混凝土柱无梁楼盖异型板(跨数少于3跨)结构模型试验,研究其在受竖向均布荷载和水平荷载作用下结构的受力性能.试验结果表明,楼盖系统的竖向承载力超出设计荷载的2倍以上,

  1. 新型钢柱脚抗震性能分析%Researches on seismic behaviors of a new kind of steel column base

    Institute of Scientific and Technical Information of China (English)

    胡郢; 雷劲松; 罗文霞

    2011-01-01

    为研究在普通露出型钢柱脚上安装楔块装置的新型钢柱脚的抗震性能,采用通用有限元软件ANSYS建立了该柱脚两种常用形式下的三维实体模型,在低周反复加载作用下对其进行了抗震性能分析.根据有限元分析所得该柱脚的M-θ滞回曲线,及M-θ骨架曲线,对新型柱脚耗能能力和延性性质做了相关研究.同时,对比分析了不同轴压和不同形式柱脚的力学性能.结果表明:新型钢柱脚的恢复力特性为非滑移型,其M-θ滞回曲线饱满,并有较好耗能和延性性能,显示出良好的抗震性能.研究结果对新型柱脚的设计和应用提供了相关参考.%To research the seismic behaviors of a new kind of steel column based with wedge devices, the finite element software ANSYS is used to build three dimensional models for two commonly used types of the column bases and the analysis of seismic behavior of the column base under the low cyclic loading is conducted.The M - θ hysteretic curves and M - θ skeleton curves of the column base are obtained from the finite element analysis.The energy dissipation capacity and ductility are also researched from the curves.Comparisons between different types of the column base and different axial compressions are conducted.The results show that the restoring characteristics of the new kind columns are non-slip-type.The M - θ hysteretic curves of bases are plumpy and have good energy dissipation capacity and ductility.These indicate good seismic abilities of the column base.The results provide references for the design and application of the new kind column base.

  2. Forecast Models for Estimating Construction Cost of Box Steel Column%钢结构箱型柱施工费用预估模式的研究

    Institute of Scientific and Technical Information of China (English)

    徐凌; 吕录娜; 邓光莲

    2016-01-01

    过去钢构制作进度预估及成本估价皆为经验法,导致施工进程须依个案加以规划。本研究利用施工现场生产力数据与影响因子,希望能建置一套施工费用预估模式。研究结果发现箱型柱制作作业具有高度重复及线性循环等特性。因此,本研究以线性回归方法建置钢结构箱型柱作业生产力预估模型。由于建置施工费用预估模式能够规划有效进程、方便管控预算成本及控制施工成本,因此可供钢结构厂预估最佳工期与成本,以减少预算损失[1]。%In the past, steel production cost and progress prediction are empirical method, leading to the construction process in accordance with the case of planning. The construction site and the influence factor of productivity data are used in this study, hoping to establish a prediction model of construction cost. The research results show that the production operation of box column has the characteristics of high repetition and linear cycle. Therefore, based on the linear regression method, this study builds the steel box column work productivity prediction model. Because the implementation of construction cost estimate model can effectively plan the process, conveniently control the budget and the construction cost, it can be used to estimate optimum duration and cost for steel structure factory in order to reduce the loss budget.

  3. 陕西科技信息大厦钢管混凝土施工%CONSTRUCTION OF STEEL TUBE ENCASED CONCRETE COLUMN FOR SHAANXI SCIENCE AND TECHNOLOGY INFORMATION TOWER BUILDING

    Institute of Scientific and Technical Information of China (English)

    梁睿鑫

    2001-01-01

    This paper introduces the structural characteristics, jobpractice and quality requirements of the steel tube encased concrete column for Shaanxi Science and Technology Information Tower Building, which includs the fabrication and erection of the steel tube column, embedment of the base plate, construction of the compensated contracting concrete, slump control, pouring concrete from a high position and vibration as well as the inspection method of the quality of the steel tube encased concrete column.%介绍陕西科技信息大厦钢管混凝土柱结构特点、施工工艺和质量要求,包括钢管柱制作、安装、底座埋设、补偿收缩混凝土施工、坍落度调整、高位抛落并振捣的方法及钢管混凝土柱质量检查方法.

  4. 某超限高层建筑钢管混凝土柱设计%Design of steel tube concrete column of the out-of-codes high-rise building

    Institute of Scientific and Technical Information of China (English)

    刘东铭

    2012-01-01

    This paper analyzes the advantages of steel tube concrete column used in the out-of-codes high-rise building,and mainly explores the technological design points of steel tube concrete beam-column joint.Through rational design,the high-rise building achieves good economic benefits by applying steel tube concrete column.%对钢管混凝土柱用于超高层建筑的优势进行了分析,着重对钢管混凝土梁柱节点设计技术要点进行了探讨,通过合理的设计,超高层建筑采用钢管混凝土柱可取得较可观的经济效益。

  5. Dynamic Response Analysis of Concrete Rectangular Steel Tube Columns Under Blasting Loading%爆炸荷载作用下方钢管混凝土柱的动力响应分析

    Institute of Scientific and Technical Information of China (English)

    孙宇; 毛毳; 杜欣新

    2015-01-01

    使用 ANSYS/LS-DYNA 软件,建立 TNT 炸药、空气域以及方钢管混凝土柱的三维计算模型,模拟钢管混凝土柱在爆炸荷载作用下的动力响应,得到方钢管混凝土柱的整体响应、柱中部位移、压力以及破坏模式。结果显示:在爆炸荷载作用下,方钢管混凝土柱中部破坏最为严重,为弯曲破坏;柱脚发生剪切破坏;柱顶端出现高应力区,但并未发生严重破坏。说明由于钢管对于核心混凝土的约束作用,柱子的韧性和塑性得到较大幅度的提升。%3D calculation model of TNT explosive,air domain and concrete rectangular steel tubular column are established by software ANSYS/LS-DYNA. To obtain the overall response and central displacement of concrete rectangular steel tubular columns,pressure,and failure mode,the dynamic response of concrete rectangular steel tube columns under blast loading is simulated. The results show:that the explosive destruction in middle part of the steel tube concrete column is most serious, which is bending failure;the root of column shear is failure;the high stress area exists in the column top,but has no serious damage. The results of this study show that,due to the steel tube,concrete filled steel tube has higher toughness andplasticity in three dimensional stress states.

  6. Experimental Study on Seismic Behavior ofSeismic-damaged Lateral Joints in CompositeFrame Consisting of CFSST Columns and SteelBeams Strengthened with Enclosed ReinforcedConcrete

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    A new composite strengthening method of seismic-damaged lateral joints in composite frame consisting of Concrete-Filled SquareSteel Tubes (CFSST) columns and steel beams strengthened with enclosed Reinforced Concrete (RC) at the ends of columns andwelding steel plates at the ends of beams was presented. Based on the current design specifications, one half scaled models of 4lateral joints in composite frame consisting of CFSST columns and steel beams were designed and manufactured. One model wasoriginal control specimen, one was strengthened by enclosed RC, and the others were strengthened after pre-damage. The destructiontests under lateral cyclic load on the models were carried. The effectiveness of seismic-damaged joints strengthened with enclosedRC and the reinforcement effect on different levels of seismic damage were studied. The test results show that seismic- damagedjoints in composite frame consisting of CFSST columns and steel beams strengthened with enclosed RC meets the strongcolumn-weak beam joints requirement of seismic design, and the failure modes are of all joints are the bending failure of steel beam.The reinforcement with enclosed RC has a significant on increasing the ultimate capacity and the seismic behaviors of joints. Thestudy indicated the rehabilitated joints recover the level of their original seismic performances before seismic damage in a certainextent damage level. Based on the test data, namely the ultimate capacity, limit displacement, ductility, the energy consumptioncoefficient, limit displacementthe strengthening method of seismic-damaged joints by strengthened with enclosed RC is an effectivemethod for seismic strengthening.

  7. Research on the seismic performance of bare steel column base%外露式钢柱脚节点抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    宋岩; 王永

    2013-01-01

    为了研究外露式钢柱脚节点抗震性能和提高外露式柱脚抗震设计的可靠性,本文针对外露式柱脚连接节点的抗震性能进行了试验研究,将两组不同的柱脚试件在循环反复荷载作用下的整体响应和各组成单元的局部响应情况进行对比.根据试验结果,分析柱脚节点在地震作用下的破坏特征、滞回特性、骨架曲线、延性及耗能指标.试验结果表明:两个试件的初始刚度基本接近,但是无翼缘支撑板的柱脚刚度退化要明显快于有翼缘支撑板的柱脚;有翼缘支撑板的柱脚的延性系数比无翼缘支撑板的柱脚提高约28.7%,而耗能系数提高约10.1%;翼缘支撑板可以提高柱脚的连接强度和承载能力,使得节点区域各构件的协同作用加强;柱脚区域的力学特性表明其破坏形式为半刚性特性且在柱根部出现塑性铰.%In order to research the seismic performance of bare steel column base and to improve the reliability of its designation,this thesis by experimental research contrasts the whole response and the local response of two different base samples under cyclic loading reversals and it also analyses the column base's failure characteristic,the hysteretic behavior,skeleton curve,ductility and capability of energy dissipation. The result shows that the initial stiffness of two specimen are similar,but the stiffness of column base with flange-supporting board is weakening slower than the speed of column without flange-supporting board;the former column's ductility is higher by 28.7% than the latter, and its capability of energy dissipation is higher than the latter by 10. 1%. It concludes that the flange-supporting board can improve the column's connection and loading capability to strengthen the cooperative function of the node components and the mechanical characteristics of column shows that its destructive form is semi-rigid and can appear plastic hinges.

  8. Comportement des poteaux composites en profils creux en acier remplis de béton Behavior of composite columns in hollow steel section filled with concrete

    Directory of Open Access Journals (Sweden)

    Othmani N.

    2012-09-01

    Full Text Available Le but de cet article, est la determination des rigidites flexionnelles EIx et EIy d’fune section mixte acier beton et plus precisement d’fun poteau en tube d’facier de section rectangulaire, remplie de beton, sollicitee a la flexion bi-axiale (N, Mx et My. L’festimation des rigidites sera faite a partir d’fune approche theorique par une analyse du poteau en elements finis (element barre a 4 degres de liberte, basee sur les conditions d’fequilibres a mi-portee en utilisant la relation moment-courbure (M–Φ de l’felement deforme par application de l’fequation suivante: EI=M/Φ. Le comportement des materiaux est celui comme adopte par les reglements Eurocode 2 et 3, respectivement pour le beton et l’facier. Afin de valider l’fapproche theorique utilisee dans cette etude, deux comparaisons ont ete faites : une premiere permettant de comparer les resultats des rigidites determinees par les relations moments courbures et celles calculees par l’fEurocode 4 et une deuxieme comparaison entre les charges de ruines de deux poteaux de grandeurs natures avec ceux testes au laboratoire [2]. Au vu des resultats obtenus, nous pouvons conclure que l’approche théorique utilisée dans cette étude ainsi que les modèles de comportement des matériaux sont adéquats pour ce genre de problèmes. The purpose of this paper is the determination of flexural stiffness EIx and EIy of a concrete filled rectangular cross section of a composite steel column, under biaxial bending (N, Mx and My. The rigidities will be estimated from a theoretical approach using a finite element analysis (element bar with 4 degrees of freedom, based on the equilibrium conditions at mid-span using the moment-curvature relationships (M–Φ of the deformed element by applying the following equation: EI=M/Φ. The material behavior is the one adopted by Eurocode 2 and 3, respectively, for concrete and steel. To validate the theoretical approach used, two comparisons

  9. 强约束轴心受压钢管柱耐火性能试验研究%Experimental study on the fire-resistance of steel tube columns with axial compression and strong constraints

    Institute of Scientific and Technical Information of China (English)

    屈立军; 潘翀; 李焕群

    2012-01-01

    为正确评估强约束钢管柱的耐火性能,利用自行研制的杆系结构构件温度轴力测量装置,采用恒载升温试验方法,设5级初应力水平,6种长细比,对30根Q345钢管柱进行试验研究,揭示轴心受压钢管柱在强约束下的耐火性能。试验结果表明:强约束钢管柱在温升作用下的温度应力相当大,对钢管柱破坏有决定性作用,在耐火设计与评估中必须考虑。钢管柱在高温作用下,破坏前其弹塑性性质较为明显。相同长细比的构件,在较高的初始应力水平作用下,极限承载力大、温度应力小、临界温度低;反之相反。在相同初应力水平下,长细比对强约束钢管柱的极限承载力和温度应力的影响并不敏感,但长细比大的试件为失稳破坏,破坏后变形很大;长细比较小的试件为强度破坏,破坏后变形较小。以试验数据为基础给出两端固定Q345钢管柱的下限临界温度回归计算公式,可用于火灾中约束刚度不变的钢结构耐火设计与评估。%In order to evaluate the fire resistance of steel tube columns with strong constraints, a self-developed thermal internal force measurement device for frame structure members was employed. Test under elevated temperature and constant loading was conducted for 30 steel tube columns of Q345 with 5 grades of initial stress levels and 6 slenderness ratios, to reveal the fire resistance of such columns. The results show that under elevated temperature the thermal stress of the steel tube columns is great, and should be considered in the fire resistance design and evaluation. Under elevated temperature, the steel tube columns exhibite obvious elasto-plastic properties before failure. With identical slenderness ratio, the columns with higher initial stress level hadve larger bearing capability, lower thermal stress and critical temperature, when compared with the columns with lower initial stress levels

  10. 钢套法加固方钢管混凝土柱抗震性能试验研究%Experimental research on seismic behavior of strengthened CFSST columns steel sleeve method

    Institute of Scientific and Technical Information of China (English)

    杨炳; 许成祥; 赵斌; 付晨曦; 彭威

    2015-01-01

    针对方钢管混凝土柱加固后的抗震性能进行了6根柱的低周反复荷载破坏试验,研究了外套钢套法和外包钢套法两种加固方法以及钢套壁厚、施焊和加固高度对加固效果的影响,分析了相应的加固机理。通过对试件的滞回曲线、骨架曲线、延性、耗能能力、承载力及刚度退化系数等参数的分析可知:钢套法合理加固保证了混凝土柱“强剪弱弯”抗震延性设计目标,其破坏形态均表现为压弯破坏;外套钢套法加固提高柱的承载力作用有限,但极大提高了混凝土柱的延性性能,使其抗震性能明显提高;外包钢套法加固显著提高了混凝土柱的承载力、刚度,使其延性性能有所改善,抗震性能显著提高。%In order to study the seismic behavior of concrete-filled square steel tubular ( CFSST ) column after reinforcement, a destruction test was carried out on six specimens under lateral cyclic loading. The influences of steel jacket and enveloped steel methods, wall thickness of the enveloped steel and welding and strengthening height on the reinforcement effect were studied, and their rein-forcement mechanism was analyzed. From the test data, the hysteretic loops, skeleton curves, duc-tility, dissipative ability, ultimate strength and stiffness degradation etc. , a conclusion was drawn:the CFSST column strengthened by the steel sleeve method meets the strong shear weak bending re-quirements in seismic design, and the failure modes of all columns are compression bending failure. The steel jacket method has notable influence on the ductility and the seismic performance of col-umns, but leads to limited increment to the ultimate strength. The enveloped steel method has sig-nificant improvements on the strength, the stiffness and all aspects of seismic performance of col-umns.

  11. Experimental study on seismic performance of concrete columns reinforced by steel-FRP composite bars%钢-连续纤维复合筋增强混凝土柱抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    孙泽阳; 吴刚; 吴智深; 张敏

    2011-01-01

    The seismic performance of concrete columns reinforced by Steel-FRP(Fiber Reinforced Polymer) Composite Bar(SFCB) is quite different from that of ordinary RC(Reinforced Concrete) columns.Horizontal cyclic loading tests were conducted on concrete columns reinforced by SFCB and ordinary steel bars,separately,with an axial compression ratio of 0.12.Fiber types(basalt and carbon fibers) and steel/fiber ratio of SFCB were the main variable parameters.Test results showed that: ①compared with ordinary RC column,concrete columns reinforced by SFCB had stable post-yield stiffness,and the load could increase significantly after the yielding of SFCB inner steel bar;②due to the post-yield stiffness of SFCB,SFCB reinforced concrete column had less column base curvature demand than ordinary RC column at the same column cap lateral deformation level,and therefore smaller unloading residual deformation could be achieved;③the outer FRP type of SFCB significantly influenced the performance of SFCB reinforced concrete columns,and steel-BFRP(basalt FRP) composite bar reinforced concrete columns had better ductility(longer effective length of post-yield stiffness) and smaller unloading residual deformation than steel-CFRP(carbon FRP) composite bar columns under the same unloading displacement.%具有稳定二次刚度和良好震后可修复性的钢-连续纤维复合筋(SFCB)增强混凝土柱的抗震性能与普通RC柱有较大差别,本文对在水平往复荷载作用下,轴压比为0.12的4个SFCB增强混凝土柱及1个RC对比柱的抗震性能进行试验研究。SFCB增强混凝土柱主要变化参数为SFCB中的纤维种类(玄武岩纤维和碳纤维)和钢/纤维比例。研究结果表明:①SFCB增强混凝土柱相对普通RC柱具有稳定的二次刚度,在复合筋内芯钢筋屈服后,SFCB增强混凝土柱承载力仍可稳定提高;②SFCB增强混凝土柱由于复合筋的二次刚度,实现了在与普通RC柱

  12. Experiments on seismic behaviors of beam-column combined components with steel reinforced concrete column-reinforced concrete beam encased steel truss%桁架式钢骨混凝土梁-钢骨混凝土柱梁柱组合构件抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    杨立军; 邓志恒; 冯超; 陈孔

    2016-01-01

    A new type of frame joint with steel reinforced concrete (SRC)column-reinforced concrete (RC)beam encased steel truss was put forward.Reversed cyclic loading tests on eight specimens were conducted to intensively investigate the seismic behaviors of the beam-column combined components.The failure processes of eight frame joints under low-cyclic reversed loading were observed and recorded.And the load-displacement hysteretic loops,shear behavior of the joint core,skeleton,curve,load-intersection angle hysteretic loops etc.of the test subassemblies were tested.Then the seismic behaviors such as the ductility,energy dissipation capacity,and strength and stiffness degradations were analyzed.The influential factors,such as the steel proportion,axial compression ratio and size of angle iron's web member,on the mechanical performance of joints were discussed.The results indicate that the joints with SRC column RC beam encased steel truss have good ductility and energy dissipation capacity.It provides theoretical basis for engineering application of this kind of structures.%提出了一种由桁架式钢骨混凝土(SRC)梁和钢骨混凝土(SRC)柱组成的框架结构新的节点形式。为了研究这种新型梁柱组合构件的抗震性能,对8个桁架式钢骨混凝土梁-钢骨混凝土柱框架边节点进行了低周反复荷载试验。试验观察并记录了各节点试件的破坏形态,测得其梁端荷载-位移滞回曲线、节点剪切变形、骨架曲线和梁端荷载-转角滞回曲线。以试验结果为基础,对节点的延性、耗能性能、承载力及刚度退化等抗震耗能性能进行了分析,讨论了含钢率、轴压比及角钢腹杆尺寸对节点受力性能的影响。研究结果表明,这种新型桁架式钢骨混凝土框架节点具有良好的延性及耗能性能,为其工程应用提供了理论依据。

  13. EXPERIMENTAL STUDY OF SEISMIC BEHAVIOR OF THE STEEL TUBULAR ASSEMBLY COLUMN%局部外包钢管装配整体式柱抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    李青宁; 何迪; 王鹏; 姜维山

    2014-01-01

    A new kind of precast concrete segmental columns has been put forward in this paper .Its core concrete is constrainted by high-strength compound spiral stirrups and the exterior steel plate hoop penetrated by the bolt bar used for the connection area .It is compared the three assembled long columns under different width of the exterior steel plate hoop and axial pressure ratio to the one cast-in-place long column .It is proved that the new kind of precast concrete segmental columns is better for the anti-seismic capacity and safe in the node connection area so that the cast-in-place long column can be replaced .ANSYS FEM software is used to take contrastive analysis for the column of hysteretic behavior based on the width of the exterior steel plate hoop and axial pressure ratio , the results show that numerical simulation meets well with the experiment , the ANSYS numerical analysis model of precast concrete segmental columns is feasible and correct .The ANSYS FEM can be used for the numerical simulation and the analysis of mechanical performance study of the assembled column structures .%提出一种高强复合螺旋箍筋约束混凝土、外包钢板箍和横穿栓筋连接的新型装配整体式柱。通过对不同钢板箍厚度和轴压比下的3个装配式长柱与1个现浇长柱进行拟静力对比试验,证明这种装配整体式柱抗震性能良好,节点连接安全可靠,可以代替现浇整体柱。以钢板箍厚度与轴压比为研究变量,利用ANSYS对柱的滞回性能进行对比分析,研究结果表明:数值模拟与试验吻合较好,提出的装配整体式柱ANSYS数值分析模型合理可行,可运用ANSYS程序对装配整体式柱结构进行有限元数值模拟和受力性能研究分析。

  14. 冷弯型钢双肢组合截面长柱轴压性能分析%Finite element analysis of cold-formed steel double-C section compression long columns

    Institute of Scientific and Technical Information of China (English)

    王群

    2012-01-01

    This paper use the ANSYS software program on cold-formed thin-walled steel open double limb column of combination section axial compression performance are analyzed, the open double limb column of combination section long columns under axial pressure under the effect of the failure mode and the ultimate bearing capacity, with a view to provide certain reference for analyzing similar structural performance.%使用ANSYS软件程序对冷弯薄壁型钢开口双肢组合截面立柱的轴压性能进行了分析,得出了在轴向压力作用之下,开口双肢组合截面立柱长柱的破坏模式和极限承载力,以期为类似结构的性能分析提供参考。

  15. Seismic Behavior of SCFT Column-H Section Steel Beam Plane Frame%SCFT柱-H型钢梁平面框架抗震性能分析

    Institute of Scientific and Technical Information of China (English)

    王亚雯; 闫翔宇; 周婷

    2015-01-01

    In this paper,SCFT column-H section steel beam plane frame is analyzed through establishing nonlinear finite element models by ANSYS. Seven sets of models were built under low cyclic loading conditions. The mechani-cal characteristics of these frame models were simulated. The axial compression ratio was set to be the control variable,and the influence of infilled wall on the frame was studied as well. The result shows that all the sevensets of models present symmetrical and smooth plumped hysteretic curves under low cyclic loadings,and the decending segment of the skeleton curve is slightly inclined;after mono-steel tube column reaches its yield strength in the com-pression section,the entire SCFT can still take more load as an integrated member,and therefore it delays the plastic deformation of the frame,showing its preferred earthquake resistant capacity;no promising evidence shows that the axial compression ratio has a strong influence on the frame’s stiffness degradation,however,as the ratio increases, the ultimate bearing-capacity and displacement ductility both decrease,and the strength decreases obviouslyafter it has reached ultimate bearing-capacity;the infilled wall bears a considerable amount of lateral load at the earlystage of loading,increasing the bearing-capacity and elastic stiffness of the plane frame obviously. Considering that the rigid connection to infilled wall results in early crash of the wall,it is suggested that flexible connections or extension joints between the frame and infilled wall should be adopted in practical constructions to reduce the damage.%针对SCFT柱-H型钢梁平面框架,采用ANSYS建立非线性模型,进行了7组框架模型在低周反复荷载作用下的受力特性分析,研究了轴压比和有无填充墙对SCFT柱框架力学性能的影响规律。分析发现:7组框架模型滞回曲线饱满,骨架曲线下降段平缓;在受压单肢钢管受压区达到屈服强度时,SCFT 柱仍可视

  16. 不同剪跨比下型钢再生混凝土柱抗震性能试验研究%Experimental study on seismic behavior of steel reinforced recycled concrete column under different shear-span ratios

    Institute of Scientific and Technical Information of China (English)

    薛建阳; 马辉

    2013-01-01

    In order to investigate the failure patterns and seismic performance of steel reinforced recycled concrete columns,four column specimens with different shear span ratio of steel reinforced recycled concrete were tested under low cyclic reversed loading.The failure process and patterns were observed.The mechanical behaviors,such as load-displacement hysteretic loops and skeleton curves,load carrying capacity,ductility,energy dissipation capacity and stiffness degradation of steel reinforced recycled concrete columns were analyzed.Test research results show that the shear diagonal compression failure,shear-bending failure and bending failure are the main patterns of steel reinforced recycled concrete columns.The load carrying capacity of specimens reduces with the increase of shearspan ratio,but the load-displacement hysteretic loops are plumper and the descending of load carrying capacity is relatively slow.It also shows the stiffness degradation rate is slower and the ductility or energy dissipation capacity is greater with the increase of shear span ratio.Overall,the steel reinforced recycled concrete columns with high shear-span ratio behave well in seismic performance.It can be used in the practical engineering.%为研究型钢再生混凝土柱的破坏形态和抗震性能,进行了4个不同剪跨比的型钢再生混凝土柱低周反复荷载试验,观察了其受力过程及破坏形态,分析了剪跨比对柱的滞回曲线、骨架曲线、承载力、延性、耗能及刚度退化等力学性能的影响.研究结果表明:根据剪跨比的不同,型钢再生混凝土柱的破坏形态主要为剪切斜压破坏、弯剪破坏以及弯曲破坏.随着剪跨比的增大,试件水平承载力降低,但滞回曲线愈加饱满,承载力下降越缓慢,刚度退化速率越慢,延性及耗能越好.总体上看,剪跨比较大试件的抗震性能较好,可以用于实际工程.

  17. 薄壁波纹钢管混凝土柱滞回性能试验研究%Experimental study on the hysteretic behaviors of thin-walled corrugated concrete-filled steel tube column

    Institute of Scientific and Technical Information of China (English)

    高剑平; 吴永根; 霍静思

    2012-01-01

    近年来,薄壁钢管混凝土柱由于其良好的力学性能和施工性能在各类建筑结构和桥梁上得到了广泛应用,但震害表明,普通薄壁钢管混凝土柱抗局部屈曲能力和屈曲后抗震性能较差.提出了一种薄壁波纹钢管混凝土柱,为了初步探索其抗震性能,以轴压比和截面形式为主要参数,进行了2根薄壁波纹钢管混凝土柱和2根普通薄壁钢管混凝土柱低周反复加载试验研究.主要结论如下:在轴压比相同的情况下,薄壁波纹钢管混凝土柱的滞回曲线明显要比其它两种截面形式的饱满;在相同位移时,薄壁波纹钢管混凝土柱的耗能能力明显好于方形和圆形的.三种截面形式的延性较接近且延性系数均超过3,且强度退化和刚度退化趋势和程度基本一致.综合分析,薄壁波纹钢管混凝土柱抗震性能较之圆、方形薄壁钢管混凝土柱的相当或稍好.研究结果可供城市高架桥的分析与设计参考.%In recent years, thin-walled concrete-filled steel tube column ha been widely used in many types of building structures and bridges, owing to its good mechanical properties and construction performance. However, the local buckling capacity and post-buckling seismic capacity of common thin-walled concrete-filled steel tube column are poor. A new-style thin-walled corrugated concrete-filled steel tube column was proposed. A low cyclic loading test was conducted to study its seismic performance with axial-compression ratio and section form as the main parameters. The main conclusions are as follows; the hysteresis loops of thin-walled corrugated steel concrete column are fuller than those of the other two section forms under the same axial-compression ratio. The dissipation energy capacity of thin-walled corrugated steel concrete column is better than that of square and circle under the same displacement condition. The ductility coefficients of the three section forms are close and all

  18. Effective length factor of column in sway steel frames with dog-bone connections%梁削弱式节点连接的侧移钢框架柱计算长度系数

    Institute of Scientific and Technical Information of China (English)

    王万祯; 冯翔; 许继祥

    2009-01-01

    根据框架柱计算长度理论,通过引入梁削弱式节点参数特性,建立了四跨三层的梁削弱式节点连接的侧移钢框架数值模型.利用ANSYS软件对梁削弱式节点连接的侧移钢框架数值模型进行了非线性屈曲分析,得到了梁削弱式节点连接的侧移钢框架柱计算长度系数.结果显示,梁削弱式节点侧移钢框架柱计算长度系数较常规节点增加1.5%~12.9%.最后,经过回归得到了梁削弱式节点连接的侧移钢框架柱计算长度系数建议公式.%According to the column-effective length theory of steel frames stability design,and by considering the characters of dog-bone connections,and finite element models of four-span three-story sway steel frames with dog-bone connections were established using ANSYS program. Through nonlinear bucking analysis of sway steel frames with dog-bone connections, the effective length factors of sway steel frames were derived. Simulation results showed that the effective length factor of sway steel frames with dog-bone connections increased within the range of 1.5% to 13 % in comparison with that of sway steel frames with conventional connections. The suggested formula, which was fit for sway steel frames with dog-bone connections, was gained by regression analysis.

  19. 薄壁波纹钢管混凝土柱局部屈曲性能研究%Study on the local buckling behavior of thin corrugated steel pipe concrete column

    Institute of Scientific and Technical Information of China (English)

    朱哲清; 高剑平; 罗民

    2014-01-01

    对一种新型的薄壁波纹钢管混凝土柱进行了低周反复荷载作用下滞回性能试验研究,然后利用ABAQUS进行模拟分析,分析了钢板截面宽厚比、长细比、钢板强度、混凝土强度等4个因素对薄壁波纹钢管混凝土柱局部屈曲的影响规律。试验结果表明:薄壁波纹钢管混凝土柱宽厚比、长细比基本与屈曲荷载成反比,钢板强度与屈曲荷载成正比,混凝土强度基本与屈曲荷载无关。%This paper presents an experimental research of hysteretic performance on a new kind of thin wall corrugated steel pipe concrete column under the effects of low cyclic load. The simulation analysis is carried on by ABAQUS towards the influence of such four factors as steel cross-section width-thickness ratio, slenderness ratio, steel strength, concrete strength on the thin wall corrugated steel pipe concrete column local buckling. The main conclusions are as follows: there is an inverse correlation between its width to thickness ratio, slenderness ratio and local buckling load; steel strength is proportional to the load; concrete strength has no effect on the load.

  20. Slender CRC Columns

    DEFF Research Database (Denmark)

    Aarup, Bendt; Jensen, Lars Rom; Ellegaard, Peter

    2005-01-01

    CRC is a high-performance steel fibre reinforced concrete with a typical compressive strength of 150 MPa. Design methods for a number of structural elements have been developed since CRC was invented in 1986, but the current project set out to further investigate the range of columns for which...

  1. Study on seismic behavior of bottom strengthened rectangular concrete filled steel tube columns%底部加强型矩形钢管混凝土柱抗震性能试验与分析

    Institute of Scientific and Technical Information of China (English)

    惠存; 曹万林; 董宏英; 许方方

    2012-01-01

    提出了一种底部加强型矩形钢管混凝土柱,采取在柱底部区域钢板外侧贴焊钢板的构造措施,以提高其抗震耗能能力.进行了3个不同构造的矩形钢管混凝土柱模型的低周反复加载试验,模型1为普通矩形钢管混凝土柱,模型2为矩形截面底部垂直加载方向钢板外侧贴焊钢板的钢管混凝土柱,模型3为矩形截面底部双向外侧钢板均贴焊钢板的钢管混凝土柱.模型按1/5缩尺.分析了各模型的承载力、刚度及退化过程、延性、滞回耗能特性和破坏特征.给出了底部加强型矩形钢管混凝土柱正截面及斜截面承载力的计算公式,计算与实测结果符合较好.研究表明:所提出的底部加强型矩形钢管混凝土柱与普通矩形钢管混凝土柱相比,其承载力明显提高,延性和抗震耗能能力显著提高.%The bottom strengthened rectangular concrete filled steel tube (CFST) column was put forward. The bottom area of the rectangular column was welded with steel plates to improve its seismic energy dissipation capacity. Three 1/5 scaled column models with different construction measures were tested under horizontal low cyclic loading. Model 1 is a conventional rectangular CFST column; Model 2 is a rectangular CFST column welded with steel plates at the outer bottom part vertical to the direction of loading; Model 3 is a rectangular CFST column welded with steel plates around lateral side of the bottom of the column. The load - bearing capacity, stiffness and degradation process, ductility, hysteretic energy dissipation capacity and failure characteristics of the models were analyzed. The calculation formula of load - bearing capacity of bottom strengthened rectangular CFST column for normal section and oblique section was given, and the results agree well with those from the experiments. The study shows that the load - bearing capacity, ductility and seismic energy dissipation capacity of the bottom strengthened

  2. Experimental Study on Seismic Behavior of Composite Core Walls With Steel Tube-reinforced Concrete Columns%钢管混凝土叠合柱边框组合核心筒抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    董宏英; 耿海霞; 张建伟; 曹万林; 杨信强

    2011-01-01

    为了比较带钢管混凝土叠合柱边框组合核心筒与带钢管混凝土边框组合核心筒的抗震性能,进行了1个钢管混凝土叠合柱边框组合核心筒模型和1个钢管混凝土柱边框组合核心筒模型的低周反复荷载试验研究,2个模型均按1/6缩尺.在试验基础上,分析比较了2个核心筒的承载力、延性、滞回特性、刚度及其衰减过程、耗能能力和破坏特征.研究表明,钢管混凝土叠合柱边框组合核心筒比钢管混凝土柱边框组合核心筒的抗震性能显著提高;承载力简化计算模型的计算结果与实测结果符合较好.%The cyclic tests are performed in order to compare the seismic behavior of two 1/6 scale composite core walls with different columns, one with concrete filled steel tube columns and the other with steel tubereinforced concrete columns. Based on the experiment, load-carrying capacity, ductility, hysteretic property, stiffness and degradation, energy dissipation and damage characteristics of the two specimens are compared. It is shown that the seismic behavior of the core walls with steel tube-reinforced concrete columns is better than those with concrete filled steel tube columns. The mechanical model for calculating load-carrying capacity of the new RC composite core walls is proposed. And the calculating results agreed well with the results from the experiments.

  3. 钢框架结构顶底角钢梁柱连接滞回性能研究%Research on Hysteretic Behavior of Top-Seat-Angle Steel Beam-Column Connections

    Institute of Scientific and Technical Information of China (English)

    李凤霞; 布欣; 王新武

    2011-01-01

    The hysteretic behavior of top-seat-angle steel beam-column connections under cyclic loading is presented and fullscale model of top-seat-angle steel connections is analyzed by using ANSYS. The failure mechanism and ultimate deformation of topseat-angle steel beam-column connections are analyzed. Then the preload of bolt, the contact pressure of components and the mechanical properties between other components of the connections are studied. These results can provide good reference for the engineering design.%通过对顶底角钢粱柱连接原型模型进行循环荷载作用下的试验研究,以及对试验模型进行非线性有限元分析计算,全面分析了顶底角钢梁柱连接节点在循环荷载作用下的破坏机理和极限变形状态,研究了高强螺栓预紧力,角钢与梁、柱之间的接触压力等节点组件之间的力学特征,对工程设计有重要的参考价值.

  4. Analytical properties of axially loaded lightweight aggregate concrete filled circular steel tubular stub columns%圆钢管轻骨料混凝土轴压短柱的力学性能分析

    Institute of Scientific and Technical Information of China (English)

    丁发兴; 应小勇; 余志武; 欧进萍

    2011-01-01

    分析现有钢管轻骨料混凝土轴压短柱力学性能实验结果,提出轻骨料混凝土轴对称三轴受压轴向应力-应变关系,应用连续介质力学,确立圆钢管轻骨料混凝土同心圆柱体共同受压时的计算模型,建立了圆钢管轻骨料混凝土组合弹性模量理论计算公式和组合应力-应变关系的理论表达式,编制相应计算程序.结果表明,核心混凝土由于受钢管约束,其纵向应力有较大提高,延性得到显著改善,钢管在为轻骨料混凝土提供径向约束的同时,其纵向应力大幅降低;钢管对轻骨料混凝土的约束效果要低于对普通混凝土的约束效果.通过大量参数分析,得到钢管轻骨料混凝土轴压短柱极限承载力计算公式和组合应力-应变关系全曲线,计算与实验结果吻合良好.%Based on the experimental results of mechanical properties of lightweight aggregate concrete filled circular steel tubular (LCFST) stub columns under axial compression, the axial stress-axial strain relations of concrete under axisymmetric triaxial compression were proposed. Based on continuum mechanics, the calculation model for LCFST stub columns of concentric cylinders of circular steel tube with concrete core under concentrically loaded conditions was determined. The theoretical calculation formulas for composite elastic modulus and composite stress-strain relations of the stub columns were presented. A FORTRAN program for the elasto-plastic analysis of LCFST stub columns under concentric loading was developed. The reliability of the present method and program was validated by the test results from references. The behavior of LCFST stub columns was analyzed. The analysis results indicated that for confinement by steel tube, the axial stress of lightweight aggregate concrete core increased greatly and the ductility was improved, while the axial stress of steel tube decreased rapidly for confinement effect. Compared with normal concrete filled

  5. Panel Local Stability of the Large Steel Box Column in Hefei Xinqiao Airport Building%合肥新桥机场大型箱形钢柱壁板稳定性研究

    Institute of Scientific and Technical Information of China (English)

    李德章; 李海锋

    2011-01-01

    合肥新桥机场航站楼钢结构由多榀大跨度格构一实腹式转换刚架组成,转换部位及弧形实腹梁柱构件受力异常复杂,且实腹箱形构件体量大、板件宽厚比大,已接近或超过国家设计规范的限值.目前,对这类大跨度结构中大尺寸箱形构件的受力性能研究很少,根据设计需要,对合肥新桥机场航站楼钢结构中外形轮廓尺寸最大、壁板最薄的箱形钢柱进行壁板稳定性研究.采用数值分析方法,分别对轴力最大和轴力最小的两根箱形钢柱进行壁板稳定性态和极限承载能力分析,得到了腹板临界屈曲模态、极限状态下的鼓曲位移值及箱形钢柱弹塑性临界剪力,并与地震反复作用下,腹板平面外最大鼓曲位移及箱形钢柱剪力进行比较判断.研究表明,在地震反复作用下,轴力最小的箱形钢柱腹板均处于弹性工作状态;轴力最大的箱形钢柱,在小震作用下,腹板保持在弹性状态,在大震作用下,腹板进入弹塑性状态,但该柱仍具有承载能力,满足抗震安全需要.%The steel terminal structure of Hefei Xinqiao Airport consists of dozens of large-span frames. The frames are composed of triangle trusses and box colunms. The loading behavior of the transfer members between truss and column and the arc beams are very complex. The width-thickness ratios of box members approach or exceed the limit of design code. However, few studies have focused on the loading behavior of large box members in those large-span structures at present. According to design demands, the panel stability of steel box columns with the largest size and thinnest web in Hefei Xinqiao Airport was studied in this paper.Using numerical analysis method, analyses of panel stability and the load-bearing capacity of steel box column with maximum or minimum axial forces were conducted. Then the critical buckling modes of the web panel,buckling deformation in the ultimate state and the elasto

  6. Axial compression behavior of square thin-walled steel tube-laminated bamboo composite hollow columns%薄壁方型钢管/竹胶板组合空芯柱轴心抗压性能

    Institute of Scientific and Technical Information of China (English)

    赵卫锋; 张武东; 周靖; 曹勇龙; 龙志林

    2014-01-01

    研究方形薄壁型钢管/多层竹胶板组合空芯柱(Square, thin-walled steel tube/multi-layered bamboo plywood composite hollow column,SBCC)的轴心抗压性能,揭示其受力破坏机理,为其工程应用提供试验和理论基础。考虑试件的截面尺寸、空心率及长细比对SBCC抗压承载力的影响,设计制作了15根轴心抗压试件,通过SBCC的抗压性能测试,考察测试过程中的破坏形态和变形特征,分析各因素对试件轴心抗压力学性能的影响规律。试验结果表明:SBCC轴心抗压失效主要有竹胶合板材料破坏、基体胶结面开胶破坏以及整体失稳破坏3种形态,总体上胶结面间的胶粘强度及长细比是决定破坏模式的主要因素。SBCC的轴心抗压承载力随组合柱竹净截面面积、空心率的增大而显著提高,随长细比的增大而降低。通过试验数据的非线性回归分析,建立了SBCC的轴心抗压承载力计算公式,公式估算结果与试验测试结果的误差在20%以内。该研究结果表明SBCC是一种轴心抗压性能较优异的钢/竹组合结构单元,可实现“以竹代木”,作为工程结构用材的应用前景广阔。%The development of laminated-bamboo has broadened the application range of bamboo material in the field of structural engineering. A new type of steel/laminated bamboo composite column was developed based on the existing bamboo composite element for constructing multi-story, pre-fabricated, column-supported, and bamboo-framed buildings, and named as square thin-walled steel tube/multi-layered bamboo plywood composite hollow column (SBCC). The core of the SBCC is a square thin-walled steel tube, and the exterior column consists of several high-strength bamboo plywood pieces (such as bamboo mat plywood) that are bonded together using a structural adhesive to form a composite hollow column. SBCCs are a new type of steel/bamboo composite with excellent physical and

  7. Analysis on factors influencing high-strength stainless steel strands reinforcing RC column%高强不锈钢绞线加固RC柱的影响因素分析

    Institute of Scientific and Technical Information of China (English)

    王嘉琪; 曹忠民

    2011-01-01

    Through experimental research and application of existing high-strength strands net-polymer mortar reinforcing RC column, it analyzes factors influencing high-strength stainless steel strands reinforcing RC column, and outlines the impacts of the reinforcing method on steel reinforced concrete column from three aspects of restrictive performance, seismic performance and bearing capacity, which has provided guidance for engineering design and further research.%通过已有的高强钢绞线网一聚合砂浆加固RC柱的试验研究和应用,对高强钢绞线网一聚合砂浆加固RC柱的影响因素进行了分析,并从柱的约束性能、抗震性能、承载力三个方面综述了该加固方法对钢筋混凝土柱加固效果的影响,可为工程设计和进一步研究提供指导。

  8. 不同构造措施的钢管混凝土边框钢板剪力墙抗震性能试验研究%Experimental Study on Seismic Performance of Steel-plate Shear Walls with Concrete Filled Steel Tube Columns and Different Constructional Measures

    Institute of Scientific and Technical Information of China (English)

    张建伟; 曹万林; 董宏英; 李刚; 张文江

    2011-01-01

    The steel-plate shear wall with concrete filled steel tube columns is a new type of composite shear wall. In order to assess the seismic performance of new shear walls with different constructional measures, experimental study of three specimens with the same shear span ratio 1-5 were carried out undercyclic loading: one with the steel plate and the steel tubes being connected by welding, one with the steel plate and the steel tubes being connected by bolts, and one with the steel plate and the steel tubes being connected by welding as well as with low opening ratio of holes in the steel plate. Based on the experiment , the damage characteristics, hysteretic behavior, load-carrying capacity, stiffness, ductility and energy dissipation of the specimens were contrastively analyzed. The experimental results showed that the connection type between the steel plate and the steel tubes, either in welding or in bolting, had little effect on the overall performance of the shear walls. Compare to the normal steel-plate shear walls with concrete filled steel tube columns, the load-carrying capacity, ductility, stiffness and energy dissipation of the perforated steel-plate shear walls with concrete filled steel tube columns had not obvious change under low opening ratio of holes.%钢管混凝土边框钢板剪力墙是一种新型抗震剪力墙,为了比较不同构造措施对该新型剪力墙抗震性能的影响,进行了3个剪跨比为1.5的钢管混凝土边框钢板剪力墙低周反复荷载试验.其中,试验模型1为墙体钢板与边框柱钢管焊接,试验模型2为墙体钢板与边框柱钢管螺栓连接,试验模型3为墙体钢板开孔并与边框柱钢管焊接.通过试验研究,比较了各剪力墙的破坏特征、滞回特性、承载力、刚度、延性以及耗能能力.结果表明:在墙体钢板与边框柱钢管的连接方式中,采用焊接或栓接对剪力墙的整体性能影响不大;与普通钢管混凝土边框钢板剪力墙相

  9. RESEARCH ON WELDING PROCEDURE OF STEEL TOWER COLUMN OF MAANSHAN YANGTZE RIVER HIGHWAY BRIDGE%马鞍山长江公路大桥钢塔柱焊接工艺

    Institute of Scientific and Technical Information of China (English)

    李彦国; 刘志刚; 吴江波

    2015-01-01

    马鞍山长江公路大桥钢塔采用Q370qE和Q420qE钢,针对该钢塔使用的中厚板焊接,选择合理的焊接方法、焊接坡口、焊接材料以及焊接工艺参数进行焊接试验,通过焊接工艺评定试验及试验数据分析发现,各项性能均满足设计和相关标准要求。该焊接工艺成功应用于马鞍山长江公路大桥钢塔柱的制作,可供同类桥梁钢结构焊接制作借鉴。%Q370qE and Q420qE steel were adopted for steel tower of Maanshan Yangtze River Highway Bridge . Reasonable welding process , welding groove , welding consumables and welding parameters were selected for medium thickness plate welding and welding test . The results of welding procedure qualification test and data analysis indicated that the properties could meet the requirements of relevant design standards .The selected welding procedure selected has been successfully used in the fabrication of steel tower columns of Maanshan Yangtze River Highway Bridge .This paper provided a reference for the welding fabrication of similar steel bridge projects .

  10. HPE液压垂直插入机施作钢管柱施工技术%HPE Hydraulic Vertical Inserting Machine Applied Construction Technology of Steel Pipe Column

    Institute of Scientific and Technical Information of China (English)

    朱元生

    2012-01-01

    This paper,based on the South Station in Wuhan Metro Steel Pipe Column construction practice,discusses in detail the vertical insertion of the HPE hydraulic facilities for steel column construction process principles,processes,operating points and quality control requirements.Test data proves that the advanced technology is reliable,can assure quality,solving problems in the traditional steel column installation such as no assurance of the security of artificial positioning,the complex construction process,long duration,high cost,and reduces the construction period of South Station by five months,to break the constraints bottleneck of duration%结合武汉地铁中南路站钢管柱施工实践,详细论述了HPE液压垂直插入机施作钢管柱施工技术的工艺原理、工艺流程、操作要点和质量控制要求。检测数据证明,该技术先进可靠,能保证质量,突破了传统钢柱安装人工定位存在的安全不能保障、施工工序复杂、工期比较长、成本较高等诸多难题,并使中南路车站施工工期提前了5个月,打破了工期制约的瓶颈。

  11. Electrochemical characteristics on corrosion of steel reinforced concrete columns wrapped with fiber reinforced polymer%FRP 加固混凝土柱钢筋锈蚀电化学特性

    Institute of Scientific and Technical Information of China (English)

    卢亦焱; 齐波; 李杉; 李娜

    2015-01-01

    通过外加电流加速试验获得锈蚀钢筋混凝土柱,采用纤维增强聚合物(FRP)全裹方法对其进行加固,然后通过盐溶液干湿交替方法对FRP加固柱进行钢筋锈蚀试验,利用电化学工作站量测FRP加固柱的钢筋半电池电位和线性极化曲线,分析FRP加固柱的钢筋锈蚀电化学特性。试验结果表明:随着干湿交替次数的增加,外粘CFRP和GFRP加固柱的钢筋半电池电位呈先升高后稳定趋势,线性极化电阻呈增大趋势,腐蚀电流密度呈降低趋势;外粘CFRP和GFRP加固法均能在一定程度减缓钢筋混凝土柱的钢筋锈蚀,CFRP延缓钢筋锈蚀效果优于GFRP 。%Reinforced concrete (RC) columns were corroded through impressed current accelerated test and then treated with surface bonded fiber reinforced polymer (FRP). Following cure of the res‐in ,all of specimens were put into wet‐dry environment. During the test ,the half‐cell potential and linear polarization curve measures were recorded once 2 numbers of wet‐dry cycles through electro‐chemical w orkstation. Electrochemical characteristics of reinforcing bars embedded in FRP w rapped RC columns were analyzed. The tested results show that ,with the increasing of numbers of wet‐dry cycles ,the carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) w rapped RC columns have increasing trend in the linear‐polarization resistance and reducing trend in corrosion current density. While half‐cell potential of reinforcing bars of CFRP and GFRP w rapped RC columns display increasing in first 2 numbers of wet‐dry cycles and then remaining constant. RC columns that treated with surface bonded CFRP or GFRP strengthening method retard corrosion of steel bars in a certain degree. The efficiency of retarded corrosion of steel bar for RC columns wrapped with CFRP is better than that of RC column wrapped with GFRP.

  12. Q460C高强度钢柱滞回性能有限元分析%Finite element analysis on hysteretic behavior of Q460c high strength steel box-section and H-section columns

    Institute of Scientific and Technical Information of China (English)

    李国强; 王彦博; 陈素文; 崔嵬

    2013-01-01

    为进一步研究Q460C高强度钢柱的滞回性能,在已有试验研究的基础上,采用通用有限元分析软件ANSYS建立了数值模型,对Q460C高强度钢材焊接箱形和H形截面柱在常轴力和水平往复荷载作用下的滞回性能进行模拟,并研究了残余应力对高强度钢试件滞回性能的影响.将有限元分析结果与已有试验结果进行对比,两者吻合较好.研究结果表明:采用提出的Q460C高强度结构钢滞回模型进行有限元分析,能较为准确的预测Q460C高强度钢材焊接H形和箱形柱的滞回性能;试件内残余应力对Q460C高强度钢材焊接H形和箱形截面柱的滞回性能影响较小.%In order to further study the hysteretic behavior of Q460C high strength steel columns, a finite element ( FE) model was built up by using general FE analysis software ANSYS based on previous experimental study. Both welded box and H-section columns under constant axial load and horizontal cyclic loading were simulated. Moreover, the effect of residual stresses on the hysteretic behavior of Q460C steel welded box and H-section columns was evaluated. The FE analysis result shows good agreement with the existing experimental results conducted by authors. The proposed hysteretic model for Q460C high strength steel is proved to be accurate to be implemented in the numerical analysis. The comparison of FE analysis results with and without considering initial residual stresses shows that the influence of residual stresses on hysteretic behavior of Q460C high strength steel columns is negligible.

  13. 钢管再生混凝土长柱轴压受力性能试验研究%Experimental research on mechanical behavior of recycled aggregate concrete filled circular steel tubular long columns under axial compression loading

    Institute of Scientific and Technical Information of China (English)

    吴炎海; 方映平; 冯文贤; 蔡杨

    2015-01-01

    Axial static loading test was carried out on 6 recycled aggregate concrete filled circular steel tubular long columns. The whole loading process and failure modes were observed,and the curves of specimens about load-deformation and load-strain were plotted. The influences of the test parameters namely slenderness ratio and confine-ment index on deformation and the bearing capacities of specimens were analyzed. By domestic and foreign relevant specifications,the ultimate bearing capacity of the specimens were calculated and compared with the measured val-ues. The results indicated that the failure process of recycled aggregate concrete filled steel tubular long columns un-der axial compression includes elastic stage,elastic-plastic stage and plastic stage,and all the failure modes are elas-tic-plastic instability;Both the slenderness ratio and confinement index affect the mechanical performance of recy-cled aggregate concrete filled steel tubular long columns under axial loading,and the confinement index is more ob-vious;Finally,the calculation and design method of recycled aggregate filled steel tubular long columns under axial loading were proposed.%进行6根圆钢管再生混凝土长柱轴压的静力加载试验,观察试件受力的全过程和破坏形态,绘制出各试件的荷载-变形和荷载-应变关系曲线,分析长径比和套箍系数2个变化参数对试件变形和承载力的影响规律,采用国内外相关规程计算各试件的极限承载力并与实测值进行对比。结果表明:钢管再生混凝土轴压长柱受力过程经历了弹性阶段、弹塑性阶段和塑性下降阶段,均为弹塑性失稳破坏;长径比和套箍系数对钢管再生混凝土轴压长柱的受力性能均有影响,其中套箍系数影响较大;最后对于钢管再生混凝土长柱轴压的承载力计算及构件的设计提出建议。

  14. Experimental Study on Seismic Performance of Steel -reinforced Ultra-high-strength Concrete Column%钢骨超高强混凝土柱抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    郑林; 贾金青; 朱伟庆; 叶浩

    2014-01-01

    为研究钢骨超高强混凝土柱的抗震性能,对6根钢骨超高强混凝土柱(λ=2.6)在低周反复荷载下进行试验,并且分析了试件的破坏过程和破坏方式,以及轴压比、配箍率及型钢形式对延性的影响。试验结果表明:钢骨超高强混凝土柱主要破坏形态为弯曲破坏和弯剪破坏,发生弯曲破坏的试件荷载-位移滞回曲线饱满,下降段较为平缓,表现出良好的抗震性能,发生弯剪破坏的试件荷载-位移滞回曲线狭窄,下降迅速,抗震性能较差;配箍率高、轴压比小、配置 H 型钢试件抗震性能好。%To study the seismic performance of steel-reinforced ultra-high-strength concrete columns ,the test research of 6 steel-reinforced ultra-high-strength concrete columns (λ = 2 .6) subjected to low-cyclic repetitional loads was carried out .Then ,the specimens’ failure process and modes as well as the effects of the axial compression ratio ,reinforcement ratio and section steel shape on the ductility of the steel-reinforced ultra-high-strength concrete columns were discussed . The experimental results show that the main failure patterns of the specimens are bending failure and shear failure .The hysteretic curves of bending failure specimens are plump with relatively slow descending branches ,showing excellent seis-mic behavior .However ,the hysteretic curves of shear failure specimens are slim with relatively quick descending branch -es ,showing bad seismic behavior .The specimens with the high reinforcement ratio ,high axial compression ratio and H-shaped section steel show excellent seismic behavior .

  15. Analysis of lateral stability of I-section aluminum beams

    Institute of Scientific and Technical Information of China (English)

    CHENG Ming; SHI Yongjiu; WANG Yuanqing

    2006-01-01

    This paper focuses on the lateral buckling of laterally-unrestrained aluminum beams subjected to a concentrated, uniformly loading and pure-bending action. The design methods of lateral stability of aluminum beams in the current codes are discussed. The influence of material property on the lateral buckling of aluminum beams is investigated with finite element analysis (FEA) methods. Some numerical examples are given, and the results from current codes are compared with the FEA solutions. The design method on lateral stability of steel beams specified in the Chinese standard GB 50017-2003 is modified to calibrate the stability factors of aluminum beams according to the European code, British code, and American code, and the modified method is verified by FEA results. Through comparison with the available test results, the modified design method for overall stability of aluminum bending members is proposed in this paper and proved applicable in the design of lateral stability of aluminum beams.

  16. The Dissipative Column: A New Hysteretic Damper

    OpenAIRE

    Bruno Palazzo; Paolo Castaldo; Ivana Marino

    2015-01-01

    A new replaceable hysteretic damper to better control seismic building damage, consisting of two or more adjacent steel vertical elements connected to each other with continuous mild/low strength steel shear links, is proposed and investigated in this paper. New Dampers, called Dissipative Columns (DC), continuously linked with X-shaped steel plates, provide additional stiffness and damping to a lateral system by using a basic and minimally invasive construction element: the column. Working i...

  17. Experimental study on modified recycled aggregate concrete-filled steel tube columns under axial compression%改性钢管全再生粗骨料混凝土短柱的轴压试验

    Institute of Scientific and Technical Information of China (English)

    陈娟; 许成祥; 邓曦

    2015-01-01

    In order to make full use of recycled aggregate, 20 specimens with circular and square cross sections were designed to be tested, and the dosage of silica powder and content of steel fiber were regarded as the major variable parameters. Through the experiment, the entire compress process and failure modes of all specimens were observed, and load-strain curves of the specimens were obtained. The test results indicate that the ultimate axial load and corresponding strain of the concrete-filled steel tube columns would decrease after the replacement of natural coarse aggregate with 100% recycled coarse aggregate. The filling effect and pozzolanic action of silica powder and the confinement effect of steel fiber could be used to improve the performance of concrete-filled steel tube columns with 100% recycled coarse aggregate, and the performance of modified columns was i- dentical to that of common columns. The column with 10% cement replaced by silica powder and 1. 5%volume fraction of steel fiber has a higher ultimate axial load than that of common columns. In addition, the applicability of present theory and formula from different codes to calculate the bearing capacity of the specimens was obtained based on the comparison of calculated results. The results obtained by EC4 are more close to the experimental results.%为了最大化利用再生骨料,以硅粉和钢纤维掺量为主要变化参数设计了20个圆形和方形截面钢管全再生粗骨料混凝土短柱构件进行轴压试验,观察了短柱的受力全过程和破坏形态,获取了构件的荷载―变形全过程曲线,分析了硅粉和钢纤维掺量对其承载性能的影响,试验结果表明:混凝土中的粗骨料全部采用再生骨料会降低钢管再生混凝土柱的峰值承载力及峰值应变,可以采用硅粉的填充效应及活性和钢纤维对裂缝的内部约束来改善钢管全再生骨料混凝土柱的性能,经改性后的钢管全再生骨料混

  18. 抽柱门式刚架结构设计要点及对厂房经济性影响分析%Structure Design Points of the Steel Column-removed Portal Frame and Analysis of the Economic Impact on Plant Building

    Institute of Scientific and Technical Information of China (English)

    段潇川; 王小龙

    2016-01-01

    Taking the continuous multi-span and multi-slope portal frame as example,this paper analyzed the steel column-removed portal frame.Combined with China current code,the design methods and points of steel column-re-moved portal frame were illustrated.The steel quantity was compared between column-removed portal frame and none column-removed portal frame model.The conclusion was get that the structure form of steel column-removed portal frame is better than traditional none column-removed portal frame.%文章以连续多跨多坡门式刚架为算例,对抽柱门式刚架进行分析,提出了抽柱门式刚架的设计方法。结合我国现行规范对抽柱门式刚架的设计要点进行了说明,同时对比门式刚架中间抽柱和非抽柱模型的用钢量。得出结论:抽柱门式刚架结构形式优于传统非抽柱门刚。

  19. The type steel column concrete composite structure construction of Taiwan collaboration department international business square%台协国际商务广场型钢柱混凝土组合结构施工

    Institute of Scientific and Technical Information of China (English)

    殷有坤; 王定正

    2014-01-01

    Taking Taiwan collaboration department international business square as the project background, this paper analyzed the type steel col-umn structure of project main building, elaborated the key points of type steel column concrete composite structure construction, and researched the control measures of welding positioning reinforcement, stirrup making, lashing and other construction difficulty, in order to strictly control the construction quality, improved economic benefits.%以台协国际商务广场为工程依托,对工程主楼型钢柱结构进行了分析,阐述了型钢柱混凝土组合结构施工的要点,并对焊接定位钢筋、箍筋制作、绑扎等施工难点的控制措施作了研究,以严格控制施工质量,提高经济效益。

  20. Mechanism of concrete-filled double-skin steel tubular column subjected to compression torsion%圆中空夹层钢管混凝土压扭构件工作机理研究

    Institute of Scientific and Technical Information of China (English)

    黄宏; 范志杰; 陈梦成

    2013-01-01

    The working mechanism of concrete-filled double-skin steel tubular (CFDST) column under compression torsion is investigated. The compression torsion behavior of the concrete filled steel tube column was analyzed by the finite element software, and the calculated results were verified by the experimental results. The torque-angle relationship of the CFDST column subjected to compression torsion was calculated. The results indicate that the torque-angle curve can be divided into elastic, plastic and plastic hardening stages. Through the analyses of the three stages of torque-angle curve, the stress distribution of steel tubes and concrete, the interaction between the steel tubes and concrete, and the effects of axial compression ratio, it was show that when die axial compression ratio is low, the ultimate torque is increased with the axial compression ratio, and when the axial compression ratio is large, the ultimate torque is decreased with the axial compression ratio.%为了对圆中空夹层钢管混凝土构件在压、扭复合受力下的工作机理进行研究,采用大型通用有限元软件ABAQUS对圆实心钢管混凝土压、扭复合受力构件进行建模计算,现有的试验验证了计算结果与计算方法的正确性.再采用同样的方法对圆中空夹层钢管混凝土构件在压、扭复合受力状态下进行了模拟计算.通过计算发现,扭矩—转角全过程关系曲线分为弹性、弹塑性、塑性强化三阶段.通过对三个阶段扭矩—转角全过程关系曲线、内外钢管和混凝土的应力分布云图、三者间相互作用力以及轴压比影响的分析,结果表明,在加载过程中,当轴压比较小时,随着轴压比的增大,极限扭矩增加;当轴压比较大时,随着轴压比增大,极限扭矩降低.

  1. Study on Mechanical Properties of Damaged Axially Loaded Concrete Filled Steel Tube Columns Strengthened with CFRP Composite Materials%CFRP加固受损钢管混凝土轴压柱试验研究

    Institute of Scientific and Technical Information of China (English)

    顾威; 李宏男; 孙国帅

    2013-01-01

    Four damaged concrete filled steel tube columns strengthened with carbon fiber reinforced plastics (CFRP) and four contrast columns were tested. All specimens were notched in the central zone to simulate the loss of section due to corrosion. All specimens were axially loaded while strain and displacement were measured to demonstrate the effectiveness of this repair concept. Influences of the CFRP confinement and the aspect ratio on the load bearing capacity of the columns are analyzed. The test results show that within the scope of the test, CFRP would enhance the load bearing capacity of the damaged concentrically compressed concrete filled steel tube columns effectively; the increase rate of load bearing capacity due to CFRP decreases with the increase of aspect ratio. A calculating method is also presented, capable of predicting the axial load strength of concrete filled CFRP steel tube members. Experimental results are in good agreement with the predicted values.%采用4个受损轴压钢管混凝土柱试件和4个用碳纤维复合材料(carbon fiber reinforced plastics,CFRP)加固的受损轴压钢管混凝土试件进行对比试验研究,分析两者的受力机理,评价CFRP加固受损轴压钢管混凝土承载力提高效果.结果表明:由于CFRP的环向约束,受损钢管混凝土的钢管和核心混凝土的径向变形受到了限制,受损钢管混凝土轴压承载力有不同程度提高,且其提高效果随着长细比的增加而变小;提出了加固前后受损钢管混凝土承载力计算方法,其计算结果与试验结果吻合良好.

  2. Experimental study on ultimate bearing capacity of axially compressed high strength steel columns%高强钢焊接箱形柱轴心受压极限承载力试验研究

    Institute of Scientific and Technical Information of China (English)

    李国强; 王彦博,; 陈素文

    2012-01-01

    An experimental and theoretical study was presented on ultimate bearing capacity of axially compressed high strength steel columns. The experimental program included 7 welded box columns of 3 different cross sections which were welded with 11 mm-thick Q460 high strength steel plates made in China. The FEA models were built up according to measured sizes of members and tension coupon test results. And initial geometric imperfections and residual stress were taken into account in the FEA models. The experimental result shows that the stability coefficients of welded box columns of high strength steel are higher than the values of type c column curve in GB 50017--2003, and even higher than the values of type b curve for most of the specimens. However, due to the limited test result, the adoption of type b curve needs further verification. The FEA result agrees well with experimental result and could be a valid supplement of test data.%为了研究高强钢中厚板焊接箱形柱的极限承载力,以11 mm厚国产Q460高强钢中厚板制作了7个焊接箱形柱进行轴心受压试验。试件共包含宽厚比8、12、18三种截面,长细比分别为35、50、70。根据试件的实测尺寸、钢材的力学性能建立有限元模型,以初始缺陷的形式考虑了试件的初始挠度、初始偏心及焊接残余应力,分析预测了试件的极限承载力。试验结果表明,高强钢焊接箱形柱稳定系数采用GB 50017—2003《钢结构设计规范》中的c类截面柱子曲线偏保守,试验结果平均曲线更接近b类截面曲线,但仍需进一步验证。分析结果表明,考虑了初始缺陷的有限元模型可准确预测柱的极限承载力,可以作为试验数据的补充。

  3. 冷弯薄壁型钢拼合截面柱轴压承载力计算%Calculation Method for Bearing Capacity of Cold-formed Steel Built-up Columns Under Axial Compression

    Institute of Scientific and Technical Information of China (English)

    周绪红; 李喆; 刘永健; 石宇

    2012-01-01

    In order to investigate bearing capacity of cold-formed steel built-up columns under axial compression, authors used ANSYS finite element program to analyze the cold-formed steel built-up columns at home and abroad. Compared with experimental results, the validity of the finite element method (FEM) was verified. Furthermore, a detailed parametric study by FEM was carried out to mainly determine the influence of cross-section form, cross-section dimension and slenderness ratio of component for the built-up effect. The simplified calculation method to the bearing capacity of cold-formed steel built-up columns under axial compression was extracted. The analytical results show that with the increase of the slenderness ratio, the built-up effect improves. As for these columns connected with screws through web, when width-thickness ratio of flange is certain, with the increase of width-height ratio of cross-section, the integrity of the built-up web increases, which leads the built-up effect to strengthen. But the influences of different areas of cross-sections are not so obvious.%为了研究冷弯薄壁型钢拼合截面柱的轴压承载力,对各国有关冷弯薄壁型钢拼合截面柱的轴压试验进行了ANSYS有限元模拟分析,有限元计算结果与试验结果吻合良好,从而验证了有限元方法的正确性.采用有限元方法分析了构件截面形式、截面尺寸以及长细比对冷弯薄壁型钢拼合截面柱拼合效应的影响,提出了冷弯薄壁型钢拼合截面柱轴压承载力的简化计算方法.分析结果表明:随着长细比的增大,拼合截面柱的拼合效应随之增大.对于主要通过螺钉将腹板进行拼合的构件,当翼缘宽厚比一定时,随着截面宽高比的增大,腹板拼合的整体性增强,从而使拼合效应增大,而截面面积的改变对拼合效应的影响则不是很明显.

  4. 钢梁-圆钢管混凝土柱穿心连接抗震性能试验研究%Test study on seismic behavior of through beam connections of steel beams to circular concrete-filled steel tube columns

    Institute of Scientific and Technical Information of China (English)

    钱稼茹; 冯善文; 曹万林; 卢理杰

    2013-01-01

    为研究钢梁-圆钢管混凝土柱穿心连接的抗震性能,进行了3个大尺寸钢梁根部翼缘不处理的标准型、翼缘削弱型及翼缘扩大型节点试件的拟静力试验.试验结果表明:试件的破坏形态为钢梁根部坡口焊缝与钢管之间开裂,钢梁端部翼缘局部屈曲;钢梁悬臂端的极限位移角达0.04左右;钢梁固端弯矩-悬臂端转角滞回曲线饱满;翼缘削弱型试件的极限承载力为标准型试件的78%.建议在抗震设计的建筑工程中,钢梁-圆钢管混凝土柱可采用梁端部翼缘不处理的标准型穿心连接.%To study seismic behavior of through beam connections of steel beams to circular concrete-filled steel tube columns,quasi-static test of three large-scale joint specimens with different steel beam flange were conducted.The test results indicate that:the failure modes of specimens are fracturing between the groove welds at the end of beam flange and the steel tube,and are local buckling ofbeam flanges; for all three specimens,the ultimate rotation at the cantilever end of steel beam reaches 0.04 ; the hysteretic loops of the steel beam fixed end moment-cantilever end rotation are plump; the ultimate load-carrying capacity of the flange weakened type specimen is 78% of that of the standard type specimen.It is recommended to use the standard type through beam connections of steel beams to circular concrete-filled steel tube columns in the practice engineering projects.

  5. Seismic Behavior of Thin-Walled C Steel-Bamboo Plywood Composite Column%薄壁C型钢—竹胶板组合箱型柱抗震性能试验

    Institute of Scientific and Technical Information of China (English)

    蒋天元; 李玉顺; 单炜; 张王丽

    2011-01-01

    提出了一种新型的组合柱—以两块薄壁C型钢为基本骨架口对口拼接,在型钢腹板及翼缘处用结构胶黏剂黏结4块竹帘胶合板,形成截面形式为箱型的薄壁C型钢—竹胶板组合柱.以钢板厚度、长细比、轴压比等为基本参数,对5根组合柱进行了拟静力加载试验,观察组合柱在不同参数设置下的钢板、竹胶板的应变变化和荷载—位移滞回曲线,得到了组合柱的承载力指标和耗能系数、延性系数等抗震性能指标,在此基础上进行了组合柱的承载力计算方法分析.结果表明,长细比和钢板厚度对钢—竹组合柱加载初期的受力性能影响不明显,但影响柱子的后期极限承载力和刚度,而轴压比对组合柱的极限承载力和延性性能起着决定作用.根据钢—竹组合柱在弹性阶段的轴压力大小和应力—应变关系,提出了组合柱的力学简化模型及屈服承载力计算方法,其计算结果与试验值吻合较好.%The paper presents a new type of composite column composed by gluing four pieces of bamboo plywood on the surface of box columns and two pieces of thin-walled C steel spliced mouth to mouth in the core. Pseudo-static tests on a total of 5 composite columns were conducted in terms of steel sheet thickness, slenderness ratio and axial compression ratio of the columns. The bearing capacity, dissipative coefficient, ductility, and other indexes about seismic performance were ac quired by analyzing the changes of strain in the steel sheets and bamboo plates and the load-displacement hysteretic curves under different parameters. Result shows that slenderness ratio and steel sheet thickness have little effect on the mechanical behaviors of initial load, but have effect on ultimate strength and stiffness under load imposed in the late period. Axial compression ratio makes a great dif ?rence in bearing capability and ductility performances of these columns. Based on the measurement of

  6. SEISMIC PERFORMANCE RESEARCH ON BEAM-COLUMN SPLICE JOINTS OF PREFABRICATED STEEL FRAMED STRUCTURES WITH BRACES%斜撑对装配式钢框架梁柱拼接节点抗震性能影响研究

    Institute of Scientific and Technical Information of China (English)

    张爱林; 惠怡; 刘学春

    2014-01-01

    针对装配式钢框架带柱座梁柱拼接节点连接受力复杂、强度和刚度影响因素多等问题,应用非线性有限元软件ANSYS对带斜撑和无斜撑的两种节点进行数值模拟,研究斜撑对装配式钢框架梁柱节点的滞回性能、极限承载力、延性系数、破坏模式等抗震性能的影响。结果表明:斜撑的设置,可较大幅度地提高节点的刚度和承载力,对于螺栓型连接的梁柱节点,斜撑的设置使其承载力提高3倍多,焊接节点的承载力提高约50%,延性系数提高约70%;且有效地转移了塑性铰,使节点破坏位置位于斜撑之外的桁架梁上,起到保护节点的作用,符合“强节点,弱构件”的设计要求。同时反复荷载作用下的滞回曲线更加饱满,具有更好的抗震性能。%For column-beam splice joint with flange-column of fabricated steel structure ,the mechanical behavior and connection are very complex ,and there are many influencing factors for its strength and rigidity .ANSYS finite element analysis software was used to analyze and simulate the beam-column's joint of the steel framed structure with or without braces .The seism-resisting behavior of the fabricated steel frame beam-column joints including the hysteretic behavior,ultimate bearing capacity, ductility coefficient, failure mode etc.were studied.The results show that for the fabricated steel frame beam-column joints with supports the joint's rigidity and bearing capacity are increased greatly . To bolt connection of beam-column joints with braces , the bearing capacity is improved by more than three times , and to welded joint , it is improved by about 50 percent ,ductility factor is increased by about 70 percent .Through setting braces, the plastic hinge is transferred effectively , and the failure locations are located on the truss beam outside of the brace, which has played an important role in protecting the connection , and accorded

  7. Simplified calculation of rotational restraint stiffness for flange of cold-formed thin-walled C-shaped steel column%冷弯薄壁C形钢柱翼缘转动约束刚度简化计算

    Institute of Scientific and Technical Information of China (English)

    姚永红; 武振宇

    2013-01-01

    畸变屈曲是冷弯薄壁型钢构件的主要破坏模式之一,按翼缘模型计算其弹性畸变屈曲应力时需要确定腹板对翼缘的转动约束刚度.现有转动约束刚度计算公式较复杂,求解过程需要进行一次迭代.为了简化计算过程,提出了冷弯薄壁C形钢柱翼缘转动约束刚度简化计算方法.该方法在Lau和Hancock公式的基础上,结合我国《冷弯薄壁型钢结构技术规范》(GB50018-2002)中关于腹板和翼缘局部屈曲系数的规定而导出的,并根据Lau和Hancock公式计算结果对其进行了修正.与有限条分析值对比表明:该方法可以准确、方便地计算转动约束刚度,能够应用于冷弯薄壁型钢C形截面柱的设计计算.%The distortional buckling is one of the main failure modes for cold-formed thin-walled steel components. When the elastic distortional buckling stress of steel components is calculated with flange model, it is necessary to determine the rotational restraint stiffness provided by the web plate to the flange. However, the current calculation formula for the rotational restraint stiffness is complicated, and one iteration is required in the solution process. In order to simplify the calculation process, a simplified calculation method concerning the rotational restraint stiffness for the flange of cold-formed thin-walled C-shaped steel column was proposed. Based on Lau and Hancock' s formulas, the proposed method was derived in combination with the regulations concerning the local buckling coefficients of the web plate and flange in the Technical Code of Cold-Formed Thin-Walled Steel Structures (GB 50018-2002) in China, and it was then modified according to the results calculated by Lau and Hancock' s formulas. Compared with the finite strip analytical values, it is noted that the proposed method can calculate the rotational restraint stiffness accurately and conveniently, and can be used for the design and calculation of cold-formed thin

  8. Rapid Reinforcement of Masonry Structure without Constructional Columns Using Steel Component and Performance Study%钢结构快速加固无构造柱砌体方法号陛能研究

    Institute of Scientific and Technical Information of China (English)

    李响; 练剑峰; 戴卜云

    2011-01-01

    以实际工程背景为例,针对典型的有图梁无构造柱砌体结构教室在抗震方面的不足,提出一种钢结构快速加固形成类似构造柱体系的加固方法。从理论上比较此种加固方法与传统的新增钢筋混凝土构造柱的加固方法的加固性能,验证此种加固方法的有效性,最后提出在实际工程中的设计建议。%Based on practical engineering,considering classroom which have ring beams and no constructional the seismic deficiencies of typical masonry structural columns,a rapid steel structural reinforcement method is proposed which can form a similar system of constructional column.The strengthening performance of this method is compared with traditional reinforcement method of adding reinforced concrete constructional column theoretically to verify the effectiveness of this method.In the end, design suggestion for practical engineering is proposed.

  9. Column flotation

    Energy Technology Data Exchange (ETDEWEB)

    Kohmuench, J.N.; Norrgran, D.A.; Luttrell, E.; Luttrell, G.H. [Virginia Tech. (United States)

    2008-04-15

    Over the last decade, column flotation has been recognised in the industry to be most efficient and economical means of recovering fine coal while maximizing product grade. When designed properly, flotation columns provide a high combustible recovery while maintaining a low product ash. The paper looks at the benefits of using column flotation for fine coal recovery. 2 refs., 5 figs.

  10. 高强度钢柱高温下承载力数值计算方法%Numerical Method for Load Bearing Capacity of High Strength Steel Columns at Elevated Temperature

    Institute of Scientific and Technical Information of China (English)

    王卫永; 李国强

    2011-01-01

    In order to make fire resistance design of high strength steel columns in building structures, the numerical calculation method on load bearing capacity of high strength steel columns at elevated temperature was investigated. By taking the mechanical property of high strength steel at elevated temperature into consideration, extension was made on the inverse calculation segment length method and the program to compute the load bearing capacity of high strength steel columns at elevated temperature was performed. The program was adopted to compute the load bearing capacity. The results obtained by the program and the finite element analysis were compared and good agreement had been found. The influence of magnitude, distribution mode of residual stress and initial geometry imperfection on ultimate load bearing capacity was analyzed by employing the program. It is shown that the extended method can be is shown used to calculate the load bearing capacity of high strength steel columns at elevated temperature; the magnitude and distribution mode of residual stress had little influence but the geometry imperfection have significant influence on ultimate load bearing capacity.%为了对建筑结构中的高强度钢柱进行抗火设计和验算,研究了高强度钢柱在高温下的极限承载力数值计算方法.考虑温度对高强度钢材力学性能的影响,对常温下钢柱极限承载力计算的逆算单元长度法进行了延伸,编制了高温下高强度钢柱极限承载力计算程序.采用编制的程序对高强度钢柱在高温下的极限承载力进行了计算,将计算结果与有限元分析结果进行了比较,发现吻合较好.分析了高强度钢柱截面上残余应力的分布模式,残余应力大小和柱的初始几何缺陷对极限承载力的影响.研究表明:延伸的逆算单元长度法可以用于高强度钢柱高温下极限承载力计算,残余应力的分布模式和大小对高温下高强度钢柱的极限承载

  11. 方钢管高强混凝土柱的受力性能研究%RESEARCH ON MECHANICAL BEHAVIOR FOR HIGH STRENGTH CONCRETE-FILLED SQUARE STEEL TUBULAR COLUMNS

    Institute of Scientific and Technical Information of China (English)

    李斌; 高春彦

    2011-01-01

    Through the low cyclic load test of eight high strength concrete-filled square steel tubular columns, considering the effect of the axial compression ratio, steel ratio and slenderness ratio, the hysteretic curve, ductility, degradation of stiffness, energy dissipation capacity, failure mechanism and characteristics of the specimens were researched. The influence law of the axial compression ratio, steel ratio and slenderness ratio on the mechanical and seismic behavior of these columns were analyzed. The results indicate that the high concrete-filled square steel tubular columns have plump hysteretic loops, stronger energy dissipation capacity, and good ductility after the specimens reach ultimate loads, that the displacement ductility coefficient is between 3.05 and 4.07, and that the columns can meet the requirement of ductile specimens. The axial compression ratio has larger influence on the load-carrying capacity and the seismic behavior, with the increment of the axial compression ratio, the load-carrying capacity decreases, the displacement ductility and energy dissipation capacity reduces, and the stiffness degradation is faster; with the increment of steel ratio, the load-carrying capacity and elastic stage stiffness increase, and the displacement ductility and energy dissipation capacity increase; with the increment of the slenderness ratio, the load-carrying capacity and elastic stage stiffness reduce obviously.%该文以轴压比、含钢率和长细比为参数,进行了8根方钢管高强混凝土柱的低周反复荷载试验,研究分析了该类构件的滞回曲线、延性、刚度退化、耗能能力、破坏机理和特征;考察了轴压比、含钢率和长细比对试件受力性能及抗震性能的影响规律.研究表明,方钢管高强混凝土柱滞回曲线饱满,耗能能力强,达到极限荷载后具有良好的延性和较为稳定的后期承载能力,位移延性系数在3.05-4.07之间,满足延性构件的要求.柱轴压比

  12. 大比尺高含钢率型钢混凝土柱滞回性能试验%Experimental study on hysteretic properties of large-size SRC columns with high ratio of encased steel

    Institute of Scientific and Technical Information of China (English)

    殷小激; 吕西林; 卢文胜

    2012-01-01

    对8个含钢率分别为13.12%和15.04%的大比尺型钢混凝土柱进行水平低周反复加载试验,考察高含钢率型钢混凝土框架柱在反复荷载作用下的受力特点、破坏形态和变形特征。试件设计轴压比介于0.5~1.2之间,在压、弯、剪共同作用下发生弯曲型破坏。试验得到荷载一位移滞回曲线及型钢和钢筋的应变曲线,验证了型钢与混凝土的共同工作性能。试件滞回曲线具有良好的饱满性,每级滞回环大致重合,承载力没有发生明显退化,表明构件具有良好的耗能性能和抗震能力。根据平衡方程提出的承载力实用计算方法,可以相对准确的预测内置十字形带翼缘型钢的型钢混凝土柱正截面抗弯承载力。得到的截面M-N关系曲线可以为设计和进一步研究提供参考。%8 large-size SRC columns with 13.12% and 15.04% encased steel were tested under low-frequency cyclic lateral loading. The mechanical properties, failure modes and deformabilities are studied. The axial load ratios of the specimens range from 0.5 to 1.2. All the specimens showed flexure failures subject to combined axial force, bending moment and shear forces. Force-displacement hysteretic curves, strain curves of encased steels and rebars are obtained. The interaction behavior between encased steels and concrete are verified. The hysteretic curves of columns are plump in shapes. Hysteresis loops keep coincident under the same levels of lateral loads, and the bearing capacities does not change much, which indicate that the columns have good energy-dissipation performance and aseismic capacity. Based on the equilibrium equation, the suggested practical calculation method can accurately predict the bending-resistant capacities of SRC columns with encased cross-shaped section steels. The obtained M-N curves of cross-sections of SRC columns can be used as references tbr further studies.

  13. Experimental study on seismic behavior of recycled aggregate concrete filled square steel tube columns%方钢管再生混凝土柱抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    张继承; 吕行; 范启峰; 吴胜; 王静峰

    2016-01-01

    为研究方钢管再生混凝土柱的抗震性能,采用正交设计方法设计并制作了9个试件,并对其进行拟静力试验。考虑钢管壁厚、再生骨料取代率和轴压比3个变化参数,观察试件加载全过程和破坏形态,分析试件的滞回曲线、骨架曲线、延性、耗能性能和刚度退化。结果表明:方钢管再生混凝土柱试件破坏过程及破坏形态与普通钢管混凝土柱类似,主要表现为柱底钢管的鼓曲破坏;试件的滞回曲线均比较饱满,没有明显的捏缩现象,试件的变形性能良好;再生骨料取代率对钢管再生混凝土柱的位移延性系数影响较小,主要受钢管壁厚及轴压比的影响;加载完成后,各试件的等效黏滞阻尼系数达到0.2以上,表现出良好的耗能能力;试件刚度主要受钢管壁厚和轴压比的影响,再生骨料置换率对试件刚度的影响不大;三线型的P-Δ骨架曲线模型无量纲化后,试验数据有较好的规律。%To study the seismic behavior of recycled aggregate concrete filled steel tubular(RACFST)columns,nine specimens with different thickness of steel pipe,replacement rates of recycled coarse aggregate and axial compression ratios were tested under the cyclic reversed loading.The entire loading process and failure mode were observed,the hysteretic curve,skeleton curve,ductility,dissipation ca-pacity and stiffness degradation were analyzed.It is shown that the failure process and failure mode of RACFST columns are similar to those of concrete filled steel tubular columns,in which the circular steel tube at the bottom is buckled.All the hysteretic curves which have no obvious pinching phenomenon are plump,the stability and the deformation properties of the specimens is good.The influence of re-placement rate on displacement ductility coefficient is little,while thickness of steel pipe and axial compression ratios are mainly.The e-quivalent viscous damping

  14. 低周反复荷载作用下T形截面钢异形柱-钢梁节点抗震性能试验研究%Experimental research on seismic behavior of steel specially shaped column with T-shaped section to steel beam connections under cyclic loading

    Institute of Scientific and Technical Information of China (English)

    张爱林; 于劲; 李健; 刘会军

    2011-01-01

    以强震区多高层钢结构框架的梁柱边节点为研究对象,通过3个足尺T形截面钢异形柱-钢梁节点试件在低周反复荷载作用下的拟静力试验,研究了试件的变形、应变分布、破坏模态,得到了试件的滞回曲线、骨架曲线、承载能力、节点域的剪切变形、转动能力、延性性能、耗能能力等抗震性能指标,分析了节点域强弱对抗震性能指标的影响.试验结果表明,T形截面钢异形柱-钢梁节点在破坏前经历充分的塑性变形,其破坏模态为局部屈曲破坏,塑性铰出现于远离梁柱焊缝的梁截面上且发展充分,有较高且稳定的承载能力,具备较好的塑性转动能力、延性性能和耗能能力,能够在强震区使用.研究为此类节点的工程应用和钢异形柱结构技术规程的编制提供依据.%Quasi-static tests on three full-scale specially shaped columns with T-shaped section to steel beam connections were conducted under low cycle load reversals to study the behavior of exterior beam to column connections of multi-story or high rise buildings in high seismic regions. The deformation characteristics, strain distribution and the failure mode were investigated. The hysteretic loops, skeleton curves, bearing capacity, shear deformation of panel zone, rotation, ductility and energy-dissipation were obtained. The effect of the thickness of panel-zone was studied. Test results indicate that the steel specially shaped column with T-shaped section to steel beam connection has strong and stable bearing capacity, excellent plastic rotational performance, good ductility and energy-dissipation capacity. The typical failure mode is the local buckling with sufficient plastic deformation. The plastic hinge can be fully developed at the beam sections far away from the welds of the column-to-beam joint. Analysis result shows that steel specially shaped column with T-shaped section to steel beam connection can be used in regions of

  15. NONLINEAR ANALYSIS OF MULTI-CELL T-SHAPED CONCRETE-FILLED STEEL TUBULAR STUB COLUMNS%多室式钢管混凝土T形短柱的非线性分析

    Institute of Scientific and Technical Information of China (English)

    屠永清; 刘林林; 叶英华

    2012-01-01

    The confinement that the concrete core is subjected to in multi-cell T-shaped concrete-filled steel tubular (MT-CFST) columns is characterized by defining the equivalent square section and the angle of boundary between effectively confined area and ineffectively confined area of the concrete core. According to experimental results, the constitutive relationship of the concrete core is suggested by means of modifying the expressions of effective lateral pressure and the descending stage in Mander's confined concrete model. Numerical simulation of 8 MT-CFST stub columns under axial load is accomplished based on ABAQUS. The comparisons between calculated results and experimental data demonstrate that the suggested concrete constitutive relationship is applicable for the finite element analysis of MT-CFST columns. Subsequent discussion on the cooperative properties of two materials shows the similarity on mechanism between the MT-CFST columns and other types of CFST columns. Considering the MT-CFST columns as a combination of three rectangular concrete-filled steel tubular units with two extra steel plates removed, the formula for their bearing capacities is proposed based on superposition principle, which may provide some references for engineering practice.%通过定义等效方形截面和改变混凝土强约束区、弱约束区界线底角来衡量多室式T形截面内钢材对混凝土的整体约束作用,依据轴压试验结果修正了Mander约束混凝土模型中有效侧向约束力及下降段的表达式,建立了核心混凝土的本构关系。应用ABAQUS对8个多室式钢管混凝土T形短柱试件的轴压性能进行了模拟,模拟结果与试验数据的对比表明,该本构关系能较好地适用于对构件性能的非线性分析。在此基础上探讨了构件中钢材和混凝土的共同工作情况,发现其工作机理与其它截面形式的钢管混凝土柱较为一致。将多室式

  16. 不锈钢轴心受压构件稳定承载能力计算方法研究%NEW DESIGN METHOD FOR STAINLESS STEEL COLD-FORMED TUBULAR COLUMNS UNDER AXIAL LOAD

    Institute of Scientific and Technical Information of China (English)

    舒赣平; 郑宝锋; 沈晓明

    2012-01-01

    Test results of the stainless steel material property indicate that: considerable difference exists among different states of the same type stainless steel and also exists among varieties of type. However this difference is not directly considered in the typical design codes existing in the world. Based on the verified FEM model, total 30 column curves are calculated that covered the range of material properties in common use. The concept of modification slenderness ratio is utilized to modify the Perry formula and the K&R formula; at last, new design formula is obtained for calculating the buckling strength of stainless steel columns. Comparisons between the available test resuh and the proposed approach are conducted. The comparisons indicated that the proposed approach could fit the test results well. This approach could be used as a reference for the first version of stainless steel design code of China.%国内外不锈钢材料力学性能的试验资料表明:不同牌号不锈钢材料的力学性能差别较大;同牌号不锈钢材料的力学性能也有一定差别,而材料力学性能变化对轴心受压不锈钢柱的稳定性系数的影响在国外典型不锈钢结构设计规范中均无明确的规定。基于经验证的有限元模型,计算了30种典型不锈钢材料的稳定系数曲线,采用修正正则化长细比概念对Perry公式及K&R公式进行改进,得到适用于常用不锈钢材料力学性能的轴心受压柱稳定系数表达式,并与国内外已有的试验数据进行对比,结果表明,此表达式具有较高的精度,可供我国不锈钢结构设计规程中轴心受压构件设计条文编制参考。

  17. Bearing capacity of thin-walled steel tube short columns filled with lightweight aggregate concrete under axial load%薄壁钢管轻骨料混凝土轴压短柱承载力分析

    Institute of Scientific and Technical Information of China (English)

    肖海兵; 赵均海; 孙楚平; 彭宁; 孙珊珊

    2012-01-01

    Based on the unified strength theory, considering the effects of the intermediate principal stress and the differences of the multi-axial strength criterion for the lightweight aggregate concrete and common concrete, by introducing parameter αu and/βu, loop tensile stress σθ , longitudinal compressive stress σ, and radial compressiye stress σ of the thin- walled steel tube in ultimate bearing condition were obtained. Thus the calculation formula of ultimate bearing capacity of thin-walled steel tube short columns filled with lightweight aggregate concrete was deduced, and the influence complication was analyzed. Compared with the obtained solution and the test results in reference, good agreement can be found. The results indicate that the unified strength theory has the good applicability in the calculation of ultimate bearing capacity of thin-walled steel tube short columns filled with lightweight aggregate concrete. The results can provide theoretical foundation for the design of thin-walled steel tube filled with lightweight aggregate concrete.%运用统一强度理论,考虑中间主应力的影响,引入参数αu,βu确定薄壁钢管在极限荷载时的环向拉应力σθ、纵向压应力σz和径向压应力σr,并考虑轻骨料混凝土与普通混凝土多轴强度准则差异的影响,推导出薄壁钢管轻骨料混凝土轴压短柱的极限承载力公式,并对影响因素进行了分析。将本文计算结果与文献试验数据进行比较,结果吻合良好,表明将统一强度理论运用于薄壁钢管轻骨料混凝土轴压短柱承载力计算是可行的。该结果为薄壁钢管轻骨料混凝土的优化设计提供了一定的理论依据。

  18. 型钢混凝土梁-角钢混凝土柱框架抗震性能试验研究%Study of seismic performance of frame structures of steel reinforced concrete beams and angle-steel concrete columns

    Institute of Scientific and Technical Information of China (English)

    郑文忠; 王琨

    2011-01-01

    This paper presents an experimental and theoretical study of two frame structures of steel reinforced concrete beams and angle-steel concrete columns under horizontal low cyclic loading, respectively. Based on the test results, the hysteretic curves for the horizontal load-displacement and the failure modes are obtained. The hysteretic behavior, skeleton curve, stiffness degradation, energy dissipation, and residual deformation of the two frames are studied. The nonlinear structural analysis program OpenSees is employed to calculate the hysteretic curves. The influences of slenderness ratio, axial compression ratio, steel ratio of column, cross-section moment resistance of the beam, ratio of steel bars and prestressing level on the skeleton curves are studied. The results indicate that this type of frame performs well if under earthquake.%完成两榀型钢混凝土梁-角钢混凝土柱框架水平低周反复荷载试验,考察这类框架的滞回特性、骨架曲线、刚度退化、耗能能力、残余变形、破坏形态等抗震性能,并采用OpenSees软件对两榀框架进行滞回模拟分析.考察柱长细比、轴压比、柱含钢率、梁内型钢截面抵抗矩、梁配筋率及预应力度等参数对框架骨架曲线的影响.研究结果表明,此类框架具有优良的抗震性能,为其在抗震区的推广使用提供了参考依据.

  19. Experimental study on restoring force characteristics of steel column base with wedge device%带楔块装置钢柱脚恢复力特性试验

    Institute of Scientific and Technical Information of China (English)

    雷劲松; 姚勇; 卢学松; 高松隆夫; 邹银生

    2011-01-01

    A new isolation device was designed to avoid damage of steel exposed-column base in earthquake,which consists of a wedge compressed by a spring and a counter-wedge.By the plastic elongation of the anchor bolt,the deformation of the spring and the slip of the wedge,the device can effectively dissipate the earthquake energy and control the damage of the structure.Dynamic cyclic test was performed to study the hysteretic behaviors of steel exposed-column base with and without the device.The results show that the ordinary column base is observed to be slip-type due to a gap between the nut of the anchor bolt and the base plate,caused by the plastic elongation of the anchor bolt.The new isolation column base is observed to be non-slip-type due to the gap which can be eliminated by use of the new device.Based on test results,a new non-slip-type hysteretic model is proposed.The results show that this device provides a better seismic performance and can be used conveniently.%为避免钢结构露出型柱脚在地震中发生破坏,研究一种新的减震装置。该装置通过楔块滑动、弹簧变形和螺杆的塑性伸长来控制柱脚位移,同时消耗地震能量,达到消能减震的效果。采用方形空心钢管柱,分别对普通螺栓柱脚和带减震装置的柱脚进行低周往复加载试验,研究其恢复力特性。试验表明:普通螺栓连接的柱脚呈滑移型滞回特征;由于弹簧恢复和楔块切入,新型柱脚连接每次加载卸载均以原点为始终,呈无滑移型滞回特征。根据试验结果,得到了带楔块装置钢柱脚的无滑移型恢复力模型。研究结果表明,无滑移型减震连接的钢柱脚具有良好的抗震性能且简单易用

  20. Experimental Study and Nonlinear FEM Analysis on Seismic Performance of CFRP Steel Tube Composite Columns Filled with Steel Reinforced Concrete%碳纤维钢骨-钢管混凝土柱抗震性能试验与有限元分析

    Institute of Scientific and Technical Information of China (English)

    徐亚丰; 王越

    2013-01-01

    In order to research the mechanical properties of carbon fiber steel tube composite columns filled with steel reinforced concrete under low frequency cyclic loads to provide a reference for practical engineering application,3 specimens of different axial compression ratio are on the pseudo-static test and load displacement component hysteretic curve,skeleton curve,ductility coefficient of mechanics performance is analyzed.At the same time,the large-scale general finite element analysis software ABAQUS is adopted to the numerical analysis and experimental verification of hysteretic performance of carbon fiber reinforced concrete filled steel tube columns.The simulation results of carbon fiber steel tube composite columns filled with steel reinforced concrete are in good agreement with experimental results.No matter how to change axial compression ratio,load-displacement hysteretic curves graphics has good stability and curve graph are plump spindle or arched without significant pinch phenomenon.It shows that the plastic deformation ability of the components is strong.As the axial compression ratio increases,the skeleton curve appears obvious decline and the ultimate bearing capacity of the component reduces and extreme value point corresponding to the displacement is smaller.Limit load and limit displacement and ductility coefficient decreases with the increasing of axial compression ratio.The carbon fiber steel tube composite columns fiiled with steel reinforced concrete has good ductility,good seismic performance,adaptation combined with practical engineering applications.%目的 研究碳纤维钢骨-钢管混凝土柱在低周往复荷载作用下的力学性能,为实际工程应用提供参考.方法 制作了3个试件并对其进行拟静力试验,分析不同轴压比下构件的荷载-位移滞回曲线、骨架曲线、延性系数等力学性能.同时采用ABAQUS对碳纤维钢骨-钢管混凝土柱的滞回性能进行了数值分析及试验

  1. Design and implementation of automatic welding system for column-wing-type radiators of steel combined with aluminum%钢铝复合柱翼型散热器自动焊接系统设计与实现

    Institute of Scientific and Technical Information of China (English)

    张冠; 赵冬梅; 梁楚华

    2014-01-01

    为实现钢铝复合柱翼型散热器连续自动焊接,设计了一种基于工业PC机和运动控制卡的多轴联动控制系统。上位机软件实时调用PCI1040运动控制卡自身函数并接收传感器、限位开关的反馈信号来规划并控制焊接动作。为解决顺序焊接过程中焊接变形累积问题,该控制系统新增了位置检测模块。实验证明,该专用自动焊接系统在进行钢铝复合柱翼型散热器焊接过程中能够持续稳定可靠地焊接,达到了良好的焊接效果。%To achieve continuous automatic welding of column-wing-type radiators of steel combined with aluminum ,a multi-axis control system is designed based on IPC and motion control card .PC software can call the function of motion control card PCI1040 real-time and receive feedback signals of the sensors ,and limit switches for the plan and control of welding .The control system adds a position detection module to solve the problem of welding deformation accumulation during welding process in succession .Experimental results prove that the special automatic welding system can satisfy the welding of column-wing-type radiators of steel combined with aluminum steadily and reliably ,achieving a good welding effect .

  2. 热成型不锈钢圆管混凝土轴压短柱受力性能试验研究%Experimental study on axial compressive behavior of concrete-filled thermoforming stainless steel tubular stub columns

    Institute of Scientific and Technical Information of China (English)

    陈誉; 李凤霞; 王江

    2013-01-01

    This paper presents an experimental study on axial compressive behavior of concrete-filled thermoforming stainless steel tubular ( CFTSST) stub columns. Seventeen specimens of CFTSST stub columns with different parameters were tested under axial compression. The parameters in the study included the compressive strength of concrete ( C30 and C40) ,wall thickness of thermoforming stainless steel t (0. 9 mm,l. 0 mm,l. 2 mm) and height-diameter ratio of specimens A (3.0, 3.5 and 4.0). This paper presents test procedure, specimens failure phenomena, load-axial displacement curves, load-circular strain curves and load-axial strain curves. Based on the failure phenomena, all specimens were divided into 5 failure modes. The effects of t and A on compressive ultimate capacity, ductility and stiffness were investigated. The results of tests show that the stress of specimens increases greatly at the end of the yield stage; as value of t increases, compressive ultimate capacity, ductility and stiffness of specimens increase; as value of A increases, ductility increases, stiffness decreases; the value of compressive ultimate capacity gets maximum when the value of λ is 3. 5, it is lower when A is 4. 0,gets minimum when A is 3. 0; according to the comparisons between CFTSS tubular stub columns and concrete-filled steel tubular stub columns, the results show that the restraint amplification coefficient of CFTSS tubular stub columns is higher.%对热成型不锈钢圆管混凝土短柱在轴向压力作用下的承载性能进行试验研究,试验主要参数为混凝土强度(C30和C40)、不锈钢管壁厚t(0.9 mm、1.0 mm和1.2mm)和试件的高径比λ(3.0、3.5、4.0),试验观测了不锈钢圆管混凝土短柱在轴向压力作用下的破坏现象、试件荷载-轴向变形曲线、荷载-环向应变曲线、荷载-轴向应变曲线等.根据试验的破坏现象,将试件分为5种破坏模式,并分析了不锈钢管壁厚t和试件的高径比λ对试件的承载

  3. Seismic performance comparison of steel frames with improved beam-column connections%改进型节点钢框架整体模型的抗震性能对比分析

    Institute of Scientific and Technical Information of China (English)

    张艳霞; 王宗洋; 宁广; 李佳睿

    2016-01-01

    Based on the experiment and finite element analyses on some improved connections,including the reduced beam flange connection,widened beam flange connection and widened-reduced beam flange connection,the finite element models of three steel frames with these connections as well as the rigid frame were built by using ABAQUS software.The modal analysis and the dynamic time-history analysis of the steel frames were carried out to compare their seismic behaviors with that of the rigid frame.The analysis results indicate that in the three improved steel frames,the plastic hinge could be shifted away from the panel zone to protect the welded seam at the beam end under a 8-degree rare earthquake.Compared with the reduced-beam flange steel frame,the widened-reduced beam flange steel frame can control more effectively the story drift.Compared with the widened-beam flange steel frame,the widened-reduced beam flange steel frame has less influence on the base shear force and leads to the smaller development of plastic strain in the column base and panel zone.Therefore,the widened-reduced beam flange steel frame has better seismic behavior.%针对钢框架梁柱加宽型节点、削弱型节点和加宽-削弱型节点,在已经完成了三种改进型梁柱节点试验与有限元分析的基础上,采用 ABAQUS 有限元软件建立了8层三种改进型节点框架和普通刚接框架模型,对其进行模态和8度罕遇地震作用下的动力时程分析,并详细对比分析四种钢框架的抗震性能。分析结果表明:与刚接框架相比,三种改进型节点框架在8度罕遇地震下实现了节点塑性铰外移,保护了梁端焊缝。与节点削弱型框架相比,节点加宽-削弱型框架有效的控制了结构的层间位移角;与节点加宽型框架相比,节点加宽-削弱型框架对结构基底剪力影响不大,柱脚和节点域塑性应变小于节点加宽型框架,因此具有更为可靠的抗震性能。

  4. 利用钢铁盐酸酸洗废液在填料塔中制备FeCl3%Preparation of FeCl3 from Steel Pickling Waste Liquor in Packed Column

    Institute of Scientific and Technical Information of China (English)

    肖娟宜; 丁德才; 王权永; 尹平河

    2013-01-01

    以钢铁盐酸酸洗废液为原料,亚硝酸钠为催化剂,氧气为氧化剂,在填料塔中催化氧化制备三氯化铁.考察了反应温度、催化剂加入量和添加方式、循环流量等对制备三氯化铁的影响.实验结果表明,在优化的工艺条件为料液预热温度为60℃、催化剂加入量为钢铁盐酸酸洗废液总质量的0.30%、料液循环流量6.0 m3/h的条件下,反应80~120 min,酸洗废液中的Fe2+完全氧化为Fe3+.%FeCl3 was prepared by catalytic oxidation in a packed column using steel pickling waste liquor as raw material,sodium nitrite as catalyst,oxygen as oxidant.The effects of reaction temperature,catalyst dosage and adding method,and circulation flow rate on FeCl3 preparation were investigated.The experimental results show that under the conditions of feed solution preheating temperature 60 ℃,catalyst dosage 0.3% of steel pickling waste liquor mass,feed solution circulation flow rate 6.0 m3/h and reaction time 80-120 min,Fe2+ in steel pickling waste liquor can be oxidized to Fe3+ completly.

  5. Research on calculation of length coefficients of no-sway buckling semi-rigid steel frame column%无侧移失稳半刚接钢框架柱计算长度系数研究

    Institute of Scientific and Technical Information of China (English)

    宋玉宝; 高毛毛

    2011-01-01

    According to the forms of beam no-sway buckling,the paper adopts the semi-rigid spiral spring simulation nodes,considers the mutual influence when the node semi-rigid features and the various stiffness of the nodes of the column's two sides,leads the connection relative flexibility u and the partition coefficient of relative angle of beam columns α,and concludes the calculation formula for the stiff correction coefficient of beam lines β,and indicates the formula for the calculation of length of the semi-rigid steel frame columns.%按照梁无侧移失稳形式,采用螺旋弹簧模拟节点的半刚性,考虑了节点半刚性及柱两侧节点刚度不同时的相互影响,引入了连接相对柔度u和梁柱相对转角的分配系数α,得到了横梁线刚度修正系数β的计算公式,进而得到了半刚接钢框架柱的计算长度系数公式。

  6. 方钢管混凝土压弯构件滞回性能的试验研究%Tests of hysteresis behaviors of concrete filled steel tubular beam-columns with square sections

    Institute of Scientific and Technical Information of China (English)

    陶忠; 韩林海

    2001-01-01

    以轴压比和含钢率为试验参数,进行了7个方钢管混凝土压弯构件在往复荷载作用下的荷载-位移滞回性能的试验研究,所得滞回曲线的图形都具有较好的饱满性,没有明显的捏缩现象,且和数值计算结果吻合良好。还利用已有的恢复力模型对构件进行了滞回曲线的理论计算,并和试验结果进行了分析对比,结果表明二者基本吻合。%Seven concrete filled steel tubular beam-columns with squaresections subjected to cyclic lateral loads are introduced in the paper. The test results show that the hysteretic curves of the beam-columns are plump in shapes, and have no significant pinch phenomenon. The tested curves are in good agreement with those of numerical calculation. Finally, a kind of restoring force model is applied to predict the load-deformation hysteretic curves.

  7. 配置核心钢管的钢筋混凝土柱-钢骨混凝土梁组合框架抗震性能试验研究%Test on seismic performance of frame structure of steel reinforced concrete beam and steel-tube encased concrete column

    Institute of Scientific and Technical Information of China (English)

    王琨; 袁沈峰; 曹大富; 陈再现

    2013-01-01

    This paper conducted a test on two frame structures of steel reinforced concrete beam and steel-tube encased concrete column under horizontal low cyclic loading.The test process and failure mode were observed,and the hysteretic behavior,skeleton curves,stiffness degradation,energy dissipation,and residential deformation of the two frames were studied.Meanwhile,the law of strain values of longitudinal bars,flanges and steel-tube in the beam and column end was analyzed carefully,and the order of plastic hinges was given.The test results show that hysteretic curves of the two specimens are plump,and one also behaves good energy dissipation when it is prestressed,and they behave good seismic performance.Meanwhile,the hoop strains of steel-tube of plastic hinge in the column bottom changes unevenly during the whole loading,and they could supply effective constraint on compressive concrete.And the cracks could be delayed when the steel reinforced concrete beam is prestressed.Furthermore,the sequence of plastic hinges of the two specimens is ‘ beam ends before and column bottoms after',so that the mechanism of energy dissipation for beam plastic hinges and a delayed occurring of plastic hinges for column bottom could be achieved.%进行两榀配置核心钢管的钢筋混凝土柱-钢骨混凝土梁组合框架试件在水平低周往复荷载作用下的试验研究,观察试验过程及破坏形态,研究试件的滞回特性、骨架曲线、刚度退化、耗能能力、残余变形等抗震性能,同时对梁柱端纵筋、钢骨翼缘及钢管在不同加载位移下的应变变化规律进行分析,得到框架结构的出铰顺序.研究结果表明:两榀框架滞回曲线饱满,施加预应力后仍具有较好的耗能能力和延性,表现出良好的抗震性能;框架柱底塑性铰区的钢管环向应变在整个加载过程中呈不均匀变化趋势,截面受压区钢管环向受拉,能够对受压区混凝土提供有效

  8. 不锈钢冷成型管截面轴心受压构件的有限元分析%FINITE ELEMENT ANALYSIS OF STAINLESS STEEL COLD-FORMED TUBULAR COLUMNS UNDER AXIAL LOAD

    Institute of Scientific and Technical Information of China (English)

    郑宝锋; 舒赣平; 沈晓明

    2012-01-01

    ANSYS is employed to study the overall buckling properties of stainless steel cold formed tubular columns under axial load. Non-linear property of material, the effect of cold-formed, local and overall imperfection as well as the residual stress are considered in this model. The comparisons between test results and the calculated results are performed in order to verify the FEM model. Comparisons indicate that the developed FEM model could represent the test exactly and the deviations in average are limited in 5%. Then the influences of varieties of factor are valued. The results of parameterized analysis conclude that: the influence of the increase strength in the corner region, the parameters variation of the material property and the amplitude of the overall imperfection could cause considerable changes in the buckling strength of stainless columns; shifts in section types almost do not influence the buckling strength. The conclusion could be regarded as the foundation of the design method for cold-formed stainless steel columns.%采用有限元软件ANSYS对不锈钢冷成型管截面轴心受压长柱进行模拟,有限元模型中考虑不锈钢材料的非线性本构关系、冷加工效应、构件的初始缺陷以及构件中的残余应力。将模拟结果与国内外的试验数据进行对比。对比表明:有限元模型能够准确地模拟不锈钢构件的受力全过程,模拟平均误差小于5%;对影响不锈钢轴心受压构件受力性能的因素进行分析,分析表明:方矩管截面的转角区冷加工效应,不锈钢材料力学性能参数变化以及构件的整体缺陷取值对构件的整体稳定性能影响较大,而不锈钢构件的截面对稳定系数影响很小。分析结论可作为建立不锈钢轴心受压构件稳定承载力设计公式的参考。

  9. Experimental research on seismic behavior of steel reinforced high strength concrete frame columns%型钢高强混凝土框架柱抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    郑山锁; 张亮; 李磊; 胡义; 胡长明

    2012-01-01

    基于16个型钢高强混凝土(SRHSC)框架柱试件的低周反复加载试验,对其抗震性能进行了研究。试件设计参数为剪跨比、轴压比、混凝土强度、含钢率和配箍率。对不同设计参数试件的受力特点、破坏形态、滞回性能、骨架曲线、耗能能力、位移延性等主要抗震性能指标进行了分析,得到了试件耗能指标、位移延性与诸设计参数之间的关系曲线。试验结果表明:试件荷载-位移滞回曲线饱满,下降段较为平缓,其他各项抗震性能指标较为优异,总体上表现出良好的抗震性能;混凝土强度等级超过C100的SRHSC框架柱的承载力优势明显,但由于高强混凝土的脆性导致其耗能能力及延性较普通型钢混凝土框架柱稍差;试件剪跨比、含钢率以及配箍率的提高能够增强其抗震性能,而混凝土强度、轴压比的提高将降低其抗震性能。%The seismic behavior of steel reinforced high strength concrete (SRHSC) frame columns was investigated by the experiments of 16 frame column specimens subjected to a constant axial load and cyclic lateral loads. The design parameters of specimens included shear span ratio, axial compression ratio, concrete strength, steel ratio and stirrup ratio. The study focused on main seismic performance indexes of specimens which had different design parameters, such as mechanical characteristics, failure mode, hysteretic behavior, energy dissipation and ductility. The influences of design parameters on energy dissipating capacity and ductility were analyzed. The results show that the hysteretic curves of specimens are plump with relatively slow descending branches. Some other seismic performance indexes are good, indicating excellent seismic behavior. The bearing capacity of SRHSC frame columns is excellent, but the ductility and energy dissipation ability are inferior to those of ordinary steel reinforced concrete structures. With the increase of

  10. Experimental study on slip behavior between shaped steel and concrete in SRC columns under cyclic reversed loading%低周反复荷载下型钢混凝土柱滑移性能试验研究

    Institute of Scientific and Technical Information of China (English)

    李俊华; 薛建阳; 赵鸿铁

    2008-01-01

    通过在型钢翼缘外侧滑移传感器,对轴力和反复水平荷载作用下型钢混凝土柱的粘结滑移性能进行了试验研究.试验中主要考虑了跨比、轴压比、配箍率、混凝土强度的影响.由试验得到了水平荷载-滑移滞回曲线和骨架曲线、滑移沿柱高的分布规律等.试验结果表明,型钢混凝土的荷载-滑移滞回曲线比较丰满,在整个加载过程中没有明显的"捏拢"现象;滑移沿柱高大致呈指数分布,柱根位置的滑移量最大,由柱根向柱顶逐渐递减;当剪跨比小于2时,滑移随剪跨比的增大而减小,当剪跨比大于2以后,滑移又随剪跨比的增大而增大;滑移随着轴压比的增大增大,随着配箍率和混凝土强度的提高而减小;随着荷载循环次数的增加,滑移刚度不断减小,滑移量不断增大,出现明显的粘结退化现象.%Slip distribution behavior of SRC (steel reinforced concrete) columns under constant axial load together with cyclic reversed horizontal load is studied by embedding slip transfers on the flanges of shaped steel. Four test parameters,i. e., shear span ratio, axial compression ratio, stirrup ratio and volumetric ratio and concrete strength are taken into consideration- Hysteretic and skeleton curves of slip against horizontal load as well as slip distribution law along columns are obtained from tests. Test results show that the hysteretic curve of slip against horizontal load is chubbiness and fold phenomenon does not occur in the course of loading. The interior slip between shaped steel and concrete is exponentially distributed along the columns. Maximum slips lie in the bottom of columns, and gradually descend from bottom to top. Slip increases with the increase of axial compression ratio, but decrease with the increase of stirrup ratio or concrete strength.When the shear span ratio is less than 2. 0, slip decreases with the increase of shear span ratio, but when shear span ratio exceeds 2

  11. Experimental study on the mechanical behavior of lightweight concrete filled steel tubular short columns after fire%轻骨料钢管混凝土短柱受火后力学性能的试验研究

    Institute of Scientific and Technical Information of China (English)

    王新堂; 周明; 王万祯; 仇心金

    2011-01-01

    Ceramsite concrete filled steel tube (CCFST) has not only the advantage of lightweight, but also good ductility that the ordinary concrete-filled steel tube structure has. However, study on the performance of CCFST structure after fire is still on the exploration stage. The mechanical behavior of twelve unprotected short columns of CCFST after fire was experimentally investigated. Effects of the parameters, such as the maximum value of fire temperature, fire duration, and slenderness ratio of the specimen and steel proportion on the strength and ductility of CCFST were discussed. The test results show that the CCFST short columns after fire had higher bearing capacity and better ductility, there was no descent segment in the load-displacement curves for most of the specimens after fire, and the bearing load increased again after the descent segment. It was concluded that effect of the maximum value of fire temperature and fire duration on the behavior of CCFST short columns after fire is related to geometrical parameters, and the degree of variation of the maximum value of fire temperature on the bearing capacity of the CCFST short columns increase with the slenderness ratio of the specimen.%钢管陶粒混凝土不仅具有陶粒混凝土轻质的特点,也拥有一般钢管混凝土结构的良好延性,但日的对火灾后钢管陶粒混凝土结构的性能还缺乏研究。通过对3组12根钢管陶粒混凝土短柱受火后力学性能的对比试验研究,讨论小同参数的钢管陶粒混凝土短柱受火后的剩余承载力和破坏形态的变化,重点讨论火灾最高保持温度、最高炉温持续时问、试件长细比、含钢率等参数对钢管陶粒混凝土短柱承载力和延性的影响。试验结果表明,钢管陶卡证混凝土短柱受火后仍然具有较高的承载力和良好的延性,火灾后多数试件的荷载一位移曲线并没有出现下降段,甚至出现承载力部分下降后又重新上升

  12. Quasi-static experimental study of outer diaphragm connections between square concrete filled steel tube columns and steel beams%方钢管混凝土柱-钢梁外隔板节点拟静力试验研究

    Institute of Scientific and Technical Information of China (English)

    黄炳生; 杜培源; 黄顾忠

    2012-01-01

    Through quasi-static tests on two outer diaphragm connections between square concrete filled steel tube columns and H shape steel beams, the hysteretic behavior, energy dissipation capacity, ductility, stress distribution and force transfer mechanism of the joints under low cycle reversed loads are studied. The results indicate that such joints have higher carrying capacity, better ductility and energy dissipation behaviors. Some of the end moments of the beams were transferred to the column web and the core concrete at the panel zone by the outer diaphragm connected to the column web. Other end moments were directly transferred to the column flange and the core concrete by the diaphragm near the column corner. Serious stress concentration occurred in the diaphragm near the column corner. Nonlinear FEM models of the outer diaphragm connection between concrete-filled square tubular columns and steel beams involving large deformation and material nonlinearity are presented. Joint behaviors and stress distributions were analyzed. The results indicate that the load-displacement curves, stress distribution from the FEM agree well with framework curves of the cyclic behavior from the low-cycle reversed loading tests.%通过对2个方钢管混凝土柱一工字钢梁外隔板式节点试件进行的拟静力加载试验,研究节点在反复循环荷载作用下的滞回性能、耗能能力、延性、应力分布和传力机制。试验结果表明,节点具有较高的承载力以及较好的延性和耗能能力,外隔板式节点的粱端弯矩一部分通过柱腹板两侧隔板传递到柱钢管腹板和核心混凝土,另一部分则主要通过柱角两内侧各0.25倍柱宽范吲内的隔板直接传递给柱钢管翼缘和核心混凝土。柱角附近的隔板出现严重的应力集中,影响节点的耗能和延性。埘节点建立同时考虑几何非线性和材料非线性的有限元分析模型,模拟分析了节点的受力性能。结

  13. Experimental study on hysteretic behavior of high strength steel box-section columns%高强度钢材箱形柱滞回性能试验研究

    Institute of Scientific and Technical Information of China (English)

    施刚; 邓椿森; 班慧勇; 陈以一; 王元清; 石永久

    2012-01-01

    为研究Q460高强度钢材箱形柱的抗震性能,对5个足尺试件进行了水平往复加载试验研究,分析了板件宽厚比、轴压比等因素对试件的承载力、破坏模式、耗能能力、变形能力和延性的影响。试验结果表明,Q460高强度钢材箱形柱具有很好的耗能能力和抗震性能,适用于抗震钢框架;除试件HB-1外其他试件本身及其柱脚节点均未发生焊缝开裂,证明设计合理、质量合格的Q460高强度钢材焊缝连接具有足够的承载力和良好的抗震性能;板件宽厚比越大,试件局部屈曲出现得越早,最大荷载对应的位移级越小,达到破坏时的位移级也越小;试件发生局部屈曲的范围及屈曲中心位置相对于试件截面高度的比值依次减小,所有试件最大屈曲位置距固定端0.25B~0.50B(B为等边箱型截面外边长),塑性区范围距离固定端0.72B~1.06B。根据试验结果,建议在轴压比不大于0.2时,Q460钢材箱形截面压弯构件板件宽厚比限值不应大于30;同时,钢框架柱在进行抗震设计时,其板件宽厚比限值应与轴压比相联系,轴压比越大,板件宽厚比限值应越小。%In order to study the seismic behavior of Q460 high strength steel box-section columns, 5 full-scale specimens were tested under cyclic loading. The influences of the width-to-thickness ratio and axial-load ratio on the load carring capacity, failure modes, energy dissipation capacity, deformation capacity and ductility were analyzed. The test results indicate that Q460 high strength steel box-section columns have excellent energy dissipation capacity and seismic behavior and are applicable for seismic steel frames. No welds of the specimens or the column bases exceptspecimen HB-1 crack, which proves that Q460 high strength steel welds by reasonable design and qualified quality have enough load carrying capacity and seismic behavior. With higher plate width-to-thickness ratio, local buckling occurs

  14. 损伤型钢混凝土异形柱框架抗震性能试验研究%Experimental study on seismic behaviors of damaged steel reinforced concrete frame with special-shaped columns

    Institute of Scientific and Technical Information of China (English)

    刘祖强; 薛建阳; 赵鸿铁; 隋

    2013-01-01

    In order to investigate the seismic behaviors of damaged Steel Reinforced Concrete (SRC) frames with special-shaped columns,pseudo-dynamic test was conducted on a model of two-bay and three-story.The mechanical behaviors,such as dynamic response,hysteretic property and stiffness were analyzed.Test results show that when the damaged SRC frame with special-shaped columns experiences earthquake again,the damage starts at the heavily damaged position.The hysteretic loops are full,and the capacity of bearing,energy dissipation and collapse resistance are high.The stiffness is small,so that the story drift is large when the earthquake action is not strong.The damaged SRC frame with special-shaped columns,whose damaged index is not greater than 0.8,does not collapse under the 8 intensity intermediate action.This study can provide reference for the application of SRC frame with special-shaped columns in practical engineering.%为研究损伤型钢混凝土(SRC)异形柱框架的抗震性能,对1榀两跨三层的框架模型进行拟动力试验,分析该结构在水平地震作用下的动力响应、滞回特性、刚度等性能.结果表明:损伤SRC异形柱框架再次遭受地震作用时,首先从损伤严重的部位开始破坏;滞回曲线较为饱满,具有一定的承载能力、耗能能力和抗倒塌能力;刚度较小,当地震作用不大时层间变形较大.损伤指标不大于0.8的SRC异形柱框架,能够承受8度基本烈度的地震作用而不发生倒塌.研究可为SRC异形柱框架的工程应用提供参考.

  15. Damping effect analysis of high-rise steel structure with buckling-restrained column%高层钢结构中BRC跷动技术的减震影响分析

    Institute of Scientific and Technical Information of China (English)

    谭燕秋; 王颖欣

    2013-01-01

    By using finite element analysis software SPA2000, 12 layers of steel frame structure were set up. In X direction and Y direction of original framework bottom column, BRC structure was constructed. The top maximum displacement, base shear and top absolute acceleration time history of three structure scheme under the action of seismic wave as follow EL - Centra wave, Taft wave and TRI_TREASURE ISLAND_90 were analyzed. The results show that comparing with the traditional steel structure, the natural vibration period of BRC structure increased. The control effect of top floor of the maximum displacement and basal shear control is very apparent. This structure has obvious damping effect.%利用有限元分析软件SPA2000,建立12层的钢框架结构,在原框架底层柱X方向、Y方向添加BRC结构.分析三种结构方案在EL-Centro波、Taft波和TRI_TREASURE ISLAND_90这三种地震波作用下的顶层最大位移、基底剪力和顶层绝对加速度时程分析这几种结构反应.结果表明:BRC结构与传统钢结构相比,自振周期有所增加,对顶层最大位移和基底剪力的控制效果非常明显,具有显著的减震效果.

  16. RESEARCH ON DISTORTIONAL BUCKLING BEARING CAPACITY OF COLD-FORMED THIN-WALLED STEEL COLUMNS%冷弯薄壁型钢柱畸变屈曲承载力研究

    Institute of Scientific and Technical Information of China (English)

    姚永红; 武振宇

    2016-01-01

    Cold-formed thin-walled steel has been used widely in building structures due to its many advantages.It has been found that the existing calculated values of distortional buckling bearing capacity of columns can' t reflect the experimental law well, and the calculation process of elastic distortional buckling stress is too cumbersome.The suggested direct strength method considering distortional and global interactive buckling and a rotational restraint calculation formula without iteration used for estimating the elastic distortional buckling stress was presented.The values of distortional buckling bearing capacity calculated by proposed method were safe compared with the experiment data, and decreased with the increasing of the column length, which was in accord with the experimental law.Which provided a reference for revision of Technical Code of Cold-Formed Thin-Walled Steel Structures in the future.%冷弯薄壁型钢构件由于自身的诸多优点,已广泛应用于建筑结构之中.分析发现现有柱试件畸变屈曲承载力计算值不能较好地反映试验规律,并且弹性畸变屈曲应力公式计算过程较繁琐.经过理论分析,提出考虑畸变与整体相关屈曲的直接强度法设计公式,给出无需迭代的转动约束刚度建议公式以用于弹性畸变屈曲应力的计算.通过与试验数据对比发现,所提出的建议公式可以较安全地计算柱试件的畸变屈曲承载力,其计算值随柱长增加而减小,符合试验规律,可为《冷弯薄壁型钢结构技术规范》的修订提供参考.

  17. Steel-column hoisting technology of the large-scale workshop%某大型厂房钢柱吊装施工技术

    Institute of Scientific and Technical Information of China (English)

    杨俊才

    2015-01-01

    以天津某大型电厂主厂房项目为例,论述了在淤泥质粉质粘土软弱地基施工条件下进行大截面钢柱吊装时,施工难度大、造价高的特点,通过对方案优化与技术经济的分析,选用了ZSC43180动臂变幅行走式塔式起重机进行吊装作业,达到了施工进度加快且费用降低的实际效果。%Taking the major workshop project of the large-scale power plant in Tianjin as an example,the paper discusses large-section steel-col-umn hoisting difficulties and high cost under slurry power soft soil foundation,the paper carries out scheme optimization and technological eco-nomic analysis,selects ZSC43180 moving-arm walking-style tower crane for hoisting work. As a result,it achieves the actual effect of speeding up construction schedule and lowing cost as well.

  18. 外露式钢框架柱脚抗震性能试验研究%RESEARCH ON SEISMIC PERFORMANCE OF EXPOSED STEEL-FRAME COLUMNS

    Institute of Scientific and Technical Information of China (English)

    宋岩; 王永

    2012-01-01

    为提高外露式柱脚抗震设计的可靠性,通过缩比试验研究两组不同柱脚试件在循环往复荷载作用下的整体响应和各组成单元的局部响应情况,并根据试验结果,分析柱脚在地震作用下的耗能特性、屈服机制、滞回性能、延性及刚度特性,给出抗震设计建议.%By using scaling test to compare the whole response and the local response of two different base samples under cyclic loading reversals, the thesis analyses the column base's energy consumption behavior, yielding mechanism, the hysteretic behavior, ductility and stiffness characteristics under earthquake. It also gives some suggestions to improve the reliability of seismic design of exposed base.

  19. Research on Hysteretic Model of Frame Structures of Steel Reinforced Concrete Beams and Angle-Steel Concrete Columns%型钢混凝土梁-角钢混凝土柱框架恢复力模型特性研究

    Institute of Scientific and Technical Information of China (English)

    王琨; 袁沈峰; 曹大富; 陈再现; 郑文忠

    2014-01-01

    A hysteretic numerical simulation on the frame structure composed of steel reinforced concrete beams and angle-steel concrete columns was conducted using the beam-column fiber model theory,and compared to the test results.Based on a great number of parameters analysis examples,the characteristics of the hysteretic curves were discussed,and the hysteretic model for single-storey and single-span frame was proposed.This hysteretic model could take the axial compressive ratio and pre-stressing level into account and forecast the hysteretic behavior of the composite frame.Also the results are well agreed with the tests results and numerical simulations,so it could be help for simplifying the elasto-plastic dynamic analysis of the frame structure.%采用梁柱纤维模型对型钢混凝土梁-角钢混凝土柱组合框架滞回全过程开展数值仿真研究,并与试验结果对比.在大量参数分析的基础上,探讨了此类组合框架滞回曲线特点,建立了单层单跨组合框架的荷载-位移恢复力模型,该模型可综合考虑轴压比和预应力度等的影响,能对此类组合框架在水平荷载作用下的滞回性能进行预测,其结果与试验及数值仿真结果一致.相关研究可为简化结构弹塑性动力分析提供参考.

  20. EXPERIMENTAL STUDY OF SEISMIC BEHAVIORS OF LATTICE STEEL REINFORCED CONCRETE FRAME WITH SPECIAL-SHAPED COLUMNS%空腹式型钢混凝土异形柱框架抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    刘祖强; 薛建阳; 赵鸿铁; 高亮

    2014-01-01

    Based on the experimental study on a lattice steel reinforced concrete frame with special -shaped columns under low cyclic reversed loading , the mechanical process and failure patterns were observed .The load-displacement hysteretic loops and skeleton curves and the load and displacement at different stages were obtained .The seismic behaviors such as inter-story drift ratio, ductility, energy dissipation and stiffness degradation were analyzed .Test results show that the failure mechanism of the structure is the beam-hinged mechanism , and it is a typical strong-column and weak-beam structure .The hysteretic loops are plump , and the stiffness degradation is unconspicuous . The ultimate elastic-plastic story drift rotation is larger than the limit value specified by the code , demonstrating the high capacity of collapse resistance .The ductility and energy dissipation of the structure are better than that of the reinforced concrete frame with special-shaped columns .%通过对空腹式型钢混凝土( SRC)异形柱框架进行低周反复加载试验,观察结构的受力过程和破坏形态,获得结构的荷载-位移滞回曲线和骨架曲线以及主要阶段的荷载和位移值,并分析结构的层间位移角、延性、耗能性能及刚度退化等抗震性能指标。试验结果表明:空腹式SRC异形柱框架破坏时形成梁铰机制,属于“强柱弱梁”型结构;滞回曲线较为饱满,刚度退化小;弹塑性极限层间位移角超过规范规定的限值,抗倒塌能力强;延性和耗能能力均优于钢筋混凝土异形柱框架。

  1. Hysteretic Behavior of Steel Reinforced Concrete (SRC) Columns After Fire Exposure%火灾作用后型钢混凝土柱滞回性能研究

    Institute of Scientific and Technical Information of China (English)

    赵框; 毛小勇; 王广勇; 刘维

    2014-01-01

    After exposure to fire,the seismic performance of SRC columns would be deteriorated be-cause of the loss of mechanical properties of concrete under high temperature.To reveal the impact of fire exposure on the seismic performance of SRC columns,the FEM software ABAQUS was used to calculate the hysteretic lateral load versus lateral displacement relations based on full process analysis.Influences of the changing axial compression ratio and fire duration time on the lateral load versus lateral displacement skele-ton curves were discussed.Results showed that the hysteretic curves of the steel reinforced concrete columns are in plump shapes,and have no significant pinch phenomenon after exposure to fire;the ultimate load-car-rying capacity will decrease with the increase of fire duration time and axial compression ratio;fire duration time has a greater impact on the elastic stiffness than axial compression ratio.%型钢混凝土柱在遭受火灾作用后,由于混凝土的力学性能受到损伤,导致柱的抗震性能劣化。为揭示火灾高温损伤对型钢混凝土柱抗震性能的影响,文章运用ABAQUS软件,基于全过程分析方法,建立了火灾作用后型钢混凝土柱滞回性能分析模型,对火灾后SRC柱荷载-位移滞回关系进行计算,分析了轴压比、受火时间对荷载-位移关系骨架线的影响规律。研究结果表明:火灾作用后型钢混凝土柱滞回关系曲线形状饱满,无明显捏缩现象;随着升温时间和轴压比的增大,高温后构件的极限承载力变小;相对于轴压比,升温时间对构件的弹性刚度有着较大的影响。

  2. PULSE COLUMN

    Science.gov (United States)

    Grimmett, E.S.

    1964-01-01

    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  3. 薄壁钢板组合PEC柱(强轴)滞回性能试验研究%Hysteretic behavior of PEC columns (strong axis) with thin steel plate composite section

    Institute of Scientific and Technical Information of China (English)

    方有珍; 陆佳; 马吉; 孙国华

    2012-01-01

    目前我国规范关于PEC组合柱构件及由此组成的结构体系方面的有关内容还基本空白,通过了解国际上在PEC组合柱研究领域的现状,对3个变化混凝土强度等级和拉结筋间距的薄壁钢板组合截面PEC柱足尺试件在恒定轴压下进行水平循环荷载的滞回性能试验。观测记录各个试件加载阶段的薄壁钢板组合截面翼缘的局部屈曲和混凝土裂缝开裂与压溃现象,得到构件的荷载-位移滞回曲线。根据试验结果分析构件的承载力、抗侧刚度、构件的抗震延性和破坏模式等力学性能。结果表明:试验试件具有较好的变形能力和耗散地震能的双重功效;构件的破坏模式为薄壁钢板组合截面翼缘发生局部屈曲,随之柱脚部位混凝土压溃和拉结筋屈服甚至拉断。研究进一步丰富了PEC柱研究成果,为PEC组合柱组成的结构体系规范制订和工程应用提供了合理的理论依据。%According to the development in the field of partially encased composite columns (PEC) and the demand for modification of the relevant structural specification, PEC columns fabricated with thin-wall composite section were investigated. 3 specimens with various concrete strength and transverse link spacing were manufactured to represent the middle-storey column of a PEC column-steel beam composite frame structure. The test of the specimens were conducted under lateral cyclic loading along the strong axis with constant axial compression, and the hysteretic curves were obtained. Base on the test results, the global responses were analyzed, including the load-carrying capacity, lateral- resistant stiffness, energy-dissipation capacity, the ductility property and the failure mode. The specimens exhibited sound ductility and energy-dissipation capacity; the failure mode was primarily local buckling in the flange of a thin-wall composite section, crushing and spalling of concrete at the comer

  4. Experimental Investigation into Axial Compressive Behavior of Cold Formed Thin-Walled Steel Columns with Lipped Channel and Openings%开孔冷弯薄壁卷边槽钢柱轴压性能的试验研究

    Institute of Scientific and Technical Information of China (English)

    姚永红; 武振宇; 成博; 邓君宝

    2011-01-01

    为研究腹板开孔具中间加劲肋的冷弯薄壁卷边槽钢构件的受压性能,对两种截面形式的短柱和中长柱共计16根轴压构件的承载力和屈曲模式进行了试验分析.结果表明:所有试件均发生畸变屈曲失效,中长柱试件还伴随有绕弱轴的整体弯曲;腹板孔洞导致构件屈曲模式发生变化,孔洞周边板件有局部屈曲产生;孔洞的存在使试件承载力降低,短柱试件承载力的减小幅度比中长柱试件的大;同组试件中畸变初始缺陷大的,一般承载力较小,畸变变形偏大;极限承载力下开孔构件的畸变变形一般大于未开孔构件.文中还对所有试件进行了有限元模拟,发现有限元分析结果与试验值吻合较好.%In order to investigate the compression behavior of the cold-formed thin-walled steel columns with lipped channel, intermediate stiffener and openings in the web, 16 axial compressive members, including the short and the medium-length columns in two section forms, were experimentally analyzed in the aspects of bearing capacity and buckling mode. The results show that all of the specimens fail due to the distortional buckling and the medium-length columns have additional overall bending around the weak axis, that the openings in the web result in the changes of buckling modes of the members and the local bucklings of the plates occur around the openings, and that, due to the effects of the openings, the bearing capacities of the specimens decrease and the decrement of the bearing capacity of the short column is greater than that of the medium-length one. Moreover, it is found that, for the specimens in the same test group, the columns with larger initial distortional imperfections are of lower bearing capacities and greater deformations induced by the distortional bucklings, and that the openings generally enhance the deformations corresponding to the ultimate bearing capacity. In addition, all of the tested specimens

  5. Study on shear resistance of aluminum alloy I-section members

    Institute of Scientific and Technical Information of China (English)

    Zhen DONG; Qilin ZHANG

    2008-01-01

    The design method for the shear resistance of aluminum alloy I-section members is presented, taking into consideration of the post-buckling strength of webs and the restraint effect of flanges, and the practical design formulas are proposed. The deflection of aluminum alloy I-section members under concentrated load is simulated by using the finite element method, and several design theories are discussed. The relation of shear resistance to the maximum web displacement reflects that the web of aluminum alloy I-section member is under fewer shears buckling force, while the whole member has higher shear resistance. However, the traditional design method is not able to give the real shear resistance of aluminum alloy I-section members. The proposed design formulas for the shear resistance of aluminum alloy I-section members is used to calculate accurately the post-buckling resistance of webs and the shear resistance contribution of flanges. The results are in a great agreement with the test data of Hamoodi M J, Burr C A, Evans H R and the results from Eurocode9 formulas.

  6. Experimental study on seismic behavior of multi-ribbed composite wall with steel reinforcement concrete frame column%型钢混凝土边框柱复合墙体抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    何明胜; 黄炜; 石磊

    2013-01-01

    Multi-ribbed composite wall with steel reinforcement concrete frame column (SCMRCW) is characterized by high bearing capacity and good seismic behavior, and it is the same with moderate-high storied structure. To show the seismic behavior of SCMRCW,we designed a 1/2 scaleed SCMRCW with 1:1 height-width ratio and two 1/3 scaleed SCMRCW with 2:1 and 3:1 height-width ratio, and carried out low frequency cyclic and reversed lateral load tests. We studied mechanical character, failure mode, bearing capacity, ductility, energy dissipation ability and deformation behavior etc. . The result indicates that the failure process of SCMRCW is similar to MRCW, but the bearing capacity , ductility and energy dissipation ability of SCMRCW is better than that of MRCW. The seismic behavior of the structure is enhanced apparently, when the steel reinforcement concrete frame column is set in MRCW, and the bearing capacity of SCMRCW is reduced with the increasing of height-width ratio, but ductility and energy dissipation ability are increased, and the advantage of shaped steel is obvious.%型钢混凝土边框柱复合墙体具有承载力高、抗震性能好的特点,适用于中高层结构.为研究这种结构形式的抗震性能,本文设计了高宽比为1∶1、模型比例为1/2及高宽比分别为2∶1与3∶1、模型比例为1/3型钢混凝土边框柱密肋复合墙体试件,并进行拟静力试验.根据试验结果,分析了型钢混凝土边框柱密肋复合墙体的受力特点、破坏形态、承载能力、延性、耗能以及变形等抗震性能.分析结果表明:型钢混凝土边框柱的破坏过程与普通密肋复合墙体相似;相同条件下,其承载力、延性及耗能能力都明显好于普通复合墙体;边框柱中加入型钢后,该结构体系的抗震性能得到明显提高;随着高宽比的增加,该结构的承载力减小,但延性、耗能增加,型钢的有利作用更加明显.

  7. Column: lef

    NARCIS (Netherlands)

    Reep, Frans van der

    2012-01-01

    1e alinea column: Ook in je beleggingsbeslissingen is het voor echte performance wellicht tijd om eens voorbij best practices (dan word je namelijk hoogstens tweede) te kijken naar next practices. Als je op zeker speelt, verdien je weinig geld. Want anderen gingen je al voor. Maar kun je nog meer op

  8. PEC柱-型钢梁半刚性框架抗震性能试验研究%Research on Seismic Performance of Semi-rigid Frame of PEC Column-steel Beam

    Institute of Scientific and Technical Information of China (English)

    赵根田; 周慧茹

    2015-01-01

    为了研究PEC柱( partially encased concrete column )-型钢梁半刚性框架的受力特点、滞回性能、延性及破坏模式,对PEC柱-型钢梁顶底角钢连接的半刚性框架进行了低周反复荷载试验。试验共设计了三个框架,参数为轴压比和螺栓边距。通过试验数据得到了此类框架的滞回曲线、刚度退化、延性系数等抗震性能指标,分析了顶底角钢节点的初始转动刚度。试验结果表明:增大轴压比可以提高半刚性框架的极限承载力,承载力提高了8.9%;但延性有所降低,平均位移延性系数减小了37.9%;减小螺栓边距可以提高节点初始刚度,减缓刚度退化,增加框架延性;PEC柱-型钢梁顶底角钢连接的半刚性框架滞回曲线饱满,具有良好的抗震性能。%In order to study the mechanical behavior , hysteretic behavior , ductility and failure mode of semi-rigid frame of PEC column -steel beam , three specimens were designed and tested under low frequency cyclic load-ing.The parameters were the axial compression ratio and angle bolts margins .Based on the experimental study , hysteretic curves , stiffness degradation and ductility factors and other seismic performance results were obtained , the initial rotational stiffness of top-seat angle connections were analyzed .The results show that the increasing of ax-ial compression ratio can improve the ultimate bearing capacity of semi-rigid frame, the bearing capacity increased 8.9%,but also reduce the ductility of the frame ,the average displacement ductility factor decreased 37.9%; re-ducing the angle bolts margins can improve initial rotational stiffness of the joint , reduce the stiffness degradation and increase the ductility of the frame;semi-rigid frame of PEC column-steel beam connected with top-seat angle connections has full hysteretic curves shape and good seismic performance .

  9. 圆CFRP-钢管混凝土压弯构件滞回性能试验研究%Experimental study on hysteretic behaviors of concrete filled circular CFRP-steel tubular beam-columns

    Institute of Scientific and Technical Information of China (English)

    车媛; 王庆利; 邵永波; 侯婷婷

    2011-01-01

    A total of 12 specimens were experimentally investigated to study the hysteretic behaviors of concrete filled circular CFRP-steel tubular beam-columns.The test results indicated that,CFRP can effectively provide circumferential confinement and longitudinal strengthening for the concrete filled circular steel tube,and the local bulking of the steel tube are delayed or prevented.Mid-span load-deflection hysteretic curves and moment-curvature hysteretic curves of all the specimens display perfect hysteretic behaviors.During the later loading period,there are not load bearing capacity drop for members without axial load,while there are obvious load carrying capacity drop for members with axial load.Analysis of the test results indicated that,the steel tube and its outer CFRP material can cooperate both longitudinally and circumferentially,the longitudinal strain and the circumferential strain of one same point have opposite sign,also,the deflection curves of all the members are approximately half sin wave.Calculation results showed that,the strength degradation is not obvious,axial compression ratio and strengthening factor of the longitudinal CFRP can enhance the bending strength and stiffness of the members and can delay stiffness degradation of the members,but they will decrease ductility and accumulated energy dissipation of the members,also,axial compression ratio is beneficial to seismic behaviors within certain range.%进行了12个圆CFRP-钢管混凝土压弯构件的滞回性能试验研究。试验结果表明,CFRP对圆钢管混凝土有很好的环向约束和纵向增强作用,钢管的局部屈曲得到了延缓或消除。所有试件的跨中荷载-挠度曲线和弯矩-曲率曲线均较为饱满,表现出很好的滞回性能。在加载后期,无轴压力试件的承载力无下降,而有轴压力试件的承载力明显下降。对试验结果的分析表明,钢管和CFRP在纵向和环向都可以协同工作;同一点的纵向应变和环向应

  10. Numerical Analysis of Elastic Distortional Buckling for Cold-formed Thin-walled Steel Lipped Channel Columns%冷弯薄壁卷边槽钢柱弹性畸变屈曲数值分析

    Institute of Scientific and Technical Information of China (English)

    姚永红; 武振宇

    2012-01-01

    The distortional buckling which becomes a significant failure mode probably appears prior to the plates local buckling when high-strength steel with thinner cross-sections are widely used in building. The failure mechanism of distortional buckling is different from the local buckling, and the computing process of those elasticbuckling stress are quite distinct. The present procedures for the calculation of critical elastic distortional buckling stress are very complicated and cumbersome, and the estimation of the buckling stress in design is depended on the numerical analysis method which the finite strip method and finite element method are usually used. A comparison of the results of elastic distortional buckling stress and half wavelength got by finite strip method and finite element method were conducted, it was found that the values were very close to each other. Two methods can be used for predicting the elastic distortional buckling of cold-formed thin-walled steel columns.%随着高强冷弯薄壁型钢在建筑业中的大规模应用,使得构件畸变屈曲的出现可能先于板件的局部屈曲,成为构件失效控制模式.畸变屈曲的破坏机理不同于局部屈曲,其弹性屈曲应力计算过程也大相径庭.现有畸变屈曲临界应力的计算公式异常复杂,在设计中可以借助数值分析的方法进行计算.有限条方法和有限元方法是常用的两种数值分析方法,采用有限条方法和有限元方法计算了冷弯薄壁型钢柱构件弹性畸变屈曲应力和屈曲半波长度,对比研究发现二者结果非常接近,均可用于分析柱试件的弹性畸变屈曲.

  11. Local Compression of Concrete Columns Under Foot Flange of Steel Tube Tower%钢管塔法兰底板下的混凝土立柱局部受压

    Institute of Scientific and Technical Information of China (English)

    左元龙; 贤鹏; 董建尧

    2013-01-01

    According to《Technical Regulation of design for tower and pole structure of overhead transmission line》(DL/T5154-2002),the strength analysis of the square tower foot plate under compression should be calculated with the uniform reaction force(Putting aside the correctness of this view), in no longer checking the concrete local compression under the tower bottom plate;steel tube tower foot flange plate is an annular area of the base plate and the thickness of the plate is often less than the square tower foot plate, which concrete local compression of the calculation were not listed in the present Code and Technical regulations;for"1000kV Huainan-Shanghai (Anhui Power East) transmission line ", the project was made up of double-loop steel tube tower, the foot flange bolts using a small diameter of specifications and more number, with the calculation method proposed in this paper, which can meet the local compression of the concrete column under the tower feet.%现行《架空送电线路杆塔结构设计技术规定》(DL/T5154-2002),对方型塔脚底板受压时按照均布反力验算底板的强度(暂且不论此观点的正确性),在均布反力的作用下,不再验算塔脚板下混凝土立柱的局部受压;而钢管塔的地脚法兰板为圆环状,底板的面积和板的厚度往往小于方型塔脚底板,其混凝土局部受压的计算在现行的规范和规定中均未列出;“1000kV淮南-上海(皖电东送)输电线路工程”全线为双回路钢管塔,在地脚法兰的螺栓采用小规格多数量,用本文提出的计算方法,可满足塔脚法兰底板下混凝土立柱的局部受压。

  12. 冷成型轴压方钢管柱破坏模式的数值模拟研究%NUMERICAL SIMULATION OF THE FAILURE MODES FOR COLD-FORMED SQUARE HOLLOW SECTION STEEL COMPRESSION COLUMNS

    Institute of Scientific and Technical Information of China (English)

    马成; 叶继红

    2009-01-01

    Ultimate bearing capacity and failure modes of cold-formed square hollow section steel compression columns are studied by numerical simulation,and comparisons of experimental results are made to reveal the whole process correctly. Material nonlinearity is considered in the analysis, as well as geometric nonlinearity. The issues that needed to be mentioned in cold-formed compression members modeling by ANSYS are elaborated, and the influences of parameters such as grid density and initial imperfection on simulation are investigated according to the results of numerical simulation. The reasonable finite element model, meshing and the applying method of initial imperfection are proposed. The results of numerical simulation are in good agree with the experimental results. The suggestions of simulating the boundary conditions of the columns in practical engineering are also given.%为准确揭示冷成型轴压方钢管柱的受力全过程,对其极限承载力和破坏模式进行了数值模拟研究,并与试验结果进行了对比.分析中考虑了材料非线性和几何非线性的影响.详细阐述了使用ANSYS进行冷成型轴压方管柱建模时需要注意的问题,并根据模拟结果分析了网格密度、初始缺陷等参数对模拟效果的影响.提出了合理的有限元分析模型、网格划分密度,初始缺陷施加方式等一系列具体措施.数值模拟结果与试验结果吻合良好.给出了实际工程中拄边界条件模拟方法的建议.

  13. Slurry bubble column hydrodynamics

    Science.gov (United States)

    Rados, Novica

    Slurry bubble column reactors are presently used for a wide range of reactions in both chemical and biochemical industry. The successful design and scale up of slurry bubble column reactors require a complete understanding of multiphase fluid dynamics, i.e. phase mixing, heat and mass transport characteristics. The primary objective of this thesis is to improve presently limited understanding of the gas-liquid-solid slurry bubble column hydrodynamics. The effect of superficial gas velocity (8 to 45 cm/s), pressure (0.1 to 1.0 MPa) and solids loading (20 and 35 wt.%) on the time-averaged solids velocity and turbulent parameter profiles has been studied using Computer Automated Radioactive Particle Tracking (CARPT). To accomplish this, CARPT technique has been significantly improved for the measurements in highly attenuating systems, such as high pressure, high solids loading stainless steel slurry bubble column. At a similar set of operational conditions time-averaged gas and solids holdup profiles have been evaluated using the developed Computed Tomography (CT)/Overall gas holdup procedure. This procedure is based on the combination of the CT scans and the overall gas holdup measurements. The procedure assumes constant solids loading in the radial direction and axially invariant cross-sectionally averaged gas holdup. The obtained experimental holdup, velocity and turbulent parameters data are correlated and compared with the existing low superficial gas velocities and atmospheric pressure CARPT/CT gas-liquid and gas-liquid-solid slurry data. The obtained solids axial velocity radial profiles are compared with the predictions of the one dimensional (1-D) liquid/slurry recirculation phenomenological model. The obtained solids loading axial profiles are compared with the predictions of the Sedimentation and Dispersion Model (SDM). The overall gas holdup values, gas holdup radial profiles, solids loading axial profiles, solids axial velocity radial profiles and solids

  14. Experimental Testing Of Partially Encased Composite Beam Columns

    Directory of Open Access Journals (Sweden)

    Ehab M. Hanna

    2016-01-01

    Full Text Available The past few decades have seen outstanding advances in the use of composite materials in structural applications. There can be little doubt that, within engineering circles, composites have revolutionized traditional design concepts and made possible an unparalleled range of new and exciting possibilities as viable materials for construction. In addition to the well-known advantages of composite columns, partially encased composite columns offered simplified beam-to-column connection as well as reduced or omitted shuttering thus achieved more cost effective construction. Some companies have patented these new types of partially encased composite column made of light welded steel shapes; moreover, the Canadian Institute of Steel construction CISC has recognized and codified this type of columns. In This paper, Partially Encased Composite Beam Columns is introduced; experimental studies are made on five partially encased beam columns to investigate the behavior of eccentrically loaded partially encased composite columns using different parameters.

  15. 薄壁方钢管-砂卵石组合短柱轴压力学性能研究%Study of the Mechanical Properties of Thin-Walled Square Steel Tube Sandy Pebble Composite Short Columns to Axial Loads

    Institute of Scientific and Technical Information of China (English)

    邓勇军; 姚勇; 刘欢; 陈代果; 徐刚

    2014-01-01

    保持砂卵石压实系数在大于87.7%的范围,对两组6根薄壁方钢管-砂卵石短柱的轴压静力性能进行了试验研究,分析了试件的破坏形态、极限承载力、轴向荷载-位移曲线以及轴向荷载-应变曲线等数据。试验结果表明:(1)薄壁方钢管-砂卵石短柱的破坏模式均为局部失稳破坏,且破坏后砂卵石随钢管变形而变形;(2)薄壁方钢管-砂卵石短柱轴向荷载-位移曲线根据钢管与砂卵石分担荷载情况大致可以分为钢管主要受力阶段、砂卵石压实阶段、砂卵石主要受力阶段、破坏阶段4个阶段;(3)增加壁厚能增强薄壁钢管与砂卵石的相互作用。%Under keeping the compaction factor of sandy pebble is greater than the suggestion of the range of 87 .7%, take static experimental study on the axis pressure mechanical property of two groups of six sandy -pebble-filled thin-walled square steel tubular short columns .The failure characteristics , the ultimate bearing capacity , the load-strain curves and the load -compression displacement curves of dif-ferent test specimens were comparatively analyzed .The experimental results indicate that ( 1 ) thin -walled square steel tube -sandy pebble short column failure mode are local buckling failure , the de-struction of the sand and gravel with deformed steel deformation ;(2) Thin-walled square steel tube -sandy pebble short column axial load -displacement curve according to the steel tube and sandy pebble all share the load situation can be divided into four stages: main stress on steel stage , compaction on sandy pebble stage , main stress on sandy pebble stage , failure stage;( 3 ) Increasing the wall thickness can significantly enhance the interaction of thin -walled steel pipe with sandy pebble .

  16. 型钢边缘构件-钢连梁焊接型混合连肢墙节点滞回性能有限元分析%FEM Analyses on Hysteretic Behavior of Steel Coupling Beam-column Connections with Steel Boundary Elements Welded in Hybrid Coupled Shear Wall Systems

    Institute of Scientific and Technical Information of China (English)

    徐明; 苏明周; 王丽; 李旭东

    2012-01-01

    The finite element analyses on hysteretic behavior of steel coupling beam-column connections with steel boundary elements welded in hybrid coupled shear wall system were performed by using the FEM software ABAQUS for numerical simulation,so as to obtain the seismic performance of hybrid coupled shear wall system under low cyclic loading.The results of the finite element analyses agree quite well with experimental results.Meanwhile,the finite element analysis results and experimental results all indicate that the hysteretic curve of connections in hybrid coupled wall is full,and the ductility factor and ultimate bearing capacity are high,which shows that this kind of connection has high seismic performance,and is suitable for using in the high-rise buildings in high-intensity earthquake areas.%通过利用ABAQUS有限元软件对型钢边缘构件-钢连梁焊接型混合连肢墙(HCW)节点滞回性能进行有限元分析,研究混合连肢墙在低周循环荷载作用下的抗震性能,并将有限元计算结果与试验结果进行了对比,吻合情况较好。同时,试验研究与有限元分析结果均表明:节点滞回曲线饱满,且延性系数及极限承载力较高,表明节点具有良好的抗震性能。

  17. Experimental study on seismic behaviors of solid steel reinforced concrete edge frame with special-shaped columns%实腹式型钢混凝土异形柱边框架抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    薛建阳; 刘祖强; 赵鸿铁; 周鹏

    2012-01-01

    In order to investigate the seismic behaviors of solid steel reinforced concrete edge frames with special-shaped columns, a model of two-bay and three-story frame was tested under low cyclic reversed loading. The failure process and patterns were observed. The mechanical behaviors such as load-displacement hysteretic loops and skeleton curves, load carrying capacity, inter-story drift ratio, ductility, energy dissipation and stiffness degradation of the frame were analyzed. Test results show that the failure mechanism of the solid SRC edge frame with special-shaped columns is the beam-hinged mechanism, satisfying the seismic design principle of "strong column and weak beam". The hysteretic loops are plump, and the stiffness degradation of the structure is insignificant. As the frame fails, the equivalent viscous damping coefficient and the ductility factors may exceed 0.24 and 5.3, respectively. The ultimate elastic-plastic story drift rotation is larger than the limit value specified by the seismic code, indicating the high capacity of collapse resistance. The solid SRC edge frame shows excellent seismic behaviors, and can be adopted in high-rise buildings and constructed in high seismic fortification zone.%为研究实腹式型钢混凝土(SRC)异形柱边框架的抗震性能,对1榀两跨三层的框架模型进行低周反复荷加载试验。观察结构的受力过程及破坏形态,并分析结构的荷载一位移滞回曲线和骨架曲线、承载能力、层间位移角、延性、耗能及刚度退化等力学特性。结果表明:实腹式SRC异形柱边框架破坏时形成梁铰机制,符合“强柱弱梁”的要求;滞回曲线饱满,刚度退化小;破坏时,等效黏滞阻尼系数和位移延性系数分别大于0.24和5.3;弹塑性极限层问位移角大于抗震规范规定的限值,抗倒塌能力强。实腹式SRC异形柱边框架显示出良好的抗震性能,可以应用于高抗震设防烈度区的建筑以及高层建筑中。

  18. Parametric analysis of ultimate bearing capacity of Q460 high strength steel welded box columns under axial compression%Q460高强钢焊接箱形柱轴心受压极限承载力参数分析

    Institute of Scientific and Technical Information of China (English)

    李国强; 王彦博; 陈素文; 孙飞飞

    2011-01-01

    A parametric analysis on ultimate bearing capacity of fabricated box-section steel columns with the nominal yield strength of 460 MPa was presented.The analysis aims to investigate whether the current design codes for ordinary steel are applicable for high strength steel columns or whether the codes need to be modified to include high strength steel.The calculation program base on numerical integration method(NIM) was written by authors.And the commercial finite element analysis software ANSYS was also adopted for comparison.Numerical models including initial geometric imperfections and residual stresses were verified by test results.The main parameters were width to thickness ratio and column slenderness,which ranged from 7.8 to 17.2 and from 10 to 130 respectively.The effects of residual stresses and initial geometric imperfections on the ultimate bearing capacity with varyious parameters were investigated and discussed.A proposal for the design of high strength steel columns was given based on the comparison of parametric analysis with GB 50017—2003.The curve b,which is higher than the suggested curve c for ordinary steel welded box columns,suits better for the design of box columns fabricated from Q460 steel plates with width to thickness ratio no more than 20.%为研究现有钢结构设计规范是否仍适用于高强钢中厚板焊接箱形柱的设计,对Q460钢轴心受压柱的极限承载力进行了参数分析。采用数值积分法,并与有限元程序ANSYS的数值计算结果作进行对比。数值模型考虑了1/1 000柱长的初始弯曲及由相应截面尺寸残余应力试验提出的残余应力分布简化模型。试件的主要参数为截面宽厚比(7.8~17.2)与柱长细比(10~130)。计算结果表明:考虑相同初始缺陷的有限单元法与数值积分法所得计算结果吻合较好;与普通强度钢柱相比,初始几何缺陷对高强钢焊接箱形柱的极限承载力影响降低,柱的稳定系数

  19. Experimental study on bearing capacity of welded H-section columns using Q460 high strength steel under bending and axial compression%Q460高强度钢材焊接H形截面弱轴压弯柱承载力试验研究

    Institute of Scientific and Technical Information of China (English)

    李国强; 闫晓雷; 陈素文

    2012-01-01

    This paper presented a study on the ultimate bearing capacity of high strength steel columns under eccentric load.Through the tension coupon tests and the measurement of the residual stress of H-section,initial geometric imperfections and ultimate loads of each column,tests on six specimens of welded H-section columns with three different cross sections made by Q460 high strength steel were conducted.The measured ultimate loads were compared with the values predicted by design formulas specified in Chinese codes.FEA models were employed to simulate the results of the tests.Initial deficiencies including geometric imperfection and residual stress were considered in the FEA models.The distribution of the residual stress and the material properties used in FEA models were taken from the tests.Q460 low alloy steel has high strength and high performance plastic property.The distribution of the residual stress of welded H-section columns using Q460 high strength steel and the distribution of the residual stress using ordinary steels were basically identical.The experimental results show that the bearing capacity of welded H-section columns of high strength steel are higher than the values predicted according to the Chinese code for design of steel structures.The results predicted by FEA models fit well with those obtained from the tests.This study provides the basis for the application of Q460 high strength steel in practical engineering.%为了研究高强度钢材中厚板焊接H形截面压弯柱的承载力,采用国产Q460高强度钢材11 mm、21 mm中厚板制作了6个焊接H形截面压弯柱,试件截面自由外伸翼缘板宽厚比分别为7、5、3,长细比分别为40、55、80。通过对Q460低合金高强度钢材的材性测试、3种焊接截面残余应力测试、各试件初始几何缺陷测量及承载力试验,进行了H形截面弱轴压弯构件整体失稳承载力的试验研究,并与采用GB 50017—2003《钢结构设计规范》进行计

  20. 钢管混凝土边框内藏带斜肋钢板中高剪力墙抗震性能试验%Experiments on the seismic behavior of mid-rise shear walls with CFST boundary columns and concealed steel plates with diametrically opposed cross-braces

    Institute of Scientific and Technical Information of China (English)

    董宏英; 张文江; 曹万林; 于传鹏

    2013-01-01

    提出了钢管混凝土边框内藏斜撑肋钢板组合中高剪力墙.为研究这种组合剪力墙的抗震性能,进行了5个不同构造的中高剪力墙模型低周反复荷载试验.分析了试件的损伤特征、承载力、耗能、滞回特性,提出了正截面抗弯承载力计算模型,计算结果与试验符合较好.研究表明:钢管混凝土边框内藏钢板组合剪力墙具有较高的承载力和良好的耗能性能;钢管混凝土边框内藏带斜撑肋钢板中高剪力墙,适于在墙体厚度小于钢管尺寸或内藏钢板厚度较薄的“强边框、弱墙体”情况下应用,可明显减轻钢管混凝土边框底部的损伤,延缓墙体性能退化,提高组合剪力墙的抗震能力.%A new design of mid-rise shear wall with CFST columns and concealed steel plate with diametrically opposed cross-braces is hereby set forward.In order to quantify its seismic behavior,5 mid-rise shear wall specimens are tested under low frequency cyclic loading.The ensuing failure characteristics,load-bearing and energy dissipation capacities,hysteretic behavior of these specimens are discussed herein.The calculated model of bend resistant load-bearing capacity is established and the results agree well with the experimental ones.The experiments show that the composite shear walls with CFST columns and embedded steel plate have a higher load-bearing and better energy dissipation capacities compared to conventional mid-rise shear walls.The proposed mid-rise shear wall with CFST boundary columns and concealed steel plate with diametrically opposed cross-braces is suitable for shear walls where thickness is smaller than the cross section of the CFST columns or shear walls with low-thickness embedded steel plates.The inclined cross-braces reduce the damage typically seen at the bottom of CFST columns,delay the stiffness degradation,and improve the integrative seismic behavior of the entire wall.

  1. 钢板箍螺栓连接高强复合螺旋箍装配整体式柱抗震性能试验%SEISMIC BEHAVIOR RESEARCH OF STEEL PLATE HOOP-BOLT PREFABRICATED COLUMN CONFINED BY HIGH-STRENGTH COMPOSITE SPIRAL STIRRUPS

    Institute of Scientific and Technical Information of China (English)

    李进; 陈鹏; 魏威; 李青宁

    2014-01-01

    通过低周反复拟静力试验方法,研究钢板箍螺栓连接装配整体式柱的抗震性能。试验共设计4根长柱试件,观察各试件开裂、屈服、破坏全过程和破坏状态,得出各试件荷载-位移滞回曲线和骨架线,对比研究各试件承载力、延性和耗能能力,研究钢板箍螺栓连接方式的可行性。试验证明:钢板箍螺栓连接高强复合螺旋箍筋装配整体式柱和现浇整体柱具有相当的承载力和抗震能力,在连接可靠的情况下可以在工程中代替现浇柱。%In order to study the seismic behavior of steel plate hoop-bolt prefabricated column by high-strength composite spiral stirrups , the low cyclic loading tests were carried out .Four long column specimens were designed . Cracking, yield, destroyed process and destroyed state of specimens were observed in the tests , and the load-displacement hysteretic curves and skeleton curves of each specimen were also obtained .Comparative study on carrying capacity , ductility and energy dissipation capacity of each specimen was conducted , and analysis of the reliability of steel plate hoop-bolt connection was done .The test proves that steel plate hoop-bolt prefabricated column confined by high-strength composite spiral stirrups has about the same bearing capacity and seismic capacity as compared with cast-in-place column, and the prefabricated column can be used to replace the cast-in-place column in project in case of secure connections .

  2. 冷弯薄壁型钢C型构件压弯屈曲机理与滞回模型研究%Research on hysteretic model and buckling mechanism of cold-formed C-section steel column

    Institute of Scientific and Technical Information of China (English)

    杨娜; 彭雄

    2015-01-01

    对冷弯薄壁型钢C型构件进行竖向常轴力作用与水平循环荷载同时作用下的加载试验,以探索冷弯薄壁型钢C型构件滞回性能特点以及轴压比、截面宽厚比等参数对试件破坏行为的影响。基于截面应力分布规律和薄板屈曲理论,提出格构机理模型,试验和数值模拟结果验证了该模型的合理性;采用数值模拟方法,分析薄壁构件压弯屈曲机理,获得薄壁C型构件滞回曲线特征,总结影响其滞回性能的关键影响参数。研究表明:大轴压比对试件滞回性能有极大的削弱作用;过早出现的局部屈曲是薄壁C型构件破坏的关键原因;提出的滞回模型能够体现局部屈曲对构件滞回性能的影响。%Several specimens are loaded with axial force and horizontal cyclic force,in order to obtain the hysteretic performance and the influence of axial compression ratio and aspect ratio on the buckling performance. By applying the mechanism model and comparing data of FEM and the test,the buckling mechanism of thin-walled specimens are researched and the hysteresis curves and key factors are obtained as well. The research reveals that big axial compression ratio brings a serious decrease on hysteretic performance and local buckling plays a great negative role during the loading process. Lastly,based on the conclusion of hysteretic characteristics of cold-formed C-section steel columns,the mechanism model is used for the theoretical derivation and numerical fitting on the hysteresis model including the skeleton curve and stiffness degradation law. This hysteresis model reflects the influence of local buckling on hysteretic behavior,which at the same reveals the hysteresis characteristics of thin-walled specimens under hysteretic load.

  3. Effects of distortional imperfections on mechanical properties of cold-formed thin-walled steel columns%畸变缺陷对冷弯薄壁型钢柱力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    姚永红; 武振宇

    2012-01-01

    In order to investigate the effects of distortional imperfections on mechanical properties of cold-formed thin wall steel lipped channel columns with an intermediate V-stiffener in the web, the initial distortional imper-fections of 20 specimens were measured. After the measurement device and method were introduced, the distribu-tion maps of distortional imperfections along the length of specimens were painted, and the maximum value and the mean of distortional imperfections of the specimens were given. The effect of distortional imperfection on the load-carrying capacity and lateral deformation of distortional buckling were studied by finite element method. The relative lower load-carrying capacity and more significant lateral distortional buckling deformation were obtained by inputting the larger initial distortional imperfection. The maximum and mean distortional imperfections were con-sidered in numerical simulation. It is found that the data of load-carrying capacity and the maximum lateral distor-tional buckling deformation of specimens show good agreement with the experimental results by importing the mean distortional imperfection. A method to consider the distortional imperfection for numerical simulation is presented.%为研究畸变缺陷对腹板V形加劲冷弯薄壁卷边槽钢柱力学性能的影响,测量了20个试件的畸变初始缺陷.介绍了缺陷的测量装置及方法,绘制了畸变缺陷沿试件纵向分布图,给出了所测构件畸变缺陷最大值和平均值.用有限元方法分析畸变缺陷对畸变屈曲承载力和畸变屈曲侧向变形的影响,结果表明,输入的初始缺陷值越大,对应的试件极限承载力越小,畸变屈曲侧向变形越大.数值模拟时分别考虑畸变缺陷最大值以及平均值,与试验结果对比发现,输入试件纵向畸变缺陷平均值所得的承载力以及变形值与试验数据吻合较好.给出了数值计算时畸变缺陷的建议取值方法.

  4. 多室式钢管混凝土T形短柱轴压性能试验研究%Experimental study of the properties of axially loaded multi-cell T-shaped concrete-filled steel tubular stub columns

    Institute of Scientific and Technical Information of China (English)

    刘林林; 屠永清; 叶英华

    2011-01-01

    对钢管混凝土T形柱进行合理的改进,提出多室式钢管混凝土T形柱(MT-CFST柱)。进行12个短柱试件的轴压试验并对其破坏过程作了详细描述,给出试件的轴压应力.纵向平均应变曲线,同时也考察试件的破坏形态及截面各尺寸、板件布置方式、钢板厚度、混凝土强度等因素对试件力学性能的影响。试验结果表明:多室式钢管混凝土T形柱能较好地增强T形截面内钢材对混凝土的约束作用,发挥两种材料的组合性能;试件的破坏以局部鼓曲和整体剪切两种形式为主,轴压性能受腹板高度、钢板厚度及混凝土强度的影响较大。同时,参考国内外4种钢管混凝土规范中的计算方法对试件的承载力进行计算,经过对比后发现,按ECA规范计算的结果与试验结果符合最好。%Multi-cell T-shaped concrete-filled steel tubular (MT-CFST) column is an improvement of T-shaped concretefilled steel tubular (T-CFST) column. Twelve MT-CFST stub columns under axial compression were tested and the failure processes were described in detail. The axial stress-longitudinal average strain curves were provided, and the effects of the factors including cross section dimension, steel plate layout, thickness of the steel plate and concrete strength on the mechanical behaviors of the specimens were discussed. It is shown that MT-CFST stub columns may enhance the interaction between the two component materials and take advantage of their performances. The primary failure modes of the specimens involved local bulge failure and shear failure. Properties of the MT-CFST columns are mainly influenced by the web length, steel plate thickness and the concrete strength. The axial load capacities of the specimens were calculated according to four design codes for CFST columns. The comparison between the calculations and experimental data indicates that the EC4 method provides much better estimate of

  5. 腔内带钢筋笼多腔钢管混凝土巨型柱轴压性能试验研究%Experimental Study on Axial Compression Performance of Multi-Cell CFST Mega-Columns with Steel Reinforcement Cage Inside

    Institute of Scientific and Technical Information of China (English)

    曹万林; 王智慧; 彭斌; 董宏英; 武海鹏; 殷超; 陈利民

    2012-01-01

    以某超高层巨型框架结构巨型柱为原型,进行了3个多腔钢管混凝土巨型柱模型试件的轴压性能试验研究,模型按1/12缩尺.3个试件的几何尺寸和腔体钢板均一致,各试件主要参数:试件1腔内加设钢筋笼,混凝土强度等级为C30;试件2腔内不加设钢筋笼,混凝土强度等级为C40;试件3腔内加设钢筋笼,混凝土强度等级为C40.试验分析了各试件的承载力、刚度及退化过程、残余变形、破坏特征等.研究表明:腔内设置钢筋笼的多腔钢管混凝土巨型柱具有良好的延性和抗压工作性能,可用于工程设计.%According to a mega-column from a super high-rise mega-frame structure, three 1/12 scaled multi-cell CFST mega-column models were tested under axial compression. All the geometric dimensions and the steel plates of the three specimens were same with eachother. Specimen 1 was made from concrete C30 with steel reinforcement cage inside; specimen 2 was made from concrete C40 without steel reinforcement cage; specimen 3 was made from concrete C40 with steel reinforcement cage inside. The load-bearing capacity, stiffness and its degeneration, residual deformation and failure characteristic of models have been compared and analyzed. The study shows that the multi-cell CFST mega-column with steel reinforcement cage inside has good ductility and good compression work performance. And it can be used in the design practical of engineering.

  6. The Dissipative Column: A New Hysteretic Damper

    Directory of Open Access Journals (Sweden)

    Bruno Palazzo

    2015-02-01

    Full Text Available A new replaceable hysteretic damper to better control seismic building damage, consisting of two or more adjacent steel vertical elements connected to each other with continuous mild/low strength steel shear links, is proposed and investigated in this paper. New Dampers, called Dissipative Columns (DC, continuously linked with X-shaped steel plates, provide additional stiffness and damping to a lateral system by using a basic and minimally invasive construction element: the column. Working in a way similar to coupled shear walls, the proposed element behavior is theoretically analyzed at linear and non-linear ranges. In fact, considering different restrained cases, a parametric analysis is developed in order both to evaluate the effect of the main geometrical and structural parameters and to provide the design capacity curves of this new damper. The DC can be considered a new damping device, easy to install in new as well as existing buildings in order to protect them from seismic damage.

  7. 冷弯薄壁型钢拼合箱形截面立柱轴压性能试验研究%Experimental Analysis on Behavior of Cold-formed Steel Box Built-up Section Columns under Axial Compression

    Institute of Scientific and Technical Information of China (English)

    聂少锋; 周天华; 袁涛涛; 高婷婷; 吴函恒

    2012-01-01

    17 specimens of cold-formed steel box built-up setion columns were tested under axial compression load. The section forms were divided into two categories: A and B. Load-displacement curves and failure characteristics of specimens were obtained. The test results are compared with the caculated results according to "effective ratio of width to thickness" in code of "Technical code of cold-formed thin-wall steel structures" (GB 50018 - 2002), "effective section method" and "direct strength method" in AISI specification. The results show that: the failure characteristics of LC and MC series columns are overall flexural buckling, while SC series columns are local buckling and ends confined damage. The ultimate bearing capacity of B categories section columns is three times as great as that of A categories section columns, so it has the effect of "1 + 1>2". The results calculated according to "GB50018" and AISI specification are much conservative for LC series columns of A categories section, while in agreement with test results for MC and SC series columns. For B categories section columns, the calculated results are non-conservative for LC and MC series columns, while conservative for SC series columns.%对17根冷弯薄壁型钢拼合箱形截面立柱的轴压性能进行试验研究,截面分为A、B两类,得到了各试件荷载-位移曲线和破坏特征,并将试验结果与《冷弯薄壁型钢结构技术规范》(GB 50018-2002)“有效宽厚比法”和美国相关规范中“直接强度法”、“有效截面法”计算结果进行对比分析.结果表明:LC和MC系列立柱的破坏模式为整体弯曲屈曲,SC系列立柱则为局部屈曲和端部承压破坏;B类试件的最大承载力大于A类截面试件的最大承载力的2倍,即有“1+1>2”的拼合效应;对于A类截面LC系列立柱,GB 50018和AISI规范公式计算结果过于保守,而对于MC和SC系列试件,公式计算结果与试验结果比较吻合;对于B类截面LC和MC

  8. EXPERIMENTAL RESEARCH ON STEEL-REINFORCED CONCRETE FILLED GFRP TUBE COLUMNS SUBJECTED TO AXIAL LOADING%玻璃纤维增强材料管劲性钢筋混凝土组合柱轴心受压试验研究

    Institute of Scientific and Technical Information of China (English)

    陈百玲; 王连广; 秦国鹏

    2011-01-01

    According to the experimental research on 8 composite columns,the axial compression property of GFRP tube filled with steel reinforced concrete was studied. The test results show that GFRP tube, concrete and section steel carry loads alone at the beginning of loading. Then the fiber surface of GFRP tube grows stretch marks when the loads reach 60% ultimate loads and GFRP tube has an obvious hooped effect on concrete when the loads reach 70% ultimate loads. While the loads reach 80% ultimate loads, GFRP tube can generate frequent noise. The damage of test specimen begins with the fracture of GFRP tube, the yield of steel and the crushing of concrete. The nonlinear analysis program of composite columns was developed, and the calculated results agree well with the experimented resuhs. According to the computing and analyses, the bearing capacity of composite columns is enhanced with the increase of GFRP tube wall thickness, concrete strength grade and steel ratio.%对8根组合柱进行试验,研究玻璃纤维增强材料(GFRP)管劲性钢筋混凝土组合柱的轴心受压性能。研究结果表明:荷载作用初期,GFRP管、混凝土及型钢单独受力,当荷载达到极限荷载60%左右时,GFRP管的纤维表面出现白纹,当荷载达到极限荷载的70%左右时,GFRP管对混凝土的套箍作用明显增加,当荷载达到极限荷载80%左右时,GFRP管出现频繁的响声,试件的破坏开始于GFRP管破裂、钢材屈服、混凝土压碎。编制组合柱的非线性分析程序,模拟计算结果与试验结果吻合良好。组合柱的承载力随着GFRP管壁厚度的增加、混凝土强度等级的提高及含钢率的增加而提高。

  9. Mechanical behaviors of the joint between steel reinforced concrete L-shaped column and concrete beam frame under low-cyclic reversed loading%型钢混凝土L形柱—混凝土梁节点的受力性能

    Institute of Scientific and Technical Information of China (English)

    陈宗平; 王妮; 薛建阳; 胡秀杰

    2011-01-01

    为了研究型钢混凝土(SRC)L形柱—混凝土梁框架节点的受力性能,设计了4个试件进行低周反复加载试验,揭示了其受力破坏机理;获取了节点受力全过程的荷载—位移滞回曲线和荷载—应变滞回曲线,分析了其变形能力和能量耗散能力.结果表明:反复荷载作用下SRC异形柱框架角节点的抗震性能良好,荷载—位移滞回曲线的滞回环饱满、对称,其抗震承载能力高,综合抗震指标明显优于钢筋混凝土异形柱框架角节点的.研究可为SRC异形柱框架角节点受力机理的分析和承载力计算方法的建立提供试验依据.%In order to reveal the mechanical behavior of joints between steel reinforced concrete (SRC) L-shaped column and concrete beam frame, 4 specimens were designed for low-cyclic reversed loading test. Failure mechanism of the joints is revealed. The hysteretic curves of load-displacement relation and load-strain relation of the joints were obtained, and deformability and dissipation capacity of the joints were analyzed. The results indicate that the seismic behavior of the corner joints in steel reinforced concrete special-shaped column frame is good. The load-displacement hysteretic curves of the specimens are symmetric and plump, and the seismic index of the joints are higher than those of the joints in RC special-shaped column frame. This study can be helpful for the analysis of mechanism and the establishment of calculation method of the corner joints in steel reinforced concrete special-shaped column frame.

  10. Study on mechanical behaviors of steel reinforced concrete T-shaped column-beam joints%反复荷载作用下型钢混凝土异形柱框架边节点力学性能试验研究

    Institute of Scientific and Technical Information of China (English)

    薛建阳; 王玮; 刘义; 刘祖强; 赵鸿铁

    2011-01-01

    According to the experimental study on 9 specimens of steel reinforced concrete (SRC) T-shaped column-beam joints under low cyclic reversed loading, the influence of the steel layout and the axial compression ratio on the failure process and patterns were analyzed, and the load-displacement hysteretic loops and skeleton curves are obtained.Based on the experimental results, the mechanical properties of the joints such as the load bearing capacity, ductility, energy dissipation, and the stiffness degeneration are studied.It is shown that the hysteretic hoops of the steel reinforced concrete Tshaped column-beam joints are plump.The joints have high bearing capacity, good ductility and energy dissipation capacity, which perform excellent seismic behaviors.%通过对9个型钢混凝土(SRC)异形柱框架边节点进行低周反复加载试验,观察了不同配钢形式、不同轴压比条件下SRC异形柱框架边节点的受力过程及破坏形态,得出了SRC异形柱框架边节点的荷载一位移滞回曲线和骨架曲线.根据试验结果,分析了节点承载力、延性、耗能以及刚度退化等性能.研究表明,SRC异形柱框架边节点的滞回曲线比较饱满,承载力高,耗能能力强,位移延性系数平均值可达到3.60,具有较好的抗震性能.

  11. Fire response of composite columns subject to sway

    DEFF Research Database (Denmark)

    Virdi, Kuldeep

    conditions is adequately covered in the relevant standard, Eurocode 4, simplified design of unbraced composite columns for the fire limit state has not been included. Recognising this, a collaborative research project was undertaken with funding from the Research Fund for Coal and Steel. The paper describes......Composite columns, using profiled steel sections encased in concrete or steel tubes filled with concrete, are increasingly used in practice taking advantage of speed of erection as well as offering cost-effective solutions. While the design of braced and unbraced composite columns under ambient...... the scope of the project which covered control tests under ambient conditions, carried out by the author while at City University London. Other aspects covered in the project included fire tests carried out by CTICM in France, on isolated columns and on two frames designed by Leibniz Universität Hannover...

  12. 复式钢管混凝土柱与H形钢梁连接节点抗震性能试验研究%Experimental study on seismic behavior of connection between composite CFST column and H-shaped steel beam

    Institute of Scientific and Technical Information of China (English)

    张玉芬; 张冬芳; 赵均海

    2013-01-01

    Learned from the vertical stiffener joint of square concrete filled steel tube (CFST) column,one new connection between composite CFST column and H-shaped steel beam was studied by test.This connection consists of vertical stiffeners connecting the beam flange to the column flange,meanwhile anchorage plate is groove welded on inner steel tube,coming through the outer steel tube,and welded and bolted connected with the steel beam web.Seven joint specimens were tested under cyclic loads to investigate the seismic behavior of composite connections.Based on the experiments,the failure process and feature of each specimen were described and hysteretic loops,loadcarrying capacity,ductility,stiffness degradation,strength degradation and energy dissipation capacity,etc.,were studied.The results show that failure modes of the tested specimens are basically the same:steel of the horizontal end plate yields first and plastic hinges form afterwards; the connections with ribbed anchorage plate can reach a higher load-bearing and deformation capacity than the connections without ribs; the extension of the vertical stiffener can improve the initial stiffness of the joint,and it is also effective in moving the buckling zone away from the joint zone.The hysteretic characteristics of the connections is stable and the energy dissipation capacity,strength and ductility are sufficient.In the whole loading process,the stiffness degradation is obvious and bearing capacity degradation is slow,so the seismic performance of the proposed new type of connection is adequate to be applied in seismic areas.%借鉴方钢管混凝土柱-钢梁外肋环板节点形式,将非梁柱连接面的柱两侧外肋环板改为竖贴于柱侧的竖向肋板并伸出与梁翼缘焊接,同时设置锚固腹板,形成复式钢管混凝土柱与H形钢梁连接节点.通过7个梁柱组合体试件的低周反复荷载试验,分析各试件的破坏过程及特征,并对试件的滞回性能、承载力、延

  13. 高强冷弯薄壁型钢抱合箱形截面受压构件承载力试验研究%Load-carrying capacity of 550MPa high-strength cold-formed thin-walled steel built-up box section columns

    Institute of Scientific and Technical Information of China (English)

    李元齐; 姚行友; 沈祖炎; 王树坤; 刘翔

    2011-01-01

    由两个槽形截面构成的抱合箱形截面在超薄壁冷弯型钢结构中应用广泛,但关于其承载力的计算只是将单个构件的承载力简单地数学叠加,并没有相应公式来考虑单个槽形截面构件之间的相互加强.对40根高强冷弯薄壁型钢抱合箱形截面受压构件进行试验研究,考察其受力特性及破坏特征,包括轴压构件21个,绕弱轴偏心和绕强轴偏心构件共19个.试验研究结果表明:抱合箱形截面构件由于两个槽形截面试件的相互约束作用,实测承载力比按单根构件计算承载力叠加结果提高10%~20%左右.最后,在试验和理论分析的基础上,针对高强冷弯薄壁型钢抱合箱形截面受压构件极限承载力提出了一种建议计算方法,依照建议计算方法所得结果与试验结果吻合较好,且偏于安全,可供实际设计参考.%Built-up box section columns by two lipped channel sections are widely used in super thin-walled cold-formed steel structures.However, for their load-carrying capacities of built-up box section columns, usually a mathematical sum according to the load-carrying capacities of each channel section involved is utilized without any further consideration on the reinforcement between single channel sections.Load-carrying capacities and failure modes of 40 high-strength cold-formed thin-walled steel built-up box section columns have been studied, including 21 axially-compressed columns and 19 eccentrically-compressed columns subjected to bending moments along the weak axis and the strong axis respectively.The results show that, due to the interaction between two lipped channel columns connected by self-drilling screws, the ultimate load-carrying capacity of a built-up box section column is 10% to 20% higher than the sum of the ultimate load-carrying capacity of two single lipped channels loaded in the same way independently.Based on the tests and theoretical analysis, a proposed method to estimate

  14. Experimental study on seismic behavior of recycled-concrete-filled square steel tube columns under cyclic reversed loading%低周反复荷载下方钢管再生混凝土柱抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    孟二从; 苏益声; 陈朋朋; 但宇

    2015-01-01

    为研究方钢管再生混凝土柱的抗震性能,以再生粗骨料取代率为变化参数,设计制作了4根不同取代率的试件,对其进行拟静力试验,研究分析其破坏形态、滞回曲线、骨架曲线、延性、耗能能力、刚度退化等力学性能指标。研究结果表明:方钢管再生混凝土柱的破坏形态与方钢管普通混凝土柱相似,均为柱脚的鼓曲破坏;随着再生骨料取代率的增大,试件的极限承载力会有所减小,但减小幅度不大;再生粗骨料取代率对试件的延性、耗能性能、刚度退化则没有明显的影响。%In order to study the seismic behavior of recycled-aggregate-concrete-filled square steel tube columns, four specimens with different replacement rates were test under the cyclic reversed loading. The destruction pattern and hysteretic performance, the hysteretic curves, skeleton curve, ductility, energy dissipation and stiffness degradation were analyzed. Research findings indicate that the destruction mode of recycled-aggregate-concrete-filled square steel tube columns is similar to that of concrete-filled square steel tubular columns. With the increase of the replacement ratio, the ulti-mate bearing capacity and measured value of he will be reduced, but the reduction is very tiny. The replacement ratio of recycled aggregate has no obvious effect on the ductility, energy dissipation and stiffness degradation.

  15. Distortional buckling experiments on cold-formed thin-walled steel lipped channel columns with circle holes under axial compression%腹板开孔冷弯薄壁钢轴压构件畸变屈曲承载力试验研究

    Institute of Scientific and Technical Information of China (English)

    谭政; 姚行友; 汪洋; 石梦婷; 刘忠勇; 朱丽芳; 曾罗兰

    2015-01-01

    This paper aims to research the distortional buckling mode and load-carrying capacity of cold-formed thin-walled steel members with holes. Compression tests were conducted on 26 intermediate length columns with and without web holes. The comparison of ultimate strength between test results and calcu-lated results using Chinese code Technical code of cold-formed thin-wall steel structures GB50018-2002 and nonlinear finite element method are made. The calculated method for cold-formed thin-walled steel columns with web holes is proposed. The results show that the distortional buckling mode would usually occur for the intermediate length axial compression. The web holes have a little influence on the distortion-al buckling ultimate strength of columns. The ultimate strength can be predicted using a reduced effective area.%对26根屈服强度235MPa腹板开圆孔冷弯薄壁型卷边槽钢截面轴压构件进行畸变屈曲承载力试验研究,分析了构件屈曲模式和极限承载力,采用国家规范GB50018—2002《冷弯薄壁型钢结构技术规范》计算构件承载力、非线性有限元数值模拟结果与试验结果进行分析比较。在此基础上,对腹板开孔冷弯薄壁型钢截面轴压构件的承载力合理计算模式进行研究。结果表明,对于中等长度腹板开孔冷弯薄壁型钢截面轴压构件主要出现畸变屈曲模式;腹板开孔在对构件畸变屈曲稳定承载力有一定的降低作用,采用折减构件有效截面面积的方法可计算开孔构件的畸变屈曲稳定承载力。

  16. 多室式钢管混凝土T形中长柱轴压性能研究%Study on the properties of multi-cell T-shaped concrete-filled steel tubular intermediate long columns under axial load

    Institute of Scientific and Technical Information of China (English)

    屠永清; 刘林林; 叶英华

    2012-01-01

    为了实现对多室式钢管混凝土T形柱轴压稳定性能的研究,进行6个中长柱试件及4个短柱对照试件的轴压试验,重点考察前者的破坏形态、荷载-变形关系及截面尺寸对承载力的影响。试验结果表明,中长柱的力学行为与短柱有较大不同,其破坏属于整体弯曲破坏,增大腹板高度对承载能力会产生有利影响。同时,将改进Mander模型后所得的混凝土本构关系引入有限元软件ABAQUS中,对试验进行了有限元模拟,其结果与试验结果吻合较好。在试验及有限元分析的基础上确定了中长柱与短柱之间的界限长细比,并对这一新型结构柱稳定承载力的计算方法进行了探讨,给出可供实际应用参考的计算公式。%In order to acquire the stability properties of multi-cell T-shaped concrete-filled steel tubular (MT-CFST) columns, axial compressive experiments of 6 intermediate long specimens and 4 stub specimens were presented. The failure modes, relationships between axial load and deformation and the effects of cross section dimensions on the bearing capacities of the specimens were investigated. It is demonstrated that the mechanical behaviors of MT-CFST middle long columns are different from stub columns. Their ultimate failure modes belong to buckling failure and the enhancement of web height could enhance the bearing capacities. A constitutive relationship of the concrete core is suggested by modifying Mander' s concrete model. Finite element analysis of the specimens is carried using ABAQUS and the calculation results are in good agreement with the experimental results. Based on the experiment and finite element analysis, the slenderness ratio limit between intermediate long columns and stub columns is suggested and subsequently a simplified formula for stable bearing capacities of MT-CFST columns is proposed.

  17. Modeling Stone Columns

    Directory of Open Access Journals (Sweden)

    Jorge Castro

    2017-07-01

    Full Text Available This paper reviews the main modeling techniques for stone columns, both ordinary stone columns and geosynthetic-encased stone columns. The paper tries to encompass the more recent advances and recommendations in the topic. Regarding the geometrical model, the main options are the “unit cell”, longitudinal gravel trenches in plane strain conditions, cylindrical rings of gravel in axial symmetry conditions, equivalent homogeneous soil with improved properties and three-dimensional models, either a full three-dimensional model or just a three-dimensional row or slice of columns. Some guidelines for obtaining these simplified geometrical models are provided and the particular case of groups of columns under footings is also analyzed. For the latter case, there is a column critical length that is around twice the footing width for non-encased columns in a homogeneous soft soil. In the literature, the column critical length is sometimes given as a function of the column length, which leads to some disparities in its value. Here it is shown that the column critical length mainly depends on the footing dimensions. Some other features related with column modeling are also briefly presented, such as the influence of column installation. Finally, some guidance and recommendations are provided on parameter selection for the study of stone columns.

  18. Modeling Stone Columns

    Science.gov (United States)

    2017-01-01

    This paper reviews the main modeling techniques for stone columns, both ordinary stone columns and geosynthetic-encased stone columns. The paper tries to encompass the more recent advances and recommendations in the topic. Regarding the geometrical model, the main options are the “unit cell”, longitudinal gravel trenches in plane strain conditions, cylindrical rings of gravel in axial symmetry conditions, equivalent homogeneous soil with improved properties and three-dimensional models, either a full three-dimensional model or just a three-dimensional row or slice of columns. Some guidelines for obtaining these simplified geometrical models are provided and the particular case of groups of columns under footings is also analyzed. For the latter case, there is a column critical length that is around twice the footing width for non-encased columns in a homogeneous soft soil. In the literature, the column critical length is sometimes given as a function of the column length, which leads to some disparities in its value. Here it is shown that the column critical length mainly depends on the footing dimensions. Some other features related with column modeling are also briefly presented, such as the influence of column installation. Finally, some guidance and recommendations are provided on parameter selection for the study of stone columns. PMID:28773146

  19. Effect of weld on design of steel moment-resisting connection reinforced with steel plates

    Institute of Scientific and Technical Information of China (English)

    CHEN Peng; LI Yong

    2005-01-01

    The foreign experimental and FEM research of steel moment-resisting connection reinforced with steel plates are introduced. The effect of weld on the connection design is studied in two ways including weld detail and geometrical detail of steel plates contrast to the reference drawing of connection design in China. The research shows that the weld plays an important role in the design of connections. The welds connecting reinforced plates and beam/ column flange and the plate geometry have direct influence on the performance of the connections reinforced with plates. The study is helpful to the application of design of steel moment-resisting connection with steel plates.

  20. Behaviour of High Strength Steel Endplate Connections in Fire and after Fire

    NARCIS (Netherlands)

    Qiang, X.

    2013-01-01

    The aim of this research is to reveal more information and understanding on behaviour and failure mechanisms of high strength steel endplate connections (combining high strength steel endplates with either mild steel or high strength steel beams and columns in endplate connections) in fire and after

  1. Behaviour of High Strength Steel Endplate Connections in Fire and after Fire

    NARCIS (Netherlands)

    Qiang, X.

    2013-01-01

    The aim of this research is to reveal more information and understanding on behaviour and failure mechanisms of high strength steel endplate connections (combining high strength steel endplates with either mild steel or high strength steel beams and columns in endplate connections) in fire and after

  2. COMPARISON OF EIGENMODE-BASED AND RANDOM FIELD-BASED IMPERFECTION MODELING FOR THE STOCHASTIC BUCKLING ANALYSIS OF I-SECTION BEAM–COLUMNS

    KAUST Repository

    STAVREV, A.

    2013-03-01

    The uncertainty of geometric imperfections in a series of nominally equal I-beams leads to a variability of corresponding buckling loads. Its analysis requires a stochastic imperfection model, which can be derived either by the simple variation of the critical eigenmode with a scalar random variable, or with the help of the more advanced theory of random fields. The present paper first provides a concise review of the two different modeling approaches, covering theoretical background, assumptions and calibration, and illustrates their integration into commercial finite element software to conduct stochastic buckling analyses with the Monte-Carlo method. The stochastic buckling behavior of an example beam is then simulated with both stochastic models, calibrated from corresponding imperfection measurements. The simulation results show that for different load cases, the response statistics of the buckling load obtained with the eigenmode-based and the random field-based models agree very well. A comparison of our simulation results with corresponding Eurocode 3 limit loads indicates that the design standard is very conservative for compression dominated load cases. © 2013 World Scientific Publishing Company.

  3. Fire-induced collapses of steel structures

    DEFF Research Database (Denmark)

    Dondera, Alexandru; Giuliani, Luisa

    Single-story steel buildings such as car parks and industrial halls are often characterised by stiff beams and flexible columns and may experience an outward (sway) collapse during a fire, endangering people and properties outside the building. It is therefore a current interest of the research...... on the beam. By means of those tables, a simple method for the assessment and the countermeasure of unsafe collapse mode of single-story steel buildings can be derived....... to investigate the collapse behaviour of single-story steel frames and identify relevant structural characteristics that influence the collapse mode. In this paper, a parametric study on the collapse a steel beam-column assembly with beam hinged connection and fixed column support is carried out under...

  4. 基于可持续性的冷弯型钢组合异形钢管混凝土柱框架-隅撑支撑结构%Sustainable knee braced frame with concrete filled cold-formed steel tube shaped columns

    Institute of Scientific and Technical Information of China (English)

    李成玉; 郭耀杰; 赵峰; 肖良丽; 吴东平

    2013-01-01

    Due to the shortage of land supply and rapid increase in population, the construction of tall buildings in cities has been expanding dramatically in the twenty-first century that improves people's ways of living. However, tall buildings involve problems such as huge energy cost of construction and the lack of aseismic ability. To avoid such shortcomings, with the good loading capacity, economical material cost and relatively small cross-section size, concrete filled cold-form steel tube shaped columns are adopted as an ideal structure component for high-rise buildings. Furthermore, the scientific double aseismic design of concrete filled cold-form steel tube shaped columns could develop adequate aseismic ability of the overall structure. In this proposed research, the series-parallel energy model clarifies the concepts of double aseismic designed structure and double aseismic defense; so as to provide guidelines for development of aseismic defense.%冷弯钢管混凝土异形柱具有承载能力高、耗材少及得房率高的优势,结合隅撑支撑框架体系及双侧板节点将其应用于高层结构中具有巨大的减量化潜力;面对随机性的地震动,科学设置双重可控防线是积极的应对策略,建立的串并联能量模型厘清了双重抗震结构体系与双重抗震防线的概念区别,为构建双重抗震防线提供了依据.

  5. Comparison of Limiting Width-Thickness Ratios of Steel Columns in Sino-foreign Seismic Design Codes%中外抗震设计规范关于钢柱板件宽厚比限值的比较

    Institute of Scientific and Technical Information of China (English)

    邓椿森; 施刚; 张勇; 王元清; 石永久

    2011-01-01

    板件宽厚比对钢结构的抗震性能有着重要影响,同时也是影响钢结构用钢量的一项重要指标,对钢结构的安全性和经济性均有着很重要的意义.目前国内已有不少文献认为我国现行抗震设计规范对梁柱截面板件宽厚比限值的规定尚不够严谨和完善,并对此提出了设计建议.结合中国抗震规范GB50011—2001、美国钢结构抗震规范ANSI/AISC 341—05、日本抗震规范BCJ和欧洲抗震规范Eurocode 8的相关规定,比较研究了中外抗震设计规范对工形截面和箱形截面钢柱板件宽厚比限值规定的异同,分析了中国抗震规范GB50011—2001关于钢柱板件宽厚比限值的合理性,为相关设计和研究提供了参考.%The limiting width-thickness ratio plays an important role in steel structures' safety and economy,as it not only has a significant influence on steel structures' seismic performance,but also is an important index of steel consumption for steel structures.At present,many domestic research results show that the limiting width-thickness ratios in our country's seismic design code are not adequate or reasonable and have presented corresponding design recommendation.The limiting width-thickness ratios in the related Chinese code GB50011—2001,American code ANSI/AISC 341—05,Japanese code BCJ and European code Eurocode 8 are compared and analyzed,which provides a reference for the relevant steel structure design and research.

  6. Experimental Research on New Type of Concrete-filled Steel Tubular Column Joint to RC Beam%新型钢管混凝土梁柱节点试验研究

    Institute of Scientific and Technical Information of China (English)

    陈玉泉; 张倩; 薛玉丽; 雷冬

    2013-01-01

    提出了一种新型的开大孔钢筋贯通式钢管混凝土节点,该新型节点形式与已应用到工程中的开小孔钢筋贯通式节点相比,具有施工方便的优点.建立了介于这种新节点与传统开小孔节点之间的过渡形式:开大孔加强式钢筋贯通的钢管混凝土节点.并通过对三种节点低周反复循环加载的试验研究,得到如下结论:新型开大孔式节点位移延性、耗能能力比较理想,抗震性能良好,符合抗震设计的要求.在该新型节点处设加强环和加劲肋能够显著提高节点的整体性与延性.研究结果可以为其在工程中的应用提供有价值的参考.%A new type of connection between concrete-filled steel bar and concrete frame beam with steel bar run-through joint was put forward according to the present joints. Big holes were cut in the steel tubular wall of core area of the joint. Compared with the joint which small holes were set in the steel tubular wall for steel bar running through, the new type joint was more easily to be constructed. And a transient joint was made to characterize with big holes and strengthening ring and stiffing ribs. Low cycle fatigue tests were implemented to analysis these three joints and the following conclusions were given; the displacement ductility and the ability of energy dissipation of this new type joint are more ideal and seismic behavior is better which all satisfied the requirement of the structural seismic design. The stiffening ring and stiffing ribs fixed on the joint both can improve its integrity and ductility significantly. Research results can provide theoretical and experimental reference to the engineering application.

  7. Behavior of reinforced concrete columns strenghtened by partial jacketing

    Directory of Open Access Journals (Sweden)

    D. B. FERREIRA

    Full Text Available This article presents the study of reinforced concrete columns strengthened using a partial jacket consisting of a 35mm self-compacting concrete layer added to its most compressed face and tested in combined compression and uniaxial bending until rupture. Wedge bolt connectors were used to increase bond at the interface between the two concrete layers of different ages. Seven 2000 mm long columns were tested. Two columns were cast monolithically and named PO (original column e PR (reference column. The other five columns were strengthened using a new 35 mm thick self-compacting concrete layer attached to the column face subjected to highest compressive stresses. Column PO had a 120mm by 250 mm rectangular cross section and other columns had a 155 mm by 250mm cross section after the strengthening procedure. Results show that the ultimate resistance of the strengthened columns was more than three times the ultimate resistance of the original column PO, indicating the effectiveness of the strengthening procedure. Detachment of the new concrete layer with concrete crushing and steel yielding occurred in the strengthened columns.

  8. ANALYSIS OF BEARING CAPACITY OF DOUBLE COLD-FORMED THIN-WALLED C STEEL BACK-TO-BACK COMPOSITE COLUMN WITH PLATE COUPLED%带垫板的双肢背靠背C型钢组合柱承载力分析

    Institute of Scientific and Technical Information of China (English)

    陈明; 芦文文; 刘凯

    2014-01-01

    According to the composite column of double cold-formed thin-walled C steel back to back connected with gusset plate, the test and finite element analysis were carried out to study the stability bearing capacity and failure modes of the specimen under eccentric loading.The elements such as slenderness ratio, gusset plate thickness and gusset plate spacing were discussed , which produced the impacts to composite column ’ s bearing capacity, the relationship between stiffness and axial loading, and the curves of M-φof eccentricity.The results revealed that before the overall instability the local-buckling was occurred, the failure modes were belonging to the in-plane-flexural buckling.The major factors are slenderness ratio, eccentricity and gusset plate spacing which effected the mechanical behavior, while the gusset plate thickness has no obvious impact.In the end, the calculation method of the bearing capacity of the cold-formed thin-walled column was compared with that in“Technical Code of Cold-Formed Thin-Walled Section Steel Structures” ( GB 50018-2002 ) , some suggestions based on the type of composite section column calculation were put forward , and the bearing capacity correction coefficient of the steel composite columns was given .%针对带垫板的双肢背靠背C型钢组合柱,通过试验和有限元模拟分析,研究该类型组合柱在偏心荷载作用下的受力特性,就偏心距、长细比、垫板厚度和间距等参数对组合柱承载力、刚度与轴向荷载的关系和M-φ曲线的影响进行讨论。结果表明:C型钢腹板和受压翼缘在整体失稳之前出现了严重的局部屈曲,组合柱的破坏模式均为弯矩作用平面内的弯曲失稳。长细比、偏心距和垫板间距是影响组合柱受力性能的主要因素,垫板厚度的影响有限。最后与规范GB 50018-2002《冷弯薄壁型钢结构技术规范》规定的柱承载力的计算方法进行对比,对该类组合柱的

  9. Column Liquid Chromatography.

    Science.gov (United States)

    Majors, Ronald E.; And Others

    1984-01-01

    Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

  10. Experimental study and mechanical behavior analysis of recycled aggregate concrete filled steel tubular long columns under axial compression%钢管再生混凝土轴压长柱试验研究及力学性能分析

    Institute of Scientific and Technical Information of China (English)

    张向冈; 陈宗平; 薛建阳; 苏益声; 范杰

    2012-01-01

    Axial static monotonic loading test was carried out on 5 recycled aggregate concrete filled cycled steel tubular long columns and 5 recycled aggregate concrete filled square steel tubular tong columns. The test parameters include section form, replacement rate of recycled coarse aggregate and slenderness ratio. The whole loading process and failure modes were observed. The important characteristic data were captured such as the yield strain, the peak deformation, the bearing capacity and so on. A series of important curves about load-deformation, load-strain and axial stiffness- deformation were plotted. The influences of the test parameters on the bearing capacity were analyzed. The bearing capacity and axial stiffness of two section types under the serviceability limit state were calculated by some related procedures. It is shown that the loading process of recycled aggregate concrete filled steel tubular long columns under axial compression is made up of elastic stage, yield stage and failure stage. The failure modes are mainly strength failure and failure of elasto-plastic instability. The influence of replacement rate on the bearing capacity is little. The influence of slenderness ratio on the bearing capacity of recycled aggregate concrete filled cycled steel circular tubular long columns is great. When the slenderness ratio increases, the bearing capacity will decrease. However, the influence of slenderness ratio on the bearing capacity of recycled aggregate concrete filled square steeltubular long columns is little. Based on the calculation resuh, the design suggestion is provided about the bearing capacity and axial stiffness of recycled aggregate concrete filled steel tubular long columns under axial compression. The research results can provide reference for further research and application of recycled aggregate concrete filled steel tubular structure.%设计5个圆钢管再生混凝土长柱和5个方钢管再生混凝土长柱,对其进行轴压静力

  11. Steel making

    CERN Document Server

    Chakrabarti, A K

    2014-01-01

    "Steel Making" is designed to give students a strong grounding in the theory and state-of-the-art practice of production of steels. This book is primarily focused to meet the needs of undergraduate metallurgical students and candidates for associate membership examinations of professional bodies (AMIIM, AMIE). Besides, for all engineering professionals working in steel plants who need to understand the basic principles of steel making, the text provides a sound introduction to the subject.Beginning with a brief introduction to the historical perspective and current status of steel making together with the reasons for obsolescence of Bessemer converter and open hearth processes, the book moves on to: elaborate the physiochemical principles involved in steel making; explain the operational principles and practices of the modern processes of primary steel making (LD converter, Q-BOP process, and electric furnace process); provide a summary of the developments in secondary refining of steels; discuss principles a...

  12. 方CFRP-钢管混凝土(S-CFRP-CFST)压弯构件滞回性能试验研究%EXPERIMENTAL STUDY ON HYSTERETIC BEHAVIOR OF THE CONCRETE FILLED SQUARE CFRP-STEEL TUBULAR (S-CFRP-CFST)BEAM-COLUMN

    Institute of Scientific and Technical Information of China (English)

    闫煦; 周博

    2013-01-01

    Overall 8 pieces of specimens were experimentally investigated to study the hysteretic behaviors of the concrete filled square CFRP-steel tubular (S-CFRP-CFST) beam-column.The test results indicated that the longitudinal CFRP can provide strengthening effect for the concrete filled square steel tube (S-CFST) effectively,and the load bearing capacity of the specimen is enhanced.Based on the analysis of the experimental results,it shows that the axial compression ratio can enhance the flexural bearing strength of the specimen,also,the steel tube and the CFRP material can work concurrently both in the longitudinal and transverse directions.The computational result indicates that there are some strength degradation for all of the specimens.The axial compression ratio and the strengthening factor of longitudinal CFRP can enhance the stiffness of members,and they can also delay the stiffness degradation.However,the axial compression ratio is beneficial to aseismic behaviors within a certain range.%进行了8个方CFRP-钢管混凝土压弯构件的滞回性能试验.试验结果表明,纵向CFRP对方钢管混凝土有很好的增强作用,可以提高试件的承载力.对试验结果的分析表明,轴压比可以提高试件的抗弯承载力,钢管和CFRP管的变形协调一致.计算表明:试件强度均有一定退化;轴压比和纵向CFRP增强系数的增大可以提高试件的刚度,同时减缓刚度退化;轴压比在一定范围内有利于试件的抗震.

  13. Experimental Study on CFRP Strengthened Cold Formed Channel Columns

    Directory of Open Access Journals (Sweden)

    Sreedhar Kalavagunta

    2013-09-01

    Full Text Available Cold-formed steel members usually display local-global buckling interaction which strongly effects the structural strength of columns. Through strengthening web of the members this buckling can be controlled to some extent. In this investigation, Carbon Fibre Reinforced Polymers (CFRP is used for strengthening cold formed steel channel member. This paper presents compression tests of cold-formed plain and CFRP strengthened steel channel section columns. This paper also proposes a design method based on Direct Strength Method provisions specified in American Iron and Steel Institute (AISI, for determining the axial compression strength. Results obtained from the proposed design method are compared with experimental test data and are found to be in good agreement.

  14. Steel Spring

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Tarnished Hebei Iron and Steel Group regains chance to shine A lthough it is too early to tell whether the steel-making sector has emerged [from its gloom, a big divide is openling between China’s large and small producers. While most of the marginal players are still reeling from a market contagion, steel titans like the Shanghai-based Baosteel

  15. 76 FR 73986 - Redelegation of Administrative Authority for Title I, Section 109 of the Housing and Community...

    Science.gov (United States)

    2011-11-29

    ... URBAN DEVELOPMENT Redelegation of Administrative Authority for Title I, Section 109 of the Housing and... Opportunity, HUD. ACTION: Notice of redelegation of authority. SUMMARY: The Assistant Secretary for Fair Housing and Equal Opportunity (FHEO) supersedes all prior redelegations of authority from the...

  16. Comparison and experimental analysis of the seismic performance of steel rein-forced concrete exterior frame and middle frame with special-shaped columns%型钢混凝土异形柱中框架和边框架抗震性能试验对比分析

    Institute of Scientific and Technical Information of China (English)

    薛建阳; 杨青峰; 刘祖强; 赵鸿铁; 周超锋

    2016-01-01

    In order to compare the seismic performance of steel reinforced concrete (SRC) frames with special-shaped columns at different spatial locations, two models, an exterior frame and a middle frame, were tested under low cyclic reversed loading. The failure pattern were obtained and the mechanical behaviors such as hysteretic loops, skeleton curves, carrying capacity, ductility, energy dissipation, stiffness and shape steel strain distribution were analyzed. Test results show that SRC frame with special-shaped columns satisfies the seismic design principle of “strong column and weak beam, strong joint and weak member”, the hysteretic loops are plump, the ductility is good and the energy dissipation is strong. Compared with the exterior frame, the middle frame has higher carrying capacity, stronger energy dissipation and larger initial stiffness, but the ductility and rate of stiffness degradation is not as great.%为对比空间位置不同的型钢混凝土(SRC)异形柱框架的抗震性能,各设计1榀边框架和中框架进行低周反复加载试验,获得其破坏形态,分析其滞回曲线、骨架曲线、承载力、延性、耗能能力、刚度和型钢应变等特性。结果表明:SRC异形柱框架符合“强柱弱梁、强构件弱节点”的抗震设计要求,滞回曲线饱满,延性好,耗能能力强;与边框架相比,SRC异形柱中框架具有更高的承载力、更强的耗能能力和更大的初始刚度,但两者的延性比较接近,刚度退化速度相差不大。

  17. Overall buckling behavior of Q460 high strength steel welded box section columns under axial compression%Q460高强钢焊接箱形截面轴压构件整体稳定性能研究

    Institute of Scientific and Technical Information of China (English)

    班慧勇; 施刚; 石永久; 王元清

    2013-01-01

    为研究高强度钢材轴心受压钢柱的整体稳定性能,对5个国产Q460钢材焊接箱形截面柱进行了轴心受压试验研究.试验对试件的几何初弯曲、荷载初偏心以及截面的纵向残余应力分布均进行了测量.基于试验结果,分析了该类钢柱的失稳破坏形态和整体稳定承载力,建立了有限元分析模型并对试验结果进行模拟计算.研究结果表明:试件破坏模态均为整体弯曲失稳形态,大部分试件稳定承载力高于规范设计值;有限元分析模型能够准确地考虑几何初始缺陷和残余应力的影响,计算结果与试验结果吻合良好;通过与国内外钢结构设计规范的对比,提出了国产Q460高强钢焊接箱形截面轴压构件整体稳定设计的建议方法,即可以统一采用我国或欧洲规范的b类曲线进行设计,而不需要按板件宽厚比大小进行分类.%In order to investigate the overall buckling behavior of Q460 high strength steel columns under axial compression, 5 full-scale specimens were tested and the initial bending, loading eccentricity and sectional residual stress were also measured. Based on the experimental results, the failure mode and buckling capacity were clarified, and a finite element model was established to simulate the overall buckling behavior of such columns. It is found that the finite element model can well describe the effects caused by both initial geometric imperfections and residual stresses, and the calculated results through finite element analysis have a good agreement with experimental results. The validated model was further implemented for a large number of parametric analysis, and the calculated results were compared with different steel structure design codes. The design method for the overall buckling behavior of Q460 high strength steel welded box section columns was suggested, i. e. the column curve b in both GB 50017-2003 and Eurocode 3 can be employed to design such structural

  18. HYSTERETIC BEHAVIOR STUDY ON CONNECTION OF PEC COLUMNS-STEEL BEAM WITH END PLATES AND PRETENSION HIGH-STRENGTH PENETRATING BOLTS%薄钢板PEC柱-钢梁端板对拉螺栓连接滞回性能试验研究

    Institute of Scientific and Technical Information of China (English)

    马吉; 方有珍; 陆承铎; 韩昌标; 孙国华

    2013-01-01

    The PEC column fabricated with thin-walled built-up section-steel beam connections with reduced cross sections,end plates and pretension high-strength penetrating bolts,the column layout and reduced cross-section location were taken as the design parameters,and 3 specimens were designed and fabricated by 1 ∶ 0.625 scale,which represented the middle joints.The test of the specimens was conducted under lateral cyclic loading in the column strong or weak axis,the test process was observed and the hysteretic curves were obtained.Based on the test results,the joints' global responses were analyzed,including the hysteretic behaviors,degradation of strength and flexural stiffness,energy-dissipation capacity,the ductility property and the failure mode.The conclusion showed that the specimens exhibited various degrees of self-centering functions,sound ductility and energy-dissipation capacity; the failure mode formed primary induced by yielding in the reduced cross-section or near the welding position of a steel beam.The study provides an experimental basis for amending the specification and engineering practice adopting the structure comprised of PEC columns-steel beams.%薄钢板组合截面PEC柱-钢梁连接中节点,采取工字梁端截面削弱、端板与预拉对穿高强螺栓的连接方式,考虑组合柱布置与梁削弱截面位置变化作为设计参数,对3个PEC柱-削弱梁、短端板对穿螺栓连接中节点1∶0.625缩尺模型进行低周反复荷载下的滞回性能试验.观察各个试件试验中的破坏过程,通过实测数据分析,得到了该类框架连接节点的滞回性能、强度与转动刚度退化、延性与耗能能力和破坏模式.结果表明:由于预拉对穿螺栓的设置,所有试件均表现出不同程度的自复位效果和良好的转动与耗能能力;节点的破坏模式为钢梁削弱截面或连接部位附近截面屈服.研究进一步丰富了PEC柱-钢梁连接的研究成果,为PEC柱-钢梁组合

  19. 基于梁柱节点性能的钢-竹组合框架结构地震反应分析%Seismic Response Analysis of Bamboo-steel Composite Frame Structure Based on Performance of Beam-column Joints

    Institute of Scientific and Technical Information of China (English)

    李玉顺; 何佳伟; 张家亮; 许科科; 杜永飞

    2016-01-01

    为研究钢‐竹组合框架中连接钢‐竹组合柱和钢‐竹组合梁的节点性能,通过拟静力试验得到不同参数下半刚性节点的弯矩与转角的多项式拟合关系,在此基础上建立了6榀2层钢‐竹组合框架的数值模型,进行了地震作用下的有限元分析,探讨了节点对钢‐竹组合结构抗震性能的影响。为充分考虑节点的半刚性特性,采用Combin39非线性弹簧单元模拟节点,研究了6榀框架在不同情况下的最大水平位移与最大基底剪力、水平位移与基底剪力时程曲线和滞回曲线等指标。结果表明:钢‐竹组合框架滞回曲线饱满,抗震性能突出,提高节点处螺拴的强度和设置加劲肋对提高钢‐竹组合框架的抗震性能有明显效果,节点的构建因素对框架的抗震性能有显著影响。%In order to study the performance of bamboo‐steel composite frame joint which connected bamboo‐steel composite column and bamboo‐steel composite beam ,moment and angle polynomial fitting relationship of semi‐rigid joints under different parameters were obtained by quasi‐static test .Based on this ,the numerical models of six pieces of two‐layer bamboo‐steel composite frame were built ,the finite element analysis under seismic action were carried out ,and the influence of joints on the seismic performance of bamboo‐steel structure were discussed .In order to fully consider the characteristics of semi‐rigid joints ,Combin39 nonlinear spring element was used to simulate joint ,the maximum displacement and base shear force curves ,displacement and base shear time history curves and hysteresis curves of six frames under different situations were studied .The results show that the hysteresis curves of bamboo‐steel composite frame is plump , the seismic performance is outstanding ,improvements of the bolt strength in the joint and the stiffeners set have obvious influences on improvement of the

  20. Spiral multicapillary columns

    Science.gov (United States)

    Efimenko, A. P.; Naumenko, I. I.; Soboleva, V. K.

    2008-08-01

    It was shown in a theoretical study and confirmed by experiment that a spiral multicapillary column had maximum efficiency if the bunch of capillaries was additionally coiled around its longitudinal axis to produce an integral number of coils. This technique made it possible to manufacture gas-chromatographic columns with performance as high as 12 to 16 thousand theoretical plates. These columns can find various applications, especially if quick separation is required.

  1. The static strenght of i-beam to circular hollow section column connections

    NARCIS (Netherlands)

    De Winkel, G.D.

    1998-01-01

    Semi-rigid connections between I-section beams and tubular columns can be used economically for buildings and offshore structures. The lack of stiffening plates allows the fabrication of these connections in a cost effective way. Furthermore, by taking into account the connection strength and stiffn

  2. Parametric analyse of stress intensity factors of beam-to-column web connections in steel moment frames%腹板连接节点焊缝应力强度因子的参数分析

    Institute of Scientific and Technical Information of China (English)

    刘洪波; 翟长海; 谢礼立; 邵永松

    2011-01-01

    A method that combined fracture mechanics and finite element was presented to quantify the variation of stress intensity factor to weld root flaw sizes in beam-to-column web connections with extended beam flange plates. Fracture toughness demands of web connections with extended beam flange plates were evaluated in terms of the mode I stress intensity factor. The stress intensity factor was calculated through a J-integral approach. The connection geometry was separately investigated in terms of the beam and column properties by finite element method. The influences of the length of beam and the length of column on the stress intensity factor were analyzed. The fracture toughness demands for the flaw on the top of the beam flange and for the bottom surface were studied, respectively. Finally, formulas for stress intensity factor were derived by orthogonal design and the results of finite element analysis. Results show that the likelihood of top flange fractures is smaller than that of bottom flange fracture. Stress intensity factor increases with the increase of beam parameters and reduces with the increase of column parameters.%为定量的确定荷载作用下钢框架结构延长翼缘连接板梁柱腹板连接节点焊缝应力强度因子的大小,采用断裂力学与有限元积分相结合的方法,研究腹板连接节点的断裂性能.判断延长翼缘连接板腹板连接节点焊缝开裂的依据是Ⅰ型应力强度因子,应力强度因子可以通过有限元计算J积分的方法求得.通过有限元计算分析了初始裂纹深度、梁截面尺寸、柱截面尺寸和梁柱长度对延长翼缘连接板腹板连接节点焊缝应力强度因子的影响.采用正交设计法进行研究方案设计,根据有限元分析结果归纳出应力强度因子计算公式.研究结果表明:延长翼缘连接板腹板连接节点梁下翼缘焊缝比上翼缘更容易开裂,应力强度因子随梁截面参数的增大而增大,随柱截面参数的增大而减小.

  3. Tool steels

    DEFF Research Database (Denmark)

    Højerslev, C.

    2001-01-01

    On designing a tool steel, its composition and heat treatment parameters are chosen to provide a hardened and tempered martensitic matrix in which carbides are evenly distributed. In this condition the matrix has an optimum combination of hardness andtoughness, the primary carbides provide...... resistance against abrasive wear and secondary carbides (if any) increase the resistance against plastic deformation. Tool steels are alloyed with carbide forming elements (Typically: vanadium, tungsten, molybdenumand chromium) furthermore some steel types contains cobalt. Addition of alloying elements...

  4. Experimental research and nonlinear FEA on seismic behavior of square concrete-filled tubular column to H-shape steel beam connection%矩形钢管混凝土柱-H型钢梁节点抗震性能试验研究及有限元分析

    Institute of Scientific and Technical Information of China (English)

    丁永君; 尚奎杰; 万方贵; 秦颖

    2012-01-01

    以天津泰达广场CBD工程A、B区超高层项目为背景,进行了不同连接方法的6个足尺矩形钢管混凝土柱-H型钢梁节点试件拟静力试验,分析了试件的破坏特征、承载力、延性、耗能能力、刚度退化、强度退化等性能。结果表明:在保证焊接及安装质量的前提下不同连接方法节点均具有较高的承载力及良好的抗震性能;在梁翼缘两侧焊接加强板有利于节点承载力的提高,矩形钢管中填充混凝土有利于减小节点核心区的剪切变形,提高节点的强度及刚度。利用ANSYS10.0软件对试件在循环荷载作用下的滞回性能进行非线性模拟计算,并将理论分析结果与试验结果进行对比。对比结果表明,非线性有限元分析得出荷载.位移曲线与试验结果吻合较好,矩形钢管混凝土柱-H型钢梁节点均具有良好的耗能能力。%Taking the project of the A and B area ultra-high-level building of TeDa square in Tianjin as background, cyclic loading tests on six full scale square CFT column to H-shape steel beam joint specimens containing four different kinds of joint of details were carried out. The basic situation and failure characteristics of all specimens were introduced. The bearing capacity, ductility and energy dissipation capacity, stiffness degradation and strength degradation of four kinds of joints were compared. Test results show that, if the quality of welding and installation can be ensured, all four kinds of joints have high bearing capacity and good seismic behavior. Welding reinforcing plates on both sides of the beam flange contributes to the joint bearing capacity. Filling concrete in the rectangular pipe is useful for reducing shear deformation and improving strength and rigidity of cores of beam-column joints. In addition, ANSYS 10. 0 was used to simulate the hysteretic behavior of the specimens and the nonlinear analysis was carried out. The results of

  5. DISTORTIONAL BUCKLING TEST AND CALCULATION METHOD OF LOAD-CARRYING CAPACITY OF COLD-FORMED THIN-WALLED STEEL LIPPED CHANNEL COLUMNS WITH CIRCLE HOLES IN WEB UNDER AXIAL COMPRESSION%腹板开圆孔冷弯卷边槽钢轴压构件畸变屈曲承载力试验及计算方法

    Institute of Scientific and Technical Information of China (English)

    姚行友; 郭彦利

    2016-01-01

    对26根屈服强度为235 MPa的腹板开孔和未开孔冷弯薄壁型钢截面轴压构件进行畸变屈曲承载力试验研究,分析构件的屈曲模式和极限承载力.将我国及北美相关规范计算的构件承载力以及非线性有限元数值模拟结果与试验结果进行分析比较,并对腹板开孔冷弯薄壁型钢截面轴压构件的承载力合理计算模式进行研究.结果表明:对于中等长度腹板开孔冷弯薄壁型钢截面轴压构件主要出现局部、畸变和整体屈曲的相关作用;腹板开孔对构件畸变屈曲稳定承载力有一定的降低作用;采用折减构件有效截面面积的修正方法可计算开孔构件的畸变屈曲稳定承载力;非线性有限元方法可用于腹板开孔冷弯薄壁型钢构件的屈曲模式和极限承载力的分析.%In order to research the distortional buckling mode and load-carrying capacity of cold-formed thin-walled steel members with holes, compression tests were conducted on 26 intermediate length columns with and without web holes.For each specimen, a shell finite element eigenbuckling analysis and nonlinear analysis were also conducted such that the influence of the hole on local, distortional, and global elastic buckling responses could also be got.The comparison of ultimate strength between test results and calculated results using relevant codes was made.The calculated method for cold-formed thin-walled steel columns with web holes was proposed.The results showed that the interaction of local buckling, distortional buckling, and overall buckling usually would occur in the intermediate length member under axial compression, and the web holes had a little influence on the elastic buckling strength and the distortional buckling ultimate strength of columns, the ultimate strength of the members with holes in web could be predicted using a reduced effective area, and the nonlinear finite element method could be used to analyse the buckling mode and

  6. JCE Feature Columns

    Science.gov (United States)

    Holmes, Jon L.

    1999-05-01

    The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using these links you can easily find abstracts of additional articles that are related by topic. Of course, JCE Online+ subscribers are then just one click away from the entire article. Finding related articles is easy because each feature column "site" contains links to the online abstracts of all the articles that have appeared in the column. In addition, you can find the mission statement for the column and the email link to the column editor that I mentioned above. At the discretion of its editor, a feature column site may contain additional resources. As an example, the Chemical Information Instructor column edited by Arleen Somerville will have a periodically updated bibliography of resources for teaching and using chemical information. Due to the increase in the number of these resources available on the WWW, it only makes sense to publish this information online so that you can get to these resources with a simple click of the mouse. We expect that there will soon be additional information and resources at several other feature column sites. Following in the footsteps of the Chemical Information Instructor, up-to-date bibliographies and links to related online resources can be made available. We hope to extend the online component of our feature columns with moderated online discussion forums. If you have a suggestion for an online resource you would like to see included, let the feature editor or JCE Online (jceonline@chem.wisc.edu) know about it. JCE Internet Features JCE Internet also has several feature columns: Chemical Education Resource Shelf, Conceptual Questions and Challenge Problems, Equipment Buyers Guide, Hal's Picks, Mathcad

  7. Glass-silicon column

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Conrad M.

    2003-12-30

    A glass-silicon column that can operate in temperature variations between room temperature and about 450.degree. C. The glass-silicon column includes large area glass, such as a thin Corning 7740 boron-silicate glass bonded to a silicon wafer, with an electrode embedded in or mounted on glass of the column, and with a self alignment silicon post/glass hole structure. The glass/silicon components are bonded, for example be anodic bonding. In one embodiment, the column includes two outer layers of silicon each bonded to an inner layer of glass, with an electrode imbedded between the layers of glass, and with at least one self alignment hole and post arrangement. The electrode functions as a column heater, and one glass/silicon component is provided with a number of flow channels adjacent the bonded surfaces.

  8. 考虑火灾全过程的钢管混凝土组合框架力学性能初步研究%Preliminary Research on Mechanical Behavior of Composite Frame with Concrete-filled Steel Tubular Columns after Exposure to Overall Stage of Fire

    Institute of Scientific and Technical Information of China (English)

    王景玄; 张鹏鹏; 王文达

    2012-01-01

    In order to simulate the real fire resistance in the projects, this paper presented a finite element model(FEM) of concrete-filled steel tubular(CFST) columns and composite beam single-story-single-span planar frame after exposure to overall stage of fire based on ABAQUS. The whole phases including loading at ambient, heating, cooling and post-fire, which followed the ISO-834 standard fire curve. The temperature model was established with the determinations of thermal parameters of steel and core concrete. The temperature distribution of CFST columns and composite beam was calculated using FEM. The mechanical behavior of CFST columns and composite beam frame working in entire stage of fire was discussed in this paper. The result shows that: The CFST composite frame still has high bearing capacity after exposure to overall stage of fire due to the heat absorption and the constraint function of reinforced concrete floor. The results of this paper can provide a basis for fire-damage assessment of composite beam frame with CFST columns.%为进一步研究真实火灾工况下钢管混凝土组合框架的抗火性能,基于有限元软件ABAQUS建立了单层单跨圆形钢管混凝土柱-组合梁平面框架经历火灾全过程的数值分析模型.通过合理选取热工参数,进行了组合框架在ISO-834标准升降温曲线下的热传分析,研究了组合框架钢管混凝土柱与组合梁截面温度场的变化规律;在热传模型的基础上,通过合理选取材料本构模型、单元类型、边界条件以及网格划分等,对经历常温加载、升温、降温以及火灾后的钢管混凝土柱-组合梁平面框架的力学性能进行初步探讨.结果表明,由于钢筋混凝土楼板在受火过程中的吸热与约束作用使组合框架在受火后仍具有较高承载力.该方法可进一步完善钢管混凝土结构抗火分析理论,也可供实际工程应用参考.

  9. 复材布约束有预压荷载的型钢混凝土矩形短柱轴压性能试验研究∗%EXPERIMENTAL STUDY OF THE AXIAL COMPRESSIVE PERFORMANCE OF PRELOADED STEEL REINFORCED CONCRETE RECTANGULAR SHORT COLUMNS CONFINED BY CARBON FIBER REINFORCED POLYMER LAMINATES

    Institute of Scientific and Technical Information of China (English)

    高鹏; 殷强; 王健; 宗文; 洪丽

    2016-01-01

    为研究碳纤维布约束型钢混凝土矩形短柱的轴心受压破坏机理和受力性能,对15个试件进行了轴向静力加载试验,考虑了碳纤维布层数和预压荷载水平两个参数。试验结果表明:所有的约束型钢混凝土柱均以碳纤维布断裂为破坏标志,破坏前有明显的预兆。施加在约束柱上的峰值荷载随碳纤维布层数增加而提高,包裹2层布提高了58�36%,3层提高了64�51%;预压荷载的存在会减弱碳纤维布对短柱的约束效果,且随着预压荷载水平的提高,布的有效拉应变不断减小,柱承载能力不断降低。最后建立了碳纤维布有效拉应变与预压荷载水平的关系式,提出了构件轴压承载能力计算式,计算结果与试验结果吻合良好。%In order to study the axial compressive behavior of preloaded steel reinforced concrete ( SRC) rectangular short columns confined by carbon fiber reinforced polymer ( CFRP) laminates, a total of 15 specimens were designed to conduct the experiment that considered two variables including preload level and CFRP layers. The experimental results indicated that all of the confined columns failed directly in the fracture of CFRP laminates, in which there was an obvious sign before the ultimate state. Compared with the unconfined SRC column, the peak load of the confined column with 2 layers of CFRP increased by 58�36%, while by 64�51% with 3 layers. In addition, the preload decreased the effectiveness of confinement, both of the working strain of CFRP and the peak load of columns decreased with the increasing of the preload level. The relationship between the effective circumferential strain of CFRP and preload level was proposed. The theoretical formula of the axial bearing capacities of preloaded SRC rectangular columns confined by CFRP was proposed, and the calculation results agreed well with the test results.

  10. 冷弯薄壁型钢开口三肢拼合立柱轴压性能有限元分析%Finite Element Analysis of Cold-formed Thin-walled Steel Three Open Limbs Built-up Columns Under Axial Compression

    Institute of Scientific and Technical Information of China (English)

    刘向斌; 周天华; 聂少锋; 吴函恒

    2011-01-01

    The finite element model involving materials nonlinearity, geometric nonlinearity and contact nonlinearity was established, the influences of slenderness ratios, screw connection spacings, maximum width-thickness ratios on cold-formed thin-walled steel three open limbs built-up columns under axial compression were analyzed by using ANSYS finite element program. Results show that the slenderness ratio has great influence on the bearing capacity of axial compression and the axial compression performance for class A, B section built-up columns, with the increase of the column slenderness ratio, the ultimate bearing capacity gradually decreases. For two class section built-up columns, when screw connection spacing has arranged 450,300,150 mm, the ultimate bearing capacity of axial compression and the rigidity are little affected. For the three different lengths to the two class section built-up columns, as different thicknesses of the basic component plates cause different width-thickness ratios of the section, the ultimate bearing capacity of axial compression and the rigidity are obviously affected. When length and thickness of class A, B section built-up columns are same, and the basic component web height is increasedfrom 89 mm to 140 mm, the ultimate bearing capacity of axial compression is not obviously improved.%建立了考虑材料、几何和接触非线性的有限元模型,利用ANSYS有限元程序分析了长细比、螺钉连接间距、截面板件最大宽厚比对冷弯薄壁型钢开口三肢拼合立柱轴压性能的影响.结果表明:立柱长细比对A、B两类截面拼合立柱轴压承载力和轴压性能有很大影响,随着立柱长细比的增大,立柱轴压极限承载力逐渐降低;当螺钉连接间距为450、300、150 mm时,A、B两类截面拼合立柱轴压极限承载力和刚度变化均不大;由于基本构件板材厚度不同引起截面板件最大宽厚比的不同,对A、B两类截面3种长度的拼合立柱的承

  11. 冷弯薄壁型钢钢板-螺栓梁柱节点的力学性能分析%Mechanical properties investigation of cold-formed steel beam-column joints with bolt-plate

    Institute of Scientific and Technical Information of China (English)

    杨娜; 钟延营

    2011-01-01

    The ANSYS software is used to investigate the influential factors of the static behavior of gusset plate-bolted connection. The influential factors of the connections of three kinds of width of beam-column web were studied, including bolt pitch, the thickness of gusset plate, and the thickness of web and the width of flange and so on. It is found that the width of beam-column web the thickness of gusset plate, the thickness of web are highly effective factors for the static behavior,while the bolt pitch and the width of flange do not affect the initial stiffness and the ultimate bearing capacity of the joints. Finally, design proposals of three sections form connections are demonstrated, the dynamic performance of three kinds of recommended connections have been preliminarily studied in this paper.%为了观察不同梁、柱截面尺寸冷弯薄壁型钢钢板-螺栓节点静力性能的影响因素,采用AN-SYS软件对连接进行非线性有限元分析,研究3种梁柱腹板的节点螺栓间距、连接板厚度、腹板厚度和翼缘宽度等因素对其连接性能的影响.结果表明,梁柱腹板宽度、连接板厚度、梁柱腹板厚度是影响该连接节点静力性能的有效因素,而改变螺栓间距、梁柱翼缘宽度对节点的初始刚度和极限承载力的影响都不明显.给出了3种截面形式节点的设计建议,并对节点滞回性能进行了初步探讨,提出了滞回性能指标分析结论.

  12. 钢管混凝土板柱结点抗侧移性能%Studies on the Lateral Load-Drift Capacity of Steel Pipe Column-Slab Connection

    Institute of Scientific and Technical Information of China (English)

    李志民; 段珊

    2014-01-01

    对新型钢管混凝土板柱节点的抗侧移性能进行了研究。结果表明,节点不论是在强弯弱冲还是在强冲弱弯的条件下节点的侧移能力均可以达到2%,节点有着良好的抗侧移能力,主要取决于托板的变形能力。节点附加弯矩小,节点按照铰接设计是成立的,其构造形式优于传统节点。%The load-drift functions of a new kind of slab-column connection were studied. The results show that the displacement of the joint can achieve 2% in conditions while shear strength or bending resistance is dominated. Its lateral displacement mainly depends on the deformability of the pallet. This kind of joint benefits in load transfer and its additional moment flexion is low. The structural forms are better than the traditional ones.

  13. Distillation Column Flooding Predictor

    Energy Technology Data Exchange (ETDEWEB)

    George E. Dzyacky

    2010-11-23

    The Flooding Predictor™ is a patented advanced control technology proven in research at the Separations Research Program, University of Texas at Austin, to increase distillation column throughput by over 6%, while also increasing energy efficiency by 10%. The research was conducted under a U. S. Department of Energy Cooperative Agreement awarded to George Dzyacky of 2ndpoint, LLC. The Flooding Predictor™ works by detecting the incipient flood point and controlling the column closer to its actual hydraulic limit than historical practices have allowed. Further, the technology uses existing column instrumentation, meaning no additional refining infrastructure is required. Refiners often push distillation columns to maximize throughput, improve separation, or simply to achieve day-to-day optimization. Attempting to achieve such operating objectives is a tricky undertaking that can result in flooding. Operators and advanced control strategies alike rely on the conventional use of delta-pressure instrumentation to approximate the column’s approach to flood. But column delta-pressure is more an inference of the column’s approach to flood than it is an actual measurement of it. As a consequence, delta pressure limits are established conservatively in order to operate in a regime where the column is never expected to flood. As a result, there is much “left on the table” when operating in such a regime, i.e. the capacity difference between controlling the column to an upper delta-pressure limit and controlling it to the actual hydraulic limit. The Flooding Predictor™, an innovative pattern recognition technology, controls columns at their actual hydraulic limit, which research shows leads to a throughput increase of over 6%. Controlling closer to the hydraulic limit also permits operation in a sweet spot of increased energy-efficiency. In this region of increased column loading, the Flooding Predictor is able to exploit the benefits of higher liquid

  14. Steel Planning

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    China releases a new plan for the iron and steel industry centered on industrial upgrades The new 12th Five-Year Plan (2011-15) for China’s iron and steel industry, recently released on the website of the Ministry of Industry and Information

  15. Experimental study of Q460c high strength steel welded H-section and box-section columns under cyclic loading%Q460C高强度结构钢焊接H形和箱形截面柱低周反复加载试验研究

    Institute of Scientific and Technical Information of China (English)

    李国强; 王彦博; 陈素文; 崔嵬; 孙飞飞

    2013-01-01

    In order to evaluate the seismic performance of high strength steel (HSS) columns, four H-section columns and four box-section columns were fabricated from flame-cut Q460C HSS to carry out quasi-static experiments. The constant axial load was maintained at 30% of the yield strength of cross-section during laterally cyclic loading. The hysteretic curves of the specimens were obtained and compared. According to the test, Q460C HSS welded columns with compact cross-sections show a good capacity of energy dissipation. The failure of the specimens with medium cross-sectional slenderness is induced by elasto-plastic local buckling. For specimens with very compact sections, plastic hinges with sufficient rotation capacity are developed at the fixed end of the specimens instead of local bucking. Finally, hysteretic models for welded H-section and box-section columns of Q460C HSS were proposed, which provide the foundation of further nonlinear static and time-history analyses of HSS structures under earthquake action.%为充分了解高强度结构钢构件的抗震性能,采用Q460C高强度结构钢焊接制作H形和箱形截面柱试件各4个,进行固定轴压比为0.3的低周反复加载试验.试验测得了Q460C高强度结构钢H形和箱形截面柱的荷载-位移滞回曲线和弯矩-曲率滞回曲线.试验结果表明:宽厚比接近GB 50011-2010《建筑抗震设计规范》中“一级抗震”限值的试件试验破坏模式为板件局部屈曲,而宽厚比远小于“一级抗震”限值的试件在柱底部可形成具有充分转动能力的塑性铰;宽厚比小于“二级抗震”限值的Q460C焊接H形截面柱和小于“一级抗震”的Q460C焊接箱形截面柱具有良好的耗能能力和抗震性能.在试验基础上提出了Q460C高强度结构钢焊接H形和箱形截面柱的弯矩-曲率滞回模型,为高强钢结构在地震作用下的弹塑性静力分析和时程分析提供参考.

  16. Experimental analysis of reinforced concrete columns strengthened with Self-Compacting concrete

    Directory of Open Access Journals (Sweden)

    M. Y. M. Omar

    Full Text Available This paper presents the results of reinforced concrete columns strengthened by addition of a self-compacting concrete overlay at the compressed and at the tensioned face of the member, with and without addition of longitudinal steel bars. Eight columns were submit- ted to loading with an initial eccentricity of 60 mm . These columns had 120 mm x 250 mm of rectangular cross section, 2000 mm in length and four longitudinal reinforcement steel bars with 10 mm in diameter. Reference columns P1 and P2 were tested to failure without any type of rehabilitation. Columns P3 to P8 were loaded to a predefined load (close to the initial yield point of tension reinforce- ment, then unloaded and strengthened for a subsequent test until failure. Results showed that the method of rehabilitation used was effective, increasing the loading capacity of the strengthened pieces by 2 to 5 times the ultimate load of the reference column.

  17. Seismic cyclic loading test of SRC columns confined with 5-spirals

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Presented herein is an experimental study on seismic resistance of rectangular steel reinforced concrete (SRC) columns confined with a new type of multi-spiral cage. The multi-spiral cage is a device of five interconnected spirals, named "5-spirals", with a large spiral at the center and four small ones at the corners. The innovation of applying the 5-spirals to SRC column is to take its superiority in concrete confinement and efficiency in automatic production for the precast construction industry. Four full-scale SRC columns were tested under horizontal cyclic loading. All of the tested columns were capable of sustaining a drift angle up to 6% radians. The hysteresis loops observed from the cyclic loading tests indicated that the spirally confined SRC columns demonstrated excellent performances in both strength and ductility. The test results suggested that with significant saving of the confinement steel, the newly innovated 5-spirals can be successfully applied to the precast rectangular SRC columns.

  18. Seismic behavior of semi-supported steel shear walls

    DEFF Research Database (Denmark)

    Jahanpour, A.; Jönsson, J.; Moharrami, H.

    2012-01-01

    During the recent past decade semi-supported steel shear walls (SSSW) have been introduced as an alternative to the traditional type of steel plate shear walls. In this system the shear wall does not connect directly to the main columns of the building frame; instead it is connected to a pair of ...

  19. Euler Teaches a Class in Structural Steel Design

    Science.gov (United States)

    Boyajian, David M.

    2009-01-01

    Even before steel was a topic of formal study for structural engineers, the brilliant eighteenth century Swiss mathematician and physicist, Leonhard Euler (1707-1783), investigated the theory governing the elastic behaviour of columns, the results of which are incorporated into the American Institute of Steel Construction's (AISC's) Bible: the…

  20. Optimum design of steel structures

    CERN Document Server

    Farkas, József

    2013-01-01

    This book helps designers and manufacturers to select and develop the most suitable and competitive steel structures, which are safe, fit for production and economic. An optimum design system is used to find the best characteristics of structural models, which guarantee the fulfilment of design and fabrication requirements and minimize the cost function. Realistic numerical models are used as main components of industrial steel structures. Chapter 1 containts some experiences with the optimum design of steel structures Chapter 2 treats some newer mathematical optimization methods. Chapter 3 gives formulae for fabrication times and costs. Chapters 4 deals with beams and columns. Summarizes the Eurocode rules for design. Chapter 5 deals with the design of tubular trusses. Chapter 6 gives the design of frame structures and fire-resistant design rules for a frame. In Chapters 7 some minimum cost design problems of stiffened and cellular plates and shells are worked out for cases of different stiffenings and loads...

  1. Experimental study on the seismic behavior of high strength concrete filled double-tube columns

    Science.gov (United States)

    Qian, Jiaru; Li, Ningbo; Ji, Xiaodong; Zhao, Zuozhou

    2014-03-01

    To study the seismic behavior of high strength concrete filled double-tube (CFDT) columns, each consisting of an external square steel tube and an internal circular steel tube, quasi-static tests on eight CFDT column specimens were conducted. The test variables included the width-to-thickness ratio ( β 1) and the area ratio ( β 2) of the square steel tube, the wall thickness of the circular steel tube, and the axial force (or the axial force ratio) applied to the CFDT columns. The test results indicate that for CFDT columns with a square steel tube with β 1 of 50.1 and 24.5, local buckling of the specimen was found at a drift ratio of 1/150 and 1/50, respectively. The lateral force-displacement hysteretic loops of all specimens were plump and stable. Reducing the width-to-thickness ratio of the square steel tube, increasing its area ratio, or increasing the wall thickness of the internal circular steel tube, led to an increased flexural strength and deformation capacity of the specimens. Increasing the design value of the axial force ratio from 0.8 to 1.0 may increase the flexural strength of the specimens, while it may also decrease the ultimate deformation capacity of the specimen with β 1 of 50.1.

  2. Eruption column physics

    Energy Technology Data Exchange (ETDEWEB)

    Valentine, G.A.

    1997-03-01

    In this paper the author focuses on the fluid dynamics of large-scale eruption columns. The dynamics of these columns are rooted in multiphase flow phenomena, so a major part of the paper sets up a foundation on that topic that allows one to quickly assess the inherent assumptions made in various theoretical and experimental approaches. The first part is centered on a set of complex differential equations that describe eruption columns, but the focus is on a general understanding of important physical processes rather than on the mathematics. The author discusses briefly the relative merits and weaknesses of different approaches, emphasizing that the largest advances in understanding are made by combining them. He then focuses on dynamics of steady eruption columns and then on transient phenomena. Finally he briefly reviews the effects of varying behavior of the ambient medium through which an eruption column moves. These final sections will emphasize concepts and a qualitative understanding of eruption dynamics. This paper relies on principles of continuum mechanics and transport processes but does not go into detail on the development of those principles. 36 refs., 36 figs., 3 tabs.

  3. Stability analysis of large diameter thin-walled tube beam-columns

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on a blind spot in the current design standard of steel structures,the large diameter thin-walled tube beam-columns are analyzed using nonlinear finite element method in this paper.The influence of several factors on stability capacity of the large diameter thinwalled tube beam-columns is taken into account.Thus,according to the correlative design standard of steel structures,and on the basis of the numerical analytical results by the finite element methods,the calculation formulas of the stability bearing capacity are presented for beam-column members of the large diameter thin-walled tubes.Three tests of thin-walled steel tube beam-columns were reported.Test results for deformations and ultimate strength are found to be in a good agreement with the corresponding values predicted by the calculation formulas,and the proposed methods can be used in design practice.

  4. Bond characteristics of steel fiber and deformed reinforcing steel bar embedded in steel fiber reinforced self-compacting concrete (SFRSCC)

    Science.gov (United States)

    Aslani, Farhad; Nejadi, Shami

    2012-09-01

    Steel fiber reinforced self-compacting concrete (SFRSCC) is a relatively new composite material which congregates the benefits of the self-compacting concrete (SCC) technology with the profits derived from the fiber addition to a brittle cementitious matrix. Steel fibers improve many of the properties of SCC elements including tensile strength, ductility, toughness, energy absorption capacity, fracture toughness and cracking. Although the available research regarding the influence of steel fibers on the properties of SFRSCC is limited, this paper investigates the bond characteristics between steel fiber and SCC firstly. Based on the available experimental results, the current analytical steel fiber pullout model (Dubey 1999) is modified by considering the different SCC properties and different fiber types (smooth, hooked) and inclination. In order to take into account the effect of fiber inclination in the pullout model, apparent shear strengths (τ (app)) and slip coefficient (β) are incorporated to express the variation of pullout peak load and the augmentation of peak slip as the inclined angle increases. These variables are expressed as functions of the inclined angle (ϕ). Furthurmore, steel-concrete composite floors, reinforced concrete floors supported by columns or walls and floors on an elastic foundations belong to the category of structural elements in which the conventional steel reinforcement can be partially replaced by the use of steel fibers. When discussing deformation capacity of structural elements or civil engineering structures manufactured using SFRSCC, one must be able to describe thoroughly both the behavior of the concrete matrix reinforced with steel fibers and the interaction between this composite matrix and discrete steel reinforcement of the conventional type. However, even though the knowledge on bond behavior is essential for evaluating the overall behavior of structural components containing reinforcement and steel fibers

  5. Fragility curves of concrete bridges retrofitted by column jacketing

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Northridge earthquake inflicted various levels of damage upon a large number of Caltrans' bridges not retrofitted by column jacketing. In this respect, this study represents results of fragility curve development for two (2) sample bridges typical in southern California, strengthened for seismic retrofit by means of steel jacketing of bridge columns. Monte Carlo simulation is performed to study nonlinear dynamic responses of the bridges before and after column retrofit. Fragility curves in this study are represented by Iognormal distribution functions with two parameters and developed as a function of PGA. The sixty (60) ground acceleration time histories for the Los Angeles area developed for the Federal Emergency Management Agcncy (FEMA) SAC (SEAOC-ATC-CUREe) steel project are used for the dynamic analysis of the bridges.The improvement in the fiagility with steel jacketing is quantified by comparing fragility curves of the bridge before and after column retrofit. In this first attempt to formulate the problem of fragility enhancement, the quantification is made by comparing the median values of the fragility curves before and after the retrofit. Under the hypothesis that this quantification also applies to empirical fragility curves developed on the basis of Northridge earthquake damage, the enhanced version of the empirical curves is developed for the ensuing analysis to determine the enhancement of transportation network performance due to the retrofit.

  6. Fragility curves of concrete bridges retrofitted by column jacketing

    Science.gov (United States)

    Shinozuka, Masanobu; Kim, Sang-Hoon; Kushiyama, Shigeru; Yi, Jin-Hak

    2002-12-01

    The Northridge earthquake inflicted various levels of damage upon a large number of Caltrans’ bridges not retrofitted by column jacketing. In this respect, this study represents results of fragility curve development for two (2) sample bridges typical in southern California, strengthened for seismic retrofit by means of steel jacketing of bridge columns. Monte Carlo simulation is performed to study nonlinear dynamic responses of the bridges before and after column retrofit. Fragility curves in this study are represented by lognormal distribution functions with two parameters and developed as a function of PGA. The sixty (60) ground acceleration time histories for the Los Angeles area developed for the Federal Emergency Management Agcncy (FEMA) SAC (SEAOC-ATC-CUREe) steel project are used for the dynamic analysis of the bridges. The improvement in the fragility with steel jacketing is quantified by comparing fragility curves of the bridge before and after column retrofit. In this first attempt to formulate the problem of fragility enhancement, the quantification is made by comparing the median values of the fragility curves before and after the retrofit. Under the hypothesis that this quantification also applies to empirical fragility curves developed on the basis of Northridge earthquake damage, the enhanced version of the empirical curves is developed for the ensuing analysis to determine the enhancement of transportation network performance due to the retrofit.

  7. 薄钢板部分外包组合截面柱-钢梁中节点T 形件焊接连接滞回性能研究%HYSTERETIC BEHAVIOR OF MEDIAN JOINT WITH WELDED SPLIT-TEE CONNECTION OF BUILT-UP THIN-WALLED CHANNEL SECTION PEC COLUMN-STEEL BEAM

    Institute of Scientific and Technical Information of China (English)

    陆森强; 方有珍

    2016-01-01

    To study the hysteretic behavior of partially encased composite ( PEC) columns fabricated with thin-walled channel built-up section and steel beams median joint with welded split-tee and pretension through-out high strength bolted connections, one specimen was designed and fabricated by 1∶1.6 scale which represented the median joint. The pseudo-static test for the specimen was conducted and ABAQUS software was simulated the test and to verify the rationality of the FE model.By comparison of the hysteretic behaviors, energy-dissipation capacity and failure mode, the results showed that through-out bolts exhibited partial self-centering function and effectively realized the force-transfer mechanism of concrete equivalent strut in the panel zone;the failure mode primary induced by plastic hinge formed in the steel beam section near the end of split-tee web because of strengthening and the rotation angles of the joint all surpassed 0.02 rad.%为研究采用预拉对穿螺栓的薄钢板部分外包组合截面( PEC)柱-钢梁中节点T形件焊接连接的滞回性能,按照1∶1.6缩尺设计制作了1个中节点试件,对其进行低周循环荷载试验,并采用有限元软件ABAQUS进行数值模拟验证,对比分析试件的滞回曲线、耗能能力和破坏模式。研究结果显示:预拉对穿螺栓具有部分自复位功效,且较好实现了混凝土斜压带传力机理;所有试件破坏模式均由于T形件对梁端加强而使梁截面塑性铰的出现位置向T形件腹板尾部附近梁截面转移,且所有试件达到破坏时,节点转角均超过了0.02 rad。

  8. Study on Seismic Performance of Cold-formed Thin-walled Square Steel Tube Beam-column Weld Joints%冷弯薄壁方钢管梁柱节点抗震性能试验及有限元研究

    Institute of Scientific and Technical Information of China (English)

    褚云朋; 姚勇; 徐斌; 王秀丽

    2013-01-01

    对12个冷弯薄壁型钢方钢管梁柱焊接节点进行了低周往复加载试验及非线性有限元数值模拟分析,有限元分析中考虑双重非线性、初始几何缺陷及焊材的本构模型等因素的影响.将循环荷载下数值计算结果与试验结果进行对比,讨论了试件滞回曲线、极限承载力、节点域应力分布等方面的内容.分析结果表明:(1)数值模拟与试验结果较为接近,极限荷载及极限位移差值在10%以内,所采用的数值分析模型和数值方法可进行冷弯薄壁型钢梁柱节点的参数化分析.(2)改进后的加腋节点极限承载力比常规节点高,极限状态时梁端位移较小;节点的滞回曲线饱满,耗能能力较强.(3)分散焊缝改进型节点破坏前经过循环次数较多,耗能能力较强.(4)轴压比对滞回性能及节点域应力分布有一定影响.%Low cyclic loading tests of 12 cold-formed thin-walled square steel tube beam-column weld joints are made and analyzed by nonlinear finite element numerical method,considering the impact of the dual nonlinearity,the initial geometric imperfections and constitutive model of welding consumables.The results of the two methods on hysteresis curve,ultimate bearing capacity,stress distribution of the specimens are compared.The result shows that numerical simulation can reflect the test results of the specimen well,and the numerical analysis models and numerical methods used for numerical simulation can analyze the cold-formed steel beam-column joints.Ultimate bearing capacity of the improved joint is larger than that of the conventional joint,and the displacement of the beam end is small when being the limit state.The improved joint has a full hysteresis curve,larger energy consumption ability,and the stiffness degradation is relatively slow.Axial compression ratio has a greater impact on the hysteretic behavior and stiffness,with the increase in axial compression ratio,both energy dissipation

  9. 装配式钢筋混凝土柱-钢梁框架节点抗震性能试验研究%Experimental study on seismic behavior of a new type of prefabricated RC column-steel beam frame connections

    Institute of Scientific and Technical Information of China (English)

    郭子雄; 朱奇云; 刘阳; 黄群贤

    2012-01-01

    A new type of RC columns-steel beams (RCS) connection was proposed, and four half scale RCS frame subassemblies were tested under low cyclic reversed loading to study the seismic behavior of prefabricated RCS subassemblies and mechanical behavior of the new type of connection. The test parameters were stiffened web thickness and openings. Based on the test results, the failure modes, load-displacement hysteretic response and deformation components were analyzed. The experimental results indicate that all specimens show good seismic behavior with spindle-shaped load versus story drift response. The formation of plastic hinges leads to good energy dissipation capacity of specimens. It is indicated that such bolted connection between steel beam and RC column has reliable connecting quality. Shear deformation of the joint region decreases with the increasing of stiffening web thickness. No adverse effects are observed due to the existence of holes at the stiffening web. Analytical results show that deformation component due to beam plastic hinging is dominant in the total story drift components of RCS subassemblies, while shear deformation component in the joint region is small.%通过4个1/2比例装配式钢筋混凝土柱-钢梁框架节点低周往复荷载作用下的试验研究,分析了节点区加劲腹板厚度及开孔的影响,研究该新型节点连接构造的受力性能及装配式钢筋混凝土柱-钢梁框架单元的抗震性能。基于试验结果对试件的破坏特征、滞回性能及变形组成进行分析。研究结果表明:装配式钢筋混凝土柱-钢梁框架节点滞回曲线呈纺锤形,梁端塑性铰区充分耗散能量,具有良好的抗震性能;装配式螺栓连接钢筋混凝土柱-钢梁混合节点具有良好的连接质量;加劲腹板厚度的增加一定程度上减小了节点的剪切变形,加劲腹板开孔对节点受力性能影响不大;梁弯曲变形引起的层间侧移在强柱弱梁型钢筋混凝

  10. Columns in Clay

    Science.gov (United States)

    Leenhouts, Robin

    2010-01-01

    This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today's…

  11. Performance of Hybrid Reinforced Concrete Beam Column Joint: A Critical Review

    Directory of Open Access Journals (Sweden)

    Md Rashedul Kabir

    2016-04-01

    Full Text Available Large residual strain in reinforced concrete structures after a seismic event is a major concern for structural safety and serviceability. Alternative reinforcement materials like fiber-reinforced polymer (FRP have been widely used to mitigate corrosion problems associated with steel. Low modulus of elasticity and brittle behavior compared to steel has made the use of FRP unsuitable in seismic resistant strictures. A combination of steel-FRP reinforcement configuration can address the problem of corrosion. Therefore, introducing a material that shows strong post elastic behavior without any decay due to corrosion is in demand. Shape memory alloy (SMA, a novel material, is highly corrosion resistive and shows super elastic property. Coupling SMA with FRP or steel in the plastic hinge region allows the structure to undergo large deformations, but regains its original shape upon unloading. In this study, the performance characteristics of four previously tested beam-column joints reinforced with different configurations (steel, SMA/steel, glass fiber reinforced polymer (GFRP and SMA/FRP are compared to assess their capacity to endure extreme loading. Experimental results are scrutinized to compare the behavior of these specimens in terms of load-story drift and energy dissipation capacity. SMA/FRP and SMA/Steel couples have been found to be an acceptable approach to reduce residual deformation in beam-column joints with adequate energy dissipation capacity. However, SMA/FRP is superior to SMA/Steel concerning to the corrosion issue in steel.

  12. Comparison Study of Axial Behavior of RPC-CFRP Short Columns

    Directory of Open Access Journals (Sweden)

    Taghreed Khaleefa Mohammed Ali

    2015-05-01

    Full Text Available In this paper, the axial behaviors of reactive powder     concrete (RPC short  columns confined with carbon fiber reinforced polymer (CFRP were   investigated. All the specimens have square cross section of 100 mm × 100   mm and length of 400 mm with aspect ratio 4. The experimental work consists   of three groups. The first group consists of six specimens of RPC with 2%  micro steel fiber, without ordinary reinforcing steel and confining by zero, one and two layer of CFRP respectively. The second group consists of six    specimens of RPC with 2% micro steel fiber and minimum ordinary reinforcing  steel and confining by zero, one and two layers of CFRP respectively. The third  group consists of four specimens of RPC without micro steel fiber and ordinary  reinforcing steel and confining by one and two layers of CFRP respectively.  Experimental data for strength, longitudinal and lateral displacement and  failure mode were obtained for each test. The toughness (area under the curve  for each test was obtained by using numerical integration. The RPC columns confined with CFRP showed stiffer behavior compared with RPC columns without CFRP. The ultimate load of the RPC columns with 2% micro steel  fiber + two layers of CFRP + minimum ordinary reinforcement were more than that of the RPC columns with 2% micro steel fiber + minimum ordinary   reinforcement and without CFRP by about 1.333.

  13. Behavior of Columns During Earthquakes

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The behavior of columns during earthquakes is very important since column failures may lead to additional structural failures and result in total building collapses....

  14. Determination of Two Columns Performance

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    When protein is analyzed by high performance liquid chromatography (HPLC), the selection of column is one of the most important factors. There are four quality control parameters for the column, which are theoretical plates n, capacity facto

  15. NMFS Water Column Sonar Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water column sonar data are an important component of fishery independent surveys, habitat studies and other research. NMFS water column sonar data are archived here.

  16. Application of Compactness Detection to Complicated Concrete-Filled Steel Tube by Ultrasonic Method

    Institute of Scientific and Technical Information of China (English)

    杨建江; 王飞; 陆苏亮; 王川

    2014-01-01

    An example of using ultrasonic method to detect the compactness of complicated concrete-filled steel tube in certain high-rise building was discussed in this study. Because of the particularity of the complicated concrete-filled steel tubular column, the plane detection method and embedded sounding pipe method were adopted in the process of effectively detecting the column. According to the results of the plane detection method and embedded sounding pipe method, the cementing status of steel tube and concrete can be concluded, which cannot be judged by the hammering method in the rectangular steel tube-reinforced concrete.

  17. Evaluation of column hardware on liquid chromatography-mass spectrometry of phosphorylated compounds.

    Science.gov (United States)

    Sakamaki, Hiroshi; Uchida, Takeharu; Lim, Lee Wah; Takeuchi, Toyohide

    2015-02-13

    The influences of column hardware, such as chromatographic tubes and frits, on liquid chromatography-mass spectrometry (LC-MS) analysis of phosphorylated compounds were evaluated. The signal to noise ratio (S/N) and the intensity of flavin adenine dinucleotide (FAD) using a glass lined tube and polyethylene frit (GL-PE) column was approximately 170 and 90 times higher, respectively, than those using conventional stainless steel tube and stainless steel frit (S-S) column. In addition, the retention time of FAD using GL-PE column was the shortest compared to other columns. Interaction between phosphorylated compounds and metal ions in the flow path in the S-S column was stronger than that between them and the GL-PE column. Thus, the metal ions in the flow path in GL-PE column were low. Since the specific surface area of a pair of frits was 70 times larger than that of a chromatographic tube (150 mm×2.1 mm), the frits were found to have more effective improvement of the S/N as well as the intensity than the chromatographic tubes, when phosphorylated compounds were analyzed by LC-MS. When the evaluated phosphorylated compounds were analyzed by LC-MS(/MS) using a GL-PE column, the intensity and S/N were increased.

  18. Experimental Evaluation of the Failure of a Seismic Design Category - B Precast Concrete Beam-Column Connection System

    Science.gov (United States)

    2014-12-01

    specimen to examine the specimen, but not inside the reaction frame . 8. The load will removed from the stub column, and the specimen will be braced to...experiment to test a precast concrete beam-column system to failure. This experiment was designed to evaluate the performance of precast frame ...54  Figure 81. Strains in top lateral steel brace beam

  19. High Nitrogen Stainless Steel

    Science.gov (United States)

    2011-07-19

    Kiev, 1993. 7. High Nitrogen Steels, edited by M. Kikuchi and Y. Mishima , Vol. 36, No. 7, Iron and Steel Institute of Japan Inernational, Tokyo...the Corrosion of Iron and Steels,” High Nitrogen Steels, edited by M. Kikuchi and Y. Mishima , Vol. 36, No. 7, Iron and Steel Institute of Japan

  20. New Numerical Study for Strengthened short columns with different jackets techniques

    Directory of Open Access Journals (Sweden)

    usama mostafa mahran

    2013-04-01

    Full Text Available Today, the use of fibreshotcrete for strengthening the concrete structures in large scale is increasing due to its advantage. The properties and the factors effect on it, has been discussed. This work presents a theoretical investigation concerning the efficiency of different strengthening systems for the reinforced concrete columns. In this work, the experimental results for six columns (20x20x100 had the same cross section of dimensions and main longitudinal reinforcement distribution and cross sections for all columns. These Columns had four deformed longitudinal steel with 10 mm diameter were tested under compression loading will study, C0 column without strengthening, columns C6, and C7 were strengthened with Strips of CFRP were 2 mm and 4 mm thickness respectively, these were placed onto the column surface in the lateral direction with epoxy resin. Others three columns had four deformed longitudinal steel bars 10 mm diameter. Column C1 strengthened with fibreshotcrete jacket layer 3cm thickness, C2 similar C1 except additional stirrups in lateral direction 8 mm diameters each 200 mm with reinforcement and C5 column 26*26 cm cross section with no strengthening. Columns were tested under compression loading and The deformations were measured by linear variable differential transducers LVDT’s, two transducers in both sides to measure the longitudinal deformations ( LO and three in the lateral direction to measure the lateral deformations: the first (EQ1 was near the end of the column, the second (EQ2 was in the middle and the third (EQ3 was in the middle between the fist and the second had the same cross section of dimensions and main longitudinal reinforcement distribution and cross sections. I produced a new formula in the three dimensional for numerical modeling to compare between strengthening columns.

  1. Column: Every Last Byte

    Directory of Open Access Journals (Sweden)

    Simson Garfinkel

    2011-06-01

    Full Text Available Inheritance powder is the name that was given to poisons, especially arsenic, that were commonly used in the 17th and early 18th centuries to hasten the death of the elderly. For most of the 17th century, arsenic was deadly but undetectable, making it nearly impossible to prove that someone had been poisoned. The first arsenic test produced a gas—hardly something that a scientist could show to a judge. Faced with a growing epidemic of poisonings, doctors and chemists spent decades searching for something better.(see PDF for full column

  2. Near shore floating oscillating wave column

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    Three different types of floating buoys, using oscillating wave columns, have been considered for generating electric power in an Atlantic environment. The study considered the situation close to the shore, but in the ultimate it was hoped to deploy units offshore. Although other designs would have greater power capture efficiency, the Spar Buoy was studied in greatest depth as it was expected to have the edge in terms of building cost and operating economics. A risk assessment was carried out for both concrete and steel buoys. The report covers (1) history of the project development; (2) project definition; (3) power generation and sensitivities and (4) lessons learned. The study was sponsored by Great Britain's DTI.

  3. Numerical Simulation of Seismic Behavior of Beam-Column Connection for Self-centering Steel Frame with Bottom Flange Friction Devices%下翼缘摩擦式自定心钢框架梁柱节点抗震性能的数值模拟

    Institute of Scientific and Technical Information of China (English)

    宋良龙; 郭彤

    2011-01-01

    介绍了一种新型的钢框架梁柱节点形式,其中预应力钢绞线提供了结构在地震作用下的复位功能(自定心),设置在梁端下翼缘的摩擦件则为结构提供了耗能能力;介绍了下翼缘摩擦式自定心钢框架梁柱节点的构造和工作原理,以节点的低周反复加载试验结果为依据,利用面向对象的开放式计算程序OpenSees建立了节点的数值模型,并侧重于模拟节点在地震作用下的张开/闭合、自定心、摩擦耗能以及螺栓受剪等特性.由计算结果与试验结果对比可知,所建立的数值模型对节点的抗震性能具有良好的模拟效果.%This paper presents a novel beam-column connection for steel moment resisting frames, in which the post-tensioning forces provide the ability of self-centering under earthquake, and the bottom flange friction device (BFFD) , located at beam ends, provides the energy dissipation. The operation principle and constitution of the BFFD connection are presented. Based on the low cyclic test results of the BFFD connection , a numerical model is established by using the Open System for Earthquake Engineering Simulation (OpenSees) to model the hysteretic behavior of the BFFD connection, including the gap opening/closing, self-centering, friction energy dissipation and the bolt bearing, etc. Comparison between the numerical simulation and the experiment results shows that the proposed numerical model can accurately simulate the hysteretic behavior of the BFFD connection.

  4. Study on Seismic Behavior of Square Steel Tube Concrete Column Beam Joints Shaped Top-seat with L-plat%L 形方钢管混凝土组合柱钢梁顶底角连接节点的抗震性能研究

    Institute of Scientific and Technical Information of China (English)

    蒲瑜

    2016-01-01

    提出了一种 L 形方钢管混凝土组合柱钢梁顶底角连接新型组合节点,为了论证新型节点的抗震性能,利用模拟地震加载试验对四个指标均相同的试件进行了实验。试验结果表明,4个试件在位移-30 mm 前,荷载随位移的增加而减小,在位移大于0之后,荷载随位移的增加而增加,表明试件的正向塑性能力比反向塑性能力要好。随着累积滞回耗能的增加,试件能量耗散也随之增大,其中能量耗散在累积滞回耗能为4Δy之前,增加的趋势较为缓慢,而在累积滞回耗能大于4Δy后,能量耗散增加的趋势较为迅速。试件刚度退化中 L1最慢,其抗震性能的较其他3个要好。%A new type of seismic behavior of square steel tube concrete column beam joints shaped top-seat with L-plat is investigated,and four specimens model connections were tested under simulated seismic loading.Experimental results show that the four specimens in front of the displacement -30 mm, load decreases with the increase in displacement,displacement is greater than 0,load increases with the increase of displacement,indicating that the positive plastic ability than the reverse plastic ability is bet-ter.With the increase of cumulative hysteretic energy,energy dissipation increases,which energy dissipa-tion in cumulative hysteretic energy for 4Δy before the increase trend is relatively slow,and accumulated hysteretic energy dissipation is greater than 4Δy,and trend of the energy dissipation increases more rapid-ly.L1 is the slowest,and the seismic performance of the specimen is better than that of the other three.Under the action of repeated load,the failure of the joint occurs in the beam end,the node strength reserve is higher,the shape of the hysteresis curve is full,the new column node has high shear capacity and good seismic performance.With the increase of the axial compression ratio,the displacement ductility coefficient of the

  5. 梁柱弱轴连接翼缘削弱型节点的滞回性能研究%Analysis on the Hysteretic Behavior of Reduced Section Beam-to-Column Connections in Minor-Axis Direction of Steel Frames

    Institute of Scientific and Technical Information of China (English)

    郁有升; 孙婷; 王燕

    2013-01-01

    To study the hysteretic behavior and the skeleton curve of reduced beam section (RBS) beam-to-column connections in minor-axis direction of steel frames, a series of finite element models were established according to frequently-used major-axis connection parameters. The effects of these factors such as the distance of the weakening position of flange beam to the centerline of the columns, reduced length and reduced depth on the hysteretic behavior of the specimens were analyzed by ANSYS. The results indicated that the reduced parameters had little impact on the skeleton curves before the connections yielded,however,the effects on the yield capacity and ultimate capacity could not be neglected after the connections yielded. The reduced depth had the most significant influence on the skeleton curves,the reduced distance had the second most influence on the skeleton curves, while the reduced length had the least influence on the skeleton curves. The results also indicated that the reduced parameters of major-axis connections may not be directly suitable for minor-axis connections. Moreover,the reasonable ranges of each parameter of reduced beam section connections were given.%针对钢框架梁柱弱轴连接翼缘削弱型节点的滞回性能和骨架曲线,参照梁柱强轴连接的削弱参数,设计了梁柱弱轴连接翼缘削弱型节点系列试件,应用有限元软件ANSYS研究了削弱区中心至柱中心线距离、削弱宽度以及削弱深度对节点滞回性能的影响.研究结果表明:在往复荷载作用下,节点屈服以前,模型的削弱参数对节点的骨架曲线影响不大;节点屈服以后,削弱参数对节点的屈服荷载和极限承载力的影响比较明显,其中削弱部位的深度对骨架曲线的影响最大,削弱区中心至柱中心线距离对骨架曲线的影响次之,削弱部位长度对骨架曲线的影响最小.研究还表明强轴连接的削弱参数不能完全适用于弱轴连接节点,并给出

  6. Advanced analysis and design for fire safety of steel structures

    CERN Document Server

    Li, Guoqiang

    2013-01-01

    Advanced Analysis and Design for Fire Safety of Steel Structures systematically presents the latest findings on behaviours of steel structural components in a fire, such as the catenary actions of restrained steel beams, the design methods for restrained steel columns, and the membrane actions of concrete floor slabs with steel decks. Using a systematic description of structural fire safety engineering principles, the authors illustrate the important difference between behaviours of an isolated structural element and the restrained component in a complete structure under fire conditions. The book will be an essential resource for structural engineers who wish to improve their understanding of steel buildings exposed to fires. It is also an ideal textbook for introductory courses in fire safety for master’s degree programs in structural engineering, and is excellent reading material for final-year undergraduate students in civil engineering and fire safety engineering. Furthermore, it successfully bridges th...

  7. Robust naphthyl methacrylate monolithic column for high performance liquid chromatography of a wide range of solutes.

    Science.gov (United States)

    Jonnada, Murthy; El Rassi, Ziad

    2015-08-28

    An organic monolithic column based on the co-polymerization of 2-naphthyl methacrylate (NAPM) as the functional monomer and trimethylolpropane trimethacrylate (TRIM) as the crosslinker was introduced for high performance reversed-phase liquid chromatography (RPC). The co-polymerization was performed in situ in a stainless steel column of 4.6mm i.d. in the presence of a ternary porogen consisting of 1-dodecanol and cyclohexanol. This monolithic column (referred to as naphthyl methacrylate monolithic column or NMM column) showed high mechanical stability at relatively high mobile phase flow velocity indicating that the column has excellent hydrodynamic characteristics. To characterize the NMM column, different probe molecules including alkyl benzenes, and aniline, benzene, toluene and phenol derivatives were chromatographed on the column and the results in terms of k, selectivity and plate counts were compared to those obtained on an octadecyl silica (ODS) column in order to assess the presence of π-π and hydrophobic interactions on the NMM column under otherwise the same elution conditions. The NMM column offered additional π-π interactions with aromatic molecules in addition to hydrophobic interactions under RPC elution conditions. Run-to-run and column-to-column reproducibility of solute k values were evaluated, and percent relative standard deviation of column using shallow (30min at 1.0mL/min), steep (10min at 1.0mL/min) and ultra steep (1min at 3.0mL/min) linear gradient elution at increasing ACN concentration in the mobile phase using a 10cm×4.6mm i.d. column in case of shallow and steep linear gradients and a 3cm×4.6mm i.d. column for ultra steep linear gradient.

  8. Seismic Performance of Steel Structures at Lingzhao Veranda in the Forbidden City%故宫灵沼轩钢结构抗震性能分析

    Institute of Scientific and Technical Information of China (English)

    周乾; 闫维明; 纪金豹

    2015-01-01

    基于钢结点的半刚性特征及退化现状,建立结构有限元模型。通过模态分析,研究结构基频和主振型;通过谱分析,研究Ⅷ度常遇地震作用下钢结构的内力及变形分布特征;通过时程分析,研究Ⅷ度罕遇地震作用下钢结构的抗倒塌能力。结果表明:灵沼轩钢结构基频为5.31 Hz,主振型以钢框架顶部的八角亭水平向弯曲为主。Ⅷ度常遇地震作用下,由于钢框架2层顶部结点刚度退化严重,其变形和内力普遍较大,但满足容许值要求。Ⅷ度罕遇地震作用下,钢结构薄弱层的变形峰值在容许范围内,结构不会产生倒塌。%Lingzhao Veranda (also called Crystal Palace)is located in the eastern part of the Pal-ace Museum (the Forbidden City),which was planned for the amusement of the royal family in 20 th century.However,construction of the building lasted only three years,and the building has lain idle until the present.The building is composed of a center bearing frame and four surround-ing white marble verandas.The frame is composed of I-section steel beams and a ring of iron col-umns.In addition,on top of the bearing frame and verandas,there are five iron booths.Because the building has been idle for nearly 100 years,structural problems have appeared on the frame due to a number of factors,such as shortage of bolts,slack in joint connections,and cracks in the iron columns.The National Center for Quality Supervision and Testing of Building Engineering has conducted on-site inspections of the steel structure,and concluded that the beams and columns are structurally sound.However,the joints need to be strengthened.As a historic building,the Ling-zhao Veranda is worth protection for its artistic,historical,cultural,and architectural values.To effectively protect this historic building,it is necessary to assess its current structural safety.Such an assessment may provide a direction for future maintenance and restoration of the building

  9. Studies on the behavior of Reinforced Concrete Short Column subjected to fire

    Directory of Open Access Journals (Sweden)

    Aneesha Balaji

    2016-03-01

    Full Text Available The paper investigates the axial capacity of reinforced columns exposed to fire. The simplified method namely 500 °C isotherm method explained in Eurocode 2 is used to assess the capacity of the column. Finite element software ANSYS is used to perform the thermal analysis. A set of numerical studies were carried out to quantify the effect of various parameters on short columns subjected to fire. The study is performed on columns of different cross-sections to investigate the effect of eight parameters, namely the thermal boundary conditions, grades of concrete, grades of steel, types of aggregate, distribution of reinforcement on column faces, concrete cover, load eccentricity and support conditions. The fire ratings based on various failure criteria are determined, and minimum rating is accepted as design fire rating. A simplified interaction curve to predict the failure of columns under fire subjected to axial load and uniaxial moment for square cross-sections was also developed.

  10. Why Hexagonal Basalt Columns?

    Science.gov (United States)

    Hofmann, Martin; Anderssohn, Robert; Bahr, Hans-Achim; Weiß, Hans-Jürgen; Nellesen, Jens

    2015-10-09

    Basalt columns with their preferably hexagonal cross sections are a fascinating example of pattern formation by crack propagation. Junctions of three propagating crack faces rearrange such that the initial right angles between them tend to approach 120°, which enables the cracks to form a pattern of regular hexagons. To promote understanding of the path on which the ideal configuration can be reached, two periodically repeatable models are presented here involving linear elastic fracture mechanics and applying the principle of maximum energy release rate. They describe the evolution of the crack pattern as a transition from rectangular start configuration to the hexagonal pattern. This is done analytically and by means of three-dimensional finite element simulation. The latter technique reproduces the curved crack path involved in this transition.

  11. Column: File Cabinet Forensics

    Directory of Open Access Journals (Sweden)

    Simson Garfinkel

    2011-12-01

    Full Text Available Researchers can spend their time reverse engineering, performing reverse analysis, or making substantive contributions to digital forensics science. Although work in all of these areas is important, it is the scientific breakthroughs that are the most critical for addressing the challenges that we face.Reverse Engineering is the traditional bread-and-butter of digital forensics research. Companies like Microsoft and Apple deliver computational artifacts (operating systems, applications and phones to the commercial market. These artifacts are bought and used by billions. Some have evil intent, and (if society is lucky, the computers end up in the hands of law enforcement. Unfortunately the original vendors rarely provide digital forensics tools that make their systems amenable to analysis by law enforcement. Hence the need for reverse engineering.(see PDF for full column

  12. European Analytical Column

    DEFF Research Database (Denmark)

    Karlberg, B.; Grasserbauer, M.; Andersen, Jens Enevold Thaulov

    2009-01-01

    The European Analytical Column has once more invited a guest columnist to give his views on various matters related to analytical chemistry in Europe. This year, we have invited Professor Manfred Grasserbauer of the Vienna University of Technology to present some of the current challenges...... for European analytical chemistry. During the period 2002–07, Professor Grasserbauer was Director of the Institute for Environment and Sustainability, Joint Research Centre of the European Commission (EC), Ispra, Italy. There is no doubt that many challenges exist at the present time for all of us representing...... a major branch of chemistry, namely analytical chemistry. The global financial crisis is affecting all branches of chemistry, but analytical chemistry, in particular, since our discipline by tradition has many close links to industry. We have already noticed decreased industrial commitment with respect...

  13. SPIRAL CONTACTOR FOR SOLVENT EXTRACTION COLUMN

    Science.gov (United States)

    Cooley, C.R.

    1961-06-13

    The patented extraction apparatus includes a column, perforated plates extending across the column, liquid pulse means connected to the column, and an imperforate spiral ribbon along the length of the column.

  14. Compact electron beam focusing column

    Energy Technology Data Exchange (ETDEWEB)

    Persaud, Arun; Leung, Ka-Ngo; Reijonen, Jani

    2001-07-13

    A novel design for an electron beam focusing column has been developed at LBNL. The design is based on a low-energy spread multicusp plasma source which is used as a cathode for electron beam production. The focusing column is 10 mm in length. The electron beam is focused by means of electrostatic fields. The column is designed for a maximum voltage of 50 kV. Simulations of the electron trajectories have been performed by using the 2-D simulation code IGUN and EGUN. The electron temperature has also been incorporated into the simulations. The electron beam simulations, column design and fabrication will be discussed in this presentation.

  15. Combination of Slag, Limestone and Sedimentary Apatite in Columns for Phosphorus Removal from Sludge Fish Farm Effluents

    Directory of Open Access Journals (Sweden)

    Florent Chazarenc

    2010-08-01

    Full Text Available Laboratory scale studies have repeatedly reported high P-retention in slag, a by-product of the steel manufacturing industry. Thus, it has emerged as a potential material to increase P-removal from constructed wetlands (CWs. However, several limitations were highlighted by field experiments, including the high pH of treated water and clogging. We hypothesized that the addition of sedimentary rocks to slag would preserve P-removal properties while reducing the pH of treated water. Four 2.5 L-columns were filled with 100% apatite (column A; a 50% weight each mixture of limestone with apatite (column B; 10% steel slag located at the inlet, plus 45% limestone mixed with 45% apatite (column C; and a mixture of steel slag (10%, limestone (45% apatite (45% (column D. A synthetic effluent (26 mg P/L and a reconstituted sludge fish farm effluent containing 97 mg/L total suspended solids (TSS, 220 mg/L chemical oxygen demand (COD and 23.5 mg P/L phosphorus (P were applied sequentially during 373 and 176 days, under saturated flow conditions and 12–24 hours hydraulic residence time (HRT, respectively. Treatment performance, P-removal, pH and calcium (Ca2+ were monitored. Results indicated that columns that contained 10% weight steel slag resulted in a higher P retention capacity than the columns without steel slag. The highest P removal was achieved in column C, containing a layer of slag in the inlet zone, 45% apatite and 45% limestone. Feeding the columns with a reconstituted fish farm effluent led to biofilm development, but this had little effect on the P-removal. A combination of slag and sedimentary rocks represents a promising filtration material that could be useful downstream of CWs to further increase P-removal.

  16. Cost and Ductility Effectiveness of Concrete Columns Strengthened with CFRP and SFRP Sheets

    Directory of Open Access Journals (Sweden)

    Khaled Abdelrahman

    2014-05-01

    Full Text Available Recently, steel fibre reinforced polymers (SFRP sheets have been introduced for the repair and rehabilitation of concrete structures. Few researchers studied the behaviour of the concrete columns wrapped with SFRP sheets; however, several critical parameters such as the cost and ductility effectiveness of the SFRP wrapped concrete columns have been lightly addressed. Thus, the main objective of this paper is to study the cost and ductility effectiveness of SFRP wrapped concrete columns and compare the results with the conventionally used carbon FRP (CFRP wrapped concrete columns. In addition, an analytical procedure to predict the cost effectiveness of SFRP wrapped concrete columns is also suggested, from which, a parametric study was conducted. The parametric study investigated the effect of the concrete strength, the number of SFRP layers, and the size and slenderness effects on the cost effectiveness of the concrete columns wrapped with SFRP sheets. The results from the cost and ductility effectiveness study indicated that the SFRP wrapped concrete columns showed enhanced performance over the CFRP wrapped concrete columns. The suggested analytical procedure proved to be a reliable and accurate method to predict the cost effectiveness parameter of SFRP wrapped concrete columns. The parametric study showed the significant impact of the investigated parameters on the cost effectiveness of concrete columns wrapped with SFRP sheets.

  17. Market challenges for steel

    Energy Technology Data Exchange (ETDEWEB)

    Lauprecht, W.E.; Bulla, W.

    1981-11-01

    Country-wise division of generation of high-alloyed steels, stainless steel and alloyed steel in Western Europe/the Western World. Review of expanding markets for alloyed steels on sectors like-oil field pipes, offshore structure gas- and oil transport in pipelines, coal conversion, nuclear energy, condenser tubes, solar energy, car industry, environmental protection and chemistry.

  18. Practical design of stepped columns

    NARCIS (Netherlands)

    Girao Coelho, A.M.; Simao, P.D.; Bijlaard, F.S.K.

    2012-01-01

    This paper deals with buckling aspects of the design of stepped columns in heavy mill buildings. In these structures, columns have to carry significant axial loads that usually act eccentrically and strength reducing bending moments due to lateral loads. A simple physical model for buckling behaviou

  19. An Undergraduate Column Chromatography Experiment.

    Science.gov (United States)

    Danot, M.; And Others

    1984-01-01

    Background information, list of materials needed, and procedures used are provided for an experiment designed to introduce undergraduate students to the theoretical and technical aspects of column chromatography. The experiment can also be shortened to serve as a demonstration of the column chromatography technique. (JN)

  20. Dynamic analysis of composite columns in Inelastic state

    Directory of Open Access Journals (Sweden)

    Mohsen Rezaie Hajidehi

    2013-06-01

    Full Text Available The main objective of this study is analyzing Seismic behavior of composite columns in frame in inelastic state under dynamic load. Therefore, three type of composite column have been used in this paper. IPB Steel section embedded in concrete (type 1, Concrete-filled thin-walled steel sections (type 2, half concreted IPB sections (type 3 which are designed for 3 and 8 floor frame tenement in plastic way. Three earthquake accelerogram have been used for analyzing model seismic behavior and model analysis has been done in non-linear dynamic analysis with Seismostruct application. The results demonstrated that frame designed by composite columns type 1 and 3 in the flexural behavior, have similar construction behavior in the way that plasticity, softness and good function to dispose lateral forces are the same.  Although Type 2 composite model have large sections, have poor performance in tolerating flexural moment. This event refers to poor role of concrete in tension. On the other hand, the amount of concrete is important in Withstand compressive forces and in constructions with high compressive forces, type 1 and 2 have better performance.

  1. Plasma nitriding of steels

    CERN Document Server

    Aghajani, Hossein

    2017-01-01

    This book focuses on the effect of plasma nitriding on the properties of steels. Parameters of different grades of steels are considered, such as structural and constructional steels, stainless steels and tools steels. The reader will find within the text an introduction to nitriding treatment, the basis of plasma and its roll in nitriding. The authors also address the advantages and disadvantages of plasma nitriding in comparison with other nitriding methods. .

  2. Mush Column Magma Chambers

    Science.gov (United States)

    Marsh, B. D.

    2002-12-01

    Magma chambers are a necessary concept in understanding the chemical and physical evolution of magma. The concept may well be similar to a transfer function in circuit or time series analysis. It does what needs to be done to transform source magma into eruptible magma. In gravity and geodetic interpretations the causative body is (usually of necessity) geometrically simple and of limited vertical extent; it is clearly difficult to `see' through the uppermost manifestation of the concentrated magma. The presence of plutons in the upper crust has reinforced the view that magma chambers are large pots of magma, but as in the physical representation of a transfer function, actual magma chambers are clearly distinct from virtual magma chambers. Two key features to understanding magmatic systems are that they are vertically integrated over large distances (e.g., 30-100 km), and that all local magmatic processes are controlled by solidification fronts. Heat transfer considerations show that any viable volcanic system must be supported by a vertically extensive plumbing system. Field and geophysical studies point to a common theme of an interconnected stack of sill-like structures extending to great depth. This is a magmatic Mush Column. The large-scale (10s of km) structure resembles the vertical structure inferred at large volcanic centers like Hawaii (e.g., Ryan et al.), and the fine scale (10s to 100s of m) structure is exemplified by ophiolites and deeply eroded sill complexes like the Ferrar dolerites of the McMurdo Dry Valleys, Antarctica. The local length scales of the sill reservoirs and interconnecting conduits produce a rich spectrum of crystallization environments with distinct solidification time scales. Extensive horizontal and vertical mushy walls provide conditions conducive to specific processes of differentiation from solidification front instability to sidewall porous flow and wall rock slumping. The size, strength, and time series of eruptive behavior

  3. 40 CFR 799.6786 - TSCA water solubility: Generator column method.

    Science.gov (United States)

    2010-07-01

    ... stages of certain life forms). Even organisms which are adapted to life in a gaseous environment require... means of stainless steel fittings with teflon ferrules. The column is enclosed in a water jacket for... Water Jacket and Overall Arrangement of the Apparatus Used in the GC Method ER15DE00.056 (B) Constant...

  4. Random fields of initial out of straightness leading to column buckling

    DEFF Research Database (Denmark)

    Kala, Zdeněk; Valeš, Jan; Jönsson, Jeppe

    2017-01-01

    The elastic load-carrying capacity and buckling trajectory of steel columns under compression with open and hollow cross-sections, whose axis is curved by spatial random fields, are studied in the article. As a result of the spatial curvature of the axis the cross-sections are subjected to compre...

  5. Experimental research on seismic behavior of beam-column connection with welded haunch in cold-formed thin-walled square steel tube structure%冷弯薄壁方钢管梁柱加腋节点抗震性能研究

    Institute of Scientific and Technical Information of China (English)

    张春涛; 李正良; 王汝恒; 贾彬

    2012-01-01

    汶川地震后在灾区重建过程中大量使用冷弯薄壁方钢管,但其梁柱节点的连接方式和力学性能等尚需进一步研究.基于结构实际受力情况设计了一种三维双节点试验模型,对不同轴压比下冷弯薄壁方钢管梁柱加腋节点和普通节点的8个试件进行了足尺试验,通过对比分析研究了低周往复荷载作用下加腋节点的破坏模式、滞回曲线及评价节点抗震性能的主要参数(承载力、延性、刚度退化和能量耗散系数等).同时,利用ANSYS对各节点进行了有限元数值计算,并与试验结果进行对比分析进一步对加腋节点进行了研究.结果表明:试验与有限元数值计算结果吻合良好,验证了理论分析的正确性;加劲腋板提高了节点的初始刚度和承载力,钢管梁的弹塑性性能得到了充分发挥,不同轴压比下均出现了塑性铰,导致加腋节点各试件的最终破坏均是由钢管梁塑性变形过大出现局部屈曲引起;加劲腋板提高了节点的延性系数及往复变形次数,延长了变形时间,增大了节点的粘滞阻尼和耗能性性能,改善了节点的抗震性能;随轴压比增加,加腋节点塑性变形减小,脆性破坏特征增加,各耗能系数均相应降低.%The cold-formed thin-walled square steel tube has been widely applied in post-seismic reconstruction area after the Wenchuan earthquake. As there are no detail design instructions about this kind of structure, a further study is demanded on the connection mode and mechanical properties of the beam-column connection in the tube structure. A tridimensional double connection points model was proposed according to the actual building structure. By using cycling loading test, two types of full-scale beam-column connections ( 8 specimens) under different axial compression ratios were studied, among which four connections are welded with haunch slabs, and the others are not. According to the comparison of the results

  6. Prediction of the Service Life of a Reinforced Concrete Column under Chloride Environment

    Directory of Open Access Journals (Sweden)

    Mohammad K. Alkam

    2015-01-01

    Full Text Available In the present investigation, service life of a reinforced concrete column exposed to chloride environment has been predicted. This study has been based on numerical simulation of chloride ion diffusion in a concrete column during its anticipated life span. The simulation process has included the concrete cover replacement whenever chloride ion concentration has reached the critical threshold value at the reinforcement surface. Repair scheduling of the concrete column under consideration has been discussed. Effects of the concrete cover thickness and the water cement ratio on the service life of the concrete column at hand have been presented. A new approach for arranging locations of reinforcement steel bars has been introduced. This approach is intended to prolong the service life of the concrete column under consideration against chloride induced corrosion.

  7. A Simple Design to Realize Micro-column Separation by Conventional Analytical HPLC

    Institute of Scientific and Technical Information of China (English)

    GONG,Wenjun; ZHANG,Junxia; ZHANG,Yuping; ZHANG,Yijun; TIAN,Mengkui; WU,Dafu

    2009-01-01

    The conventional analytical HPLC was successfully developed for micro-column separation by using a simple eluate splitting system,self-preparation of packing column and on-capillary column detector in our laboratory.Porous inlet frit in fused silica capillary was rapidly prepared by sintering stainless steel powders under 500 meshes for about 20 s.The use of such frits or metal meshes in capillary to retain C18 particles of chromatographic packing was demonstrated to be stable and specially robust with continuous packing and long chromatographic runs.Furthermore,the chromatographic behavior was detailedly evaluated by changing the flow rate and the percentage of mobile phase using the prepared capillary column.Under the optimal experimental conditions,baseline separation of the model analytes including thiourea,benzene,toluene,ethylbenzene was obtained with a high column efficiency near 70000N (plates/m) by the developed capillary-HPLC.

  8. Numerical Simulation of Response of SRC Columns Subjected to Blast Loading

    Institute of Scientific and Technical Information of China (English)

    SUN Jianyun; LI Guoqiang; LU Yong

    2006-01-01

    The dynamic characteristics and failure modes of steel reinforced concrete (SRC) columns subjected to blast loading are complicated because of the transient stress wave in the SRC columns and the interaction between steel and concrete.This paper presents a numerical simulation of the response of SRC columns subjected to blast loading using hydrocode LS-DYNA.In the numerical model,a sophisticate concrete material model (the Concrete Damage Model) is employed with consideration of the strain rate effect and the damage accumulation.An erosion technique is adopted to model the spalling process of concrete.The possible failure modes of SRC columns are evaluated.It is observed that the failure of SRC columns subjected to blast load can generally be classified into three modes,namely,a direct failure in concrete body due to the stress wave,a transverse shear failure near the support sections due to the high shear force,and a flexural failure pertaining to large local and global deformation of the reinforcing steel.

  9. Experimental evaluation of the prevention methods for the interface between masonry infill walls and concrete columns

    Directory of Open Access Journals (Sweden)

    A. P. Tramontin

    Full Text Available Cracks that form at the interfaces between masonry structures are common uncontrolled occurrences in buildings. Numerous methods have been proposed by the construction industry to address this problem. Cracks continuously form in the joints between concrete columns and masonry infill walls. In this study, the most common methods for preventing these types of cracks were evaluated in laboratory experiments. Column masonry models were constructed using different types of joints between concrete columns and masonry infill walls, such as steel bars and steel mesh. The efficiency of each type of joint method was evaluated by performing direct tensile tests (pullout tests on the models and monitoring the evolution of the crack opening in the joint between the column and wall, as a function of load applied to the model. The results from this study indicate that the model composed of "electrowelded wire mesh without steel angles" is the best model for controlling cracking in the joints between concrete columns and masonry infill walls.

  10. 双肢缀条与缀板格构柱的经济性对比研究%Research on Economical Contrast of Latticed Columns and Battened Columns with Double Limbs

    Institute of Scientific and Technical Information of China (English)

    王永发; 谢荣凯

    2013-01-01

    以单向偏心受压双肢格构柱为研究对象,引入参量柱端压力、压力单向偏心距、柱计算长度、槽钢类型、分肢间距、缀板尺寸与间距、缀条尺寸与布置角度等.变化各参量,验算得到满足《钢结构规范》的缀条与缀板格构柱,对比两者在相同外荷载工况下的最小用钢量.分析表明,缀条柱的经济性随端部压力、压力单向偏心距和柱计算长度的增大而逐渐优于缀板柱;并且当压力和偏心距较大时,柱的计算长度对两者用钢量差值的影响较小.根据荷载工况与经济使用荷载工况边界曲线的关系,可以选用较经济的格构柱形式.研究结果可以指导设计工作中两种形式格构柱的选用.%Double limbs build-up steel columns under one-way eccentric load are studied. The parameters under study are end load, one-way eccentricity, columns' effective length, channel steel type, spacing between limbs, batten plate' s size and space, lacing bar' s size and angle. As the abovementioned parameters vary, latticed columns and battened columns are designed and verified based on Design Code for the Steel Structures. The minimum steel quantities of them are calculated and compared under the identical load condition. Latticed columns are more economic than battened columns as load, eccentricity and columns' effective length increases. In addition , columns' effective length has a little influence on difference of their steel quantities when either load or eccentricity is comparatively larger. The type of build-up steel columns, which is more economic, can be determined by comparing load condition with boundary curve of economical and applicable conditions. The design and application of double limbs build-up steel columns can be contributed.

  11. Ultrahigh carbon steels, Damascus steels, and superplasticity

    Energy Technology Data Exchange (ETDEWEB)

    Sherby, O.D. [Stanford Univ., CA (United States). Dept. of Materials Science and Engineering; Wadsworth, J. [Lawrence Livermore National Lab., CA (United States)

    1997-04-01

    The processing properties of ultrahigh carbon steels (UHCSs) have been studied at Stanford University over the past twenty years. These studies have shown that such steels (1 to 2.1% C) can be made superplastic at elevated temperature and can have remarkable mechanical properties at room temperature. It was the investigation of these UHCSs that eventually brought us to study the myths, magic, and metallurgy of ancient Damascus steels, which in fact, were also ultrahigh carbon steels. These steels were made in India as castings, known as wootz, possibly as far back as the time of Alexander the Great. The best swords are believed to have been forged in Persia from Indian wootz. This paper centers on recent work on superplastic UHCSs and on their relation to Damascus steels. 32 refs., 6 figs.

  12. 29 CFR Appendix F to Subpart R of... - Perimeter Columns: Non-Mandatory Guidelines for Complying With § 1926.756(e) To Protect the...

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Perimeter Columns: Non-Mandatory Guidelines for Complying With § 1926.756(e) To Protect the Unprotected Side or Edge of a Walking/Working Surface F Appendix F... Steel Erection Pt. 1926, Subpt. R, App. F Appendix F to Subpart R of Part 1926—Perimeter Columns:...

  13. Water Column Sonar Data Collection

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The collection and analysis of water column sonar data is a relatively new avenue of research into the marine environment. Primary uses include assessing biological...

  14. Heavy metal adsorption changes of EAF steel slag after phosphorus adsorption.

    Science.gov (United States)

    Song, Guanling; Cao, Lijing; Chen, Xiao; Hou, Wenhua; Wang, Qunhui

    2012-01-01

    A kind of electric arc furnace (EAF) steel slag was phosphated, and its isothermal and dynamic adsorptions of copper, cadmium, and lead ions were measured to determine if heavy metal adsorption changes after phosphorus adsorption. The surface area increased greatly after the slag was phosphated. Isothermal adsorption experiments showed that the theoretical Q(max) of the EAF steel slag on Cu(2+), Cd(2+), and Pb(2+) improved 59, 50, and 89% respectively after it was phosphated. Dynamic adsorption results showed that the greatest adsorption capacities of unit volume of Cu(2+), Cd(2+), and Pb(2+) were 2.2, 1.8, and 1.8 times that of the column packed with original EAF steel slag when the column was packed with phosphate EAF steel slag at the same heavy metal ion concentration. The breakthrough time, the exhaustion time and elution efficiency of the column also increased when the column was packed with phosphated EAF steel slag compared with that packed with original EAF steel slag. Phosphorus adsorption could further improve the heavy metal ion adsorption of the EAF steel slag.

  15. Mathematical Modeling of Column-Base Connections under Monotonic Loading

    Directory of Open Access Journals (Sweden)

    Gholamreza Abdollahzadeh

    2014-12-01

    Full Text Available Some considerable damage to steel structures during the Hyogo-ken Nanbu Earthquake occurred. Among them, many exposed-type column bases failed in several consistent patterns, such as brittle base plate fracture, excessive bolt elongation, unexpected early bolt failure, and inferior construction work, etc. The lessons from these phenomena led to the need for improved understanding of column base behavior. Joint behavior must be modeled when analyzing semi-rigid frames, which is associated with a mathematical model of the moment–rotation curve. The most accurate model uses continuous nonlinear functions. This article presents three areas of steel joint research: (1 analysis methods of semi-rigid joints; (2 prediction methods for the mechanical behavior of joints; (3 mathematical representations of the moment–rotation curve. In the current study, a new exponential model to depict the moment–rotation relationship of column base connection is proposed. The proposed nonlinear model represents an approach to the prediction of M–θ curves, taking into account the possible failure modes and the deformation characteristics of the connection elements. The new model has three physical parameters, along with two curve-fitted factors. These physical parameters are generated from dimensional details of the connection, as well as the material properties. The M–θ curves obtained by the model are compared with published connection tests and 3D FEM research. The proposed mathematical model adequately comes close to characterizing M–θ behavior through the full range of loading/rotations. As a result, modeling of column base connections using the proposed mathematical model can give crucial beforehand information, and overcome the disadvantages of time consuming workmanship and cost of experimental studies.

  16. FRP Composites Strengthening of Concrete Columns under Various Loading Conditions

    Directory of Open Access Journals (Sweden)

    Azadeh Parvin

    2014-04-01

    Full Text Available This paper provides a review of some of the progress in the area of fiber reinforced polymers (FRP-strengthening of columns for several loading scenarios including impact load. The addition of FRP materials to upgrade deficiencies or to strengthen structural components can save lives by preventing collapse, reduce the damage to infrastructure, and the need for their costly replacement. The retrofit with FRP materials with desirable properties provides an excellent replacement for traditional materials, such as steel jacket, to strengthen the reinforced concrete structural members. Existing studies have shown that the use of FRP materials restore or improve the column original design strength for possible axial, shear, or flexure and in some cases allow the structure to carry more load than it was designed for. The paper further concludes that there is a need for additional research for the columns under impact loading senarios. The compiled information prepares the ground work for further evaluation of FRP-strengthening of columns that are deficient in design or are in serious need for repair due to additional load or deterioration.

  17. Reinforcing the Steel Sector

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    By pushing forward mergers between steel-makers, China gears up to consolidate the large but fragmented industryIn a government effort to consolidate the crowded steel industry and position it for fierce global competition, the state-

  18. Seismic cyclic loading test of SRC columns confined with 5-spirals

    Institute of Scientific and Technical Information of China (English)

    WENG ChengChiang; YIN YenLiang; WANG JuiChen; LIANG ChingYu

    2008-01-01

    Presented herein is an experimental study on seismic resistance of rectangular steel reinforced concrete (SRC) columns confined with a new type of multi-spiral cage.The multi-spiral cage is a device of five interconnected spirals,named "5-spirals",with a large spiral at the center and four small ones at the corners.The innovation of applying the 5-spirals to SRC column is to take its superiority in concrete confinement and efficiency in automatic production for the precast con-struction industry.Four full-scale SRC columns were tested under horizontal cyclic loading.All of the tested columns were capable of sustaining a drift angle up to 6%radians.The hysteresis loops observed from the cyclic loading tests indicated that the spirally confined SRC columns demonstrated excellent performances in both strength and ductility.The test results suggested that with significant saving of the confinement steel,the newly innovated 5-spirals can be successfully applied to the precast rectangular SRC columns.

  19. Finite Element Analysis on Influence Factor of Seismic Behavior of the Concrete-Filled Steel Square Tubular Column Joints%方钢管混凝土中节点抗震性能影响因素有限元分析

    Institute of Scientific and Technical Information of China (English)

    肖丽丽

    2011-01-01

    设计了6个节点模型试件,应用有限元软件ANSYS,对低周反复荷载作用下的节点模型破坏全过程进行分析,并分析芯钢管强度、核心区混凝土强度和外钢管强度对节点滞回性能以及骨架曲线的影响.ANSYS分析结果表明:芯钢管强度和外钢管强度对节点的耗能能力有一定的影响,对节点的承载力影响不大;核心区混凝土的强度对节点的耗能能力和承载力都有一定的影响.%To research the mechanical behavior of the interior joint with core steel tube in Concrete Filled Square Steel Tubular under low reversed cyclic loading, and to explore the relevant factors of the impact of node performance, the whole destruction process of the node model under the action of low cyclic loading was analyzed in the paper based on six designs of the node, by using the finite element software ANSYS. The strength of core steel, the concrete of the core area, the strength of outside steel pipe, the Hysteretic Curve and the skeleton curve on the node model were investigated in details. The results showed that the core strength and outer steel pipe strength have a certain influence on the bearing capacity of the node, but they have little influence on of the energy capacity. And the strength of the concrete of the core area have the impact of the Energy Dissipation and the Bearing Capacity on the node model.

  20. Radiotracer Imaging of Sediment Columns

    Science.gov (United States)

    Moses, W. W.; O'Neil, J. P.; Boutchko, R.; Nico, P. S.; Druhan, J. L.; Vandehey, N. T.

    2010-12-01

    Nuclear medical PET and SPECT cameras routinely image radioactivity concentration of gamma ray emitting isotopes (PET - 511 keV; SPECT - 75-300 keV). We have used nuclear medical imaging technology to study contaminant transport in sediment columns. Specifically, we use Tc-99m (T1/2 = 6 h, Eγ = 140 keV) and a SPECT camera to image the bacteria mediated reduction of pertechnetate, [Tc(VII)O4]- + Fe(II) → Tc(IV)O2 + Fe(III). A 45 mL bolus of Tc-99m (32 mCi) labeled sodium pertechnetate was infused into a column (35cm x 10cm Ø) containing uranium-contaminated subsurface sediment from the Rifle, CO site. A flow rate of 1.25 ml/min of artificial groundwater was maintained in the column. Using a GE Millennium VG camera, we imaged the column for 12 hours, acquiring 44 frames. As the microbes in the sediment were inactive, we expected most of the iron to be Fe(III). The images were consistent with this hypothesis, and the Tc-99m pertechnetate acted like a conservative tracer. Virtually no binding of the Tc-99m was observed, and while the bolus of activity propagated fairly uniformly through the column, some inhomogeneity attributed to sediment packing was observed. We expect that after augmentation by acetate, the bacteria will metabolically reduce Fe(III) to Fe(II), leading to significant Tc-99m binding. Imaging sediment columns using nuclear medicine techniques has many attractive features. Trace quantities of the radiolabeled compounds are used (micro- to nano- molar) and the half-lives of many of these tracers are short (Image of Tc-99m distribution in a column containing Rifle sediment at four times.

  1. The steel scrap age.

    Science.gov (United States)

    Pauliuk, Stefan; Milford, Rachel L; Müller, Daniel B; Allwood, Julian M

    2013-04-02

    Steel production accounts for 25% of industrial carbon emissions. Long-term forecasts of steel demand and scrap supply are needed to develop strategies for how the steel industry could respond to industrialization and urbanization in the developing world while simultaneously reducing its environmental impact, and in particular, its carbon footprint. We developed a dynamic stock model to estimate future final demand for steel and the available scrap for 10 world regions. Based on evidence from developed countries, we assumed that per capita in-use stocks will saturate eventually. We determined the response of the entire steel cycle to stock saturation, in particular the future split between primary and secondary steel production. During the 21st century, steel demand may peak in the developed world, China, the Middle East, Latin America, and India. As China completes its industrialization, global primary steel production may peak between 2020 and 2030 and decline thereafter. We developed a capacity model to show how extensive trade of finished steel could prolong the lifetime of the Chinese steelmaking assets. Secondary steel production will more than double by 2050, and it may surpass primary production between 2050 and 2060: the late 21st century can become the steel scrap age.

  2. Blast Protection Shelter by Using Hollow Steel Filled with Recycled Concrete

    Institute of Scientific and Technical Information of China (English)

    LI Jianchun; HUANG Xin; MA Guowei

    2008-01-01

    Under extreme loading condition, a shelter will provide a safe place to protect people from injury caused by blast wave and fragments.In order to save resource and reuse waste materials, a new design concept for blast protection shelter was explored.The new construction was composed of I-section steel panel or C-channel steel panel filled with recycled concrete aggregate.The compaction process of the recycled concrete aggregate filled in the steel construction was experimentally investigated.A single storey shelter based on the proposed design concept was numerically simulated by using LS-DYNA software.In the 3D numerical model, three walls were designed using I-section steel and one wall using C-channel steel, and all of the four walls were filled with recycled concrete aggregate.The penetration analysis was done by using ConWep.Some penetration tests were also carried out by using a gas gun.It is found that the proposed shelter based on the design concept is effective for blast protection.

  3. Design of Reforma 509 with High Strength Steel

    Science.gov (United States)

    Smith, Stuart; Whitby, William; Easton, Marc

    Reforma 509 is a high-rise building located in the heart of the Central Business District of Mexico City. The building is comprised of office, hotel, residential and parking and forms part of a cluster of tall buildings in the area. If completed today, Reforma 509 would be the tallest building in Mexico, at 238m. All of the building's gravity and lateral (wind and seismic) loads are carried by an architecturally expressed perimeter frame that is formed from highly efficient Steel Reinforced Concrete (SRC) columns coupled together by steel tube perimeter bracing. This paper investigates the implications of substituting a grade 50 (fy=345 MPa) carbon steel with a higher strength micro-alloyed grade 70 (fy=480 MPa) steel in the design of Reforma 509.

  4. Seismic Behavior of Fatigue-Retrofitted Steel Frame Piers

    Directory of Open Access Journals (Sweden)

    Kinoshita K.

    2013-01-01

    Full Text Available Fatigue retrofit works have been conducted on severely fatigue damaged beam-to-column connections of existing steel frame bridge piers in Japan. It is clear that retrofit works provides additional stiffness but the significance on the seismic behavior of steel frame piers is not clear. Since fatigue retrofit works have become prevalent, the effect of fatigue retrofit works on the seismic behavior of steel frame piers need to be understood. The objective of this study is therefore to investigate these effects of the retrofit work, especially installation of bolted splices, which is the most common technique. Elasto-plastic finite element earthquake response analyses were carried out. It is shown that the existence of bolted splices may increase seismic demand on the piers when plastic hinge zone is located on the beam. In addition, longer bolted splices using low yield strength steel are proposed to overcome this problem and are shown to give beneficial effects.

  5. A cyclic loading model for beam-to-column web connection

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-bo; XIE li-li; SHAO Yong-song

    2008-01-01

    A finite element analysis of the beam-to-column web connection with H-shaped columns was performed using the ANSYS computer program.Based on the finite element analysis and theoretical analysis,a simplified model was developed to describe the cyclic loading behavior of beam-to-columns web connection in steel moment resisting frames,considering both bending and shear deformation modes of the beam flange plate.Several issues appearing to merit further researches were identified in the process of developing this model,such as the effect of beam flange plate on beam-to-column web connection stiffness and strength.A reasonable agreement was achieved between model predictions and finite element data,which verified the feasibihty of the proposed model.

  6. Methodological analysis of gamma tomography system for large random packed columns

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez, Pablo A.S.; De Mesquita, Carlos H. [Instituto de Pesquisas Energeticas e Nucleares-IPEN/CNEN-SP, Prof. Lineu Prestes, 2242-Cidade Universitaria, 05508-900, Sao Paulo (Brazil); LeRoux, Galo A.C. [Departamento de Engenharia Quimica, Escola Politecnica da Universidade de Sao Paulo, Prof. Luciano Gualberto, Trav. 3, 380-Cidade Universitaria, 05508-900, Sao Paulo (Brazil); Hamada, Margarida M. [Instituto de Pesquisas Energeticas e Nucleares-IPEN/CNEN-SP, Prof. Lineu Prestes, 2242-Cidade Universitaria, 05508-900, Sao Paulo (Brazil)], E-mail: mmhamada@ipen.br

    2010-04-15

    Gamma ray tomography experiments have been carried out to detect spatial patterns in the porosity in a 0.27 m diameter column packed with steel Rashig rings of different sizes: 12.6, 37.9, and 76 mm. using a first generation CT system. A fast Fourier transform tomographic reconstruction algorithm has been used to calculate the spatial variation over the column cross section. Cross-sectional gas porosity and solid holdup distribution were determinate. The values of cross-sectional average gas porosity were {epsilon}=0.849, 0.938 and 0.966 for the 12.6, 37.9, and 76 mm rings, respectively. Radial holdup variation within the packed bed has been determined. The variation of the circumferentially averaged gas holdup in the radial direction indicates that the porosity in the column wall region is a somewhat higher than that in the bulk region, due to the effect of the column wall.

  7. Assessment of Methods for Development of Confinement Model of Low Strength Reinforced Concrete Columns: A Review

    Directory of Open Access Journals (Sweden)

    Asif Ali

    2016-10-01

    Full Text Available Reinforced Concrete is composed of concrete and steel, where compressive strength of concrete and tensile strength of steel are utilized to achieve the required member strength. The high tensile property of steel is thus used to confine and increase compressive strength and ductility of RC columns. Confined concrete is defined as concrete that is restrained laterally by any internal or external means i.e. reinforcement consisting of steel stirrups or spirals, Fiber Reinforced Polymer (FRP, Circular Concrete Filled Steel Tube, RC shell jacketing etc. An appropriate amount of confinement increases the strength, ductility and energy dissipation capacity of RC members. This paper focuses on finding out strength and ductility enhancement of low strength RC columns by reinforcement using existing confinement models. Confinement models are stress-strain curves developed for concrete compression member under uniaxial or dynamic loading, confined with transverse reinforcement. Different models along with their experimental validations are discussed in this paper to get state of the art knowledge of confinement studies possible for low strength concrete. The models recommended from this study are used to evaluate existing structures made with low strength concrete

  8. Column Holdup Formula of Soil Solute Transport

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The shortcomings of the present two formulae for describing column holdup are analyzed and deductions are made to find a new formula. The column holdup, Hw, described by the new formula is dimensional,and related to soil solute transport kinesis and column physical properties. Compared with the other two column holdups, Hw is feasible to describe dimensional column holdup during solute transport process. The relationships between Hw and retardation factor, R, in different solute transport boundary conditions are established.

  9. Numerical Simulation of Dynamic Response and Collapse for Steel Frame Structures Subjected to Blast Load

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiuhua; DUAN Zhongdong; ZHANG Chunwei

    2008-01-01

    The progressive collapse of steel frame structures under the blast load was investigated using LS-DYNA.The multi-material Eulerian and Lagrangian coupling algorithm was adopted.A fluid-structure coupling finite element model was established which consists of Lagrange element for simulating steel frame structures and concrete ground,multiple ALE element for simulating air and TNT explosive material.Numerical simulations of the blast pressure wave propagation,structural dynamic responses and deformation,and progressive collapse of a five-story steel frame structure in the event of an explosion near above ground were performed.The numerical analysis showed that the Lagrangian and Eulerian coupling algorithm gave good simulations of the shock wave propagation in the mediums and blast load effects on the structure.The columns subjected to blast load may collapse by shear yielding rather than by flexural deformation.The columns and joints of steel beam to column in the front steel frame structure generated enormous plastic deformation subjected to intensive blast waves,and columns lost carrying capacity,subsequently leading to the collapse of the whole structure.The approach coupling influence between structural deformation and fluid load well simulated the progressive collapse process of structures,and provided an effective tool for analyzing the collapse mechanism of the steel frame structure under blast load.

  10. Partially saturated granular column collapse

    Science.gov (United States)

    Turnbull, Barbara; Johnson, Chris

    2017-04-01

    Debris flows are gravity-driven sub-aerial mass movements containing water, sediments, soil and rocks. These elements lead to characteristics common to dry granular media (e.g. levee formation) and viscous gravity currents (viscous fingering and surge instabilities). The importance of pore fluid in these flows is widely recognised, but there is significant debate over the mechanisms of build up and dissipation of pore fluid pressure within debris flows, and the resultant effect this has on dilation and mobility of the grains. Here we specifically consider the effects of the liquid surface in the flow. We start with a simple experiment constituting a classical axisymmetric granular column collapse, but with fluid filling the column up to a depth comparable to the depth of grains. Thus, as the column collapses, capillary forces may be generated between the grains that prevent dilation. We explore a parameter space to uncover the effects of fluid viscosity, particle size, column size, aspect ratio, grain shape, saturation level, initial packing fraction and significantly, the effects of fine sediments in suspension which can alter the capillary interaction between wetted macroscopic grains. This work presents an initial scaling analysis and attempts to relate the findings to current debris flow modelling approaches.

  11. Compression Behavior of Confined Columns with High-Volume Fly Ash Concrete

    Directory of Open Access Journals (Sweden)

    Sung-Won Yoo

    2017-01-01

    Full Text Available The use of fly ash in ordinary concrete provides practical benefits to concrete structures, such as a gain in long-term strength, reduced hydration heat, improved resistance to chloride, and enhanced workability. However, few studies with high-volume fly ash (HVFA concrete have been conducted that focus on the structural applications such as a column. Thus, there is a need to promote field applications of HVFA concrete as a sustainable construction material. To this end, this study investigated the compressive behavior of reinforced concrete columns that contain HVFA with a 50 percent replacement rate. Six columns were fabricated for this study. The study variables were the HVFA replacement rate, tied steel ratio, and tie steel spacing. The computed ultimate strength by the American Concrete Institute (ACI code conservatively predicted the measured values, and, thus, the existing equation in the ACI code is feasible for confined RC columns that contain HVFA. In addition, an analysis model was calibrated based on the experimental results and is recommended for predicting the stress-strain relationship of confined reinforced concrete columns that contain HVFA.

  12. Boundary effects in welded steel moment connections

    Science.gov (United States)

    Lee, Kyoung-Hyeog

    Unprecedented widespread failure of welded moment connections in steel frames caused by the 1994 Northridge and the 1995 Kobe earthquakes have alarmed the engineering communities throughout the world. Welded moment connections in steel frames have been traditionally designed by using the classical beam theory which leads to assumptions that the flanges transfer moment while the web connection primarily resists the shear force. However, this study shows that the magnitude and direction of the principal stresses in the connection region are better approximated by using truss analogy rather than the classical beam theory. Accordingly, both the bending moment and the shear force are transferred across the connection near the beam flanges through diagonal strut action. Thus, the beam flange region of the traditionally designed connection is overloaded. This conclusion explains, to a large extent, the recently observed steel moment connection failures. In this study, detailed finite element analyses were carried out for a representative beam-to-column subassemblage with fully welded connection. The stress distribution in the beam web and flanges in the vicinity of the connection were closely studied. The factors responsible for stress redistribution and concentration were identified by using fundamental principles of mechanics. It was concluded that peak resultant stresses can exceed the values used in simple design calculations by large margins. Using the finite element analysis results and the truss analogy to establish a realistic load path in the connection, a practical and more rational analysis and design procedure was developed. The proposed design procedure and the new connection details were successfully validated through cyclic load testing of a nearly full size specimen. The truss model represented the force transmission around the beam-to-column moment connection region very well. Results of the finite element analyses and the laboratory testing showed

  13. Strengthening of defected beam-column joints using CFRP.

    Science.gov (United States)

    Mahmoud, Mohamed H; Afefy, Hamdy M; Kassem, Nesreen M; Fawzy, Tarek M

    2014-01-01

    This paper presents an experimental study for the structural performance of reinforced concrete (RC) exterior beam-column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP). The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam-column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM) CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity.

  14. Strengthening of defected beam–column joints using CFRP

    Directory of Open Access Journals (Sweden)

    Mohamed H. Mahmoud

    2014-01-01

    Full Text Available This paper presents an experimental study for the structural performance of reinforced concrete (RC exterior beam–column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP. The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam–column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity.

  15. Strengthening of defected beam–column joints using CFRP

    Science.gov (United States)

    Mahmoud, Mohamed H.; Afefy, Hamdy M.; Kassem, Nesreen M.; Fawzy, Tarek M.

    2013-01-01

    This paper presents an experimental study for the structural performance of reinforced concrete (RC) exterior beam–column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP). The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam–column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM) CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity. PMID:25685473

  16. Columns

    Institute of Scientific and Technical Information of China (English)

    于晓悠; 丁燕燕; 韩多妮; Ray; Carrie; 未冉

    2010-01-01

    <正>New York Whitney艺术双年展今年第75届纽约Whitney双年展不设题目,但以"2010"指示策展方向,继续以发掘年轻艺术家、展示创作实验为目标。参展的55位艺术家,最年轻的是23岁摄影师Tam Tran,最老资历的是75岁的概念艺术家Lorraine O’Grady。这届的另一先创性,是每位艺术家只限一件或一个系列的作品,避免了去届双年展的"小型个人回顾展"现象,而五层楼的展场各有特色,如录像及短片将独立于三楼展出,而美术馆馆藏则移师五楼。这届双年展由著名的意大利策展人Francesco Bonami联同助手Gary Carrion-Murayarn共同制作,两位策展人说明,双年展的重要性是预示未来,创新及前瞻性依然是取决原则。

  17. Columns

    Institute of Scientific and Technical Information of China (English)

    Carrie Tsang; 丁燕燕; 韩多妮; RAY

    2009-01-01

    <正>Paris承诺的展现33岁的墨西哥艺术家Mario Garcia Torres是近年国际艺坛炙手可热的新星,他以录象、摄影、幻灯及装置为创作形式,透过个人视点及独特演绎手法来重新思考历史。他是一个思考型艺术家,同时又是一个淘气的大孩子,作品往往反映了他的双重性格——嬉戏中带有深沉的历史感。这次是GarciaTorres首次在法国的国家博物馆举行展览,整合出版了他过往两年间在

  18. Ultrahigh Carbon Steel.

    Science.gov (United States)

    1984-10-01

    Steels have been utilized to prepare compacted powders of white cast iron (2 to 3%C) which exhibit superplastic be- havior at 650 0C and which are ductile ...strength and ductility than many of these commercially-avail- able steels. In particular, austempered fine-grained UHC steels exhibit good co7,binations of... Ductility of Rapidly Solidified White Cast Irons ", Powd. Metall., 26 (1983), pp. 155-160. (29) L. E. Eiselstein, 0. A. Ruano, J. Wadsworth, and 0. D

  19. Ultrahigh Carbon Steels

    Science.gov (United States)

    Sherby, O. D.; Oyama, T.; Kum, D. W.; Walser, B.; Wadsworth, J.

    1985-06-01

    Recent studies and results on ultrahigh carbon (UHC) steels suggest that major development efforts on these steels are timely and that programs to evaluate prototype structural components should be initiated. These recent results include: the development of economical processing techniques incorporating a divorced eutectoid transformation, the improvement of room temperature strength and ductility by heat treatment, the enhancement of superplastic properties through dilute alloying with silicon, and the attainment of exceptional notch impact strength in laminated UHC steel composites manufactured through solid state bonding. The unique mechanical properties achieved in UHC steels are due to the presence of micron-size fer-rite grains and ultrafine spheroidized carbides.

  20. Optimal design of steel portal frames based on genetic algorithms

    Institute of Scientific and Technical Information of China (English)

    Yue CHEN; Kai HU

    2008-01-01

    As for the optimal design of steel portal frames, due to both the complexity of cross selections of beams and columns and the discreteness of design variables, it is difficult to obtain satisfactory results by traditional optimization. Based on a set of constraints of the Technical Specification for Light-weighted Steel Portal Frames of China, a genetic algorithm (GA) optimization program for portal frames, written in MATLAB code, was proposed in this paper. The graph user interface (GUI) is also developed for this optimal program, so that it can be used much more conveniently. Finally, some examples illustrate the effectiveness and efficiency of the genetic-algorithm-based optimal program.

  1. Modeling of column apparatus processes

    CERN Document Server

    Boyadjiev, Christo; Boyadjiev, Boyan; Popova-Krumova, Petya

    2016-01-01

    This book presents a new approach for the modeling of chemical and interphase mass transfer processes in industrial column apparatuses, using convection-diffusion and average-concentration models. The convection-diffusion type models are used for a qualitative analysis of the processes and to assess the main, small and slight physical effects, and then reject the slight effects. As a result, the process mechanism can be identified. It also introduces average concentration models for quantitative analysis, which use the average values of the velocity and concentration over the cross-sectional area of the column. The new models are used to analyze different processes (simple and complex chemical reactions, absorption, adsorption and catalytic reactions), and make it possible to model the processes of gas purification with sulfur dioxide, which form the basis of several patents.

  2. Comparison of drug substance impurity profiles generated with extended length columns during packed-column SFC.

    Science.gov (United States)

    Roston, D A; Ahmed, S; Williams, D; Catalano, T

    2001-10-01

    The current study assesses the effect of extending column length during gradient packed column sub/supercritical fluid chromatography (PCSFC) experiments on the detection of known and unknown impurities in a drug substance sample. Quantitative drug substance impurity profiles were generated and compared using multiple column PCSFC and HPLC conditions. Also, chromatographic figures of merit were estimated and compared for components of a standard mixture during PCSFC experiments, which used one column, four columns, and six columns in series.

  3. Novel hybrid FRP tubular columns for sustainable mining infrastructure:Recent research at University of Wollongong

    Institute of Scientific and Technical Information of China (English)

    Yu Tao; Remennikov Alex M.

    2014-01-01

    This paper introduces, for applications in the mining industry, an innovative hybrid column form which consists of an inner steel tube, an outer fibre-reinforced polymer (FRP) tube and an annular concrete infill between them. The two tubes may be concentrically placed to produce a section form more suitable for columns, or eccentrically placed to produce a section form more suitable for beams. The FRP is combined with steel and concrete in these hybrid structural members in such a way that the advantages of FRP are appropriately exploited while its disadvantages are minimized. As a result, these hybrid members pos-sess excellent corrosion resistance as well as excellent ductility and seismic resistance. This paper sum-marizes existing research on this new form of structural members, and discusses their potential applications in mining infrastructure before presenting a summary of the recent and current studies at University of Wollongong (UOW) on their structural behaviour and design.

  4. Beam Studies with Electron Columns

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, V.; Valishev, A.; Kuznetsov, G.; /Fermilab; Kamerdzhiev, V.; /Julich, Forschungszentrum; Romanov, A.; /Novosibirsk, IYF

    2009-04-01

    We report preliminary results of experimental studies of 'electron columns' in the Tevatron and in a specialized test setup. In the Tevatron, a beam of 150 GeV protons ionizes residual gas and ionization electrons are stored in an electrostatic trap immersed into strong longitudinal magnetic field. Shifts of proton betatron frequencies are observed. In the test setup, we observe effects pointing to accumulation and escape of ionization electrons.

  5. Water Column Methylation in Estuaries

    Science.gov (United States)

    Schartup, A. T.; Calder, R.; Soerensen, A. L.; Mason, R. P.; Balcom, P. H.; Sunderland, E. M.

    2014-12-01

    Methylmercury (MeHg) is a neurotoxin that bioaccumulates in aquatic food webs and affects humans and wildlife through fish consumption. Many studies have measured active methylation/demethylation in ocean margin sediments but few have reported similar rates for the marine water column. This presentation will review available evidence for water column methylation in estuaries, including new experimental measurements of methylation/demethylation rates from a deep subarctic fjord in Labrador Canada collected in Spring and Fall of 2012-2013. We used these and other data to construct a mass budget for MeHg in the estuary and show that water column methylation (with rates ranging from 1.5 to 2.8 % day-1), is the largest contributor, followed by inputs from rivers (4.9 mol year-1), to the in situ pool of MeHg available for uptake by biota. By contrast, the sediment in this system is a net sink for MeHg (-1.5 mol year-1). We discuss the relationship between observed MeHg and other ancillary environmental factors (organic carbon, sulfur and nutrients) as well as implications for the response time of fish to future changes in mercury inputs.

  6. Modern Steel Framed Schools.

    Science.gov (United States)

    American Inst. of Steel Construction, Inc., New York, NY.

    In view of the cost of structural framing for school buildings, ten steel-framed schools are examined to review the economical advantages of steel for school construction. These schools do not resemble each other in size, shape, arrangement or unit cost; some are original in concept and architecture, and others are conservative. Cost and…

  7. Experimental study on seismic behaviors of steel-concrete composite frames

    Institute of Scientific and Technical Information of China (English)

    戚菁菁; 蒋丽忠

    2015-01-01

    Steel-concrete composite frames are seeing increased use in earthquake region because of their excellent structural characteristics, including high strength, stiffness, and good ductility. However, there exist gaps in the knowledge of seismic behavior and the design provisions for these structures. In order to better understand the seismic behaviors of composite frame systems, eight steel-concrete composite frames were designed. These composite frames were composed of steel-concrete composite beams and concrete filled steel tube columns. The axial compression ratio of column, slenderness ratio and linear stiffness ratio of beam to column were selected as main design parameters. The low reversed cyclic loading tests of composite frame system were carried out. Based on test results, the seismic behaviors of composite frames such as failure mode, hysteresis curve, strength degradation, rigidity degradation, ductility and energy dissipation were studied. Known from the test phenomenon, the main cause of damage is the out-of-plane deformation of steel beam and the yielding destruction of column heel. The hysteretic loops of composite frame appear a spindle shape and no obvious pinch phenomenon. The results demonstrate that this type of composite frame has favorable seismic behaviors. Furthermore, the effects of design parameters on seismic behaviors were also discussed. The results of the experiment show that the different design parameter has different influence rule on seismic behaviors of composite frame.

  8. Clean Production of Steel and Refractories in China's Steel Industry

    Institute of Scientific and Technical Information of China (English)

    SU Tiansen

    2002-01-01

    The paper describes the importance of clean production of steel and the relationships amongst sustaining development of steel industry, environment protection and the role of refractories in the clean production of steel. The main achievements and main shortcomings in the clean production of China' s steel industry have been reviewed together with the introduction of the policy supporting system and the future development of clean production in China' s steel industry.

  9. Mechanical behavior of confined self-compacting reinforced concrete circular columns under concentric axial loading

    Directory of Open Access Journals (Sweden)

    Fouad Khairallah

    2013-12-01

    Full Text Available While there is abundant research information on ordinary confined concrete, there are little data on the behavior of Self-Compacting Concrete (SCC under such condition. Due to higher shrinkage and lower coarse aggregate content of SCC compared to that of Normal Concrete (NC, its composite performance under confined conditions needs more investigation. This paper has been devoted to investigate and compare the mechanical behavior of confined concrete circular columns cast with SCC and NC under concentric axial loading. The parameters affecting are including concrete compressive strength and confinement configuration. Twenty column specimens were casted and confined using four confinement techniques, CFRP wrap, FRP tube, GFRP wrap, and spiral steel hoops. The performance of the tested column specimens is evaluated based on mode of failure, load–displacement curve, stress–strain characteristics, ultimate strength, ductility, and degree of confinement.

  10. Steel: Price and Policy Issues

    Science.gov (United States)

    2006-08-31

    Inland Steel. He had also acquired a major Mexican producer, the integrated steel works on the Pacific coast at Lazaro Cardenas . But his major coup...Steel-Producing Countries Launch Talks on Banning Subsidies at OECD Meeting” (Dec. 20, 2002). 76 Nancy E. Kelly, “Steel Talks to Kick Off in Paris, Six

  11. Intrinsic advantages of packed capillaries over narrow-bore columns in very high-pressure gradient liquid chromatography.

    Science.gov (United States)

    Gritti, Fabrice; McDonald, Thomas; Gilar, Martin

    2016-06-17

    250μm×100mm fused silica glass capillaries were packed with 1.8μm high-strength silica (HSS) fully porous particles. They were prepared without bulky stainless steel endfittings and metal frits, which both generate significant sample dispersion. The isocratic efficiencies and gradient peak capacities of these prototype capillary columns were measured for small molecules (n-alkanophenones) using a home-made ultra-low dispersive micro-HPLC instrument. Their resolution power was compared to that of standard 2.1mm×100mm very high-pressure liquid chromatography (vHPLC) narrow-bore columns packed with the same particles. The results show that, for the same column efficiency (25000 plates) and gradient steepness (0.04min(-1)), the peak capacity of the 250μm i.d. capillary columns is systematically 15-20% higher than that of the 2.1mm i.d. narrow-bore columns. A validated model of gradient chromatography enabled one to predict accurately the observed peak capacities of the capillary columns for non-linear solvation strength retention behavior and under isothermal conditions. Thermodynamics applied to the eluent quantified the temperature difference for the thermal gradients in both capillary and narrow-bore columns. Experimental data revealed that the gradient peak capacity is more affected by viscous heating than the column efficiency. Unlike across 2.1mm i.d. columns, the changes in eluent composition across the 250μm i.d. columns during the gradient is rapidly relaxed by transverse dispersion. The combination of (1) the absence of viscous heating and (2) the high uniformity of the eluent composition across the diameter of capillary columns explains the intrinsic advantage of capillary over narrow-bore columns in gradient vHPLC.

  12. Elastic stability of non-uniform columns

    Science.gov (United States)

    Lee, S. Y.; Kuo, Y. H.

    1991-07-01

    A simple and efficient method is proposed to investigate the elastic stability of three different tapered columns subjected to uniformly distributed follower forces. The influences of the boundary conditions and taper ratio on critical buckling loads are investigated. The critical buckling loads of columns of rectangular cross section with constant depth and linearly varied width ( T1), constant width and linearly varied depth ( T2) and double taper ( T3) are investigated. Among the three different non-uniform columns considered, taper ratio has the greatest influence on the critical buckling load of column T3 and the lowest influence on that of column T1. The types of instability mechanisms for hinged-hinged and cantilever non-uniform columns are divergence and flutter respectively. However, for clamped-hinged and clamped-clamped non-uniform columns, the type of instability mechanism for column T1 is divergence, while that for columns T2 and T3 is divergence only when the taper ratio of the columns is greater than certain critical values and flutter for the rest value of taper ratio. When the type of instability mechanism changes from divergence to flutter, there is a finite jump for the critical buckling load. The influence of taper ratio on the elastic stability of cantilever column T3 is very sensitive for small values of the taper ratio and there also exist some discontinieties in the critical buckling loads of flutter instability. For a hinged-hinged non-uniform column ( T2 or T3) with a rotational spring at the left end of the column, when the taper ratio is less than the critical value the instability mechanism changes from divergence to flutter as the rotational spring constant is increased. For a clamped-elastically supported non-uniform column, when the taper ratio is greater than the critical value the instability mechanism changes from flutter to divergence as the translational spring constant is increased.

  13. Advanced Design of Composite Steel-Concrete Structural element

    Directory of Open Access Journals (Sweden)

    Dr. D. R. Panchal

    2014-07-01

    Full Text Available Composite framing system consisting of steel beams acting interactively with metal deck-concrete slab and concrete encased composite columns, has been as a viable alternative to the conventional steel or reinforced concrete system in the high-rise construction. However, in Indian context, it is comparatively new and no appropriate design codes are available for the same. Complications in the analysis and design of composite structures have led numerous researchers to develop simplified methods so as to eliminate a number of large scale tests needed for the design. In the present work, a simplified method of composite slabs, beams and columns design is used and software is developed with pre- and post- processing facilities in VB.NET. All principal design checks are incorporated in the software. The full and partial shear connection and the requirement for transverse reinforcement are also considered. To facilitate direct selection of steel section, a database is prepared and is available at the back end with the properties of all standard steel sections. Screen shots are included in the paper to illustrate the method employed for selecting the appropriate section and shear connectors and thus to verify the design adequacy.

  14. Produced fluids separation using a coalascer column

    Energy Technology Data Exchange (ETDEWEB)

    Renouf, G.; Soveran, D.; Soveran, L. [Saskatchewan Research Council, Saskatoon, SK (Canada)

    2005-07-01

    This paper reports the results of a laboratory study in which a coalescer column was used to successfully remove water from produced heavy oil emulsions. The coalescer column is a simple, inexpensive, and environmentally friendly technology that can improve basic sediment and water values after 4 hours of settling time by about 38 per cent. The laboratory study tested the use of the column, and the effects of column length, column packing size, temperature, flow rate, demulsifier concentration, and water addition. More than 100 tests were conducted and 24 pairs of tests compared the treating effects with and without the column. The use of the coalescer column in the treatment facility resulted in a a reduction of demulsifier concentration from 250 ppm to 70 ppm, translating to an annual cost savings of $320,000 to $1,100,000 per battery. Incorporating the coalescer column also allowed operators to reduce both temperatures and demulsifier concentrations. The column also promoted faster treating. Water droplets grew by as much as 34 per cent, suggesting that treating time could be faster by 21 to 80 per cent. It was concluded that the coalescer column was very successful at improving water removal from heavy oil battery emulsions. 22 refs., 9 tabs., 7 figs.

  15. Column flotation testing at Suncor Energy Inc.

    Energy Technology Data Exchange (ETDEWEB)

    Cleyle, P.; Lee, L. [Suncor Energy Inc. Oil Sands, Fort McMurray, AB (Canada)

    2006-07-01

    The operations at Suncor's primary extraction plant were reviewed with reference to the column flotation process and the history of column flotation testing at Suncor. Tertiary bitumen recovery processes were also reviewed. In March and August 2005, an in-plant pilot scale column flotation test was conducted at Suncor's Millennium Primary Extraction plant near Fort McMurray, Alberta. The purpose was to evaluate the feasibility of using column flotation for tertiary bitumen recovery from cyclone overflow. The test was performed in a 4 ft diameter by 25 ft high column to determine the effects of column feed flow rate, froth wash water supply, and froth depth. The feed ranged from 0.14 to 3.79 wt per cent bitumen. Feed flow rate ranged from 59 to 237 USGPM. The test results indicated that wash water reduced froth mineral content. Increasing the wash water did not make any difference in mineral rejection. Although bitumen upgrading improved when the test column was operated at a deeper froth depth, the mineral content was not reduced. Both mechanical cell and flotation column tailings samples were collected in the flotation column tests. The average tailings composition for the last cell in the tertiary mechanical bank was 0.22 per cent bitumen, 12.10 per cent mineral, and 87.66 per cent water. At an average test column feed rate of 158 USGPM, the average tailings composition was 0.23 per cent bitumen, 12.13 per cent mineral, and 87.62 per cent water. It was concluded that flotation columns are capable of producing a tailings product similar to that of the tertiary mechanical bank. Therefore, it is feasible to use flotation columns as an alternative to mechanical cells. In fact, since there are no rotating parts requiring off-line maintenance work, flotation columns may be a better alternative from a maintenance and operations perspective. tabs., figs.

  16. Comparison of the effect of grounding the column wall in gas-solid fluidized beds on electrostatic charge generation

    Energy Technology Data Exchange (ETDEWEB)

    Sowinski, Andrew; Mayne, Antonio; Javed, Bassam; Mehrani, Poupak, E-mail: poupak.mehrani@uottawa.ca [University of Ottawa, Chemical and Biological Engineering Department, 161 Louis Pasteur St., Ottawa, Ontario, K1N 6N5 (Canada)

    2011-06-23

    In gas-solid fluidized beds as particles are fluidized, they continuously come into contact with other particles, as well as the fluidization column wall. This generates electrostatic charges by means of triboelectrification and frictional charging, leading to particle agglomeration, reactor wall fouling, and eventually process downtime and large financial losses. Grounding the fluidization column has been considered as a means of helping electrostatic charge dissipation within fluidized beds; however, in industrial applications despite the process vessels being grounded, the electrostatic problem still persists. This work focused on the effect of fluidization column grounding on particle wall fouling. Experiments were conducted in an atmospheric system consist of a 0.1 m in diameter carbon steel fluidization column. The mass and charge-to-mass ratio (q/m) of the particles that remained adhered to the column wall upon the completion of one hour fluidization period were measured in an electrically isolated and grounded columns to quantitatively determine the amount of reactor wall fouling. Polyethylene particles with different particle size ranges (300- 1000 {mu}m) were fluidized with extra dry air at 1.5 times their respective minimum fluidization velocity (u{sub mf}). Results obtained in the grounded fluidization column were not significantly different from those in the isolated column for all particle size ranges tested where the particles mass collected and q/m and were found to be generally similar.

  17. Oscillating water column structural model

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, Guild [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jepsen, Richard Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gordon, Margaret Ellen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    An oscillating water column (OWC) wave energy converter is a structure with an opening to the ocean below the free surface, i.e. a structure with a moonpool. Two structural models for a non-axisymmetric terminator design OWC, the Backward Bent Duct Buoy (BBDB) are discussed in this report. The results of this structural model design study are intended to inform experiments and modeling underway in support of the U.S. Department of Energy (DOE) initiated Reference Model Project (RMP). A detailed design developed by Re Vision Consulting used stiffeners and girders to stabilize the structure against the hydrostatic loads experienced by a BBDB device. Additional support plates were added to this structure to account for loads arising from the mooring line attachment points. A simplified structure was designed in a modular fashion. This simplified design allows easy alterations to the buoyancy chambers and uncomplicated analysis of resulting changes in buoyancy.

  18. Glass Stronger than Steel

    Science.gov (United States)

    Yarris, Lynn

    2011-03-28

    A new type of damage-tolerant metallic glass, demonstrating a strength and toughness beyond that of steel or any other known material, has been developed and tested by a collaboration of researchers from Berkeley Lab and Caltech.

  19. Life after Steel

    Science.gov (United States)

    Mangan, Katherine

    2013-01-01

    Bobby Curran grew up in a working-class neighborhood in Baltimore, finished high school, and followed his grandfather's steel-toed bootprints straight to Sparrows Point, a 3,000-acre sprawl of industry on the Chesapeake Bay. College was not part of the plan. A gritty but well-paying job at the RG Steel plant was Mr. Curran's ticket to a secure…

  20. Performance Steel Castings

    Science.gov (United States)

    2012-09-30

    alloys , foundry, muzzle brake, supply center, tooling, sources Notice Distribution Statement A Format Information Report created in Microsoft Word...Development of Sand Properties 103 Advanced Modeling Dataset.. 105 High Strength Low Alloy (HSLA) Steels 107 Steel Casting and Engineering Support...University, University of Northern Iowa, Non- Ferrous Founders’ Society, QuesTek, buyCASTINGS.com, Spokane Industries, Nova Precision Casting, Waukesha

  1. Study on a continuous heat integrated distillation column

    Energy Technology Data Exchange (ETDEWEB)

    Glenchur, T.; Govind, R.

    1987-12-01

    A novel continuous heat integrated distillation column called a concentric column has been studied using computer simulation. It is shown that a concentric column is a novel implementation of a thermodynamically reversible distillation column and has a lower energy loss than an ordinary distillation column. Their studies show that a concentric column has reduced column height, since the stripping section is configured concentrically around the rectifying section, and uses less utilities than a conventional column.

  2. The jet flotation column control system

    Energy Technology Data Exchange (ETDEWEB)

    Xu Zhiqiang; Ming Shangzhi; Liu Lijian; Huangfu Jinghua; Huo Sen; Zhang Rongzeng [China Univ. of Mining and Technology, Beijing (China). Mineral Processing Dept.; Yang Hongjun [Hebi Coal Mine Administrative (China)

    1998-12-31

    Compared with the conventional mechanical flotation column, the jet flotation column has the advantages of high selectivity of separation, low investment and production cost, low floor space requirement, low dosage of reagent, easy control; it is more suitable to process fine particles. Recently, many new types of flotation columns have been developed with new methods. Mineral Processing Dept., China University of Mining and Technology (Beijing) designed an aerated, double-jet flotation column in the lab and the industrial trial will be put into operation. One of the significant characteristics of the new type of flotation column is high selectivity of separation, fast bubble mineralization speed. As it is sensitive to various factors, a control system for flotation column has been developed to stabilize the working condition, and this set of control system has been operated in the lab experiment.

  3. Novel hybrid columns made of ultra-high performance concrete and fiber reinforced polymers

    Science.gov (United States)

    Zohrevand, Pedram

    The application of advanced materials in infrastructure has grown rapidly in recent years mainly because of their potential to ease the construction, extend the service life, and improve the performance of structures. Ultra-high performance concrete (UHPC) is one such material considered as a novel alternative to conventional concrete. The material microstructure in UHPC is optimized to significantly improve its material properties including compressive and tensile strength, modulus of elasticity, durability, and damage tolerance. Fiber-reinforced polymer (FRP) composite is another novel construction material with excellent properties such as high strength-to-weight and stiffness-to-weight ratios and good corrosion resistance. Considering the exceptional properties of UHPC and FRP, many advantages can result from the combined application of these two advanced materials, which is the subject of this research. The confinement behavior of UHPC was studied for the first time in this research. The stress-strain behavior of a series of UHPC-filled fiber-reinforced polymer (FRP) tubes with different fiber types and thicknesses were tested under uniaxial compression. The FRP confinement was shown to significantly enhance both the ultimate strength and strain of UHPC. It was also shown that existing confinement models are incapable of predicting the behavior of FRP-confined UHPC. Therefore, new stress-strain models for FRP-confined UHPC were developed through an analytical study. In the other part of this research, a novel steel-free UHPC-filled FRP tube (UHPCFFT) column system was developed and its cyclic behavior was studied. The proposed steel-free UHPCFFT column showed much higher strength and stiffness, with a reasonable ductility, as compared to its conventional reinforced concrete (RC) counterpart. Using the results of the first phase of column tests, a second series of UHPCFFT columns were made and studied under pseudo-static loading to study the effect of column

  4. REVERSAL CYCLIC LOADING TEST OF REINFORCED CONCRETE COLUMN WITH HIGH DENSITY LONGITUDINAL REINFORCEMENT CONFINED BY SPIRAL REINFORCEMENT

    Science.gov (United States)

    Ohba, Mitsuaki; Sato, Akiko; Ishibashi, Tadayoshi

    In case of that column diameter is restricted by the narrow construction space, Concrete filled steel tube column is used. Authors developed new arrangement of bars that the range of longitudinal reinforcement ratio is from 14.8% to 24.7% and the longitudinal reinforcements are reinforced by spiral reinforcement. For the confirmation of the damage form and the deformation performance of the column with new bar arrangement at the earthquake, static reversal cyclic loading test was carried out. The parameters are longitudinal reinforcement ratio, shear span ratio and strength ratio. As the result, the damage form showed different trends due to longitudinal reinforcement ratio, shear span ratio and flexural strength and shear strength ratio. And specimens with the new bar arrangement had a good ductility with rotation angle of the column more than 1/10 and no rapid decline of strength. And, it is possible to evaluate ultimate bending capacity by considering the damage situation at maximum load.

  5. SNAP-TITE Composite Column Reinforcement

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Recent earthquakes throughout the world have demonstrated the vulnerabilities of older reinforced concrete columns to seismic deformation demands. The Snap Tite Composite Column Reinforcement strengthens a concrete column by confining it in an external composite jacket, which prevents the concrete from expanding during seismic activity or prolonged freeze-thaw cycles. The pre-manufactured fiberglass jacket is comprised of glass fibers and corrosion resistant isopolyester resins.

  6. Parametric resonance in concrete beam-columns

    OpenAIRE

    Sharma,Mamta R.; Singh,Arbind K; Benipal,Gurmail S

    2014-01-01

    A dynamic instability, called parametric resonance, is exhibited by undampedelastic beam-columns when under the action of pulsating axial force. The scope of the existing theory of parametric resonance is restricted to physically linear beam-columns undergoing finite lateral displacements. In this Paper, the dynamic behaviour of physically nonlinear elastic cracked concrete beam-columns under pulsating axial force and constant lateral force is investigated. The constitutive equations derived ...

  7. Articles comprising ferritic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Rakowski, James M.

    2016-06-28

    An article of manufacture comprises a ferritic stainless steel that includes a near-surface region depleted of silicon relative to a remainder of the ferritic stainless steel. The article has a reduced tendency to form an electrically resistive silica layer including silicon derived from the steel when the article is subjected to high temperature oxidizing conditions. The ferritic stainless steel is selected from the group comprising AISI Type 430 stainless steel, AISI Type 439 stainless steel, AISI Type 441 stainless steel, AISI Type 444 stainless steel, and E-BRITE.RTM. alloy, also known as UNS 44627 stainless steel. In certain embodiments, the article of manufacture is a fuel cell interconnect for a solid oxide fuel cell.

  8. The Impact of Corrosion on the Mechanical Behavior of Welded Splices of Reinforcing Steel S400 and B500c

    Science.gov (United States)

    Apostolopoulos, Ch. Alk.; Michalopoulos, D.; Dimitrov, L.

    2008-02-01

    The reinforcing steel, used in concrete structures, when corroded causes reduction of the strength properties and especially drastic reduction of ductility. Steel corrosion constitutes an important factor of progressive devaluation of its mechanical properties and serious reduction of the integrity of structures. The problem becomes more evident specifically for structures near coastal areas where salt corrosion is predominant. Reinforced concrete columns and beams are quite often extended by welding new steel reinforcement to the already corroded existing steel. In the present article the impact of corrosion on the mechanical properties of welded splices of reinforcing Steel S400 and B500c is examined. An experimental investigation was conducted and tensile and compressive results are presented for welded precorroded S400 and noncorroded B500c steel splices. The mechanical behavior of welded splices in tension are different in compression and depend strongly on the level of corrosion of the S400 bars.

  9. Effects of Confinement on Interaction Diagrams of Square Reinforced Concrete Columns

    Directory of Open Access Journals (Sweden)

    Recky Tirtajaya

    2009-01-01

    Full Text Available To prevent brittle failure, the design of a structural column in a seismic-resistant building is of important consideration, particularly in terms of confinement. In the recent building code, the need of closely-spaced stirrups in a structural member, such as column becomes compulsory due to the ductility and strength considerations. However, the design is based on the simplified block stress of unconfined concrete, and does not account for the strength gain due to the presence of confinement. To investigate the effects of lateral confinement on the column capacity, an analytical study is carried out. Both the strength gain in concrete core and the loss of strength in the cover are considered in the analytical models to exhibit the remaining strength gain after the mobilization of strength gain in the core concrete to compensate the loss of strength in the concrete cover. There are six key parameters primarily influence the effectiveness of lateral confinement. The most influencing parameter is found to be the spacing of transverse steel. The presence of closely-spaced lateral confinement significantly increases the magnitude of stress-strain curve of concrete. This increase expands the interaction diagram of the column particularly when it is in the compression-controlled region (for lower-story columns when axial load dominates the behavior.

  10. Column: Factors Affecting Data Decay

    Directory of Open Access Journals (Sweden)

    Kevin Fairbanks

    2012-06-01

    Full Text Available In nuclear physics, the phrase decay rate is used to denote the rate that atoms and other particles spontaneously decompose. Uranium-235 famously decays into a variety of daughter isotopes including Thorium and Neptunium, which themselves decay to others. Decay rates are widely observed and wildly different depending on many factors, both internal and external. U-235 has a half-life of 703,800,000 years, for example, while free neutrons have a half-life of 611 seconds and neutrons in an atomic nucleus are stable.We posit that data in computer systems also experiences some kind of statistical decay process and thus also has a discernible decay rate. Like atomic decay, data decay fluctuates wildly. But unlike atomic decay, data decay rates are the result of so many different interplaying processes that we currently do not understand them well enough to come up with quantifiable numbers. Nevertheless, we believe that it is useful to discuss some of the factors that impact the data decay rate, for these factors frequently determine whether useful data about a subject can be recovered by forensic investigation.(see PDF for full column

  11. Repair of corrosion-damaged columns using FRP wraps

    Science.gov (United States)

    Baiyasi, Mohamad Imad

    Many bridge columns in Michigan are damaged by chloride contamination resulting in the corrosion of the steel reinforcement, and swelling and spalling of the concrete and use of the bridges is typically continued. This in itself may not be a serious problem since most columns in Michigan are over-designed and the loss of strength is not a significant issue. However, the lack of any method to minimize or prevent corrosion of the steel results in continued deterioration and unsightly columns. Polymer composite (also known as fiber-reinforced polymer or FRP) jackets offer a possible remedy to this problem. They offer a rapid repair technique with the potential to enhance the longterm durability and compression strength of damaged columns due to the confinement that is provided when fibers are oriented in the hoop direction. Fibers oriented in the vertical direction can enhance the bending strength. Experiments were conducted to assess the effects of using FRP wraps with fibers oriented in the hoop direction for rehabilitating corrosion-damaged columns. Issues that were explored are: (1) effect of freeze-thaw and wet-dry cycles on the properties of FRP panels; (2) freeze-thaw durability of concrete square and cylindrical specimens wrapped with glass and carbon FRP and subjected to an internal expansive force; and (3) effect of wrapping on the rate of corrosion in an accelerated corrosion test. The results of the freeze-thaw experiment indicate that freeze-thaw cycles have no statistically significant effect on the compressive strength of glass and carbon wrapped specimens. For round specimens, glass and carbon wraps increased the strength by a factor of about 2.3 and 2.6, respectively. For square specimens, glass and carbon wraps increased the strength by a factor of 1.4--1.5. Freeze-thaw conditioning generally reduced the longitudinal failure strain of wrapped specimens. The square wrapped specimens had lower compressive strength compared to the round specimens, even

  12. Clean steels for fusion

    Energy Technology Data Exchange (ETDEWEB)

    Gelles, D.S.

    1995-03-01

    Fusion energy production has an inherent advantage over fission: a fuel supply with reduced long term radioactivity. One of the leading candidate materials for structural applications in a fusion reactor is a tungsten stabilized 9% chromium Martensitic steel. This alloy class is being considered because it offers the opportunity to maintain that advantage in the reactor structure as well as provide good high temperature strength and radiation induced swelling and embrittlement resistance. However, calculations indicate that to obtain acceptable radioactivity levels within 500 years after service, clean steel will be required because the niobium impurity levels must be kept below about 2 appm and nickel, molybdenum, nitrogen, copper, and aluminum must be intentionally restricted. International efforts are addressing the problems of clean steel production. Recently, a 5,000 kg heat was vacuum induction melted in Japan using high purity commercial raw materials giving niobium levels less than 0.7 appm. This paper reviews the need for reduced long term radioactivity, defines the advantageous properties of the tungsten stabilized Martensitic steel class, and describes the international efforts to produce acceptable clean steels.

  13. Rasch models with exchangeable rows and columns

    DEFF Research Database (Denmark)

    Lauritzen, Steffen Lilholt

    The article studies distributions of doubly infinite binary matrices with exchangeable rows and columns which satify the further property that the probability of any $m \\times n$ submatrix is a function of the row- and column sums of that matrix. We show that any such distribution is a (unique...... of existence of measures with given marginals....

  14. Circulation in gas-slurry column reactors

    Energy Technology Data Exchange (ETDEWEB)

    Clark, N.; Kuhlman, J.; Celik, I.; Gross, R.; Nebiolo, E.; Wang, Yi-Zun.

    1990-08-15

    Circulation in bubble columns, such as those used in fischer-tropsch synthesis, detracts from their performance in that gas is carried on average more rapidly through the column, and the residence time distribution of the gas in the column is widened. Both of these factors influence mass-transfer operations in bubble columns. Circulation prediction and measurement has been undertaken using probes, one-dimensional models, laser Doppler velocimetry, and numerical modeling. Local void fraction was measured using resistance probes and a newly developed approach to determining air/water threshold voltage for the probe. A tall column of eight inch diameter was constructed of Plexiglas and the distributor plate was manufactured to distribute air evenly through the base of the column. Data were gathered throughout the volume at three different gas throughputs. Bubble velocities proved difficult to measure using twin probes with cross-correlation because of radial bubble movement. A series of three-dimensional mean and RMS bubble and liquid velocity measurements were also obtained for a turbulent flow in a laboratory model of a bubble column. These measurements have been made using a three-component laser Doppler velocimeter (LDV), to determine velocity distributions non-intrusively. Finally, the gas-liquid flow inside a vertically situated circular isothermal column reactor was simulated numerically. 74 refs., 170 figs., 5 tabs.

  15. Influence of tray hydraulics on tray column

    NARCIS (Netherlands)

    Betlem, Bernardus H.L.; Rijnsdorp, J.E.; Rijnsdorp, J.E.; Azink, R.F.

    1998-01-01

    To column control, in contrast to column design, tray hold-up and dependencies of tray hold-up on the operating conditions play an important role. The essence of this article is the development of an improved model of tray hydraulics over a broad operating range and its experimental validation by

  16. Effect of reinforcing steel debonding on RC frame performance in resisting progressive collapse

    Directory of Open Access Journals (Sweden)

    Waleed Mohamed Elsayed

    2016-12-01

    Full Text Available This paper presents the experimental program performed to study the effect of reinforcing steel debonding on progressive collapse resistance of moment resisting frame designed and detailed in accordance with the Egyptian code provisions for seismic design. Half-scale specimens of the first story were extracted from the frame structure prototype. Each specimen represented a two-bay beam resulting from the removal of middle supporting column of the lower floor. In all specimens, the exterior two short columns were restrained against horizontal and vertical displacements and a monotonic vertical load was applied on the middle column stub to simulate the vertical load of the upper stories. Gradually increasing vertical load at the location of the removed column is continuously applied and increased up to failure. The cracking patterns, strains and the deformations at selected locations of reinforcing steel and concrete are recorded for further analysis. Different debonded reinforcement ratios, places and length are examined in this study to evaluate its effect on the collapse resistance performance of the frame. The effect of debonding on the distribution of reinforcing steel strain is evaluated. The nonlinear response of the frame to the removal of the column is evaluated and the amount of energy absorbed during the course of deformation is calculated.

  17. Predicting Nonlinear Behavior and Stress-Strain Relationship of Rectangular Confined Reinforced Concrete Columns with ANSYS

    Directory of Open Access Journals (Sweden)

    A. Tata

    2009-01-01

    Full Text Available This paper presents a nonlinear finite element modeling and analysis of rectangular normal-strength reinforced concrete columns confined with transverse steel under axial compressive loading. In this study, the columns were modeled as discrete elements using ANSYS nonlinear finite element software. Concrete was modeled with 8-noded SOLID65 elements that can translate either in the x-, y-, or z-axis directions from ANSYS element library. Longitudinal and transverse steels were modeled as discrete elements using 3D-LINK8 bar elements available in the ANSYS element library. The nonlinear constitutive law of each material was also implemented in the model. The results indicate that the stress-strain relationships obtained from the analytical model using ANSYS are in good agreement with the experimental data. This has been confirmed with the insignificant difference between the analytical and experimental, i.e. 5.65 and 2.80 percent for the peak stress and the strain at the peak stress, respectively. The comparison shows that the ANSYS nonlinear finite element program is capable of modeling and predicting the actual nonlinear behavior of confined concrete column under axial loading. The actual stress-strain relationship, the strength gain and ductility improvement have also been confirmed to be satisfactorily.

  18. A rapid column technique for trapping and collecting of volatile fungal hydrocarbons and hydrocarbon derivatives.

    Science.gov (United States)

    Booth, Eric; Strobel, Gary; Knighton, Berk; Sears, Joe; Geary, Brad; Avci, Recep

    2011-10-01

    A custom-made stainless steel column was designed to contain various materials that would trap the hydrocarbons and hydrocarbon derivatives during the processes of fungal fermentation ultimately yielding preparative amounts of volatile organic substances (VOCs). Trapping materials tested in the column were Carbotrap materials A and B (Supelco) as well as bentonite-shale from the oil bearing areas of Eastern Montana, the former allowed for the effective and efficient trapping of VOCs from purged cultures of Hypoxylon sp. Trapping efficiencies of various materials were measured by both gravimetric as well as proton transfer reaction mass spectroscopy with the Carbotraps A and B being 99% efficient when tested with known amounts of 1,8-cineole. Trapped fungal VOCs could effectively be removed and recovered via controlled heating of the stainless steel column followed by passage of the gases through a liquid nitrogen trap at a recovery rate of ca 65-70%. This method provides for the recovery of mg quantities of compounds normally present in the gas phase that may be needed for spectroscopy, bioassays and further separation and analysis and may have wide applicability for many other biological systems involving VOCs. Other available Carbotraps could be used for other applications.

  19. Thermochemical surface engineering of steels

    DEFF Research Database (Denmark)

    Thermochemical Surface Engineering of Steels provides a comprehensive scientific overview of the principles and different techniques involved in thermochemical surface engineering, including thermodynamics, kinetics principles, process technologies and techniques for enhanced performance of steels...

  20. Continuous steel production and apparatus

    Science.gov (United States)

    Peaslee, Kent D.; Peter, Jorg J.; Robertson, David G. C.; Thomas, Brian G.; Zhang, Lifeng

    2009-11-17

    A process for continuous refining of steel via multiple distinct reaction vessels for melting, oxidation, reduction, and refining for delivery of steel continuously to, for example, a tundish of a continuous caster system, and associated apparatus.

  1. Prediction of Axial Capacity of Concrete-Filled Square Steel Tubes Using Neural Networks

    Institute of Scientific and Technical Information of China (English)

    Zhu Meichun; Wang Qingxiang; Feng Xiufeng

    2005-01-01

    The application of artificial neural network to predict the ultimate beating capacity of CFST ( concrete-filled square steel tubes)short columns under axial loading is explored. Input parameters consiste of concrete compressive strength, yield strength of steel tube, confinement index, sectional dimension and width-to-thickness ratio. The ultimate bearing capacity is the only output parameter. A multilayer feedforward neural network is used to describe the nonlinear relationships between the input and output variables.Fifty-five experimental data of CFST short columns under axial loading are used to train and test the neural network. A comparison between the neural network model and three parameter models shows that the neural network model possesses good accuracy and could be a practical method for predicting the ultimate strength of axially loaded CFST short columns.

  2. Fatigue damage of steel components

    DEFF Research Database (Denmark)

    Fæster, Søren; Zhang, Xiaodan; Huang, Xiaoxu

    2014-01-01

    Railway rails and the inner ring in roller bearings in wind turbines are both experiencing steel-to-steel contact in small areas with huge loads resulting in extremely high stresses in the base materials......Railway rails and the inner ring in roller bearings in wind turbines are both experiencing steel-to-steel contact in small areas with huge loads resulting in extremely high stresses in the base materials...

  3. Optimization of the place of the plastic hinges by steel braces at RC buildings

    Science.gov (United States)

    Hatami, Farzad; Ragheb, Mohammad; Namazi, Meysam

    2012-12-01

    Usage of steel braces has become a solution not only for retrofitting of RC structures but as a method in designing of concrete frames in recent years. Although X-braced RC frames have been number of successful studies, but eccentric braced RC frames have not been studied seriously. Maybe it's because of the non ductile behaviour of concrete beams. In this article, a numerical study was conducted to evaluate performance of concrete frames, braced with eccentric steel brace with a vertical steel shear link. Vertical steel shear link eliminated shortcomings of non ductile concrete beam. Therefore 4, 8 and 12 storey concrete frames were designed and subjected to a push over analysis. Life safety level was chose to evaluate the frames and hinges performance. Results were compared with the same frames designed with X braces and moment resisting frame. Results indicated that steel braces shift the place of plastic hinges to be formed on the bracing members instead of columns and beams. Furthermore steel braces delayed the process of formation of first plastic hinge and column failure mechanism.

  4. 3-D nonlinear dynamic progressive collapse analysis of multi-storey steel composite frame buildings—Parametric study

    OpenAIRE

    Fu, F.

    2010-01-01

    A 3-dimensional finite element model built by the author was used in this paper to analyze the progressive collapse of a multi-storey steel composite frame building. The proposed model can represent the global 3-D behavior of the multi-storey building under the sudden column removal scenarios. Based on this model, parametric studies were carried out to investigate the structural behavior with variations in: strength of structural steel, strength of concrete and reinforcement mesh size. Throug...

  5. Bearing Capacities of Different-Diameter Concrete-Filled Steel Tubes under Axial Compression

    Directory of Open Access Journals (Sweden)

    Wenjing Wang

    2016-01-01

    Full Text Available The bearing capacities of concrete-filled steel tubes are normally derived through experiments with small-scale specimens, but it is uncertain whether such derivations are appropriate for the much larger components used in practical engineering. This study therefore investigates the effect of different diameters (219, 426, 630, and 820 mm on the axial compression of short concrete columns in steel (Q235 tubes. It is found that the peak nominal stress decreases with increasing specimen size and that the axial bearing capacity is determined by three separate components: the cylinder compressive strength of the concrete, the improvement in strength due to the confining effect of the steel tube, and the longitudinal strength of the steel tube. At peak load, increases in the specimen diameter reduce the hoop stresses in the steel tube, thereby reducing the strengthening effect of confinement. Vertical stress in the steel tube is increased with diameter; therefore, the axial bearing capacity of the steel tube is directly related to the specimen size. Size effect coefficients for these three aspects of bearing capacity are defined and used to develop a size-dependent model for predicting the axial bearing capacity of large, concrete-filled steel tubes. The model is then validated against experimental data.

  6. A-3 steel work completed

    Science.gov (United States)

    2009-01-01

    Stennis Space Center engineers celebrated a key milestone in construction of the A-3 Test Stand on April 9 - completion of structural steel work. Workers with Lafayette (La.) Steel Erector Inc. placed the last structural steel beam atop the stand during a noon ceremony attended by more than 100 workers and guests.

  7. Joints in steel buildings

    Directory of Open Access Journals (Sweden)

    Gabriel F. Valencia Clement

    2010-04-01

    Full Text Available Masonry and steel components used in constructing buildings are in a constant state of motion. Volumetric changes are produced by temperature variation and deformation resulting from static or dynamic loading and in some materials, such as masonry, due to moisture content. This article addresses means of determining when expansion and seismic joints are required and how to proportion and design appropriate joints, specifically in steel buildings. It does not cover the study of expansion joints in concrete structures, in masonry construction or in non-structural (architectural elements.

  8. Highly efficient capillary columns packed with superficially porous particles via sequential column packing.

    Science.gov (United States)

    Treadway, James W; Wyndham, Kevin D; Jorgenson, James W

    2015-11-27

    Highly efficient capillary columns packed with superficially porous particles were created for use in ultrahigh pressure liquid chromatography. Superficially porous particles around 1.5μm in diameter were packed into fused silica capillary columns with 30, 50, and 75μm internal diameters. To create the columns, several capillary columns were serially packed from the same slurry, with packing progress plots being generated to follow the packing of each column. Characterization of these columns using hydroquinone yielded calculated minimum reduced plate heights as low as 1.24 for the most efficient 30μm internal diameter column, corresponding to over 500,000plates/m. At least one highly efficient column (minimum reduced plate height less than 2) was created for all three of the investigated column inner diameters, with the smallest diameter columns having the highest efficiency. This study proves that highly efficient capillary columns can be created using superficially porous particles and shows the efficiency potential of these particles.

  9. Microbial-Influenced Corrosion of Corten Steel Compared with Carbon Steel and Stainless Steel in Oily Wastewater by Pseudomonas aeruginosa

    Science.gov (United States)

    Mansouri, Hamidreza; Alavi, Seyed Abolhasan; Fotovat, Meysam

    2015-07-01

    The microbial corrosion behavior of three important steels (carbon steel, stainless steel, and Corten steel) was investigated in semi petroleum medium. This work was done in modified nutrient broth (2 g nutrient broth in 1 L oily wastewater) in the presence of Pseudomonas aeruginosa and mixed culture (as a biotic media) and an abiotic medium for 2 weeks. The behavior of corrosion was analyzed by spectrophotometric and electrochemical methods and at the end was confirmed by scanning electron microscopy. The results show that the degree of corrosion of Corten steel in mixed culture, unlike carbon steel and stainless steel, is less than P. aeruginosa inoculated medium because some bacteria affect Corten steel less than other steels. According to the experiments, carbon steel had less resistance than Corten steel and stainless steel. Furthermore, biofilm inhibits separated particles of those steels to spread to the medium; in other words, particles get trapped between biofilm and steel.

  10. Dynamic Effects of Diabatization in Distillation Columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

    2012-01-01

    The dynamic eects of diabatization in distillation columns are investigated in simulation with primary focus on the heat-integrated distillation column (HIDiC). A generic, dynamic, rst-principle model has been formulated, which is exible to describe various diabatic distillation congurations....... Dynamic Relative Gain Array and Singular Value Analysis have been applied in a comparative study of a conventional distillation column and a HIDiC. The study showed increased input-output coupling due to diabatization. Feasible SISO control structures for the HIDiC were also found. Control...

  11. Dynamic effects of diabatization in distillation columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

    2013-01-01

    The dynamic effects of diabatization in distillation columns are investigated in simulation emphasizing the heat-integrated distillation column (HIDiC). A generic, dynamic, first-principle model has been formulated, which is flexible enough to describe various diabatic distillation configurations....... Dynamic Relative Gain Array and Singular Value Analysis have been applied in a comparative study of a conventional distillation column and a HIDiC. The study showed increased input-output coupling due to diabatization. Feasible SISO control structures for the HIDiC were also found and control...

  12. 29 CFR 1926.756 - Beams and columns.

    Science.gov (United States)

    2010-07-01

    ... (.46 m) from the extreme outer face of the column in each direction at the top of the column shaft. (e) Perimeter columns. Perimeter columns shall not be erected unless: (1) The perimeter columns extend a minimum of 48 inches (1.2 m) above the finished floor to permit installation of perimeter safety cables prior...

  13. Precipitates in electrical steels

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, Keith [Development and Market Research, Cogent Power Limited, Corporation Road, Newport, South Wales NP19 OXT (United Kingdom)], E-mail: keith.jenkins@cogent-power.com; Lindenmo, Magnus [Development and Market Research, Cogent Power Limited, Corporation Road, Newport, South Wales NP19 OXT (United Kingdom)

    2008-10-15

    Precipitates heavily influence the magnetic properties of electrical steels, either as a key controlled requirement as part of the manufacturing process or as an unwanted harmful residual in the final product. In this current work copper-manganese sulphides precipitates are the primary inhibitor species in the conventional grain-oriented (CGO) steels examined and grain boundary pinning is effective at a mean precipitate size of 30-70 nm. The growth of CuMnS has been studied and the results show that a precipitate size above {approx}100 nm allows the onset of secondary recrystallisation in the heating conditions applied. The effect of precipitates on the magnetic properties of both grain-oriented and non-oriented steels in their final product form is then examined. Examples of grain-oriented material still containing large numbers of precipitates clearly show the detrimental effects with increases in total power loss of 40% or more. Loss deterioration by about 20% is also seen in samples of high silicon non-oriented material in which titanium carbo-nitride precipitates have been observed. In this case the precipitates are believed to have formed during cooling after final annealing. Finally a grain-oriented steel with a large number of very small precipitates, which do not seem to have any harmful effect on the magnetic properties, is demonstrated.

  14. Japan steel mill perspective

    Energy Technology Data Exchange (ETDEWEB)

    Murase, K. [Kobe Steel Ltd., Tokyo (Japan)

    2004-07-01

    The international and Japan's steel industry, the coking coal market, and Japan's expectations from Canada's coal industry are discussed. Japan's steel mills are operating at full capacity. Crude steel production for the first half of 2004 was 55.8 million tons. The steel mills are profitable, but costs are high, and there are difficulties with procuring raw materials. Japan is trying to enhance the quality of coke, in order to achieve higher productivity in the production of pig iron. Economic growth is rising disproportionately in the BRICs (Brazil, Russia, India, and China), with a large increase in coking coal demand from China. On the supply side, there are several projects underway in Australia and Canada to increase production. These include new developments by Elk Valley Coal Corporation, Grande Cache Coal, Western Canadian Coal, and Northern Energy and Mining in Canada. The Elga Mine in the far eastern part of Russia is under development. But the market is expected to remain tight for some time. Japan envisions Canadian coal producers will provide a stable coal supply, expansion of production and infrastructure capabilities, and stabilization of price. 16 slides/overheads are included.

  15. Column IIIA metal film deposition by dissociative photoionization of metal halide vapors

    Science.gov (United States)

    Geohegan, D. B.; Eden, J. G.

    1984-11-01

    Films of column IIIA metals (In, Al, and Tl) have been deposited on several different substrates (stainless steel, nickel, copper, and silver) by dissociatively photoionizing the corresponding metal iodide in a uniform electric field. Thin (≲0.2 μm) indium films have been grown on nickel by photoionizing indium monoiodide (InI) vapor with an argon fluoride (ArF) excimer laser at 193 nm. A similar process has resulted in thallium films produced from thallium iodide (TlI) vapor with a high pressure xenon lamp.

  16. Validation of stormwater biofilters using in-situ columns.

    Science.gov (United States)

    Zhang, Kefeng; Valognes, Valentin; Page, Declan; Deletic, Ana; McCarthy, David

    2016-02-15

    Stormwater harvesting biofilters need to be validated if the treatment is to be relied upon. Currently, full-scale challenge tests (FCTs), performed in the field, are required for their validation. This is impractical for stormwater biofilters because of their size and flow capacity. Hence, for these natural treatment systems, new tools are required as alternatives to FCT. This study describes a novel in-situ method that consists of a thin stainless steel column which can be inserted into constructed biofilters in a non-destructive manner. The in-situ columns (ISCs) were tested using a controlled field-scale biofilter where FCT is possible. Fluorescein was initially used for testing through a series of continuous applications. The results from the ISC were compared to FCT conducted under similar operational conditions. Excellent agreement was obtained for the series of continuous fluorescein experiments, demonstrating that the ISC was able to reproduce FCT results even after extended drying periods (Nash-Sutcliffe coefficient between the two data sets was 0.83-0.88), with similar plateaus, flush peaks, slopes and treatment capacities. The ISCs were then tested for three herbicides: atrazine, simazine and prometryn. While the ISC herbicide data and the FCT data typically matched well, some differences observed were linked to the different climatic conditions during the ISC (winter) and FCT tests (summer). The work showed that ISC is a promising tool to study the field performance of biofilters and could be a potential alternative to full scale challenge tests for validation of stormwater biofilters when taking into account the same inherent boundary conditions.

  17. Electroosmotic Driving Liquid Using Nanosilica Packed Column

    Institute of Scientific and Technical Information of China (English)

    Ling Xin CHEN; Guo An LUO; Tao WEN

    2005-01-01

    The electroosmotic pump (EOP) using nanosilica particles packed-bed column was experimentally studied. The relationship between flowrate, pressure and applied voltage of the pump, and pressure-flowrate (P-Q) characteristic were investigated.

  18. Early development of the vertebral column.

    Science.gov (United States)

    Scaal, Martin

    2016-01-01

    The segmental organization of the vertebrate body is most obviously visible in the vertebral column, which consists of a series of vertebral bones and interconnecting joints and ligaments. During embryogenesis, the vertebral column derives from the somites, which are the primary segments of the embryonic paraxial mesoderm. Anatomical, cellular and molecular aspects of vertebral column development have been of interest to developmental biologists for more than 150 years. This review briefly summarizes the present knowledge on early steps of vertebral column development in amniotes, starting from sclerotome formation and leading to the establishment of the anatomical bauplan of the spine composed of vertebral bodies, vertebral arches, intervertebral discs and ribs, and their specific axial identities along the body axis.

  19. Modeling Tropical Precipitation in a Single Column.

    Science.gov (United States)

    Sobel, Adam H.; Bretherton, Christopher S.

    2000-12-01

    A modified formulation of the traditional single column model for representing a limited area near the equator is proposed. This formulation can also be considered a two-column model in the limit as the area represented by one of the columns becomes very large compared to the other. Only a single column is explicitly modeled, but its free tropospheric temperature, rather than its mean vertical velocity, is prescribed. This allows the precipitation and vertical velocity to be true prognostic variables, as in prior analytical theories of tropical precipitation. Two models developed by other authors are modified according to the proposed formulation. The first is the intermediate atmospheric model of J. D. Neelin and N. Zeng, but with the horizontal connections between columns broken, rendering it a set of disconnected column models. The second is the column model of N. O. Rennó, K. A. Emanuel, and P. H. Stone. In the first model, the set of disconnected column models is run with a fixed temperature that is uniform in the Tropics, and insolation, SST, and surface wind speed taken from a control run of the original model. The column models produce a climatological precipitation field that is grossly similar to that of the control run, despite that the circulation implied by the column models is not required to conserve mass. The addition of horizontal moisture advection by the wind from the control run substantially improves the simulation in dry regions. In the second model the sensitivity of the modeled steady-state precipitation and relative humidity to varying SST and wind speed is examined. The transition from shallow to deep convection is simulated in a `Lagrangian' calculation in which the column model is subjected to an SST that increases in time. In this simulation, the onset of deep convection is delayed to a higher SST than in the steady-state case, due to the effect of horizontal moisture advection (viewed in a Lagrangian reference frame). In both of the

  20. Special steel production on common carbon steel production line

    Science.gov (United States)

    Pi, Huachun; Han, Jingtao; Hu, Haiping; Bian, Ruisheng; Kang, Jianjun; Xu, Manlin

    2004-06-01

    The equipment and technology of small bar tandem rolling line of Shijiazhuang Iron & Steel Co. in China has reached the 90's international advanced level in the 20th century, but products on the line are mostly of common carbon steel. Currently there are few steel plants in China to produce 45 steel bars for cold drawing, which is a kind of shortage product. Development of 45 steel for cold drawing has a wide market outlook in China. In this paper, continuous cooling transformation (CCT) curve of 45 steel for cold drawing used for rolling was set out first. According to the CCT curve, we determined some key temperature points such as Ac3 temperature and Ac1 temperature during the cooling procedure and discussed the precipitation microstructure at different cooling rate. Then by studying thermal treatment process of 45 steel bars for cold drawing, the influence of cooling time on microstructure was analyzed and the optimum cooling speed has been found. All results concluded from the above studies are the basis of regulating controlled cooling process of 45 steel bars for cold drawing. Finally, the feasible production process of 45 steel bars for cold drawing on common carbon steel production line combined with the field condition was recommended.

  1. Nonlinear control of high purity distillation columns

    OpenAIRE

    Groebel, Markus; Allgöwer, Frank; Storz, Markus; Gilles, Ernst Dieter

    1994-01-01

    Two simple models of distillation columns are studied to investigate their suitability for the practical use with exact I/O-linearization. An extension of exact I/O-linearization, the asymptotically exact I/O-linearization is applied to the control of a high purity distillation column, using one of these models to derive the static state feedback law. Simulation studies demonstrate the advantage of asymptotically exact I/O-linearization versus classical exact I/O-linearization techniques. Exp...

  2. Fuzzy Based composition Control of Distillation Column

    Directory of Open Access Journals (Sweden)

    Guru.R

    2013-04-01

    Full Text Available This paper proposed a control scheme based on fuzzy logic for a methanol - water system of bubble cap distillation column. Fuzzy rule base and Inference System of fuzzy (FIS is planned to regulatethe reflux ratio (manipulated variable to obtain the preferred product composition (methanol for a distillation column. Comparisons are made with conventional controller and the results confirmed the potentials of the proposed strategy of fuzzy control.

  3. The handedness of historiated spiral columns.

    Science.gov (United States)

    Couzin, Robert

    2016-11-17

    Trajan's Column in Rome (AD 113) was the model for a modest number of other spiral columns decorated with figural, narrative imagery from antiquity to the present day. Most of these wind upwards to the right, often with a congruent spiral staircase within. A brief introductory consideration of antique screw direction in mechanical devices and fluted columns suggests that the former may have been affected by the handedness of designers and the latter by a preference for symmetry. However, for the historiated columns that are the main focus of this article, the determining factor was likely script direction. The manner in which this operated is considered, as well as competing mechanisms that might explain exceptions. A related phenomenon is the reversal of the spiral in a non-trivial number of reproductions of the antique columns, from Roman coinage to Renaissance and baroque drawings and engravings. Finally, the consistent inattention in academic literature to the spiral direction of historiated columns and the repeated publication of erroneous earlier reproductions warrants further consideration.

  4. Gas Chromatograph Method Optimization Trade Study for RESOLVE: 20-meter Column v. 8-meter Column

    Science.gov (United States)

    Huz, Kateryna

    2014-01-01

    RESOLVE is the payload on a Class D mission, Resource Prospector, which will prospect for water and other volatile resources at a lunar pole. The RESOLVE payload's primary scientific purpose includes determining the presence of water on the moon in the lunar regolith. In order to detect the water, a gas chromatograph (GC) will be used in conjunction with a mass spectrometer (MS). The goal of the experiment was to compare two GC column lengths and recommend which would be best for RESOLVE's purposes. Throughout the experiment, an Inficon Fusion GC and an Inficon Micro GC 3000 were used. The Fusion had a 20m long column with 0.25mm internal diameter (Id). The Micro GC 3000 had an 8m long column with a 0.32mm Id. By varying the column temperature and column pressure while holding all other parameters constant, the ideal conditions for testing with each column length in their individual instrument configurations were determined. The criteria used for determining the optimal method parameters included (in no particular order) (1) quickest run time, (2) peak sharpness, and (3) peak separation. After testing numerous combinations of temperature and pressure, the parameters for each column length that resulted in the most optimal data given my three criteria were selected. The ideal temperature and pressure for the 20m column were 95 C and 50psig. At this temperature and pressure, the peaks were separated and the retention times were shorter compared to other combinations. The Inficon Micro GC 3000 operated better at lower temperature mainly due to the shorter 8m column. The optimal column temperature and pressure were 70 C and 30psig. The Inficon Micro GC 3000 8m column had worse separation than the Inficon Fusion 20m column, but was able to separate water within a shorter run time. Therefore, the most significant tradeoff between the two column lengths was peak separation of the sample versus run time. After performing several tests, it was concluded that better

  5. ADVANCED DIAGNOSTIC TECHNIQUES FOR THREE-PHASE SLURRY BUBBLE COLUMN REACTORS (SBCR)

    Energy Technology Data Exchange (ETDEWEB)

    M.H. Al-Dahhan; M.P. Dudukovic; L.S. Fan

    2001-07-25

    This report summarizes the accomplishment made during the second year of this cooperative research effort between Washington University, Ohio State University and Air Products and Chemicals. The technical difficulties that were encountered in implementing Computer Automated Radioactive Particle Tracking (CARPT) in high pressure SBCR have been successfully resolved. New strategies for data acquisition and calibration procedure have been implemented. These have been performed as a part of other projects supported by Industrial Consortium and DOE via contract DE-2295PC95051 which are executed in parallel with this grant. CARPT and Computed Tomography (CT) experiments have been performed using air-water-glass beads in 6 inch high pressure stainless steel slurry bubble column reactor at selected conditions. Data processing of this work is in progress. The overall gas holdup and the hydrodynamic parameters are measured by Laser Doppler Anemometry (LDA) in 2 inch slurry bubble column using Norpar 15 that mimic at room temperature the Fischer Tropsch wax at FT reaction conditions of high pressure and temperature. To improve the design and scale-up of bubble column, new correlations have been developed to predict the radial gas holdup and the time averaged axial liquid recirculation velocity profiles in bubble columns.

  6. Behavior of Reinforced Hybrid Concrete Corbel-Column Connection with Vertical Construction Joint

    Directory of Open Access Journals (Sweden)

    Ammar Yasir Ali

    2017-03-01

    Full Text Available In this paper, shear behavior of reinforced hybrid concrete connection of corbel-column is experimentally investigated. Nine homogenous and hybrid concrete corbel-column connections subjected to vertical applied loads were constructed and tested within two test groups (A, B. The experimental program included the effect of several variables such as type of hybrid concrete;high strength concrete (HSC or steel fiber reinforced concrete (SFRC, monolithic casting of hybrid concrete connection, and presence of construction joint at the interface of corbel-column. Experimental results showed significant effects of concrete hybridization on the structural behavior of connection specimens such as: ultimate strength, cracking loads, cracking patterns, and failure modes. Hybridization process in group (A included hybrid connection of corbel-column with HSC or SFRC corbel instated of NSC. This process led to increase the capacity of connection by (26%, 38% and shear cracking loads by (20%, 120% respectively. Moreover, connections of hybrid concrete corbels cast monolithically improved the shear capacity of corbels by (19%, 42% for HSC or SFRC respectively. In group (B, presence of construction joint at connection region reduced the shear capacity of connectionsby (10% to 22% and cracking loads by (23%-62% compared with connections cast monolithically.

  7. Assessment of Residual Strength Based on Estimated Temperature of Post-Heated RC Columns

    Directory of Open Access Journals (Sweden)

    Muhammad Yaqub

    2013-01-01

    Full Text Available The experience shows that fire-damaged concrete structures both technically and economically can be reinstated after fire due to high fire resistance and high residual strength. The residual strength of fire-damaged concrete structural member depends on the peak temperature reached during fire, fire duration and the distribution of temperature within the structural member. The assessment of the residual strength of post-heated concrete structural members in a professional way is a prime factor to take a decision about the reinstatement or demolition of fire-damaged structure. This paper provides an easy and efficient approach to predict the residual strength of reinforced concrete columns based on the estimated temperature which may have occurred within the concrete cross-section during a fire. A finite element model was developed to evaluate the distribution of temperature within the cross-section of the reinforced concrete columns. Twelve reinforced concrete square columns were heated experimentally up to 500°C at 150°C/hour. A comparison of the experimental temperature values of the tested columns was made with the model results. A good agreement was found between the experimental and the finite model results. Based on the temperature distribution obtained from the finite element model, the residual strength of concrete and reinforcement could be evaluated by using the relationships for concrete, steel and temperature proposed by various researchers.

  8. Behaviour of Reinforced Concrete Columns of Various Cross-Sections Subjected to Fire

    Science.gov (United States)

    Balaji, Aneesha; Muhamed Luquman, K.; Nagarajan, Praveen; Madhavan Pillai, T. M.

    2016-09-01

    Fire resistance is one of the crucial design regulations which are now mandatory in most of the design codes. Therefore, a thorough knowledge of behaviour of structures exposed to fire is required in this aspect. Columns are the most vulnerable structural member to fire as it can be exposed to fire from all sides. However, the data available for fire resistant design for columns are limited. Hence the present work is focused on the effect of cross-sectional shape of column in fire resistance design. The various cross-sections considered are Square, Ell (L), Tee (T), and Plus (`+') shape. Also the effect of size and shape and distribution of steel reinforcement on fire resistance of columns is studied. As the procedure for determining fire resistance is not mentioned in Indian Standard code IS 456 (2000), the simplified method (500 °C isotherm method) recommended in EN 1992-1-2:2004 (E) (Eurocode 2) is adopted. The temperature profiles for various cross-sections are developed using finite element method and these profiles are used to predict fire resistance capability of compression members. The fire resistance based on both numerical and code based methods are evaluated and compared for various types of cross-section.

  9. Studies and research concerning BNFP pilot-scale pulsed columns: column profile and holdup studies

    Energy Technology Data Exchange (ETDEWEB)

    Cermak, A. F.

    1980-11-01

    Experimental studies were conducted on pilot-scaled pulsed columns for the purpose of obtaining data for verification of contactor computer programs. This work is in support of safeguards programs related to determination of near real-time inventories in pulsed columns. Holdup tests were performed resulting in the derivation of an empirical equation for estimation of the dispersed phase holdup in a column. Uranium solvent extraction mass-transfer tests were conducted in which all four process cycles were simulated under coprocessing flowsheet conditions. Extensive data were obtained during these tests on uranium profiles and inventories within the columns. Transient profile data were also determined between selected runs under the tested operating conditions. No concentration peaks could be observed during the transient period. Based on the extensive inventory data taken, empirical equations were developed for relating uranium inventory in a column to the test parameters. These equations were found useful for predicting and estimating the column inventory under the known run conditions.

  10. Calculation and design of steel bearing structure for wind turbine

    Directory of Open Access Journals (Sweden)

    Bešević Miroslav

    2014-01-01

    Full Text Available Wind represents directed movement of the air and is caused by differences in atmospheric pressure which are caused by uneven heating of air masses. Global and local winds can be distinguished. Global winds have high altitude, while local winds occur in the ground layer of the atmosphere. Given that the global wings have high altitude they cannot be used as propellant for wind generators, but they should be known for their effects on the winds in the lower atmosphere. Modern wind turbines are made with a horizontal axle that has a system for the swiveling axis in the horizontal plane for tracking wind direction changes. They can have different number of blades, but for larger forces three blades are commonly used because they provide the greatest efficiency. Rotor diameter of these turbines depends on the strength and it ranges from 30 m for the power of 300 kW to 115 m for the power of 5 MW. Wind turbines are mounted on vertical steel tower which can be high even more than 100 m. Depending on the diameter of the turbine rotor, column is usually built as steel conical and less often as a steel-frame. This study includes analysis and design of steel tower for wind generator made by manufacturer Vestas, type V112 3MW HH 119 (power 3.2 MW for the construction of wind farm 'Kovačica'.

  11. History of ultrahigh carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Wadsworth, J.; Sherby, O.D.

    1997-06-20

    The history and development of ultrahigh carbon steels (i.e., steels containing between 1 and 2.l percent C and now known as UHCS) are described. The early use of steel compositions containing carbon contents above the eutectoid level is found in ancient weapons from around the world. For example, both Damascus and Japanese sword steels are hypereutectoid steels. Their manufacture and processing is of interest in understanding the role of carbon content in the development of modern steels. Although sporadic examples of UHCS compositions are found in steels examined in the early part of this century, it was not until the mid-1970s that the modern study began. This study had its origin in the development of superplastic behavior in steels and the recognition that increasing the carbon content was of importance in developing that property. The compositions that were optimal for superplasticity involved the development of steels that contained higher carbon contents than conventional modern steels. It was discovered, however, that the room temperature properties of these compositions were of interest in their own right. Following this discovery, a period of intense work began on understanding their manufacture, processing, and properties for both superplastic forming and room temperature applications. The development of superplastic cast irons and iron carbides, as well as those of laminated composites containing UHCS, was an important part of this history.

  12. Fire-induced collapse mechanisms of steel buildings

    DEFF Research Database (Denmark)

    Giuliani, Luisa; Aiuti, Riccardo; Bontempi, Franco

    2013-01-01

    and eigen-stresses induced by a restrained thermal expansion are not considered by current design methods and regulations, but are known to have driven the collapse of several steel and composite structures. In this study, the effect of restrained thermal expansions of steel beams exposed to fire...... therefore be avoided even in case a timely evacuation of the premises is ensured by a proper fire design. In multi-story buildings instead, stiff continuous columns are typically required in order to resist horizontal actions and sustain the weight of the tall structure. As a consequence, the thermal...... significant in case the fire has spread through several floors, occurrence which is not contemplated by current fire design requirements, but that has been observed in most high-rise building fires. The results of the studies show that unfavourable collapse of single-story buildings and progressive collapse...

  13. Structural Decoupling and Disturbance Rejection in a Distillation Column

    DEFF Research Database (Denmark)

    Bahar, Mehrdad; Jantzen, Jan; Commault, C.

    1996-01-01

    Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references.......Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references....

  14. Column Selection for Biomedical Analysis Supported by Column Classification Based on Four Test Parameters.

    Science.gov (United States)

    Plenis, Alina; Rekowska, Natalia; Bączek, Tomasz

    2016-01-21

    This article focuses on correlating the column classification obtained from the method created at the Katholieke Universiteit Leuven (KUL), with the chromatographic resolution attained in biomedical separation. In the KUL system, each column is described with four parameters, which enables estimation of the FKUL value characterising similarity of those parameters to the selected reference stationary phase. Thus, a ranking list based on the FKUL value can be calculated for the chosen reference column, then correlated with the results of the column performance test. In this study, the column performance test was based on analysis of moclobemide and its two metabolites in human plasma by liquid chromatography (LC), using 18 columns. The comparative study was performed using traditional correlation of the FKUL values with the retention parameters of the analytes describing the column performance test. In order to deepen the comparative assessment of both data sets, factor analysis (FA) was also used. The obtained results indicated that the stationary phase classes, closely related according to the KUL method, yielded comparable separation for the target substances. Therefore, the column ranking system based on the FKUL-values could be considered supportive in the choice of the appropriate column for biomedical analysis.

  15. 46 CFR 59.20-1 - Carbon-steel or alloy-steel castings.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Carbon-steel or alloy-steel castings. 59.20-1 Section 59... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Castings § 59.20-1 Carbon-steel or alloy-steel castings. Defects in carbon-steel or alloy-steel castings may be repaired by welding. The...

  16. Column flotation of bitumen at Fort Hills

    Energy Technology Data Exchange (ETDEWEB)

    Lizama, H.M. [Teck Cominco, Vancouver, BC (Canada); Romero, D. [UTS Energy Corp., Calgary, AB (Canada); Armour, M. [Petro-Canada, Calgary, AB (Canada)

    2008-05-15

    Flotation columns are used by mineral processors to separate mineral species. The separation is based on the premise that different mineral particles have different surface hydrophobicities. There are 2 carrier phases, notably air bubbles moving up and aqueous pulp moving down. Hydrophobic particles predominantly adhere to rising air bubbles and form a froth, while hydrophilic particles remain in aqueous suspension and flow down and out the bottom of the column. This paper described a demonstration plant near Fort McMurray where bitumen extraction was tested. The plant included 2 columns for bitumen flotation. Oil sands material was passed through a roll sizer and fed to a countercurrent drum separator, where it was mixed with water at 75 degrees C. Column data from the demonstration plant provided the opportunity to examine the separation behaviour during flotation of bitumen. The bitumen grade was described only in terms of bitumen content and solids content in order to simplify the interpretation of the bitumen flotation data. Bitumen/solids separation in the first column was successful at 50 to 60 degrees C, with feeds having bitumen grades between 1 and 19 per cent, and where the solids had about 60 per cent fines. Bitumen/solids separation did not occur in the second column at 50 to 60 degrees C, with feeds having bitumen grades between 8 and 63 per cent, and where the solids had about 90 per cent fines. The lack of separation was probably due to high solids entrainment in the flotation froth. It was concluded that bitumen column flotation data can be analyzed and interpreted by adopting mineral processing principles. Bitumen/solids separation can be evaluated and predicted by plotting solids recovery as a function of bitumen recovery. 7 refs., 1 tab., 6 figs.

  17. Coated 4340 Steel

    Science.gov (United States)

    2013-08-26

    alternative coatings qualified to MIL-PRE-23377 Class N and an electroplated zinc - nickel alloy passivated with a trivalent chromium solution which is...effect of a non-chromate primer and zinc - nickel plating with non-chromate passivation as alternatives to the chromate primer and cadmium plating with...NAWCADPAX/TR-2013/252 COATED 4340 STEEL by E. U. Lee C. Lei M. Stanley B. Pregger C. Matzdorf 26 August 2013

  18. Ferrium M54 Steel

    Science.gov (United States)

    2015-03-18

    Examination ................................................................................................. 2 Zinc - Nickel Alloy Plating...resistance measurements using scans from 100 mV below to 100mV above at a scan rate of 0.167 mV/s. ZINC - NICKEL ALLOY PLATING The Zn-14% Ni alloy...release; distribution is unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT Bare and Zn-14% Ni alloy coated Ferrium M54 steels were studied to

  19. Fracture Mechanisms in Steel Castings

    Directory of Open Access Journals (Sweden)

    Z. Stradomski

    2013-07-01

    Full Text Available The investigations were inspired with the problem of cracking of steel castings during the production process. A single mechanism of decohesion - the intergranular one - occurs in the case of hot cracking, while a variety of structural factors is decisive for hot cracking initiation, depending on chemical composition of the cast steel. The low-carbon and low-alloyed steel castings crack due to the presence of the type II sulphides, the cause of cracking of the high-carbon tool cast steels is the net of secondary cementite and/or ledeburite precipitated along the boundaries of solidified grains. Also the brittle phosphor and carbide eutectics precipitated in the final stage solidification are responsible for cracking of castings made of Hadfield steel. The examination of mechanical properties at 1050°C revealed low or very low strength of high-carbon cast steels.

  20. PHOSPHORUS REMOVAL USING STEEL SLAG

    Institute of Scientific and Technical Information of China (English)

    Y.Z. Lan; S. Zhang; J.K. Wang; R. W. Smith

    2006-01-01

    Steel slag is a byproduct produced in large amounts in the steel-making process. It is an important resource that can be effectively utilized. An experiment was described in which steel slag was tested as an adsorbent for the removal of phosphorus from waste water. Phosphorus removal depended on the amount of steel slag added, the pH value, the contact time, and the initial concentration. Under laboratory conditions when the added slag was 7.5g/L, the contact time 2h, and the pH value was equivalent to 6.5, over 99% of the phosphorus was removed; the experimental data on steel slag adsorption of phosphorus in the water fitted the Freundlich isotherm model. Steel slag was found to be very effective in adsorbing phosphorus.

  1. Post Column Derivatization Using Reaction Flow High Performance Liquid Chromatography Columns.

    Science.gov (United States)

    Jones, Andrew; Pravadali-Cekic, Sercan; Hua, Stanley; Kocic, Danijela; Camenzuli, Michelle; Dennis, Gary; Shalliker, Andrew

    2016-04-26

    A protocol for the use of reaction flow high performance liquid chromatography columns for methods employing post column derivatization (PCD) is presented. A major difficulty in adapting PCD to modern HPLC systems and columns is the need for large volume reaction coils that enable reagent mixing and then the derivatization reaction to take place. This large post column dead volume leads to band broadening, which results in a loss of observed separation efficiency and indeed detection in sensitivity. In reaction flow post column derivatization (RF-PCD) the derivatization reagent(s) are pumped against the flow of mobile phase into either one or two of the outer ports of the reaction flow column where it is mixed with column effluent inside a frit housed within the column end fitting. This technique allows for more efficient mixing of the column effluent and derivatization reagent(s) meaning that the volume of the reaction loops can be minimized or even eliminated altogether. It has been found that RF-PCD methods perform better than conventional PCD methods in terms of observed separation efficiency and signal to noise ratio. A further advantage of RF-PCD techniques is the ability to monitor effluent coming from the central port in its underivatized state. RF-PCD has currently been trialed on a relatively small range of post column reactions, however, there is currently no reason to suggest that RF-PCD could not be adapted to any existing one or two component (as long as both reagents are added at the same time) post column derivatization reaction.

  2. Mechanics in Steels through Microscopy

    OpenAIRE

    Tirumalasetty, G. K.

    2013-01-01

    The goal of the study consolidated in this thesis is to understand the mechanics in steels using microscopy. In particular, the mechanical response of Transformation Induced Plasticity (TRIP) steels is correlated with their microstructures. Chapter 1 introduces the current state of the art of TRIP steels, highlighting the importance of microstructure - mechanical properties - applications relationships. In Chapter 2 the material properties and material processing are described into more detai...

  3. Output Model of Steel Plant

    Institute of Scientific and Technical Information of China (English)

    ZHANG Long-qiang; TIAN Nai-yuan; ZHANG Jin; XU An-jun

    2008-01-01

    Based on the requirement of compactivity, continuity, and high efficiency, and taking full advantage of cushion capability of flexible parts such as external refining in new generation steel plant, an output model of steel plant was established in terms of matching between BOF and caster. Using this model, the BOF nominal capacity is selected, the caster output and equipment amount are computed, and then the steel plant output is computed.

  4. Robust Matrix Completion with Corrupted Columns

    CERN Document Server

    Chen, Yudong; Caramanis, Constantine; Sanghavi, Sujay

    2011-01-01

    This paper considers the problem of matrix completion, when some number of the columns are arbitrarily corrupted, potentially by a malicious adversary. It is well-known that standard algorithms for matrix completion can return arbitrarily poor results, if even a single column is corrupted. What can be done if a large number, or even a constant fraction of columns are corrupted? In this paper, we study this very problem, and develop an efficient algorithm for its solution. Our results show that with a vanishing fraction of observed entries, it is nevertheless possible to succeed in performing matrix completion, even when the number of corrupted columns grows. When the number of corruptions is as high as a constant fraction of the total number of columns, we show that again exact matrix completion is possible, but in this case our algorithm requires many more -- a constant fraction -- of observations. One direct application comes from robust collaborative filtering. Here, some number of users are so-called mani...

  5. Tough Year Ahead for Steel

    Institute of Scientific and Technical Information of China (English)

    REN WEI

    2006-01-01

    @@ The steel industry, a top beneficiary of the country's sizzling economic growth, is this year likely to see only a meager profit or even report losses, according to a report by the National Development and Reform Commission. Mounting demand for steel in real estate construction and auto making during the past years resulted in an investment craze into the sector, and has caused a glut on the market. Average steel prices fell by a third last year, though domestic steel makers still managed to post a profit of 127.4 billion yuan (US$15.9 billion) on aggregate.

  6. High strength, tough alloy steel

    Science.gov (United States)

    Thomas, Gareth; Rao, Bangaru V. N.

    1979-01-01

    A high strength, tough alloy steel is formed by heating the steel to a temperature in the austenite range (1000.degree.-1100.degree. C.) to form a homogeneous austenite phase and then cooling the steel to form a microstructure of uniformly dispersed dislocated martensite separated by continuous thin boundary films of stabilized retained austenite. The steel includes 0.2-0.35 weight % carbon, at least 1% and preferably 3-4.5% chromium, and at least one other substitutional alloying element, preferably manganese or nickel. The austenite film is stable to subsequent heat treatment as by tempering (below 300.degree. C.) and reforms to a stable film after austenite grain refinement.

  7. Hydrogen Embrittlement of Gun Steel

    Science.gov (United States)

    1987-11-01

    8217s HY80 and HY130 steels were checked for the critical hydrogen concentrations which were determined to be 6 ppm for HY8O steel 8 and 3 ppm for HY130...JOTC FILE COPY AD-A188 972 AD 1 TECHNICAL REPORT ARCCB-TR-87030 HYDROGEN EMBRITTLEMENT OF GUN STEEL F’ GERALD L. SPFNCER DTIC DEC 1 5 1987 NOVEMBER...PtEtIOC COVERED HYDROGEN EMBRITTLEHENT OF GUN STEEL Final OG EOTNME 6. PERFORMINGORO EOTNME 7. A*JTNOR(s) S. CONTRACT OR GRANT NUMBER(&) Gerald L

  8. Improved removal of arsenic from groundwater using pre-corroded steel and iron tailored granular activated carbon.

    Science.gov (United States)

    Zou, J; Cannon, F S; Chen, W; Dempsey, B A

    2010-01-01

    The authors have combined corrosion of steel fittings or perforated sheets with granular activated carbon (GAC) that had been pre-treated with Fe(III)-citrate, to produce an innovative and low-maintenance technique for removing arsenic from groundwater. Removal of arsenic was measured using two GAC column configurations: rapid small scale column tests (RSSCT's) and mini-column tests. Independent variables included pH, pre-corrosion procedure, and idling of the column (i.e. intentionally stopping flow for defined times in order to create reducing conditions). Use of corroded steel plus pre-treated GAC removed arsenic to below 10 microg/L for up to 248,000 bed volumes (BV) at pH 6, compared to 7,000 BVs for pre-treated GAC without pre-corroded steel. Performance was not as good at pH 6.5 or 7.5. Idling the system recovered the iron corrosion ability by reducing the passive Fe(III) layer on pre-corroded steel surface, as a result the BVs to arsenic breakthrough was doubled. But idling also caused brief periods of arsenic and iron release after restart, due to reductive dissolution of arsenic-containing ferric oxides. GAC was also effective as filtration media for removal of iron (hydr)oxide particles (and associated arsenic) that was released from the pre-corroded iron.

  9. An experimental investigation of the seismic behavior of semi-supported steel shear walls

    DEFF Research Database (Denmark)

    Jahanpour, Alireza; Jönsson, Jeppe; Moharrami, H.

    2010-01-01

    A semi-supported steel shear wall (SSSW) has been developed in the recent decade, the steel wall is connected to secondary columns that do not carry vertical loads and are used to enable the plate to enter into the post buckling region and develop a tension field. Theoretical research...... on this system has been performed and an algorithmic method has been developed, which enables the determination of the ultimate capacity of the wall. In this paper results from an experimental investigation of this type of system including two half scale models under cyclic quasi static loading will be presented...

  10. Buckling driven debonding in sandwich columns

    DEFF Research Database (Denmark)

    Østergaard, Rasmus Christian

    2008-01-01

    A compression loaded sandwich column that contains a debond is analyzed using a geometrically non-linear finite element model. The model includes a cohesive zone along one face sheet/core interface whereby the debond can extend by interface crack growth. Two geometrical imperfections are introduced......; a global imperfection of the sandwich column axis and a local imperfection of the debonded face sheet axis. The model predicts the sandwich column to be very sensitive to the initial debond length and the local face sheet imperfection. The study shows that the sensitivity to the face sheet imperfection...... results from two mechanisms: (a) interaction of local debond buckling and global buckling and (b) the development of a damaged zone at the debond crack tip. Based on the pronounced imperfection sensitivity, the author predicts that an experimental measurement of the strength of sandwich structures may...

  11. Non-planar microfabricated gas chromatography column

    Science.gov (United States)

    Lewis, Patrick R.; Wheeler, David R.

    2007-09-25

    A non-planar microfabricated gas chromatography column comprises a planar substrate having a plurality of through holes, a top lid and a bottom lid bonded to opposite surfaces of the planar substrate, and inlet and outlet ports for injection of a sample gas and elution of separated analytes. A plurality of such planar substrates can be aligned and stacked to provide a longer column length having a small footprint. Furthermore, two or more separate channels can enable multi-channel or multi-dimensional gas chromatography. The through holes preferably have a circular cross section and can be coated with a stationary phase material or packed with a porous packing material. Importantly, uniform stationary phase coatings can be obtained and band broadening can be minimized with the circular channels. A heating or cooling element can be disposed on at least one of the lids to enable temperature programming of the column.

  12. Computational analysis of ozonation in bubble columns

    Energy Technology Data Exchange (ETDEWEB)

    Quinones-Bolanos, E. [Univ. of Guelph, School of Engineering, Guelph, Ontario (Canada)]|[Univ. de Cartagena, Facultad de Ciencias e Ingenieria, Cartagena de Indias (Colombia); Zhou, H.; Otten, L. [Univ. of Guelph, School of Engineering, Guelph, Ontario (Canada)]. E-mail: hzhou@uoguelph.ca

    2002-06-15

    This paper presents a new computational ozonation model based on the principle of computational fluid dynamics along with the kinetics of ozone decay and microbial inactivation to predict the performance of ozone disinfection in fine bubble columns. The model can be represented using a mixture two-phase flow model to simulate the hydrodynamics of the water flow and using two transport equations to track the concentration profiles of ozone and microorganisms along the height of the column, respectively. The applicability of this model was then demonstrated by comparing the simulated ozone concentrations with experimental measurements obtained from a pilot scale fine bubble column. One distinct advantage of this approach is that it does not require the prerequisite assumptions such as plug flow condition, perfect mixing, tanks-in-series, uniform radial or longitudinal dispersion in predicting the performance of disinfection contactors without carrying out expensive and tedious tracer studies. (author)

  13. Methylmercury production in the marine water column

    Science.gov (United States)

    Topping, G.; Davies, I. M.

    1981-03-01

    Although the biosynthesis of methylmercury in sediments is well established1, this is not necessarily the exclusive natural source of methylmercury entering the marine food chain, particularly commercial fish and shellfish species for human consumption. An examination of mercury levels in freshwater fish2, collected from a lake with a history of industrial mercury contamination, suggested that levels in fish are controlled in part by mercury in suspension and it followed that methylation should occur in the water column. Although methylmercury is present in seawater in coastal areas receiving discharges of waste containing either inorganic mercury3 or methylmercury4 there is no evidence that methylmercury is actually formed in the water column. We now present data which demonstrate that inorganic mercury can be methylated in the water column and we compare this production with that known to occur in marine sediments.

  14. Neutron camera employing row and column summations

    Science.gov (United States)

    Clonts, Lloyd G.; Diawara, Yacouba; Donahue, Jr, Cornelius; Montcalm, Christopher A.; Riedel, Richard A.; Visscher, Theodore

    2016-06-14

    For each photomultiplier tube in an Anger camera, an R.times.S array of preamplifiers is provided to detect electrons generated within the photomultiplier tube. The outputs of the preamplifiers are digitized to measure the magnitude of the signals from each preamplifier. For each photomultiplier tube, a corresponding summation circuitry including R row summation circuits and S column summation circuits numerically add the magnitudes of the signals from preamplifiers for each row and for each column to generate histograms. For a P.times.Q array of photomultiplier tubes, P.times.Q summation circuitries generate P.times.Q row histograms including R entries and P.times.Q column histograms including S entries. The total set of histograms include P.times.Q.times.(R+S) entries, which can be analyzed by a position calculation circuit to determine the locations of events (detection of a neutron).

  15. Effect of Neutron Irradiation on Beam-Column Interaction of Reinforced Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Tae-Hyun; Park, Jiho; Kim, Jun Yeon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, HyungTae; Park, Kyoungsoo [Yonsei University, Seoul (Korea, Republic of); Kim, Sang-Ho [Hyundai Engineering, Seoul (Korea, Republic of)

    2015-10-15

    Age-related effects on such RC structures have been extensively studied in detail. However, the effect of neutron irradiation requires further studies from its limited database. Most of RC structures have been regarded as sound as the neutron fluence below 1.0x10{sup 19} n/cm{sup 2}. The reduction of strength is not considered in a periodic inspection program at aging NPPs. However, RC structures, such as biological shields and supports for a reactor vessel, could be exposed to see the critical level of neutron fluence at years of operation. In this regard, beam-column interaction of a typical RC member is numerically investigated as a result of neutron irradiation. The effect of neutron irradiation on beam-column interaction is evaluated. ACI318 requires the strength reduction factor, ϕ=0.70, for the compression controlled area and the higher up to 0.9 as the tensile strain in steel reinforcement goes higher. This concept works well with this example. However, this does not take into account the energy dissipation capacity of the member but it only expresses the ultimate strength. Therefore, the current strength evaluation concept may be misleading when the material behavior of steel reinforcement becomes brittle due to the neutron irradiation. In such case, even for the transient and tension controlled area, the strength reduction factor needs to be modified to account for the potential ductility loss.

  16. Accelerating selected columns of the density matrix computations via approximate column selection

    CERN Document Server

    Damle, Anil; Ying, Lexing

    2016-01-01

    Localized representation of the Kohn-Sham subspace plays an important role in quantum chemistry and materials science. The recently developed selected columns of the density matrix (SCDM) method [J. Chem. Theory Comput. 11, 1463, 2015] is a simple and robust procedure for finding a localized representation of a set of Kohn-Sham orbitals from an insulating system. The SCDM method allows the direct construction of a well conditioned (or even orthonormal) and localized basis for the Kohn-Sham subspace. The SCDM procedure avoids the use of an optimization procedure and does not depend on any adjustable parameters. The most computationally expensive step of the SCDM method is a column pivoted QR factorization that identifies the important columns for constructing the localized basis set. In this paper, we develop a two stage approximate column selection strategy to find the important columns at much lower computational cost. We demonstrate the effectiveness of this process using a dissociation process of a BH$_{3}...

  17. Final Report, Distillation Column Flooding Predictor

    Energy Technology Data Exchange (ETDEWEB)

    George E. Dzyacky

    2003-05-31

    The Flooding Predictor is an advanced process control strategy comprising a patented pattern-recognition methodology that identifies pre-flood patterns discovered to precede flooding events in distillation columns. The grantee holds a U.S. patent on the modeling system. The technology was validated at the Separations Research Program, The University of Texas at Austin under a grant from the U. S. Department of Energy, Inventions & Innovation Program. Distillation tower flooding occurs at abnormally high vapor and/or liquid rates. The loss in tray efficiencies is attributed to unusual behavior of liquid inventories inside the column leading to conditions of flooding of the space in between trays with liquid. Depending on the severity of the flood condition, consequences range from off spec products to equipment damage and tower shutdown. This non-intrusive pattern recognition methodology, processes signal data obtained from existing column instrumentation. Once the pattern is identified empirically, it is modeled and coded into the plant's distributed control system. The control system is programmed to briefly "unload" the tower each time the pattern appears. The unloading takes the form of a momentary reduction in column severity, e.g., decrease bottom temperature, reflux or tower throughput. Unloading the tower briefly at the pre-flood state causes long-term column operation to become significantly more stable - allowing an increase in throughput and/or product purity. The technology provides a wide range of value between optimization and flooding. When a distillation column is not running at capacity, it should be run in such a way ("pushed") that optimal product purity is achieved. Additional benefits include low implementation and maintenance costs, and a high level of console operator acceptance. The previous commercial applications experienced 98% uptime over a four-year period. Further, the technology is unique in its ability to distinguish between

  18. Retention Models on Core-Shell Columns.

    Science.gov (United States)

    Jandera, Pavel; Hájek, Tomáš; Růžičková, Marie

    2017-07-13

    A thin, active shell layer on core-shell columns provides high efficiency in HPLC at moderately high pressures. We revisited three models of mobile phase effects on retention for core-shell columns in mixed aqueous-organic mobile phases: linear solvent strength and Snyder-Soczewiński two-parameter models and a three-parameter model. For some compounds, two-parameter models show minor deviations from linearity due to neglect of possible minor retention in pure weak solvent, which is compensated for in the three-parameter model, which does not explicitly assume either the adsorption or the partition retention mechanism in normal- or reversed-phase systems. The model retention equation can be formulated as a function of solute retention factors of nonionic compounds in pure organic solvent and in pure water (or aqueous buffer) and of the volume fraction of an either aqueous or organic solvent component in a two-component mobile phase. With core-shell columns, the impervious solid core does not participate in the retention process. Hence, the thermodynamic retention factors, defined as the ratio of the mass of the analyte mass contained in the stationary phase to its mass in the mobile phase in the column, should not include the particle core volume. The values of the thermodynamic factors are lower than the retention factors determined using a convention including the inert core in the stationary phase. However, both conventions produce correct results if consistently used to predict the effects of changing mobile phase composition on retention. We compared three types of core-shell columns with C18-, phenyl-hexyl-, and biphenyl-bonded phases. The core-shell columns with phenyl-hexyl- and biphenyl-bonded ligands provided lower errors in two-parameter model predictions for alkylbenzenes, phenolic acids, and flavonoid compounds in comparison with C18-bonded ligands.

  19. Milled Die Steel Surface Roughness Correlation with Steel Sheet Friction

    DEFF Research Database (Denmark)

    Berglund, J.; Brown, C.A.; Rosén, B.-G.

    2010-01-01

    This work investigates correlations between the surface topography ofmilled steel dies and friction with steel sheet. Several die surfaces were prepared by milling. Friction was measured in bending under tension testing. Linear regression coefficients (R2) between the friction and texture...

  20. Complex osteotomies vertebral column resection and decancellation.

    Science.gov (United States)

    Obeid, Ibrahim; Bourghli, Anouar; Boissière, Louis; Vital, Jean-Marc; Barrey, Cédric

    2014-07-01

    Pedicle subtraction osteotomy (PSO) is nowadays widely used to treat sagittal imbalance. Some complex malalignment cases cannot be treated by a PSO, whereas the imbalance is coronal or mixed or the sagittal imbalance is major and cannot be treated by a single PSO. The aim of this article was to review these complex situations--coronal imbalance, mixed imbalance, two-level PSO, vertebral column resection, and vertebral column decancellation, and to focus on their specificities. It wills also to evoke the utility of navigation in these complex cases.

  1. Column flotation in coal: does it make `cents?`

    Energy Technology Data Exchange (ETDEWEB)

    Laurila, M.J.

    1997-01-01

    Column flotation technology was introduced into the coal industry in 1986. The column can produce higher grade concentrates than conventional cells. This has created a niche market for columns in recovering ultrafine (-100 mesh) coal from waste streams. However, column flotation is much more expensive than froth flotation and columns can only process a maximum of 20 tons per hour per unit and consume more reagents than conventional cells. Researchers at Michigan Technological University have found that baffles along the axis of a column vastly improved performance. Today only two companies in the US participate in the column flotation market, ICF Kaiser and Deister.

  2. Behaviour of a Moment Resisting Composite Steel and Concrete Joint Under Alternate Loading

    Institute of Scientific and Technical Information of China (English)

    Alberto Zanchettin; Bruno Briseghella; Tobia Zordan; Junqing Xue

    2011-01-01

    The authors show the results of a study conducted on a joint connecting a concrete column to a composite steel concrete floor, subjected to tension on the beams as a result of the decomposition of sagging bending moment. The beam to column connection is achieved by means of headed studs welded to the beam and embedded in the concrete cast. Five different configurations have been tested at failure and the results are compared to formulae proposed in literature. Different degrees of ductility, reliability and strength have been obtained varying geometry and reinforcement ratio on the joints tested.

  3. Investigating the efficiency of using the carbon fiber polymer on beam–column connection

    Directory of Open Access Journals (Sweden)

    Mahmoud M. Eldeeb

    2016-03-01

    Full Text Available Due to the huge amount of energy induced from earthquakes, such natural hazards usually represent the most significant threat on existing and new buildings. Recently, a lot of considerable efforts were dedicated to design buildings capable of withstanding earthquakes' ground motions by utilizing lateral resisting elements, such as reinforced concrete shear walls, cores, frames, and steel bracing. Contrasting the experience gained from the previously designed guidelines and provisions for lateral resisting systems, recent studies illustrated that the existence of lateral resisting system in low-rise buildings is essential in order to resist ground motions. As such, some endeavors are directed to reinforce old buildings against seismic loads. This paper focuses on investigating the efficiency of using Carbon Fiber Polymer (CFRP sheets on the behavior of beam–column connections considering a cantilever beam with concentrated load at its free end. In addition, to complement the published data, finite element model using the computer package ANSYS was used. The additional beam–column connections in this study are classified in 4 groups (A, B, C, and D depending on the percentage of reinforcement at the bottom and top of the beam (%As. The efficiency of using CFRP was concluded; the CFRP sheet improves or decreases the efficiency of beam–column connection depending on %As in the beam. The paper investigates the influence of boundary condition, columns as hinged supports, and the efficiency of using CFRP. It is concluded that the CFRP sheet improves or decreases the efficiency of beam–column connection depending on %As in the beam.

  4. The industrial practice and development of flotation column in China

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jiongtian; Zhang Shuangquan [China Univ. of Mining and Technology, Xuzhou (China). Dept. of Energy Utilization and Chemical Engineering

    1997-12-31

    This paper reviewed the developing course of the flotation column since the 1960`s in China. Based on the practical data from several coal preparation plants, two types of flotation columns (the pressure aerated column and the jetting-cyclone column) were compared by their operation, performance and the reasons why they succeeded in the coal industry in China. The paper points out that the flotation column has come into commercial use and has good application prospects in China.

  5. Steel designers' handbook

    CERN Document Server

    Gorenc, Branko; Tinyou, Ron

    2012-01-01

    The Revised 7th Edition of Steel Designers' Handbook is an invaluable tool for all practising structural, civil and mechanical engineers as well as engineering students at university and TAFE in Australia and New Zealand. It has been prepared in response to changes in the design Standard AS 4100, the structural Design Actions Standards, AS /ANZ 1170, other processing Standards such as welding and coatings, updated research as well as feedback from users. This edition is based on Australian Standard (AS) 4100: 1998 and subsequent amendments. The worked numerical examples in the book have been e

  6. The industrial ecology of steel

    Energy Technology Data Exchange (ETDEWEB)

    Considine, Timothy J.; Jablonowski, Christopher; Considine, Donita M.M.; Rao, Prasad G.

    2001-03-26

    This study performs an integrated assessment of new technology adoption in the steel industry. New coke, iron, and steel production technologies are discussed, and their economic and environmental characteristics are compared. Based upon detailed plant level data on cost and physical input-output relations by process, this study develops a simple mathematical optimization model of steel process choice. This model is then expanded to a life cycle context, accounting for environmental emissions generated during the production and transportation of energy and material inputs into steelmaking. This life-cycle optimization model provides a basis for evaluating the environmental impacts of existing and new iron and steel technologies. Five different plant configurations are examined, from conventional integrated steel production to completely scrap-based operations. Two cost criteria are used to evaluate technology choice: private and social cost, with the latter including the environmental damages associated with emissions. While scrap-based technologies clearly generate lower emissions in mass terms, their emissions of sulfur dioxide and nitrogen oxides are significantly higher. Using conventional damage cost estimates reported in the literature suggests that the social costs associated with scrap-based steel production are slightly higher than with integrated steel production. This suggests that adopting a life-cycle viewpoint can substantially affect environmental assessment of new technologies. Finally, this study also examines the impacts of carbon taxes on steel production costs and technology choice.

  7. Mechanics in Steels through Microscopy

    NARCIS (Netherlands)

    Tirumalasetty, G.K.

    2013-01-01

    The goal of the study consolidated in this thesis is to understand the mechanics in steels using microscopy. In particular, the mechanical response of Transformation Induced Plasticity (TRIP) steels is correlated with their microstructures. Chapter 1 introduces the current state of the art of TRIP s

  8. Mechanics in Steels through Microscopy

    NARCIS (Netherlands)

    Tirumalasetty, G.K.

    2013-01-01

    The goal of the study consolidated in this thesis is to understand the mechanics in steels using microscopy. In particular, the mechanical response of Transformation Induced Plasticity (TRIP) steels is correlated with their microstructures. Chapter 1 introduces the current state of the art of TRIP

  9. CORROSION INHIBITOR FOR CARBON STEELS

    African Journals Online (AJOL)

    corrosion inhibitor for carbon steel in 3% ac]neon.s' NaCl solution (pH 6) ... compared to stainless steels (Buchweishaija & Hagen 1997). Organic compounds are ... resistant dust for break and clutch linings, wood binders and mould (Gedam.

  10. Hydrogen Embrittlement of Structural Steels

    Energy Technology Data Exchange (ETDEWEB)

    Somerday, Brian P.; San Marchi, Christopher W

    2014-08-01

    Carbon-manganese steels are candidates for the structural materials in hydrogen gas pipelines; however, it is well known that these steels are susceptible to hydrogen embrittlement. Decades of research and industrial experience have established that hydrogen embrittlement compromises the structural integrity of steel components. This experience has also helped identify the failure modes that can operate in hydrogen containment structures. As a result, there are tangible ideas for managing hydrogen embrittlement in steels and quantifying safety margins for steel hydrogen containment structures. For example, fatigue crack growth aided by hydrogen embrittlement is a well-established failure mode for steel hydrogen containment structures subjected to pressure cycling. This pressure cycling represents one of the key differences in operating conditions between current hydrogen pipelines and those anticipated in a hydrogen delivery infrastructure. Applying structural integrity models in design codes coupled with measurement of relevant material properties allows quantification of the reliability/integrity of steel hydrogen pipelines subjected to pressure cycling. Furthermore, application of these structural integrity models is aided by the development of physics-based predictive models, which provide important insights such as the effects of microstructure on hydrogen-assisted fatigue crack growth. Successful implementation of these structural integrity and physics-based models enhances confidence in the design codes and enables decisions about materials selection and operating conditions for reliable and efficient steel hydrogen pipelines.

  11. Great Challenge in Steel Export

    Institute of Scientific and Technical Information of China (English)

    Charlsea Liu

    2009-01-01

    @@ In 2008, the export of China steel products experienoeu, a splendid period f fast growing, and then disappointedly followed by fast depression. Until lest December, China in 2008 exported steel products of 59.21 million tons, less than the same term in 2007 by 3.48 million tons, declining about 5.6%.

  12. Experimental Study on Stress Monitoring of Sand-Filled Steel Tube during Impact Using Piezoceramic Smart Aggregates.

    Science.gov (United States)

    Du, Guofeng; Zhang, Juan; Zhang, Jicheng; Song, Gangbing

    2017-08-22

    The filling of thin-walled steel tubes with quartz sand can help to prevent the premature buckling of the steel tube at a low cost. During an impact, the internal stress of the quartz sand-filled steel tube column is subjected to not only axial force but also lateral confining force, resulting in complicated internal stress. A suitable sensor for monitoring the internal stress of such a structure under an impact is important for structural health monitoring. In this paper, piezoceramic Smart Aggregates (SAs) are embedded into a quartz Sand-Filled Steel Tube Column (SFSTC) to monitor the internal structural stress during impacts. The piezoceramic smart aggregates are first calibrated by an impact hammer. Tests are conducted to study the feasibility of monitoring the internal stress of a structure. The results reflect that the calibration value of the piezoceramic smart aggregate sensitivity test is in good agreement with the theoretical value, and the output voltage value of the piezoceramic smart aggregate has a good linear relationship with external forces. Impact tests are conducted on the sand-filled steel tube with embedded piezoceramic smart aggregates. By analyzing the output signal of the piezoceramic smart aggregates, the internal stress state of the structure can be obtained. Experimental results demonstrated that, under the action of impact loads, the piezoceramic smart aggregates monitor the compressive stress at different locations in the steel tube, which verifies the feasibility of using piezoceramic smart aggregate to monitor the internal stress of a structure.

  13. Reducing axial mixing in flotation columns

    Energy Technology Data Exchange (ETDEWEB)

    Al Taweel, A.M.; Ramadan, A.M. [Technical Univ. of Nova Scotia, Halifax (Canada). Chemical Engineering Dept.; Moharam, M.R.; Hassan, T.A. [Al Azhar Univ., Cairo (Egypt); El Mofty, S.M. [Cairo Univ., Giza (Egypt)

    1995-10-01

    The axial mixing characteristics of a pilot-scale flotation column were investigated with the objective of identifying means to mitigate the extent of axial mixing that adversely affects its grade/recovery performance. A wide range of design and operating conditions wa investigated and the experimental results, obtained using the dynamic response method, were analyzed using three axial mixing models. The dynamic response of the column can best be described using the axial dispersion model. The results obtained suggest that the value of the axial dispersion coefficient, E{sub L}, can be significantly reduced by judicial selection of hydrodynamic conditions and/or the use of column inserts that suppress the onset of hydrodynamic instabilities inherent to the operation of conventional flotation columns. Up to 40% reduction in the value of E{sub L} was thus obtained by using spargers that produce more uniform bubble sizes, while up to 30% reductions were obtained by controlling the residual frother concentration. 33 refs., 7 figs.

  14. On Row Rank Equal Column Rank

    Science.gov (United States)

    Khalili, Parviz

    2009-01-01

    We will prove a well-known theorem in Linear Algebra, that is, for any "m x n" matrix the dimension of row space and column space are the same. The proof is based on the subject of "elementary matrices" and "reduced row-echelon" form of a matrix.

  15. Robust Geometric Control of a Distillation Column

    DEFF Research Database (Denmark)

    Kymmel, Mogens; Andersen, Henrik Weisberg

    1987-01-01

    A frequency domain method, which makes it possible to adjust multivariable controllers with respect to both nominal performance and robustness, is presented. The basic idea in the approach is that the designer assigns objectives such as steady-state tracking, maximum resonance peaks, bandwidth, m...... is used to examine and improve geometric control of a binary distillation column....

  16. The Special Column of Primate Behavior

    Institute of Scientific and Technical Information of China (English)

    Baoguo LI; Guest Editor

    2010-01-01

    @@ It is a long-term policy to publish SPECIAL COLUMNs in Current Zoology, and I am delighted that the journal is publishing this special colunm devoted to the topic of Primate Behavior. The eight papers in this seetion present significant new data and synthesize these findings with existing information on sexual selection of human-being and behaviors of living primates.

  17. Thermal Analysis of LANL Ion Exchange Column

    Energy Technology Data Exchange (ETDEWEB)

    Laurinat, J.E.

    1999-06-16

    This document reports results from an ion exchange column heat transfer analysis requested by Los Alamos National Laboratory (LANL). The object of the analysis is to demonstrate that the decay heat from the Pu-238 will not cause resin bed temperatures to increase to a level where the resin significantly degrades.

  18. "Dry-column" chromatography of plant pigments

    Science.gov (United States)

    Woeller, F. H.; Lehwalt, M. F.; Oyama, V. I.

    1973-01-01

    Separation of plant pigments which can be accomplished on thin-layer silica plates with mixture of petroleum ether, halocarbon, acetone, and polar solvent can be readily translated into dry-column technique that yields reproducible chromatograms after elution in fashion of liquid chromatography with fluorimeter as detector. Best solvent system was found to be mixture of petroleum ether, dichloromethane, acetone, and ethyl acetate.

  19. WATER COLUMN DATA AND SPECTRAL IRRADIANCE MODEL

    Science.gov (United States)

    Water samples collected monthly, for 18 months, from six sites in the Laguna Madre were analyzed to identify and quantify phytopigments using High Performance Liquid Chromatography (HPLC). In addition, water column pigment and nutrient data were acquired at 12 stations in Upper ...

  20. Flexural buckling of fire exposed aluminium columns

    NARCIS (Netherlands)

    Maljaars, J.; Twilt, L.; Soetens, F.

    2009-01-01

    In order to study buckling of fire exposed aluminium columns, a finite element model is developed. The results of this model are verified with experiments. Based on a parametric study with the finite element model, it is concluded that the simple calculation model for flexural buckling of fire expos

  1. Contexts for Column Addition and Subtraction

    Science.gov (United States)

    Lopez Fernandez, Jorge M.; Velazquez Estrella, Aileen

    2011-01-01

    In this article, the authors discuss their approach to column addition and subtraction algorithms. Adapting an original idea of Paul Cobb and Erna Yackel's from "A Contextual Investigation of Three-Digit Addition and Subtraction" related to packing and unpacking candy in a candy factory, the authors provided an analogous context by…

  2. Contexts for Column Addition and Subtraction

    Science.gov (United States)

    Lopez Fernandez, Jorge M.; Velazquez Estrella, Aileen

    2011-01-01

    In this article, the authors discuss their approach to column addition and subtraction algorithms. Adapting an original idea of Paul Cobb and Erna Yackel's from "A Contextual Investigation of Three-Digit Addition and Subtraction" related to packing and unpacking candy in a candy factory, the authors provided an analogous context by…

  3. Steels from materials science to structural engineering

    CERN Document Server

    Sha, Wei

    2013-01-01

    Steels and computer-based modelling are fast growing fields in materials science as well as structural engineering, demonstrated by the large amount of recent literature. Steels: From Materials Science to Structural Engineering combines steels research and model development, including the application of modelling techniques in steels.  The latest research includes structural engineering modelling, and novel, prototype alloy steels such as heat-resistant steel, nitride-strengthened ferritic/martensitic steel and low nickel maraging steel.  Researchers studying steels will find the topics vital to their work.  Materials experts will be able to learn about steels used in structural engineering as well as modelling and apply this increasingly important technique in their steel materials research and development. 

  4. Design of heavy steel structure building in soft area%某重钢结构在软土地区的设计

    Institute of Scientific and Technical Information of China (English)

    陈卉

    2012-01-01

    介绍了某重钢结构在软土地区的设计,包括钢柱、吊车梁选型、抗风桁架柱、支撑、檁条及桩基础等设计。%The design of heavy steel structure building in soft soil area is introduced,including the design of the steel column,selection of crane beam,wind resistant column and truss,brace,strip and pile base.

  5. Nanoprecipitation in bearing steels

    Energy Technology Data Exchange (ETDEWEB)

    Barrow, A.T.W. [SKF University Technology Centre, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ (United Kingdom); Rivera-Diaz-del-Castillo, P.E.J., E-mail: pejr2@cam.ac.uk [SKF University Technology Centre, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ (United Kingdom)

    2011-11-15

    {theta}-phase is the main hardening species in bearing steels and appears in both martensitically and bainitically hardened microstructures. This work presents a survey of the microstrucural features accompanying nanoprecipitation in bearing steels. Nanoprecipitate structures formed in 1C-1.5Cr wt.% with additions of Cr, Mn, Mo, Si and Ni are studied. The work is combined with thermodynamic calculations and neural networks to predict the expected matrix composition, and whether this will transform martensitically or bainitically. Martensite tetragonality, composition and the amount of retained austenite are related to hardness and the type of nanoprecipitate structures in martensitic grades. The {theta}-phase volume fraction, the duration of the bainite to austenite transformation and the amount of retained austenite are related to hardness and a detailed quantitative description of the precipitate nanostructures. Such description includes compositional studies using energy-dispersive spectroscopy, which shows that nanoprecipitate formation takes place under paraequilibrium. Special attention is devoted to a novel two-step bainite tempering process which shows maximum hardness; we prove that this is the most effective process for incorporating solute into the precipitates, which are finer than those resulting from one-step banitic transformation processes.

  6. Influence of the steel scrap classes on the liquid steel output molten in electric steel processes

    Directory of Open Access Journals (Sweden)

    K. Janiszewski

    2012-12-01

    Full Text Available Purpose: This is why we have analysed in the paper, using statistical analysing methods, the influence of use in the electric arc furnace charges of steel scrap of different qualities on the index of liquid steel output from a melt.Design/methodology/approach: The used research methodology consists in analytical simulation of variations in mass of liquid steel obtained from melts differing in steel scrap content in the metallic charge and statistical analyses of industrial results acquired from the corresponding process documentation (so called melt cards.Findings: Basing on the analytical and statistical analyses carried out we have determine resulting variations in the liquid steel per melt ratios depending on the content of steel scrap in the metallic charge.Research limitations/implications: The research results obtained can be utilized in each steelmaking facility, which employs the Electric Steelmaking process, in order to “design” the metallic charge compositions, having in view the quality and economic aspects.Practical implications: The research results presented in the paper can be used for steel production of high purity steels.Originality/value: The results presented in this paper are directed to the steelmakers employing the Electric Steelmaking process and constitute the authors’ original study.

  7. Analysis of multistoried braced steel space frame subjected to gravity and seismic loading.

    Directory of Open Access Journals (Sweden)

    Dhananjay.S.Pawar

    2015-09-01

    Full Text Available Steel structures are generally more flexible than other types of structure and lower in weight. Earthquake loads are random in nature. It is difficult to predict them exactly. The action applied to a structure by an earthquake is a ground movement with horizontal and vertical components. The horizontal movement is the most specific feature of earthquake action because of its strength and because structures are generally better designed to resist gravity than horizontal forces. These forces produce large stresses, strains, deformation and displacement particularly in tall structures. To keep displacement within limit generally bracing is provided in steel structure. . Bracings are generally used to increase lateral-stiffness, lateral- strength as well as lateral stability of the frame. Variations in the column stiffness can influence the mode of failure and lateral stiffness of the bracing. In this study steel frame is modeled and analyzed three Parts viz., (i Model without Steel bracing (bare frame, (ii Model completely with fully braced steel frame („Cross‟ bracing, (iii Model completely with fully braced steel frame („Single diagonal‟ bracing.

  8. Study on Seismic Performance of a Stiffened Steel Plate Shear Wall with Slits

    Directory of Open Access Journals (Sweden)

    Jin-yu Lu

    2015-01-01

    Full Text Available To determine the force mechanism for the steel plate shear wall with slits, the pushover analysis method was used in this study. An estimated equation for the lateral bearing capacity which considered the effect of edge stiffener was proposed. A simplified elastic-plastic analytical model for the stiffened steel slit wall composed of beam elements was presented, where the effects of edge stiffeners were taken into account. The wall-frame analysis model was established, and the geometric parameters were defined. Pushover analysis of two specimens was carried out, and the analysis was validated by comparing the results from the experiment, the shell element model, and a simplified model. The simplified model provided a good prediction of the lateral stiffness and the strength of the steel slit wall, with less than 10% error compared with the experimental results. The mutual effects of the bearing wall and the frame were also predicted correctly. In the end, the seismic performance evaluation of a steel slit wall-frame structure was presented. The results showed that the steel slit wall could prevent the beams and columns from being damaged by an earthquake and that the steel slit wall was an efficient energy dissipation component.

  9. Computer-Aided Construction at Designing Reinforced Concrete Columns as Per Ec

    Directory of Open Access Journals (Sweden)

    Zielińska M.

    2015-02-01

    Full Text Available The article presents the authors’ computer program for designing and dimensioning columns in reinforced concrete structures taking into account phenomena affecting their behaviour and information referring to design as per EC. The computer program was developed with the use of C++ programming language. The program guides the user through particular dimensioning stages: from introducing basic data such as dimensions, concrete class, reinforcing steel class and forces affecting the column, through calculating the creep coefficient taking into account the impact of imperfection depending on the support scheme and also the number of mating members at load shit, buckling length, to generating the interaction curve graph. The final result of calculations provides two dependence points calculated as per methods of nominal stiffness and nominal curvature. The location of those points relative to the limit curve determines whether the column load capacity is assured or has been exceeded. The content of the study describes in detail the operation of the computer program and the methodology and phenomena which are indispensable at designing axially and eccentrically the compressed members of reinforced concrete structures as per the European standards.

  10. Measurement of buckling load for metallic plate columns in severe accident conditions

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Byeongnam, E-mail: jo@vis.t.u-tokyo.ac.jp; Sagawa, Wataru, E-mail: sagawa@vis.t.u-tokyo.ac.jp; Okamoto, Koji, E-mail: okamoto@n.t.u-tokyo.ac.jp

    2014-07-01

    Highlights: • Buckling load was experimentally measured in a wide range of temperature up to 1200 °C. • Two different test methods for measuring buckling failure load were suggested and compared. • Creep buckling under compressive load was performed to explain results of buckling tests. • Reduced buckling load was explained by effects of creep buckling, geometrical imperfection, and thermal stress. • Buckling processes were visualized by a high speed camera. - Abstract: In severe accidents, a reactor pressure vessel, its components, and piping have to be under extremely high temperature and high pressure conditions, which results in failure modes like rupture by internal pressure, buckling, creep, and their combinations. In this study, buckling (failure) load was experimentally measured for metallic columns under the compressive force from room temperature up to 1200 °C. A stainless steel was chosen to be a test material to measure the buckling load. Two different test methods were employed to explore the effect of thermal history of the material on the buckling load. Particularly, the effect of creep under a compressive load was considered as a reason for the reduced buckling load at high temperatures. Additionally, finite element simulations were also conducted to predict buckling load for both an ideal column and a column with geometrical imperfection as well. Moreover, buckling process was visualized using a high speed camera to understand buckling processes.

  11. Continuous aqueous two-phase extraction of human antibodies using a packed column.

    Science.gov (United States)

    Rosa, P A J; Azevedo, A M; Sommerfeld, S; Bäcker, W; Aires-Barros, M R

    2012-01-01

    The performance of a pilot scale packed differential contactor was evaluated for the continuous counter-current aqueous two-phase extraction (ATPE) of human immunoglobulin G (IgG) from a Chinese hamster ovary (CHO) cells supernatant (CS) enriched with pure protein. Preliminary studies have been firstly performed in order to select the dispersed phase (phosphate-rich or polyethylene glycol 3350 Da (PEG)-rich phase) and the column packing material. The PEG-rich phase has been selected as the dispersed phase and the stainless steel as the preferred material for the column packing bed since it was not wetted preferentially by the selected dispersed phase. Hydrodynamic studies have been also performed, and the experimental results were successfully adjusted to the Richardson-Zaki and Mísek equations, typically used for the conventional organic-aqueous two-phase systems. An experimental set-up combining the packed column with a pump mixer-settler stage showed to have the best performance and to be advantageous when compared to the IgG batch extraction. An IgG recovery yield of 85% could be obtained with about 50% of total contaminants and more than 85% of contaminant proteins removal. Mass transfer studies have revealed that the mass transfer was controlled by the PEG-rich phase. A higher efficiency could be obtained when using an extra pump mixer-settler stage and higher flow rates.

  12. Composite support column assembly for offshore drilling and production platforms

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, R.H.

    1989-04-18

    This patent describes a support column assembly for an offshore drilling and/or production comprising: means for anchoring the column assembly on the seabed; an elongated cylindrical support column including at least one generally cylindrical column member having a cylindrical wall formed of a composite of elongated filaments of at least one of carbon and boron bonded in a resin matrix, the support column including a plurality of the column members coupled end to end by coupling means at opposite ends of the column members, the coupling means including a plurality of radially project pins for coupling the composite wall to a coupling member interposed between the column members, respectively; and means for connecting the column to a platform for transmitting platform loads between the platform and the anchor means.

  13. An experimental investigation of innovative bridge columns with engineered cementitious composites and Cu-Al-Mn super-elastic alloys

    Science.gov (United States)

    Hosseini, F.; Gencturk, B.; Lahpour, S.; Ibague Gil, D.

    2015-08-01

    Recent strong earthquakes have shown that reinforced concrete (RC) bridge columns constructed using conventional materials and techniques suffer from major damage and permanent deformations. The yielding of the longitudinal reinforcement as the main source of energy absorption, and cracking and spalling of concrete results in a dysfunctional bridge structure that does not support the post-disaster recovery efforts. This paper investigates the use of engineered cementitious composites (ECCs) and Cu-Al-Mn super-elastic alloys (SEAs) to improve the performance of bridge columns under seismic loads. A new column design is proposed, which is composed of a pre-fabricated ECC tube that encompasses the longitudinal and transverse steel reinforcement (rebar). The rebar in the plastic hinge region of the cantilever columns was totally or partially replaced with Cu-Al-Mn SEA bars. The tube was filled with conventional concrete after it was placed inside the rebar cage of the foundation. ECC exhibits superior tensile ductility, bonding with steel, energy absorption and shear resistance, in addition to lower permeability and reduced crack widths compared to conventional concrete. Cu-Al-Mn SEA bars are capable of recovering large inelastic deformations exceeding 12% strain. The proposed approach capitalizes on the deformability of ECC with reduced damage, and the energy absorption capacity of Cu-Al-Mn SEA bars without permanent deformation. A total of six column specimens were constructed and tested under simulated seismic loading. The number of rebars replaced with Cu-Al-Mn SEA bars, ECC mixture design, and the ratio of the concrete core area to total column cross-sectional area were the variables investigated in the test program. A comparison of the results indicated that the proposed concept with no Cu-Al-Mn SEA bars provides higher lateral strength, similar energy absorption and reduced damage compared to conventional RC columns; however, similar to a conventional column, it

  14. On-column nitrosation of amines observed in liquid chromatography impurity separations employing ammonium hydroxide and acetonitrile as mobile phase.

    Science.gov (United States)

    Myers, David P; Hetrick, Evan M; Liang, Zhongming; Hadden, Chad E; Bandy, Steven; Kemp, Craig A; Harris, Thomas M; Baertschi, Steven W

    2013-12-06

    The availability of high performance liquid chromatography (HPLC) columns capable of operation at pH values up to 12 has allowed a greater selectivity space to be explored for method development in pharmaceutical analysis. Ammonium hydroxide is of particular value in the mobile phase because it is compatible with direct interfacing to electrospray mass spectrometers. This paper reports an unexpected N-nitrosation reaction that occurs with analytes containing primary and secondary amines when ammonium hydroxide is used to achieve the high pH and acetonitrile is used as the organic modifier. The nitrosation reaction has generality. It has been observed on multiple columns from different vendors and with multiple amine-containing analytes. Ammonia was established to be the source of the nitroso nitrogen. The stainless steel column frit and metal ablated from the frit have been shown to be the sites of the reactions. The process is initiated by removal of the chromium oxide protective film from the stainless steel by acetonitrile. It is hypothesized that the highly active, freshly exposed metals catalyze room temperature oxidation of ammonia to NO but that the actual nitrosating agent is likely N(2)O(3).

  15. Improving the toughness of ultrahigh strength steel

    Energy Technology Data Exchange (ETDEWEB)

    Soto, Koji

    2002-08-15

    The ideal structural steel combines high strength with high fracture toughness. This dissertation discusses the toughening mechanism of the Fe/Co/Ni/Cr/Mo/C steel, AerMet 100, which has the highest toughness/strength combination among all commercial ultrahigh strength steels. The possibility of improving the toughness of this steel was examined by considering several relevant factors.

  16. 49 CFR 192.55 - Steel pipe.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Steel pipe. 192.55 Section 192.55 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.55 Steel pipe. (a) New steel pipe is... in accordance with paragraph (c) or (d) of this section. (b) Used steel pipe is qualified for use...

  17. Do column frits contribute to the on-column, flow-induced degradation of macromolecules?

    Science.gov (United States)

    Striegel, André M

    2014-09-12

    Flow-induced, on-column degradation is a major hindrance to the accurate characterization of ultra-high molar mass macromolecules and colloids. This degradation is a direct result of the large shear rates which are generated within the column, which cause chain scission to occur both in the interstitial medium and, it has been postulated, at the packing particle pore boundary. An additional putative source of degradation has been the column frits, though little experimental evidence exists to either support or refute this claim. To this effect, the present experiments examine the role of the frits in the degradation of high molar mass macromolecules. Two narrow dispersity polystyrene standards, the molar mass of which differs by a factor of two, were analyzed on three different size-exclusion chromatography (SEC) columns, each with frits of different pore size, at various flow rates. In the smallest pore size column, which also contained the smallest frits and which was packed with the smallest diameter particles, the larger standard was forced to degrade by increasing the flow rate of the mobile phase. During the course of the latter portion of the study, the inlet and the outlet frits were removed from the column, in stepwise fashion. It was concluded that neither frit played any appreciable role in the degradation. Results of our studies were applied to explain previously observed degradation in ultra-high pressure liquid chromatography of polymers. The general conclusion arrived at herein is that the column frits are likely to have a secondary role (as compared to interstitial and pore boundary stresses), or no role at all, in polymer degradation for cases where the frit radius is larger than or equal to the hydraulic radius rcof the column.

  18. Stahlschüssel key to steel

    CERN Document Server

    Wegst, W S

    2016-01-01

    The Key to Steel (Stahlschlüssel/Stahlschluessel) cross reference book will help you to decode / decipher steel designations and find equivalent materials worldwide. The 2016 edition includes more than 70,000 standard designations and trade names from approximately 300 steelmakers and suppliers. Presentation is trilingual: English, French, and German. Materials covered include structural steels, tool steels, valve steels, high temperature steels and alloys, stainless and heat-resisting steels, and more. Standards and designations from 25 countries are cross-referenced.

  19. EFFECT OF LINK DIMENSIONS ON D TYPE ECCENTRIC STEEL FRAMES

    Directory of Open Access Journals (Sweden)

    Mazen Ali Musmar

    2013-01-01

    Full Text Available In seismic prone regions, buildings are designed to maintain sufficient stiffness during moderate earthquakes and to absorb and dissipate a large amount of the energy released due to severe earthquakes. The usual steel framing systems; the moment frames require larger member sections to satisfy stiffness requirements and have large ductility capacity, the concentrically braced frames satisfy stiffness on the expense of ductility requirements, resulting in poor energy dissipation. This study deals with the eccentrically Braced Steel Frames (EBF. EBF configuration is similar to traditional braced frames with the exception that at least one end of each brace must be eccentrically connected to the frame. The energy dissipation is achieved through the yielding of a beam segment called the link, while the other frame members, including outer beam segments, braces and columns, should remain essentially elastic. EBFs offer an economical steel framing system satisfying both stiffness and ductility requirements. The study incorporates conducting nonlinear finite element analysis to study the effect of the link length and link section on the behavior of D types EBF systems. The study involves material and geometric nonlinearities.

  20. Experimental Verification of Steel Pipe Collapse under Vacuum Pressure Conditions

    Science.gov (United States)

    Autrique, R.; Rodal, E.

    2016-11-01

    Steel pipes are used widely in hydroelectric systems and in pumping systems. Both systems are subject to hydraulic transient effects caused by changes in boundary conditions, such as sudden valve closures, pump failures, or accidents. Water column separation, and its associated vaporization pressure inside the pipe, can cause the collapse of thin walled steel pipes subject to atmospheric pressure, as happened during the well known Oigawa Power Plant accident in Japan, in 1950. The conditions under which thin walled pipes subject to external pressure can collapse have been studied mathematically since the second half of the XIX century, with classical authors Southwell and Von Mises obtaining definitive equations for long and short pipes in the second decade of the XX century, in which the fundamental variables are the diameter to thickness ratio D/t and the length to diameter ratio L/D. In this paper, the predicted critical D/t ratio for steel pipe collapse is verified experimentally, in a physical model able to reproduce hydraulic transients, generating vacuum pressures through rapid upstream valve closures.

  1. Separation of Oil from Wastewater by Column Flotation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new type of device, a dissolved-air flotation column, was developed for separation of oily wastewater.The unique design idea of the dissolved-air flotation column is the combined use of dissolved-air flotation and column flotation.The dissolved air release occurred within the column separation system.As a potential application the column was investigated for its performance in separating emulsified oil droplets in oily wastewater.A high separation efficiency was obtained in a series of tests.The aeration performance of the bubble generator used in the dissolved-air flotation column was also studied in particular.

  2. Synchronized oscillation in a modular neural network composed of columns

    Institute of Scientific and Technical Information of China (English)

    LI; Su; QI; Xianglin; HU; Hong; WANG; Yunjiu

    2005-01-01

    The columnar organization is a ubiquitous feature in the cerebral cortex. In this study, a neural network model simulating the cortical columns has been constructed. When fed with random pulse input with constant rate, a column generates synchronized oscillations, with a frequency varying from 3 to 43 Hz depending on parameter values. The behavior of the model under periodic stimulation was studied and the input-output relationship was non-linear. When identical columns were sparsely interconnected, the column oscillator could be locked in synchrony. In a network composed of heterogeneous columns, the columns were organized by intrinsic properties and formed partially synchronized assemblies.

  3. Operation of a Batch Stripping Distillation Column

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A stripping batch distillation column is preferred when the amount of the light component in the feed is small and the products are to be recovered at high purity. The operation modes of a batch stripping are believed to be the same as those of a rectifier. However, the control system of a stripper is different. In this paper, we explore three different control methods with Hysys (Hyprotech Ltd. 1997) for a batch stripper. The main difference is the control scheme for reboiler liquid level: (a) controlled by reflux flow; (b) controlled by reboiler heat duty; (c) controlled by bottom product flow. The main characteristics of operating a batch stripper with different control scheme are presented in this paper. Guidelines are provided for the startup of a batch stripper, the effects of somecontrol tuning parameters on the column performance are discussed.

  4. Pressure drop in CIM disk monolithic columns.

    Science.gov (United States)

    Mihelic, Igor; Nemec, Damjan; Podgornik, Ales; Koloini, Tine

    2005-02-11

    Pressure drop analysis in commercial CIM disk monolithic columns is presented. Experimental measurements of pressure drop are compared to hydrodynamic models usually employed for prediction of pressure drop in packed beds, e.g. free surface model and capillary model applying hydraulic radius concept. However, the comparison between pressure drop in monolith and adequate packed bed give unexpected results. Pressure drop in a CIM disk monolithic column is approximately 50% lower than in an adequate packed bed of spheres having the same hydraulic radius as CIM disk monolith; meaning they both have the same porosity and the same specific surface area. This phenomenon seems to be a consequence of the monolithic porous structure which is quite different in terms of the pore size distribution and parallel pore nonuniformity compared to the one in conventional packed beds. The number of self-similar levels for the CIM monoliths was estimated to be between 1.03 and 2.75.

  5. Modeling of Crystalline Silicotitanate Ion Exchange Columns

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.D.

    1999-03-09

    Non-elutable ion exchange is being considered as a potential replacement for the In-Tank Precipitation process for removing cesium from Savannah River Site (SRS) radioactive waste. Crystalline silicotitanate (CST) particles are the reference ion exchange medium for the process. A major factor in the construction cost of this process is the size of the ion exchange column required to meet product specifications for decontaminated waste. To validate SRS column sizing calculations, SRS subcontracted two reknowned experts in this field to perform similar calculations: Professor R. G. Anthony, Department of Chemical Engineering, Texas A&038;M University, and Professor S. W. Wang, Department of Chemical Engineering, Purdue University. The appendices of this document contain reports from the two subcontractors. Definition of the design problem came through several meetings and conference calls between the participants and SRS personnel over the past few months. This document summarizes the problem definition and results from the two reports.

  6. Cold-formed steel design

    CERN Document Server

    Yu, Wei-Wen

    2010-01-01

    The definitive text in the field, thoroughly updated and expanded Hailed by professionals around the world as the definitive text on the subject, Cold-Formed Steel Design is an indispensable resource for all who design for and work with cold-formed steel. No other book provides such exhaustive coverage of both the theory and practice of cold-formed steel construction. Updated and expanded to reflect all the important developments that have occurred in the field over the past decade, this Fourth Edition of the classic text provides you with more of the detailed, up-to-the-minute techni

  7. Water Column Variability in Coastal Regions

    Science.gov (United States)

    2016-06-07

    offshore waters of energy, mass, and biota. OBJECTIVES Our objective is to determine the processes that cause water column variations in coastal regions...meteorological conditions (solar radiation, wind velocity, and heat fluxes), (iv) tidal mixing, stratification, water mass variations, (v) runoff from land...air-sea gas exchange and biological activity in these offshore waters. Two papers are being submitted to Limnology and Oceanography on the annual

  8. COLLISIONS OF ROAD VEHICLES WITH BRIDGE COLUMNS

    OpenAIRE

    2015-01-01

    As speed limits and traffic on city roads continue to increase, collisions between road vehicles and bridge columns are becoming more common. Current regulations analyze collision with one major simplification: replacing dynamic action with the equivalent static force. In the present paper, we develop a numerical model of a typical Croatian overpass and loaded it with an equivalent static load according to the EN1991-7 and ASSHTO LRFD provisions, analyzing the differences in overpass behavior...

  9. Using Dividing Wall Columns (DWC) in LNG Production: deviding wall column, double dividing wall column, prefractionator arrangement, Petlyuk column, NGL recovery, distillation

    OpenAIRE

    Ashrafian, Roohollah

    2014-01-01

    The Dividing Wall Columns (DWC) distillation has attracted growing interest for fractionation of multicomponent mixture due to reduction of energy consumption, auxiliary equipment and space within fractionation process. Recent developments of the process show considerable energy saving, up to 30%-40%, compared to conventional fractionation schemes. The objective of this thesis is to introduce DWC configurations, governing equations and applications in LNG and gas processing as well as explana...

  10. [Cervical vertebral column--anatomy, fractures, treatment].

    Science.gov (United States)

    Kłosiński, Michał; Sienkiewicz-Zawilińska, Justyna; Lipski, Marcin; Zawiliński, Jarosław; Matyja, Andrzej; Walocha, Jerzy

    2009-01-01

    The paper deals with anatomy of human cervical spine. It shows close relation between knowledge on the normal structure and methods of treatment of different kinds of spine injuries. It describes detailed anatomy and mechanical features of cervical vertebral column, including the structure of distinct vertebrae, their joints and arrangement of muscles. It reviews also historical methods of treatment of fractures in this region considering current methods.

  11. SVD row or column symmetric matrix

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new architecture for row or column symmetric matrix called extended matrix is defined, and a precise correspondence of the singular values and singular vectors between the extended matrix and its original (namely, the mother matrix) is derived. As an illustration of potential, we show that, for a class of extended matrices, the singular value decomposition using the mother matrix rather than the extended matrix per se can save the CPU time and memory without loss of numerical precision.

  12. 2169 steel waveform experiments.

    Energy Technology Data Exchange (ETDEWEB)

    Furnish, Michael David; Alexander, C. Scott; Reinhart, William Dodd; Brown, Justin L.

    2012-11-01

    In support of LLNL efforts to develop multiscale models of a variety of materials, we have performed a set of eight gas gun impact experiments on 2169 steel (21% Cr, 6% Ni, 9% Mn, balance predominantly Fe). These experiments provided carefully controlled shock, reshock and release velocimetry data, with initial shock stresses ranging from 10 to 50 GPa (particle velocities from 0.25 to 1.05 km/s). Both windowed and free-surface measurements were included in this experiment set to increase the utility of the data set, as were samples ranging in thickness from 1 to 5 mm. Target physical phenomena included the elastic/plastic transition (Hugoniot elastic limit), the Hugoniot, any phase transition phenomena, and the release path (windowed and free-surface). The Hugoniot was found to be nearly linear, with no indications of the Fe phase transition. Releases were non-hysteretic, and relatively consistent between 3- and 5-mmthick samples (the 3 mm samples giving slightly lower wavespeeds on release). Reshock tests with explosively welded impactors produced clean results; those with glue bonds showed transient releases prior to the arrival of the reshock, reducing their usefulness for deriving strength information. The free-surface samples, which were steps on a single piece of steel, showed lower wavespeeds for thin (1 mm) samples than for thicker (2 or 4 mm) samples. A configuration used for the last three shots allows release information to be determined from these free surface samples. The sample strength appears to increase with stress from ~1 GPa to ~ 3 GPa over this range, consistent with other recent work but about 40% above the Steinberg model.

  13. Plant practices in fine coal column flotation

    Energy Technology Data Exchange (ETDEWEB)

    Davis, V.L. Jr.; Bethell, P.J.; Stanley, F.L. [Pittston Coal Management Co., Lebanon, VA (United States); Luttrell, G.H. [Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States). Dept. of Mining and Minerals Engineering

    1995-10-01

    Five 3 m (10 ft) diameter Microcel{trademark} flotation columns were installed at Clinchfield Coal Company`s Middle Fork preparation facility in order to reduce product ash and increase recovery and plant capacity. The Middle Fork facility is utilized for the recovery of fine coal from a feed stream that consists primarily of 1.5 mm x 0 material. The columns replaced conventional flotation cells for the treatment of the minus 150 {micro}m fraction while spirals are used to upgrade the plus 150 {micro}m material in the plant feed. The addition of the column flotation circuit resulted in an increase in plant capacity in excess of 20 percent while reducing the flotation product ash content by approximately 7 percentage points. Flotation circuit combustible recovery wa increased by 17 percentage points. This paper discusses circuit design, commissioning, and sparging system design. Circuit instrumentation, level control, reagent system control, performance comparisons with conventional flotation, and general operating procedures are also discussed.

  14. Seepage characteristics of collapse column fillings

    Institute of Scientific and Technical Information of China (English)

    Zhang Boyang; Bai Haibo; Zhang Kai

    2016-01-01

    With concealment and hysteresis, water-inrush from Karst collapse column has become an important security hazard of lower group coal mining in North China. Based on the MTS815.02 seepage test system, we analyzed the impact of consolidation pressure, initial moisture content and confining pressure on the permeability of fillings in order to study the seepage characteristics of collapse column fillings. The results show that:(1) The permeability of collapse column fillings is of the order of 10?16–10?15 magni-tude and decreases with an increase in consolidation pressure and decrease in initial moisture content. (2) The essence of filling seepage law change is the change in porosity, and a power function relationship exists between the permeability ratio and porosity ratio. (3) With increasing confining pressure, the per-meability of fillings decreases. However, under low confining pressure (1.2–4 MPa), the change of confin-ing pressure has no obvious influence on the permeability.

  15. SPEEDUP{trademark} ion exchange column model

    Energy Technology Data Exchange (ETDEWEB)

    Hang, T.

    2000-03-06

    A transient model to describe the pr