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Sample records for box girder bridges

  1. Stress and noises of steel box girders in Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Xue Tao; Chen Zhijian; Dong Xuewu

    2008-01-01

    Sutong Bridge is a cable-stayed bridge with a main span of 1 088 m.370 high-precision stress monitoring measured data show that in the process of hoisting the steel box girders,the stress of the main girders is in the fluctuant and complex state and many meteorological factors,such as sunshine radiation,temperature and wind,have important influence on the change of stress of the steel box girders.According to the real-time weather data,the stress data after the process of wavelet denoising from representative measuring points in different weather conditions is picked to estab-lish the stress response brought by meteorological factors with Layered Separation method,thereby basically eliminating the influence of meteorological factors on the stress of main girders,so that accurate and reliable stress data can be got for steel box girders adjustment and cable-tensioned construction control.

  2. Seismic response of skewed RC box-girder bridges

    Institute of Scientific and Technical Information of China (English)

    Ahmed Abdel-Mohti; Gokhan Pekcan

    2008-01-01

    It is critical to ensure the functionality of highway bridges after earthquakes to provide access to important facilities.Since the 1971 San Fernando earthquake,there has been a better understanding of the seismic performance of bridges.Nonetheless,there are no detailed guidelines addressing the performance of skewed highway bridges.Several parameters affect the response of skewed highway bridges under both service and seismic loads which makes their behavior complex.Therefore,there is a need for more research to study the effect of skew angle and other related factors on the performance of highway bridges.This paper examines the seismic performance of a three-span continuous concrete box girder bridge with skew angles from 0 to 60 degrees,analytically.Finite element (FE) and simplified beam-stick (BS) models of the bridge were developed using SAP2000.Different types of analysis were considered on both models such as:nonlinear static pushover,and linear and nonlinear time history analyses.A comparison was conducted between FE and BS,different skew angles,abutment support conditions,and time history and pushover analysis.It is shown that the BS model has the capability to capture the coupling due to skew and the significant modes for moderate skew angles.Boundary conditions and pushover load profile are determined to have a major effect on pushover analysis.Pushover analysis may be used to predict the maximum deformation and hinge formation adequately.

  3. Dynamic Analysis of Horizontally Curved Thin-Walled Box-Girder Bridge due to Moving Vehicle

    Directory of Open Access Journals (Sweden)

    K. Nallasivam

    2007-01-01

    Full Text Available The impact on curved box-girder bridges due to vehicle moving across rough bridge deck have been analyzed using bridge-vehicle coupled dynamics. The bridge deck unevenness has been assumed to be a homogeneous random process in space specified by a PSD function. The analysis incorporates the effect of centrifugal forces due to vehicle moving on curved bridge. The curved box-girder bridge has been numerically modeled using computationally efficient thin-walled box-beam finite elements which take into account the torsional warping, distortion and distortional warping, that are important features of thin-walled box girders. Rigid vehicle with longitudinal and transverse input to the wheels giving rise to heave-pitch-roll degrees of freedom has been considered. The theoretical bridge model used in simulation study has been validated by a free vibration experiment using impact excitation. The impact factors for several response parameters such as bending moment, shear force, torsional moment, torsional bi-moment, distortional moment, distortional bi-moment and vertical deflections have been obtained for various bridge-vehicle parameters. Both constant velocity and forward acceleration of the vehicle have been considered to examine impact factor. The results highlighted that the impact factors of a curved box girder bridge corresponding to torsion, distortion and their corresponding bimoments have been observed to be generally very high, while those of the other responses are also relatively higher than that of corresponding straight box girder bridge.

  4. Research on the special lifting devices for steel box girders of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Chen Ming; Wu Qihe; Luo Chengbin; Zhou Hanfa

    2009-01-01

    Sutong Bridge is a cable-stayed bridge with a steel box girder and a main span of 1 088 m. The steel box girder of main span includes five portions: back span large unit, large block of pylon, standard girder, back span closure girder and middle span closure girder. Each back span large unit is fabricated by welding several deck segments together in factory, and is erected by floating crane. As navigational clearance of the main bridge is high, the traditional truss lifting device can' t satisfy the requirement of domestic lifting cranes for this kind of lifting height and weight. Hence, a kind of lighter lifting device for the erection of back span large units was accepted for this bridge. In this paper, the design and use of this lifting device is introduced.The upper structure used lifting gantry to install the standard girder segment by cantilever method. Because the bridge's navigation clearance is high, and the girder segment is wide and heavy, the meteorology and hydrology condition of the bridge district is abominable, and the requirements of long cable girder side pull-in, structure and performance propose high request to the lifting gantry. In this paper, the design and use key point of long cable pull-in angle adjustment device integrate into lifting gantry is introduced.

  5. Effect of material uncertainties on dynamic response of segmental box girder bridge

    Directory of Open Access Journals (Sweden)

    Suchart Limkatanyu

    2007-11-01

    Full Text Available The main objective of this paper was to investigate the effect of material uncertainties on dynamic response of segmental box girder bridge subjected to a moving load, in this case a rapid passing trains. Literatures concerned with the design of segmental box girder bridge, the application of finite element analysis to model the segmental box girder bridge, and the minimum requirement for structural conditions of the bridge were described and discussed in detail. A series of finite element analysis was carried out using SAP2000 Nonlinear software. The effect was investigated by varying the Modulus of Elasticity by 5%, 10% and 15%. The results were then compared with the case of assumed uniform property which had already been checked for model accuracy using the Standard prEN 1991-2. The results showed that, for the uniform case, the dynamic responses of the bridge gave the highest response at the resonance speed. When considering the non-uniform material properties (non-uniform case, the effect of material uncertainties appeared to have an effect on both displacement and acceleration responses. Nonetheless, the dynamic factor provided in the design code was sufficient for designing the segmental box girder bridge with either uniform or non-uniform material properties for the train speeds considered in this study.

  6. Computer Simulation of Dynamic Interactions Between Vehicle and Long Span Box Girder Bridges

    Institute of Scientific and Technical Information of China (English)

    Lei Gong; Moe S.Cheung

    2008-01-01

    Moving vehicle loads,associated with roadway traffic can induce significant dynamic effects on the structural behaviours of bridges,especially for long-span bridges.The main objective of current research is to study traffic induced dynamic responses of long-span box-girder bridges.The finite element method has been employed in this study to obtain a three-dimensional mathematical model for the bridge system.For vehicle-bridge dynamic interaction analysis,the vehicle is modeled as a more realistic three-axle,six-wheel system,and the corresponding dynamic interaction equations have been derived.The bridge-vehicle inter- action is affected by many factors.The current study has been focused on such factors as:vehicle speed, vehicle damping ratio,multiple traffic lanes,mass ratio of vehicle and bridge,and dynamic characteristics of bridge.Case studies have been conducted to investigate these factors by using several box girder bridge examples including Confederation Bridge,the longest box girder bridge in the world.

  7. Field test on temperature field and thermal stress for prestressed concrete box-girder bridge

    Institute of Scientific and Technical Information of China (English)

    Baoguo CHEN; Rui DING; Junjie ZHENG; Shibiao ZHANG

    2009-01-01

    A field test was conducted to investigate the distribution of temperature field and the variation of thermal stress for a prestressed concrete (PC) box-girder bridge. The change of hydration heat temperature consists of four periods: temperature rising period, constant temperature period, rapid temperature fall period and stow temperature fall period. The peak value of hydration heat temperature increases with the increasing casting temperature of concrete; the relation between them is approximately linear. According to field tests, the thermal stress incurred by hydration heat may induce temperature cracks on the PC box-girder. Furthermore, the nonlinear distribution of temperature gradient and the fluctuation of thermal stress induced by exposure to sunlight were also obtained based on continuous in-situ monitoring. Such results show that the prevailing Chinese Code (2004) is insufficient since it does not take into account the temperature gradient of the bottom slab. Finally, some preventive measures against temperature cracks were proposed based on related studies. The conclusions can provide valuable reference for the design and construction of PC box-girder bridges.

  8. Free vibrations of multi-girder and multi-cell box bridges with transverse deformations effects

    Science.gov (United States)

    Hamed, E.; Frostig, Y.

    2005-01-01

    A general mathematical approach is developed for the free vibration behaviour analysis of multi-girder and multi-cell box bridges with a single or multi span, including the effects of the transverse deformations of the bridge cross-section. The governing equations of motion and the corresponding boundary and continuity conditions are derived via the variational principle of virtual work following Hamilton's principle. The model is general and valid for any boundary and continuity conditions, and is applicable for multi-girder bridges with longitudinal and cross beams and for multi-cell box bridges. The warping and the distortion of the bridge cross-section effects are included in the proposed model. Closed-form solutions of the governing equations are derived and the Newton-Raphson method is used to determine the eigenfrequencies. Numerical examples are presented to validate the proposed model, and are also used to examine the accuracy of other approximate models used in the analysis of bridges. The results of the proposed model are validated through comparison with three-dimensional finite element models. The results reveal that the transverse deformations decrease the magnitudes of the eigenfrequencies of the torsional mode shapes, as well as the high flexural modes.

  9. Fatigue stress monitoring and analyses for steel box girder of Runyang Suspension Bridge

    Institute of Scientific and Technical Information of China (English)

    Ying WANG; Zhaoxia LI; Baijian WU

    2008-01-01

    The monitoring of fatigue stress of steel bridge is a key issue of bridge health monitoring and safety assessment. This paper aims to find out the strain history features of the girder components of Runyang Suspension Bridge (RYSB) under vehicle and environmental loading during its first year of service based on the strain-history data recorded by structural health monitoring system installed in the bridge. The fatigue stress spectrums of steel box girders under normal traffic load, heavy trucks and typhoon loads were studied as well as the correlation between varying strain and temperature based on real-time monitoring of temperature histories. The results show that, monitoring on local strain in health monitoring systems of RYSB can effectively provide the information on fatigue stresses. The range of the equivalent fatigue stress on the monitoring location of the bridge is currently low, mainly due to varying traffic loading and temper-ature. There exists significant correlation between varying temperature and mean value of fatigue stress. Effect of the passing of heavy trucks on bridge fatigue is quite signifi-cant since the value of the cumulative fatigue damage generated by heavy trucks is 10 to 100 times larger than that by normal traffic. Therefore, the effect on fatigue cumulative damage due to heavy trucks or overloaded vehicles needs to be monitored and paid much attention to.

  10. Spatial Finite Element Analysis for Dynamic Response of Curved Thin-Walled Box Girder Bridges

    Directory of Open Access Journals (Sweden)

    Yinhui Wang

    2016-01-01

    Full Text Available According to the flexural and torsional characteristics of curved thin-walled box girder with the effect of initial curvature, 7 basic displacements of curved box girder are determined. And then the strain-displacement calculation correlations were established. Under the curvilinear coordinate system, a three-noded curved girder finite element which has 7 degrees of freedom per node for the vibration characteristic and dynamic response analysis of curved box girder is constructed. The shape functions are used as the interpolation functions of variable curvature and variable height to accommodate to the variation of curvature and section height. A MATLAB numerical analysis program has been implemented.

  11. Dynamic finite element model updating of prestressed concrete continuous box-girder bridge

    Institute of Scientific and Technical Information of China (English)

    Lin Xiankun; Zhang Lingmi; Guo Qintao; Zhang Yufeng

    2009-01-01

    The dynamic finite element model (FEM) of a prestressed concrete continuous box-girder bridge, called the Tongyang Canal Bridge, is built and updated based on the results of ambient vibration testing (AVT) using a real-coded accelerating genetic algorithm (RAGA). The objective functions are defined based on natural frequency and modal assurance criterion (MAC) metrics to evaluate the updated FEM. Two objective functions are defined to fully account for the relative errors and standard deviations of the natural frequencies and MAC between the AVT results and the updated FEM predictions. The dynamically updated FEM of the bridge can better represent its structural dynamics and serve as a baseline in long-term health monitoring, condition assessment and damage identification over the service life of the bridge.

  12. Research on overall assembling and welding process of steel box girder tuyere blocks of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Yan Shiguang; Li Hongtao; Wang Chao

    2012-01-01

    This article presents in detail the assembling and welding process technique of the steel box girder tuyere blocks of Taizhou Bridge. The application of this process technique effectively solves the problem of welding stress release in tuyere block assembling and welding without increasing the number of turns of the blocks and overhead welding, thus avoiding possible structural deformation due to excessive accumulation of internal welding stress, greatly reducing the repeated deformation and correction work during assembling and welding, and ensuring the weld seam quality and overall dimensions of tuvere blocks of Taizhou Bridze.

  13. Finite element model updating of a prestressed concrete box girder bridge using subproblem approximation

    Science.gov (United States)

    Chen, G. W.; Omenzetter, P.

    2016-04-01

    This paper presents the implementation of an updating procedure for the finite element model (FEM) of a prestressed concrete continuous box-girder highway off-ramp bridge. Ambient vibration testing was conducted to excite the bridge, assisted by linear chirp sweepings induced by two small electrodynamic shakes deployed to enhance the excitation levels, since the bridge was closed to traffic. The data-driven stochastic subspace identification method was executed to recover the modal properties from measurement data. An initial FEM was developed and correlation between the experimental modal results and their analytical counterparts was studied. Modelling of the pier and abutment bearings was carefully adjusted to reflect the real operational conditions of the bridge. The subproblem approximation method was subsequently utilized to automatically update the FEM. For this purpose, the influences of bearing stiffness, and mass density and Young's modulus of materials were examined as uncertain parameters using sensitivity analysis. The updating objective function was defined based on a summation of squared values of relative errors of natural frequencies between the FEM and experimentation. All the identified modes were used as the target responses with the purpose of putting more constrains for the optimization process and decreasing the number of potentially feasible combinations for parameter changes. The updated FEM of the bridge was able to produce sufficient improvements in natural frequencies in most modes of interest, and can serve for a more precise dynamic response prediction or future investigation of the bridge health.

  14. Life-Cycle Monitoring of Long-Span PSC Box Girder Bridges through Distributed Sensor Network: Strategies, Methods, and Applications

    Directory of Open Access Journals (Sweden)

    Zheheng Chen

    2015-01-01

    Full Text Available Structural health monitoring (SHM has attracted much attention in recent years, which enables early warnings of structural failure, condition assessments, and rational maintenance/repair strategies. In the context of bridges, many long-span steel bridges in China have been installed with the SHM systems; however, the applications of the SHM in prestressed concrete (PSC bridges are still rather limited. On the other hand, the PSC box girder bridges are extensively used in highway and railway systems and premature damage of these bridges is often reported, resulting in considerable maintenance and/or replacement costs. First, this paper presents a state-of-art review on the SHM of long-span PSC bridges. Monitoring strategies, methods, and previous applications for these bridges are summarized and discussed. In order to well capture the behavior of the bridge during its whole life and to maximize the use of sensors, a life-cycle monitoring strategy is proposed, in which the sensor layout is determined according to requirements for construction monitoring, completion test, and in-service monitoring. A case study is made on a three-span PSC box girder bridge in China. The system configuration, sensor layout, and data communications, and so forth, are presented. The up-to-date monitored structural responses are analyzed and compared with the design values.

  15. Development of the applicability of simplified Henry's method for skewed multicell box-girder bridges under traffic loading conditions

    Institute of Scientific and Technical Information of China (English)

    Iman MOHSENI; A.R.Khalim RASHID

    2012-01-01

    Concrete precast multicell box-girder (MCB) bridges combine aesthetics with torsional stiffness perfectly.Previous analytical studies indicate that currently available specifications are unable to consider the effect of the twisting moment (torsional moment) on bridge actions.In straight bridges the effect of torsion is negligible and the transverse reinforced design is governed by other requirements.However,in the case of skewed bridges the effect of the twisting moment should be considered.Therefore,an in-depth study was performed on 90 concrete MCB bridges with skew angles ranging from 0° to 60°.For each girder the bridge actions were determined under the American Association of State Highway and Transportation Officials (AASHTO) live load conditions.The analytical results show that torsional stiffness and live load positions greatly affected the bridges' responses.In addition,based on a statistical analysis of the obtained results,several skew correction factors are proposed to improve the precision of the simplified Henry's method,which is widely used by bridge engineers to predict bridge actions.The relationship between the bending moment and secondary moments was also investigated and it was concluded that all secondary actions increase with an increase in skewness.

  16. Behavior of horizontally curved steel tubular-flange bridge girders

    Science.gov (United States)

    Fan, Zhuo

    A new type of curved steel bridge girder, called a curved tubular-flange girder, with rectangular tubes as flanges, is proposed and studied in this dissertation. A curved steel tubular-flange girder has much larger torsional stiffness than a curved I-girder and less potential for cross section distortion than a curved box-girder. Therefore, it has potential advantages compared to curved I-girders and box-girders. A theoretical analysis method for systems of curved tubular-flange girders braced by cross frames is presented. A stress analysis method for tubular-flange girders is also provided. The behavior of curved tubular-flange girder systems is studied using the theoretical analysis method and compared to the behavior of the corresponding curved I-girder systems. A parametric study is performed using the theoretical analysis method to investigate the effects of geometric parameters on the behavior of curved tubular-flange girder systems. The studied parameters include tubular-flange width, tubular-flange depth, cross section depth, girder curvature, and the number of cross frames. Finite element analyses are conducted to verify the theoretical analysis method, to study the behavior of a curved tubular-flange girder system under dead load, and to study the behavior of a curved tubular-flange girder system with a composite concrete deck under dead and live load. The study shows that a curved tubular-flange girder system develops much less warping normal stress and cross section rotation than a corresponding curved I-girder system. The difference is especially significant for a single curved girder under its own weight, suggesting that curved tubular-flange girders would be much easier to transport and erect than curved I-girders. As girder curvature increases, the rate of increase in the stresses and displacements for a single I-girder is much greater than for a single curved tubular-flange girder. Smaller cross frame forces develop in a tubular-flange girder

  17. Long-term monitoring of a PSC box girder bridge: Operational modal analysis, data normalization and structural modification assessment

    Science.gov (United States)

    Cury, Alexandre; Cremona, Christian; Dumoulin, John

    2012-11-01

    For reliable performance of vibration-based damage detection algorithms, it is important to distinguish abnormal changes in modal parameters caused by structural damage from normal changes due to environmental fluctuations. This paper firstly addresses the modeling of temperature effects on modal frequencies of a PSC box girder bridge located on the A1 motorway in France. Based on a six-month monitoring experimental program, modal frequencies of the first seven mode shapes and temperatures have been measured at three hour intervals. Neural networks are then introduced to formulate regression models for quantifying the effect of temperature on modal parameters (frequencies and mode shapes). In 2009, this bridge underwent a strengthening procedure. In order to assess the effect of strengthening on the vibration characteristics of the bridge, modal properties had to be corrected from temperature influence. Thus, the first goal is to assess the changes on the vibration signature of this bridge induced by the strengthening. For this purpose, classical statistical analysis and clustering methods are applied to the data recorded over the period after strengthening. The second goal is to evaluate the influence of temperature effects on the clustering results. It comes that the temperature correction significantly improves the confidence in the novelty detection and in the strengthening efficiency.

  18. Structural health monitoring of an existing PC box girder bridge with distributed HCFRP sensors in a destructive test

    Science.gov (United States)

    Yang, Caiqian; Wu, Zhishen; Zhang, Yufeng

    2008-06-01

    The application of hybrid carbon fiber reinforced polymer (HCFRP) sensors was addressed to monitor the structural health of an existing prestressed concrete (PC) box girder bridge in a destructive test. The novel HCFRP sensors were fabricated with three types of carbon tows in order to realize distributed and broad-based sensing, which is characterized by long-gauge length and low cost. The HCFRP sensors were bonded on the bottom and side surfaces of the existing bridge to monitor its structural health. The gauge lengths of the sensors bonded on the bottom and side surfaces were 1.5 m and 1.0 m, respectively. The HCFRP sensors were distributed on the bridge for two purposes. One was to detect damage and monitor the structural health of the bridge, such as the initiation and propagation of new cracks, strain distribution and yielding of steel reinforcements. The other purpose was to monitor the propagation of existing cracks. The good relationship between the change in electrical resistance and load indicates that the HCFRP sensors can provide actual infrastructures with a distributed damage detection and structural health monitoring system. Corrections were made to this article on 13 May 2008. The corrected electronic version is identical to the print version.

  19. Acoustic Emission Monitoring of Multicell Reinforced Concrete Box Girders Subjected to Torsion

    OpenAIRE

    Marya Bagherifaez; Arash Behnia; Abeer Aqeel Majeed; Chai Hwa Kian

    2014-01-01

    Reinforced concrete (RC) box girders are a common structural member for road bridges in modern construction. The hollow cross-section of a box girder is ideal in carrying eccentric loads or torques introduced by skew supports. This study employed acoustic emission (AE) monitoring on multicell RC box girder specimens subjected to laboratory-based torsion loading. Three multicell box girder specimens with different cross-sections were tested. The aim is to acquire AE analysis data indicative fo...

  20. Comparison of Temperature Loadings of Bridge Girders

    Directory of Open Access Journals (Sweden)

    J. Římal

    2008-01-01

    Full Text Available This paper compares the effect of temperature changes on the superstructure of bridges, above all the effect of non-uniform temperature. Loadings according to standards ESN 73 6203, ENV 1991-1-5 and DIN 1072 are compared here. The paper shows a short summary of temperature loading according to each standard and shows the comparison of bending moments arisen from these temperature loadings on superstructure made from continuous girder from a steel-concrete box girder with a composite concrete slab. With respect to a variety of design processes, the comparison is made without any coefficient of loading, combination or material. 

  1. 桥面铺装与小箱梁的共同作用试验%Experiment of Coaction of Bridge Deck Pavement and Small Box Girder

    Institute of Scientific and Technical Information of China (English)

    钱寅泉; 周正茂; 袁桂芳; 王素娟

    2012-01-01

    Load tests on a single small box girder and a bridge were carried out to evaluate the effects of deck pavement by comparing the deflections of the girders before and after the pavement surfaced. The comprehensive elastic modulus was obtained from the test before pavement surfaced, and the coaction degree of the bridge deck pavement and the girders was obtained by comparing the flexural inertia moment corresponding to the deflection in the test after pavement surfaced with the theoretical flexural inertia moment corresponding to the supposed thickness of the pavement in work. The results from these tests show that (1) the rough interface could greatly improve the coaction degree of bridge deck pavement with girders, which could reach 100% ; (2) in general cases, the extent of the coaction of bridge deck pavement with girders could reach 70% , and for a pavement with thickness of 8 cm, the thickness of the pavement in coaction could be taken as 60% or 3 cm in thickness could be substracted from the pavement in design; (3 ) the pavement could improve the uniformity of the transverse load distribution. Load tests on a single small box girder and a bridge were carried out to evaluate the effects of deck pavement by comparing the deflections of the girders before and after the pavement surfaced. The comprehensive elastic modulus was obtained from the test before pavement surfaced, and the coaction degree of the bridge deck pavement and the girders was obtained by comparing the flexural inertia moment corresponding to the deflection in the test after pavement surfaced with the theoretical flexural inertia moment corresponding to the supposed thickness of the pavement in work. The results from these tests show that (1) the rough interface could greatly improve the coaction degree of bridge deck pavement with girders, which could reach 100% ; (2) in general cases, the extent of the coaction of bridge deck pavement with girders could reach 70% , and for a pavement with

  2. 跨多股道钢箱梁天桥的结构设计%The Structural Design of Steel Box Girder Pedestrian Bridge Crossing Multiple Railways

    Institute of Scientific and Technical Information of China (English)

    沈耀海

    2011-01-01

    结合西部某新建火车站进站人行天桥工程实例,分析了设计和施工的多种控制条件,论证了主梁采用钢箱梁结构的合理性.通过有限元分析和动力特性计算可知,结构设计的控制因素为竖向自振频率,采用中墩与主梁固结的连接方式可以有效地调整结构竖向自振频率.%Based on the project case of one pedestrian bridge in one new constructed railway station at west China, many controlled conditions are analyzed about structural design and engineering construction, and the rationalitles of steel box girder bridge adopted in the design are also demonstrated. It is learned from finite - element analysis and dynamic characteristics calculation that the control factor of structural design is vertical vibration frequency, which can be improved effectively by means of fixed connection between central pier and steel box girder.

  3. Design of Norway HAKRDANGER Steel Box Girder Bridge Coating Process%挪威HAKRDANGER大桥钢箱梁涂装工艺设计

    Institute of Scientific and Technical Information of China (English)

    李连缀; 李敏风

    2011-01-01

    The anti-corrosion matching scheme and performance of the Norwegian HAKRDANGER bridge steel box girder inside and outside were introduced. The design of coating process including surface treatment, arc spraying zinc process, spray construction process equipment and related technical parameters requirements were introduced in detail.%介绍了挪威HAKRDANGER大桥钢箱梁内外侧防腐配套方案及性能。着重介绍了涂装工艺设计,包括表面处理、电弧喷锌工艺、喷漆施工等工艺设备及相关技术参数要求等。

  4. Aerodynamic stability study of a long-span prestressed concrete cable-stayed bridge. Aerodynamic behavior of edge box girder under uniform flow; Chodai PC shachokyo no taifu anteisei ni kansuru kenkyu. Ichiyoryuchu ni okeru edge girder keishiki no kuriki tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, T. [Obayashi Corp., Tokyo (Japan)

    1999-01-10

    In recent years, the construction of long-span bridges is on the increase. Prestressed concrete cable-stayed bridges are dynamically very efficient structures of relatively low cost that blend in well with the landscape. Maintenance is also easy. Consequently, the adoption of edge box girders for cable-stayed bridges is increasing worldwide, but problems related to the aerodynamic stability of the structure have emerged. The aerodynamic stability of edge box girders for a prestressed concrete cable-stayed bridge was investigated under uniform flow conditions by conducting several wind tunnel experiments. As a result, the section of the bridge deck was optimized to prevent torsional flutter within an angle of attack varying from -5 to +5 degrees. It is therefore possible to guarantee the aerodynamic stability of long-span prestressed concrete cable-stayed bridges. (author)

  5. A case study of interior low-frequency noise from box-shaped bridge girders induced by running trains: Its mechanism, prediction and countermeasures

    Science.gov (United States)

    Zhang, Xun; Li, Xiaozhen; Hao, Hong; Wang, Dangxiong; Li, Yadong

    2016-04-01

    A side effect of high-speed railway and urban rail transit systems is the associated vibration and noise. Since the use of concrete viaducts is predominant in railway construction due to scarce land resources, low-frequency (20-200 Hz) structure-radiated noise from concrete bridges is a principal concern. Although it is the most commonly used bridge type, the mechanism of noise emission from box-shaped bridge girders when subjected to impact forces from moving trains, which sounds like beating a drum, has not been well studied. In this study, a field measurement was first made on a simply-supported box-shaped bridge to record the acceleration of the slabs and the associated sound pressures induced by running trains. These data indicated that a significant beat-wave noise occurred in the box-shaped cavity when the train speed was around 340 km/h, which arose from the interference between two sound waves of 75.0 Hz and 78.8 Hz. The noise leakage from the bridge expansion joint was serious and resulted in obvious noise pollution near the bridge once the beat-wave noise was generated in the cavity. The dominant frequency of the interior noise at 75.0 Hz was confirmed from the spectrum of the data and the modal analysis results, and originated from the peak vibration of the top slab due to resonance and the first-order vertical acoustic mode, which led to cavity resonance, amplifying the corresponding noise. The three-dimensional acoustic modes and local vibration modes of the slab were calculated by using the finite element method. A simplified vehicle-track-bridge coupling vibration model was then developed to calculate the wheel-rail interaction force in a frequency range of 20-200 Hz. Numerical simulations using the boundary element method confirmed the cavity resonance effect and the numerical results agreed well with the data. Based on the calibrated numerical model, three noise reduction measures, i.e., adding a horizontal baffle in the interior cavity, narrowing

  6. Experimental Modal Anlysis of Pedestrian Steel Box Girder Bridge%人行钢箱梁桥模态试验研究

    Institute of Scientific and Technical Information of China (English)

    申杨凡; 杨斌; 何钰龙; 郭凯强; 续琦峰; 王艳琪; 贾艳敏

    2016-01-01

    为了了解人行钢桥的自振特性,运用东华测试系统对某人行钢箱梁桥进行模态测试,得到桥梁的动力特性参数,并将试验测得的固有频率、模态振型与 ANSYS 有限元模型中的模态数据进行对比分析。分析结果表明:该人行钢箱梁桥的基频的试验值与理论值的误差为3.8%,行人的附加模态质量是对试验产生误差的原因之一,但对结构基频的影响不大,这也就证明了采用峰值拾取法处理时域数据是合理的,同时结合模态判定准则所得模态数据也是可信的,通过该模态测试系统可有效地测得模态参数(固有频率、模态振型及阻尼比)。%In order to study the natural vibration characteristics of the pedestrian bridge steel,a pedestrian steel box girder bridge’s model experiment is carried out with Donghua Test System to get the dynamic characteristics of bridge,and comparing Natural frequency and mode shapes with modal data a-nalysis of ANSYS finite element model.The analysis results indicate that the error between the fundamen-tal frequency experiment value and the theoretical value of the pedestrian steel box girder bridge is 3.8%.And the additional modal mass of pedestrian is one of the reasons why the experiment have error,it’s in-fluence is little.What proved that using the Peak Picking Method to manipulation time domain data is rea-sonable.At the same time,the modal date that obtained by combining with the modal criterion is credi-ble.That modal parameters(natural frequency,modal vibration mode and damping ratio)can be measured effectively by the modal testing system.

  7. Design plan and checking calculation for the reinforcement of prestressed continuous box girder bridges%预应力连续箱梁桥加固设计及验算

    Institute of Scientific and Technical Information of China (English)

    张胜

    2016-01-01

    某预应力连续箱梁桥运营15年后,箱梁内外出现了较多的裂缝、钢筋锈蚀和台后填土沉降等病害,已影响桥梁结构的正常使用和安全。根据该桥的质量检测报告,提出了箱梁顶板采用增厚钢筋混凝土、箱室顶板内表面采用粘贴钢板和碳纤维相结合以及箱梁腹板粘贴钢板的加固方法。通过理论计算和荷载试验对加固后的桥梁承载力进行了验算和检测,结果表明,结构承载力和刚度都有明显地提高,能保证桥梁的正常使用。%A prestressed continuous box girder bridge appeared various diseases in fifteen years, for instance, cracks of the inside and outside surface of the box girder, steel corrosion and the obvious settlement of filling at back abutment. The disease has affected the normal use and safety of the bridge structure. Based on the testing reports of the bridge, a feasible strengthening method is put forward: The roof of box girder is strengthened by the thick reinforced concrete;The top plate of the box is strengthened by steel plate and carbon fiber, and box girder webs is strengthened by steel plate. The carrying capacity of the reinforced bridge is checked by the theoretical calculation and the load test. The results show that the bearing capacity and stiffness of the structure are obviously improved and can meet the requirements of normal use.

  8. Pedestrian bridge steel box girder with steel truss mechanics performance comparison and analysis%钢箱梁与钢桁架人行天桥力学性能对比分析

    Institute of Scientific and Technical Information of China (English)

    申杨凡; 续琦峰; 杨斌; 王绍全; 郭凯强; 王艳琪; 贾艳敏

    2015-01-01

    为了分析并对比钢箱梁与钢桁架人行天桥的力学性能,建立了两者的ANSYS有限元计算模型,通过静力分析,得出钢桁架人行天桥的承载力更大,通过动力特性分析,钢桁架人行天桥较钢箱梁人行天桥更易产生扭转,且钢箱梁的自振频率较钢桁架的自振频率要大。%In order to analyze and contrast the steel box girder and steel truss pedestrian bridge mechanical properties,the ANSYS finite element calculation model is established,by static analysis,we can draw the steel truss of pedestrian bridge bearing capacity is larger,through the analy-sis of the dynamic characteristics of the pedestrian steel truss bridge with steel box girder footbridge reverse easier to be produced,and the natural frequency of vibration of the steel box girders for bigger than the natural frequency of vibration of steel truss.

  9. Unconventional Bearing Capacity Analysis and Optimization of Multicell Box Girders

    Directory of Open Access Journals (Sweden)

    Jovan Tepic

    2014-01-01

    Full Text Available This study deals with unconventional bearing capacity analysis and the procedure of optimizing a two-cell box girder. The generalized model which enables the local stress-strain analysis of multicell girders was developed based on the principle of cross-sectional decomposition. The applied methodology is verified using the experimental data (Djelosevic et al., 2012 for traditionally formed box girders. The qualitative and quantitative evaluation of results obtained for the two-cell box girder is realized based on comparative analysis using the finite element method (FEM and the ANSYS v12 software. The deflection function obtained by analytical and numerical methods was found consistent provided that the maximum deviation does not exceed 4%. Multicell box girders are rationally designed support structures characterized by much lower susceptibility of their cross-sectional elements to buckling and higher specific capacity than traditionally formed box girders. The developed local stress model is applied for optimizing the cross section of a two-cell box carrier. The author points to the advantages of implementing the model of local stresses in the optimization process and concludes that the technological reserve of bearing capacity amounts to 20% at the same girder weight and constant load conditions.

  10. 60 Meters Steel Box Girder Installation across Existing Railway with Bridge Machine Technique%采用架桥机进行跨既有铁路60m钢箱梁安装施工技术

    Institute of Scientific and Technical Information of China (English)

    郝晋新

    2012-01-01

    Taking Shanxi Pingyang freeway LJ26 contract section of Taiyuan hub K119 + 555 overpass bridge project as an example, for problems in large span steel box girder across existing railway construction, by comparison of the schemes pro- posed, and finally the paper selects the integral installation construction method of large span steel box girder with new bridge machine across the existing double railway electrification, and accordingly independent design and manufacture of a kind of YQXZ240t-60A3 bridge erecting machine is made. The paper introduces the composition of bridge erecting machine, and summarizes the keg construction process of the bridging machine for large span steel box beam erection construction.%以山西省平阳高速公路LJ26合同段太原枢纽K119+555跨线桥工程为例,针对大跨度钢箱梁跨既有铁路施工时遇到的难题,经方案比选,提出并最终采用新型架桥机进行上跨既有双线电气化铁路的大跨度钢箱梁的整体安装施工方法,并据此自主设计制造了一种YQXZ240t一60A3架桥机。介绍了架桥机的组成,总结了采用该架桥机进行大跨度钢箱梁架设施工的关键施工工艺。

  11. Current status of research on fatigue damage in steel box girder of cable-supported bridge in China%我国缆索支承桥梁钢箱梁疲劳损伤研究现状

    Institute of Scientific and Technical Information of China (English)

    吉伯海

    2014-01-01

    针对钢桥运营安全亟需关注的热点问题之一---缆索支承桥梁钢箱梁的安全性、耐久性,回顾我国钢箱梁疲劳损伤相关研究概况及主要成果,分析总结过去研究中存在的难点与热点问题,并对今后的发展方向提出了展望与建议。%The safety and durability of the steel box girder of cable-supported bridges has become a compelling subject in steel bridge safety operation. This paper provides a review on the research status and main results of fatigue damage in steel box girders in China, presents an analysis of the difficulties and pressing issues in previous research, and puts forward prospects and suggestions for the future development.

  12. Model Test of Continuous Composite Box Girder in Hong Kong-Zhuhai-Macao Bridge%港珠澳大桥组合连续箱梁模型试验研究

    Institute of Scientific and Technical Information of China (English)

    刘沐宇; 毛玉东; 邓晓光; 徐镜; 张强; 卢志芳

    2014-01-01

    A two-span composite continuous box girder (2 × 8.5 m) test model was designed based on the HZMB shallow water non-navigable bridge according to principle of similitude.Gradation loading test and finite element modeling were researched based on the actual construction process and operation load.The experimental results show that under 100% and 150% normal operation loads,the measured value of each key strain and deflection measure point in steel girder and concrete is linear,and the connection between the shear studs of cluster type and concrete slab is well.In addition,the unloading spring-back strain and deflection is small.In a word,for the high safety capacity and excellent structural overall performance,the continuous composite box girder bridge should be popularized and applied.%以港珠澳大桥组合连续箱梁为研究背景,基于相似原理设计制作了2×8.5m的钢-混组合连续箱梁试验模型.根据实桥施工过程和运营荷载,对试验模型开展分级加载试验和有限元模拟.结果表明:正常运营和150%运营荷载下,集束式剪力钉和混凝土板连接良好,钢箱梁、混凝土板应变和挠度呈线性增长,且卸载回弹良好,表明钢-混组合连续箱梁桥受力安全储备高,结构整体性能好,值得推广应用.

  13. Acoustic emission monitoring of multicell reinforced concrete box girders subjected to torsion.

    Science.gov (United States)

    Bagherifaez, Marya; Behnia, Arash; Majeed, Abeer Aqeel; Hwa Kian, Chai

    2014-01-01

    Reinforced concrete (RC) box girders are a common structural member for road bridges in modern construction. The hollow cross-section of a box girder is ideal in carrying eccentric loads or torques introduced by skew supports. This study employed acoustic emission (AE) monitoring on multicell RC box girder specimens subjected to laboratory-based torsion loading. Three multicell box girder specimens with different cross-sections were tested. The aim is to acquire AE analysis data indicative for characterizing torsion fracture in the box girders. It was demonstrated through appropriate parametric analysis that the AE technique could be utilized to effectively classify fracture developed in the specimens for describing their mechanical behavior under torsion. AE events localization was presented to illustrate the trend of crack and damage propagation in different stages of fracture. It could be observed that spiral-like patterns of crack were captured through AE damage localization system and damage was quantified successfully in different stages of fracture by using smoothed b-value analysis.

  14. Acoustic Emission Monitoring of Multicell Reinforced Concrete Box Girders Subjected to Torsion

    Directory of Open Access Journals (Sweden)

    Marya Bagherifaez

    2014-01-01

    Full Text Available Reinforced concrete (RC box girders are a common structural member for road bridges in modern construction. The hollow cross-section of a box girder is ideal in carrying eccentric loads or torques introduced by skew supports. This study employed acoustic emission (AE monitoring on multicell RC box girder specimens subjected to laboratory-based torsion loading. Three multicell box girder specimens with different cross-sections were tested. The aim is to acquire AE analysis data indicative for characterizing torsion fracture in the box girders. It was demonstrated through appropriate parametric analysis that the AE technique could be utilized to effectively classify fracture developed in the specimens for describing their mechanical behavior under torsion. AE events localization was presented to illustrate the trend of crack and damage propagation in different stages of fracture. It could be observed that spiral-like patterns of crack were captured through AE damage localization system and damage was quantified successfully in different stages of fracture by using smoothed b-value analysis.

  15. MTMDs控制高速铁路简支箱梁桥车致振动噪声的研究%Structure-borne noise control with MTMDs for a high-speed railway simply supported box-girder bridge

    Institute of Scientific and Technical Information of China (English)

    张迅; 李小珍; 刘全民; 张志俊; 李亚东

    2013-01-01

    轨道不平顺性激励引起桥梁结构振动,进而向空间辐射噪声.为了探明多重调谐质量阻尼器(MTMDs)对桥梁结构噪声的影响,选取32 m双线混凝土简支箱梁为研究对象,建立了移动集中力-桥梁-MTMDs耦合振动模型,根据桥梁的挠曲频响函数,求取了MTMDs的最优控制参数.在此基础上,采用瞬态有限元法和声学边界元法研究了不同数量调谐质量阻尼器对桥梁的减振、降噪效果.研究结果表明:MTMDs能有效控制桥梁的最大振动响应;由于MTMDs仅对一阶竖弯频率处的结构振动控制有效,使得其对结构噪声的控制效果不甚明显,对近轨侧25 m处声场的平均降噪效果约0.5 dB.%When a train runs across a bridge,the bridge is excited by dynamic forces acting on it because of the track irregularities,and the structure-borne noise radiated by the bridge raises evidently.To explore the influence of multiple tuned mass dampers (MTMDs) on structure-borne noise,the dynamic behavior of a two-track simply supported box-girder bridge with a span of 32 m was simulated as a case study.Based on a moving forces-bridge-MTMDs coupling vibration model,the optimal MTMDs parameters were derived and calculated with the flexural frequency response functions of the bridge,and then,the vibration and noise control effectivenesses of the bridge with and without MTMDs were compared respectively by applying the transient FEM and the acoustic BEM.The results showed that MTMDs are an effective device in reducing dynamic responses of a box-girder bridge ; however,as the vibration control of MTMDs aims at the first flexural mode of the bridge,the structure-borne noise reduction is not as effective as the vibration reduction,and the average reduction of sound pressure level (SPL) is about 0.5 dB for the sound filed being 25 m far from the track.

  16. Behaviors of Precast Fabricated Box Girder Bridge using Reactive Powder Concrete%预制装配式活性粉末混凝土箱梁桥的结构性能

    Institute of Scientific and Technical Information of China (English)

    魏亚雄; 方志

    2016-01-01

    A new kind of ultra-high performance cement-based material,RPC (Reactive Powder Concrete),can significantly reduce the weight of structure and decrease the inertia load,when applying to build the prefabricated beam of bridge.It has lower shrinkage and high durability after hot water cu-ring.Base on a project of a 4 ×30 m prefabricated PC continuous box girder bridge,a prefabricated box girder bridge with the same span using RPC was designed.Its mechanical properties were studied and a comparative study of the economy of the PC and RPC bridges were carried out.The results showed that, both the overall and the local mechanical properties of the RPC bridge met the specification requirements, and its stress level or deformation during service even had more safety margin.The plate section of girder became thinner,and the consumption of concrete and prestressd tendons decreased by 25.4% and 27.5%.Therefore,the prefabricated RPC box girder bridge was proven to be a favorable plan and can be applied widely in the future.%超高性能活性粉末混凝土 RPC(Reactive Powder Concrete)应用于装配式梁桥中,不仅能有效减轻结构自重、增加结构抵抗使用荷载的有效性,还能充分发挥其在热养护条件下收缩徐变小且耐久性好的优点,是一种极具应用前景的新型水泥基材料。以一座4×30 m 的普通预应力混凝土装配式连续箱梁桥为背景,提出了同等跨径的 RPC 装配式箱梁桥方案,对其结构的受力性能进行了分析,并将二者的经济性能进行了比较。结果表明:提出的 RPC 箱梁桥整体和局部受力性能均满足现行规范要求,使用阶段应力以及变形尚有较大的安全储备;采用RPC 可令主梁板件厚度减小,使混凝土和预应力筋用量分别减少25.4%和27.5%。因此,预制装配式 RPC 箱梁桥作为一种可供选择的优选方案,具有良好的推广应用前景。

  17. Suspension Bridge Flutter for Girder with Separate Control Flaps

    DEFF Research Database (Denmark)

    Huynh, T.; Thoft-Christensen, Palle

    Active vibration control of long span suspension bridge flutter using separated control flaps (SFSC) has shown to increase effectively the critical wind speed of bridges. In this paper, an SFSC calculation based on modal equations of the vertical and torsional motions of the bridge girder including...... the flaps is presented. The length of the flaps attached to the girder, the flap configuration and the flap rotational angles are parameters used to increase the critical wind speed of the bridge. To illustrate the theory a numerical example is shown for a suspension bridge of 1000m+2500m+1000m span based...

  18. 某预应力混凝土箱梁桥悬臂施工中底板纵向裂缝成因分析及处理措施%Analysis of Causes Inducing Longitudinal Cracks in Base Slabs During Cantilever Construction of A Prestressed Concrete Box Girder Bridge and Treating Measures

    Institute of Scientific and Technical Information of China (English)

    胡志红; 王攀; 邹红丹

    2015-01-01

    The bridge cited as an example in this study is a combined prestressed concrete con-tinuous beam and rigid-frame composite box girder bridge with span arrangement of(80+2 × 150+80) m.The box girder adopts the two-cell single box cross section with straight diaphragms ,cas-ted in situ in cantilevers using form travelers.During the construction of the first 8 sections ,longi-tudinal cracks were found in the base slabs of the box girder.ANSYS was used to establish the fi-nite element models of the No.1 and No.2 box girder sections and calculate the stress distribution condition of the girder under 4 load cases.By analyzing the distributive law of the cracks in the base slabs of the girder ,the transverse stress and temperature during the curing of the box girder concrete were monitored.and the causes inducing longitudinal cracks in the base slabs of the box girder was analyzed.The results of the analysis indicate that the gradient thermal loading effect in-side the concrete takes the major responsibility for longitudinal cracks.T hen the measures for in-tensifying the transverse prestressing tendons in the base slabs of box girder were proposed.The curing of base slabs should also be given enough attention.By using the aforementioned measures , no marked longitudinal cracks were found in the base slabs of the box girder during the construc-tion monitoring of the girder sections.%某预应力混凝土连续梁-刚构组合箱梁桥跨径布置为(80+2 × 150+80 ) m ,箱梁为直腹板单箱双室截面 ,采用挂篮悬臂现浇施工 ,在前8个节段的施工过程中 ,箱梁底板出现了纵向裂缝.采用ANSYS建立1号、2号节段箱梁实体有限元模型 ,计算4种荷载工况下箱体的应力分布情况 ,并监测箱梁混凝土养护过程中的横向应力和温度 ,分析了箱梁底板纵向裂缝开裂原因.分析得出混凝土内部的梯度温度荷载效应是底板产生纵向裂缝的主要原因 ,提出加强箱梁底板的横向配筋及

  19. Analysis of vibration test for the skew box girder bridge under human-induced excitation%人群荷载作用下斜箱梁桥振动试验分析

    Institute of Scientific and Technical Information of China (English)

    赵学; 王介修; 勾志硕; 贾艳敏

    2014-01-01

    By the actual test and theoretical analysis for vibration of the skew box girder bridge under human-induced excitation,the determina-tion of dynamic characteristic and the dynamic reaction under the effect of moving pedestrian,actual working state of the bridge under moving load have been studied,with safe bearing capacity and use condition of the whole structure determined.%通过对三跨预应力连续斜箱梁桥在人群荷载作用下的振动问题进行实桥测试和理论分析,测定其动态特性及在跑动的人群荷载作用下的动态响应,了解了该桥在动荷载作用下的实际工作状态,从而判断该桥整体结构的安全承载能力和使用条件。

  20. 夹芯钢板覆盖法(SPS)在钢箱梁桥正交异性桥面板维修加固中的应用与试验%Research on Application of Sandwich Plate System (SPS) on Strengthening Orthotropic Bridge Deck of Steel Box Girder Bridge

    Institute of Scientific and Technical Information of China (English)

    许传博; 胡利平

    2012-01-01

    This paper introduces the application of sandwich plate system SPS ) on strengthening of steel box girder bridge with load test being carried out to verify the effect of SPS, which can provide a reference for the similar engineering practice.%结合工程实例,介绍了夹芯钢板覆盖法(SPS)在钢箱梁桥维修加固中的应用,并通过荷载试验对其加固效果进行了检验,可为类似维修加固工程提供参考。

  1. Continuous rigid PC frame box girder cantilever pouring construction reasonable maintenance method

    Directory of Open Access Journals (Sweden)

    Wulin

    2015-08-01

    Full Text Available In recent years, prestressed concrete continuous rigid frame box girder plate and web plate produced a large number of non-structural cracks disease caused the attention of large bridge workers, to solve the problem of continuous rigid-frame structure of the cantilever of the disease, this article briefly introduced the cantilever construction method and the performance requirements of modern concrete, through to the modern concrete composition change and keeping in good health on the impact of environment on its early performance analysis summary, points out the present problems of box girder early curing, finally combining with the characteristics of modern concrete performance and the characteristics of the cantilever construction method, puts forward "model attach +manual+automatic water spray mist stick " composite curing method in order to reduce the structural cracks, provides a new train of thought.

  2. Numerical Investigation on Aerodynamic Force of Streamlined Box Girder with Uniform Air Suction

    Directory of Open Access Journals (Sweden)

    Tang Ke

    2014-06-01

    Full Text Available In the present study, the flow around a streamlined box girder with uniform air suction has been investigated numerically. Two-dimensional incompressible unsteady Reynolds averaged Navier-Stokes (URANS equations are solved in conjunction with the SST k −ω turbulence model in simulations. Taking the Great Belt Bridge girder as an example, cases of different suction positions on the girder section were discussed. The effect of the suction ratio and the angle of attack (AOA of wind also were investigated. The result showed that the aerodynamic drag force was influenced by the uniform suction through either upper surface or lower surface of the box girder. The larger the suction ratio was, the more the drag-reducing could be. The suction position and AOA had a comprehensive effect on the drag force. The vortex shedding frequency was also affected by air suction. For the aerodynamic lift force and moment, air suction showed no obvious influence. If necessary, using a combined suction scheme to reduce the aerodynamic drag force or to control the flow wake would be more efficient in engineering design.

  3. Influence of Aerodynamic Shape of Streamline Box Girder on Bridge Flutter and Vortex-induced Vibration%流线型箱梁气动外形对桥梁颤振和涡振的影响

    Institute of Scientific and Technical Information of China (English)

    王骑; 廖海黎; 李明水; 马存明

    2012-01-01

    Taken a streamline box girder for example, the influence of aerodynamic shape on bridge flutter and vertex-induced vibration ( VIV) was studied in detail. Through wind tunnel test of a 1: 50 scale section model, the influences of railing, inspection rail, rostrum, guide wing and inclined web on the flutter and VIV were discussed respectively. The results indicate that railing and inspection rail could weaken the aerodynamic performance of bridge section, while rostrum and guide wing could be used to improve the flutter and VIV performance of bridge. Special indicating is that the increase of flutter wind speed and the vanishing of VIV were all satisfied under the same condition while the slope of inclined web was 15° The brief mechanism of this phenomenon is that the lower inclined web could restrain and delay the formation and shedding of the vertex at the downwind of streamline box girder, thus could remarkably weaken the influence of vertex shedding on VIV and flutter of bridges. But the detailed aerodynamic mechanism will be studied profoundly in future. This development would be beneficial to the wind resistant design of the bridge, and has been applied successfully in the aerodynamic shape design of several long-span bridges in China.%以某流线型钢箱梁断面为例,详细研究了主梁气动外形变化对桥梁颤振和涡振性能的影响.基于1∶50节段模型风洞试验,分别研究了箱梁的栏杆、检修车轨道、风嘴、导流板,以及斜腹板对桥梁颤振及涡振性能的影响.研究表明,栏杆和检修车轨道将弱化桥梁断面的气动性能,而风嘴和导流板则对桥梁的颤振和涡振性能有利.值得提出的是,在其他气动外形保持不变,而斜腹板倾角变为15°时,桥梁的颤振性能不仅获得了较大提升,且涡振现象还可得到消除.此现象的初步机理为:较小的斜腹板倾角可阻碍和廷后流线型箱梁下风侧漩涡的形成和脱落,从而显著削弱漩涡脱

  4. 挪威Hardanger大桥钢箱梁外侧电弧喷锌工艺设计%Design of zinc arc-spraying process for outer steel box girder of Hardanger Bridge in Norway

    Institute of Scientific and Technical Information of China (English)

    仪德强; 钱胜杰; 金树军; 李敏风; 丁祥

    2012-01-01

    在承接挪威Hardanger大桥钢结构制作中,根据业主的要求,以电弧喷锌作为配套涂层底漆.为了适应钢结构涂装流水线以及佐敦公司的重防腐配套涂料,从钢结构缺陷处理等级、磨料拼配方案、喷砂技术条件、电弧喷锌设备及锌丝线材要求、电弧喷锌工艺参数以及喷锌层质量要求等方面对钢箱梁外侧电弧喷锌工艺进行了设计.%Based on the requirement of proprietor, arc zinc spray coating was used as a primer during the manufacturing of the Norwegian Hardanger bridge's steel structure. In order to adapt the steel structure coating flow line and Jotun's heavy corrosion protection accessory coating, the arc zinc spraying process of outer steel box girder was designed from aspects of pretreatment grade of defects in steel structure, composition for abrasives, sandblasting process conditions, arc zinc spraying equipment, zinc wire requirement, arc zinc spraying process parameters, quality requirement of arc sprayed zinc coating, etc.

  5. Design and test of box girder for a large wind turbine blade

    DEFF Research Database (Denmark)

    Nielsen, Per Hørlyk; Tesauro, Angelo; Bitsche, Robert

    This report is covering the structural design and full scale test of a box girder as a part of the project “Demonstration of new blade design using manufacturing process simulations” supported by the EUDP program. A box girder with a predetermined outer geometry was designed using new inventions......, which create an inner structure in the box girder. With a combination of advanced FEM analysis and the inventions it was possible to reduce the material thickness of the cap by up to 40%. The new design of the box girder was manufactured at SSP Technology A/S, where it was demonstrated...... that the manufacturing process could include the new inventions. Subsequently the box girder was transported to the blade test facility at DTU Wind Energy. A series of test was performed with the blade to investigate the behaviour during loading, and finally the girder was loaded to ultimate failure. The report includes...

  6. Preliminary study to facilitate smart structure systems in bridge girders

    Science.gov (United States)

    Kirkpatrick, Thomas C.; Peterson, Danford O.; Rossi, Peter J.; Ray, Laura R.; Livingston, Richard A.

    1999-05-01

    Sensors are currently available and used to monitor structural performance and loads incurred by bridges already in service. However, there has been limited research concerning the stresses that steel bridge girders endure during transport from the manufacturer to the job site and during the installation process. This paper reports the measured stresses on steel bridge girders during transportation from Lancaster, PA to Hanover, NH and during construction of the Ledyard Bridge on the New Hampshire - Vermont border. Two different monitoring system were developed for this data acquisition in a mobile environment. The first, a fiber optic strain monitoring system, utilizing Bragg grating technology. The second utilized an electrical- resistive foil strain gage network, in conjunction with wireless telemetry equipment. Together, these two systems formed a smart structure system for monitoring bridge girders while confirming the accuracy of data gathered through redundancy. Result conclusively demonstrated for the first time, that stresses in beams during transportation are significant and approach the factor of safety margin in girder design.

  7. Analysis of Fatigue Stress Property of Steel Box Girder of Jiangyin Changjiang River Bridge%江阴长江大桥钢箱梁疲劳应力特征分析

    Institute of Scientific and Technical Information of China (English)

    吉伯海; 叶枝; 傅中秋; 汪锋; 孙洪滨

    2016-01-01

    为准确评估钢桥结构的疲劳损伤状态和剩余疲劳寿命,以江阴长江大桥为背景,对该桥钢箱梁疲劳裂纹产生位置进行连续疲劳应变监测,获取应变时程数据,结合雨流计数法技术建立日疲劳应力谱;分析应力幅~循环次数分布规律;研究累积损伤度分布特征,建立损伤度分布模型,计算不同车道构造细节疲劳损伤度和剩余寿命。研究结果表明:钢箱梁顶板测点、U肋与横隔板焊接末端处、弧形缺口有效截面最小处均以压应力为主,U 肋以拉应力为主;应力幅累积循环次数分布服从Weibull函数分布;疲劳累积损伤度分布服从Boltzman函数分布,顶板与U肋连接处U肋腹板沿横桥向慢车道疲劳损伤较快车道损伤大,下游车道较上游车道损伤大,其中下游慢车道U肋腹板细节疲劳损伤最大。%To accurately evaluate the fatigue damaging condition and remaining fatigue life of steel bridge structure ,the Jiangyin Changjiang River Bridge was cited as an example .Continuous fatigue strain monitoring was conducted at the locations where fatigue cracks were found on the steel box girder to gain real‐time strain data .The monitoring data ,combined with the rain flow counting method ,were used to set up the daily fatigue stress spectrum to analyze the distribution law of S~ N curve .The distribution law of fatigue accumulating damage was studied .The model of damage distribution was set up ,to calculate the fatigue damages and remaining life of different structural details of the traffic lane .T he results of the study demonstrate that compressive stress was dominant at the testing locations in the steel box girder ,ends of U‐rib and diaphragm welds and least effective cross section of the arc notches ,whereas tensile stress was found primarily on U ribs .The distribution of the accumulated stress cycle follows the way of Weibull function distribu‐tion .The distribution

  8. Life-Cycle Management Strategy on Steel Girders in Bridges

    Directory of Open Access Journals (Sweden)

    Kevin K. L. So

    2012-01-01

    Full Text Available The major problems affecting the service life of bridges are related to various factors such as fatigue-sensitive details, increased service loads, corrosion deterioration, and the lack of proper maintenance. Among them, corrosion deterioration and fatigue damages of structures particularly to steel girder bridges are the most common ones. Bridges of different structural forms, at different locations or under different climates, may suffer from various degrees of deterioration. Steel girders at different positions of a bridge may also suffer from different degrees of damage. How to effectively maintain the bridge asset at a minimal cost and how to predict the time for future works are crucial, particularly when government funding sources become stretched. A comprehensive bridge management framework assisting stakeholders to appropriately and reasonably prioritize their future maintenance-related works in their bridge stocks, such that stakeholders can better allocate the limited resources, is utmost concerned. This paper proposes an integrated life-cycle management (LCM strategy on steel girders in bridges in which corrosion deterioration and fatigue damage prediction models are mapped with girders’ performance conditions. A practical example to demonstrate the applicability of the proposed LCM strategy is also illustrated.

  9. Probabilistic Model of Fatigue Damage in Steel Box-girder Bridge Subject to Stochastic Vehicle Loads%随机车载下钢箱梁桥疲劳损伤概率模型

    Institute of Scientific and Technical Information of China (English)

    罗媛; 颜东煌; 鲁乃唯; 汪勤用

    2016-01-01

    将具有确定性参数的典型疲劳车辆模型改进为随机疲劳车流模型,采用小样本车辆轴重与等效疲劳应力数据拟合响应面的方法解决了车流作用下桥梁有限元应力时程分析耗时过长的问题.提出钢箱梁顶板-U肋疲劳损伤概率建模方法,最后将疲劳损伤概率模型应用于可靠度评估领域,揭示了车流参数对结构疲劳可靠指标的影响规律.研究结果表明:行车道重载车辆的较高占有率是导致其顶板-U肋疲劳可靠指标远低于超车道的重要原因;车辆轴重的增长致使钢箱梁疲劳可靠指标迅速降低,车重年线性增长系数由0增长至1%时,行车道顶板-U肋处100 a的疲劳可靠指标由3.42下降至0.72.随机疲劳车流模型与疲劳损伤概率模型具有一定的应用前景.%The typical fatigue truck model with deterministic parameters is developed to be a stochastic vehicle flow model. The time-consuming problem of bridge finite element analysis under traffic flow loads is solved by using a response surface method to approximate the function between vehicle axle weight of a few training data and equivalent fatigue stresses. A probabilistic fatigue damage modeling method applies to rib-to-deck details of steel box-girder bridges is presented. Finally, the fatigue damage model is applied to the reliability assessment, and the influence of traffic flow parameters on structural fatigue reliability is revealed. The numerical result indicates that (1) the higher occupancy rate of heavy vehicle flow in the slow lane is the main reason for the decrease of the fatigue reliability of corresponding rib-to-deck details compared with the fast lane;(2) the increase of the vehicle axle weight causes a rapid decrease of the fatigue reliability index of the steel box girders, when the annual linear growth factor increases from 0 to 1%, the fatigue reliability index of rib-to-deck detail in the slow lane decreases from 3. 42 to 0. 72 . There is

  10. 双层桥箱内壁车辆碰撞混凝土损伤仿真研究%Simulation Study on Concrete Damage of the Inner Box Collision of the Double Decked Continuous Box Girder Bridge

    Institute of Scientific and Technical Information of China (English)

    沈正峰; 方金苗; 郑净

    2014-01-01

    Double-decked continuous box bridge is a new structure system and how to evaluate the structure damage caused by vehicle collision inner box has a great significance to the wide application of the new structure .This paper researches all conditions of structure damages caused by vehicle collision inner box by means of computerized simulation .The study finds out the concrete injured parts and its degree ,analysis the sensitive factor of concrete damage ,which provides suggestions for the design of double-decked bridge .%双层连续箱梁桥是一种新型结构体系,如何评价车辆撞击箱梁内部造成的结构损伤对于这种新型结构的广泛运用具有重要意义。通过计算机仿真技术研究各种工况下车辆对箱梁桥内壁撞击引起的结构损伤情况,得出混凝土损伤部位以及程度,分析影响混凝土损伤的敏感因子,为双层桥结构设计提供参考。

  11. Design and test of box girder for a large wind turbine blade

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Per H.; Tesauro, A.; Bitsche, R. [Technical Univ. of Denmark. DTU Wind Energy, DTU Risoe Campus, Roskilde (Denmark)] [and others

    2012-09-15

    This report is covering the structural design and full scale test of a box girder as a part of the project ''Demonstration of new blade design using manufacturing process simulations'' supported by the EUDP program. A box girder with a predetermined outer geometry was designed using new inventions, which create an inner structure in the box girder. With a combination of advanced FEM analysis and the inventions it was possible to reduce the material thickness of the cap by up to 40%. The new design of the box girder was manufactured at SSP Technology A/S, where it was demonstrated that the manufacturing process could include the new inventions. Subsequently the box girder was transported to the blade test facility at DTU Wind Energy. A series of test was performed with the blade to investigate the behaviour during loading, and finally the girder was loaded to ultimate failure. The report includes the description of the test setup, the test and an overview over the results from the test performed on the box girder. During the final test the box girder failed at 58 % of the expected ultimate load. Unfortunately, no definite conclusion could be made concerning the failure mechanism. (Author)

  12. Buffeting Response of Suspension Bridge Girder with Separate Control Flaps

    DEFF Research Database (Denmark)

    Huynh, Truc; Thoft-Christensen, Palle

    This paper presents the calculation of the root mean square (RMS) response of a suspension bridge using separate control flaps (SCF) in turbulence conditions. It is assumed that the mean wind velocity is not large enough to cause coupled vibrations and that single mode buffeting response is of in......This paper presents the calculation of the root mean square (RMS) response of a suspension bridge using separate control flaps (SCF) in turbulence conditions. It is assumed that the mean wind velocity is not large enough to cause coupled vibrations and that single mode buffeting response...... on the basis of independent flutter derivatives and independent aeroelastic coefficients from the girder and from the flaps. The theory is demonstrated by a numerical example based on a long-span suspension bridge model with the Great Belt girder....

  13. 箱桁梁断面斜拉桥涡振性能及抑振措施的研究%Research on vortex-induced vibration and its control for cable-stayed bridge with box-truss composite girder

    Institute of Scientific and Technical Information of China (English)

    冯丛; 华旭刚; 胡腾飞; 陈强; 陈政清

    2016-01-01

    T he cable-stayed Dongting Lake railway bridge under construction was case-studied in this paper. A finite element modeling of the cable-stayed bridge with box-truss composite girder and its vortex-induced vibration were analyzed. T hree finite element schemes for modeling box-truss girder of the bridge,namely the spatial beam model ( SBM) ,spatial plate-beam model( SPBM ) and spatial shell model( SSM ) ,were compared in terms of modal frequency,equivalent mass and mass moment of inertia per unit length. It shows that the results from the SPBM and the SSM are basically the same,while the SBM can't accurately produce the equivalent mass unit length girder for some higher-order lateral modes. T he vortex-induce vibration of the box-truss composite girder was tested in wind tunnel by flexibly mounted rigid sectional model tests. T he results indicate that this cross-section type may experience large-amplitude vertical vortex-induced vibrations at wind attack angle of -3°,which is caused by the vortex shedding at the leading edge of the box-girder part of the cross-section. T he effects of aerodynamic appendix for suppression of vortex-induced vibrations w ere studied and it is found that tw o stabilizers beneath the open orthotropic deck dramatically reduce the vibration amplitude. T he vibration amplitude is within the limit given in design specification when the height of stabilizers is half of the box-girder height; and the vortex-induced vibrations completely diminish when the height of stabilizers is the same as the box-girder height.%以在建的洞庭湖铁路三塔斜拉桥为工程背景,分析了箱桁断面斜拉桥主梁的建模方法以及涡激共振性能。首先比较了主梁建模的空间杆系模型、梁壳组合模型以及三维壳体模型在模态频率、主梁单位长度等效质量和等效质量惯性矩的差异。结果表明,三种模型的模态分析结果基本相近,但空间杆系模型不能准确得到高阶侧弯模

  14. Structural Health Monitoring of Precast Concrete Box Girders Using Selected Vibration-Based Damage Detection Methods

    Directory of Open Access Journals (Sweden)

    Zhengjie Zhou

    2010-01-01

    Full Text Available Precast, prestressed concrete box girders are commonly used as superstructure components for short and medium span bridges. Their configuration and typical side-by-side placement make large portions of these elements inaccessible for visual inspection or the application of nondestructive testing techniques. This paper demonstrates that vibration-based damage detection (VBDD is an effective alternative for monitoring their structural health. A box girder removed from a dismantled bridge was used to evaluate the ability of five different VBDD algorithms to detect and localize low levels of spalling damage, with a focus on using a small number of sensors and only the fundamental mode of vibration. All methods were capable of detecting and localizing damage to a region within approximately 1.6 times the longitudinal spacing between as few as six uniformly distributed accelerometers. Strain gauges configured to measure curvature were also effective, but tended to be susceptible to large errors in near support damage cases. Finite element analyses demonstrated that increasing the number of sensor locations leads to a proportional increase in localization accuracy, while the use of additional modes provides little advantage and can sometimes lead to a deterioration in the performance of the VBDD techniques.

  15. Closure technique for the hybrid girder cable stayed bridge of Edong Bridge

    Institute of Scientific and Technical Information of China (English)

    Liu Minghu; Tan Hao; Xu GuoPing; Zhao Canhui

    2012-01-01

    Based on Edong Yangtze River Bridge, which is the second longest hybrid girder cable stayed bridge with 926 m long main span, the influencing factors and crucial techniques of the main span closure method for long span hybrid girder cable stayed bridge are studied. After theoretical analysis, numerical evaluation and practical test, the loading assistant closure method is employed in Edong Yangtze River Bridge. The loading assistant closure method, with better thermal adaptability and less influence on bridge line and the forced status, can meet the requirements of the unstressed state control method. Based on the mentioned advantages, the loading assistant closure method is applicable to long span hybrid girder cable stayed bridges. The conclusion can provide a reference for the further design of the similar brid~es.

  16. Pulling Force Analysis of Shear Studs in Steel-concrete Composite Continuous Box Girder of Hongkong-Zhuhai-Macau Bridge%港珠澳大桥组合连续箱梁桥剪力钉受力分析

    Institute of Scientific and Technical Information of China (English)

    刘沐宇; 王松; 张强

    2013-01-01

    show that the shear stdus between concrete deck and steel box girder of section with longitudinal beam has better connectivity than section without longitudinal beam.

  17. Analysis of ultimate bearing capacity of prestressed concrete box -girder bridge with large -cantilever -wing%大悬臂展翅预应力混凝土宽箱梁桥极限承载力分析

    Institute of Scientific and Technical Information of China (English)

    余晓琳; 贾布裕; 杨铮; 颜全胜

    2015-01-01

    To study the ultimate bearing capacity of the large cantilever structure,an accurate space finite ele-ment model was built for numerical analysis with the background of a prestressed concrete box -girder bridge with large -cantilevev -wing.Taking into account of the geometric nonlinearity and the material nonlinearity, the structure ultimate bearing capacity and the distribution regularity of cracks under three load cases(eccentric concentrated load,symmetrical concentrated load and uniform distributed load)were analyzed.It is concluded that the structure ultimate bearing capacity under the load case of symmetrical load is larger than that under the case of asymmetrical load;the distributions of the stress and cracks under the load case of asymmetrical load are also asymmetrical and cracks are more likely to appear in the root of the cantilever wing.The stress condition of side span is worse than mid -span under uniformly distributed load.%针对大悬臂展翅结构的极限承载能力问题,以某大悬臂展翅预应力混凝土宽箱梁桥为实际工程背景,建立精细的空间有限元模型进行数值分析。考虑结构几何非线性和材料非线性,研究偏心集中荷载、对称集中荷载、均布荷载3种工况作用下,结构的极限承载能力及裂缝的分布规律。结果表明,对称加载形式的极限承载能力大于非对称加载形式的极限承载能力;非对称荷载作用下,桥梁应力及裂缝分布也具有较大非对称性,且悬臂板根部更加容易出现裂缝,均布荷载作用下,桥梁边跨应力状况劣于中跨。

  18. Research on the stiffening girder erection sequence of three-tower suspension bridge

    Institute of Scientific and Technical Information of China (English)

    Zheng Runqing; Luo Xiheng

    2012-01-01

    Compared to the conventional two-tower suspension bridge, the three-tower suspension bridge has obviously different characteristics in structural performance because of the extra middle tower and main span. The construction sequence for the stiffening girder is significantly different between the three-tower suspension bridge and the two-tower suspension bridge. The tangential angle of the main cable is one of the controlling factors of the stiffening girder erection stage for a suspension bridge. According to 5 feasible cases for the stiffening girder erection scheme in Taizhou Bridge, the research about the tangential angle in each case mentioned above was made, and some factors that should be taken into account for the erection scheme of stiffening girder were pointed out.

  19. Study of Dynamic Performance Finite Element Modeling Methods for Box-Truss Composite Girder Railway Cable-Stayed Bridge%箱桁组合梁铁路斜拉桥动力特性有限元建模方法研究

    Institute of Scientific and Technical Information of China (English)

    张无畏; 胡腾飞; 陈长胜; 荣浩

    2016-01-01

    study show that modal analysis re‐sults gained from the three model calculations are basically consistent , the frequency and main girder equivalent mass gained from the combined plate‐beam element model and spatial shell ele‐ment model are approximate ,nevertheless ,the spatial beam element model could not accurately calculate the main girder uniform equivalent mass of the high‐order lateral bending modes .As an exception ,the dynamic performance of the steel box girder cable‐stayed bridge without truss and with open cross section was analyzed independently .The results of the analysis show that the com‐bined plate‐beam element model and spatial shell element model are in good agreement ,but the in‐ertia moment of the main girder uniform equivalent mass under the first order torsional mode gained from the spatial beam element model reveal an error of 9% .T russ has slight influence on the lateral bending frequency of the main girder ,but can improve the vertical bending frequency and torsional frequency of the main girder ,w hich is favorable for the wind resistant performance of the bridge .

  20. Lateral static and dynamic characteristics of thin-walled box girder

    Institute of Scientific and Technical Information of China (English)

    CAN Yan-an; ZHOU Guang-chun

    2009-01-01

    To analyze the static and dynamic behaviors of the thin-walled box girder in its lateral webs in consideration of shear lag effect and shear deformation, an approach based on the minimum potential principle is introduced in this paper. Both static and dynamic response equations as well as the corresponding natural boundary conditions of the box girder are deduced. Meanwhile, three generalized displacement functions:w(x), U(x) and 0(x) are employed and their differences in the calculus of variation are quantitatively investigated. The comparison of finite shell element results with analytical results of calculation examples validates the feasibility of the proposed approach.

  1. Sensitive Analysis on Seismic Response of Simply Supported Box Girder Bridge on High Speed Railway Using Friction Pendulum Bearings and U-shaped Steel Combined Earthquake Protection Device%采用摩擦摆支座及U型钢防落梁装置的高速铁路简支箱梁桥地震响应敏感性分析

    Institute of Scientific and Technical Information of China (English)

    臧晓秋; 曹志峰; 吴成亮

    2016-01-01

    以高速铁路简支箱梁桥隔震研究为例,建立了采用摩擦摆支座与 U 型钢防落梁装置组合地震保护方案的全桥地震响应分析模型,针对支座位移、墩底剪力、墩底弯矩等地震响应,考虑了场地类别、桥墩高度、桥梁跨数、桥梁跨度、激励方向等影响因素,并根据各因素选定的水平级别,实施了混合正交试验,再应用极差分析方法对支座位移、墩底剪力、墩底弯矩等地震响应进行了影响因素的敏感性分析,明确了各因素对相关响应量影响的主次情况,为高速铁路简支箱梁桥隔震研究及优化设计奠定了基础。%In this paper,the seismic isolation of simply supported box girder bridges on high speed railway was studied. A bridge model with friction pendulum bearings and a U-shaped steel combined earthquake protection device was built for seismic response analysis,including the seismic response of bearing displacement,and shear and moment at the pier bottom. Multiple factors including site types,pier height,number of bridge spans,bridge span length and excitation direction were considered. A mixed orthogonal test was carried out according to the selected level of each factor. Using range analysis method,sensitivity analysis of each factor was carried out on the seismic response of bearing displacement,and shear and moment at the pier bottom. The primary and secondary cases of the impact of various factors on the relevant response were analyzed. It may provide guidelines for seismic isolation and design optimization of simply supported box girder bridges on high speed railway.

  2. Design of bridge crane girder strain acquisition system based on virtual instrument

    Directory of Open Access Journals (Sweden)

    Wenxue LIU

    Full Text Available Girder is an important part of the bridge crane, which is also the main force element. In order to prevent accidents, it is necessary to collect the bridge crane girder stress data to analyse the fatigue life. This paper constructs a bridge crane girder strain acquisition system. The hardware system consists of sensors, connectors, data acquisition cards, wireless data transmission groups, POE power and host computer. The software system consists of NI MAX to interface with the computer's NI hardware and software resources,and LabVIEW programming to display and storage the girder strain data. Through this system, positions and working days strain data acquisition for the 50/10 t bridge crane girder gets the key positions strain data. The results show that the girder strain data acquisition system runs stably, channel signals of acquisition task transmit accurately, and the terminal data stores competely, meeting the detection requirements, which provides an important data support for the subsequent fatigue analysis and accurate remaining service life prediction of the crane girder.

  3. 基于 WIM 数据的上海某大桥钢箱梁应力谱研究%Fatigue Stress Spectrum Study of the Steel Box Girder of Shanghai Certain Bridge,Based on the Analysis of WIM Data

    Institute of Scientific and Technical Information of China (English)

    徐昊; 胡明敏

    2014-01-01

    斜拉桥以其自身的优点成为当今大跨度桥梁中的主流桥型,然而,投入使用一段时间后,由于运营车辆总重和交通量交替变化,钢桥所面临的疲劳问题正日趋严重。本文以上海某大桥为工程背景,利用动态称重系统采集到的车辆载荷相关数据,依据等效疲劳损伤原理,推导出代表实际运营车辆载荷谱,采用泄水法,建立南塔钢箱梁的细节应力谱,为上海某大桥疲劳损伤及寿命评估提供可靠依据。%Cable-stayed Bridge becomes the main stream bridge in the large span bridge construction because of its advantages and was built all over the world .However ,after a period of time ,the fatigue problem of the steel bridge faced with is becoming more and more serious .The representative of actual operation vehicle load spectrum is deduced with the vehicle load data collected by the dynamic weighing system and the equivalent fatigue damage theory based on the Shanghai Certain Bridge . The paper also adopted the discharge water method to build the stress spectrum of the steel box girder of The South Tower and to provide the reliable ba-sis for fatigue damage and life assessment of Shanghai Yangtze River Bridge .

  4. Performance evaluation of corrosion-affected reinforced concrete bridge girders using Markov chains with fuzzy states

    Indian Academy of Sciences (India)

    M B ANOOP; K BALAJI RAO

    2016-08-01

    A methodology for performance evaluation of reinforced concrete bridge girders in corrosive environments is proposed. The methodology uses the concept of performability and considers both serviceability- and ultimate-limit states. The serviceability limit states are defined based on the degree of cracking (characterized by crack width) in the girder due to chloride induced corrosion of reinforcement, and the ultimate limit states are defined based on the flexural load carrying capacity of the girder (characterized in terms of rating factor using the load and resistance factor rating method). The condition of the bridge girder is specified by the assignment of a condition state from a set of predefined condition states. Generally, the classification of condition states is linguistic, while the condition states are considered to be mutually exclusive and collectivelyexhaustive. In the present study, the condition states of the bridge girder are also represented by fuzzy sets to consider the ambiguities arising due to the linguistic classification of condition states. A non-homogeneous Markov chain (MC) model is used for modeling the condition state evolution of the bridge girder with time. The usefulness of the proposed methodology is demonstrated through a case study of a severely distressed beam of the Rocky Point Viaduct. The results obtained using the proposed approach are compared with those obtained using conventional MC model. It is noted that the use of MC with fuzzy states leads to conservative decision making for the problem considered in the case study.

  5. Full Scale Test of a SSP 34m box girder 1. Data report

    DEFF Research Database (Denmark)

    Jensen, Find Mølholt; Branner, Kim; Nielsen, Per Hørlyk;

    This report presents the setup and result of a full-scale test of a reinforced glass fibre/epoxy box girder used in 34m wind turbine blade. The tests were performed at the Blaest test facility in August 2006. The test is an important part of a research project established in cooperation between...... the box girder was loaded until failure. A comprehensive description of the test setup is given. This report deals only with tests and results. There are no conclusions on the data in this report, but references are given to publications, where the data are used and compared with FEM etc. Various kinds...... of measuring equipment have been used during these tests: acoustic emission, 330 strain gauges, 24 mechanical displacement devices and two optical deformation measuring systems. The mechanical displacement devices measured both global (absolute) and local (relative) deflection and the optical systems measured...

  6. Study of Parameters Influencing Load Bearing Performance of No .0 Block in PC Continuous Box Girder Bridge%PC连续箱梁桥0号块受力性能的影响参数分析

    Institute of Scientific and Technical Information of China (English)

    熊敏; 胡峰强; 邱衍坚; 徐义标; 冯小毛; 刘蕙婷

    2016-01-01

    To study the load bearing performance of No .0 blocks in the superstructure of PC continuous box beam bridge ,a PC continuous box beam bridge with span arrangement of (55+90+90+55) m was taken as the study background .The spatial finite element model of the No .0 block was established to study the variation of parameters on the load bearing capacity of No .0 block ,including the height of the piers ,prestressing loss along the prestressing tendons and the constraints of the bearings .And the features of the spatial stress of the No .0 block during the lon‐gest cantilever construction stage and in the completed bridge state were analyzed .The results of the analysis indicate that the stress in the intersection of the bottom slab of the No .0 block box beam and the bearings is prone to the influence of pier height ,therefore ,the influence of piers should be taken into account during the model establishment ,and pier heights can choose one time of the beam depth to simplify the process .The surrounding prestressing distribution exerts signifi‐cant influence on the load bearing capacity of No .0 block .During the operation period ,if the stress local distortion of the No .0 block at the bearings is not considered ,the fixed constraints can be used to replace the real bearings in the stress calculation of No .0 block as a simplified treat‐ment .At the locations where constant cross section of the diaphragm showing abrupt change ,the main tensile stress in the No .0 block will exceed the values prescribed in the code .%为研究PC连续箱梁桥0号块建模参数对其受力性能的影响程度,以选取合理的建模参数,以某跨度为(55+90+90+55) m的PC连续箱梁桥为工程背景,建立0号块空间有限元模型,分析不同桥墩高度、预应力筋沿程预应力损失、支座约束等参数下0号块受力性能的变化规律,以及最大悬臂施工阶段和成桥阶段0号块的空间应力特点。分析结果表明:0

  7. Numerical Analysis on Variation of Dynamic Response of Girder Bridges with Torsional Reinforcement Panels

    Directory of Open Access Journals (Sweden)

    Kang Jae-Yoon

    2015-01-01

    Full Text Available The dynamic flexural behaviour of the railway bridge is influenced by its torsional behaviour. Especially, in the case of girder railway bridges, the dynamic response tends to amplify when the natural frequency in flexure (1st vibration mode is close to that in torsion (2nd vibration mode. In order to prevent such situation, it is necessary to adopt a flexural-to-torsional natural frequency ratio larger than 120%. This study proposes a solution shifting the natural frequency in torsion to high frequency range and restraining torsion by installing concrete panels on the bottom flange of the girder so as to prevent the superposition of the responses in the girder bridge. The applicability of this solution is examined by finite element analysis of the shift of the torsional natural frequency and change in the dynamic response according to the installation of the concrete panels. The analytical results for a 30 m-span girder railway bridge indicate that installing the concrete panels increases the natural frequency in torsion by restraining the torsional behaviour and reduces also the overall dynamic response. It is seen that the installation of 100 mm-thick concrete panels along a section of 4 m at both extremities of the girder can reduce the dynamic response by more than 30%.

  8. Utmost Protective Life of Arc Spray Al Coating and Large Area Long Term Anti-corrosion for Steel Box Girder Bridge%电弧喷铝涂层的保护极限及钢箱梁桥大面积长效防腐

    Institute of Scientific and Technical Information of China (English)

    陈建阳; 肖跃文; 李雄晖; 沈承金

    2001-01-01

    结合武汉军山长江公路大桥钢箱梁防腐,分析大气腐蚀环境和影响因素,研究电弧喷铝涂层腐蚀失效机理和耐腐蚀性,确定电弧喷铝涂层有效保护的极限涂层厚度和极限涂层破损率,并针对钢箱粱桥特点,设计制作机械化电弧喷涂设备,进行大面积长效防腐施工。%In terms of the protective for steel box girder of Wuhan Junshan Changjiang Bridge, atmospheric corrosion environment and influencing factors are analyzed, invalidation mechanism of are spray Al coating due to corrosion and ability for anti-corrosion are studied, utrnost thickness of arc spray Al coating for effective protection and utmost breakage rate of coating are determined. Automatic arc spray equipments are designed and made for large area long term anti-corrosion.

  9. 港珠澳大桥浅水区非通航孔桥组合梁设计%Design of Composite Girders for Non-Navigable Span Bridge of Hong Kong-Zhuhai-Macau Bridge in Shallow Water Area

    Institute of Scientific and Technical Information of China (English)

    罗扣; 王东晖; 张强

    2013-01-01

    The main part of the Hong Kong-Zhuhai-Macau Bridge is a part of the combined bridge and tunnel,of which the non-navigable span bridge in the shallow water area is the 85 m span continuous composite girder bridge that totally has 64 spans of the composite girders and is 5 440 m in length.The span arrangement of the bridge mainly includes two kinds of arrangement of 6)× 85 m and 5)× 85 m.The composite girders are the separated continuous single-cell singlebox girders with constant depth and specifically are composed of the open steel box girders and the concrete deck slabs that are connected each other via shear studs.A steel box girder is the inverted trapezoid structure,a concrete deck slab is the precast full slab in the transverse direction and the grooves are pre-reserved at the locations of the shear studs.To improve the transverse mechanical behavior of the deck slabs,the stringers are set in the sections of the composite girders and to keep the integrity of the slabs,the shear studs are arranged in a way of clustering.The composite girders are erected and installed in each full span by the large transportation and erection floating crane and the girders are closed span by span.%港珠澳大桥主体工程采用桥隧组合方案,其中浅水区非通航孔桥采用85 m连续组合梁桥形式,全长5 440m,共64孔,跨径布置主要采用6×85 m和5×85m2种形式.组合梁采用单箱单室分幅等高连续梁,由开口钢箱梁和混凝土桥面板通过剪力钉联结而成.钢箱梁为倒梯形结构;混凝土桥面板为横向整块预制,在剪力钉处设置预留槽.为改善混凝土桥面板的横向受力性能,该桥组合梁截面设置小纵梁;为保持桥面板的整体性,剪力钉采用集束式布置方式.组合梁采用大型运架一体浮吊整孔安装架设,逐孔合龙.

  10. Numerical Simulation for Progressive Collapse of Continuous Girder Bridge Subjected to Ship Impact

    Institute of Scientific and Technical Information of China (English)

    田力; 黄飞

    2014-01-01

    The three-stage simulation method based on LS-DYNA was introduced in this study to simulate the pro-gressive collapse of a continuous girder bridge after a ship-bridge collision. The pile-soil dynamic interaction and the initial stress and deformation of the whole bridge before the collision were considered. By analyzing the damage, de-formation, stress distribution and collapse process of the whole bridge, the results show that the displacement response of the cap beam lags behind the pile cap. The response order of the whole bridge’s components depends on their dis-tances from the collision region. The plastic deformation of soil around piles has a positive effect on delaying the fur-ther increase in the displacement of piles. The impacted pier’s losing stability and its superstructure’s excessive defor-mation are the main reasons leading to the progressive collapse of the continuous girder bridge.

  11. 铁路混合梁钢混结合段钢箱梁关键施工技术%Key Construction Technology for Steel-box Girder of Steel-Concrete Joint Section of Railway Hybrid Girder

    Institute of Scientific and Technical Information of China (English)

    任世朋; 朱元元; 闫明赛; 孙小猛; 徐登云

    2015-01-01

    The main bridge of Yongjiang river is the first railway hybrid girder cable-stayed bridge in China. Taking account of construction, geology and environment, the paper analyzes the inapplicability of traditional construction methods and proposes the method of matching and slipping the modules of steel-box girder of the steel-concrete section, addresses the principle of slicing the steel-concrete joint section, the design of pile-pillar-girder support, the structure of self-balanced girder moving slide, the integrated formwork for sliding and concreting and the technology of matching and slipping the module of the steel-concrete section. The paper also summarizes the key points of construction control during matching and sliding processes.%甬江主桥为国内第一座铁路混合梁斜拉桥,在钢混结合段钢箱梁施工中,综合分析构造、地质、环境等因素,阐述传统施工方法的不适应性,提出钢混结合段钢箱梁模块组拼滑移方法。详细介绍结合段钢箱梁模块划分原则、桩柱梁式支架设计、自平衡移梁滑道构造、滑移浇筑一体式胎架及模块匹配滑移技术,总结钢混结合段钢箱梁模块组拼滑移施工控制要点。

  12. 钢箱梁典型病害分析及其检测与维护技术研究%Research on Typical Defects Analysis of Steel Box Girder and Its Testing and Maintenance Technology

    Institute of Scientific and Technical Information of China (English)

    姜竹生; 瞿涛; 吕磊; 吉伯海

    2011-01-01

    基于对我国钢箱梁桥的钢箱梁病害调查,总结出我国钢箱粱典型病害的类型,分析各种钢箱梁典型病害产生的机理及导致其破坏的原因,提出了钢箱梁病害的日常检测与维护技术.针对钢箱梁的涂装劣化、钢材腐蚀、结构性损伤等病害,给出了日常检测与维护的主要项目,介绍了人工目视检测、超声波检测、磁粉检测及涡流检测等主要的检测方法的工作原理、优缺点和适用范围.%Based on the survey of China steel box girder bridges' steel box girder defects, summing up the typical defects of China steel box girder, we analyse every typical defect production mechanism and the reasons of leading to destruction of steel box girder, and propose steel box girder defects' daily testing and maintenance technology. According to coating for the deterioration, steel corrosion, structural damage and other defects of steel box girder, we give the main items of the daily testing and maintenance technology and the main detection methods including manual visual inspection, ultrasonic testing, magnetic particle testing and eddy current testing. Studying the working principle of above testing methods, advantages and disadvantages, and scope of application, should be selected based on the actual requirements in the project.

  13. Damage investigation of girder bridges under the Wenchuan earthquake and corresponding seismic design recommendations

    Institute of Scientific and Technical Information of China (English)

    Li Jianzhong; Peng Tianbo; Xu yan

    2008-01-01

    An investigation of girder bridges on National Highway 213 and the Doujiangyan-Wenchuan expressway after the Wenchuan earthquake showed that typical types of damage included:span collapses due to unseating at expansion joints;shear key failure;and damage of the expansion joint due to the slide-induced large relative displacement between the bottom of the girder and the top of the laminated-rubber bearing.This slide,however,can actually act as a form of isolation for the substructure,and as a result,the piers and foundation of most of the bridges on state route 213 suffered minor damage.The exception was the Baihua Bridge,which suffered severe damage.Corresponding seismic design recommendations are presented based on this investigation.

  14. Prediction of Fatigue Life of a Continuous Bridge Girder Based on Vehicle Induced Stress History

    Directory of Open Access Journals (Sweden)

    V.G. Rao

    2003-01-01

    Full Text Available The fatigue damage assessment of bridge components by conducting a full scale fatigue testing is often prohibitive. A need, therefore, exists to estimate the fatigue damage in bridge components by a simulation of bridge-vehicle interaction dynamics due to the action of the actual traffic. In the present paper, a systematic method has been outlined to find the fatigue damage in the continuous bridge girder based on stress range frequency histogram and fatigue strength parameters of the bridge materials. Vehicle induced time history of maximum flexural stresses has been obtained by Monte Carlo simulation process and utilized to develop the stress range frequency histogram taking into consideration of the annual traffic volume. The linear damage accumulation theory is then applied to calculate cumulative damage index and fatigue life of the bridge. Effect of the bridge span, pavement condition, increase of vehicle operating speed, weight and suspension characteristics on fatigue life of the bridge have been examined.

  15. Key Technology of the Fabrication and Erection of Steel-concrete Composite Girder on Integral Span of Hong Kong-Zhuhai-Macao Bridge%港珠澳大桥钢-混组合梁制造及安装关键技术

    Institute of Scientific and Technical Information of China (English)

    王艳峰; 潘军

    2015-01-01

    港珠澳大桥浅水区非通航孔桥上部结构采用钢-混组合连续梁。文中主要从桥面板预制、钢主梁整孔制造、钢主梁桥面板组合、组合梁整孔运架,以及组合梁体系转换技术方面阐述了组合梁整孔制造整孔架设技术,体现了大型构件海上施工的“大型化、标准化、工厂化、装配化”理念。%The non-navigable bridge in the shallow water area of the Hong Kong-Zhuhai-Macao Bridge is made of steel-concrete composite structure in the form of continuous box girder structure.This arti-cle expounded the technology of integral fabrication and erection on box girder from fabrication of the precast concrete bridge deck,fabrication of integral span on box girder,combined with steel box gird-er and bridge deck,transport and erection on composite girder,stress system transformation on com-posite girder.It shows the advanced construction concept which is″large-scale,industrialized,stand-ardized and assembled″ in the marine construction.

  16. Numerical analysis of dynamic response of vehicle–bridge coupled system on long-span continuous girder bridge

    Directory of Open Access Journals (Sweden)

    Lipeng An

    2016-07-01

    Full Text Available To systematically study the vehicle–bridge coupled dynamic response and its change rule with different parameters, a vehicle model with seven degrees of freedom was built and the total potential energy of vehicle space vibration system was deduced. Considering the stimulation of road roughness, the dynamic response equation of vehicle–bridge coupled system was established in accordance with the elastic system principle of total potential energy with stationary value and the “set-in-right-position” rule. On the basis of the self-compiled Fortran program and bridge engineering, the dynamic response of long-span continuous girder bridge under vehicle load was studied. This study also included the calculation of vehicle impact coefficient, evaluation of vibration comfort, and analysis of dynamic response parameters. Results show the impact coefficient changes with lane number and is larger than the value calculated by the “general code for design of highway bridges and culverts (China”. The Dieckmann index of bridge vibration is also related to lane number, and the vibration comfort evaluation is good in normal conditions. The relevant conclusions from parametric analyses have practical significance to dynamic design and daily operation of long-span continuous girder bridges in expressways. Safety and comfort are expected to improve significantly with further control of the vibration of vehicle–bridge system.

  17. On construction technique of arc model at box girder web%箱梁外腹板圆弧模施工技术

    Institute of Scientific and Technical Information of China (English)

    梁见

    2012-01-01

    Combining with the arc model construction of the continuous box girder web at Yijiang Bridge at Wuhu, the paper undertakes the mould installation by adopting various method according to the parameters of the web arc and the field fact, and mainly introduces the technique, including the making and the consolidation of the box girder arc models with two different parameters, so as to have better reference and direction for the similar bridge construction.%结合芜湖弋江桥连续箱梁外腹板圆弧模施工技术,根据外腹板圆弧半径大小,结合现场实际情况,通过采取不同方法进行模板制安施工,详细介绍了两种不同圆弧半径的箱梁圆弧模板的制作、加固等技术,对同类型桥梁施工具有较强的借鉴和指导作用。

  18. Coupled Vibration of Long-Span Railway Curved Girder Bridges and Vehicles

    Institute of Scientific and Technical Information of China (English)

    Shan Deshan; Li Qiao

    2005-01-01

    The structure of a long curved girder bridge is represented with a three-dimensional curved finite element model. Each 4-axle vehicle is modeled by a dynamic system of 35 degrees of freedom. The random irregularities of the track are generated from a power spectral density function under the given track condition. The dynamic interaction between the bridge and train is realized through the contact forces between the wheels and track. Then based on these models, the coupled equations of motion are solved by applying the time-integration and iteration techniques to the coupled system. The proposed formulation and the associated computer program are then applied to a real curved girder bridge. The dynamic responses of the bridge-vehicle system and the derailments and offload factors related to the riding and running safeties of vehicles are computed. The results show that the formulation presented in this paper can well predict dynamic behaviors of both bridge and train with reasonable computation efforts.

  19. Effect of nonlinearity of restrainer and supports on the elasto-plastic seismic response of continuous girder bridge

    Directory of Open Access Journals (Sweden)

    Wang Changfeng

    2014-10-01

    Full Text Available During an earthquake, the nonlinearity of the bridge structure mainly occurs at the supports, bridge piers and restrainers. When entering nonlinear stage, members of the bridge structure affect the elasto-plastic seismic response of the whole structure to a certain extent; for multi-span continuous bridges, longitudinal restrainers can be installed on the movable piers to optimise the distribution of seismic force and enable the movable piers to bear a certain amount of seismic effect. In order to evaluate the effect of nonlinearity of restrainer and supports on the elasto-plastic seismic response of continuous girder bridge, analytical models of continuous girder bridge structure considering the nonlinearity of movable supports, restrainers and bridge piers were built and the nonlinear time history analysis was conducted to evaluate the effect of nonlinearity of restraining devices and supports on the elasto-plastic seismic response of continuous girder bridge. Relevant structural measures and recommendation were made to reduce the seismic response of the fixed piers of the continuous girder bridge.

  20. Shear and shear friction of ultra-high performance concrete bridge girders

    Science.gov (United States)

    Crane, Charles Kennan

    Ultra-High Performance Concrete (UHPC) is a new class of concrete characterized by no coarse aggregate, steel fiber reinforcement, low w/c, low permeability, compressive strength exceeding 29,000 psi (200 MPa), tensile strength ranging from 1,200 to 2,500 psi (8 to 17 MPa), and very high toughness. These properties make prestressed precast UHPC bridge girders a very attractive replacement material for steel bridge girders, particularly when site demands require a comparable beam depth to steel and a 100+ year life span is desired. In order to efficiently utilize UHPC in bridge construction, it is necessary to create new design recommendations for its use. The interface between precast UHPC girder and cast-in-place concrete decks must be characterized in order to safely use composite design methods with this new material. Due to the lack of reinforcing bars, all shear forces in UHPC girders have to be carried by the concrete and steel fibers. Current U.S. codes do not consider fiber reinforcement in calculating shear capacity. Fiber contribution must be accurately accounted for in shear equations in order to use UHPC. Casting of UHPC may cause fibers to orient in the direction of casting. If fibers are preferentially oriented, physical properties of the concrete may also become anisotropic, which must be considered in design. The current research provides new understanding of shear and shear friction phenomena in UHPC including: (1) Current AASHTO codes provide a non-conservative estimate of interface shear performance of smooth UHPC interfaces with and without interface steel. (2) Fluted interfaces can be created by impressing formliners into the surface of plastic UHPC. AASHTO and ACI codes for roughened interfaces are conservative for design of fluted UHPC interfaces.(3) A new equation for the calculation of shear capacity of UHPC girders is presented which takes into account the contribution of steel fiber reinforcement. (4) Fibers are shown to preferentially

  1. 连续箱梁的日照温差应力计算研究%Study on Calculation of Sunshine Thermal Stress in Continuous Box-girders

    Institute of Scientific and Technical Information of China (English)

    陈权; 王丽娟; 张元海; 诸昌钤

    2009-01-01

    According to the harmonious condition of deformation and the assumption of plane section, the general formula for calculating sunshine thermal stress of continuous box girders was derived. Then based on the existing experimental results and the modes of sunshine thermal gradients in the present code for design of railway and highway bridges, the practical calculating formula of thermal stress was presented. The method and formula for calculating secondary thermal bending moment were provided tnnzekew continuous box girders based on the three-moment equation of skew continuous beam. The corresponding programmaing was fulfilled. The thermal stresses in figh and skew continuous box girders were calculated through engineering practice and good agreement was achieved compared with those of ANSYS calculation. The longitudinal distribution pattern of the thermal stress in continuous box girder bridges was ascertained. It is put forward that (1) much attention should be paid to the checking calculation for nonnal stress and crack resistance at midspan cross-section of central span in the design of prestrssed concrete continuous box girder bridges; (2) the checking calculation for crack resistance of inclined cross -section near gravity axis in internal support area should also be treated seriously.%根据变形协调条件及平截面假定,首先推导了连续箱梁日照温差总应力的一般公式,并针对试验观测资料及我国铁路桥梁和公路桥梁设计规范中的不同日照温差梯度模式,给出了温度应力的实用计算公式.为了能够进一步应用于斜交连续箱梁,以斜交连续梁的三力矩方程为基础,给出了温度次弯矩的计算方法及公式.编制了相应温度应力分析程序,结合工程实例分别对正交和斜交连续箱梁的温度应力进行了计算分析,并与ANSYS有限元计算结果进行对比.通过分析连续箱梁日照温差应力沿梁跨方向的分布规律,提出在设计预应力混凝

  2. The Compare Between Steel Box Girder And Steel Truss In City Overpass%钢箱梁及钢桁架城市人行天桥对比分析

    Institute of Scientific and Technical Information of China (English)

    范旭辉

    2012-01-01

    Steel box girder bridges are widely used in our city pedestrian bridge and it has the characteristic such as linear appearance and easy factory prefabricated construction. However, due to the need to control the vertical nat- ural vibration frequency, the box girder general beam steel is too high. As a result the steel truss bridge in the city pedestrian bridge is also a widely the popularity of the bridge type. The particle compares among the same span of two bridge type comprehensive comparison of the amount of structural steel, vertical natural frequency, constructa- bility, stairways climbed higher.%钢箱梁桥在我国城市人行天桥中应用广泛,其优点是线型美观,工厂预制装配式施工方便等。然而由于需要控制竖向自振频率,钢箱梁一般梁高过高,造成压抑感强,两侧梯道过长等缺点也不容忽视,因此钢桁架桥在城市人行桥中也是一种可以广泛普及的桥型,本文对相同跨径的两种桥型就结构用钢量、竖向自振频率、施工性、梯道爬高等方面进行了综合对比。

  3. Stress analysis of box girders with corrugate steel webs under distorsion%波形钢腹板箱梁畸变应力分析

    Institute of Scientific and Technical Information of China (English)

    杨丙文; 黎雅乐; 万水; 张建东

    2011-01-01

    According to mechanical characteristics of box girders with corrugated steel webs and theory of box girders, the warping normal stress of box girders with corrugated steel webs caused by distortion is studied. Considering that corrugated webs have fold effects, the corrugated webs are regarded as an orthotropic plate. Distortion governing differential equations of box girders with corrugated steel webs are derived under the equilibrium relation of plane force system within them. Their distortion angle and distortion bimoment are obtained using the beam elastic foundation (BEF) method , and then the longitudinal distortion stress is obtained. An analytical example is given to compare two types of box girders, concrete box girders and box girders with corrugated steel webs. The results of the example demonstrate that the box girders with corrugated steel webs have less lateral frame stiffness than concrete ones; thus, the distortional warping normal stress of box girders with corrugated steel webs is larger than that of concrete box girders.%在箱梁理论的基础上,根据波形钢腹板箱梁的力学特性,对波形钢腹板箱梁由畸变引起的翘曲正应力进行了研究.考虑到波形钢腹板具有褶皱效应,把波形钢腹板看作正交异性板,利用波形钢腹板箱梁中各板元平面力系的平衡关系,推导出波形钢腹板箱梁的畸变控制微分方程.采用弹性地基梁法解出波形钢腹板箱梁的畸变角和畸变双力矩,最终得到纵向畸变正应力.通过算例对比分析相同截面的波形钢腹板箱梁和混凝土箱梁的畸变翘曲正应力,计算结果表明,波形钢腹板箱梁相对普通混凝土箱梁的横向框架刚度较小,因此由畸变产生的翘曲正应力大于混凝土箱梁的畸变翘曲正应力.

  4. Nonlinear Stability Analysis of a Composite Girder Cable-Stayed Bridge with Three Pylons during Construction

    Directory of Open Access Journals (Sweden)

    Xiaoguang Deng

    2015-01-01

    Full Text Available Based on the nonlinear stability analysis method, the 3D nonlinear finite element model of a composite girder cable-stayed bridge with three pylons is established to research the effect of factors including geometric nonlinearity, material nonlinearity, static wind load, and unbalanced construction load on the structural stability during construction. Besides, the structural nonlinear stability in different construction schemes and the determination of temporary pier position are also studied. The nonlinear stability safety factors are calculated to demonstrate the rationality and safety of construction schemes. The results show that the nonlinear stability safety factors of this bridge during construction meet the design requirement and the minimum value occurs in the maximum double cantilever stage. Besides, the nonlinear stability of the structure in the side of edge-pylon meets the design requirement in the two construction schemes. Furthermore, the temporary pier can improve the structure stability, effectively, and the actual position is reasonable. In addition, the local buckling of steel girder occurs earlier than overall instability under load in some cable tension stages. Finally, static wind load and the unbalanced construction load should be considered in the stability analysis for the adverse impact.

  5. Discuss the Full Framing Construction of Cast-in-place Box Girder%浅谈现浇箱粱满堂支架搭设施工

    Institute of Scientific and Technical Information of China (English)

    黄亮

    2013-01-01

    在进行桥梁上部结构的箱梁现浇施工时,满堂支架法的应用已经非常普遍。但是在进行满堂支架法施工时,其施工事故发生的频率也比较高。如何有效提高满堂支架法的施工安全,是值得去深入探究的问题。%During conduct the box girder cast-in-place const-ruction of upper structure in bridge, the application of ful fra-ming method has become so common. But when making ful framing construction method, its construction has a high acide-nt frequency. It is worth to delve into the problem of how to i-mprove the method of ful framing construction safety.

  6. Proposal and study of a long-span composite cable-stayed bridge with new hybrid girder; Atarashii gosei kozo shuketa wo mochiita chodai fukugo shachokyo no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, K.; Hishiki, Y.; Furuichi, K. [Kajima Corp., Tokyo (Japan)

    1999-09-30

    A hybrid or mixed structure (composite structures) are a matter of increasing concern which takes in each advantage of steel and concrete. A field of bridges is no exception, with the plan and construction carried out for the new type of composite bridge, such as a composite cable-stayed bridge and a composite extra dose bridge as a long span bridge, and a composite truss bridge and a corrugated steel plate web bridge as a medium-span bridge, with technological development becoming active in this field. In such a technological trend, a hybrid two-girder structure was devised, a structure consisting of a concrete filled steel pipe for a girder and a precast (PC) floor plate for a floor board, as the girder structure of a long-span cable-stayed bridge in the subject research; also, applicability was examined using, as an example, the composite cable-stayed bridge with hybrid girders employed for the span. This paper reports the result of the analysis of the entire system, the analysis made for the purpose of examining the characteristic and the feasibility of this hybrid girder. The analysis revealed the structural feasibility of the long-span composite cable-stayed bridge using two hybrid girders of concrete-filled steel pipes thus devised. (NEDO)

  7. Perpendicular construction of bridge girder for long span suspension bridge under a rapid stream; Kyuchoryuka ni okeru chodai tsuribashi no hokoketa chokka tsuri koho no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Hirayama, J.; Sakamoto, M.; Nakao, T.; Koga, N. [Honshu-Shikoku Bridge Authority, Tokyo (Japan)

    1996-06-20

    Perpendicular construction of bridge girder for a long span suspension bridge, which is to be constructed over the Kurushima Channel, an international route, has been investigated. For the construction of suspension bridge over channels, the overhang construction is generally employed. Bridge girder perpendicular construction, in which unit girder block is lifted from a carrier barge and directly constructed by means of lifting beams located at main cable, is a superb method in terms of cost, time, and safety. It is necessary to stay the carrier barge during the anchoring of girder block and lifting beams. Mooring of the carrier barge is required under a rapid stream, which results in the trouble of under way ships. A propulsion positioning system has been developed for the bridge girder carrier barge, by which the position/propulsion of four thrusters equipped at each corner of the barge can be automatically controlled. Thus, the perpendicular construction of bridge girder has been developed, in which mooring is not required even under the rapid stream. The position of barge can be maintained within a range of {plus_minus}2.5 m even under a rapid stream with a speed of 3 kn. The quick joint can be certainly connected for about one minute in the horizontal movement within {plus_minus}2.5 m and vertical movement within 0.5 m. For this perpendicular construction, the construction time can be shortened to around 16 to 17 minutes, which has been usually taken for three hours. 2 refs., 17 figs., 4 tabs.

  8. Double Girder Bridge Crane with Double Cycling: Scheduling Strategy and Performance Evaluation

    Directory of Open Access Journals (Sweden)

    Dandan Wang

    2014-01-01

    Full Text Available This paper introduces a novel quay crane design, double girder bridge crane (DGBC. DGBC is capable of handling containers of two adjacent bays simultaneously, avoiding crane collisions, saving travelling and reposition cost, and eventually improving terminal efficiency. This problem is formulated as a resource-constrained project scheduling with objective to minimize the maximum completion time. A two-stage heuristic algorithm is proposed in which an operating sequences on each bay is obtained by double cycling, and the integrated timetable for both bays is constructed by solving resource conflicts using the proposed minimum cost strategy. We examine effectiveness and performance of applying DGBC with double cycling. A case study is presented to illustrate how DGBC works with the two-stage method. Three extreme cases with respective conflict types are investigated to develop the performance bounds of DGBC with double cycling. The results show that DGBC can significantly improve terminal productivity, and outperforms single girder crane in both makespan and the lift operation percentage. The highest DGBC efficiency does not require maximum double cycles in two bay schedules; rather the integrated timetable for two bays is the main contribution to the DGBC performance as it yields better cooperation between two spreaders and the driver.

  9. Effect of sensor placement on operational modal analysis of steel girder bridges

    Science.gov (United States)

    Whelan, Matthew J.; Gangone, Michael V.; Janoyan, Kerop D.

    2011-04-01

    With the advent and development of low-cost wireless structural health monitoring systems, the task of routinely assessing the in-service condition of highway bridges through distributed sensor-based measurements is an increasingly feasible component of bridge safety and management practice. Bridge monitoring encompasses placement of often a limited number of distributed sensors across a relatively large and complex structural system. Consequently, the selection of proper sensor locations is imperative to extraction of the most value from the recorded measurements. An experimental investigation is presented wherein sensor placement on the superstructure girders or primary beams is contrasted to the response measured on the surface of the bridge deck. The effect on the dataset richness, as evidenced by the modal content, is presented and conclusions regarding optimal placement for this structure type are presented. To affirm the plausibility of the observed responses and conclusions drawn, a finite element analysis is also performed on a model developed from the as-built drawings.

  10. Study on Fatigue Behavior of Anchorage of Cable and Girder of Long Span Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A full scale model test is done and a FEM model is established toinvestigate the fatigue behavior of the Nancha cable-stayed bridge of the Nanjing Second Yangtz River Bridge, a long span steel bridge with a main span of 628 m. The results of test and FEM are analyzed and compared. It is shown that they are in good agreement. It is verified that the fatigue characteristic of the anchorage structure of cable and girder of the bridge satisfies the requirements specified by Chinese, British and American codes.

  11. Full scale test of a SSP 34m box girder 1. Data report; Reinforced glass fiber/expoxy used in wind turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Find M.; Branner, K.; Nielsen, Per H. (and others)

    2008-03-15

    This report presents the setup and result of a full-scale test of a reinforced glass fibre/epoxy box girder used in 34m wind turbine blade. The tests were performed at the Blaest test facility in August 2006. The test is an important part of a research project established in cooperation between Risoe DTU, the National Laboratory for Sustainable Energy at the Technical University of Denmark -, SSP-Technology A/S and Blaest (Blade test centre A/S) and it has been performed as a part of Find Moelholt Jensen's PhD study. This report contains the complete test data for the final test, in which the box girder was loaded until failure. A comprehensive description of the test setup is given. This report deals only with tests and results. There are no conclusions on the data in this report, but references are given to publications, where the data are used and compared with FEM etc. Various kinds of measuring equipment have been used during these tests: acoustic emission, 330 strain gauges, 24 mechanical displacement devices and two optical deformation measuring systems. The mechanical displacement devices measured both global (absolute) and local (relative) deflection and the optical systems measured surface deformation. A prediction was made on the location of the failure of the girder. At this location the majority of the measuring equipment was concentrated. The prediction was proved to be correct and valuable information of the behaviour of the box girder prior to failure was obtained. The experimental investigation consisted of the following load configurations: -Flapwise bending -Torsion Ultrasonic scanning of the box girder was performed before, during and after the test the box girder. This was done to investigate whether the girder was damaged by the load or imperfection (productions defects) growth. (au)

  12. A compilation of research on self-consolidating concrete for prestressed bridge girders

    Science.gov (United States)

    Torres, Eduardo S.

    This thesis is composed of three research papers, for each paper a separate chapter is used, which investigates various aspects for the production of SCC utilizing materials available in the state of Wisconsin. Chapter one provides a summary of the current state-of-the-art and practice of technical documentation and specifications related to material properties and test methods for prestressed SCC bridge girders. Chapter two provides an experimental program designed to investigate the effect of material constituents on performance of SCC mixtures. From this experimental program specific mixture parameters were recommended for the application of SCC in Wisconsin DOT projects. Finally, chapter three consisted in monitoring samples of five SCC mixtures batched at three different precast plants from Wisconsin. Creep and shrinkage readings were taken for a period of 112 days to investigate the effect of specific mixture parameters of selected mixtures with performance desired by the Wisconsin DOT and precast plants. (Abstract shortened by ProQuest.).

  13. Performances of super-long span prestressed cable-stayed bridge with CFRP cables and RPC girder

    Institute of Scientific and Technical Information of China (English)

    Fang Zhi; Fan Fenghong; Ren Liang

    2013-01-01

    To discuss the applicability of advanced composite carbon fiber reinforced polymer (CFRP) and ultra-high performance concrete reactive powder concrete (RPC) in super-long span cable-stayed bridges , taking a 1 008 m cable-stayed bridge with steel girders and steel cables as an example,a new cable-stayed bridge in the same span with RPC girders and CFRP cables was designed,in which the cable’s cross section was determined by the principle of equivalent cable capacity and the girder’s cross section was determined in virtual of its stiffness, shear capacity and local stability. Based on the methods of finite element analysis,the comparative analysis of these two cable-stayed bridge schemes about static performances,dynamic performances,stability and wind resis-tance behavior were carried out. The results showed that it was feasible to form a highly efficient,durable concrete cable-stayed bridge with RPC girders and CFRP cables and made its applicable span range expand to 1 000 m long around.

  14. Research on temperature field and temperature stress of prestressed concrete girders

    Directory of Open Access Journals (Sweden)

    Chen Cheng

    2011-02-01

    Full Text Available This paper introduces the establishment and simplification of the temperature field and the general calculation method of temperature stress of the prestressed concrete box girders. Three kinds of sunshine temperature gradient models were loaded to a real bridge respectively, and got stress and displacement curves. Research data of several prestressed concrete box girders were selected from different regions of China to compare the relative error of the calculated and measured value. We indicate that the study of temperature field and thermal stress of prestressed concrete box girders is necessary, and will help engineers to solve the problem in structure design.

  15. Experimental Study on Structure-Borne Noise of Railway 32 m Simply-Supported Concrete Box-Girder%铁路32 m混凝土简支箱梁结构噪声试验研究

    Institute of Scientific and Technical Information of China (English)

    李小珍; 张迅; 刘全民; 张志俊; 李亚东

    2013-01-01

    以32 m单线和双线单室混凝土简支箱梁为对象,通过噪声试验、结构有限元和声学有限元分析,研究箱梁结构噪声的声辐射特性、峰值频率产生的原因及评价方法.结果表明:列车通过桥梁时,离箱梁表面较远处的噪声级起伏不大,可采用稳态算法简化分析;混凝土箱梁的结构噪声主要分布在250 Hz以下,且随频率的增加而迅速衰减,因此理论预测时可将250 Hz作为截止频率;单线和双线箱梁的2个噪声峰值频率分别为63和160 Hz,以及50和315 Hz,二者均在第1个峰值频率处达到最大声压级,且此峰值频率处的噪声具有明显的有调性;不同箱室尺寸箱梁的结构噪声声辐射差异较大,车速并不是噪声的第一决定因素;混凝土箱梁结构噪声的峰值频率出现在声辐射效率和振动响应均较大处,因此应避免结构振动模态和空腔声学模态重合而导致空腔共鸣引起的噪声被放大;建议修订铁路噪声相关规范时,考虑混凝土箱梁低频结构噪声的危害.%Based on the study objects of single-and double-track simply-supported concrete box-girders with only one cell and a span of 32 m,this paper investigated the sound radiation characteristics of structure-borne noise,reasons leading to peak frequency and evaluation methods by field measurements,structural and acoustical finite element analysis.The results show that:during a train runs across bridge,the noise far away from the box-girder surface fluctuates slightly,which means that simplified steady-state acoustic analysis is feasible; structure-borne noise from concrete box-girder dominates in the frequency lower than 250 Hz and decreases rapidly with increasing frequency,accordingly,250 Hz can be regarded as the upper limiting frequency for theoretical prediction; the two frequencies of peak noise of single-and doubletrack box-girder are 63 and 160 Hz,as well as 50 and 315 Hz,respectively,and the noise reaches

  16. Time-domain analysis of wind-induced buffet and wind-resistant measures for cable-stayed bridge with steel box girder at construction stage%大跨度钢箱梁斜拉桥施工过程风致抖振时域分析及抗风措施

    Institute of Scientific and Technical Information of China (English)

    张茜; 周绪红; 狄谨; 王继承

    2013-01-01

    以杭州湾跨海大桥北通航孔斜拉桥为背景,采用ANSYS有限元分析软件对其施工中最大双悬臂及最大单悬臂状态进行了风致抖振响应时域分析.采用谐波合成法进行了随机风场模拟,对塔、梁和索承受的风荷载分别进行了简化,并给出了静风力、抖振力和自激力的时域表达式及自激力在ANSYS中的实现方法;采用“鱼骨式”模型作为斜拉桥主梁的计算模型,分析考虑了结构的几何、气动非线性.分析结果表明:在施工阶段设计风荷载下,主梁悬臂端及塔顶处位移响应较小,风荷载效应与恒载效应组合后,塔根部截面最大拉应力为0.707 MPa;根据抖振响应分析结果和其他因素综合考虑,对杭州湾跨海大桥北通航孔斜拉桥提出了施工过程中有效可行的抗风措施.%Based on the project of north channel cable-stayed bridge of Hangzhou Bay Sea-crossing Bridge, the time-domain analysis of wind-induced buffet was carried out under the double and single jib condition by ANSYS. The random wind field was simulated by WAWS. Buffeting wind loads, which were exerted on tower, girder and cables, were simplified separately. The time-domain expressions of static wind force, buffeting force and full coupled auto-excited force, and how to exert the full coupled auto-excited force in ANSYS were proposed in this paper. Single beam elements were adopted to proceed the time-domain analysis, and the geometric and aerodynamic nonlinear of the structure was considered. Time-domain analysis results show that under the design wind loads at construction stage, the displacement response is smaller at the cantilever end of main girder and the top of pylon. The maximum tensile stress of the section at the root of pylon is 0. 707 MPa after combination of wind loads and dead loads. The wind resistance measures are suggested based on the results of the time-domain analysis and the influence of other factors. 3 tabs, 7 figs, 10

  17. Construction of stiffening girder for Akashi straits bridge. Installation with use of latest bridging technology; Akashi kaikyo ohashi hoko keta kasetsu koji. Saishin kakyo gijutsu wo kushishite kasetsu

    Energy Technology Data Exchange (ETDEWEB)

    Oe, S. [Honshu-Shikoku Bridge Authority, Tokyo (Japan)

    1996-05-25

    The Akashi straits bridge is the Kobe-Naruto route of the bridge connecting Honshu and Shikoku; the bridge links Kobe in Hyogo prefecture with Awaji Island and, when completed, it will be a 3-span 2-hinge suspension bridge with the longest center effective span in the world. This report centers on the outline of the construction of stiffening girders for the Akashi straits bridge and especially on the characteristics of the engineering method newly employed. As the method of installing the stiffening girders, an overhang installation of face bars was employed which was a time-tested method. As the installing direction of the side spans, it was decided to install them from the anchorage to the tower. At the beginning, six large block installations were performed. A special balance was developed for the installation of short hanger parts for the purpose of enhancing safety and reduction in the process. A rubber-tired transporting truck was adopted for transporting members of framework on the bridge. GPS survey was used as a method for surveying the configuration. The subject engineering method was based on the construction of suspension bridge stiffening trusses in the past Honshu-Shikoku connecting bridge and reinforced with the improvements as above. Since the bridge is in the middle of construction, a subsequent report will hopefully be made on the actual results of the installation and the spanning after the closure. 8 figs., 2 tabs.

  18. Design and Analysis of Simple Supported Box Girder on Ballastless Single Track of High Speed Railway%高速铁路无砟轨道单线简支箱梁结构设计与分析

    Institute of Scientific and Technical Information of China (English)

    杨鹏健

    2015-01-01

    结合350km/h高速铁路常用跨度无砟轨道单线简支箱梁通用参考图设计,介绍该箱梁在梁高、桥面宽度、二期恒载、支座横向中心距、梁端构造等方面的受力分析以及从景观性、经济性方面阐述腹板斜率、外轮廓圆弧倒角等细部构造,并通过计算分析选定合理值。%Based on the General Reference Drawing for Simple Supported Box Girder with Common Span on Balastless Single Track for 350 km/h High Speed Railways, this paper focuses on the analysis of stresses with respect to girder height, bridge deck width, secondary dead load, transverse center distance of bearing, girder end structure, and web slope and arc chamfering of outer contour and other micro structures are illustrated in terms of outlook and economy. Furthermore, reasonable values for these parameters are determined through calculation.

  19. 预应力混凝土连续宽箱梁偏载系数研究%Research of Unbalanced Coefficient of Prestressed Concrete Continuous Wide Box Girder

    Institute of Scientific and Technical Information of China (English)

    辛慧; 赵玲

    2014-01-01

    Taking prestressed concrete single box multi-cells continuous wide box Girder Bridge at Tongqi street Nantong city as the background, the paper establishes entity unit spa-tial finite element models. There is a comparison between calculated value which is got though increasing the coefficient of normal stress in each location point of box Girder min-span calculation section and the value calculated by common sim-plified method. The paper discusses the feasibility of the simp-lified calculation method and offers a reference for the similar engineering design.%以南通通启路高架工程的预应力混凝土单箱多室连续宽箱梁桥为背景,建立实体单元空间有限元模型,将箱梁跨中截面各位置点的正应力增大系数计算值与常用简化计算方法所得值进行对比,探讨简化计算方法的可行性,供同类工程设计参考。

  20. Study of Treating Schemes For Long-Term Downwarping Deterioration of Main Girder of A Bridge%某桥主梁长期下挠病害处治方案研究

    Institute of Scientific and Technical Information of China (English)

    蔡巍; 江湧; 陈波

    2015-01-01

    某桥主桥为主跨400 m的斜拉桥,1995年建成通车。在交通量激增、荷载超载、预应力损失等因素作用下,部分桥跨主梁呈现下挠加剧,主梁混凝土出现剥落、露筋及开裂等病害。为抑制主梁下挠不断发展的趋势,采用结构自重减载方式(将混凝土人行道板置换为轻型钢人行道板)来部分减缓主梁下挠,并对箱梁顶板底面粘贴碳纤维布进行加固。采用有限元软件建立主桥模型,计算结构自重减载及粘贴碳纤维布对改善主梁下挠的作用效应。结果表明,将混凝土人行道板置换成轻型钢人行道板后,主梁下挠程度相对减小;碳纤维布与主梁共同参与受力,在一定程度上抑制了混凝土病害进一步发展,也避免了因混凝土开裂而造成的主梁下挠,验证了该加固方案的可行性。%A Bridge was opened to traffic in 1995 .Its main bridge is a cable‐stayed bridge with a main span of 400 m .According to the inspection report ,the downwarping of main girder in some spans had been exarcebated ,the main girder concrete began to spalling ,deteriations including con‐crete spalling ,reinforcement exposure and concrete cracking were also found ,the causes of which can be attributed to the surge of traffic ,over load and prestress loss .To curb the exarcerbation of main girder downwarping ,the way of relieving the self weight of the structure was used to partial‐ly slow down the main girder downwarping ,specifically by replacing the concrete slabs in the side‐walks by the ligh weight steel plates ,and the main girder was strengthened by gluing carbon fiber sheet on the base of the top plate of the box girder .The finite element software was used to estab‐lish the model of the main bridge ,to calculate the effect of structural self weight reduction and car‐bon fiber sheets strengthening on the enhancement of main girder downwarping .The results of the calculation indicate

  1. Design of Prestressed Concrete Box Girder Based on Life Cycle%基于全寿命周期的预应力砼小箱梁设计

    Institute of Scientific and Technical Information of China (English)

    余少华

    2013-01-01

    With the increasing age of bridge girders,performance degradation is an unavoidable phenomenon. In addition to the natural aging,the bridge performance degradation can be attributed to many factors,such as the bridge construction speed,short design cycle,the outdated design concepts,serious overload,lack of mainte-nance and so on. Therefore,it is significant to take into consideration the whole bridge life cycle in the scientific design of bridges. This study first collected the road area data of a newly built bridge,including environmental data,traffic data and other basic structure data,then divided the life cycle with reference to the bridge mainte-nance specification provisions of the management and maintenance unit,and finally analyzed the cycle cost. This preliminary study on the cycle life of commonly-used prestressed concrete box beam tries to provide some reference for the bridge design.%随着桥龄的增加,主梁性能老化是无法避免的现象。然而桥梁性能退化除了自然老化外,还与桥梁建设速度过快、设计周期短、理念陈旧、超载超限严重、疏于管养等因素有关。因此,科学的设计应把桥梁纳入全寿命周期考虑,本研究先搜集了新建桥梁公路干线所在地区的相关数据,如环境数据、交通量、基本及已建桥梁的结构数据,再结合管养单位执行的桥梁养护规范规定划分生命周期,进行周期成本分析,对常用的预应力砼小箱梁进行了全寿命周期设计的初步研究,以供同道参考。

  2. Geometry control of long-span continuous girder concrete bridge during construction through finite element model updating

    Science.gov (United States)

    Wu, Jie; Yan, Quan-sheng; Li, Jian; Hu, Min-yi

    2016-04-01

    In bridge construction, geometry control is critical to ensure that the final constructed bridge has the consistent shape as design. A common method is by predicting the deflections of the bridge during each construction phase through the associated finite element models. Therefore, the cambers of the bridge during different construction phases can be determined beforehand. These finite element models are mostly based on the design drawings and nominal material properties. However, the accuracy of these bridge models can be large due to significant uncertainties of the actual properties of the materials used in construction. Therefore, the predicted cambers may not be accurate to ensure agreement of bridge geometry with design, especially for long-span bridges. In this paper, an improved geometry control method is described, which incorporates finite element (FE) model updating during the construction process based on measured bridge deflections. A method based on the Kriging model and Latin hypercube sampling is proposed to perform the FE model updating due to its simplicity and efficiency. The proposed method has been applied to a long-span continuous girder concrete bridge during its construction. Results show that the method is effective in reducing construction error and ensuring the accuracy of the geometry of the final constructed bridge.

  3. 简直转连续斜箱梁桥单梁静载试验分析%PRESTRESSED REINFORCED CONCRETE SIMPLY SUPPORTED-CONTINUOUS BOX GIRDER SINGLE STATIC LOAD EXPERIMENT AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    张宏祥; 曹岩

    2013-01-01

    The single static load experiment is one of the important means to identify whether the bridges can be normal operationed or not during the normal operation period. We can detect whether single static structure performance meets the requirements of design documents and specifications and guarantee the safety of bridge after the completion of the bridge by the single static load experiment This paper unifies some prestressed reinforced concrete box example. It introduced the experiment examination content, the testing sequence, and the test result analysis of the prestressed reinforced concrete box girder simply supported - continuous static load testing. We can make a correct evaluation of prestressed reinforced concrete box girder, and provide the basis for future tests by summarizing the results of static loading test%单梁静载试验是检验桥梁在正常运营期间能否保证桥梁正常运营的一个重要手段,通过对单梁静载试验,检测单梁的结构性能是否达到设计文件和规范要求,保证成桥后桥梁的安全.结合某预应力混凝土斜箱梁实例,介绍预应力钢筋混凝土简直转连续单梁静载试验的检测内容、试验步骤和试验结果分析.总结单梁静载试验结果,对预应力钢筋混凝土简直转连续梁桥作出正确的质量评估,为以后的试验提供理论依据.

  4. Application of TMD in Large Span Steel Box Girder Footbridge%TMD在大跨径钢箱梁人行桥上的应用分析

    Institute of Scientific and Technical Information of China (English)

    苑翔

    2013-01-01

    This paper introduces the Tuned Mass Damper (TMD) composition and operation principle of the structure, comparison of advantages and disadvantages of TMD and other control of steel box girder footbridge vibration methods, and combined with the Mianyang No.1 bridge footbridge of Sichuan Province as an example, through the use of text and graph-table combination method, describes vividly the practical application of TMD in large span footbridge.%  介绍了质量调谐阻尼器(TMD)的结构组成以及工作原理,比较了TMD与其它控制钢箱梁人行桥振动方法的优缺点,并结合四川省绵阳市一号桥人行桥为工程实例,通过采用文字与图、表相结合的方式,形象地阐述了TMD在大跨径人行桥中的实际应用。

  5. On analysis of construction technique of prestressed concrete continuous box girder at curve section%谈曲线段预应力混凝土连续箱梁施工技术

    Institute of Scientific and Technical Information of China (English)

    贺喜萍

    2011-01-01

    结合具体工程实例,针对曲线段预应力混凝土连续箱梁施工技术进行了探讨,分别阐述了桥孔平面线形处理,弦弧差调整,墩顶连续端的处理,基桩坐标的确定等内容,以期指导今后同类工程,保证曲线段预应力混凝土箱梁平面线形美观。%Combining with the factual project examples,the paper explores the construction technique of the prestressed concrete continuous box girder at curve section,illustrates the treatment of the plane alignment of bridge holes,the adjustment of chord and arc difference,and the treatment of the continuous ends of pier tops,and the identification of the coordinate of foundation piles,so as to direct the similar projects and ensure the beauty of the plane lines of the prestressed concrete continuous box girder at curve section.

  6. Local stress analysis of flat steel box girder with circular arc lower desk%圆弧形底面扁平钢箱梁局部应力分析

    Institute of Scientific and Technical Information of China (English)

    饶瑞; 黄小峰; 林桢楷

    2011-01-01

    A flat steel box girder with circular arc lower desk was analyzed by two steps with two models, a whole bridge model established by larger scale elements and a segment model established by little scale elements. The whole bridge model was analyzed firstly to determine the boundary condition for the segment mod el. Then the local stress distributions of the upper desk and the lower desk were studied based on the segment model with the obtained boundary condition under the dead load and the living load. It is found that shear lag effects are significant in the upper and the lower desk and that effects of the ribs on the mid - span section are larger then that on the section near the pier. Comparisons of the lower desk stress dlstributions between two kinds of the flat steel box girder show that stress distributions of the girder with fold line lower desk are uniform than that of the girder with circular arc lower desk.%采用从整体到局部、从粗放到精细的两阶段两尺度分析方法,对国内首个圆弧形底面扁平钢箱梁在运营状态下的局部应力进行分析.用大尺度单元建立全桥模型,用小尺度单元建立梁段模型.通过分析全桥模型获得梁段模型的边界约束力.在此基础上,利用梁段模型研究钢箱梁在恒载和活载作用下项、底板的应力响应.研究表明:圆弧形底面扁平钢箱梁顶、底板均存在剪力滞现象,U肋对跨中截面应力分布的影响大于墩顶附近截面.圆弧形底面钢箱梁的底板正应力不均匀程度略大于折线形底面钢箱梁.

  7. Study on the Aerodynamic Characteristics of a Single-pylon Cable-stayed Bridge Girder by Numerical Simulation and Wind Tunnel Test

    Directory of Open Access Journals (Sweden)

    Longqi Zhang

    2014-09-01

    Full Text Available The wind induced vibration is one of the key technical problems for long-span bridge design. Therefore, a study on the aerodynamic characteristics of a single-pylon cable-stayed bridge girder is carried out in this paper. The aerostatic coefficient of the bridge girder, including both construction state and service state, is investigated by wind tunnel test with varying wind attack angle. Then based on the computational fluid dynamics (CFD method, the flow field around the bridge girder is visualized numerically. The risk of vortex-induced vibration (VIV is qualitatively evaluated by analyzing the flow features and by considering the Scruton number (Sc. Later a dynamic section model is tested in wind tunnel and the VIV phenomenon is observed subsequently. Results show that the aerodynamic stability is assured by the positive slope of the lift coefficient. The VIV response is influenced by the structural damping and the bridge accessory. The amplitude of VIV response can be lower by increasing the structural damping. The maintenance track rail of the bridge girder also does some good for suppressing the VIV as long as the track rail is located at the appropriate place.

  8. Matrix Analysis on Flexural Behavior of Thin-walled Box Girder%薄壁箱梁挠曲性能的矩阵分析

    Institute of Scientific and Technical Information of China (English)

    张元海; 林丽霞; 李乔

    2011-01-01

    On the basis of the shape function matrix which is established through assuming the homogeneous solution to the governing differential equation for shear lag of the thin-walled box girder as the element displacement function, the formula of the equivalent nodal force of the element under vertical concentrated loads is derived by applying the principle of virtual work. The reasonable warping displacement function of shear lag is proposed for the box girder with the twin-cell cross-section. The plexiglass model of the cantilever box girder with variable cross-sections is calculated, thus validating the effectiveness of the finite segment element in analysis of the box girder with variable cross-sections. The flexural behavior of the prestressed concrete continuous box girder with variable cross-sections is analyzed through a practical example. The results show as follows:The finite segment element has high computing efficiency for the box girder with variable cross-sections; under the action of vertical concentrated loads, the shear lag moment diagram of the box girder is a smooth curve and the absolute value of the shear lag moment is not greater than that of the bending moment at any cross-sections; the shear lag effect increases the mid-span deflection of the continuous box girder significantly, which shall be treated seriously in engineering practice.%在选取薄壁箱梁剪力滞控制微分方程的齐次解作为单元位移函数建立形函数矩阵基础上,运用虚功原理推导竖向集中荷载作用下单元等效节点力公式,提出双室箱梁的合理剪滞翘曲位移函数.通过对变截面悬臂箱梁有机玻璃模型进行计算,验证提出的梁段单元对分析变截面箱梁的有效性.结合实际箱梁算例,分析预应力混凝土变截面连续箱梁的挠曲性能.研究结果表明:所提出的梁段单元用于变截面箱梁分析时,具有较高的计算精度;在竖向集中荷载作用下,箱梁剪滞力矩图是一条

  9. Construction technology points for box-girder fabrication and installation engineering%箱梁预制与安装工程施工技术要点

    Institute of Scientific and Technical Information of China (English)

    李慧萍

    2011-01-01

    Taking He-Yun highway box-girder fabrication project as the example,it summarizes the construction technology points for box-girder fabrication and installation engineering,respectively describes the fabrication plant layout,steel reinforcement preparation,pre-stressed tension,duct jacking and other critical construction procedures and attentions,which has provided certain guidance for future similar project.%以河运高速公路箱梁预制项目为例,针对箱梁预制及安装工程施工技术要点进行了总结,分别阐述了预制厂的布置,钢筋加工,预应力张拉,孔道压浆等关键工序施工步骤及注意事项,为今后同类项目提供了一定指导。

  10. 钢桁腹预应力混凝土组合梁桥的剪滞效应%Study on Shear-lag Effect of Steel Truss-web and Pre-stressed Concrete Composite Girder Bridge

    Institute of Scientific and Technical Information of China (English)

    刘朵; 张建东; 刘钊

    2013-01-01

    The steel truss-web and pre-stressed concrete composite girder bridge consists of two parts :steel truss-web and top-and-bottom concrete board .Because the distribution of shear deformation is non-uniform ,the composite box girder bridge has the obvious shear-lag effect under longitudinal bending .Taking a steel truss-web and pre-stressed concrete composite girder bridge for example ,the shear-lag effect and the distribution law of effective width are analyzed by the fi-nite element model of space ,and the effects of top-and-bottom thickness and steel pipe thickness on the shear-lag effect are studied here so as to provide references for the similar design in the future .%钢桁腹预应力混凝土组合梁桥在截面形式上采用桁式腹杆和混凝土顶底板,由于剪切变形的不均匀性,使得组合箱梁在纵向弯曲时产生较为明显的剪滞效应。以某钢桁腹混凝土组合梁桥为例,利用空间实体模型分析了剪滞效应和有效宽度分布规律,并研究了顶底板厚度及钢管壁厚对剪滞效应的影响,为今后同类桥型的设计提供参考。

  11. General design of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Yuan Hong; Pei Minshan; Dai Jie; Xu Lin

    2009-01-01

    The main span of Sutong Bridge is a double-pylon, double-plane cable-stayed bridge with steel box girder, which has the world's longest central span of 1 088 m within cable-stayed bridges. To overcome problems caused by severe meteorological conditions, perplexing hydrological conditions, deep buried bedrock and higher navigation level, many new technics and methods were created. Keys including structural system, steel box girder, stayed cable, tower, pier, tower foundation, collision avoidance system, wind-resistance, seismic-resistance, structural nonlinear response and structural static stability were presented individually in this paper.

  12. 箱梁钢筋定位自动检测装置%The automatic detection device for box girder reinforced positioning

    Institute of Scientific and Technical Information of China (English)

    邵云

    2014-01-01

    In order to reduce or eliminate the box girder quality oroblems caused by box girder reinforced orotection layer and ore-stressed oosi-tioning network reinforced deformation and installation not in olace,this oaoer researched the reinforced oositioning of reinforced orotective layer and ore-stressed oositioning network in oost tensioned ore-stressed box beam construction orocess,designed a set of automatic detection each ten-sioned oositioning detection ooint tensioned whether accuracy oositioning or not and disolayed the tensioned oositioning automatic detection de-vice,solved the oroblem of reinforced oositioning detection.%为了减少或消除因箱梁钢筋保护层及预应力定位网钢筋形变和安装不到位而引起箱梁质量问题,对后张法预应力箱梁施工工艺中的钢筋保护层及预应力定位网的钢筋定位进行了研究,设计了一套能自动检测各检测点钢筋是否定位准确并显示的钢筋定位自动检测装置,解决了钢筋定位检测的问题。

  13. Assessment and Strengthening of a Fire Damaged Prestressed Concrete Continuous Girder Bridge%某预应力混凝土连续梁桥火损评估与加固

    Institute of Scientific and Technical Information of China (English)

    刘华; 高宗余; 刘其伟; 张军雷

    2015-01-01

    某大桥靠岛岸侧的5×35 m连续梁引桥于2012年某日凌晨3时左右遭受火灾。为恢复该桥的使用功能,针对火损后的桥跨进行现场检测,并结合火场温度和结构温度场的模拟分析,对结构的受损程度进行综合评定。结果表明箱梁表面有较大面积的混凝土崩落,且造成钢筋外露,受火灾影响最为严重的是内侧翼板处,因火损导致8根横向预应力钢绞线外露。在此基础上针对箱梁混凝土火损后剥落采取砂浆修补或灌注并结合粘贴锚固钢板的措施;针对翼板横向预应力火损采取增设钢结构隔板的措施;针对结构整体采用张拉粘贴预应力碳纤维板的措施进行维修加固。经试验评定,验证了加固方案实施后的桥梁承载能力得以恢复。%T he 5 × 35‐m span continuous girder approach bridge of a bridge on the island bank side caught fire at about 03 :00 in the early morning in a day in 2012 .To restore the operational function of the bridge ,the fire damaged spans of the bridge were inspected in the field ,the fire temperatures and temperature fields of the structure were simulated and analyzed and the damage degrees of the structure were comprehensively assessed .The results of the assessment show that rather great area of concrete spalling occurs on the surface of the box girder of the bridge and the concrete spalling causes the exposure of the reinforcement .The part of the box girder affected most severely by the fire damage is the inner side cantilever slab w here 8 transverse prestressing steel wire strands are exposed owing to the fire .According to the assessment ,the concrete spal‐ling of the box girder is repaired by the measure of plastering or grouting the cement mortar and binding the anchor steel plates .The damaged prestressing steel wire strands of the cantilever slab are repaired by the measure of adding the steel partition plates and the w hole structure is repaired and

  14. The delicate analysis of shear lag effect on trapezoidal box girders%梯形箱梁剪力滞后效应的精细化分析

    Institute of Scientific and Technical Information of China (English)

    甘亚南; 石飞停

    2014-01-01

    引入剪滞翘曲应力自平衡条件的影响,考虑了剪切变形和剪滞效应等因素,设置了三个不同的剪滞纵向位移差函数以准确反映梯形箱梁不同宽度翼板的剪滞变化幅度,提出了一种能对工程中常用箱梁静力学特性分析的精确解法。本文以能量变分原理为基础建立了薄壁箱梁的弹性控制微分方程和自然边界条件,获得了相应广义位移的闭合解。算例中,分析了不同荷载形式、跨宽比和悬臂板长度等因素对箱梁静力学特性的影响,结果显示出引入剪滞翘曲应力自平衡条件的必要性。%In consideration of self-equilibrium condition for shear lag warping stress ,shear deformation and shear lag effect ,three different longitudinal displacement difference functions are employed to accu-rately reflect the amplitude of change of shear lag in the trapezoidal box girders with various widths of wing slabs ,and a new warping displacement mode of trapezoidal thin-walled box girders is chosen to meet the axial self-equilibrium condition for corresponding stress ,a more accurate approach is proposed to analyze the mechanical characteristics of trapezoidal box girders generally used in engineering .Based on the minimum potential principle ,the governing differential equations and related natural boundary conditions are induced ,the closed-form solutions of generalized displacements are obtained .The varia-tions of stress of trapezoidal box girders ,caused by the change of factors such as self-equilibrium condi-tion ,type of loading and ratio of span and width are discussed ,the importance about the introduction of self-equilibrium condition is proved .

  15. 武黄客专700t预制简支箱梁架设施工技术%On construction technique for erection of 700 t prestressed simply supported box girder along Wuhan-Huangshi special passenger line

    Institute of Scientific and Technical Information of China (English)

    魏巍

    2011-01-01

    Taking the erection of 700 t prestressed simply supported box girder along Wuhan-Huangshi special passenger line as the example, the paper sums up the erection equipment and structure characteristic of the box girder and its performance, and illustrates the construction craft of the erection for the box girder and the key points for bearing' s perfusion, so as to accumulate relative experience and direct the engineering prac- tice.%以武黄客运专线700t预制简支箱梁架设为例,对箱梁架设设备及其结构特点和性能作了归纳,重点对箱梁架设施工工艺及支座灌注要点进行了阐述,以积累相关施工经验,指导工程实践。

  16. 铁路混凝土箱梁箱内空腔共鸣噪声及其影响研究%Study on Cavity Resonance Noise of Railway Concrete Box-Girder and Its Influence

    Institute of Scientific and Technical Information of China (English)

    张迅; 王党雄; 李小珍

    2015-01-01

    为探讨铁路混凝土箱梁箱内空腔共鸣噪声及其影响,以某客运专线32 m预应力混凝土简支箱梁为研究对象,开展实桥振动与噪声试验,分析箱梁振动与噪声的时域特性及频谱特性。采用有限元法建立三维空腔声模型,分析箱内空腔声模态与腔内噪声峰值的关联性。采用边界元法分别建立两端封闭与两端开口的箱梁声学模型,验证箱内空腔共鸣噪声的来源及其影响。结果表明:在特定行车速度下,箱内噪声出现“拍”现象,显著增大箱内噪声,瞬时最大声压可达40 Pa,峰值频率为75.0 Hz;箱内噪声的“拍”现象来源于顶板的振动噪声,顶板的振动峰值频率与箱内空腔垂向声模态频率吻合时,箱内噪声显著增大;由于梁缝的声泄漏特性,箱内空腔共鸣噪声在梁缝处衰减较大,但其对桥梁两侧总体噪声的影响不可忽略。%In order to study the cavity resonance noise of concrete box-girder and its influence,a field test con-cerning vibration and noise of a 32 m PC simply-supported box-girder was carried out,to investigate the time-domain characteristics and frequency spectrum characteristics of vibration and noise of the box-girder.A 3D cavity acoustical model was established based on FEM to analyze the correlation between cavity acoustic mode and cavity noise peak.Two acoustical models for box-girders with closed ends and open ends,were built based on BEM,respectively,to verify the source and influence of cavity resonance noise.Results showed that the“beat”wave phenomenon of cavity noise appeared under a specific train speed,significantly increasing the cavi-ty noise,with the transient maximum sound pressure of cavity noise reaching 40 Pa and the noise peak frequen-cy being 75.0 Hz;The “beat”wave phenomenon of cavity noise derived from the vibration of deck.When the peak vibration frequency of deck matched with the frequency of vertical acoustic modal of the cavity

  17. 箱型桥梁结构的面板声学贡献分析%Application of panel acoustic contribution theory in study of noise fro m simply -supprted box girder in high speed rail way

    Institute of Scientific and Technical Information of China (English)

    刘林芽; 付奇川; 邵文杰; 李纪阳

    2015-01-01

    Taking the high speed railway 32 m concrete simply -supported box bridge as the research object,the theses used finite element software to set up for high speed railway track -bridge analysis model.Then,based on the theory of vehicle -track -bridge coupling vibration,this paper analyzed the vertical vibration of the struc-ture of the bridge.A vertical vibration response was finally gotten as boundary conditions,which we use in the boundary element model of box girder structure noise prediction.At the same time,based on panel acoustic con-tribution analysis theory,the box beam body panel pressure contribution analysis and panel acoustic power analy-sis were done.In this way,we determined the largest position of body radiation noise for box beam .The results of the study show that if the train speeds up to 200 km /h on the elevated rail,box beam body radiation noise mainly occur within the range of 0 -100 Hz,of which 20 Hz and 42 Hz are prominent peak.Meanwhile,by the panel acoustic contribution analysis,we come to the conclusion that the part of main radiation noise comes from the box girder roof and the two flank flange panel.%以高速铁路32 m 混凝土简支箱型桥梁为研究对象,通过有限元软件建立了轨道-桥梁分析模型,采用车辆-轨道-桥梁耦合振动理论,分析了桥梁结构的竖向振动,并将得到的竖向振动响应作为边界条件,导入到箱梁边界元模型中预测箱梁结构噪声。同时基于面板声学贡献分析理论,进行了箱梁梁体的面板声压贡献分析和声功率贡献分析,确定箱梁梁体辐射噪声的最大部位。研究结果表明:列车以200 km/h 的速度运行在高架轨道上时,箱梁梁体辐射噪声主要集中0-100 Hz 范围内,其中在20 Hz 和42 Hz 左右有比较突出峰值。同时由面板声学贡献分析可知箱梁梁体主要辐射噪声的部位是箱梁的顶板和两侧翼缘板下面板。

  18. PC连续箱梁合龙束横向效应%Transverse Effect of Bottom Continuity Tendons in Continuous PC Box Girder

    Institute of Scientific and Technical Information of China (English)

    项贻强; 唐国斌; 朱汉华; 晁春峰

    2011-01-01

    Bottom continuity tendons induce transverse additive effect while providing longitudinal compression during the construction of PC box girder. Taking a cross-sea bridge for example, the mechanism of bottom continuity tendon is investigated. The transverse effect and parameters study are conducted through a refined model. It is illustrated that the state of bottom flange is in a dynamic changeable process during the tensioning of bottom continuity tendons, and the transverse effect caused by the tendons is much more than that by dead loading and other prestressing tendons. The transverse effect is more sensitive to alignment and thickness of the bottom flange, as well as concrete cover of the ducts. Finally, based on the simplified frame analysis, the design method is proposed by introducing prestressing effect simplified factor and duct modified factor.%PC连续箱梁合龙束张拉不仅使底板纵向受压,同时在横向产生附加效应;以某跨海大桥为例,对底板合龙束作用机理进行探讨,并通过精细有限元模型,对施工过程中合龙束的横向效应进行分析和参数研究;结果表明,合龙束张拉过程中底板横向应力处于动态变化过程,其横向效应远大于恒载和其它预应力作用结果,同时,合龙束的横向效应对底板的线形、厚度及孔道保护层较为敏感;最后,基于横向框架法,通过引入预应力效应简化系数和孔道修正系数,提出合龙束横向效应的简化计算方法.

  19. 弯扭耦合下曲线混凝土箱梁截面应力状态的受力机理分析%Analysis of Stress Mechanism of Cross Section of Curved PC Box Girder Under the Action of Bending-Torsion Coupling

    Institute of Scientific and Technical Information of China (English)

    何庆华; 卫星

    2013-01-01

    曲线箱形梁兼具弯梁桥与箱形梁两者的特点,由于曲率的影响,竖向荷载作用下曲线箱梁弯矩与扭矩互相耦合同时存在.根据国内外既有研究成果,对曲线箱形梁空间受力特点及影响因素进行了总结.以60m单跨单箱形截面曲线混凝土简支梁为例,利用有限元软件TDV建立空间板单元模型,分析自重作用下,不同曲线半径下主梁截面正应力及剪应力分布,根据弯曲变形与应变的关系,比较曲线梁桥与直线梁桥正应力横向分布规律,提出用应力增大系数来表征曲线内外侧弧长不同引起的应力变化.研究结果表明,除了受剪力滞后效应影响,曲线箱梁桥截面正应力分布还与内外侧弧长不等引起的应力增大系数有关.%Curved box girder has both characters of curved girder and box girder, and the coupling effect between bending moment and torsion moment caused by the curvature under vertical load should be taken into account. Based on research results of curved girder at home and abroad, the spatial mechanical characters and influencing factors of curved box girder were summarized in this thesis. Choosing a 60m single-span curved PC simply supported girder with single cell boxed cross-section as the example, spatial plate element models were established by TDV finite element software. Then the distributions of normal stress and shear stress of cross-section of main girder with different curve radius under the action of dead load were analyzed. Afterwards, according to the relationship between bending deformation and strains, and by comparing the transverse distributions of normal stress of curved bridge with that of straight bridge, the thesis put forward a view point that the stress variation caused by the arc length difference between the internal arc and external arc of the curve can be expressed by a magnification coefficient. Analysis results show that, except the effect of shear lag, the distributions of

  20. Main Girder Type Selection for Maputo Bridge in Mozambique Based on Sectional Model Wind Tunnel Test%基于节段模型风洞试验的莫桑比克马普托大桥主梁选型研究

    Institute of Scientific and Technical Information of China (English)

    周健; 樊泽民; 王骑; 孟令亮; 魏雪涛; 李元博

    2014-01-01

    为合理确定主跨680 m 的莫桑比克马普托大桥的主梁形式,利用节段模型风洞试验,分别研究了扁平钢箱梁、钢箱叠合梁和工字型叠合梁的气动性能。结果表明:扭转刚度较弱的工字型叠合梁颤振风速远低于检验风速,且涡激振动也不满足舒适性要求,在设计中不宜采用;钢箱叠合梁尽管颤振风速较高,但其在钢箱顶面凸起的混凝土桥面板会造成气流分离和漩涡脱落,可能存在较大涡激振动振幅的隐患,可在设计中选择性采用;扁平钢箱梁断面颤振临界风速高,且无明显涡激振动,为该大跨度悬索桥的优选主梁形式。试验结果还显示,若设置宽0.5 m 的风嘴导流板可进一步提高钢箱梁断面的颤振临界风速,但由于导流板直接影响造价并增加后期养护费用,而节段模型试验结果一般偏于保守,因此最后的取舍需要参考三维颤振计算或全桥气弹模型风洞试验结果。若在其斜腹板上外挂直径90 cm 的过桥水管,将显著弱化颤振性能和涡振性能,因此在设计中不宜采用。%To select a rational main girder type for the Maputo Bridge in Mozambique which is projected to have a main span of 680 m ,the aerodynamic behavior of three types of main girder ,in-cluding the flat steel box girder ,steel-concrete composite box girder and I-shaped composite girder were examined by the sectional model wind tunnel test .The results of the test indicate that the I-shaped composite girder with intrinsic low torsional stiffness is not a favorable solution in the de -sign ,for its flutter wind speed is much smaller than the testing wind speed and its vortex -induced vibration is not able to meet the requirements of physical and psychological comfort as well .The steel-concrete composite box girder can withstand higher flutter wind speed ,but the concrete deck slab humps on top of the steel box are prone to cause airflow

  1. Gust loading on streamlined bridge decks

    DEFF Research Database (Denmark)

    Larose, Guy; Mann, Jakob

    1998-01-01

    The current analytical description of the buffeting action of wind on long-span bridges is based on the strip assumption. However, recent experiments on closed-box girder bridge decks have shown that this assumption is not valid and is the source of an important part of the error margin...... of the analytical prediction methods. In this paper, an analytical model that departs from the strip assumption is used to describe the gust loading on a thin airfoil. A parallel is drawn between the analytical model and direct measurements of gust loading on motionless closed-box girder bridge decks. Empirical...

  2. Treatment Measures for Empty Bearing of Arc Steel Box Girder with Cross Slope for Rotating Structure%旋转结构找横坡弧形钢箱梁支座托空处理措施

    Institute of Scientific and Technical Information of China (English)

    李粤东; 夏崇滔; 张翼; 巫正伟

    2014-01-01

    钢箱梁结构因其自身的特性在市政工程建设得到大量运用,钢箱梁吊装施工中空间就位及空形态的控制问题较为突出,其中带纵坡的弧形钢箱梁通过旋转结构找横坡就使得钢箱梁在施工过程中整体空间形态要有控制技术难度更高,极易造成钢箱梁支座托空。该文结合工程实例,就有纵坡且旋转结构找横坡弧形钢箱梁吊装后产生支座托空的处理措施进行论述。%Steel box girder structure is widely applied nowadays for its virtues, but the controlling problems in space location and spatial form in its con-struction are severe, and the finding of cross slope through rotating structure by arc steel box girder with longitudinal slope renders controlling technology of steel box girder over spatial form harder, easily causing empty bearing of steel box girder. The treatment measures for such problem are presented in de-tail.

  3. Seismic Performance of Multi-Span RC Railway Bridges

    DEFF Research Database (Denmark)

    Georgakis, Christos; Barrau, Xavier

    2008-01-01

    Presently, there is no clear method for determining the optimal railway bridge design for a particular ground type and expected seismic intensity. Four main types of RC bridge dominate the current multi-span railway bridge design trends – the Simply Supported Beam, Continuous Box-Girder (CBG), CBG...

  4. Live-Load Testing Application Using a Wireless Sensor System and Finite-Element Model Analysis of an Integral Abutment Concrete Girder Bridge

    Directory of Open Access Journals (Sweden)

    Robert W. Fausett

    2014-01-01

    Full Text Available As part of an investigation on the performance of integral abutment bridges, a single-span, integral abutment, prestressed concrete girder bridge near Perry, Utah was instrumented for live-load testing. The live-load test included driving trucks at 2.24 m/s (5 mph along predetermined load paths and measuring the corresponding strain and deflection. The measured data was used to validate a finite-element model (FEM of the bridge. The model showed that the integral abutments were behaving as 94% of a fixed-fixed support. Live-load distribution factors were obtained using this validated model and compared to those calculated in accordance to recommended procedures provided in the AASHTO LRFD Bridge Design Specifications (2010. The results indicated that if the bridge was considered simply supported, the AASHTO LRFD Specification distribution factors were conservative (in comparison to the FEM results. These conservative distribution factors, along with the initial simply supported design assumption resulted in a very conservative bridge design. In addition, a parametric study was conducted by modifying various bridge properties of the validated bridge model, one at a time, in order to investigate the influence that individual changes in span length, deck thickness, edge distance, skew, and fixity had on live-load distribution. The results showed that the bridge properties with the largest influence on bridge live-load distribution were fixity, skew, and changes in edge distance.

  5. Experimental investigation on prestressed concrete slabs for two- or three-girders bridges; Shoshuketa kyoryoyo PC yukaban ni kansuru jikken kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, F.; Yabe, J.; Ogaki, K.; Sakugawa, K.; Ito, A.; Takeuchi, K.; Tomoda, T. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1996-01-20

    Rationalization and labor-saving in the construction of bridges are the pending problems arising from the shortage of skilled construction workers, shortened time usable for construction, and demand for lower cost. Under the circumstances, experiment and study were conducted about the PC slab for two- or three-girder bridges. On the assumption of a PC slab located between two main girders, the interval 6 meters long, specimens near the real size were subjected to experiments. Springs were attached to the free sides so that load tests might be conducted under boundary conditions equivalent to those of a finite continuous slab along the direction of the bridge length as in case of a real bridge. It was found that a partial slab model of limited dimensions was usable when a long span slab experiment was necessary. A PC slab, unlike an RC slab, regained its elastic behavior when the load was removed even after the appearance of cracks. Crack producing loads fell within the range which could generally be estimated by calculation, and the PC slab was capable of restoring its original state upon unloading even after the production of cracks. The PC slab, as compared with the RC slab, demonstrated a greater ultimate strength, but the strength was not affected by the size of the prestress. In case of a PC slab on a long span, the bend fracture precedes and the ultimate strength is determined by the bend strength. 9 refs., 9 figs., 5 tabs.

  6. 汽车炸弹钢箱梁内部爆炸局部破坏效应分析%Analysis on local damage of steel box girder under internal blast loading of vehicle bomb

    Institute of Scientific and Technical Information of China (English)

    姚术健; 蒋志刚; 卢芳云; 张舵; 赵楠

    2015-01-01

    采用ALE(Arbitrary Lagrangian Eulerian,ALE)多物质流固耦合算法,对汽车炸弹(TNT当量200 kg~1500 kg)在双层桥梁下层桥面典型位置爆炸的局部破坏效应进行了数值模拟,研究了内爆炸冲击作用下钢箱梁的响应过程、破坏模式、破坏参数及其主要影响因素。结果表明:破坏模式及破坏参数与爆炸位置和TNT当量密切相关,爆炸位置对桥梁主要受力体系的受损程度影响较为明显,加劲肋对其垂直方向的破口具有约束作用,箱体对冲击波的约束效应使破坏作用加剧。合理设置加劲肋、加强重要构件和设置防爆层等措施有利于提高桥梁结构抗爆能力。%The response process,failure modes and damage parameters of a double deck steel box girder subjected to internal blast loading of vehicle bombs (TNT equivalent 200kg&1500kg)were simulated by using the ALE (Arbitrary Lagrangian Eulerian)multi-material fluid-solid coupling arithmetic.In the simulation,three typical blast locations on the lower deck were considered.The results show that:the failure modes and damage parameters have a clear correlation with the TNT weight and blast location,and the explosion locations have strong effects on the damage degree of steel trusses. Stiffening ribs can restrict the crack in its vertical direction.The damage effects will be intensified by the restriction of the box-shaped girder.Some useful measurements were also proposed which can help engineers in bridge designing and protection consideration against possible explosion events.

  7. Evaluation on Impact Interaction between Abutment and Steel Girder Subjected to Nonuniform Seismic Excitation

    Directory of Open Access Journals (Sweden)

    Yue Zheng

    2015-01-01

    Full Text Available This paper aims to evaluate the impact interaction between the abutment and the girder subjected to nonuniform seismic excitation. An impact model based on tests is presented by taking material properties of the backfill of the abutment into consideration. The conditional simulation is performed to investigate the spatial variation of earthquake ground motions. A two-span continuous steel box girder bridge is taken as the example to analyze and assess the pounding interaction between the abutment and the girder. The detailed nonlinear finite element (FE model is established and the steel girder and the reinforced concrete piers are modeled by nonlinear fiber elements. The pounding element of the abutment is simulated by using a trilinear compression gap element. The elastic-perfectly plastic element is used to model the nonlinear rubber bearings. The comparisons of the pounding forces, the shear forces of the nonlinear bearings, the moments of reinforced concrete piers, and the axial pounding stresses of the steel girder are studied. The made observations indicate that the nonuniform excitation for multisupport bridge is imperative in the analysis and evaluation of the pounding effects of the bridges.

  8. 合蚌客专350km/h单线试验箱梁工艺试验研究%Study on Process Test for Box Girder of Hefei-Bengbu Dedicated Passenger Railway 350 km/h Single-Track Line

    Institute of Scientific and Technical Information of China (English)

    郭晓明

    2012-01-01

    时速350公里客运专线单线后张法单箱单室预应力混凝土简支箱梁属首次应用。为验证其各项指标,进行了4孔箱梁的试验工作;通过对箱梁的各项工艺试验进行研究,充分验证箱梁的设计。%The post-tensioning method single-cell pre-stressed concrete simple box girder for 350 km/h dedicated passenger railway single-track line is used for the first time.To verify its performance indexes,four-truss box girder test is carried out,studies on box girder process tests fully verify the design of box girder.

  9. 箱型梁附加挠度与剪力滞效应的一维有限元分析%One-dimensional finite element analysis on additional deflection and shear-lag effect of box-girders

    Institute of Scientific and Technical Information of China (English)

    杨绿峰; 周月娥; 曾有凤

    2013-01-01

    当前箱型梁剪力滞效应分析的一维离散有限元法对剪力滞函数的处理存在局限性,而且剪力滞系数难以准确反映翼缘截面剪力滞效应及其变化规律.为此,利用箱梁附加挠度代替剪力滞函数建立箱梁翼缘的纵向位移函数,并根据能量变分原理建立控制微分方程并识别了其中的待定参数.以箱梁挠度、附加挠度及其一阶导数作为单元节点位移参数,提出了箱型梁剪力滞效应分析的一维离散有限元法,给出了箱梁的自然边界条件和强迫边界条件.基于箱梁挠度和附加挠度定义了新的剪力滞系数,分析了不同支撑条件对箱型梁剪力滞效应的影响.算例分析证明了该方法的有效性,且具有较高的计算精度;与传统的基于应力的剪力滞系数相比,基于挠度的剪力滞系数能够更加准确地反映箱型梁截面的剪力滞效应及其分布规律.%The shear-lag function in one-dimensional finite element method for box-girders has no definite physical interpretation, and moreover the shear-lag coefficient can not reflect correctly the shear-lag effect and its variation along the axis of box girder. In order to circumvent these problems, the additional deflection function instead of the shear-lag function is incorporated in the longitudinal displacement of the flange of the box girder. The variational principle is employed to identify the undetermined constants in the longitudinal displacement function. Furthermore, the deflection, additional deflection and their first derivatives are adopted as nodal displacement parameters in the discreted finite elements of box-girder, leading to one-dimensional finite element method for the shear-lag effect of box girders. A new shear-lag coefficient is defined in terms of the deflection of the box-girder, based on which the shear-lag effect on box girders is analysed with different boundary conditions considered. Examples show that the shear

  10. 预应力活性粉末混凝土箱梁抗弯性能试验%Experiment on Flexural Behaviors of Prestressed Reactive Powder Concrete Box Girders

    Institute of Scientific and Technical Information of China (English)

    方志; 刘明; 郑辉

    2015-01-01

    In order to study the mechanical behavior of prestressed reactive powder concrete (RPC) box girders ,the flexural behavior tests of two prestressed RPC box girders were carried out .T he force characteristic of RPC box girders and the influence of transverse prestressing force to its flexural performance were studied .The results show that the prestressed RPC box girders display a good deformation capacity ,with a maximal deflection of 1/50 of its span .The crack width and the short‐time stiffness of the RPC box girders can be calculated according to the formula in Technical Specif ication for Fiber Reinforced Concrete Structures (CECS 38 :2004) , with a coefficient of 0 .4 and 0 .2 considering influence from steel fiber , respectively . The transverse prestressing force in the top plate of RPC box girders has little influence on the flexural bearing capacity , but the force can make a more uniform strain distribution of the compressive concrete so as to reduce the shear‐lag effect and increase the ductility of the specimen .By applying a transverse prestressing force of 2 .95 M Pa (only 3 .1% of the RPC prism compressive strength of 94 MPa) at the top plate ,the effective distribution width of box girder increases by 10% ,and ductility index of specimen increases by 3% .The calculated formula to evaluate the cracking moment and the ultimate moment of a prestressed RPC box girders is proposed and verified by the experimental results .%为研究预应力活性粉末混凝土(RPC )箱梁的正截面受力性能,进行了2片预应力RPC箱梁的抗弯性能试验,研究了RPC箱梁的受力变形特征以及顶板横向预应力对其抗弯性能的影响。结果表明:预应力RPC箱梁具有良好的变形能力,其极限变形可超过跨径的1/50;RPC箱梁正常使用阶段的裂缝宽度和短期刚度可参照《纤维混凝土结构技术规程》(CECS 38:2004)的相应公式计算,其中的钢纤维影响系数可分别取为0

  11. 覆膜竹胶模板在现浇箱梁施工中的应用%Application of Coated Bamboo Rubber Template in Situ Box Girder Construction

    Institute of Scientific and Technical Information of China (English)

    王培国

    2012-01-01

    The materials of coated bamboo rubber template is light, its processing and demolition is convenient, and it is easy to operate. So it is widely used in the external and internal model construction of situ box girder. This paper, combined with the actual situ box girder construction, discussed characteristics, scope, process, operation points of coated bamboo rubber template in more detail, for the reference in construction.%覆膜竹肢模板具有材质轻、加工及安拆方便、操作简便特点,广泛用于现浇箱梁外、内模施工,本文结合现浇箱粱施工实际,对覆膜竹胶模板的特点、适用范围、工艺流程、操作要点进行了较为详细的论述,以供施工参考.

  12. Vibration and Buckling of Web Plate of the Plate Girder

    OpenAIRE

    高橋, 和雄; 呉, 明強; 中澤, 聡志; 筑紫, 宏之

    1998-01-01

    The vibration and buckling of the web of the plate girder are studied in this paper. The small deflection theory of the thin plate is used. The finite strip method is employed to solve vibration and buckling of the plate girder. Natural frequenies of buckling properties are shown for various plate girder bridges.

  13. Construction technology of steel structure shelter with elevated platform arc variable-section box girder%高架站弧形变截面箱梁钢结构雨篷施工技术

    Institute of Scientific and Technical Information of China (English)

    王志峰

    2015-01-01

    Combining with urban rail transit steel structure shelter with variable section box girder as an example,the paper studies construction quality control and limited hoisting construction of steel structure shelter with elevated platform arc variable-section box girder,and solves difficul-ties occurring in quality control and field limitation hoisting process of variable section box girder installation,which has accumulated experience for similar engineering.%结合某市城市轨道交通变截面箱梁钢结构雨篷施工实例,对高架站变截面箱梁钢结构雨篷制作质量控制及场地受限吊装施工展开了技术研究,解决了变截面箱形梁制作安装过程中质量控制及场地受限时吊装过程中的难题,为其他类似工程积累了经验。

  14. Manufacture Process of Steel Box Girder for RP Gantry in Some Nuclear Power Station%某核电站RP龙门架箱形钢结构梁制作工艺

    Institute of Scientific and Technical Information of China (English)

    展之芳

    2014-01-01

    In steel structure project, fabrication process of steel box girder is complex, so it is difficult to control welding deformation. This paper introduced the fabrication process of steel box girder for RP gantry in nuclear power station from the material, assembly, welding and correction. The fabrication process ensures the overall geometry of box girder, and guarantees the effective control of welding deformation and welding quality, achieves a certain economic benefits.%钢结构工程中,箱形钢梁制作工艺复杂,焊接变形控制困难。通过从下料、组装、焊接、矫正等方面详细介绍了核电站RP龙门架箱形钢结构梁的制作工艺过程,该过程保证了箱形钢梁的整体几何尺寸,同时又保证了焊接质量并有效控制了焊接变形,取得了一定经济效益。

  15. 两跨连续斜交梁桥振动台试验研究%Shaking table tests for a two-span continuous skew girder bridge

    Institute of Scientific and Technical Information of China (English)

    许永吉; 卓卫东; 孙颖

    2016-01-01

    The dynamic characteristics and three-dimensional seismic response of a two-span continuous skew girder bridge were analyzed,using parameters,such as,skew angle,shear span ratio,reinforcement ratio and axial compression ratio and so on.Taking a skewed girder bridge of Fujian as an engineering example,a 1 ∶5 scale two-span continuous skewed girder bridge model was designed for shaking table tests.Adopting shaking table tests and FE numerical analysis, the seismic responses and damage characteristics of the skewed girder bridge were studied.Results of shaking table tests showed that the structure's acceleration response and displacement response are guite different under different types of ground motion and at the same site or different types of ground motion and at different sites;under the same skew angle. the smaller the axial compression ratio,the larger the acceleration and displacement responses;when the axial compression ratio is the same,the smaller the skew angle,the larger the acceleration and displacement responses;a reasonable choice of skew angle has a great influence on the dynamic performance of skew bridges in the design of skew bridges.%选取了斜交角、配箍率和轴压比等设计参数,对两跨连续斜交梁桥进行结构动力特性分析和单向地震动输入下结构的地震反应分析。以福建省高速公路某座斜交梁桥为工程背景,设计制作了一座1/5缩尺两跨连续混凝土斜交梁桥试验模型,结合振动台模型试验和数值模拟分析,研究斜交梁桥地震响应及震害特点。振动台模型试验结果表明:不同场地类别的地震动及同一场地类别但不同的地震动作用下,结构的加速度响应、位移响应差别较大;在相同斜交角时,轴压比越小,加速度和位移响应越大;当轴压比相同时,斜交角越小,加速度和位移响应越大。从试验可知,在斜交桥设计中,合理选择斜交角对桥梁动力性能有很大的影响。

  16. Full scale test of a SSP 34m box girder 2. Data report; Reinforced glass fiber/epoxy used in wind turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Find M.; Branner, K.; Nielsen, Per H. (and others)

    2008-05-15

    This report presents the setup and result from three static full-scale tests of the reinforced glass fiber/epoxy box girder used in a 34m wind turbine blade. One test was without reinforcement one with cap reinforcement and the final test was with rib reinforcement. The cap reinforcement test was part of a proof of concept investigation for a patent. The tests were performed at the Blaest test facility in August 2007. The tests are an important part of a research project established in cooperation between Risoe National Laboratory for sustainable energy--Technical university of Denmark, SSP-Technology A/S and Blaest (Blade test centre A/S) and it has been performed as a part of Find Moelholt Jensen's PhD thesis. This report is the second data report containing the complete test data for the three full-scale tests. This report deals only with the test methods and the obtained results, no conclusions are drawn. These can be found in papers and patent referenced in the data report. Various kinds of measuring equipment have been used during these tests: acoustic emission, force transducers, strain gauges and optical deformation measuring system (DIC). The experimental investigation consisted of the following tests: 1) Flapwise bending with no reinforcement 2) Flapwise bending with wire reinforcements 3) Flapwise bending with rib reinforcements. (au)

  17. 预防连续箱梁施工裂缝的温度监测与有限元分析%Temperature monitoring and finite element analysis of preventing construction cracks in a continuous box girder

    Institute of Scientific and Technical Information of China (English)

    王海源; 章龙; 张乐文; 张峰

    2011-01-01

    The features of uneven distribution temperature stress in recently poured concrete and the effective measures to prevent temperature cracks were studied. The 0# box girder in the Weihe Specially Long Bridge located in the highway from Xi' an to Tongchuan was taken as a research project, which was computed on MIDAS/FEA( multitier distributed applications services/finite element analysis) finite analysis element software. The temperature field of hydration heat of the concrete in the construction period was numerically calculated by the finite element method. The effects of three different mechanical control measures of crack control were analyzed. Combined with the results of temperature detection, the mechanical control measure was optimized. The results showed that the temperature inside the concrete rose to a peak about 52 hours after the concrete was poured, with or without cooling water pipes in the box temperature difference of the maximum temperature about 10℃. When the temperature difference between inside and outside of the concrete at 20℃ was a good time to remove the template. Temperature stress was concentrated in the junction web plate and diaphragm of the box girder, thus setting the cooling water pipes could improve the uneven distribution of temperature stress. Compared with other results, the whole process temperature monitoring and the finite element dynamic analysis by this method was better at optimizing the engineering measures of crack prevention.%研究混凝土浇筑初期内部温度应力不均匀分布特征和预防温度裂缝的有效措施,以西安至铜川高速公路渭河特大桥某0#箱梁为研究对象,以MIDAS/FEA(multitier distributed applications services/finite element analysis)有限元分析软件为计算平台,采用有限单元法对施工期混凝土水化热温度场进行了数值模拟计算,分析了3种不同防裂工程措施的理论效果,并结合温度监测进行了工程

  18. 大跨结构箱形曲梁的平面内整体稳定性能分析%Analysis of In-plane Stability Performance of Large Span Steel Structure Curved Box-girders

    Institute of Scientific and Technical Information of China (English)

    王元清; 刘莉媛; 丁大益; 石永久; 完海鹰

    2012-01-01

    In order to study the in-plane stability performance of the arc axis both ends hinged curved box-girders, numerical method theory was carried out using finite element software ABAQUS. Two-dimensional curved girder models were established to simulate the in-plane stability of curved box-girders. Influences of different central angles, different slenderness ratio, and different initial geometric imperfections on the in-plane stability performances of the curved box-girder were considered. The differences and laws of the numerical solution and classic theoretical solution of the elastic buckling factor were gained. Effects on the stability factor and regularization slenderness ratio of the initial geometric imperfections were given, and the form of axial load-moment curve was calculated as well. The design formulae for calculating the in-plane stability of arc axis curved box-girders can provide theoretical basis and suggestions for the future design.%为研究两端铰接圆弧轴线箱形截面曲梁的平面内整体稳定性能,采用数值方法对其进行了理论研究,采用ABAQUS有限元软件建立了二维的曲梁模型,模拟曲梁的平面内稳定问题.研究了不同圆心角、不同长细比,以及不同大小的初始几何缺陷对圆弧轴线箱形截面曲梁平面内稳定性能的影响,得到了弹性屈曲系数的数值解与经典理论解的差异和规律,给出了初始几何缺陷对稳定系数和正则化长细比关系曲线的影响,并且计算得到了该形式曲梁的轴力-弯矩关系曲线.提出的圆弧轴线箱形截面曲梁平面内稳定的设计公式可为今后的设计提供理论依据和建议.

  19. 大跨径梁桥长期挠度的控制技术研究%Control Technology of Long-term Deflection for Long-span Girder Bridge

    Institute of Scientific and Technical Information of China (English)

    黄新哲

    2011-01-01

    This paper analyzed the development of large-span girder bridge, based on the problems of long-term deflection in large-span girder bridge, put forward the causes of long-term deflection and control measures by an example of a bridge, to provide reference for the relevant project officers.%文章就大跨梁桥发展概况进行了剖析,针对大跨梁桥长期挠度的问题现象,以某大桥为例提出了长期挠度成因及控制措施新途径,以供相关工程人员参考.

  20. 斜拉桥主梁应变监测分析%Girder Strain Analysis of a Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    邵平

    2012-01-01

    The health monitoring system of the bridge maintenance management is an important means to ensure the safety operation. To grasp the working condition, strain analysis is necessary. With practical engineering of a bridge in Xinmi, appling finite-element analysis software of MIDAS/Civil to establish the space model, we analysis the stress of the girder in the construction stage and compare the academic value and the practical value. The conclusion will provide a reference to the same bridges.%基于健康监测系统的桥梁养护管理是保证其安全运营的重要手段.而对监测数据进行分析以把握结构的工作状态是一个必须环节.结合新密某桥梁的工程实践,运用有限元软件建立主梁有限元空间模型,模拟分析施工阶段主梁应力,并对应力理论值和实测值进行对比与分析.结论将为同类桥梁应力监测提供参考.

  1. 斜拉桥主梁大型 0 号块施工技术%Construction Techniques for Massive No .0 Main Girder Block of Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    付浩; 严杰; 尹振君; 潘立泉

    2015-01-01

    武汉西四环汉江特大桥主桥为(77+100+360+100+77 ) m预应力混凝土梁斜拉桥 ,主梁为π形结构 ,两边为单箱双室、中间为纵横梁加桥面板结构形式.主梁0号块宽44 m、长22 m ,采用钢管桩贝雷梁支架现浇施工.支架由底模系统、横梁(贝雷梁)、桩顶分配梁、砂筒、钢管支架组成 ,支架施工完后采用反力架预压钢管桩 ,边箱室顶板底模采用透水模板布施工.通过混凝土配合比优化 ,配制高耐久性、稳定性的C55高性能混凝土 ,并采用天泵和地泵从两个方向分层浇筑 ,桥面纵、横坡采用提浆整平机控制.在0号块混凝土强度成长期预张拉横向预应力 ,纵向预应力待1号和1′号块施工完采用连接器连接构成整束一次性张拉 ;预应力采用智能张拉系统张拉、智能压浆系统压浆.实践表明 ,该桥采用该施工技术成功克服了支架不均匀沉降 ,有效控制了裂纹的产生 ,保证了主梁0号块的施工质量与施工安全.%The main bridge of the Hanjiang River Bridge on the west Fourth Ring Road in Wu-han is a prestressed concrete girder cable-stayed bridge with span arrangement of (77+100+360+100+77) m.The two edge boxes (two-cell single box structure) together with the central lattice beam covered with deck slabs form theπ-shaped main girder.The No.0 block of the main girder , cast on scaffolds made up of steel pipe piles and bailey trusses ,is 44 m wide and 22 m long.The scaffolds are composed of the chassis ,floor beam (bailey truss) ,pile-top distributive beam ,sand bailer and steel pipe supports.After the completion of the construction of the scaffolds ,the steel pipe piles were pre-compressed using reaction frame ,and the chassis for the top plate of edge boxes are constructed by using permeable formwork cloth.During the concreting ,the concrete mixing proportion was optimized ,the C55 high-performance concrete with sound durability and stability was prepared ,and the layered

  2. Bar Simulation Method for Analysis on Long-term Behavior of Reinforced Concrete Box Girder%配筋混凝土箱梁长期受力性能的比拟杆分析

    Institute of Scientific and Technical Information of China (English)

    方志; 伍琼芳; 曹国辉

    2012-01-01

    为使配筋混凝土箱梁长期受力性能的分析趋于简便,将线弹性匀质箱梁短期弯曲性能分析的比拟杆法推广应用于其长期受力性能的分析.引入按龄期调整的有效弹性模量来考虑箱梁混凝土徐变的影响,基于换算截面的原理来考虑箱梁配筋的影响,建立能综合考虑箱梁受力特征和配筋影响的混凝土箱梁长期受力性能分析的比拟杆法.对一根预应力混凝土模型箱梁进行长达l001d的徐变试验,并用其结果对所提方法的适用性进行验证.结果表明:混凝土箱梁长期受力性能的比拟杆法计算结果与试验结果之间吻合较好.与试验值相比,t0~1001d时段内箱梁顶板混凝土压应变的计算值相差7%~11%、跨中截面长期挠曲变形的计算结果相差9%~17%.随着持荷时间的增长,箱梁顶板的剪力滞系数逐渐减小,持荷1001d后剪力滞系数减小了7.1%.%In order to develop a simple method to determine the long-term behavior of the reinforced concrete box girder structure with the shear lag effect of box girder involved, a new bar simulation method was presented in which the Age-adjusted Effective Modulus was used to consider the effects of concrete creep and the principle of transformed section was used to consider the effects of reinforcement. The results of the method were testified by the long-term performance test of a prestressed concrete simply-supported box girder under sustained loading of 1001d. The results show as follows:The developed method can give a reasonable prediction to the creep reponse of the concrete box girder; compared with the measured values, the predicted compressive strain in the top plate and the long-term deflection at the mid-span of the tested box girder is of error range of (7~11)% and (9~17)% respectively;the shear lag coefficient of the top plate of the box girder reduces gradually in extension of the sustained loading period and till by 7. 1% after 1001d.

  3. 大跨度连续下承式钢箱拱桥设计%Design of Long-Span Continuous Through Type Steel Box Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    李国普; 李斐然

    2016-01-01

    为满足桥梁的景观和功能要求,小浪底坝后保护区交通桥上部结构采用(95+152+95) m三跨连续下承式钢箱拱结构。主梁为预应力混凝土π形梁,采用钢管桩+贝雷梁法施工。拱肋为钢箱提篮拱,结构用钢采用Q345D钢板,先工厂预制再现场焊接成型。吊索采用7根φ15.2环氧喷涂无粘结钢绞线,缠包后热挤HDPE ,抗拉强度标准值1860 M Pa。下部结构采用柱式台、倒V形实体薄壁墩、高桩承台、钻孔灌注桩基础。采用非线性程序TDV进行计算分析,结果表明,该桥的强度、刚度和稳定性以及抗震性能均满足规范要求。%To meet the landscape and function requirements proposed , the transportation bridge in the conservation area behind the Xiaolangdi Dam adopts a three‐span continuous through type steel box arch bridge structure with span arrangement of (95+152+95) m .The main girder is the prestressed concrete π‐shaped girder ,constructed by the combined use of steel tube piles and bailey truss .T he arch ribs are the steel box basket handle arches .T he predominant material used for the structure is the Q345D steel plate ,and all the components are prefabricated in the factory and transported to the bridge site for welding to take shape .Each hanger consists of 7φ15 .2 epoxy non‐binding steel strands ,extruded with HDPE after wrapping .The hanger has a standard tensile strength of 1 860 MPa .The substructure of the bridge incorporates column‐type abutments ,in‐versed V‐shaped solid thin‐wall piers ,high‐rise pile caps and bored piles .The non‐linear program TDV was used to do calculation .The results of the calculation demonstrate that the strength ,ri‐gidity ,reliability and anti‐seismic performance of the bridge all meet the code requirements .

  4. Study of Lining Concrete Arrangement for Multi-Cell Single Box Composite Girder with Corrugated Steel Webs%单箱多室波形钢腹板组合箱梁内衬混凝土布置方式研究

    Institute of Scientific and Technical Information of China (English)

    邓文琴; 张建东; 刘朵; 胡隽

    2016-01-01

    为优化波形钢腹板内衬混凝土组合结构受力,以南昌朝阳大桥通航孔桥———单箱多室波形钢腹板单索面多塔斜拉桥为工程背景,通过理论计算和有限元分析研究了单箱多室波形钢腹板组合箱梁内衬混凝土布置形式对结构抗剪性能的影响。结果表明:有无设置内衬混凝土对单箱多室波形钢腹板组合箱梁腹板剪应力水平较高的波形钢腹板影响较大,对腹板剪应力水平较低的波形钢腹板影响较小;内衬混凝土单侧设置和双侧设置波形钢腹板剪应力的影响相差不大;内衬混凝土双侧设置及仅有内衬混凝土无波形钢腹板设置对混凝土剪应力的影响相差较小;对单箱多室波形钢腹板组合箱梁高剪应力水平腹板内衬混凝土可以考虑双侧布置或仅设置混凝土腹板,不设置波形钢腹板;而剪应力水平较低的腹板则考虑设置单侧内衬混凝土。%To optimize the load bearing capacity of the corrugated steel web and lining concrete composite structure ,the navigational channel bridge of Nanchang Chaoyang Bridge was taken as the study background .The bridge is a multi‐pylon multi‐cell single box girder cable‐stayed bridge with corrugated steel webs and the stay cables are fanned out in single cable plane .The influence of the arrangement of lining concrete in the multi‐cell single box composite girder with corrugated steel webs on the anti‐shearing performance of the structure was studied via theoretical calculation and finite element analysis .The results indicate that the addition of lining concrete has significant influence on the corrugated steel webs with higher shearing stress in the multi‐cell single box gird‐er with corrugated steel webs ,but slight influence on the corrugated steel webs with lower stress level .No matter the lining concrete is added to a single side of the webs or to both the two sides of the webs ,the influence exerted

  5. Study about Ultimate Bearing Capacity of Large Steel Box Girder under the Action of Shear Force%剪力作用下大型钢箱梁极限承载力研究

    Institute of Scientific and Technical Information of China (English)

    王龙奉; 吕彭民; 徐田

    2015-01-01

    The rules about the ultimate bearing capacity of the welded box girder in the current GB5001 7-2003 “Structural Design Specification”are faulty.The influences of the material non-linearity, geometrical non-linearity and the initial defect are considered in this paper.The arc length increment method obtained by revising Newton-Raphson formula is used to solve the ultimate bearing capacity of welded box girder under the action of the shear force,and the correctness of the calculation method is validated through the model tests.The formula used to calculate the stable ultimate bearing capacity under the action of the shear force of the box girder is summarized through large of simulation calculations.The method relates di-rectly the ultimate bearing capacity to the height to thickness ratio of the web and width to thickness ratio of the wing plate,which has the reference value to calculate and design the stable ultimate bearing capacity of the welded box girder.%现行 GB50017-2003《钢结构设计规范》对焊接箱形截面梁极限承载力规定还比较粗糙,本文考虑材料非线性、几何非线性和箱梁初始缺陷的影响,采用对 Nweton-Raphson 公式进行修正的弧长增量法求解剪力作用下焊接箱梁极限承载力,并通过模型试验,验证了计算方法的正确性。通过大量的数值模拟仿真计算,归纳总结出了箱形截面梁在剪力作用下稳定极限承载力计算公式。该公式把极限承载力与腹板高厚比、翼板宽厚比直接关联起来,对焊接箱形截面梁稳定极限承载力的计算及设计具有参考价值。

  6. Research on High Speed Maglev Transrapid Girder-on-Bridge System%高速磁浮桥上梁轨道系统方案研究

    Institute of Scientific and Technical Information of China (English)

    成广伟

    2012-01-01

    针对高速磁浮交通新项目前期选线中主要采用的高架线路方案开展了相关工程化应用研究,并介绍了针对高速磁浮高架线路轨道系统方案的优化研究进展.研究立足于优化磁浮系统布置、提高安全疏散效率、节约用地、提高环境保护水平等原则,明确了桥上梁轨道系统方案及相关系统设备布置,提出了结合桥上梁形式的安全疏散逃生方案.通过动模型试验与有限元仿真分析方法,研究了磁浮列车通过桥上梁结构时的空气动力学性能,表明磁浮列车的高速通过空气动力学性能符合要求;结合上海磁浮示范线进行了桥上梁方案的在线模拟展示和降噪性能测试,结果表明,结合声屏障,可将磁浮列车高速气动噪声降低最高13 dB(A).研究结论在相关工程方案中得到了应用,可为类似高速交通系统工程提供参考.%The construction application study on the elevated structure proposed in the new high speed rnaglev transportation line and the advances on the high speed maglev transrapid girder-on-bridge system are introduced in this paper. New practical elevated guideway system is designed based on the principles of optimization of the maglev system arrangement, high escape efficiency, economic use of land and better environment protection, etc. One new guideway system type is provided together with the system arrangement, and one new escape system is provided which can be used in the girder on bridge maglev system. With model test and simulation analysis, the aerodynamic effect of this structure when maglev trains passing was examined, and the test results show that the aerodynamic effect when maglev vehicle passing by is acceptable. This girder on bridge system was presented on the Shanghai maglev demonstration line, and the noise reduction effect was tested. Test results show that noise can be reduced to 13 dB( A) with the barrier screen fixed. Conclusions introduced in this paper

  7. Performance of streamlined bridge decks in relation to the aerodynamics of a flat plate

    DEFF Research Database (Denmark)

    Larose, Guy; Livesey, Flora M.

    1997-01-01

    The aerodynamics of three modern bridge decks are compared to the aerodynamics of a 16:1 flat plate. The comparisons are made on the basis of the analytical evaluation of the performance of each cross-section to the buffeting action of the wind. In general, the closed-box girders studied in this ...... in this paper showed buffeting responses similar to a flat plate with the exception of the multi-box girder which performed much better aerodynamically.......The aerodynamics of three modern bridge decks are compared to the aerodynamics of a 16:1 flat plate. The comparisons are made on the basis of the analytical evaluation of the performance of each cross-section to the buffeting action of the wind. In general, the closed-box girders studied...

  8. U-girder coupling vibration and comfort evaluation of new vehicle-bridge%新型U型梁车桥耦合及舒适性评定

    Institute of Scientific and Technical Information of China (English)

    王彬力; 白光亮

    2011-01-01

    This study aim at exploring the impact on the passenger comfort of dynamic response of U - girder in vehicle - bridge system for urban rail transit. In order to study the impact, a rail vehicle dynamics model with 31 DOFs (degrees of freedom) was established by employing linear rail model. A standard span of 30 m single line U - shaped structure, which is in the elevated section of Chongqing City Metro line Project in the west of Liang hill, was taken as the study object. The analysis of coupling vibration in vehicle - bridge system was calculated by using a self - compiled program and compared with the field test results to show the correctness of the established dynamic model and the self - compiled program. According to ISO2631. UIC513 and GB5595 -85 evaluation standard, the train ride comfort was evaluated. The results show the train ride comfort is good.%为探讨城市轨道交通U型梁车桥系统车桥耦合振动对旅客舒适性的影响,采用线性化轮轨模型建立了31个自由度的车辆动力学模型.以重庆市轨道交通一号线工程中梁山以西高架区间所采用标准跨径为30m的单线小U结构为对象,采用自编程序和通用对机车车辆过桥时的车桥耦合振动进行了分析,参照IS02631.UIC513和GB5595-85评价标准,对列车乘坐舒适性进行了评定,结果表明,列车具有良好的乘坐舒适性.

  9. 铜陵公铁两用长江大桥桁片式钢桁梁立体试拼装工艺%Techniques for Trial Vertical Assembly of Steel Truss Girder of Tongling Changjiang River Rail-cum-Road Bridge

    Institute of Scientific and Technical Information of China (English)

    邵天吉; 余本俊

    2014-01-01

    铜陵公铁两用长江大桥为五跨连续钢桁梁三索面斜拉桥,钢桁梁采用板桁结合形式,由3片主桁、上层正交异性公路板式桥面、下层正交异性铁路钢箱桥面及横联构成。钢桁梁采用整体焊接式桁片结构,每2个节间的主桁上、下弦杆,斜杆,竖杆通过整体节点焊接成桁片上桥安装。为验证制造工艺和精度并指导实桥施工,选取3.5个连续节间钢桁梁在工厂内一次完成立体试拼装。由于主桁桁片采用水平拼装制作工艺,采用800 t龙门吊机2×200 t吊钩提升加横移对桁片进行90°转体翻身后试拼装。试拼装过程中设置了抗推拉刚性斜撑增强桁片与铁路桥面的稳定性;在斜杆件加垫片,通过调整间隙控制桥梁预拱度。试拼装过程中设置了测量控制网,检测结果满足设计和验收标准,达到了立体试拼装目的。%The Tongling Changjiang River Rail‐cum‐Road Bridge is a five‐span continuous steel truss girder cable‐stayed bridge with three cable planes .The steel truss girder is the combined or‐thotropic steel plates and steel trusses structure ,containing three main trusses ,the upper ortho‐tropic steel plate deck for vehicles ,the lower orthotropic railway steel box deck and lateral brac‐ings .The steel truss girder is a integrally‐welded truss structure ,the upper and lower chords ,di‐agonal struts and vertical struts of the main trusses in every two blocks are welded by integral nodes to be truss block for assembling on the bridge .In order to verify the manufacturing tech‐nique and precision and to direct the construction of the real bridge ,the steel truss girder in 3 .5 continuous blocks were selected to conduct one‐time trial vertical assembly in the factory .The main truss blocks were fabricated by the horizontal assembling technique ,the 800 t overhead lift‐ing gantry with two lifting hooks of 200 t was adopted to lift and horizontally

  10. Damage detection based on mode shapes of a girder bridge constructed from responses of a moving vehicle under impact excitation

    Science.gov (United States)

    Qi, Zhongqiang; Au, Francis T. K.

    2016-04-01

    The vibration mode shapes are often used to identify damage of bridges because the mode shapes are not only important modal properties but also sensitive to damage. However, the key issue is how to conveniently obtain the mode shapes of a bridge in service. Traditional methods invariably require installation of instruments on the bridge for collection of dynamic responses for constructing mode shapes, which are both costly and inconvenient. Therefore a method is developed to construct the mode shapes of simply supported bridges based on Hilbert Transform using only vehicle acceleration response for identification of the location of damage. Firstly, an algorithm is devised to construct the mode shapes by using the dynamic responses extracted from a moving vehicle under impact excitation. Then, based on these intermediate results, the coordinate modal assurance criterion in conjunction with suitable wavelets is used to identify the location of damage. Compared with the traditional methods, the proposed method uses only the information from the moving vehicle. Moreover, additional impact excitation on the vehicle helps to excite the bridge. This helps to improve the accuracy by overcoming the adverse effects of measurement noise and road surface roughness, which leads to high accuracy of damage detection. To verify the feasibility of the proposed method, some numerical studies have been carried out to investigate the effects of measurement noise, road surface roughness and multiple locations of damage on the accuracy of results.

  11. Seismic vulnerability assessment of a steel-girder highway bridge equipped with different SMA wire-based smart elastomeric isolators

    Science.gov (United States)

    Hedayati Dezfuli, Farshad; Shahria Alam, M.

    2016-07-01

    Shape memory alloy wire-based rubber bearings (SMA-RBs) possess enhanced energy dissipation capacity and self-centering property compared to conventional RBs. The performance of different types of SMA-RBs with different wire configurations has been studied in detail. However, their reliability in isolating structures has not been thoroughly investigated. The objective of this study is to analytically explore the effect of SMA-RBs on the seismic fragility of a highway bridge. Steel-reinforced elastomeric isolators are equipped with SMA wires and used to isolate the bridge. Results revealed that SMA wires with a superelastic behavior and re-centering capability can increase the reliability of the bearing and the bridge structure. It was observed that at the collapse level of damage, the bridge isolated by SMA-HDRB has the lowest fragility. Findings also showed that equipping NRB with SMA wires decreases the possibility of damage in the bridge while, replacing HDRB with SMA-HDRB; or LRB with SMA-LRB increases the failure probability of the system at slight, moderate, and extensive limit states.

  12. 港珠澳大桥非通航孔85 m连续组合梁桥施工关键技术%Key Construction Techniques for 85 m Non-navigational Channel Con-tinuous Composite Girder Bridge of Hongkong-Zhuhai-Macao Bridge

    Institute of Scientific and Technical Information of China (English)

    潘军

    2016-01-01

    港珠澳大桥浅水区非通航孔桥为11联双幅85 m连续组合梁桥,基础采用钢管复合桩,承台及墩身采用预制拼装结构,承台深埋于海床内,上部结构采用组合梁结构。桥位处地质复杂、环境恶劣,利用“小天鹅”号运架双体船搭载整体导向架系统,实现复合桩基础钢管三次定位,精确控制钢管插打;承台+底节墩身整体预制时钢筋按4个模块分别绑扎,组拼成整体后应用自动化开合模板浇筑混凝土,并采用裂纹控制技术及防腐措施;承台+底节墩身预制构件采用“小天鹅”号运架一体船运输、起吊下放进入锁口钢套箱围堰内,通过复合桩桩顶三向调节装置精确定位安装;组合梁的钢梁在工厂加工成板单元后,船运至中山预制场进行整孔组拼,混凝土桥面板采取纵向分块、横向整幅预制,二者结合成组合梁后由“天一号”运架一体船逐片吊装。%The non‐navigational channel bridge in the shallow water area of Hongkong‐Zhuhai‐Macao Bridge is a continuous composite girder bridge with separated left and right decks .The bridge has 11 continuous units of spans of 85 m .T he foundation of the piers is formed of concrete‐filled steel tubular piles ,the pile caps and pile shafts were prefabricated and assembled in the workshop ,and the pile caps were deeply buried in the seabed .The superstructure adopts compos‐ite girder structure .Complicated geological condition and harsh environment render the bridge site quite challenging for construction .The Crane Little Swan ,a catamaran used to lift and erect gird‐ers ,was employed to carry the overall guiding frame system ,to realize three times of positioning of the composite foundation steel tubes and precisely control the driving of the steel tubes .The pile cap and the bottom lift of the pier are monolithically prefabricated ,during the manufacture of which ,the reinforcement was divided

  13. Development of a new-type super-long bridge; Chochotaikyo ni tekigoshita shinkeishiki kyoryo no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, K.; Shimodoio, H.; Saito, T.; Nogami, C.; Oryu, T.; Morikawa, M. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1998-12-20

    In order to realize large strait-crossing projects in the near future, it is necessary to develop a new type of super-long span bridge, which has a superior aerodynamic stability and is cost effective. We have been proposed a new type of suspension bridge using a 2-box and 1-box combined girder to apply to such a project And this time, we propose the cable stayed suspension bridge using a 2- box and 1-box combined girder aiming for improvement of aerodynamic stability with increase of torsional rigidity. This paper describes the performance of this cable stayed suspension bridge obtained from aerodynamic analysis. As a result, it can be confirmed that this newly developed cable stayed suspension system has fine characteristics and shows more potential for economical construction than the early proposed suspension system. (author)

  14. An improved approach for analyzing shear lag effect of box girders%箱形梁剪力滞效应的改进分析方法研究

    Institute of Scientific and Technical Information of China (English)

    张元海; 白昕; 林丽霞

    2012-01-01

    以薄壁箱梁的弯曲理论为基础,从分析翼缘板的面内剪切变形和弯曲剪力流的分布规律入手,从理论上证明二次抛物线是箱形梁剪力滞效应分析中的合理翘曲位移函数。选取剪力滞翘曲位移函数时,对悬臂板和底板引入修正系数,并考虑翘曲正应力的平衡条件。对箱形梁横截面上新出现的广义内力给出明确定义并称之为剪滞力矩,从分析正应力在翘曲虚位移上的虚功出发,揭示所定义的剪滞力矩即为相应于剪力滞广义位移的广义内力。对简支箱梁和连续箱梁模型的应力计算表明,计算值与实测值吻合良好,从而证实该文的分析方法和建立的公式是正确的。挠度计算表明:剪力滞效应使简支箱梁和连续箱梁算例的跨中挠度分别增大12%和19%,工程实践中必须认真对待。%Based on the flexural theory for thin-walled box girders, quadratic parabola is proved to be reasonable as the warping displacement function in shear lag effect analysis of a box girder through investigating the in-plane shear deformation and the shear flow in the flanges. Modified factors for the cantilever and bottom slabs are introduced in the warping displacement function for shear lag and the equilibrium condition for warping stresses is also considered. The new generalized internal force is defined explicitly and named as shear lag moment, which is proved to be the generalized moment corresponding to the generalized displacement for shear lag, through analyzing the virtual work done by the normal stress on the virtual warping displacement. Simply supported and continuous box girder models are analyzed and the calculated results are in good agreement with the test results, which validates the proposed method and formulas. For the simply supported and continuous box girder models, shear lag effect increases the mid-span deflections by 12% and 19%, respectively, which should be treated

  15. Structural health monitoring of bridges in the State of Connecticut

    Institute of Scientific and Technical Information of China (English)

    Chengyin Liu; Joshua Olund; Alan Cardini; Paul D'Attilio; Erie Feldblum; John DeWolf

    2008-01-01

    A joint effort between the Connecticut Department of Transportation and the University of Connecticut has been underway for more than 20 years to utilize various structural monitoring approaches to assess different bridges in Connecticut.This has been done to determine the performance of existing bridges,refine techniques needed to evaluate different bridge components,and develop approaches that can be used to provide a continuous status of a bridge's structural integrity,This paper briefly introduces the background of these studies,with emphasis on recent research and the development of structural health monitoring concepts.This paper presents the results from three different bridge types:a post-tensioned curved concrete box girder bridge,a curved steel box-girder bridge,and a steel multi-girder bridge.The structural health monitoring approaches to be discussed have been successfully tested using field data collected during multi-year monitoring periods,and are based on vibrations,rotations and strains.The goal has been to develop cost-effective strategies to provide critical information needed to manage the State of Connecticut's bridge infrastructure.

  16. 曲线薄壁箱梁侧向静力分析的能量变分法%ENERGY-VARIATIONAL METHOD OF LATERAL STATIC ANALYSIS OF THIN-WALLED CURVED BOX GIRDERS

    Institute of Scientific and Technical Information of China (English)

    甘亚南; 周广春; 吴亚平

    2011-01-01

    以能量变分原理为基础,在曲线箱梁侧向综合考虑了剪力滞后和剪切变形效应的影响,建立了薄壁曲线箱梁的侧向弹性控制微分方程和自然边界条件,获得了相应广义位移的闭合解.论文提出了一种曲线箱梁侧向静力学特性分析的解析法,揭示了各参数之间的内在联系.算例中论文解析解与板壳有限元结果吻合较好,证明了本文方法的有效性,因而更具理论价值和工程实际意义.%Based on the energy variation principle, this paper proposes an approach of analyzing the effect of shear lag,shear deformation on the lateral static characteristic of curved thin-walled box girders generally applied in engineering. The minimum potential principle is applied to establish the lateral governing differential equations and the corresponding natural boundary conditions. The closed-form solutions of generalized displacements are obtained. The variations of shear lag effects of curved box girders,caused by the change of factors such as span-height ratio,types of loading and natural boundary conditions,are discussed. The results are compared with finite shell element solutions to verify the validity of the proposed approach.

  17. 同步控制顶升、摩阻自平衡平移连续箱梁技术研究及其应用%Study and Application on Synchronizing Control Jacking-up and Self-equation of Friction Technology for Translation of Continuous Box Girder

    Institute of Scientific and Technical Information of China (English)

    卢朋

    2015-01-01

    某客运专线一联道岔连续梁因土堆堆载产生横向偏移,在多跨连续梁桥精确复位中,对同步控制顶升、摩阻自平衡平移技术进行研究。连续箱梁对竖向不均匀位移高度敏感,桥墩与梁底之间空间有限,横向反力台座施工困难,通过对比分析、模拟计算,采用 PLC 计算机同步控制顶升、摩阻自平衡平移技术,能保证顶升过程中的同步性,并巧妙平衡了水平千斤顶横向顶推反力。通过工程实例的应用,证明技术的安全性和可行性。%Due to the load of earth piling,the lateral deviation was occured in a continuous beam of turnout with a joint in a passenger dedicated line,the study on synchronizing control jacking-up technology and self-equation of friction technology for translation in accurate restoring of multi-span continuous beam bridge was introduced.Continuous box girder was highly sensi-tive to vertical non-uniform displacement,and the gap between top of pier and bottom of beam was limited,that caused diffi-culty in construction of lateral counterforce pedestal.By the comparative analysis and simulative calculation,the result showed that synchronizing control jacking-up technology and self-equation of friction technology by adopting PLC computer for translation of continuous box girder could not only ensure the synchronism in jacking-up process,but also subtly balance the lateral jacking counterforce of horizontal jack.The safety and feasibility of technology were proven through application of the project.

  18. 高铁板式轨道区段箱梁结构噪声辐射分析%Noise Radiation Analysis of Box-girder Structure in Slab Track Section of High Speed Railways

    Institute of Scientific and Technical Information of China (English)

    石广田; 杨新文; 张小安; 杨建近

    2015-01-01

    A high speed train-track coupling dynamics model was established using Simpack software, and the wheel/rail vertical contact force excited by track irregularity spectrum was calculated. The wheel/rail vertical force was taken as a boundary condition and applied to the finite element model (FEM) of an elevated box girder structure to calculate its surface vibration response. Then, the vibration response was taken as the acoustic boundary conditions and was applied to the bound-ary element model (BEM) of the elevated box-girder structure to analyze its sound radiation. The results show that, using the finite element method and the boundary element method, the vibration noise of the concrete simply-supported box-beam structure can be effectively calculated with shell elements. The vibration noise is mainly concentrated in the low frequency range of 0-200 Hz, and the peaks mainly appear at the central frequencies of 16 Hz, 25 Hz, 80 Hz-100 Hz. The sound pres-sure level decreases with the increase of the distance from the ground in the lateral sound field and this tendency is more ob-vious for lower frequency sound field. The sound pressure level generally increases with the increase of the distance from the ground in the vertical acoustic field, and the sound pressure level in far field area does not change obviously for the fre-quencies below 31.5 Hz. In the range of 80 Hz-100 Hz, the sound pressure levels of the field points near the girder, especial-ly above the girder, are higher than those in the other regions.%利用Simpack软件建立高速列车-轨道耦合动力学模型,计算在轨道不平顺谱激励下的轮轨垂向力,以此作为载荷边界条件施加到高架箱梁结构的有限元模型。计算了高架箱梁表面的振动响应,并利用箱梁结构振动响应作为声学边界条件。进而又采用间接边界元法对其进行声辐射分析。研究结果表明,利用板壳单元,采用有限元—边界元方法能够有效

  19. Seismic vulnerability analysis of regular continuous girder bridges%规则连续梁桥地震易损性研究

    Institute of Scientific and Technical Information of China (English)

    张菊辉; 管仲国

    2014-01-01

    Structural performance indices for regular continuous girder bridges under different damage states were discussed based on the displacement ductility ratio.On the OpenSees platform,a structural dynamic analysis model was established by using nonlinear fiber beam elements.100 earthquake ground motion records were selected,and the nonlinear time-history analysis was performed,thus the fragility curves under different damage states were constructed. Through parametric analysis,the effects of pier height,bearing types and transverse reinforcement ratios on the fragility curves were studied.The results show that the development degree of ductility of the continuous bridge has a great effect on the structural seismic vulnerability.The fragility curves obtained under minor damage and moderate damage seem to be very close;while under extensive damage,the bridge shows a good performance against earthquake forces.With the increase of pier height,the lower level of damage probability of the structure is observed;meanwhile,the improvement in the fragility by using the plate rubber bearings is excellent for a short-pier bridge,but very limited for a high-pier one. The effect of increasing the transverse reinforcement ratio on fragility curves can be neglected for structural damage in early stage,but it can significantly increase the structural capacity from collapse.%基于位移延性比探讨规则连续梁桥在不同损伤状态下的结构性能控制指标;基于OpenSees平台采用纤维模型建立结构动力分析模型,选取100条强震记录通过非线性时程反应分析计算结构地震易损性曲线。研究不同墩高、支座形式及配箍率对结构地震易损性影响,结果表明,连续梁桥的地震易损性受延性发育程度影响较大,发生中等与轻微破坏概率较相近,对严重破坏有较好的耐损性;结构耐损性随墩高的增大而增加;采用板式橡胶支座可显著提高矮墩桥梁的耐损性,对

  20. Numerical simulation for local failure of a steel box girder under blast loading%钢箱梁爆炸冲击局部破坏的数值模拟

    Institute of Scientific and Technical Information of China (English)

    蒋志刚; 朱新明; 严波; 姚术健

    2013-01-01

    The local failure of a steel box girder under blasting loads of vehicle bomb (TNT equivalent 100-500kg)was investigated with the nonlinear finite element software LS-DYNA and the fluid-solid coupling method ALE Multimaterial formulations.The results showed that there are two local failure modes of a steel box girder,one is that the deck and bottom plates rupture locally; the other is that the deck plate ruptures locally and the bottom plate does not rupture but has a local large plastic deformation; the main failure modes of diaphragms are large bending plastic deformation and rupture; the failure parameters increase nonlinearly with increase in explosive TNT equivalent; the impact effect of shock wave within the box on the bottom plate and diaphragms is less than the impact effect of the deck's fragments,the latter is the main cause of the local large plastic deformation and rupture of the bottom plate and diaphragms.%运用LS-DYNA非线性有限元软件,采用ALE多物质流-固耦合算法,研究了汽车炸弹(TNT当量100~500 kg)桥面爆炸冲击作用下钢箱梁的局部破坏.结果表明,钢箱梁局部破坏模式有两种:(1)桥面板和底板均破口;(2)桥面板破口,底板产生局部塑性大变形.隔板的主要破坏模式为弯曲塑性大变形和破口.破坏参数随炸药当量的增加呈非线性增加.箱体内冲击波对底板、隔板的冲击作用相对较小,顶板破片的冲击作用是底板和隔板产生局部塑性大变形和破口的主要原因.

  1. Evaluation Behavior of Qing Shan Concrete Bridge under Static Load Test

    Directory of Open Access Journals (Sweden)

    Haleem K. Hussain

    2011-07-01

    Full Text Available This study describes and evaluates the state of Qing Shang Bridge. The deterioration of bridge can be summarized due to increased internal forces may be a result of higher loading or due to the sever climatic and environmental weathers changes, bridges need reinforcement because damage due to external factors which reduced the cross-sectional resistance to external loads. The assessment of traffic loading on bridges is subject to large levels of uncertainty. While some allowance is provided in design codes for variable traffic conditions, they are conservative to allow for generalization at a safe level. Also this article identify the design demands of Qing Shan bridge which is located in China/ Heilongjiang Province, He gang - Nen Jiang Road 303 provincial highway, Wu Da Lian Chi area, is an important bridge in the urban areas. The investigation program was include the observation and evaluate the damage in T-section concrete beams , box girder bridges section in additional evaluate the whole state of bridges under static load test, the use of Finite Element Analysis was preferred method to study the behavior of concrete. Furthermore the load test program includes the main beams of bridge. The test results show that the bridge in general structural condition is good. T beam girder of the span No. 10 was tested for static load and need to be strengthening. The concrete box girder shows good state of condition, and no seriously damage effects.

  2. 桥式起重机轻量化主梁结构模型试验研究%Structural Model Test of Lightweight Girder of Bridge Crane

    Institute of Scientific and Technical Information of China (English)

    焦洪宇; 周奇才; 李英; 陈庆樟; 许广举

    2015-01-01

    针对桥式起重机主梁的轻量化设计方案对主梁强度、静态刚度的影响问题,基于相似理论和弹性静力学,采用方程分析法推导出原型主梁与相似主梁应力场相似的相似准则.依据主梁结构形式及受力特点,设计切实可行的主梁结构模型试验方案,开展轻量化主梁结构模型试验研究.结果表明,轻量化主梁在跨中截面腹板下半部分的弯曲正应力有一定程度的增加,腹板上半部分的弯曲正应力(绝对值)有小幅度下降;轻量化主梁在跨端截面的切应力增加幅度较大;轻量化主梁的最大挠度有所下降.依据《起重机设计规范》对轻量化主梁进行强度和静态刚度校核.在满足主梁强度、静态刚度要求的前提下,周期性去除腹板上的部分材料实现主梁轻量化设计具有一定的可行性.%In order to research the influence of girder's lightweight plan on strength and static rigidity, similarity criterions between prototype girder and similarity girder are derived from equational analysis based on similarity theory and elastostatics. The scheme of structural model test is designed reasonably and the study of structural model test is carried out. Results show that bending normal stress of upper half of web at midspan of lightweight girder increases to some extent and bending normal stress of bottom half of web decreases within a narrow range. Shear stress at the end-span declines by a great margin. The maximum deflection of lightweight girder comes down. The strength and static rigidity of lightweight girder are checked based on design rules for cranes. It is feasible to wipe off some material periodically in order to realize the lightweight design of girder on the premise of satisfying the strength and static rigidity.

  3. Research on the Anticorrosion Coating Under the Paved Layer for Highway Steel Box Bridge Deck

    Institute of Scientific and Technical Information of China (English)

    SHEN Cheng-jin; MING Tu-zhang; HU Guang-wei; OU Xue-mei; GEN Ou

    2006-01-01

    The corrosion of the anticorrosion coating and the defects of the asphalt concrete paved layer have been investigated on long-span steel box bridge decks. The anticorrosion coating lies in the middle of two entirely different materials: a highway steel box bridge deck and a paved layer, which is used as anticorrosion and waterproof coating for the steel bridge deck. For our study, electrochemical corrosion and pull strength experiments have been selected for the investigation of the corrosion properties of inorganic zinc rich coating, epoxy zinc rich coating and arc sprayed zinc coating. The adhesive strength between the coatings and the panel, and the effect of the coating corrosion on the shear properties of the paved layers including cast asphalt, thermal asphalt mortar, epoxy asphalt and modified asphalt concrete have been investigated. The results show that the adhesive strength between the coatings and the bridge panel is controlled by the method of pre-processing rust removal. Coating by sandblasting has stronger adhesive strength than coating by shot peening. The results also reveal that shear strength of the paved layer is affected by the corrosion product of zinc coating. The arc sprayed zinc coating has stronger shear strength than zinc rich coatings.

  4. Behaviors of super-long span prestressed cable-stayed bridge with CFRP cables and UHPC girder%CFRP拉索预应力超高性能混凝土斜拉桥力学性能分析

    Institute of Scientific and Technical Information of China (English)

    方志; 任亮; 凡凤红

    2012-01-01

    To discuss the applicability of carbon fiber reinforced polymer (CFRP) cables and reactive powder concrete ( RPC) in super-long span cable-stayed bridges, taking a 1 008 m cable-stayed bridge using steel girder and steel cables as example, a cable-stayed bridge with the same span using RPC (reactive powder concrete) as the girder and advanced composite material CFRP (carbon fiber reinforced polymer) as the cable was designed, in which the cable cross section was determined by the principles of equivalent cable strength and the beam cross section was determined considering the stiffness, shear capacity and local stability. Based on the method of finite element analysis, the comparative study of these two structures on their static properties, dynamic properties, stability and wind resistance were carried out. The results show that it is feasible for using RPC as the girder and CFRP as the cable so as to form a highly efficient, durable cable-stayed bridge of concrete structure and make its applicable span reach about 1 000 m long.%为了探讨碳纤维复合材料(carbon fiber reinforced polymer,CFRP)和超高性能活性粉末混凝土(reactive powder concrete,RPC)在超大跨度斜拉桥中应用的可行性,以主跨1008m的大跨度钢主梁斜拉桥设计方案为例,采用拉索的等强度原则将原桥钢索替换成CFRP索,考虑截面刚度、截面应力和局部稳定等要求,将原桥钢主梁替换成RPC主梁,拟订了一座等跨度的CFRP拉索、RPC主梁斜拉桥方案.采用有限元法分别对两种方案结构的静力特性、动力特性、稳定性能以及抗风性能等进行了分析与比较.结果表明:从结构受力性能角度而言,采用超高性能混凝土主梁和CFRP拉索构成千米级跨度混凝土斜拉桥的结构体系是可行的.

  5. Experiments with Externally Prestressed Continuous Composite Girders

    Directory of Open Access Journals (Sweden)

    M. Safan

    2001-01-01

    Full Text Available Steel-concrete composite girders have attractive potentials when applied in bridge construction. The serviceability performance of continuous composite girders is becoming more and more a deterministic parameter in the design of this type of structures. An effective method for improving this performance is to apply prestressing to control or completely eliminate concrete deck cracking caused by static and time dependent actions. Little literature has been found addressing the experimental analysis of continuous girders prestressed by means of external deviated tendons. The current research aims to investigate the behavior of a double-span steel composite beam externally prestressed by means of continuous tendons in terms of cracking characteristics, load deflection response, and load carrying capacity. The efficiency of prestressing is evaluated by comparing the results to those of a non-prestressed beam with similar cross sections and spans.

  6. 高速列车运行对铁路简支箱梁空气动力特性的影响%Inf luence of high speed train running on aerodynamic characteristics of railway simple-supported box-girder

    Institute of Scientific and Technical Information of China (English)

    肖军; 李小珍; 刘德军

    2015-01-01

    列车—桥梁系统的空气动力特性不仅受组合断面上的气动绕流影响,而且在顺桥向列车对桥梁的影响还呈现出非均匀性及动态变化。以高速列车通过铁路双线32 m 简支梁桥为例,分析头车前35 m至尾车后35 m范围内的桥梁三分力系数变化规律,得到了高速列车运行对该型桥梁不同位置断面空气动力特性的影响规律。研究发现,在任意时刻列车对铁路桥梁的空气动力特性影响都可划分为覆盖区、过渡区和无影响区3个区段,且随着列车在桥上的运行,列车对桥梁的影响区域在动态变化。提出了一种移动窗口模型方法来动态更新桥梁不同部位的气动力系数。该方法真正实现了列车—桥梁系统的动态气动耦合,能够更为精确地模拟风—车—桥系统耦合分析中的动态风荷载。%T he aerodynamic characteristics of train-bridge system are affected by the aerodynamic flow on a hybrid cross section and the effect of vehicle on bridge presents a non-homogeneous and dynamic variation along the bridge direction. T aking the high speed train passing through railway double line 32 m simple-supported box-girder bridge as an example,the variation law of bridge three-component aerodynamic coefficients from 35 m ahead first vehicle to 35 m behind the last vehicle was analyzed and the influence law of high speed train movement on aerodynamic characteristics of different bridge cross section was obtained. T he results indicated that effect of train on aerodynamic characteristics of railw ay bridge could be divided into 3 sections including the coverage area,the transition zone and the non-influence area at any time and the influence area changes dynamically with the train passing through the bridge. T his paper presented a moving window model to dynamically update the aerodynamic coefficients of different bridge parts and has realized the dynamic aerodynamic coupling of vehicle-bridge

  7. 混凝土曲线梁桥双向规则性判别参数影响分析探讨%Bidirectional Regularity Discriminant Parameter Impact Analysis for Concrete Curve Girder Bridge

    Institute of Scientific and Technical Information of China (English)

    王忠欲; 程鹏; 罗德专

    2013-01-01

    为给我国桥梁抗震设计规范的修订提供参考资料,从抗震设计反应谱理论角度,通过改变地震动的输入方向,引入抗侧力桥墩的“相对墩底剪力比”参数来判别混凝土曲线梁桥的双向规则性,探讨了圆心角、曲线半径、跨径、跨宽比和跨高比等结构参数变化对混凝土曲线梁桥横桥向和纵桥向规则性地震行为的影响规律.研究表明:圆心角是影响混凝土曲线梁桥双向规则性的主要因素,而跨径、跨宽比和跨高比等参数的影响可以忽略,曲线半径不应作为定义规则曲线梁桥的参数;曲线梁桥当满足单跨圆心角φ小于35°,且多跨一联累计圆心角φ小于55°时具有双向规则性,规则曲线梁桥的地震力可比拟为等参的直线桥进行简化抗震计算,计算结果偏于保守.%Aimed at providing references for Chinese seismic design code revision, from seismic design response spectrum theory of view, by changing input direction of ground motion, "relative pier shear ratio" parameter of resist lateral force piers is introducied to judge concrete curve girder bridge's bidirectional directions regularity.This study conducts structure parameters change affecting the lateral and longitudinal regularity seismic behavior of concrete curve girger bridge, such as central angle, curve radius, span, the span-width ratio and span-height ratio parameter, etc.Research shows: Central angle parameter is the major factor affecting the bidirectional regularity of concrete curve girder bridge, while the influences by span, span-width ratio and span-height ratio parameters can be ignored ; Curve radius should not be used to define regular curve girder bridge as one parameter; As a curve girder bridge meets the central angle φ less than 35 degrees, meanwhile the accumulative total of central angle of multispans Ψ less than 55 degrees, It satisfies bidirectional regularity,so it can be analyzed by simplified antiseismic

  8. 钢主梁拱桥组合桥面系力学性能分析%MECHANICAL BEHAVIOR ANALYSIS OF COMPOSITE DECK FLOOR OF ARCH BRIDGE WITH STEEL GIRDER

    Institute of Scientific and Technical Information of China (English)

    苏庆田; 李杰; 董冰

    2012-01-01

    钢-混凝土组合结构桥面系近几年开始在拱桥结构中使用,拱桥中组合桥面系受力复杂,其力学性能受钢与混凝土是否连接、是否张拉系杆以及混凝土的浇注顺序等影响.该文采用空间有限元模型,开展了钢主梁拱桥组合桥面系的力学性能研究.研究表明:在钢主梁拱桥结构中混凝土桥面板与钢主梁是否结合对桥面系的整体受力影响甚微,只对桥面系局部位置的混凝土桥面板应力分布有所影响;拱桥中是否安装系杆对桥面系的受力影响较大,而且桥面系的受力与系杆张拉力有密切关系;对于组合桥面系的拱桥采用一次浇筑混凝土桥面板施工方法的桥面系受力要明显优于采用分段浇筑混凝土桥面板的方法.%A steel-concrete composite deck has been used in acrh bridges recently. The mechanism of a composite deck is complex, and was affected by the factors of setting connections between concrete decks and steel girder or not, setting tied bars or not, different deck concrete casting sequences etc. In this paper, mechanical behaviors of a composite deck floor of an arch bridge with steel girders are analyzed by a spatial finite element model. The research results show that whether setting connections between concrete decks and a steel girder or not slightly affects the total mechanical behavior of a deck floor but influents the local stress of the deck; whether setting tied bar affects the deck floor mechanical property greatly and the deck floor stress depends on the tension force of tied bars heavily; as to arch bridge with a composite deck floor, the mechanical behavior of deck floors with casting deck concrete by one time is superior to that of deck floors with casting deck concrete by several times.

  9. 悬索桥板桁结合型加劲梁剪力滞计算的简化方法%Simplified Calculation Method for Shear Lag of Plate and Truss Composite Stiffening Girder of Suspension Bridge

    Institute of Scientific and Technical Information of China (English)

    沈锐利; 颜智法; 唐茂林; 朱军颖

    2015-01-01

    T he simplified calculation method for the shear lag of floor system of the plate and truss composite stiffening girder of suspension bridge was researched in the light of the shear lag characteristics of such type of the structure because the work load of modeling for calculating the shear lag ,using the plate and shell finite element method was enormous and the working efficiency was low .In the simplified method ,the truss in the floor system was converted into a continuous thin‐wall girder by the equivalent beam method and the finite element model of the single main girder suspension bridge that could consider the shear deformation influences w as set up .Based on the variational calculus ,the loading influential intervals that considered the structural geometric nonlinearity influences were taken as the span length of an equivalent simply‐supported girder ,the live load ,suspender forces and bearing reaction forces acting on the intervals were taken as the loads and the shear lag under the action of the combination load was solved on the principle of su‐perposition .By way of example of a railway suspension bridge to be built ,the ANSYS was used to set up the plate and shell finite element model for the w hole bridge of the bridge and the calculation of the shear lag of the model w as analyzed and compared to that implemented by the simplified method .The results of the analysis and comparison proved that the simplified method has high cal‐culation accuracy .%针对采用板壳有限元方法计算悬索桥板桁结合型加劲梁桥面系剪力滞的建模工作量巨大、效率低下的情况,根据该类结构剪力滞的特性,研究其简化计算方法。该方法采用换算梁法将板桁结合桥面系桁梁换算为连续薄壁梁;建立能够考虑剪切变形影响的单主梁悬索桥有限元模型;以变分法为基础,将考虑了结构几何非线性影响的加载影响区间作为等效简支梁的跨

  10. Behaviour of parallel girders stabilised with U-frames

    DEFF Research Database (Denmark)

    Virdi, Kuldeep; Azzi, Walid

    2010-01-01

    Lateral torsional buckling is a key factor in the design of steel girders. Stability can be enhanced by cross-bracing, reducing the effective length and thus increasing the ultimate capacity. U-frames are an option often used to brace the girders when designing through type of bridges and where...... overhead bracing is not practical. This paper investigates the effect of the U-frame spacing on the stability of the parallel girders. Eigenvalue buckling analysis was undertaken with four different spacings of the U-frames. Results were extracted from finite element analysis, interpreted and conclusions...

  11. Study on the shock absorbing technique of high speed railway bridges

    Institute of Scientific and Technical Information of China (English)

    Li Chenggen; Gao Ri

    2011-01-01

    Based on the idea of "bearing function separation", a structural member called shock absorber that makes use of its plastic deformation is presented for reducing the seismic response of the bridge. The design criterion for matching material stress, strain and earthquake fortification aim, is also given. The analysis results show that the high speed railway box girder with the absorber in this paper has great reduction effect in seismic response of the bridge piers.

  12. Numerical simulation on continuous collapse of reinforced concrete girder bridge subjected to vessel collision%钢筋混凝土梁桥船舶撞击连续倒塌数值模拟

    Institute of Scientific and Technical Information of China (English)

    姜华; 王君杰; 贺拴海

    2012-01-01

    The material model and failure index of the element in numerical simulation of the collapse of reinforced concrete bridge under vessel collision were introduced, and then the delicate finite element models for bridge superstructure, substructure and support saddle were set up, where the elastoplastic damage cap model was used for concrete and the elastoplaslic kinematic hardening model was used for steel bar. The numerical simulation of the collapse process of bridge structure caused by vessel collision was carried out and the collapse mechanism of continuous girder bridge was revealed.%详细介绍了钢筋混凝土桥梁船撞倒塌模拟涉及的材料模型和单元失效指标等问题,建立某连续梁上部、下部结构、支座和船舶结构精细有限元模型,将弹塑性损伤帽盖模型用于混凝土,弹塑性随动强化模型用于钢筋,对船舶撞击钢筋混凝土连续梁引起的结构连续倒塌过程进行了数值模拟,揭示了连续梁桥结构的船撞倒塌机理.

  13. 重载交通条件下预应力混凝土预制箱梁的设计研究%The Design and Study of Precast Prestressed Concrete Box Girder on the Condition of Heavy Vehicles

    Institute of Scientific and Technical Information of China (English)

    方华; 包绍伦

    2013-01-01

    榆林至佳县高速公路是陕西省重要的能源运输大通道,交通量构成中的大货车、特大货车及拖挂车占相当大的比例.通过实地调研,建立两种车辆荷载模型,并在新的荷载模型下进行计算分析,与公路Ⅰ级荷载对比后,对预应力混凝土预制箱梁进行重新设计研究.%The highway from Yulin to Jiaxian is an important energy transport corridor in Shaanxi,and large trucks,heavy trucks and trailers accounte for a large proportion in the traffic composition.Through site investigation,two kinds of vehicle load model are established,under which calculations and analysis are carried out.After comparison between the new load and Highway-Ⅰ load,precast prestressed concrete box girder is re-designed.

  14. 侵蚀性环境下桥梁CFRP/BFRP加固后的长期性能试验%Experiment for Long-term Performance of Bridge Girders Strengthened with CFRP/BFRP Sheets and Subjected to Erosion Environment

    Institute of Scientific and Technical Information of China (English)

    孙晓燕; 董伟伟; 王海龙; 何世钦

    2013-01-01

    为了研究侵蚀性环境下服役桥梁构件采用纤维材料加固后的长期性能,对11根具有初始锈蚀损伤的钢筋混凝土梁式构件采用碳纤维布(CFRP)和玄武岩纤维布(BFRP)加固后继续退化的承载力及服役性能进行试验.通过对加固后构件进行电化学加速锈蚀和盐液浸润干湿循环模拟不同程度的后续服役性能退化,研究侵蚀性环境对CFRP和BFRP加固构件在不同后续服役期的承载力、刚度等性能影响规律,同时对比了2种加固材料的耐久性能和成本效益.结果表明:侵蚀性环境下加固后的桥梁构件承载能力评估需综合考虑钢筋锈蚀引起的承载力降低和侵蚀性环境对纤维利用效率的降低;CFRP对刚度提高显著,而BFRP加固具有更好的延性;考虑加固后长期服役性能,CFRP加固后具有较好的耐久性,而BFRP具有较高的成本效益.%To investigate the long-term performance of existing bridge girders strengthened with fiber reinforced plastics (FRP) sheets and subjected to erosion environment, the bearing capacity and service performance experiments of 11 reinforced concrete (RC) girders, which were strengthened with carbon fiber reinforced plastics (CFRP) and basalt fiber reinforced polymer (BFRP) sheets after initial corrosion damage, were conducted. Different subsequent performance degradations for strengthened girders were simulated through electrochemical accelerated corrosion together with wet/dry cycles of salt solution. The effect of environmental erosion on capacity, stiffness and other parameters of CFRP/BFRP strengthened girders in different follow-up service time was tested. The durabilities and costs of the two strengthening materials were also investigated. The results show that the capacity evaluation of bridge girders strengthened with FRP sheets should consider the effect of rebar corrosion together with the environmental reduction of FRP strengthening; the CFRP strengthening improves

  15. Application of Welding box girder flange by Using RAPID Welding Technology%RAPID焊接工艺技术在箱型梁翼缘板焊接的应用

    Institute of Scientific and Technical Information of China (English)

    程国志; 于连康

    2016-01-01

    RA PID焊接技术是目前比较先进的一项焊接工艺技术,它是利用数字控制的电弧曲线参数,进一步压缩电弧,使得电弧热量更集中、更具备熔透能力的一种高速焊接技术。由于其高速、高熔深的焊接工艺特性,被用于单面焊接双面成型的钢结构焊接上,可显著提高焊接生产效率。在铝电解多功能机组生产制造的专业厂,其天车主梁的焊接工艺技术一直是采取MAG焊接工艺技术,焊接质量及效率低。应用RAPID焊接工艺技术对箱型梁翼缘板焊接,与M AG焊接工艺技术在焊接质量、效率、经济性等方面进行对比、分析总结,可知,RAPID焊接工艺技术应用在天车主梁翼缘板的焊接中,综合经济效益较MAG焊接工艺有着显著的提高。%RAPID welding technology is an advanced high speed welding technology , the arc curve parame‐ters of w hich is controlled by digital technology , further compressed arc made the arc heat more concen‐trated , and had more penetration ability . Because of its welding technology properties of high speed and high penetration ,it is used for steel structure which is single -sided welding but double -sided molding , significantly improved the efficiency of welding production .In most aluminum electrolysis multifunctional unit manufacturing plants , the crane girder welding technology has been adopt MAG welding technology , welding quality and efficiency is low . After comparing , analyzing and summarizing the welding technology between RAPID and MAG about welding box beam wing flange , found that the RAPID welding technolo‐gy is better than MAG in welding quality , efficiency , economy and so on . RAPID welding technology used in crane girder flange plate welding , the comprehensive economic benefits is significantly improved than that of MAG welding technology .

  16. FRP 加固 RC 连续梁桥抗震性能试验研究%Tests for aseismic performances of a RC continuous girder bridge retrofitted by FRP jacket

    Institute of Scientific and Technical Information of China (English)

    林元铮; 田石柱

    2016-01-01

    Taking a reinforced concrete continuous girder bridge as the study object,retrofitting the plastic region of piers with FRP jacket,the aseismic performances of the bridge structure were studied with hybrid tests.The fixed pier bearing most seismic action was taken as a test element and physically tested in a lab while the other parts of the bridge structure were taken as calculation elements and simulated numerically with OpenSees.After integrating and combining different parts with the hybrid test platform--OpenFresco,the dynamic responses of the overall bridge structure under seismic action were obtained.At last,the test results and Open Sees finite element analysis ones were compared.The results showed that the aseismic performances of the RC continuous girder bridge can be improved effectively after retrofitted with FRP jacket,and the test results agree well with those of finite element analysis.%以某钢筋混凝土连续梁桥作为研究对象,对其桥墩进行了塑性铰区的 FRP 抗震加固,采用混合试验技术研究了该桥梁结构的抗震性能。将连续梁桥结构承担主要地震作用的固定墩作为试验单元,进行真实的物理试验;将桥梁结构其余部分作为计算单元通过有限元软件 OpenSees 进行模拟,通过 OpenFresco 混合试验平台集成协调,完成了该连续梁桥的抗震混合试验。最后将试验结果与 OpenSees 有限元分析结果进行了对比。研究结果表明,FRP 抗震加固能够有效改善桥梁的抗震性能;试验结果与有限元分析结果吻合较好。

  17. 基于两水平设防的连续梁桥抗震性能分析%Seismic Performance Analysis of Continuous Girder Bridge Based on Two-level Design Approach

    Institute of Scientific and Technical Information of China (English)

    邓小伟

    2012-01-01

    According to the new ideas and new methods by guidelines for seismic design of highway bridges (JTG / T B02-01-2008) , with the background of a continuous girder bridge in the area of 7 degree earthquake intensity, an elastic-plastic finite element model is established for dynamic characteristics analysis, seismic response spectrum analysis and nonlinear time history analysis, to reveal the force and deformation under earthquake action of two levels. Furthermore, the seismic performance is evaluated to provide a reference for seismic design of bridges.%根据《公路桥梁抗震设计细则》(JTG/T B02—01—2008)中的抗震设防新理念和新方法,以Ⅶ度区某连续梁桥为工程背景,建立了弹塑性有限元模型,依次进行了动力特性分析、地震反应谱分析和非线性时程分析,揭示了两级地震作用下桥梁的受力及变形情况,并对桥梁的抗震性能进行了评价,可供桥梁抗震设计参考.

  18. 基于土-结构相互作用的隔震连续梁桥的地震响应%Seismic response of isolated continuous girder bridges based on soil-pile-bridges interaction

    Institute of Scientific and Technical Information of China (English)

    陈水生; 马涌泉

    2012-01-01

    Taking the three spans isolated continuous girder bridges for the engineering background, Bouc-Wen restoring force model is adopted to simulate the nonlinear characteristics for LRB, multi-story liner system concentrated quality finite clement analytic model considering SSI is established, and the time-history analysis procedure of the Wilson- θ step-by-step integration method used to solve the increment form nonlinear governing equation of motion considering SSI is programmed. We make a contrastive analysis based on before and after isolated bridges model of considering SSI and rigid foundation hypotheses by combining the procedure with calculation example. The results indicate that the considering SSI has larger value on the seismic response than the rigid foundation, but the seismic response value has no great difference between two models under pulse of type Ⅰ and Ⅱ- The considering SSI has larger value on the seismic response than the rigid foundation under pulse of type Ⅲ, so the SSI can not be neglected in the isolated seismic design of bridges under pulse of type Ⅲ. The LRB isolated rate has insensitive to considering SSI or not, and LRB isolated rate has no great difference between two models under the same type of pulse, but the effect of LRB under pulse of typeⅠ and Ⅱis superior to effect of LRB under pulse of type Ⅲ.%以典型三跨隔震连续梁桥为工程背景,采用Bouc-Wen滞回恢复力模型,模拟LRB( lead rubber bearings)的力-位移非线性特性,建立了考虑土-结构相互作用的多质点系集中质量有限元计算模型,编制了运用Wilson-θ逐步积分法求解增量形式的土结构体系非线性运动方程的时程分析程序,利用程序并结合算例分别对考虑土-结构相互作用与按照墩底固结假设的两种桥梁模型进行了隔震前后的时程对比分析.结果表明:在Ⅰ、Ⅱ类场地土上,考虑土结构相互作用与按照墩底固结假设相比,前者得到的地震响

  19. On construction and inspection of prestressed continuous rigid box girder%预应力连续刚构箱梁桥施工与监控

    Institute of Scientific and Technical Information of China (English)

    辛亚兵

    2016-01-01

    Taking Xushui Bridge as the example,the paper illustrates the construction technique for the upper and lower structures of bridges,in-troduces the main content and methods for the construction control,observes the elevation and main beam stress,and proves by the result that the upper structure can meet the demands for various indexes in the construction process.%以溆水大桥工程为例,阐述了桥梁下部结构与上部结构的施工技术,介绍了施工控制的主要内容与方法,并对标高及主梁应力进行了观测,结果表明,上部结构在施工过程中的各项指标均满足要求。

  20. Active Control of Suspension Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper some recent research on active control of very long suspension bridges, is presented. The presentation is based on research work at Aalborg University, Denmark. The active control system is based on movable flaps attached to the bridge girder. Wind load on bridges with or without...... flaps attached to the girder is briefly presented. A simple active control system is discussed. Results from wind tunnel experiments with a bridge section show that flaps can be used effectively to control bridge girder vibrations. Flutter conditions for suspension bridges with and without flaps...

  1. Experimental Study of Anchor Tensile Plate Cable Anchorage System in Concrete Girder of Actual Bridge%锚拉板式混凝土索梁锚固体系实桥试验研究

    Institute of Scientific and Technical Information of China (English)

    石雪飞; 周军勇; 胡可; 阮欣

    2016-01-01

    为研究索力作用下锚拉板式混凝土索梁锚固体系的受力性能,以五河淮河大桥为工程背景进行实桥试验和有限元分析。选取该桥0号节段混凝土锚拉板进行实桥试验,测试锚拉板在分级索力作用下的应力及变形,采用ANSYS软件建立有限元模型,计算2种连接方式下(考虑混凝土主梁与钢锚拉板的固结与滑移)的应力分布与锚拉板变形。结果表明,钢锚拉板与混凝土主梁在固结或滑移连接方式下,斜拉索锚固区域的应力分布基本相同,但连接区域的应力分布及锚拉板变位差别显著;测试的锚拉板应力和位移与荷载呈现良好线性相关性,最大测点应力296 M Pa ,结构仍处于弹性工作状态;锚拉板应力分布的实测值与有限元计算值吻合,板件应力扩散和传递效果良好;连接区域的实测应力和位移与滑移方式下的有限元分析较吻合,但摩擦系数不主导滑移结果。%To study the mechanical performance of the anchor tensile plate cable anchorage system in concrete girder under the action of the cable tension ,the test and finite element analysis of the steel anchor tensile plate stay cable anchorage system in the concrete main girder of the actu‐al bridge of Wuhe Huaihe River Bridge were carried out .The anchor tensile plate in the segment No .0 of the main girder of the bridge was selected and tested .The stress and displacement of the anchor tensile plate under the different levels of the stay cable tension were measured .The finite element model for the anchor tensile plate was set up ,using the software ANSYS and the stress distribution and the anchor tensile plate displacement under the 2 kinds of the connecting ways (the rigid fixity and sliding connecting of the anchor tensile plate with the concrete main girder ) were calculated .The results show that under the connecting ways of the rigid fixity or sliding connect‐ing of the anchor

  2. Optimization Design on Closure Scheme of (70+108+70)-m Continuous Girder of Yexihe Bridge in Yichang-Wanxian Railway%宜万铁路叶溪河大桥(70+108+70)m连续梁桥合龙方案优化设计

    Institute of Scientific and Technical Information of China (English)

    杨帆

    2012-01-01

    合龙顺序是大跨径连续梁桥成桥状态的主要影响因素.为研究边中跨比大于常规的连续梁取得最优成桥状态时的合龙方案,采用有限元方法建立了连续梁桥的杆系分析模型,以宜万铁路叶溪河大桥为例,对边主跨比0.648的主跨108 m的3跨连续梁的3种合龙方案进行分析,以应力和位移变化幅度最小为原则,确定出该类跨径比的连续梁采用跨中压重的先中跨合龙、后边跨合龙的合龙方案,有助于实现内力平衡和施工控制.%The sequence of final closure of continuous girder bridge with long-span is a main influencing factor on finished-bridge state. To investigate the closure scheme which should accord with the best finished-bridge state of continuous girder under a ratio of side span to main span bigger than the normal, this article takes Yexihe Bridge of Yichang - Wanxian Railway as an example and establishes the rods-system model of continuous girder bridge by finite element method. Further, the article compares and analyzes respectively three closure-sequence schemes of continuous girder with three spans in which the main span is 108m long and the ratio of side span to main span is 0. 648. Finally, following the principle of minimum variation of stresses and displacements, aiming at the continuous girder with this kind of span radio, the article puts forward the optimal closure-sequence scheme, that is; with the weights in span center, medium span's closure first, then the side span's closure. This optimal closure scheme is helpful to both internal-force equilibrium and construction controlling.

  3. 钢箱梁电弧喷铝防腐涂层无损检测图像分析%Image analysis of arc sprayed aluminum anticorrosive coating on steel box girder based on nondestructive test

    Institute of Scientific and Technical Information of China (English)

    刘丽娜; 刘涛

    2015-01-01

    为研究钢箱梁电弧喷铝防腐涂层防腐机理,预测其防腐寿命,加工制作钢板试样,表面电弧喷铝涂层,进行室内加速腐蚀试验。通过平板扫描仪采集对象图像,观测腐蚀发展过程。采用基于二值化图像的图像处理技术提取腐蚀形貌图像特征参数,并结合规范评定涂层腐蚀损伤级别。研究结果表明:基于二值化图像的图像处理技术可以有效区分涂层腐蚀与未腐蚀区域,实现涂层腐蚀面积定量化分析,为防腐涂层腐蚀等级评定提供新的思路,并估算200μm喷铝涂层实际海洋大气环境下的寿命为63.6年。%To study the anticorrosion mechanism of arc-sprayed aluminum anticorrosive coating on steel box girder and to predict the anticorrosive life of the coating,steel plates were manufactured and painted with aluminum on the surfaces to carry out indoor accelerated corrosion test. Corrosion image of the organic protection coating was collected by a flat scanner to observe its corrosion process. The blistering area was extracted through image processing technology to evaluate the corrosion grade. The results demonstrate that the image processing technology based on binary image can distinguish the corrosion areas from the non-corrosion areas so as to realize quantitative analysis for coating corrosion area. With the help of this technology,a new way has been presented for assessing the corrosion grade of anticorrosive coatings and the service life of 200μm aluminum coating has been estimated to be 63.6 years in the actual marine atmospheric environment.

  4. Simulation Study on Train-Induced Vibration Control of a Long-Span Steel Truss Girder Bridge by Tuned Mass Dampers

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2014-01-01

    Full Text Available Train-induced vibration of steel truss bridges is one of the key issues in bridge engineering. This paper talks about the application of tuned mass damper (TMD on the vibration control of a steel truss bridge subjected to dynamic train loads. The Nanjing Yangtze River Bridge (NYRB is taken as the research object and a recorded typical train load is included in this study. With dynamic finite element (FE method, the real-time dynamic responses of NYRB are analyzed based on a simplified train-bridge time-varying system. Thereinto, two cases including single train moving at one side and two trains moving oppositely are specifically investigated. According to the dynamic characteristics and dynamic responses of NYRB, the fourth vertical bending mode is selected as the control target and the parameter sensitivity analysis on vibration control efficiency with TMD is conducted. Using the first-order optimization method, the optimal parameters of TMD are then acquired with the control efficiency of TMD, the static displacement of Midspan, expenditure of TMDs, and manufacture difficulty of the damper considered. Results obtained in this study can provide references for the vibration control of steel truss bridges.

  5. Assistant pullback technique for main span closure of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Chen Ming; Luo Chengbin; Wu Qihe; Zhang Yongtao; You Xinpeng

    2009-01-01

    Sutong Bridge is a cable-stayed steel box girder bridge with a main span of 1 088 m. The erection of upper structure adopts geometry control method and requires no change to the unit's size and the structure's none-stress geometry. Before main span closure, the cantilever of girder reaches 540.8 m, the structure state is noticeably influenced by external circumstances, the main span closure face great difficulty. By abstracting the advantage of the pullback method abroad and the domestic temperature-cutting method, a new assistant pullback method have put forward and bring into practice actually. In this paper, the analysis key point of practice conditions, key parameter of practice, main measures of the method and the performance is introduced.

  6. The maximum bending moment resistance of plate girders

    NARCIS (Netherlands)

    Abspoel, R.

    2014-01-01

    In many steel structures like buildings, industrial halls and bridges, standard hot-rolled sections like IPE, HEA, HEB, HEM, HED and UNP in Europe and similar profiles in other regions of the world are used. The range of hot-rolled sections is limited and therefore fabricated plate girders are used

  7. 带有挑臂的双层钢桁悬索桥颤振性能风洞试验%Wind tunnel test for flutter stability of double-deck truss girder suspension bridge with cantilever beam

    Institute of Scientific and Technical Information of China (English)

    向活跃; 李永乐; 武兵

    2014-01-01

    为了提高加劲梁的颤振性能,针对某三塔两跨公铁两用悬索桥进行了节段模型风洞试验,探讨了多种气动措施对加劲梁颤振临界风速的影响。结果显示,在三种风攻角下,常规气动措施如增加上下桥面板中央稳定板、铁路道板及检修道开槽等措施降低了加劲梁的颤振临界风速,封闭铁路挑臂并给合上桥面板上、下中央稳定板后,加劲梁在三种风攻角下的颤振性能均大幅提高,使颤振临界风速满足要求。相关结论可为类似桥梁断面的颤振优化提供借鉴。%To improve the flutter stability of stiffened girder, the sectional model wind tunnel tests of a long span highway-railway suspension bridge with two main spans and three towers were carried out. A variety of aerodynamic measures on the flutter stability were explored. The results indicate that conventional aerodynamic measures such as the upper and lower central stabilizer, slotting rail road board and railway maintenance road reduce the critical flutter wind speed in three attack angle cases, while the flutter stability is increased significantly after closing the railway cantilever and u-sing the upper and lower central stabilizer in upper deck, which meets the requirement of standard. The conclusions can provide some references for similar bridge cross-section in the optimization of flutter stability.

  8. Studies on Technical Development of Railway Steel-Concrete Composite Cirider Bridges in China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Steel-concrete composite girder bridge boasts the advantages of strong rigidity,low noise and low construction height.Along with the large-scale construction of passengerdedicated lines (PDL) and high-speed lines (HSL),tests and researches on steel-concrete composite girder bridges have been conducted with the main types of which including steel plate girder-concrete composite girder bridge,deck steel truss girder-concrete composite girder bridge,through steel truss girder-concrete composite girder bridge and through type tied arch composite girder bridge.Based on the application and researches on steel-concrete composite technology and in combination with the engineering construction of railway bridges,the construction of HSL and PDL and upgrading of existing lines for speed-up in China,this paper analyzes the main structural forms of through steel truss girder-concrete composite girder bridges with different spans and structure systems,carries out studies on the force acted upon these bridges and the related theory and methods for design and computation,and puts forward the solutions required in relation to the key technologies for further development of railway steel-concrete composite girder bridges.

  9. 基于梁格法的预制箱梁横向刚度模拟研究%Study of Transverse Stiffness Simulaton Based on Beam Grillage Method for Prefabricated Box Girder

    Institute of Scientific and Technical Information of China (English)

    杨圣超; 夏兴佳

    2016-01-01

    To correctly simulate the transverse stiffness of the spatial beam grillage model of the prefabricated box beam ,the right deck of the Weijiacun Zhong Bridge on the Zhunxing Heavy Load Expressway was taken as the study background ,to study the influence of the type of the vir‐tual beams in the spatial beam grillage model of a prestressed box beam on the transverse stiffness . The bridge is a 4 × 20 m prestressed concrete continuous box beam bridge ,to which full loads was applied according to the static test results gained when the bridge was completed and transferred , to test the strain and deflection of the main beam .The MIDAS Civil software was used to establish the spatial beam grillage models of the main beam with three types of virtual beams ,to calculate the main beam bending moment under the design loads and testing loads ,and the strain and deflec‐tion of the main beam under the maximum positive bending moment and the related verification co‐efficients ,and the calculated results were compared with the measured ones .The results demon‐strate that the transverse stiffness of the spatial beam grillage model show s sign of increase as the increase of the length of the rigid zone of the virtual beam and the decrease of the efficient length of the virtual beam .And when the part of the virtual beam from the center of the stringers to the in‐ner edge of the stringer webs was set as the rigid zone ,the transverse stiffness simulated by the spatial beam grillage model is the closest to the transverse stiffness of the actual bridge .%为准确模拟预制箱梁空间梁格模型的横向刚度,以准兴重载高速公路魏家村中桥右幅桥为背景,研究预制箱梁空间梁格模型中虚梁形式对横向刚度的影响。该桥为4×20 m预制混凝土连续箱梁桥,按交工静载试验满载加载,测试主梁的应变和挠度;采用M IDAS Civil软件建立3种虚梁形式的主梁空间梁格模型,计算设计荷载和试验

  10. 地震作用下中等跨径RC连续梁桥系统易损性研究%Study on system vulnerability of medium span reinforced concrete continuous girder bridge under earthquake excitation

    Institute of Scientific and Technical Information of China (English)

    李立峰; 吴文朋; 黄佳梅; 王连华

    2012-01-01

    Medium span multi-span continuous RC bridges,whose main failure modes are reflected in piers,abutments or bearings,are widely used in China.One common continuous girder bridge is taken as the analytical model;uncertainties in the strength of material and the weight of superstructure are considered,then a set of 10 nominally identical but statistically different bridge samples are developed for the bridge using the Latin hypercube sampling technique.100 earthquake records are chosen from PEER according to the site condition of bridge to account for the uncertainty of ground motions,and then combined randomly with 10 bridge samples.Then,a series of nonlinear time-history analyses are conducted to obtain the responses of structure,and four limit states for different components are defined.vunerability curves of piers,abutments and bearings are obtained utilizing the traditional reliability and probability tools,and furthermore the system vulnerability of structure is studied using the joint failure probability method.The results show that the bearings,especially the active bearing of abutment,are more vulnerable than the column piers and the abutments.The failure probability of bridge system,which is calculated using the first-order and the second-order reliability principles,is larger than those of structural members,indicating that it is more reasonable to assess the seismic behavior of bridge basing on the system vulnerability.%中等跨径混凝土连续梁桥是一种广泛应用的桥梁结构形式,地震作用下该类桥梁的破坏主要体现在桥墩、桥台和支座位置。以一典型多跨连续梁桥为例,考虑材料强度和上部结构容重等不确定性因素的影响,运用拉丁超立方抽样方法建立了10个桥梁样本。根据场地类型从PEER强震数据库中选取100条地震波来模拟地震动的不确定性,并与10个桥梁样本随机组合。对结构进行非线性时程分析后得到结构的响应,并分别定义了

  11. Analysis of effective flange width of small radius curved bridge with single box and double chamber%小半径单箱双室曲线桥梁翼缘有效宽度的研究

    Institute of Scientific and Technical Information of China (English)

    方飞; 张杰; 张鲲; 张振; 方诗圣

    2013-01-01

    针对小半径单箱双室曲线梁桥的剪力滞效应以及选取其翼缘有效宽度的问题,文章依托实际工程,采用有限元软件ABAQUS建立某曲线梁桥的空间有限元模型,分析了荷载为重力、汽车荷载等共同作用下结构的变形和内力,研究不同曲率半径下,剪力滞效应及其对小半径曲线梁桥翼缘有效宽度取值的影响。结果表明:对于单箱双室箱形截面,不同半径作用下,中腹板对应的有效宽度都小于两侧宽度;相比直线桥而言,对于不同的曲率半径,内腹板对应的有效宽度大于外侧腹板;随着曲率半径的减小,各个腹板对应的有效宽度的差值也越来越大。故在确定小半径单箱双室曲线梁桥翼缘有效宽度时,可以在现行桥梁设计规范的计算宽度基础上乘以修正系数。%The shear lag effect of small radius curved bridge with single box and double chamber and the selection of the effective width of flange were studied .Based on the practical engineering ,the de-formation and the inner force of the structure under the interaction of load gravity and vehicle load were analyzed by the spatial finite element model of a curved girder bridge using the finite element software ABAQUS .The shear lag effect of small radius curved bridge with single box and double chamber under different radius of curvature and the influence on the flange’s value were studied .The results show that under the influence of different radius ,the corresponding effective width of medium web is less than bilateral web width for the section of single box and double chamber single box ;com-pared with the straight bridge ,the corresponding effective width of medial web is larger than lateral web’s under different radius of curvature ;the differences of the corresponding effective width of each web become larger and larger with the decrease of radius of curvature .In a conclusion ,the calculative width of current

  12. Design of cable-girder anchorage system scheme in self-anchored suspension bridge%自锚式悬索桥缆-梁锚固系统方案设计

    Institute of Scientific and Technical Information of China (English)

    凌云

    2015-01-01

    本文根据已建以及待建自锚式悬索桥工程实例,将自锚式悬索桥工程中主缆在加劲梁梁端的锚固方案进行了总结分析,从施工方面、经济性以及美观性等方面指出了各种锚固方式的优缺点以及适应性。按照锚体材料的不同将现有锚固方式重新进行了分类,综合现有的分类方式提出了一套锚固系统方案设计流程。这种设计流程条理清楚、直观易理解,为今后的自锚式悬索桥主缆锚固系统设计提供指导,快速的形成锚固系统方案,提高设计效率,并获得更好的经济性和美观性。%According to the engineering examples of the self -anchored suspension bridges built and to be built , the cable -girder an-chored projects are summarized and analyzed.From the construction , economy and aesthetics aspects , the advantages adaptability of vari-ous ways of anchoring and are pointed out.According to the different materials of the existing anchorage , the way of anchoring is re -clas-sified and a set of anchor system design process is put forward based on the classification of the existing anchorage systems .This design process is clear , intuitive and easy to understand and can provide guidance for the design of self -anchored suspension bridge main cable anchorage system in the future.Using this design process , anchorage system scheme will be quickly put forward , the design efficiency can be improved and the bridge will be more economic and more beautiful.

  13. 乌苏大桥主桥上部结构设计与计算%Design and Calculation of Superstructure of Main Bridge of Wusu Bridge

    Institute of Scientific and Technical Information of China (English)

    康晋; 肖海珠; 徐伟

    2011-01-01

    The main bridge of the Wusu Bridge is a single pylon and single cable plane cablestayed bridge with span arrangement (140+140) m and with a structural system of rigid fixity of the pylon, pier and girder. A summarized account of the design and calculation of the superstructure of the bridge is presented herewith. The main girder of the bridge is a composite girder with long cantilevers, the central part of the girder is designed as a two-cell and single-box steel girder and the steel cantilever at each side of the girder is the variable depth I-beam and is provided wiht a trough stringer at the far side, which are all topped with 25 cm thick concrete deck slabs connected with the girder via shearing studs. The part of the main girder close to the pylon is designed as a prestressed concrete box girder to facilitate the fixity of the girder with the pylon. The pylon is the single column pylon, 117 m in height. The stay cables, made up of low relaxation galvanized high strength parallel steel wire strands, are of the harp pattern cable plane arranged in the central alignment of the bridge deck. The finite element software MIDAS Civil 2006 and the SCDS programme are employed to calculate and analyze structure of the bridge. The results of the calculation and analysis indicate that the static, stability and dynamic characteristics of the bridge can meet the requirements in the relevant codes.%乌苏大桥主桥为独塔单索面斜拉桥,跨径布置为(140+140) m,采用塔、墩、梁固结体系,综述该桥上部结构设计与计算.主梁为带大挑臂的钢箱结合梁,中间钢箱梁采用单箱双室截面,两侧钢挑臂为变高度工字形梁,挑臂端部设槽形小纵梁;混凝土桥面板厚25 cm,与钢梁通过剪力钉连接;塔根部主梁采用预应力混凝土箱梁,以方便与桥塔固结;桥塔采用独柱式塔,高117 m;斜拉索为竖琴形中央平行索面布置,采用低松弛镀锌高强度平行钢丝束.采用有限元软件MIDAS Civil

  14. Evaluation of Seismic Performance of Long Span Continuous Girder Bridges Based on Seismic Isolation Design%基于减隔震设计的大跨度连续梁桥抗震性能评价

    Institute of Scientific and Technical Information of China (English)

    李贞新; 刘高

    2011-01-01

    Nonlinear time history analysis method is adopted to analyze dynamic characteristics and seismic performance based on long span continuous girder bridges with spans of 89 m, 170 m and 89 m in high intensity region. The good hysteretic, energy-dissipation characteristics and self-restoring ability of double curvature seismic isolation bearings are simulated as well as the friction energy-dissipation characteristics of sliding bearing and damping energy-dissipation characteristics of dampers. Analytical results indicate that seismic performance can basically meet the expected design goal; seismic isolation device of double curvature spherical supports and dampers can adjust dynamic characteristics, reduce seismic response, dissipate earthquake energy and guarantee the safety of the structure.%基于高烈度区的某大跨度连续梁桥(89 m+170 m+89 m),采用非线性时程分析法进行结构动力特性及抗震性能分析.全桥均采用三维梁单元建立空间模型,对于双曲面球形减隔震支座的滞回耗能特性和自恢复功能,活动支座的摩擦耗能以及固定销剪断后的效应进行了模拟,同时模拟了阻尼器的阻尼耗能作用.研究结果表明:采用双曲面球形减隔震支座及桥台处纵向阻尼器后,结构的反应得到了很好的控制,确保了高烈度区结构的抗震安全性.

  15. A multiscale finite element model validation method of composite cable-stayed bridge based on Probability Box theory

    Science.gov (United States)

    Zhong, Rumian; Zong, Zhouhong; Niu, Jie; Liu, Qiqi; Zheng, Peijuan

    2016-05-01

    Modeling and simulation are routinely implemented to predict the behavior of complex structures. These tools powerfully unite theoretical foundations, numerical models and experimental data which include associated uncertainties and errors. A new methodology for multi-scale finite element (FE) model validation is proposed in this paper. The method is based on two-step updating method, a novel approach to obtain coupling parameters in the gluing sub-regions of a multi-scale FE model, and upon Probability Box (P-box) theory that can provide a lower and upper bound for the purpose of quantifying and transmitting the uncertainty of structural parameters. The structural health monitoring data of Guanhe Bridge, a composite cable-stayed bridge with large span, and Monte Carlo simulation were used to verify the proposed method. The results show satisfactory accuracy, as the overlap ratio index of each modal frequency is over 89% without the average absolute value of relative errors, and the CDF of normal distribution has a good coincidence with measured frequencies of Guanhe Bridge. The validated multiscale FE model may be further used in structural damage prognosis and safety prognosis.

  16. Field Application of Automated Power Arc Spraying System on Steel Bridge Deck

    Institute of Scientific and Technical Information of China (English)

    YI Chun-long; SUO Shuang-fu; SUN Zhi; PANG Xu-nan

    2004-01-01

    The effective corrosion protection coating and high productive coating equipment for steel bridge deck has been a challenge for bridge engineers for many years. An automated power arc spraying system was first designed and field applied to coating the deck of Wuhan Junshan Yangtze River Bridge in high efficiency. This steel bridge is a continuous orthotropic deck box girder cable-stayed bridge with 962 m in length and 38.8 m in width, whose width is the No. 1 in China. The whole orthotropic deck with over 35,000 m2surface area was arc-sprayed a protective coating of zinc on site, followed by a sealant and SMA paving material. The side face and bottom of box girders were arc-sprayed with aluminum in factory.Field application indicated that the newly designed automated power arc spraying system with fan nozzle and separate primary & secondary atomizing air had some advantages over the conventional arc spraying system, such as automated operation,big arc spray current, high spraying rate, big breadth of each coat, even and small atomized particles, high density and low porosity of sprayed coating, and high adhesive strength to the substrate.Working procedure of surface preparation and automated arc spraying on bridge deck were introduced, and the quality of sprayed coating is controlled strictly. Field tests proved that the application of this automated power arc spraying system is successful and suitable for coating the steel bridge deck.

  17. Flutter Derivatives Identification and Aerodynamic Performance of an Optimized Multibox Bridge Deck

    Directory of Open Access Journals (Sweden)

    Zhida Wang

    2016-01-01

    Full Text Available The bridge deck sections used for long-span suspension bridges have evolved through the years, from the compact box deck girders geometrical configurations to twin-box and three-box bridge decks sections. The latest generation of split and multiple-box bridge decks proved to have better aerodynamic behavior; thus further optimization methods are sought for such geometrical configurations. A new type of multibox bridge deck, consisting of four aerodynamically shaped deck boxes, two side decks for the traffic lanes and two middle decks for the railway traffic, connected between them by stabilizing beams, was tested in the wind tunnel for identifying the flutter derivatives and to verify the aerodynamic performance of the proposed multibox deck. Aerodynamic static force coefficients were measured for the multibox bridge deck model, scaled 1 : 80, for Reynolds numbers up to 5.1 × 105, under angles of attack between −8° and 8°. Iterative Least Squares (ILS method was employed for identifying the flutter derivatives of the multibox bridge deck model, based on the results obtained from the free vibration tests and based on the frequency analysis the critical flutter wind speed for the corresponding prototype of the multibox bridge was estimated at 188 m/s.

  18. ABAQUS箱型桥梁的GUI二次开发%Secondary Development for GUI of Box Girder Bridge Based on ABAQUS

    Institute of Scientific and Technical Information of China (English)

    王家林; 李平

    2009-01-01

    介绍了大型通用有限元软件ABAQUS的二次开发功能和利用面向对象语言Python编制参数化建模插件的原理和步骤.以变截面箱型桥梁参数化有限元建模为背景,通过ABAQUS提供的API函数和AFX GUI Toolkit工具包开发了箱梁桥参数化建模菜单和工具条,提高了箱型桥梁的有限元建模速度,为箱型桥梁的精细有限元分析提供了有力的支持.

  19. 昌平钢-混凝土结合连续刚构桥的设计与施工%Design and Construction of Steel and Concrete Continuous Composite Rigid Frame of Changping Overpass Bridge

    Institute of Scientific and Technical Information of China (English)

    马立芬; 王冰

    2012-01-01

    The Changping Overpass Bridge is a steel and concrete continuous composite rigid-frame bridge arranged in two continuous units, each being (37 + 60 + 79 + 42. 5) m and (42. 5 + 79 + 42. 5) m. The main girder of the bridge is designed as a steel and concrete composite one, of which the steel box girder is of the single-cell, single-box and vertical web section and the deck slabs are the reinforced concrete structure. The box girder is rigidly fixed with the concrete pier shaft at the intermediate pier and all pier columns of the bridge are the rectangular ones. The fi-nite element program MIDAS Civil was used to establish the calculation model for spatial struc-ture of the whole bridge, the static force of the bridge was calculated and analyzed and the results of the calculation and analysis proved that the stress and structural strength of the box girder could meet the relevant requirements in the codes. To minimize the interference of construction to the traffic under the bridge, the box girder was fabricated in shop and lifted in place at the bridge site. The precast deck slabs were installed by the discontinuous method in the sequence of the parts of the bridge at the midspan first and the parts close to the supports late.%昌平跨线桥采用两联跨度为(37+60+79+42.5)m及(42.5+79+42.5)m的钢-混凝土结合连续刚构型式.该桥主梁为钢-混凝土结合梁,钢箱梁采用单箱单室直腹板截面,桥面板为钢筋混凝土结构,钢箱梁在中墩处与混凝土墩身固结,下部结构墩柱均采用矩形桥墩.采用有限元程序MIDAS Civil建立全桥空间结构计算模型,对该桥进行静力计算分析,结果表明钢箱应力及结构强度均满足规范要求.为减少对桥下交通的影响,该桥钢箱梁采用工厂预制、现场吊装的方法施工,预制桥面板按先跨中后支点的顺序施工,采用间断法安装.

  20. 考虑缆-梁联合作用的自锚式悬索桥恒载状态计算方法研究%Study on the calculation method of the dead load state for the self-anchored suspension bridge considering the joint action of cable-stiffening girder

    Institute of Scientific and Technical Information of China (English)

    王邵锐; 周志祥; 高燕梅; 唐辉

    2015-01-01

    In most calculation methods for the reasonable finished bridge state of self-anchored suspension bridge, the combined action of cable-stiffening girder can not be considered in a single model, so repeated manual iteration or model boundary condition modification are usually adopted. For this reason, an analytical calculation method considering the combined action of cable-stiffening girder is proposed. Based on the stiffening girder deflection theory, the differential equilibrium equations, geometric equations, and the physical equations of the stiffening girder are used to derive the analytic relationship between the stiffening girder alignment and the suspender force. The end reaction force of the main cable is calculated from the suspender force using the segmental catenary theory. The solutions that meet the compatibility condition of the suspender force and the end reaction of the main cable is obtained by the iteration method. The calculation results by the proposed method agree well with the theoretical reasonable finished bridge state satisfying the principle of minimum potential energy of stiffening girder. The proposed method has the advantage of fast convergence speed and high precision that needed in practical engineering.%自锚式悬索桥合理成桥状态的已有算法中,很难在一个模型中同时考虑缆-梁的联合作用,需要通过反复手动迭代或是修改模型边界条件进行求解,较为繁琐。对此,笔者提出一种考虑缆-梁联合作用的恒载状态计算方法。该方法基于加劲梁的挠度理论,通过梁段的平衡微分方程、几何方程、物理方程推导出加劲梁的线形和索力的解析关系;主缆基于分段悬链线理论,通过已知吊索索力计算主缆端部反力;再用迭代方法得出满足以主缆端部反力和吊索索力为相容条件的解。计算结果表明,该方法能够考虑缆-梁联合作用,得到满足加劲梁最小应变

  1. Optimization Method for Girder of Wind Turbine Blade

    Directory of Open Access Journals (Sweden)

    Yuqiao Zheng

    2014-01-01

    Full Text Available This paper presents a recently developed numerical multidisciplinary optimization method for design of wind turbine blade. The objective was the highest possible blade weight under specified atmospheric conditions, determined by the design giving girder layer and location parameter. Wind turbine blade on box-section beams girder is calculated by ply thickness, main girder and trailing edge. In this study, a realistic 30 m blade from a 1.2 MW wind turbine model of blade girder parameters is established. The optimization evolves a structure which transforms along the length of the blade, changing from a design with spar caps at the maximum thickness and a trailing edge mass to a design with spar caps toward the tip. In addition, the cross-section structural properties and the modal characteristics of a 62 m rotor blade were predicted by the developed beam finite element. In summary, these findings indicate that the conventional structural layout of a wind turbine blade is suboptimal under the static load conditions, suggesting an opportunity to reduce blade weight and cost.

  2. A Proposal for 4000m-span Cable-stayed Suspension Bridge

    Directory of Open Access Journals (Sweden)

    Haijun Wang

    2013-06-01

    Full Text Available This study proposed a compound bridge of suspension bridges and cable-stayed bridges with 4000 m super-long-span over the Tsugaru Strait, Japan. Near to the main towers, cable-stayed bridges and prestressed concrete decks are proposed. It is helpful to enhance rigidity and endure the great axial compression force. In the center of the span, suspension bridges and steel box decks are stiffened by trusses, it can reduce self-weigh and the space between girders, thus contribute to aero-elastic stability. RCFT main tower, RC shell pier and RCFT jacket foundation can enhance rigidity and reduce self-weigh. As a result, the live-dead load ratio of proposal is 0.05 and it is equivalent to 2500m-span suspension bridge.

  3. The Design and Construction of 160T Girder Station%160T提梁站设计与施工

    Institute of Scientific and Technical Information of China (English)

    邓洪钧

    2012-01-01

      Guangshen Coastal Expressway Shenzhen Girder Station uses the steel pipe piles combined with Bailey girders in the construction.The headroom of the girder stations and the cast-in-place box girder is 7m, and the span is 17.25m. This paper makes a brief description of the installation method of the girder station%  广深沿江高速深圳段提梁站施工采用钢管桩结合贝雷梁形式。提梁站与现浇箱梁净空高度7m,跨度为17.25m,文章就提梁站的安装方法作简要介绍。

  4. Engineering approach to in-situ bridge health monitoring with fiber bragg gratings

    Institute of Scientific and Technical Information of China (English)

    WU Zhan-jun; ZHANG Bo-ming; WAN Li-bing; ZHOU Zhi; OU Jin-ping

    2006-01-01

    In this presentation the feasibility and capability of fiber Bragg gratings (FBG) employed in bridge health monitoring are demonstrated on a real bridge. FBG's wavelength shift depending on strain variance has been tested. The technique of FBG installation on bridges has been developed. 12 FBG strain sensors and 3temperature sensors have been successfully embedded in the prestressed concrete box girder during the construction of Heilongjiang Hulan River Bridge. The prestressing tension process and quasi-static loading process of the girder were monitored with those sensors before it was installed onto the bridge. After the bridge was completed,the FBG sensors embedded have been utilized to monitor the strain shift of the beam under quasi-static load,traffic load and temperature. The results show that the traffic fluxes, possible fatigue damage and deflection of the bridge can be revealed conveniently through strain measurements with these FBG sensors, which provide key information for structural health diagnosis. The fact that the FBG strain sensors have withstood the ordeal of harsh construction process and lasted for more than one year proves that their durability and stability can satisfy the requirements for bridge health monitoring. It is also shown that the FBG strain sensor is more adaptive to long-term structural health monitoring than the electric resistance strain gauge.

  5. A software prototype for assessing the reliability of a concrete bridge superstructure subjected to chloride-induced reinforcement corrosion

    DEFF Research Database (Denmark)

    Schneider, Ronald; Thöns, Sebastian; Fischer, Johannes

    2014-01-01

    A software prototype is developed for assessing and updating the reliability of single-cell prestressed concrete box girders subjected to chloride-induced reinforcement corrosion. The underlying system model consists of two integrated sub-models: a condition model for predicting the deterioration...... through Bayesian updating on the basis of the DBN model. To demonstrate the effect of partial inspections, the software prototype is applied to a case study of a typical highway bridge with six spans. The case study illustrates that it is possible to infer the condition of uninspected parts...... state of the box girder and a structural model for evaluating the overall system reliability. The condition model is based on a dynamic Bayesian network (DBN) model which considers the spatial variation of the corrosion process. Inspection data are included in the calculation of the system reliability...

  6. Wind Turbine Blade with Angled Girders

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to a reinforced blade for a wind turbine, particularly to a blade having a new arrangement of two or more girders in the blade, wherein each of the girders is connected to the upper part and the lower part of the shell and forms an angle with another girder thereby...

  7. Effect of vehicle weight on natural frequencies of bridges measured from traffic-induced vibration

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Recently, ambient vibration test (AVT) is widely used to estimate dynamic characteristics of large civil structures. Dynamic characteristics can be affected by various environmental factors such as humidity, intensity of wind, and temperature. Besides these environmental conditions, the mass of vehicles may change the measured values when traffic-induced vibration is used as a source of AVT for bridges. The effect of vehicle mass on dynamic characteristics is investigated through traffic-induced vibration tests on three bridges; (1) three-span suspension bridge (128m+404m+128m), (2) five-span continuous steel box girder bridge (59m+3@95m+59m), (3) simply supported plate girder bridge (46m). Acceleration histories of each measurement location under normal traffic are recorded for 30 minutes at field. These recorded histories are divided into individual vibrations and are combined into two groups according to the level of vibration; one by heavy vehicles such as trucks and buses and the other by light vehicles such as passenger cars. Separate processing of the two groups of signals shows that, for the middle and long-span bridges, the difference can be hardly detected, but, for the short span bridges whose mass is relatively small, the measured natural frequencies can change up to 5.4%.

  8. Distortional Buckling Analysis of Steel-Concrete Composite Girders in Negative Moment Area

    Directory of Open Access Journals (Sweden)

    Zhou Wangbao

    2014-01-01

    Full Text Available Distortional buckling is one of the most important buckling modes of the steel-concrete composite girder under negative moment. In this study, the equivalent lateral and torsional restraints of the bottom flange of a steel-concrete composite girder under negative moments due to variable axial forces are thoroughly investigated. The results show that there is a coupling effect between the applied forces and the lateral and torsional restraint of the bottom flange. Based on the calculation formula of lateral and torsional restraints, the critical buckling stress of I-steel-concrete composite girders and steel-concrete composite box girders under variable axial force is obtained. The critical bending moment of the steel-concrete composite girders can be further calculated. Compared to the traditional calculation methods of elastic foundation beam, the paper introduces an improved method, which considers coupling effect of the external loads and the foundation spring constraints of the bottom flange. Fifteen examples of the steel-concrete composite girders in different conditions are calculated. The calculation results show a good match between the hand calculation and the ANSYS finite element method, which validated that the analytic calculation method proposed in this paper is practical.

  9. Experiment study on fatigue behavior of composite girders with steel plate-concrete composite bridge decks%带钢板-混凝土组合桥面板的组合梁疲劳性能试验研究

    Institute of Scientific and Technical Information of China (English)

    杨勇; 周现伟; 薛建阳; 霍旭东

    2012-01-01

    In order to study the fatigue behaviour of the steel plate-concrete composite-deck composite girders under the fatigue load, constant-amplitude fatigue tests of six specimens of the steel plate-concrete composite-deck composite beam were carried out and static loading experiments of two specimens were conducted. The influence of the main factors including the upper and lower limits of fatigue load and the stress amplitude on the failure modes and the fatigue damage extent of composite girders under fatigue load were focused on. The dynamic deflection, strains of concrete and steel plates, strains of steel beam, residual deflection and residual bearing capacity were measured and analyzed. From the tests results, the fatigue life-spans of the composite girders specimens were directly related with their stress amplitudes, but the upper and lower limits of fatigue load had little effect. With regard to the fatigue failure modes of the composite girders specimens, positive moment composite girders were all failed due to collapse of the steel beam and crush of concrete of compressive zone, but not to the negative moment of composite girders, as a result of steel-beam buckling under static tests after fatigue tests. This paper were very helpful for this type of compsite girders design.%为研究带钢板-混凝土组合桥面板的组合梁在疲劳荷载下的受力性能,对2个试件进行静力试验研究,并对6个试件进行等幅疲劳试验研究。疲劳试验试件按承受正弯矩和承受负弯矩两组类型试件分别考虑,在各组试件中均主要考察疲劳荷载上、下限值及疲劳荷载幅值等因素对带钢板-混凝土组合桥面板组合梁的疲劳破坏模式及疲劳累积损伤的影响。疲劳试验过程中对组合梁试件在各主要循环加载次数下的动挠度、残余挠度、混凝土应变、底部钢板应变、试件钢梁应变及试件受弯刚度进行试验测量和分析。疲劳试验结果表明:正

  10. 运架一体式架梁机隧道架梁技术%Tunnel Girder Skill of Transported Frame Integrated Girder Machine

    Institute of Scientific and Technical Information of China (English)

    乐锋

    2013-01-01

      本文介绍了运架一体式架梁机的组成结构,施工前的各项准备工作。本文详细阐述了运架一体式架梁机进出隧道架设第一孔或最后一孔双线整孔预制箱梁的施工技术。%This article describes the structure composition of the transported frame integrated girder machine and the preparatory work before construction. This paper describes the double track prefabricated box girder construction technology of entering and going out the first or last hole of tunnel for the transported frame integrated girder machine.

  11. Field Tests and Simulation of Lion-Head River Bridge

    Directory of Open Access Journals (Sweden)

    Yao-Min Fang

    2007-01-01

    Full Text Available Lion-Head River Bridge is a twin bridge in parallel position. The east-bounded was designed and constructed as a traditional prestress concrete box girder bridge with pot bearings; and the west-bounded was installed with seismic isolation devices of lead rubber bearings. The behavior of the isolated bridge is compared with that of the traditional bridge through several field tests including the ambient vibration test, the force vibration test induced by shakers, the free vibration test induced by a push and fast release system, and the truck test. The bridges suffered from various extents of damage due to the Chi-Chi and the Chi-I earthquakes of great strength during the construction and had been retrofitted. The damage was reflected by the change of the bridges' natural frequencies obtained from the ambient vibration tests. The models of the two bridges are simulated by the finite element method based on the original design drawings. Soil-structure interaction was also scrutinized in this study. The simulation was then modified based on the results from the field tests. Dynamic parameters of bridges are identified and compared with those from theoretical simulation. The efficiency is also verified to be better for an isolated bridge.

  12. 既有损伤混凝土梁桥车桥耦动力分析%Study on dynamic behavior of vehicle-bridge coupling in existing concrete injured girder bridges

    Institute of Scientific and Technical Information of China (English)

    张萍; 张笑尘; 贾杰

    2016-01-01

    In order to carry out the systematic analysis of most highway concrete bridges’dynamic work performance under moving vehicular load with structural damages and their evolution,we put forward multi-scale analysis method and feasibility of vehicle-bridge coupling vibration with structural damages and analyze mechanism and influence law of bridges’dynamic behavior in this case.%以公路混凝土梁桥为研究对象,分析了结构损伤及损伤演化的车辆作用下桥梁动力的工作性能,提出考虑结构损伤的车桥耦合振动多尺度分析方法,探讨了该情况下桥梁动力行为的作用机理和影响规律。

  13. Structural Design of Multi-Pylon Cable-Stayed Bridge with Corrugated Steel Webs for Chaoyang Bridge in Nanchang%南昌朝阳大桥波形钢腹板多塔斜拉桥结构设计

    Institute of Scientific and Technical Information of China (English)

    陈水生; 钟志斌; 桂水荣; 刘旭政; 钟汉清

    2014-01-01

    The PC composite box girder with corrugated steel webs is applicable to bridges with a variety of structural types ,which exhibits superior durability and economic features as com‐pared with the common concrete box girder .The cable‐stayed bridge with corrugated steel webs is regarded as the type of structure where composite box girder with corrugated steel webs is ingen‐iously used ,making better use of the properties of the two structures . The main navigational bridge of the Chaoyang Bridge in Nanchang is a (79+ 5 × 150+79) m continuous composite box girder cable‐stayed bridge with corrugated steel webs .The bridge has six pylons and the stay ca‐bles are arranged in single cable plane .In addition ,the bridge has two layers of decks ,on the up‐per deck ,dual eight vehicle lanes (four lanes each side) are arranged and pedestrian and non‐mo‐torized vehicle lanes are arranged on the lower deck .Based on the analysis and study undertaken , small side span‐to‐main span ratio was chosen .Due to the multiple pylons ,the load path from the intermediate pylons to the side pylons is long and the effect of ancillary piers in the side spans is minimal ,as a result ,no ancillary piers are installed .In the structural system ,the pylons and the main girder are fixed while the girder and piers are separated .The box girder is 43 .84 m wide , with transverse steel diaphragms .The stay cables are fanned out in single cable plane .The pylon looks like the Chinese character“合“ ,and double bearings are installed at the pylons .T he stay vi‐bration mitigation bearings are used as the vibration mitigation and isolation devices of the super‐structure ,which are installed below the two side pylons .%波形钢腹板PC组合箱梁适用于不同结构形式的桥梁,相比普通混凝土箱梁具有显著的耐久性和经济性,波形钢腹板斜拉桥将波形钢腹板组合箱梁应用到斜拉桥中,充分发挥了2种结构的特点。南昌朝

  14. The Vibration Based Fatigue Damage Assessment of Steel and Steel Fiber Reinforced Concrete (SFRC Composite Girder

    Directory of Open Access Journals (Sweden)

    Xu Chen

    2015-01-01

    Full Text Available The steel-concrete composite girder has been usually applied in the bridge and building structures, mostly consisting of concrete slab, steel girder, and shear connector. The current fatigue damage assessment for the composite girder is largely based on the strain values and concrete crack features, which is time consuming and not stable. Hence the vibration-based fatigue damage assessment has been considered in this study. In detail, a steel-steel fiber reinforced concrete (SFRC composite girder was tested. The steel fiber reinforced concrete is usually considered for dealing with the concrete cracks in engineering practice. The composite girder was 3.3m long and 0.45m high. The fatigue load and impact excitation were applied on the specimen sequentially. According to the test results, the concrete crack development and global stiffness degradation during the fatigue test were relatively slow due to the favourable performance of SFRC in tension. But on the other hand, the vibration features varied significantly during the fatigue damage development. Generally, it confirmed the feasibility of executing fatigue damage assessment of composite bridge based on vibration method.

  15. Precast Prestressed Concrete Truss-Girder for Roof Applications

    Directory of Open Access Journals (Sweden)

    Peter Samir

    2014-01-01

    Full Text Available Steel trusses are the most popular system for supporting long-span roofs in commercial buildings, such as warehouses and aircraft hangars. There are several advantages of steel trusses, such as lightweight, ease of handling and erection, and geometric flexibility. However, they have some drawbacks, such as high material and maintenance cost, and low fire resistance. In this paper, a precast concrete truss is proposed as an alternative to steel trusses for spans up to 48 m (160 ft without intermediate supports. The proposed design is easy to produce and has lower construction and maintenance costs than steel trusses. The truss consists of two segments that are formed using standard bridge girder forms with block-outs in the web which result in having diagonals and vertical members and reduces girder weight. The two segments are then connected using a wet joint and post-tensioned longitudinally to form a crowned truss. The proposed design optimizes the truss-girder member locations, cross-sections, and material use. A 9 m (30 ft long truss specimen is constructed using self-consolidated concrete to investigate the constructability and structural capacity of the proposed design. A finite element analysis of the specimen is conducted to investigate stresses at truss diagonals, verticals, and connections. Testing results indicate the production and structural efficiency of the developed system.

  16. 客货共线1-156m简支钢桁结构分析%Structural analysis of 156 m simply supported steel truss girder

    Institute of Scientific and Technical Information of China (English)

    郝云杉

    2012-01-01

    The simply supported steel truss girder is widely used in railway bridge, because of definite stress, lower structural height, light weight and short construction period. Huanglin Hancheng Houma railway 156 m simply supported steel truss girder is the most span length in China. The bridge uses the triangle web member system without vertical members, which main truss members are box sections, the web members are box sections and H-shape sections. In the plane of the upper chords, the crisscross top lateral bracings are arranged which use I-shape sections. MIDAS Civil 2010 is use to establish the three-dimensional finite element model, calculate internal forces of main truss elements, stress, fatigue stress range and natural vibration period.%简支钢桁梁桥因其受力明确、结构高度低、自重轻以及施工周期短等优点,在铁路桥梁中得到了越来越广泛的采用.黄韩侯铁路单线l-156m栓焊下承式简支钢桁梁是目前国内最大跨度的简支钢桁梁结构.该桥主桁采用无竖杆的三角形腹杆体系,主桁弦杆均采用箱形截面;腹杆采用箱形截面和H形截面;上、下均采用交叉式平纵联,采用工字型截面.采用MIDAS Civil 2010建立该桥三维有限元模型,计算其主桁杆件内力、应力、疲劳应力幅,及全桥自振周期.

  17. A seismic performance evaluation method for a pile-foundation RC girder bridge considering three kinds of SSI effect%考虑SSI三种效应的桩基础RC梁式桥抗震性能评估方法研究

    Institute of Scientific and Technical Information of China (English)

    江辉; 李杰; 杨庆山; 朱晞; 刘林

    2012-01-01

    The dynamic interaction among pile-soil-bridge system is a hot spot and a difficult problem of aseismic design of bridges, and the flexible foundation effect, kinematics effect and foundation damping effect should be reasonably considered. Here, by introducing a seismic demand spectrum modification algorithm of kinematics interaction effect and foundation damping one with FEMA440, an aseismic performance evaluation method taking effectively three kinds of SSI effect for a pile-foundation RC girder bridge into account was developed based on structural nonlinear static analysis method. With a highway RC continuous girder bridge as an example, the nonlinear static and dynamic analysis were conducted respectively for the aim of comparison with three kinds of design spectra and the corresponding artificial waves as inputs. The results under two earthquake levels showed that the seismic response of the bridge taking the 2nd and the 3rd kinds of effect into account with the proposed method is slightly smaller than that of the bridge taking the 1st kind of effect into account with the dynamic time-history method, and the proposed method can be used to evaluate effectively the aseismic performance of a pile-foundation bridge under the anticipated earthquake demand.%桩-土-桥动力相互作用是桥梁抗震研究的热点和难点问题,需合理考虑地基土柔度效应、运动学效应及阻尼效应的影响.采用基于性能点轨迹法的结构非线性静力分析方法,引入FEM A440针对土-结相互作用运动学效应、地基阻尼效应的地震动需求谱修正算法,探讨建立综合考虑桩-土相互作用三种效应的桩基础RC桥梁的抗震性能评估方法.以某高速公路RC连续梁桥为算例,分别以三种设计谱及相应的人工波为输入进行非线性静、动力方法验算对比,两个水准下的计算结果表明所建议方法在补充考虑后两种效应后,地震响应略小于以考虑第一种效应为主

  18. 钢箱梁桥面板爆炸冲击响应数值模拟研究%Numerical simulation for response of a steel box girder deck to blast loading

    Institute of Scientific and Technical Information of China (English)

    蒋志刚; 白志海; 严波; 朱新明

    2012-01-01

    大跨度缆索承重桥梁遭受恐怖爆炸袭击的风险比一般桥梁大.运用LS-DYNA非线性有限元软件,研究了箱包炸弹和小轿车炸弹(TNT当量10~500 kg)桥面爆炸冲击作用下缆索承重桥梁钢箱梁正交异性桥面板的塑性变形、开裂与破口及耗能.结果表明:桥面板的主要耗能机制为盖板和加劲肋的塑性变形耗能,占爆炸输入能量的70%以上;加劲肋和横隔板对桥面板破口有约束作用,TNT当量为300~500 kg时,纵桥向破口尺寸小于等于横隔板间距,并小于横桥向破口尺寸.%Large span cable-supported bridges suffer greater risk of terrorful explosion than normal bridges do. The plastic deformation, rupture, tearing and energy dissipation of an orthotropic steel deck under blasting loads of hand-placed bombs and sedan bombs (TNT equivalent 10kg-500kg) were investigated with nonlinear finite element software LS-DYNA. The results showed that the bridge decks main energy dissipation mechanisms are the plastic deformation of cover plates and lengthways stiffeners, and the ratio of plastic deformation energy to explosion energy exceeds 70% ; the rupture of deck is constrained by the stiffeners and diaphragms, the lengths of ruptures in lengthways are not longer than the distance between two diaphragms, and shorter than those in width way while TNT equivalent is from 300kg to 500kg.

  19. Implementation and Non-Destructive Evaluation of Composite Structural Shapes in the Tom's Creek Bridge

    OpenAIRE

    Hayes, M. D.; J. Haramis; Lesko, John J.; Cousins, Thomas E.; J.C.Duke; Weyers, Richard E.

    2000-01-01

    A bridge rehabilitation utilizing a hybrid fiber reinforced polymeric composite has been completed in Blacksburg, Virginia. This project involved replacing the superstructure in the Tom's Creek Bridge, a rural short-span traffic bridge with a timber deck and corroded steel girders, with a glue-laminated timber deck on composite girders. In order to verify the bridge design and to address construction issues prior to the rehabilitation, a full-scale mock-up of the bridge was built and tested i...

  20. Powell's Optimal Identification of Material Constants of Thin-Walled Box Girders Based on Fibonacci Series Search Method%基于 Fibonacci 序列寻优理论薄壁弯箱材料常数的 Powell 优化识别

    Institute of Scientific and Technical Information of China (English)

    张剑; 叶见曙; 周储伟

    2011-01-01

    对于薄壁弯箱结构,推导了材料常数的动态 Bayes 误差函数,提出步长的一维 Fibonacci 序列自动寻优方案后,利用 Powell 优化理论研究了薄壁弯箱材料常数的动态识别方法,同时给出了具体的计算步骤,并研制了相应的计算程序.算例分析表明,Powell 理论用于弯箱材料常数识别时表现出良好的数值稳定性和收敛性,在迭代过程中,Powell 理论不涉及有限元偏导数处理,与以往材料常数的梯度优化方法相比,计算效率较高;建立的动态 Bayes 误差函数能同时计入系统参数的随机性和系统响应的随机性;提出的 Fibonacci 序列寻优方案无需通过试算确定最优步长所在区间,有效地解决最优步长的一维自动寻优问题.%For thin-walled curve box girders, dynamic Bayesian error function of material constants of the structure was founded. Combined with one-dimensional Fibonacci series automatic search scheme of optimal step length, the Powell' sop timization theory was utilized to perform the stochastic identification of material constants of thin-walled curve box. Then the steps of parameters' identification were presented in detail and the Powell' s identification procedure of martial constants of thin-walled curve box was compiled, in which the mechanical analysis of thin-walled curve box was completed based on finite curve strip element (FCSE) method.Through some classic examples, it is obtained that the Powell' s identification of material constants of thin-walled curve box has numerical stability and convergence, which demonstrates that the present method and the compiled procedure are correct and reliable. And during parameters' iterative processes, the Powell' s theory is irrelevant with the calculation of FCSE' s partial differentiation, which proves high computation efficiency of the studied methods. The stochastic performances of systematic parameters and systematic responses are simultaneously deliberated in

  1. Using BIM to Improve the Design and Construction of Bridge Projects: A Case Study of a Long-span Steel-box Arch Bridge Project

    OpenAIRE

    Wenping Liu; Hongling Guo; Heng Li; Yan Li

    2014-01-01

    More and more mega-complex bridge projects are being or will be built worldwide. At the same time, the design and construction of such projects involve more and more challenges, e.g., complex structural designs, complicated construction environments, etc. This research study aims to apply BIM (Building Information Modelling) to bridge projects to improve the efficiency and effectiveness of design and construction. Through the analysis of the characteristics of bridge projects and relevant, as...

  2. Design of Cable-Stayed Bridge of Caofeidian Industry Zone Bridge No.1%曹妃甸工业区1号桥斜拉桥设计

    Institute of Scientific and Technical Information of China (English)

    陈亮; 卢永成; 周伟翔; 邵长宇

    2011-01-01

    The Caofeidian Industry Zone Bridge No. 1 is composed of navigable span bridge, non-navigable span bridges and approach bridges and is located in the cold and strong earthquake region in the northern part of China. A summarized account of the design of the navigable span bridge of the bridge is presented herewith. In accordance with the construction conditions and landscape requirements, the navigable span bridge is designed as a single pylon and single cable plane cable-stayed bridge with span arrangement 2 X 138 m, the pylon is the column pylon in shape of boat sail. The anchorage zone in the pylon is the steel anchor box exposed outside the pylon. The main girder is the steel and concrete composite girder having three cells and a single box. The stay cables are made up of φ7 mm galvanized parallel steel wires and the foundation of the pylon pier is the group pile foundation. The research of seismic resistance of the bridge show that for a major single pylon cable-stayed bridge located in the strong earthquake region, the rigid fixity system of pylon, girder and pier should be possibly avoided in order to reduce seismic response of the bridge structure.%曹妃甸工业区1号桥位于北方寒冷强震区,由通航孔桥、非通航孔桥及引桥组成,综述该桥通航孔桥设计.根据建设条件及景观要求,通航孔桥为跨径2×138 m独塔单索面斜拉桥;桥塔为独柱形,造型为船帆式;索塔锚固区采用外露式钢锚箱方案;主梁采用单箱三室钢-混凝土箱形结合梁;斜拉索采用φ7 mm镀锌平行钢丝;桥塔墩采用群桩基础.抗震性能研究表明,强震区大型独塔斜拉桥应尽量避免采用塔、梁、墩固结体系,以减小桥梁结构的地震响应.

  3. Analysis on construction monitoring technology of a multispan variable cross -section continuous girder bridge%浅析某多跨变截面连续梁桥施工监控技术

    Institute of Scientific and Technical Information of China (English)

    俞梁友

    2016-01-01

    Discusses the combination of construction monitoring technology of variable cross section continuous beam bridge bridge,introduces the finite element model theory,alignment monitoring,stress control of the content,to provide reference for similar bridge construction monitoring.%结合某桥多跨变截面连续梁桥施工监控技术进行探讨,详细介绍了有限元模型建立理论、线形监控、应力监控等内容,为类似桥梁施工监测提供参考。

  4. Using BIM to Improve the Design and Construction of Bridge Projects: A Case Study of a Long-span Steel-box Arch Bridge Project

    Directory of Open Access Journals (Sweden)

    Wenping Liu

    2014-08-01

    Full Text Available More and more mega-complex bridge projects are being or will be built worldwide. At the same time, the design and construction of such projects involve more and more challenges, e.g., complex structural designs, complicated construction environments, etc. This research study aims to apply BIM (Building Information Modelling to bridge projects to improve the efficiency and effectiveness of design and construction. Through the analysis of the characteristics of bridge projects and relevant, associated problems, a BIM-based solution to improving design and construction is developed, including conceptual design optimization, detailed design optimization, the optimization of construction sequences, construction scheduling, construction management, and construction process monitoring. Furthermore, a real-life bridge project is presented to demonstrate the feasibility and validity of the BIM-aided approach to design and construction. It is shown that BIM has the potential to improve the design and construction of bridge projects. It is expected that this research could contribute to the extensive application of BIM in mega-complex bridge projects to aid in design and construction in the future.

  5. 港珠澳大桥青州航道桥工程特点及关键技术%Engineering Characteristics and Key Techniques of Qingzhou Ship Channel Bridge of Hong Kong-Zhuhai-Macao Bridge

    Institute of Scientific and Technical Information of China (English)

    刘明虎; 孟凡超; 李国亮

    2013-01-01

    The Qingzhou Ship Channel Bridge of the Hong Kong-Zhuhai-Macao Bridge is a steel box girder cable-stayed bridge with double pylons and double cable planes.In the design of the bridge,a variety of the new materials,new techniques and new workmanships have been applied.In this paper,the engineering characteristics and key techniques of the bridge are summarized.On the bridge,the steel box girders of the same structural types of the adjacent non-navigable span bridges are fully used as the counterweight and on the outer side spans of the bridge,the stay cables are not installed.The arrangement of the bridge in such a way is well appropriate to the local conditions of the bridge site and has notable comprehensive advantage.The structural support system of the bridge is the three-way system that can ensure the structural performance of the whole bridge to be optimal.The pylons have the crisscross steel struts of the “Chinese Knot” configuration,which are connected with the concrete pylon columns via the connecting boxes in a combined force transmitting mode of “ compression-shear” and the performance of the steel struts and connection is safe and reliable.The foundations for the bridge are the composite piles of variable diameter steel pipes and together with the reinforced concrete in the steel pipes,the composite sections of the piles that are to jointly bear the loads and are cost-saving and rational are formed.The pier shafts are formed by the precast segments.The segments are installed at the site and are connected each other by the φ75 mm thick prestressing bars.The steel box girders are of the optimized streamlined flat sections topped with the orthotropic steel deck plates and the fatigue performance of the girders are quite superior.The stay cables are the ones made up of the parallel steel wires and having tensile strength of 1 860 MPa.%港珠澳大桥青州航道桥为双塔双索面钢箱梁斜拉桥,该桥设计采用了多项新材料、新技术

  6. Experimental Evaluation of the Post-ultimate Strength Behavior of a Ship's Hull Girder in Waves

    Institute of Scientific and Technical Information of China (English)

    Weijun Xu; Kazuhiro Iijima; Ryota Wada; Masahiko Fujikubo

    2012-01-01

    Experimental investigations into the collapse behavior of a box-shape hull girder subjected to extreme wave-induced loads are presented.The experiment was performed using a scaled model in a tank.In the middle of the scaled model,sacrificial specimens with circular pillar and trough shapes which respectively show different bending moment-displacement characteristics were mounted to compare the dynamic collapse characteristics of the hull girder in waves.The specimens were designed by using finite element (FE)-analysis.Prior to the tank tests,static four-point-bending tests were conducted to detect the load-carrying capacity of the hull girder.It was shown that the load-carrying capacity of a ship including reduction of the capacity after theultimate strength can be reproduced experimentally by employing the trough type specimens.Tank tests using these specimens were performed under a focused wave in which the hull girder collapses under once and repetitive focused waves.It was shown from the multiple collapse tests that the increase rate of collapse becomes higher once the load-carrying capacity enters the reduction path while the increase rate is lower before reaching the ultimate strength.

  7. Multiplexed Bragg grating optical fiber sensors for damage evaluation in highway bridges

    Science.gov (United States)

    Idriss, R. L.; Kodindouma, M. B.; Kersey, A. D.; Davis, M. A.

    1998-04-01

    A multiplexed Bragg grating optical fiber monitoring system is designed and integrated at the construction stage in an experimental full scale laboratory bridge. The test bridge is a 40 ft span non-composite steel girder concrete deck bridge. The network of sensors is used to measure the strain throughout the bridge, with sensors bonded to the tension steel in the slab and attached to the bottom flange of the girders. Resistive strain gages and Bragg grating sensors are placed side by side to compare results. The strain data are obtained for the pristine structure, then damage is introduced at midspan for an exterior girder. Several levels of damage in the form of cuts in one of the girders are imposed with the final cut resulting in a half depth fracture of the girder. The load path in the structure is obtained using the built in sensor system.

  8. On flutter stability of decks for super long-span bridge; Cho chodai tsurihashi hogoko no furatta anteika ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, M. [Kyoto Univ. (Japan). Faculty of Engineering; Hamazaki, H. [Fuji Research Inst. Corp., Tokyo (Japan); Yoshizumi, F. [Kyoto Univ., Kyoto (Japan). Graduate School

    1996-04-21

    In recent years, with the development of high strength steel, long span suspension-bridge becomes possible, furthermore, with the progress of welding technology, the horizontal deformation and torsional deformation of the deck increase owing to the reduction of energy dissipation due to sliding friction. Because of this, super long-span bridge is easy to get vibrated by wind, stability measures having more excellent wind resistance become necessary. In this study, aiming at controlling the pattern of air flow around the sections of box-form girder of super long-span bridge, studied were conducted on deck sections having more excellent flutter stability. Studied were conducted on the relationship between torsional vibration and flexible vibration coupled with unsteady aerodynamic force coefficience at the occurrence of flutter and the occurring mechanism of the flutter was cleared. The characteristics of the aerodynamic force of box-form girder having oval section, rectangle section with center barrier, anti-triangle section and tandem oval section respectively were studied and the results were reported. 10 refs., 25 figs.

  9. Hollow plate girder bridge damaged hinge joints on the transverse distribution%空心板梁桥铰缝损坏对横向分布的影响

    Institute of Scientific and Technical Information of China (English)

    张立东; 孙全胜

    2015-01-01

    Through the hollow beam superstructure disease research found that very serious damage to the hinge joints. Due to changes in the stiff-ness of the hinge joints caused a bridge overall force changes that may even force the board features. With the help of Midas civil finite element analysis software to establish the finite element model to analyze the impact of the bridge damaged hinge joints transverse distribution can provide a theoretical basis for the kind of bridge maintenance and reinforcement of hinge joints.%通过对空心板梁上部结构病害调查研究发现,铰缝破坏现象十分严重,由于铰缝刚度发生变化造成了桥梁整体受力变化,甚至可能出现单板受力特征,借助Midas civil有限元分析软件建立了有限元模型,分析了铰缝损坏对桥梁横向分布的影响,可为同类桥梁铰缝维修与加固提供理论依据。

  10. Key Techniques for Design of Edong Changjiang River Highway Bridge%鄂东长江公路大桥设计关键技术

    Institute of Scientific and Technical Information of China (English)

    胡明义; 黄冰释; 余俊林; 唐守峰

    2011-01-01

    The main bridge of Edong Changjiang River Highway Bridge is a semi-floating system hybrid girder cable-stayed bridge with double pylons, double cable planes and with a main span 926 m. The main girder of the bridge was designed as the PK (Pasco-Kennewick Bridge) cross section of separated twin boxes, of which the part of the girder for the central span is of the steel box girder, the parts of the girder for the side spans are of the prestressed concrete (PC) box girders and a steel and concrete joint section was set on each side of the central span at a distance of 12. 5 m to the center of a pylon. To ensure a smooth transition between the steel and concrete structure, the multi-cell force transmission structure with PBL shear connectors was used for the joint section. The cable-to-pylon anchorage is the steel anchor box structure built in the column of a pylon. To control the development of concrete cracks in the anchorage zone in the pylon, the prestressing strands of 12φs 15. 24 were set in the concrete pylon wall on the side of the anchorage. To enhance the structural durability and service life, the durability of reinforced concrete and corrosion protection of steel structure were designed and the life cycle cost concept was applide to the design. The inspection and maintenance accesses for all principal components of the bridge were provided and the inspection and maintenance cycles, replacement criteria, workmanship and technical requirements were formulated as well.%鄂东长江公路大桥主桥为主跨926 m的双塔双索面半飘浮体系混合梁斜拉桥,主梁采用分离式双箱PK断面形式,中跨为钢箱梁,边跨为PC箱梁,钢-混凝土结合段设于中跨距桥塔中心12.5m处.为使钢结构与混凝土结构平稳过渡,钢-混凝土结合段采用PBL剪力连接器的多格室传力构造.索塔锚固采用在塔柱内置钢锚箱的构造,为控制锚固区混凝土裂缝开展,在锚固侧混凝土塔壁内设置12(o)s15.24预应力

  11. 钢箱梁正交异性桥面板球扁钢纵肋球头朝向和黄隔板空孔的优化%Optimization of Bulb Direction and Diaphragm Cutout of Bulb Flat Ribs in Steel Orthotropic Deck of Box Girder

    Institute of Scientific and Technical Information of China (English)

    吴臻旺; 郑凯锋; 税彦斌; 张昊

    2011-01-01

    某钢箱梁正交异性桥面板行车道范围内采用球扁钢纵肋,在横隔板对应部位设置空孔让纵肋连续通过,为研究横隔板的空孔圆弧、空孔与纵肋连接端部等两个细节部位的受力特性,以某立交桥F匝道为工程背景,建立全桥有限元模型,对称荷载作用,对比横隔板对称位置空孔应力分布,分析纵肋球头朝向和背对邻近腹板两种布置对空孔受力的影响.荷栽位于不同横向位置,分析横隔板空孔面内受力.荷载位于不同纵向位置,分析横隔板空孔面外受力.对横隔板空孔圆弧半径进行参数分析.研究表明,球扁钢纵肋球头背对邻近腹板和适当增大空孔圆弧半径等措施,可明显改善横隔板空孔圆弧部位受力,但对空孔与纵肋连接端部效果不够明显,需采取进一步措施以改善该细节部位的受力性能.%Bulb flat ribs were used in the range of driveways on the steel orthotropic deck of a box girder, and cutout was set on the diaphragm to let the longitudinal ribs to pass through continuously. In order to probe into the stress characteristics of two details of diaphragm cutout, such as arc of cutout and its joint to rib, finite element analysis was carried out based on the ramp F of an overpass. With the symmetrical vehicle load action, stress distributions of symmetrical cutouts were compared, and the influences of bulb towards and/or back against the adjacent web plate on the stress characteristics of the cutout were studied respectively. For different transverse positions of vehicle load, the in-plane stress characteristics of diaphragm cutout were studied. For different longitudinal positions of vehicle load, the out-of-plane stress characteristics of diaphragm cutout were studied. Then, the parameter optimization of arc radius of cutout was carried out. The results show that the stress along the arc of the diaphragm cutout will be more appropriate when the bulb of longitudinal ribs is back

  12. Plastic analysis of the lateral effective width of cantilever slabs of reinforced concrete box-girders%基于塑性分析的钢筋混凝土箱梁悬臂板横向受力有效分布宽度

    Institute of Scientific and Technical Information of China (English)

    方志; 郑辉; 刘双阳

    2012-01-01

    目前国内外相关设计规范中关于行车道板横向受力有效分布宽度的取值是基于弹性理论分析结果确定的,不能体现塑性阶段行车道板横向受力特点。通过对2个钢筋混凝土箱梁模型上的4块悬臂板进行荷载试验,得出悬臂板极限荷载和塑性铰线分布形式,并运用塑性分析方法,推导钢筋混凝土箱梁悬臂板在局部荷载作用下塑性有效分布宽度的计算公式。试验结果和理论分析比较表明:悬臂板的塑性有效分布宽度与荷载作用位置及单位板宽正、负极限弯矩值相关;满足构造配筋要求的箱梁悬臂板进行极限状态设计时,建议采用简化的三折线破坏模式进行塑性横向有效分布宽度计算,取正铰线扩散角为45°,负铰线扩散角为60°;荷载作用于悬臂板边缘时基于塑性的横向有效分布宽度是基于弹性分析的1.58倍。%According to the current design code specifications home and abroad, the values of effective width are mostly based on the results of elasticity theory, which cannot represent the characteristics of effective width in the plastic stage. The ultimate load capacity of cantilever slab and the distribution form of plastic yield-lines were acquired through loading experiments of four cantilever slabs of two reinforced concrete box-girders. The formula for calculating the effective width of the slabs under patch load was derived from plastic analysis. By comparing the experimental results with that of theoretical analysis, it is found that the plastic effective width depends on the load-bearing position and both the positive and negative values of ultimate moment, in addition, the simplified tri-linear mode could effectively determine the ultimate strength and plastic effective width of the slabs with at least the minimum reinforcement, and the desirable calculation plastic spread angle is 45~ for the positive yield-line, 60~ for the negative yield

  13. 基于UHPC的超大跨径桥梁优化设计%Optimal Design of Ultra-long Span Bridge Based on UHPC

    Institute of Scientific and Technical Information of China (English)

    闫军祥

    2016-01-01

    In order to solve the problems in long span bridge of conventional concrete, such as easily cracking of box girder, limited span (under 300 m), Ultra-high Performance Concrete (UHPC) has been introduced to the design of ultra-long span bridge. A new type structure of continuous box girder contain thin-wall structure and dense diaphragm plates has been design. Obtain the optimal distance is 4m of dense diaphragm plates and optimal span ratio is 0.6 through performance analysis and optimization design. Research finding the UHPC bridge has the advantages of strong sustainability, long service life through contrastive analysis of UHPC bridge design scheme and entity arch bridge. The design of UHPC bridge provide a new method for ultra-long continuous box girder bridge.%为了解决常规混凝土下大跨径桥梁出现的箱梁易开裂,主跨径难以突破300 m等问题,将超高性能混凝土(ultra-high performance concrete,UHPC)引用至超大跨径的桥梁设计当中,形成了一种集薄壁结构、密集横隔板箱梁于一体的新型连续梁结构,并对横隔板参数和跨径比进行优化,确定最佳横隔板间隔为4 m,跨径比为0.6。将UHPC箱体桥梁设计方案与某实体桥梁进行对比分析,发现UHPC桥梁具有可持续性强、使用寿命长等优点,为超大跨径连续箱体桥梁设计提供了一个新的方法。

  14. 不中断交通维修加固板梁桥铰缝病害处治方案%Treatment Scheme of the Hinge Joint Hazard in the Maintenance and Reinforcement of Plate Girder Bridge without Interrupting Traffic

    Institute of Scientific and Technical Information of China (English)

    左智

    2014-01-01

    Along with the improvement of the life quality of people, people require more for the convenience of traffic tra-vel. In this paper, under the uninterrupted traffic situations, the author discussed the construction technology of repairing the hinge joint of hol ow plate of bridge.%随着全民生活品质的提高,人们对于出行交通的便捷要求更高了。本文对在不中断交通的情况下,如何进行桥梁空心板铰缝修复的施工工艺做了重点阐述。

  15. Improving the Dynamics of Suspension Bridges using Active Control Systems

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Improving the dynamics of suspension bridge using active control is discussed in this paper. The main dynamic problem with long suspension bridges is the aeroelastic phenomenon called flutter. Flutter oscillations of a bridge girder is a stability problem and the oscillations are perpendicular...

  16. Committee VI.1. Extreme Hull Girder Loading

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    2000-01-01

    Committee Mandate. Evaluate and develop direct calculation procedures for extreme wawe loads on ship hull girders. Due consideration shall be given to stochastic and non-linear effects. The procedures shall be assessed by comparison with in-service experiences, model tests and more refined...

  17. 空间曲梁单边悬索桥圆弧形钢箱梁的安装%Installation of Circular Arc Steel Box Girder for Space Curved Beam Unilateral Suspension Bridge

    Institute of Scientific and Technical Information of China (English)

    王星; 阮再兴

    2015-01-01

    以上海国际旅游度假区空间曲梁单边悬索桥的圆弧形钢箱梁现场安装工艺为背景,对施工技术要素进行分析,阐述了圆弧形钢箱梁安装施工的特点和难点.通过采取临时支架法和钢箱梁分节段吊装等施工措施,为圆弧形钢箱梁的现场顺利施工提供了技术保证.

  18. Analysis on Transverse Effect of Urban Elevated Bridge with Broad Box Girders of Arc Bottom%城市高架弧形底宽箱梁桥横向效应分析

    Institute of Scientific and Technical Information of China (English)

    陆光闾; 曹中银; 徐科英; 秘志辉

    2004-01-01

    以上海市沪闵路高架道路二期工程弧形底宽箱梁工程为研究对象,以有限元法分析了箱梁断面在自重和外荷载作用下的断面横向效应,分析探讨了墩顶横梁刚度、支承间的横向距离及腹板厚度对横向应力的影响,可供桥梁结构设计参考.

  19. 砼连续箱梁人行天桥振动特性测试与分析%Vibration characteristics test and analysis on concrete box girder continuous pedestrian bridge

    Institute of Scientific and Technical Information of China (English)

    张冠华; 葛耀君

    2009-01-01

    以某座普通钢筋砼连续箱梁人行天桥为工程背景,通过对其振动特性进行大量实测试验,利用有限元理论对结构整体进行计算,深入分析其大幅度竖向、侧向振动的成因,结合实测数据探讨现行人行桥振动舒适度评价方法所存在的不足之处,评价天桥的舒适程度,为该桥的质量检测与评价提供依据,并提出了人行天桥振动舒适性评价建议.这为今后对该类桥梁的设计、维修加固具有实际参考价值.

  20. Research of the Virtual Beam Spacing during Modeling Virtual Beams of Small Box-Girder Bridge%小箱梁桥虚拟横梁建模法中虚横梁间距选取研究

    Institute of Scientific and Technical Information of China (English)

    葛素娟; 李静斌

    2009-01-01

    利用大型有限元通用软件MIDAS对40 m跨小箱梁桥建立实体单元模型和虚拟横梁单元模型,针对不同虚横梁间距模型分别计算了6种荷载工况下的跨中竖向位移,并与实体单元模型跨中竖向位移相比较,得出虚横梁问距为1/10~1/8跨长时,与实体单元的误差最小,建模时依据该结论取虚横梁间距.此结论也可以供其他跨径小箱梁桥建模计算时参考.

  1. 梁格法分析小箱梁桥虚拟横梁刚度模拟%Virtual beam stiffness simulation of grillage method analysis of small box girder bridge

    Institute of Scientific and Technical Information of China (English)

    冯文焕; 苏巨峰

    2013-01-01

    采用梁格法分析小箱梁桥时,为了简便准确的模拟虚拟横梁刚度,根据小箱梁桥的横向构造提出一种分段式模拟虚拟横梁的方法,并以一跨30 m简支小箱梁桥为例,通过与板单元模型计算结果对比,验证了这种方法的有效性和准确性.

  2. Design and construction of form for 70m box girder of Donghai Bridge%东海大桥非通航孔70 m箱梁模板设计与施工

    Institute of Scientific and Technical Information of China (English)

    黄少文; 沈阳云

    2005-01-01

    东海大桥非通航孔70 m箱梁在预制场整体预制,模板设计采用美国SYMONS公司先进的设计理念.介绍了70 m箱梁模板的底模、外模和内模的结构和布置,并对外模和内模的安装和拆除步骤作了详细说明.

  3. 移动支架造桥机箱梁节段拼装施工技术%Construction technology of box-girder segment bricolage of traversing carriage bridge fabrication machine

    Institute of Scientific and Technical Information of China (English)

    杨江朋

    2009-01-01

    结合赣龙铁路16标段森坑一号大桥采用ZQJ-32/56移动支架造桥机施工实例,介绍了箱梁节段拼装法的施工特点,施工技术以及控制措施等,为桥梁建设提供了一种很好的施工方法.

  4. Fatigue Evaluation of Sutong Bridge Based on Actual Measurement%基于实测的苏通大桥疲劳寿命评估

    Institute of Scientific and Technical Information of China (English)

    曹硕; 张启伟

    2011-01-01

    通过分析苏通大桥钢箱梁疲劳关键部位的实测应变时程,研究了其在正常运营阶段的应力谱的特征和疲劳状况预测.由测得的应力时程可知,绝大部分时刻的应变值都在40με以内,但重车过桥时的瞬时应变值可达120με,远大于一般车辆.由应力谱分析可知,苏通大桥钢箱梁顶板及索梁钢锚箱处应力水平较高.由名义应力法计算可知,苏通大桥钢箱梁疲劳寿命最短的部位为顶板与U肋焊缝,为188年.以目前的交通量和结构状况,苏通大桥不会发生疲劳破坏.%Through analyzing measured strain-time data of typical fatigue places on Sutong bridge, this paper studies its stress spectrum characters under daily traffic and predicts its fatigue life. Measured strain time-data shows that at most times its strain is below 40 με, but instantaneous strain can reach 120 μe when heavy trucks pass the bridge. Through analyzing stress spectrum, it can be seen that roof of the box girder and cablegirder anchor box own higher stress level. Using nominal stress method, the shortest fatigue life of box girder of Sutong bridge is 188 years and the most dangerous place locates at the weld joint of roof and U-shaped rib.In sum, Sutong bridge won' t occur fatigue failure under present tratfie and structure situation.

  5. 海洋环境下预应力混凝土桥梁耐久性分析与设计%Durability Analysis and Design of Prestressed Concrete Girder Bridge in Marine Environment

    Institute of Scientific and Technical Information of China (English)

    李成绩; 陆春华

    2012-01-01

    In order to study the durability behavior of concrete structure caused by chloride attack in marine environment,a calculated model for chloride ingress in prestressed concrete is built,which mainly takes material property,environment,stress level of concrete and surface convection into account.Then,considering the character of durability failure for presstressed concrete bridge structure,the durability limit state is defined as the initiation of prestressing steel's corrosion.Based on the statistic results of relevant random variables,the reliability indexes under various water-binder ratio and cover thickness are studied with Monte-Carlo simulation;and the minimum cover thickness are proposed to satisfy certain target reliability index.Analytical results can provide some reference to engineering durability design.%为了研究海洋环境下氯离子侵蚀引起的混凝土结构耐久性行为,在重点考虑材料、环境、混凝土应力水平以及表层对流区影响的基础上,建立了预应力混凝土氯离子侵入扩散模型;随后,基于预应力混凝土桥梁结构耐久性失效的特点,提出了以预应力筋临界锈蚀作为耐久性极限状态的标志;并在各随机变量统计分析的基础上,采用Monte-Carlo方法研究了不同水胶比、不同保护层厚度时的可靠指标变化情况,得出了给定目标可靠指标下预应力筋的最小保护层厚度。相关研究成果可以为工程设计提供一定参考。

  6. Full scale strain monitoring of a suspension bridge using high performance distributed fiber optic sensors

    Science.gov (United States)

    Xu, Jinlong; Dong, Yongkang; Zhang, Zhaohui; Li, Shunlong; He, Shaoyang; Li, Hui

    2016-12-01

    This paper investigated field monitoring of a 1108 m suspension bridge during an assessment load test, using integrated distributed fibre-optic sensors (DFOSs). In addition to the conventional Brillouin time domain analysis system, a high spatial resolution Brillouin system using the differential pulse-width pair (DPP) technique was adopted. Temperature compensation was achieved using a Raman distributed temperature sensing system. This is the first full scale field application of DFOSs using the Brillouin time domain analysis technique in a thousand-meter-scale suspension bridge. Measured strain distributions along the whole length of the bridge were presented. The interaction between the main cables and the steel-box-girder was highlighted. The Brillouin fibre-optic monitoring systems exhibited great facility for the purposes of long distance distributed strain monitoring, with up to 0.05 m spatial resolution, and 0.01 m/point sampling interval. The performance of the Brillouin system using DPP technique was discussed. The measured data was also employed for assessing bridge design and for the assessment of structural condition. The results show that the symmetrical design assumptions were consistent with the actual bridge, and that the strain values along the whole bridge were within the safety range. This trial field study serves as an example, demonstrating the feasibility of highly dense strain and temperature measurement for large scale civil infrastructures using integrated DFOSs.

  7. Strengthening and repair of steel-concrete composite girders using CFRP laminates

    Science.gov (United States)

    Tavakkolizadeh, Mohammadreza

    The use of advanced composite materials for rehabilitation and repair of deteriorating infrastructure has been embraced worldwide. The conventional techniques for strengthening of substandard bridges are costly, time consuming and labor intensive. A total of 38 specimens made of steel and carbon fibers were prepared and tested to investigate the possibility of galvanic corrosion. Two simulated aggressive environments and three different amounts of epoxy coating were used. Potentiodynamic polarization and galvanic corrosion tests were conducted. The results of the experiments showed the existence of galvanic corrosion however the rate of such corrosion could be decreased significantly by epoxy coating. A total of 21 specimens made of S 5 x 10 A36 steel beams were prepared and tested to determine the effectiveness of CFRP patch on fatigue life of notched beam. The results showed that not only CFRP patch tends to extend the fatigue life of a detail more than three times, but also it decreases the crack growth rate significantly. To investigate the effectiveness of the epoxy bonded CFRP sheets in repair and retrofit of composite girders, a total of six large-scale steel-concrete composite girders made of W 14 x 30 A36 steel beam and 7.5 cm. thick by 91 cm wide concrete slab were prepared and tested. Three different numbers of CFRP layers and three different damage level in Range were considered. The retrofitting test results showed that epoxy bonded CFRP Sheet increased the ultimate load carrying capacity of composite girders and the behavior can be conservatively predicted by traditional methods. The repair test results showed that epoxy bonded CFRP sheet could restore the ultimate load carrying capacity and stiffness of damaged steel-concrete composite girders. The ultimate capacity of the repaired beam was predicted by traditional methods of analysis of steel-concrete composite beams, which was fairly conservative. Guidelines and procedures for design of Steel

  8. Continuous Beam Cantilever of the Luoqing jiang Casting Construction Technology River Extra-large Bridge%洛清江特大桥连续梁悬臂灌筑施工技术

    Institute of Scientific and Technical Information of China (English)

    李锟

    2011-01-01

    This paper makes an explanation about construction technology for bridge segment No. O, the cantilever casting segment, the cast-in-situ segment and the closure segment under cantilever casting construction of the Luoqingjiang extralarge bridge which is of pre-stressed continuous box girder type. It sums up the key technology for construction of continuous beam of the Luoqingjiang extra-large double line bridge.%详细介绍洛清江双线特大桥预应力砼连续箱梁悬臂灌筑的0号号段、悬灌段、现浇段及合龙段施工技术,从而总结出洛清江双线特大桥连续梁关键施工技术。

  9. Finite Element Analysis of the Effect of Crack Depth and Crack Opening On the Girder

    Directory of Open Access Journals (Sweden)

    Md. Kamrul Hassan

    2011-01-01

    Full Text Available In order to identify the effect of crack depth and opening on the girder, finite element method (FEM has been used in this paper. In FE analysis, six nodded two dimensional plane elements (PLANE-2 are considered. Each node has two degree of freedom such as UX and UY. For the plane elements, a plane stress width/thickness option is chosen. For analytical model of crack of the concrete bridge girder, crack opening was increased from 0.2 mm to 1mm at an interval 0.2 mm and crack depth also increased from 30 mm to 150 mm at an interval 30 mm. The models were discreatized by a triangular mesh and convergence test was executed to obtain satisfactory results from the Plane-2 element. From the numerical result, it is seen that the principal stress become a higher with increased the crack depth and also crack opening with respect to load increasing. But the crack depth at 90 mm and crack opening at 0.6 mm, it has more effect on the girder because the stress concentration is higher than other crack depth and opening.

  10. Construction Schemes for Main Bridge of Taohuayu Huanghe River Bridge on Wuzhi-Xixia Expressway%武西高速桃花峪黄河大桥主桥施工方案

    Institute of Scientific and Technical Information of China (English)

    金雷

    2011-01-01

    桃花峪黄河大桥主桥为双塔三跨自锚式悬索桥,跨度布置为(160+406+160) m.桥塔为门式混凝土结构,加劲梁为流线型钢箱梁,主缆采用高强镀锌钢丝预制平行索股.结合该桥主体结构特点和桥位处施工条件,桩基采用旋挖钻机与回旋钻机结合施工,水中承台采用钢管桩围堰施工,岸边承台采用大开挖配合深井降水施工;塔柱采用液压自升式爬模施工,塔柱上横梁采用托架法施工,下横梁采用支架法施工;上部结构采用先梁后缆顺序施工,加劲梁利用单向多点顶推计算机控制系统进行各点同步顶推施工,与钢锚梁合龙后采用PPWS法施工主缆,主缆完成体系转换后进行桥面系施工.%The main bridge of Taohuayu Huanghe River Bridge is a two-tower and three-span self-anchored suspension bridge with span arrangement (160+406+ 160) m. The towers of the bridge are the concrete portal frames, the stiffening girder is the streamlined steel box girder and the high strength galvanized prefabricated parallel wire strands (PPWS) are used for the main cables. In the light of the characteristics of the principal structure of the bridge and the construction conditions at the bridge site, the pile foundations were constructed by the combined application of rotary boring machine and abrasion boring machine, the in-water pile caps by the steel pipe pile cofferdams and the pile caps nearby the river banks by the mass excavation combined with the deep well dewatering. The tower columns were constructed by the hydraulic self-climbing formwork, the upper cross beams of the columns by the bracketing method and the lower cross beams by the scaffolding method. The superstructure was constructed by the sequence of “erecting the girder first and cables late”. The stiffening girder was erected by the one-way, multi-point and synchronous incremental launching controlled by computer system and after the girder was closed with the steel anchor

  11. Design of T-Frame Bridge of Mashui River Bridge%马水河特大桥T形刚构桥设计

    Institute of Scientific and Technical Information of China (English)

    陈晓波

    2011-01-01

    Mashui River Bridge is a long span T-frame bridge with span arrangement (116 +116) m. The main girder of the bridge is a prestressed concrete girder of variable section, having a single cell single box and vertical webs. The top of the girder is 10.7 m in width and the bottom varies in round arc. The main pier of the bridge is 108 m high and the pier shaft is the high-rise rectangular hollow pier that has no solid section close to the top of the pier and is connected with the girder in a way of spatial frame. The foundation for the pier is composed of 24 nos. of φ2.5 m reinforced concrete bored piles, the concrete for the piles is of C30 and a 7.5 m high training dike is set at the footing of the pier. The BSAS and ANSYS are respectively used to conduct the structural static force calculation and spatial static and dynamic force analysis. The results of the calculation and analysis show that the static force, wind resistance, seismic resistance and dynamic response of the vehicle and bridge can all satisfy the relevant requirements in the codes. The pier shaft of the bridge is constructed by the backward inclined cantilever formwork and the main girder is constructed by the free balanced cantilever concreting method.%马水河特大桥为(116+116)m的大跨度T形刚构桥.主梁采用变截面预应力混凝土箱梁,单箱单室直腹板,箱梁顶宽10.7 m,梁底缘按圆弧变化.主墩高108 m,墩身采用矩形空心高墩,墩顶不设实体段,与梁部按空间框架形式相接,桩基采用24-φ2.5 m钢筋混凝土钻孔桩,混凝土强度等级为C30,在墩底设置7.5 m高的导流堤.分别采用BSAS和ANSYS对全桥进行结构静力计算及空间静力和动力分析.分析结果表明:该桥静力、抗风、抗震、车桥动力响应验算结果均满足规范要求.该桥主墩墩身采用后倾式悬臂模板法施工,主梁采用对称悬臂浇筑法施工.

  12. Construction and control technology of the main bridge superstructure of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Hong; Luo Chenbin; Zhang Yongtao; You Xinpeng

    2009-01-01

    The Sutong Yangtze River Bridge (short as Sutong Bridge) is now the largest span cable-stayed bridge in the world. The construction of the superstructure of the middle bridge covered several stages including erection of the big block girders for the side span, assistant span and tower area, erection of standard girders and closure of the middle span. The big block girders were hoisted by a floating crane, and the standard girders were hoisted by a double crane system on the deck. The pushing assistant method was adopted for the middle span closure construction. Furthermore, key technologies and innovative methods used in the processes of girder erection and cable assemblage in all stages were expatiated systematically. An all-stage self- adaptive geometry control method was used in the construction process. By accurately controlling the unstressed dimensions and shape of all structural components in each step, and realization that the control system and the controlled system adapt to each other, the goal was to make control of the final line shape and inner force of the bridge structure achievable. Two solutions, including GPS based and total station based dynamic geometry monitoring systems, were used to resolve the measure problem under the wide-range of wind-induced vibrations in the long cantilever state. Finally, research on the wind-induced vibration of the superstructure during the construction period was executed. Buffeting response analysis to the longest single and double cantilever states were carried out. The analysis and evaluation of wind resistance safety of the main girders under the longest single cantilever state was made, and corresponding wind resistance measures were suggested. The as-built geometric error and cable force error were controlled in a required design range, and this whole technological achievement can be a benchmark for construction of other large span cable-stayed bridges in the future.

  13. Solid Modeling and Finite Element Analysis of an Overhead Crane Bridge

    Directory of Open Access Journals (Sweden)

    C. Alkin

    2005-01-01

    Full Text Available The design of an overhead crane bridge with a double box girder has been investigated and a case study of a crane with 35 ton capacity and 13 m span length has been conducted. In the initial phase of the case study, conventional design calculations proposed by F. E. M. Rules and DIN standards were performed to verify the stress and deflection levels. The crane design was modeled using both solids and surfaces. Finite element meshes with 4-node tetrahedral and 4-node quadrilateral shell elements were generated from the solid and shell models, respectively. After a comparison of the finite element analyses, the conventional calculations and performance of the existing crane, the analysis with quadratic shell elements was found to give the most realistic results. As a result of this study, a design optimization method for an overhead crane is proposed. 

  14. CONTRIBUTION FROM DEICING SALT TO CHEMICAL COMPOSITION OF SALT SUPPLYED TO AREA UNDER THE BRIDGES

    Science.gov (United States)

    Takebe, Masamichi; Ohya, Makoto; Hirose, Nozomu; Ochibe, Keishi; Aso, Toshihiko

    Salt is known to accelerate the corrosion of weathering steel bridges. The origin of salt around girders is valuable information in terms of the maintenance for anti-corrosion of steel bridges. Salt around girders generally originates from sea-salt and deicing salt. Since salt of both origin increases in winter, contribution of deicing salt is hard to be estimated only from fluctuation of total abundance of salt around the bridge. In this study, abundance of Mg2+ as well as that of Cl- in salt sampled under bridges is analyzed. As a result, this study revealed that the supply of deicing salt declines Mg2+/Cl- ratio of salt on the girder. In addition, examination of Mg2+/Cl- ratio of salt sampled under the examined bridge near sea revealed that the fluctuation of quantity of air-born salt under the bridge is ascribed to the fluctuation of supply of sea salt.

  15. Damage Detection for Long-Span Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhao Ling; Li Aiqun; Miao Changqing; Wang Yonglan

    2006-01-01

    Based on the updated finite-element model of a cable-stayed bridge, this study investigates the technique of identifying damage existing in cable or girder by means of numerical simulation. The modal analysis is performed to identify the changes in modal frequencies and curvatures caused by damage, and the static analysis is executed to detect the influence of damage on cable force. The results indicate a relatively significant decrease in frequencies of lower vertical bending modes due to the damage in cable and little change of frequencies due to damage in girder. Different sensitivities to the location of damaged cable are observed from the frequency changes of different bending modes, which can be used to initially locate the damaged cable. The damage in either cable or girder can be further localized by the most significant change in curvature of girder. The damage occurred in a cable produces a remarkable change in force of nearby cables, whereas the damage in girder brings little change of cable forces. In addition, a pragmatic approach for localizing the damage in girder or cable is proposed based on a comprehensive utilization of the changes in frequency of vertical bending modes, modal curvature of girder, and force in cables.

  16. Overall Design and Study of South and North Bridges of Xiazhang Sea-Crossing Bridge%厦漳跨海大桥南、北汊桥总体设计与研究

    Institute of Scientific and Technical Information of China (English)

    王福敏; 罗强; 李军

    2013-01-01

    厦漳跨海大桥主要由北汊桥、海门岛立交及收费服务区、南汊桥、海平立交四大部分组成,全长9.333 km.为适应复杂的自然与建设条件,对该桥桥位方案进行比选,并对项目中关键控制性工程(北汊主桥、南汊主桥)的桥型方案进行研究.经研究,最终确定北汊主桥采用主跨780m的五跨连续钢箱梁斜拉桥方案,南汊主桥采用主跨300 m的结合梁斜拉桥方案.针对项目中复杂的地质条件、高地震烈度和恶劣的风环境,分别采取设置适应性强的桩基础,对较差的桩基地质注浆;按抗震要求进行构造设计,在主桥塔梁处设置纵向阻尼器,引桥设置减隔震支座;北汊主桥采用一种翼型扶手栏杆、南汊主桥采用分流板抗风等措施进行处理.%The Xiazhang Sea-Crossing Bridge,totally 9.333 km long,is composed of four major parts of the north bridge,Haimen Island interchange and toll service area,south bridge and Haiping interchange.To accommodate the complicated natural and construction conditions of the bridge,the bridge site schemes were compared and the bridge type schemes for the critical control projects (the north and south main bridges) were studied.According to the study,it was finally determined that the 5-span continuous steel box girder cable-stayed bridge with a main span 780 m would be adopted for the north main bridge and the composite girder cable-stayed bridge with a main span 300 m would be adopted for the south main bridge.In consideration of the complicated geologic conditions,high intensity earthquake and harsh wind environment,the well adaptive pile foundations were respectively utilized.For the pile foundations at the locations with poor geology,the foundations would be grouted.The structures of the bridge were designed in compliance with the seismic resistance requirements.At the connections between the pylons and girders of the main bridges,the longitudinal dampers were arranged and on the piers

  17. Design of Welded Turnout Bridge on Taiyuan-Zhongwei-Yinchuan Railway%太中银铁路无缝线路道岔桥梁设计

    Institute of Scientific and Technical Information of China (English)

    左家强

    2014-01-01

    太原至中卫至银川铁路文水至靖边段位于吕梁山脉及陕北黄土高原,设计速度200 km/h,铺设跨区间无缝线路有砟轨道。为适应复杂的地形,共有3个车站的4座桥上设置了道岔。桥梁设计时结合具体情况,采用了不同的桥式方案及施工方法。各桥的孔跨布置满足无缝线路道岔的布设原则;对道岔梁采用结构设计软件进行分析,各项指标能满足无缝线路道岔的变形要求。并解决了预应力混凝土箱梁顶板大悬臂剪力滞效应、道岔梁桥墩及基础纵向总刚度与无缝线路道岔受力适应性、桥面及底板变宽连续箱梁支座横向布置等技术难题。经实际运营检验,能保证列车通过时的安全性、舒适性和平稳性。%Wenshui-Jingbian line of Taiyuan-Zhongwei-Yinchuan railway,a ballast jointless track with designed speed of 200 km/h,goes through Luliang Mountains and northern Shanxi Loess Plateau.In order to adapt to the complex terrain, turnouts were installed on four bridges near three stations.Combined with the specific circumstances of each project site, the bridges were designed using different structures and construction methods.The arrangement of spans for each bridge meets the laying principles of welded turnout.MIDAS and BSAS software is employed to ensure analysis for each turnout girder.All indexes met the requirements of the deformation of welded turnout while addressing the shear lag effect on top plate large cantilever of pre-stressed concrete box,adaptability of turnout girder piers and the total longitudinal stiffness of base to welded turnout stress,lateral arrangement of bridge floor and continuous box girders with widened baseboard as well as other technical problems.The actual operation indicates the bridges can ensure a safe,comfortable and smooth running.

  18. Active Control of Long Bridges Using Flaps

    DEFF Research Database (Denmark)

    Hansen, H. I.; Thoft-Christensen, Palle

    The main problem in designing ultra-long span suspension bridges is flutter. A solution to this problem might be to introduce an active flap control system to increase the flutter wind velocity. The investigated flap control system consists of flaps integrated in the bridge girder so each flap...... is the streamlined part of the edge of the girder. Additional aerodynamic derivatives are shown for the flaps and it is shown how methods already developed can be used to estimate the flutter wind velocity for a bridge section with flaps. As an example, the flutter wind velocity is calculated for different flap...... configurations for a bridge section model by using aerodynamic derivatives for a flat plate. The example shows that different flap configurations can either increase or decrease the flutter wind velocity. for optimal flap configurations flutter will not occur....

  19. Overall Design of Baitanhu Lake Bridge%白潭湖大桥总体设计

    Institute of Scientific and Technical Information of China (English)

    张全阳

    2014-01-01

    基于城市桥梁的景观要求,白潭湖大桥主桥采用纵向对称布置的(150+150) m混凝土独塔斜拉桥的设计方案。桥塔以拱为形态元素,采用椭圆形拱塔结构;主梁采用预应力混凝土单箱三室斜腹板箱梁,人行道置于斜拉索锚固区外侧;斜拉索采用扇形空间双索面布置,主梁上锚固采用混凝土齿块锚固形式,塔上锚固采用混凝土锚块+隔板的锚固形式;过渡墩采用花瓶形板式墩。桥塔采用爬模施工,桥塔横梁采用分节段浇筑,设置2 m合龙段;主梁采用分节段支架现浇施工,共分13个施工节段。有限元计算结果表明,结构受力满足规范要求。%Given the demands of landscape effect of city bridges ,the design scheme of a (150+150) m concrete single pylon cable-stayed bridge that is symmetrically arranged in the longitudinal direction is chosen for the main bridge of Baitanhu Lake Bridge .The pylon which is basically an arch is designed as an elliptic arched pylon structure .The main girder is the prestressed concrete three-cell single box structure with inclined webs .The sidewalk is arranged along the outer side of the anchorage zone of the stay cables . The stay cables are fanned out in spatial double cable planes ,which are anchored to the main girder via concrete teeth ,but anchored to the pylon with the assistance of concrete blocks and bulkheads .T he transitional piers are vase-shaped plate piers . The pylon is constructed by climbing formwork and the pylon cross beam is cast in segments with a 2 m long closure section .The main girder is cast in segments on scaffoldings and a total of 13 construction segments are made .The results of the finite element calculation indicate that the force conditions of the structure can meet the code requirements .

  20. A Combined Geophysical/Engineering Approach for the Seismic Safety of Long-Span Bridges

    Science.gov (United States)

    Fäcke, Andreas; Stempniewski, Lothar; Richwalski, Sandra M.; Parolai, Stefano; Milkereit, Claus; Wang, Rongjiang; Bormann, Peter; Roth, Frank

    The spatial distribution of the resonance frequency of the sedimentary cover in the Cologne area was estimated by the horizontal-to-vertical spectral ratio method using ambient noise measurements. A comparison with the eigenfrequencies of selected long-span bridges crossing the Rhine river indicated an overlap in frequency and therefore potential damage in the case of an earthquake. Consequently, we conducted a dynamic vulnerability analysis using the finite-element method. In addition to accelerograms from design spectra, ground motion scenarios with sources located on the most proximate fault (Erft fault) were simulated using a numerical hybrid method that takes into account source, path, and site effects. The results indicated that due to the low frequency content of these scenarios, consistently higher responses - compared to the recommended loads in the German seismic code - were obtained at all selected bridges. Usage of both scenarios revealed specific failure mechanisms. While cable supported bridges seem to be secure, grave failure was detected for a box girder bridge.

  1. Embedded Electromechanical Impedance and Strain Sensors for Health Monitoring of a Concrete Bridge

    Directory of Open Access Journals (Sweden)

    Dansheng Wang

    2015-01-01

    Full Text Available Piezoelectric lead zirconate titanate (PZT is one of the piezoelectric smart materials, which has direct and converse piezoelectric effects and can serve as an active electromechanical impedance (EMI sensor. The design and fabrication processes of EMI sensors embedded into concrete structures are presented briefly. Subsequently, finite element modeling and modal analysis of a continuous rigid frame bridge are implemented by using ANSYS and MIDAS and validated by the field test results. Uppermost, a health monitoring technique by employing the embedded EMI and strain sensors is proposed in this paper. The technique is not based on any physical model and is sensitive to incipient structural changes for its high frequency characteristics. A practical study on health monitoring of the continuous rigid frame bridge is implemented based on the EMI and strain signatures. In this study, some EMI and strain sensors are embedded into the box-sectional girders. The electrical admittances of distributed EMI active sensors and the strains of concrete are measured when the bridge is under construction or in operation. Based on the electrical admittance and strain measurements, the health statuses of the continuous rigid frame bridge are monitored and evaluated successfully in the construction and operation stages using a root-mean-square deviation (RMSD index.

  2. Design of Non-Navigable Span Bridges of Hutong Changjiang River Bridge%沪通长江大桥非通航孔桥设计

    Institute of Scientific and Technical Information of China (English)

    梅新咏; 侯健; 刘琳杰

    2015-01-01

    沪通长江大桥设计通行4线铁路、6车道高速公路,其非通航孔桥为简支钢桁梁结构 ,桥梁跨度112 m ,全长2 912 m ,其中跨南岸大堤桥梁3跨共336 m、跨北岸大堤桥梁2跨共224 m、跨水中横港沙区段桥梁21跨共2 352 m.非通航孔桥主桁为三片钢主桁结构 ,上层公路桥面由钢纵横梁与混凝土桥面板结合而成 ,下层铁路桥面由下弦各节点处的钢横梁与混凝土槽形梁结合而成.桥墩采用钻孔灌注桩基础 ,墩身采用单箱三室的空心钢筋混凝土结构.%The Hutong Changjiang River Bridge is designed to carry 4-track railways and 6-lane expressways .The non-navigable span bridges of the bridge are the simply-supported steel truss girder structures with span length of 112 m .The bridges are totally 2 912 m long ,of which the part of the bridges to cross the river dyke on the south bank has 3 spans and is 336 m long ,to cross the river dyke on the north bank has 2 spans and is 224 m long and to cross the section of the Henggang Islet in the river has 21 spans and is 2 352 m long .T he main trusses of the bridges are the three steel main truss structures .The upper highway decks are the structures composited by the steel stringers ,steel cross beams and concrete deck slabs while the lower railway decks are the ones composited by the steel cross beams at the panel points at the lower chords and the concrete channel girders .T he foundations for the piers of the bridges are all the bored piles and the pier shafts are the reinforced concrete three-cell single-box hollow structures .

  3. Ultimate strength analysis of long-span cable-stayed bridges; Chodai chachokyo no shukyoku kyodo kaiseki to kyodo ni kansuru ichikosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Xie, X.; Yamaguchi, H. [Saitama Univ., Urawa (Japan)] Nagai, M. [Nagaoka Technical Coll., Niigata (Japan)

    1998-07-21

    Recently, span of cable-stayed bridges has been getting loner and longer, present situation is that cable-stayed bridges with span 600 to 800m class have been built inside and outside the country, and accurate determination of its ultimate strength has been an important problem statistically. However, concrete design method for evaluating load bearing stress of long-span cable-stayed bridge. Particularly of the main beam whose axial stress is dominating, has not been established so far. As for cable-stayed bridge, even for long-span, effect of plasticization of cross section on ultimate strength is severe because there is little effect of geometric nonlinearity and it is thought that accurate evaluation of ultimate strength only by elastic finite potential analysis is difficult. Accordingly, it is necessary to study the behavior by using combined nonlinear analysis considering the nonlinearity of the material in order to evaluate the safety and economy to long-span cable-stayed bridge. In this report, 3 dimensional analysis method was formularized taking into account the combine nonlinearity of multi-box girder and analysis program of ultimate strength behavior of long-span cable-stayed bridge was developed. 19 refs., 17 figs., 2 tabs.

  4. An Optimization Algorithm for the Design of an Irregularly-Shaped Bridge Based on the Orthogonal Test and Analytic Hierarchy Process

    Directory of Open Access Journals (Sweden)

    Hanbing Liu

    2016-11-01

    Full Text Available Irregularly-shaped bridges are usually adopted to connect the main bridge and ramps in urban overpasses, which are under significant flexion-torsion coupling effects and in complicated stress states. In irregular-shaped bridge design, the parameters such as ramp radius, bifurcation diaphragm stiffness, box girder height, and supporting condition could affect structural performance in different manners. In this paper, the influence of various parameters on three indices, including maximum stress, the stress variation coefficient, and the fundamental frequency of torsional vibration, is investigated and analyzed based on orthogonal test method. Through orthogonal analysis, the major influence parameters and corresponding optimal values for these indices are achieved. Combining with the analytic hierarchy process (AHP, the hierarchical structure model of the multi-indices orthogonal test is established and a comprehensive weight analysis method is proposed to reflect the parameter influence on overall mechanical properties of an irregularly-shaped bridge. Influence order and optimal values of parameters for overall mechanical properties are determined based on the weight of factors and levels calculated by the comprehensive weight analysis method. The results indicate that the comprehensive weight analysis method is superior to the overall balance method, which verifies the effectiveness and accuracy of the comprehensive weight analysis in the parameter optimization of the multi-indices orthogonal test for an irregularly-shaped bridge. Optimal parameters obtained in this paper can provide reference and guidance for parameter control in irregularly-shaped bridge design.

  5. Bridges analysis, design, structural health monitoring, and rehabilitation

    CERN Document Server

    Bakht, Baidar

    2015-01-01

    This book offers a valuable guide for practicing bridge engineers and graduate students in structural engineering; its main purpose is to present the latest concepts in bridge engineering in fairly easy-to-follow terms. The book provides details of easy-to-use computer programs for: ·      Analysing slab-on-girder bridges for live load distribution. ·      Analysing slab and other solid bridge components for live load distribution. ·      Analysing and designing concrete deck slab overhangs of girder bridges under vehicular loads. ·      Determining the failure loads of concrete deck slabs of girder bridges under concentrated wheel loads. In addition, the book includes extensive chapters dealing with the design of wood bridges and soil-steel bridges. Further, a unique chapter on structural health monitoring (SHM) will help bridge engineers determine the actual load carrying capacities of bridges, as opposed to their perceived analytical capacities. The chapter addressing structures...

  6. Wind Tunnel Experiments with Active Control of Bridge Section Model

    DEFF Research Database (Denmark)

    Hansen, Henriette I.; Thoft-Christensen, Palle

    the flutter wind velocity for future ultra-long span suspension bridges. The purpose of the wind tunnel experiments is to investigate the principle to use this active flap control system. The bridge section model used in the experiments is therefore not a model of a specific bridge but it is realistic......This paper describes results of wind tunnel experiments with a bridge section model where movable flaps are integrated in the bridge girder so each flap is the streamlined part of the edge of the girder. This active control flap system is patented by COWIconsult and may be used to increase...... compared with a real bridge. Five flap configurations are investigated during the wind tunnel experiments and depending on the actual flap configuration it is possible to decrease or increase the flutter wind velocity for the model....

  7. Design of Concrete Self-Anchored Suspension Bridge of Wusong Bridge in Jilin City%吉林市雾凇大桥混凝土自锚式悬索桥设计

    Institute of Scientific and Technical Information of China (English)

    张伟; 唐贺强; 宁伯伟

    2011-01-01

    The main bridge of the Wusong Bridge in Jilin City is a 5-span continuous concrete self-anchored suspension bridge with span arrangement (35+68+150+68+35) m. A summarized account of the design and calculation of the main bridge is presented herewith. On the bridge, the transverse and vertical bearings and the longitudinal dampers are arranged in between the stiffening girder and towers. The girder is of a concrete 3-cell single box section, the depth of a typical segment of the girder is 2.5 m and towards the anchorage sections at the side spans, the segments of the girder gradually change into a depth of 6.5 m. A tower of the bridge is a concrete portal frame structure that is 54 m in height and the tower columns and the cross beams on the towers are all of rectangular hollow sections. Beneath a tower pier are the pile caps of separation type and each pile cap is supported by 9 nos. of Φ2.0 m bored piles. The main cables are respectively made up of Φ5.1 mm galvanized high strength steel wires and the hanger cables are of Φ7.0 mm low relaxation galvanized high strength parallel steel wires. In the design, the finite element software MIDAS Civil 2006, the nonlinear analysis software BNLAS for suspension bridge and the plane program SCDS are employed to calculate and analyze the bridge. The results of the calculation and analysis indicate that all checking calculation made for the bridge can conform to the relevant requirements in the codes.%吉林市雾凇大桥主桥为(35+68+150+68+35)m五跨连续混凝土自锚式悬索桥,综述该桥主桥设计与计算.该桥塔梁间设置横、竖向支座和纵向阻尼器;加劲梁采用单箱三室混凝土截面,标准段梁高2.5 m,在边跨锚固段渐变至6.5 m;桥塔采用门形框架混凝土结构,高54 m,塔身及横梁均采用矩形空心截面;桥塔墩下部采用分离式承台,单个承台布置9根φ2.0 m钻孔灌注桩;主缆采用φ5.1 mm镀锌高强钢丝,吊索采用φ7.0 mm低松弛镀锌高强

  8. Shear Lag Effect Analysis of Cross-prestressed Concrete Simply-supported Box Beam%横张预应力混凝土简支箱型梁剪力滞效应分析

    Institute of Scientific and Technical Information of China (English)

    马宇光

    2014-01-01

    结合横张预应力简支箱型梁的构造特点,根据能量变分法所推导的对称单箱单室箱梁桥剪力滞效应理论、剪力滞叠加原理及等效荷载法,分析了跨中截面的剪力滞系数。结果表明:横张预应力混凝土简支箱梁中钢束布置形式以及有效预应力是影响恒载与预应力荷载共同作用下简支箱型梁剪力滞效应的重要因素;同时在结构跨径及构造形式一定的情况下,剪力滞系数与预应力布置形状及恒载作用存在一定的规律性。%Combining with the construction features of cross-prestressed simply-supported box beam ,the shear lag coeffi-cient of mid-span section is analyzed based on the shear lag effect theory and shear lag superposition principle derived from the existing energy variation method of symmetrical single cell box girder bridge as well as the equivalent load method .The results show that the steel beam arrangement and effective prestress of cross-prestressed concrete simply-sup-ported box girder are the important factors to affect the shear lag effect of the simply-supported box beam under the joint action of dead load and prestressed load ;when the structural span and constructed form are constant ,there is a certain regularity between the shear lag coefficient and prestress layout shape form as well as the dead load .

  9. Effect of concrete creep on pre-camber of continuous rigid-frame bridge

    Institute of Scientific and Technical Information of China (English)

    贺国京; 李媛媛; 邹中权; 段靓靓

    2008-01-01

    The effect of concrete creep on the pre-camber of a long-span pre-stressed concrete continuous rigid-frame bridge constructed by cantilever casting method was investigated.The difference of creep coefficients calculated with two Chinese codes was discussed.Based on the calculations,the pre-camber of a pre-stressed concrete continuous rigid-frame box bridge was computed for construction control purpose.The results show that the short-term creep coefficient and long-term creep coefficient calculated with the CC-1985 are larger than those calculated with the CC-2004,while the medium-term creep coefficient calculated with the CC-1985 is smaller than that calculated with the CC-2004.The difference of creep deformation calculated with these two codes is small,and the influences of concrete creep on the pre-camber for most of the segments are negligible.The deflections and stresses of the box girder measured during the construction stages agree very well with the predictions.

  10. Design of Main Bridge of Xi′nan Bridge in Guigang City,Guangxi%广西贵港西南大桥主桥设计

    Institute of Scientific and Technical Information of China (English)

    李翠霞; 张巨生

    2015-01-01

    广西贵港市西南大桥主桥为(46+88+280+88+46) m双塔双索面预应力混凝土边主梁斜拉桥。主梁采用等高度带悬臂的矩形混凝土边主梁与“工”字形钢横梁相结合的形式,整幅桥面宽36.5m,设双向2.0%横坡。桥塔采用“鱼”状流线弧形框架钢筋混凝土结构,塔柱高102.5 m,采用外侧为“D”形圆弧段的箱形截面。桥塔设上、下横梁,均采用预应力混凝土单箱单室结构。全桥共设136根斜拉索,斜拉索采用φs 15.2 m m镀锌钢绞线索,空间双索面扇形布置。桥塔墩采用分离式基础,上、下游分离式基础中心距34.7 m ,其下各设9根φ2.5 m钻孔桩。承台为正方形钢筋混凝土结构。4号墩顶面设一圆端形塔座。%The main bridge of the Xi′nan Bridge in Guigang City ,Guangxi is a prestressed concrete edge main girders cable‐stayed bridge with double pylons ,double cable planes and with span arrangement (46+88+280+88+46) m .T he main girders of the bridge are of the structural type combining the rectangular concrete edge main girders having constant depth and cantilevers with the I‐shape steel cross beams .The width of the whole bridge deck is 36 .5 m and the deck is provided with dual 2 .0% transverse slopes .A pylon of the bridge is the“fish”‐shape streamlined arc frame reinforced concrete structure that is 102 .5 m in height and the outer side of the pylon is of the“D”‐shape round arc box section .The upper and lower cross beams of the pylon are all the prestressed concrete single‐cell single‐box structures .There are totally 136 stay cables arranged for the whole bridge .The stay cables are the φs 15 .2 mm galvanized steel wire strand cables and are arranged in fan shape and spatial double cable planes .The pylon pier is supported on the sep‐arated foundations .T he center‐to‐center distance of the foundations on the upstream and dow n‐stream sides is 34 .7

  11. Evaluation of an existing bridge`s modal properties using simplified finite element analysis

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, C.R.; Duffey, T.A.

    1996-02-01

    The purpose of this paper is to present results of a simplified approach to the dynamic finite element modeling of composite girder-slab bridges using a single beam element to represent the girder-slab cross section. Dynamic properties calculated with these simplified models are compared to experimental results and results obtained from more detailed shell element models. The method for modeling flexural behavior is first discussed followed by a discussion of modeling torsional behavior. The beam element models accurately calculated the mode shapes of the structure, but the associated resonant frequencies showed some error.

  12. Design of Danyang Road Bridge in Heze City%菏泽市丹阳路大桥设计

    Institute of Scientific and Technical Information of China (English)

    张伟

    2015-01-01

    菏泽市丹阳路大桥为(40+100+240+100+40) m 双塔中央单索面半飘浮体系混凝土斜拉桥。该桥塔、墩固结,主梁与塔、墩间设置横、竖向支座和纵向液压阻尼器;主梁采用单箱三室斜腹板截面,高3.6m。桥塔采用顺桥向人字形的独柱混凝土塔,高68.2m,单箱单室矩形空心截面。人字形塔柱穿过主梁,与墩身顺接,墩身采用十字形空心薄壁截面,矩形承台,布置33根φ2.0m钻孔灌注桩。辅助墩和交接墩均采用花瓶形双柱式框架墩,矩形承台,布置8根φ1.5m钻孔灌注桩。斜拉索采用φ7 mm镀锌高强平行钢丝束。采用MIDAS Civil 2006和SCDS平面程序对该桥进行计算分析,结果表明该桥各项检算均满足规范要求。%T he Danyang Road Bridge in Heze City is a semi‐floating system concrete cable‐stayed bridge with double pylons ,a central single cable plane and with span arrangement (40+100+240+100+40) m .T he pylons and piers of the bridge are rigidly fixed and in betw een the main girder and pylons and piers ,the lateral and vertical bearings and the longitudinal hydraulic damp‐ers are arranged .The cross section of the main girder is the section of triple‐cell single box with in‐clined webs and the girder is 3 .6 m in depth .In the longitudinal direction of the bridge ,a pylon is the single‐column concrete pylon in the shape of inverted Y ,is 68 .2 m in height and the cross sec‐tion of the pylon is the rectangular hollow section of single‐cell single box .The inverted Y‐shape pylon passes through the main girder and is smoothly fixed with the pylon pier .The cross section of the pylon pier is the crisscross hollow thin‐wall section and the pier stands on the rectangular pile cap under w hich 33 nos .of φ2 .0 m bored piles are arranged .T he auxiliary piers and boundary piers are all the vase‐shape double‐column frame piers and respectively stand on each rectangular

  13. A Cyber-Physical System for Girder Hoisting Monitoring Based on Smartphones

    Science.gov (United States)

    Han, Ruicong; Zhao, Xuefeng; Yu, Yan; Guan, Quanhua; Hu, Weitong; Li, Mingchu

    2016-01-01

    Offshore design and construction is much more difficult than land-based design and construction, particularly due to hoisting operations. Real-time monitoring of the orientation and movement of a hoisted structure is thus required for operators’ safety. In recent years, rapid development of the smart-phone commercial market has offered the possibility that everyone can carry a mini personal computer that is integrated with sensors, an operating system and communication system that can act as an effective aid for cyber-physical systems (CPS) research. In this paper, a CPS for hoisting monitoring using smartphones was proposed, including a phone collector, a controller and a server. This system uses smartphones equipped with internal sensors to obtain girder movement information, which will be uploaded to a server, then returned to controller users. An alarming system will be provided on the controller phone once the returned data exceeds a threshold. The proposed monitoring system is used to monitor the movement and orientation of a girder during hoisting on a cross-sea bridge in real time. The results show the convenience and feasibility of the proposed system. PMID:27399710

  14. A Cyber-Physical System for Girder Hoisting Monitoring Based on Smartphones.

    Science.gov (United States)

    Han, Ruicong; Zhao, Xuefeng; Yu, Yan; Guan, Quanhua; Hu, Weitong; Li, Mingchu

    2016-07-07

    Offshore design and construction is much more difficult than land-based design and construction, particularly due to hoisting operations. Real-time monitoring of the orientation and movement of a hoisted structure is thus required for operators' safety. In recent years, rapid development of the smart-phone commercial market has offered the possibility that everyone can carry a mini personal computer that is integrated with sensors, an operating system and communication system that can act as an effective aid for cyber-physical systems (CPS) research. In this paper, a CPS for hoisting monitoring using smartphones was proposed, including a phone collector, a controller and a server. This system uses smartphones equipped with internal sensors to obtain girder movement information, which will be uploaded to a server, then returned to controller users. An alarming system will be provided on the controller phone once the returned data exceeds a threshold. The proposed monitoring system is used to monitor the movement and orientation of a girder during hoisting on a cross-sea bridge in real time. The results show the convenience and feasibility of the proposed system.

  15. 重庆寸滩长江大桥主桥设计%Design of Main Bridge of Cuntan Changjiang River Bridge in Chongqing

    Institute of Scientific and Technical Information of China (English)

    唐贺强; 曹洪武; 万田保

    2013-01-01

    The main bridge of Cuntan Changjiang River Bridge in Chongqing is a single-span simply-supported steel box girder suspension bridge with span arrangement 250 m+880 m+250 m.The bridge has two main cables that are the structures of prefabricated parallel high-strength steel wire strands.There are totally 57 pairs of the suspenders arranged for the whole bridge,the suspenders are the structures of prefabricated parallel steel wire strands and are connected with the cable bands by way of pin connection.The tower saddles are the fully cast structures and under a tower saddle,the base plate is arranged and is used as the sliding set.The splay saddles are the base structures and under a splay saddle,the cylindrical steel bearing is arranged.The anchoring systems for the main cables are the shaped steel anchoring systems.The stiffening girder of the bridge is designed as the streamlined flat closed steel box girder that is 3.5 m deep and 42 m wide.The anchorage on both the south and north banks are the gravity anchorage,the foundation for each anchorage is the cast-in-situ enlarged foundation and the body of the anchorage is in U shape in plan.The towers are the reinforced concrete portal frame structures.The two columns of a tower are arranged vertically and the foundation of the tower is the pile foundation with separated pile caps.%重庆寸滩长江大桥主桥为250m+880m+250m的单跨简支钢箱梁悬索桥.该桥设2根主缆,主缆采用预制平行高强钢丝索股结构.全桥共布置57对吊索,吊索采用预制平行钢丝束,与索夹采用销接式连接方式.主索鞍为全铸式结构,鞍底设置座板作为滑动副.散索鞍为底座式结构,底部设置柱面钢支座.主缆锚固系统采用型钢锚固系统.加劲梁采用流线型扁平式封闭钢箱梁,梁高3.5m,宽42 m.南、北锚碇均为重力式锚碇,现浇扩大基础,锚体在平面均呈U形.桥塔为钢筋混凝土门式框架结构,两塔柱竖直布置,基础为分离式承台桩基础.

  16. Analysis and assessment of bridge health monitoring mass data—progress in research/development of "Structural Health Monitoring"

    Institute of Scientific and Technical Information of China (English)

    LI AiQun; DING YouLiang; WANG Hao; GUO Tong

    2012-01-01

    The "Structural Health Monitoring" is a project supported by National Natural Science Foundation for Distinguished Young Scholars of China (Grant No.50725828).To meet the urgent requirements of analysis and assessment of mass monitoring data of bridge environmental actions and structural responses,the monitoring of environmental actions and action effect modeling methods,dynamic performance monitoring and early warning methods,condition assessment and operation maintenance methods of key members are systematically studied in close combination with structural characteristics of long-span cable-stayed bridges and suspension bridges.The paper reports the progress of the project as follows.(1) The environmental action modeling methods of long-span bridges are established based on monitoring data of temperature,sustained wind and typhoon.The action effect modeling methods are further developed in combination with the multi-scale baseline finite element modeling method for long-span bridges.(2) The identification methods of global dynamic characteristics and internal forces of cables and hangers for long-span cable-stayed bridges and suspension bridges are proposed using the vibration monitoring data,on the basis of which the condition monitoring and early warning methods of bridges are developed using the environmental-condition-normalization technique.(3) The analysis methods for fatigue loading effect of welded details of steel box girder,temperature and traffic loading effect of expansion joint are presented based on long-term monitoring data of strain and beam-end displacement,on the basis of which the service performance assessment and remaining life prediction methods are developed.

  17. Damage alarming of long-span suspension bridge based on GPS-RTK monitoring

    Institute of Scientific and Technical Information of China (English)

    缪长青; 王蔓; 田洪金; 冯兆祥; 陈策

    2015-01-01

    Structure damage identification and alarming of long-span bridge were conducted with three-dimensional dynamic displacement data collected by GPS subsystem of health monitoring system on Runyang Suspension Bridge. First, the effects of temperature on the main girder spatial position coordinates were analyzed from the transverse, longitudinal and vertical directions of bridge, and the correlation regression models were built between temperature and the position coordinates of main girder in the longitudinal and vertical directions; then the alarming indices of coordinate residuals were conducted, and the mean-value control chart was applied to making statistical pattern identification for abnormal changes of girder dynamic coordinates; and finally, the structural damage alarming method of main girder was established. Analysis results show that temperature has remarkable correlation with position coordinates in the longitudinal and vertical directions of bridge, and has weak correlation with the transverse coordinates. The 3% abnormal change of the longitudinal coordinates and 5% abnormal change of the vertical ones caused by structural damage are respectively identified by the mean-value control chart method based on GPS dynamic monitoring data and hence the structural abnormalities state identification and damage alarming for main girder of long-span suspension bridge can be realized in multiple directions.

  18. Virtual box

    DEFF Research Database (Denmark)

    Stougaard, Malthe Kirkhoff

    2007-01-01

    . This paper reports on the design, implementation and initial evaluation of Virtual Box. Virtual Box attempts to create a physical and engaging context in order to support reciprocal interactions with expressive content. An implemented version of Virtual Box is evaluated in a location-aware environment...

  19. 三跨变截面预应力混凝土双箱双室并联连续箱梁桥的空间受力分析研究%Spatial Analysis of Three-span Prestressed Concrete Continuous Box Girder Bridge with Tow Parallel Boxes Double Celles and Varying Depth

    Institute of Scientific and Technical Information of China (English)

    陈菁菁; 姚永丁; 陶舍辉; 项贻强

    2003-01-01

    本文对一座典型的三跨(30+50+30)变截面预应力混凝土双箱双室并联连续箱梁桥,利用空间板壳有限元来模拟真实的桥梁,进行空间受力分析和参数研究,并进行了荷载试验研究,说明宽桥横向刚度对桥梁变形和应力的影响.

  20. Fasting style collapse of a multi-span arch bridge analyze the causes of the box%某多跨空腹式箱形拱桥倒塌成因分析

    Institute of Scientific and Technical Information of China (English)

    饶奇志; 易汉斌; 俞博

    2014-01-01

    In this paper, a box-shaped multi-span arch bridge collapsed fasting accident, for example, ana-lyze the causes of its collapse. First, the bridge collapse accident scene investigation, proved a bit of geologi-cal bridge pier foundation and Conditions; secondly, according to the findings of the arch structure was seized count;moreover, considering the effect of cutting down on the pile bearing capacity of the river bed;the results show that under the riverbed leads to the bridge substructure cut transition from low pile platform for high pile caps, this time the stakes withstand compressive stress is greater than its carrying capacity, the stakes can not bear the weight of the upper structure, leading to the occurrence of arch collapsed.%本文以某多跨空腹式箱形拱桥倒塌事故为例,对其倒塌成因进行了分析。首先,对桥梁倒塌事故现场进行了调查,探明了桥墩基础及桥位地质条件情况;其次,根据调查结果对拱桥结构进行了检算;此外,考虑了河床下切对桩基承载力的影响;分析结果表明,河床下切导致该桥下部结构从低桩承台转变为高桩承台,此时木桩承受的压应力大于其承载能力,木桩已经不能承担上部结构自重的作用,导致拱桥发生倒塌。

  1. Wave induced extreme hull girder loads on containerships

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Pedersen, Preben Terndrup; Shi, Bill;

    2009-01-01

    , forward speed and hull flexibility. The vertical hull girder loads are evaluated for specific operational profiles. Firstly a quadratic strip theory is presented which can give separate predictions for the hogging and sagging bending moments and shear forces and for hull girder loads. Then this procedure...... is used as a base to derive semi-analytical formulas such that approximate wave load calculations can be performed by a simple spreadsheet program. Due to the few input parameters this procedure can be used to estimate the wave-induced bending moments at the conceptual design phase. Since the procedure...

  2. Construction Scheme of EPC Mode Proposed for Main Bridge of Chacao Bridge in Chile%智利查考大桥EPC投标主桥施工方案

    Institute of Scientific and Technical Information of China (English)

    赵有明; 樊挺; 葛国库; 金仓

    2014-01-01

    查考大桥(Puente Chacao )位于智利南部,连接智利本土和奇洛埃岛,由智利公共工程部面向国际招标,采用 EPC模式建设。中国一家联合体提交的投标方案为(216+1045+1190+319) m的三塔两跨连续钢箱梁悬索桥。为了满足招标文件对工程功能及施工工期的要求,对各重要的施工分项经过方案比选后确定:桥塔均采用混凝土塔,塔柱采用液压爬模分节段现浇;南塔和中塔桥塔基础采用扩大基础,北塔采用钻孔灌注桩基础,南、北锚碇均采用重力式锚碇,基坑采用分台阶明挖;加劲梁采用钢箱梁,在国内加工完成后节段整体海运至桥位,采用跨缆吊机吊装架设;主桥设2根主缆,采用PPWS法架设。%Chacao bridge is located in the south of Chile ,linking the mainland and Chiloe Is-land .The tender conducted by Chile′s Department of Public Works is for companies worldwide , and the project will adopt EPC mode . A consortium from China proposed a scheme of (216 +1 045+1 190+319)m three-tower two-span continuous steel box girder suspension bridge .To ac-commodate functions of the project and the construction schedule prescribed in the tender docu-ments ,the solutions for each key construction items were determined through scheme comparison and selection .All the towers are concrete towers ,the columns of which are cast in situ in sections by hydraulic climbing formwork .Spread foundations are chosen for the south and intermediate towers ,and the bored pile foundation for the north tower .The south and north anchor blocks are of gravity type ,foundation pits of which are to be excavated in steps .The stiffening girder adopts steel box girder ,w hich is to be fabricated in China in segments before being shipped to the bridge site .The girder sections will be erected by cable cranes .The main bridge has two main cables which are erected by parallel wire strand method .

  3. Geometric Nonlinear Analysis of Self-Anchored Cable-Stayed Suspension Bridges

    Directory of Open Access Journals (Sweden)

    Wang Hui-Li

    2013-01-01

    Full Text Available Geometric nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. The repercussion of shrinkage and creep of concrete, rise-to-span ratio, and girder camber on the system is discussed. A self-anchored cable-stayed suspension bridge with a main span of 800 m is analyzed with linear theory, second-order theory, and nonlinear theory, respectively. In the condition of various rise-to-span ratios and girder cambers, the moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800 m, and the error is less than 6%. The shrinkage and creep of concrete impose a conspicuous impact on the structure. And it outmatches suspension bridges for system stiffness. As the rise-to-span ratio increases, the axial forces of the main cable and the girder decline. The system stiffness rises with the girder camber being employed.

  4. 混凝土桥梁事故成因分析及加固策略%Causes of concrete bridge accidents and bridge reinforcement strategies

    Institute of Scientific and Technical Information of China (English)

    陈军军

    2014-01-01

    通过回顾过去几年发生的一些影响较大的钢筋混凝土梁桥事故,分析了这些事故的原因,最后阐述了对钢筋混凝土梁桥进行加固所常用的一些方法。%By reviewing some of the reinforced concrete girder bridge accidents which have significant impact in the past few years, analyzes the causes of these accidents , and finally expounds the reinforcement of reinforced concrete girder bridge with the commonly used methods .

  5. 某钢箱人行天桥动力特性及广告牌加设方案分析%The Dynamic Characteristics of a Steel - box Pedestrian Bridge and Program Analysis of Pedestrian Bridge Installed with Billboard

    Institute of Scientific and Technical Information of China (English)

    杨洋; 丁瑞瑞

    2015-01-01

    As a result of own merit of high strength and light weight, the steel structure, matched the development of cities, obtained the widespread application in recent ten years. However, the pedestrian bridges' burthen has been gradually in-creasing because of rapid development of urban construction and steady expanding of population, together with people's aesthetic requirements, therefore, it is urgent to analyse the reliability of the existing steel pedestrian bridges. In view of the existing situ-ation, with the pedestrian bridge of jinxin plaza in FuGu county, Shaanxi, for example, to ensure the safety of installing bill-boards on the pedestrian bridge, a site loading test has been done, and briefly analyse the static and dynamic characteristics of the pedestrian bridge. Through the analysis of the natural fre-quencies and the displacement time history of the pedestrian bridge, pointed out the existing problems about the billboard on the bridge, and proposed corresponding measures about reinfor-cing and reforming the billboards. It can serve as references for the design, construction and maintenance of the similar pedestri-an bridge structure.%由于钢结构强度高、自重轻的优点,并且能适应城市的发展需要,在近十多年来得到了很大应用。然而,随着城市建设的大力发展和人口的日益增长,加之人们对美学的要求,钢结构人行天桥的负荷程度日益增加,因此,对现有钢结构人行天桥进行可靠性分析是十分重要的。本文针对这一现状,以陕西省府谷县金信广场人行天桥为例,为使该人行天桥安全的加装广告牌,对其进行了现场荷载试验,简要分析了人行天桥静力,动力特性,通过分析该人行天桥的自振频率和位移时程,指出了广告牌在该桥中存在的问题,并提出了相应广告牌加固改造措施,可为类似结构的人行天桥设计、施工及维修养护提供参考。

  6. A Damage Prognosis Method of Girder Structures Based on Wavelet Neural Networks

    Directory of Open Access Journals (Sweden)

    Rumian Zhong

    2014-01-01

    Full Text Available Based on the basic theory of wavelet neural networks and finite element model updating method, a basic framework of damage prognosis method is proposed in this paper. Firstly, a damaged I-steel beam model testing is used to verify the feasibility and effectiveness of the proposed damage prognosis method. The results show that the predicted results of the damage prognosis method and the measured results are very well consistent, and the maximum error is less than 5%. Furthermore, Xinyihe Bridge in the Beijing-Shanghai Highway is selected as the engineering background, and the damage prognosis is conducted based on the data from the structural health monitoring system. The results show that the traffic volume will increase and seasonal differences will decrease in the next year and a half. The displacement has a slight increase and seasonal characters in the critical section of mid span, but the strain will increase distinctly. The analysis results indicate that the proposed method can be applied to the damage prognosis of girder bridge structures and has the potential for the bridge health monitoring and safety prognosis.

  7. Construction of the world's first continuous PC steel composite extradosed bridge. New Meishin Expressway Kiso River Bridge and Ibi River Bridge; Sekaihatsu no PC {center_dot} ko fukugo renzoku ekusutora dozudo kyo no seko. Dai 2 meishin kosoku doro Kisogawa kyo {center_dot} Ibigawa kyo

    Energy Technology Data Exchange (ETDEWEB)

    Mizuguchi, Kazuyuki; Nakasu, Makoto [Japan Highway Public Corpration, Tokyo (Japan)

    1999-09-10

    Kiso River Bridge and Ibi River bridge in the Second Meishin Expressway are the bridges lying across the river mouths of Kiso River and Ibi River which are two of the biggest rivers in Japan. Since a span length of 160m or more is necessary when constructing the bridges, comparison examinations in respect to bridge forms that can secure a long span were carried out. As a result, the world's first continuous PC steel composite extradosed bridge was adopted. The construction works of these two bridges were each divided into the east and the west works, thus totally four constructions works were ordered. Now both the two bridges are approaching the most active period of their superstructure works. In this paper, summary of the superstructure works of these two bridges is described and the situation of concrete girder portions operated hitherto is introduced. Particularly, for the concrete girder portions in composite structures, an extrodosed form is employed to arrange PC members outside the girders so as to use them more effectively and make prestress force act on a main girder at a great eccentricity. (NEDO)

  8. Research on vibration control of steel structural pedestrian bridge from pedestrian excitation%钢结构过街天桥人行激励振动控制研究

    Institute of Scientific and Technical Information of China (English)

    魏达; 贾杰; 褚若帆; 孔高强; 张义卓

    2015-01-01

    以钢结构箱形梁过街天桥为例,通过实测数据建立人行荷载模拟,分析行人的舒适度指标,采取阻尼片振动控制措施并分析了减振效果,对今后的过街天桥建设有参考借鉴意义。%Based on the steel box girder pedestrian,the people’s load simulation is established through the measured data,comfortable index is analyzed in this paper. Simultaneously,vibration control measures of the damping is presented and vibration effect is analyzed. These will be the basis of the future construction of the pedestrian bridges.

  9. Parametric study on responses of a self-anchored suspension bridge to sudden breakage of a hanger.

    Science.gov (United States)

    Qiu, Wenliang; Jiang, Meng; Huang, Cailiang

    2014-01-01

    The girder of self-anchored suspension bridge is subjected to large compression force applied by main cables. So, serious damage of the girder due to breakage of hangers may cause the collapse of the whole bridge. With the time increasing, the hangers may break suddenly for their resistance capacities decrease due to corrosion. Using nonlinear static and dynamic analysis methods and adopting 3D finite element model, the responses of an actual self-anchored suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of a hanger causes violent vibration and large changes in internal forces of the bridge. In the process of the vibration, the maximum tension of hanger produced by breakage of a hanger exceeds 2.22 times its initial value, and the reaction forces of the bearings increase by more than 1.86 times the tension of the broken hanger. Based on the actual bridge, the influences of some factors including flexural stiffness of girder, torsion stiffness of girder, flexural stiffness of main cable, weight of girder, weight of main cable, span to sag ratio of main cable, distance of hangers, span length, and breakage time of hanger on the dynamic responses are studied in detail, and the influencing extent of the factors is presented.

  10. Parametric Study on Responses of a Self-Anchored Suspension Bridge to Sudden Breakage of a Hanger

    Directory of Open Access Journals (Sweden)

    Wenliang Qiu

    2014-01-01

    Full Text Available The girder of self-anchored suspension bridge is subjected to large compression force applied by main cables. So, serious damage of the girder due to breakage of hangers may cause the collapse of the whole bridge. With the time increasing, the hangers may break suddenly for their resistance capacities decrease due to corrosion. Using nonlinear static and dynamic analysis methods and adopting 3D finite element model, the responses of an actual self-anchored suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of a hanger causes violent vibration and large changes in internal forces of the bridge. In the process of the vibration, the maximum tension of hanger produced by breakage of a hanger exceeds 2.22 times its initial value, and the reaction forces of the bearings increase by more than 1.86 times the tension of the broken hanger. Based on the actual bridge, the influences of some factors including flexural stiffness of girder, torsion stiffness of girder, flexural stiffness of main cable, weight of girder, weight of main cable, span to sag ratio of main cable, distance of hangers, span length, and breakage time of hanger on the dynamic responses are studied in detail, and the influencing extent of the factors is presented.

  11. Vibration analysis of the Second Saikai Bridge—a concrete filled tubular (CFT) arch bridge

    Science.gov (United States)

    Yoshimura, Mistuhiro; Wu, Qingxiong; Takahashi, Kazuo; Nakamura, Shozo; Furukawa, Kazuyoshi

    2006-02-01

    Concrete-filled steel tubular (CFT) arch bridges have been rapidly developing in China since 1990. Research has focused on the static behavior, thermal stress and erection technique, however, and there has been very little research of natural vibrations and dynamic responses of these bridges. Japan's first CFT arch bridge in highway bridges, the Second Saikai Bridge, is now under construction in Nagasaki Prefecture. Furthermore, this bridge has a pedestrian bridge that is suspended under the girder, which is rare. Therefore, the natural vibration properties are examined, and the influence of pedestrian bridge structure on the natural vibration of main bridge is discussed first. Response analysis under a moving vehicle and pedestrian is carried out, and the response characteristics and response level are clarified. The natural vibrations and responses are compared to those of CFT arch bridges that have been constructed in China. Results show the fine performance of both main bridge and pedestrian bridge of the Second Saikai Bridge.

  12. Development of base isolation system for existing bridges; Kisetsu kyoryo no menshinka koho no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Nagumo, H.; Hishiki, T.; Niihara, Y.; Aizawa, J.; Ichinomiya, T. [Kajima Corp., Tokyo (Japan)

    1997-12-20

    The new base-isolation system has been developed for existing bridges, which meets the functional and executional requirements. Described herein are outline of the new system, results of the shaking table tests conducted to confirm its validity, and simulation analysis of the test results. These results confirm that the new system, which uses horizontal force dampers and sliding bearings, is suited for existing bridges. Its basic characteristics are also described. The new system exhibits a sufficient base isolation effect, because the observed acceleration of the girder can be reduced to 1/2 to 1/3 that of a girder supported by the conventional system. It is also confirmed that the relative displacement between the pier and girder during a level 1 earthquake is below 5mm for an RC bridge with a span of 20m or so, a level which does not lead to damage of the bridge joints. The simulation analysis indicates that the new system could reduce the relative displacement between the pier and girder during a level 1 earthquake to 1/5 that associated with the bridge supported by the conventional system, by additional damping effects coming from the horizontal force dampers and sliding bearings. The simulation analysis also indicates that a bridge destroyed by the Great Hanshin Earthquake would have been safe if it had been supported by the new system, which also confirms sufficiently improved resistance to earthquake provided by the new system. 4 refs., 14 figs., 6 tabs.

  13. Limit span of self-anchored cable-stayed suspension cooperation system bridge based on strength

    Institute of Scientific and Technical Information of China (English)

    Zhe ZHANG; Huili WANG; Sifeng QIN; Xiaomeng GE

    2009-01-01

    The limit span of self-anchored cable-stayed suspension bridge is deduced. The relations among the geometrical parameters, loads and material characteristics are also analyzed. Based on the material strength and commonly used materials, the limit spans of self-anchored cable-stayed suspension bridges with concrete girder or steel girder under vertical static load are discussed in detail.The corresponding upper limit spans and the effect of the factors on the span are given. The results indicate that increasing rise-span ratio, height-span ratio and cable-stayed segment length or reducing the second dead load could increase the cooperation system span.

  14. Bento Boxes

    Science.gov (United States)

    Hasio, Cindy

    2010-01-01

    Bento boxes are common objects in Japanese culture, designed to hold enough lunch for one person. They have individual compartments and sometimes multiple tiers for rice, vegetables, and other side dishes. They are made of materials ranging from wood, cloth, aluminum, or plastic. In general, the greater the number of foods, the better the box is…

  15. Random Young diagrams in a Rectangular Box

    DEFF Research Database (Denmark)

    Beltoft, Dan; Boutillier, Cédric; Enriquez, Nathanaël

    We exhibit the limit shape of random Young diagrams having a distribution proportional to the exponential of their area, and confined in a rectangular box. The Ornstein-Uhlenbeck bridge arises from the fluctuations around the limit shape.......We exhibit the limit shape of random Young diagrams having a distribution proportional to the exponential of their area, and confined in a rectangular box. The Ornstein-Uhlenbeck bridge arises from the fluctuations around the limit shape....

  16. 基于实测数据的润扬大桥悬索桥全寿命评估随机温度场模拟%Simulation of stochastic temperature field for Runyang suspension bridge life-cycle evaluation based on monitoring data

    Institute of Scientific and Technical Information of China (English)

    周广东; 李爱群; 丁幼亮; 王高新

    2013-01-01

    A stochastic temperature field simulation method for steel box-girder bridge based on moni-toring data is developed to provide sufficient temperature data for life-cycle evaluation.First, the least square estimation and hypothesis testing are employed to analyze the statistical data of monitoring tem-perature and thermal diffeernce of the flat steel-box girder of the Runyan g suspension bridge ( RSB) in five years.Then, a numerical inverse transform sampling method is proposed to simulate sam ple series with the complex statistical model, and the life-cycle stochastci temperature field of the flat steel-box gir der is simulated.The results show that the monitoring temperature of the falt steel-box girder can be described by the we ighted sum of two normal distributions, while the thermal diference among test points can be presented by the weighted su m of the Weibull distribution and the normal distribution. Teh probability distribution function of the sample simulate d by the numercial i nevr set ransform sam-pling method agrese well with the target probability distribution function.T he simulated temperature field can accurately describe the etmperature field's characteristics of the flat steel box-g irder.There-fore, the numerical inverse rt ansform samlping method can accurately simulate the life-cycle stochas tic temperature field of the flat steel box girder of the long-span suspension bridge.%为了得到桥梁全寿命评估的温度数据,提出了一种基于实测数据的钢箱梁桥随机温度场模拟方法。首先,采用最小二乘估计和假设检验,对润扬大桥悬索桥扁平钢箱梁为期5年的实测温度和温差进行了统计分析;然后,提出了一种复杂统计模式下样本序列模拟的数值逆变换抽样方法,并建立了扁平钢箱梁的全寿命评估随机温度场。研究结果表明:扁平钢箱梁实测温度服从2个正态分布的加权和,实测温差则服从1个Weibull分布和1个正态分

  17. Analysis of Biaxially Stressed Bridge Deck Plates

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Bondum, Tommi Højer

    2012-01-01

    The ultimate state analysis of bridge deck plates at the intersection zone between main girders and transverse beams is complicated by biaxial membrane stresses, which may be in compression or tension in either direction depending on the bridge configuration and the specific location. This paper...... presents a detailed investigation of the ultimate capacity of simply supported plates subjected to biaxial loads. The full interaction domain of combinations of compressive and tensile loads has been investigated including a large number of imperfections. It was found that non-standard imperfection modes...

  18. Onboard monitoring of fatigue damage rates in the hull girder

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Dam; Jensen, Jørgen Juncher; Pedersen, Preben Terndrup;

    2011-01-01

    taking into account whipping stresses. It is conceptually shown how such a method, which integrates onboard estimation of sea states, can be used to deduce decision support with respect to the accumulated fatigue damage in the hull girder.The paper firstly presents a set of measured full-scale wave......Most new advanced ships have extensive data collection systems to be used for continuous monitoring of engine and hull performance, for voyage performance evaluation etc. Such systems could be expanded to include also procedures for stress monitoring and for decision support, where the most...... critical wave-induced ship extreme responses and fatigue damage accumulation can be estimated for hypothetical changes in ship course and speed in the automatically estimated wave environment.The aim of this paper is to outline a calculation procedure for fatigue damage rate prediction in hull girders...

  19. Design on Simply-Supported Box Beam in Pearl River Delta Intercity Rail Transit%珠三角城际轨道交通简支箱梁设计

    Institute of Scientific and Technical Information of China (English)

    侯建军; 邓运清

    2012-01-01

    城际轨道交通是联系城市群间的快速铁路客运专线,主要满足经济发达的人口稠密地区中短途旅客运输需要,对景观设计要求较高.珠三角城际轨道交通桥梁形式采用了流线形箱梁,在箱梁外侧设置大圆弧,小曲线的梁端加宽等处理更加体现了城际轨道交通桥梁中景观设计要素.其常用简支箱梁根据线间距变化,设计分为双线箱梁、单线箱梁和组合箱梁3种形式.从箱梁设计的技术标准、桥面布置、截面选型等方面进行介绍.%In developed and populous areas, the intercity rail transit is the rapid passenger-dedicated line of urban agglomeration in order to meet the needs of passenger traffic within middle distance and short distance, with the higher requirements on landscape. So the box beam bridges with streamline shape were employed in Pearl River Delta Intercity Rail Transit, in which the large arc shape was utilized along the lateral surface of the box beam, and the girder ends on sharp curve were widened to reflect more landscape elements of intercity rail transit bridge design. Moreover, in the design, according to the various distances between the track centers, the usual simply-supported box beam s were divided into three types; the box beam with double tracks, box beam with single track, and the composite box beam. The technical standards, bridge deck arrangement, cross-section selection and other aspects in box beam design are introduced in this paper.

  20. 考虑腹板剪切行为的波形钢腹板梁理论模型%Theory Model of Corrugated Steel Web Girder Considering Web Shear Behavior

    Institute of Scientific and Technical Information of China (English)

    聂建国; 李法雄

    2011-01-01

    为研究波形钢腹板剪切变形对波形钢腹板梁受力行为的影响,引入腹板剪切变形转角函数,将波形钢腹板梁的弯曲行为分解为桁架作用和弯曲作用,建立一个能够考虑波形钢腹板剪切变形的波形钢腹板梁理论模型。推导了端部无约束条件下简支波形钢腹板梁在均布荷载和端部约束条件下简支波形钢腹板梁在跨中集中荷载作用下的解析解,采用有限元方法验证了理论模型和解析解的正确性和适用性。研究结果表明:端部约束条件对主梁变形影响很小;波形钢腹板的剪切变形对主梁变形影响显著,在常见波形钢腹板梁桥尺寸范围内,由腹板剪切变形引起的主梁挠度占总挠度的10%~30%。%In order to study the influence of shear deformation of forcing behavior for corrugated steel web,shear rotation function of calculating shear deformation in the web was introduced,a theory model of corrugated steel web girder was presented.In the model,bending behavior of corrugated steel web girder could be divided into truss action and bending action between upper-flange and sub-flange.Then,analytical solutions for the cases of simply-supported corrugated steel web girder without end restraint sustaining under uniform distribution load and simply-supported corrugated steel web girder with end restraint under sustaining mid-span concentrated load were derived,validity and usability of the analytical solution and the model were well proved by finite element method.Results show that the end constraint conditions have little effect on the deformation of the main girder.However,the shear deformation of corrugated steel web has great impact on the deformation of main girder.In the common size ranges of bridge with corrugated steel web girders,the proportion of main girder deflection caused by shear deformation in the web may reach 10% to 30% of total deflection.

  1. Design and Construction of a 50m Single Span Ultra High Performance Ductile Concrete Composite Road Bridge

    Directory of Open Access Journals (Sweden)

    Voo - Yen Lei

    2012-04-01

    Full Text Available A single span 50m long prestressed road bridge was constructed under Public Works Department in the State of Negeri Sembilan, Malaysia contract recently. The bridge was constructed at a small village, Kampung Linsum, crossing a river, Sungai Linggi. To date, this bridge is the Malaysia first and may also be the world longest composite road bridge which made from ultra-high performance ductile concrete (UHPdC. This paper presents the feature of the UHPdC precast girder; brief in-sight of the manufacturing of the girder; the construction sequence of the bridge; the design method and lastly the environmental impact calculation. The midspan deflections of the bridge at different construction history were compared against the collected field data and it showed that the calculated values generally agree well with the field data.

  2. Aerodynamic stability of cable-stayed bridges under erection

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-jun; SUN Bing-nan; XIANG Hai-fan

    2005-01-01

    In this work, nonlinear multimode aerodynamic analysis of the Jingsha Bridge under erection over the Yangtze River is conducted, and the evolutions of structural dynamic characteristics and the aerodynamic stability with erection are numerically generated. Instead of the simplified method, nonlinear multimode aerodynamic analysis is suggested to predict the aerodynamic stability of cable-stayed bridges under erection. The analysis showed that the aerodynamic stability maximizes at the relatively early stages, and decreases as the erection proceeds. The removal of the temporary piers in side spans and linking of the main girder to the anchor piers have important influence on the dynamic characteristics and aerodynamic stability of cable-stayed bridges under erection.

  3. 郑州市解放路跨线桥主桥设计与施工%Design and Construction of Main Bridge of Jiefang Road Overpass Bridge in Zhengzhou City

    Institute of Scientific and Technical Information of China (English)

    申国朝

    2012-01-01

    The main bridge of the Jiefang Road Overpass Bridge in Zhengzhou City is a cable-stayed bridge with twin pylons, single cable plane and with span arrangement (106 + 248 + 106) m and the bridge employs the structural system of rigid fixity of its pylons and main girder. The main girder of the bridge is of the prestressed concrete triple-cell single box of quasi-triangle section and has a 62 m long variable width portion at the side span on the west side. On both sides of a pylon, 15 pairs of stay cables made up of the low relaxation and high-strength galvanized parallel steel wires are arranged. The pylons are the concrete solid single-column ones of H-shape sections and the main piers are the vase shape hollow reinforced concrete structures supported on the frictional group bored pile foundations. The software Bridge Doctor V3. 03, MIDAS Civil and ANSYS were used to respectively build the plane finite element model for the bridge and the plane link and spatial plate-shell finite element models for the variable width portion. With these models, the global static force of the bridge and the force conditions of the portion were analyzed. In addition, a 1: 4 model for the variable width portion was also designed and made to carry out the model test. The results of the finite element analysis and model test showed that the force conditions of various parts of the bridge could meet the requirements in the codes. The part of the bridge spanning the passenger dedicated railway line on the east side was constructed by the rotation erection while the part of the bridge spanning the freight railway line on the west side was constructed by the covered form traveler.%郑州市解放路跨线桥主桥为双塔单索面斜拉桥,跨径布置为(106+248+106)m,采用塔、梁固结体系.该桥主梁为预应力混凝土单箱三室准三角形截面,西侧边跨设62 m长的变宽段.每个桥塔两侧布置15对斜拉索,斜拉索采用低松弛镀锌高强平行钢丝.桥塔采

  4. Strengthening of steel–concrete composite girders using carbon fibre reinforced polymer (CFRP) plates

    Indian Academy of Sciences (India)

    S M Mosavi; A Sadeghi Nik

    2015-02-01

    Applying composites in order to strengthen and renew the infrastructures has globally been accepted. Traditional methods to strengthen the out-of-standard structures are costly, time consuming and requires a lot of labour. Today, new techniques are hired using light and strong substances which also resist against corrosion, known as Carbon Fibre Reinforced Polymer (CFRP) plates. Regarding the high tensile strength and proper module of elasticity, CFRP plates are considered as a suitable alternative to strengthen girders. The behaviour of steel–concrete composite girders being statically loaded and strengthened by CFRP plates in this study. The CFRP plates used in this study have been stuck, with epoxy adhesive, under the tensile sections of three steel girders. The results accompanied with analytical study of moment–curvature and numerical analysis done with ANSYS, show that CFRP plates with epoxy adhesive increases the ultimate loading capacity of steel–concrete composite girder. Plastic stiffness of the girders was also increased.

  5. Effects of vertical girder realignment in the Argonne APS storage ring.

    Energy Technology Data Exchange (ETDEWEB)

    Lessner, E.

    1999-04-14

    The effects of vertical girder misalignments on the vertical orbit of the Advanced Photon Source (APS) storage ring are studied. Partial sector-realignment is prioritized in terms of the closed-orbit distortions due to misalignments of the corresponding girders in the sectors. A virtual girder-displacement (VGD) method is developed that allows the effects of a girder realignment to be tested prior to physically moving the girder. The method can also be used to anticipate the corrector strengths needed to restore the beam orbit after a realignment. Simulation results are compared to experimental results and found to reproduce the latter quite closely. Predicted corrector strengths are also found to be close to the actual local corrector strengths after a proof-of-principle two-sector realignment was performed.

  6. Influence of central buckle on suspension bridge dynamic characteristics and driving comfort

    Institute of Scientific and Technical Information of China (English)

    王达; 邓扬; 刘扬

    2015-01-01

    The central buckle, which is often used in a suspension bridge, can improve bridges’ performance in the actual operation condition. The influence of the central buckle on natural vibration characteristics and bridge-deck driving comfort of a long-span suspension bridge is studied by using a case study of Siduhe Suspension Bridge in China. Based on the finite element software ANSYS and independently complied program, the influence of the central buckle on the structure force-applied characteristics of a long-span suspension bridge has been explored. The results show that the huge increases of natural frequencies can result in the presence of central buckles because of the increases of bending and torsional rigidities. The central buckle basically makes the stiffening girders and cables within the triangular area covered as a relatively approximate rigid area. Hence, the central buckle can reduce the torsional displacement of the main girder. However, the increases of bending and torsional rigidities have little influence on the impact factor, which is obtained by using vehicle-bridge coupled vibration analysis. This means that the central buckle has little effect on the comfort indices. In addition, it is found that the central buckle can enhance the bridge deck’s driving stability due to the decrease of the torsional displacements of the main girder.

  7. Investigations concerning seismic response control of self-anchored suspension bridge with MR dampers

    Institute of Scientific and Technical Information of China (English)

    Menggang YANG; Zhengqing CHEN; Jianhua HU

    2008-01-01

    To mitigate the seismic response of selfanchored suspension bridges, equations of motion governing the coupled system of bridge- magneto-rheological (MR) dampers subject to seismic excitation are formulated by employing the phenomenological model of MR dampers. A corresponding computer program is developed and employed for studying the seismic response control of a self-anchored suspension bridge with a main span of 350 m. The effect of variable current and number of dampers on seismic response control is investigated. The numerical results indicate the longitudinal displacement of the tower top and bridge girder decrease with the increase in input current and number of MR dampers attached longitudinally at the tower-girder connections, and the internal forces of the tower are effectively attenuated as well. It appears that small electronic current (0.5 A in this study) may sufficiently attenuate the seismic responses for practical engineering applications.

  8. On the Influence of Hull Girder Flexibility on the Wave

    DEFF Research Database (Denmark)

    Seng, Sopheak; Andersen, Ingrid Marie Vincent; Jensen, Jørgen Juncher

    2012-01-01

    Numerical predictions and model test results of the wave induced bending moments in a 9,400 TEU post-Panamax container vessel are presented for two regular wave scenarios. Different numerical procedures have been applied: a linear and non-linear time-domain strip theory and a direct calculation (...... (CFD) solving the Navier-Stokes equations with the free surface captured by a volume-of-fluid (VOF) method. In all procedures the flexibility of the hull girder is modelled as a non-uniform Timoshenko beam. It is observed that the non-linear models agree well with the model tests...

  9. Einstein's Boxes

    CERN Document Server

    Norsen, T

    2005-01-01

    At the 1927 Solvay conference, Einstein presented a thought experiment intended to demonstrate the incompleteness of the quantum mechanical description of reality. In the following years, the thought experiment was picked up and modified by Einstein, de Broglie, and several other commentators into a simple scenario involving the splitting in half of the wave function of a single particle in a box. In this paper we collect together several formulations of this thought experiment from the existing literature; analyze and assess it from the point of view of the Einstein-Bohr debates, the EPR dilemma, and Bell's theorem; and generally lobby for Einstein's Boxes taking its rightful place alongside similar but historically better-known quantum mechanical thought experiments such as EPR and Schroedinger's Cat.

  10. Structural safety monitoring for Nanjing Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    黄方林; 何旭辉; 陈政清; 曾储惠

    2004-01-01

    In order to evaluate objectively and accurately the integrity, safety and operating conditions in real time for the Nanjing Yangtze River Bridge, a large structural safety monitoring system was described. The monitoring system is composed of three parts: sensor system, signal sampling and processing system, and safety monitoring and assessment system. Combining theoretical analysis with measured data analysis, main monitoring contents and layout of measuring points were determined. The vibration response monitoring was significantly investigated. The main contents of safety monitoring on vibration response monitoring are vibration of the main body of the Nanjing Yangtze river bridge, collision avoidance of the bridge piers, vibration of girders on high piers for the bridge approach and earthquake. As a field laboratory, the safety monitorying system also provides information to investigate the unknown and indeterminate problems on bridge structures and specific environment around bridges.

  11. Sectional model test study on vortex-excited resonance of vehicle-bridge system of Shanghai Bridge over Yangtse River

    Institute of Scientific and Technical Information of China (English)

    Li ZHOU; Yaojun GE

    2009-01-01

    It is necessary to study how vehicles influence the vortex-excited resonance of vehicle-bridge systems,because lock-in wind speed is low and vortex-excited resonance is sensitive to any change in the main girder sections. Based on the Shanghai Bridge over the Yangtse River, the vortex-excited resonance of a 1:60 scale sectional model was tested in a TJ-lwind tunnel, with or without vehicles at the attack angle of 0°, + 3 and -3°,respectively. The conversion relationships between the resonant amplitudes of the sectional model and that of the prototype bridge were also established by mode shape correction. The result indicates that: 1) for the bridge with vehicles, the vertical vortex-excited resonance is accom-panied by torsion vibration with the same frequency, and vice versa, 2) the amplitude of vortex-excited resonance of the bridge with vehicles is much larger than that of the bridge without vehicles, and 3) the lock-in wind speed of the vortex-excited resonance becomes smaller due to the disturbance of vehicles. It is obvious that vehicles bring about changes in the aerodynamic shape of the main girder.Therefore, the influence of vehicles on vortex-excited resonance performance of vehicle-bridge systems, in terms of both amplitude and mode, should not be ignored.

  12. Bragg grating fiber optic sensing for bridges and other structures

    Science.gov (United States)

    Measures, Raymond M.; Alavie, A. Tino; Maaskant, Robert; Huang, Shang Yuan; LeBlanc, Michel

    1994-09-01

    We have demonstrated that fiber optic intracore Bragg grating sensors are able to measure the strain relief experienced over an extended period of time by both steel and carbon composite tendons within the concrete deck support girders of a recently constructed two span highway bridge. This is the first bridge in the world to test the prospects of using carbon fiber composite tendons to replace steel tendons. This unique set of measurements was accomplished with an array of 15 Bragg grating fiber optic sensors that were embedded within the precast concrete girders during their construction. We have also demonstrated that these same sensors can measure the change in the internal strain within the girders associated with both static and dynamic loading of the bridge with a truck. We are now studying the ability of Bragg grating fiber optic sensors to measure strong strain gradients and thereby provide a warning of debonding of any Bragg grating sensor from its host structure...one of the most important failure modes for any fiber optic strain sensor.

  13. First application of second-generation steel-free deck slabs for bridge rehabilitation

    Science.gov (United States)

    Eden, Ruth; Klowak, Chad; Mufti, Aftab A.; Tadros, Gamil; Bakht, Baidar; Loewen, Eric

    2004-07-01

    The arching action in concrete deck slabs for girder bridges is utilized fully in steel-free deck slabs. These concrete slabs, requiring no tensile reinforcement, are confined longitudinally by making them composite with the girders, and transversely by external steel straps connecting the top flanges of external girders. Between 1995 and 1999, five steel-free deck slabs without any tensile reinforcement were cast on Canadian bridges. All these slabs developed fairly wide full-depth cracks roughly midway between the girders. While extensive fatigue testing done in the past three years has confirmed that the presence of even wide cracks does not pose any danger to the safety of the structures, wide cracks are generally not acceptable to bridge engineers. The developers of the steel-free deck slabs have now conceded that these slabs should be reinforced with a crack-control mesh of nominal glass fibre reinforced polymer (GFRP) bars. Steel-free deck slabs with crack-control meshes are being referred as the second generation slabs. With the help of testing on full-scale models, it has been found that deck slabs with GFRP bars have the best fatigue resistance and those with steel bars the worst.

  14. Design of Composite Girder with Non-standard Span on Harbin-Dalian Passenger Dedicated Line%哈大铁路客运专线变跨结合梁设计

    Institute of Scientific and Technical Information of China (English)

    孙宗磊

    2012-01-01

    结合哈大客运专线沈大段桥梁非标准跨度的特点,从适用、景观、施工控制等方面介绍哈大客运专线变跨结合梁的设计过程,对结合梁外形选择、结构断面选择、施工方案以及计算方法进行了详细介绍.%In view of the characteristics of the bridge with non-standard span on Shenyang-Dalian section of Harbin-Dalian Passenger Dedicated Line, this paper introduces the design process of the composite girder with non-standard span on Harbin - Dalian Passenger Dedicated Line in terms of applicability,landscape and construction control, and explains in detail the selection of girder profile, structural cross-section, construction scheme and calculation method.

  15. Seismic Behavior of RNC-Isolated Bridges: A Comparative Study under Near-Fault, Long-Period, and Pulse-Like Ground Motions

    Directory of Open Access Journals (Sweden)

    Mohammed Ismail

    2016-01-01

    Full Text Available This paper introduces a recent seismic isolation system, named Roll-in-Cage (RNC isolator, for efficient protection of bridges against destructive earthquakes. The RNC isolator is a rolling-based isolation system with several integrated features in a single unit providing all the necessary functions of vertical rigid support, horizontal flexibility, full stability, hysteretic energy dissipation, and resistance to minor vibration loads. Besides, it is distinguished by a self-stopping (buffer mechanism to limit the peak bearing displacement under abrupt severe excitations, a linear gravity-based self-recentering mechanism to prevent permanent dislocations after excitations, and a notable resistance to axial tension. A three-span box-girder prestressed concrete bridge is investigated under a set of different destructive real and synthetic earthquakes including near-fault, long-period, and pulse-like ground motions. As a performance measure, the responses of isolated and nonisolated cases are compared. In addition, the RNC isolator’s behavior is then compared with those of other isolation systems including HDB, FPS, and LRB. The results confirmed that the RNC isolator has a superior behavior in achieving a balance between the peak displacements and accelerations of the isolated deck, relative other isolation systems, besides being the most (relatively efficient isolator in the great majority of studies performed.

  16. Procurement of Beams in Multiple D&B Bridge Projects

    Directory of Open Access Journals (Sweden)

    CT. Ramanathan

    2010-06-01

    Full Text Available Selected infrastructure development projects are being implemented by Design and Build (D&B pocurement system in Sabah (East Malaysia by the Public Works Department (PWD. In the first phase 45 bridge replacement projects were awarded in 5 packages. These simultaneous multiple Bridge projects are for the development of the backward areas and hence their timely completion is utmost important. Procurement and production of bridge beams have been the critical element of construction in these rural areas and no researches has been reported on various aspects of procurement of the bridge beams in multiple D&B projects. The aspects of procurement researched in this work include the determination of a common beam element for the ease of procurement and the optimization of the construction methodology, the finalization and purchasing plate dimensions to suite the manufacturer's production range, the delivery of materials, the planning and monitoring of fabrication, the preparation and assembly, and the erection and launching of beams. The beams are optimized using element optimization techniques. The most important problems in fabricating steel girders were in planning and scheduling of materials for the fabrication and the fabrication process. Findings in all the aspects of production of steel girders are highlighted through a case study of six long span bridges at various locations in Sabah. Solutions drawn from lessons learnt which minimize wastages, and aids in timely completion of beams in multiple bridge construction are discussed.

  17. Comparison of Technologies for Erection of Bamboo Veneered Formwork for Arc Section of Web Slabs of Box Girders for Bridges%几种箱梁腹板弧形段竹胶板模板施工工艺比较

    Institute of Scientific and Technical Information of China (English)

    王迎松; 朱晓君

    2008-01-01

    针对目前桥梁箱梁腹板弧形段施工中常见的几种施工工艺,进行了综合分析比较,得出采用10 mm竹胶板作为腹板弧形段面板,采用单根钢管制作成钢托横格栅支撑结构的箱梁腹板弧形段竹胶板模板施工工艺作为箱梁弧形段施工的最佳工艺,并期望在桥梁施工中能够普及推广.

  18. Full Space Bowl Shaped Support Scheme Design of Super-Large Bridge's Prestressed Concrete Continuous Box Girder%特大桥预应力混凝土连续箱梁满堂式碗口支架方案设计

    Institute of Scientific and Technical Information of China (English)

    李志明

    2013-01-01

    混凝土连续箱梁施工中,支架为桥梁上部提供了施工平台,同时也是重要的支撑体系,其安全性必须得到充分保证.依据设计图纸和现场实际情况,设计了满堂式碗口支架的方案,并对方案进行了验算.

  19. Quality Control Keys of Construction for Bridge Approach with Cast-in-place Prestressed Connecting Box Girder Structure%现浇预应力连续箱梁结构引桥的施工质量控制要点

    Institute of Scientific and Technical Information of China (English)

    蔡翔

    2014-01-01

    上海吴淞口国际邮轮码头工程水域设计一座预应力连续箱梁引桥,施工要求很高.分析引桥工程施工特点和难点.着重介绍引桥工程质量控制要点.可供同类工程借鉴.

  20. Monitoring and Analysis of the 85 m Composite Continuous Box Girder after System Transformation in the Non Navigable Part of Hongkong-Zhuhai-Macao Bridge%港珠澳大桥非通航孔85m组合连续箱梁体系转换线形监测与分析

    Institute of Scientific and Technical Information of China (English)

    徐腾飞

    2015-01-01

    港珠澳大桥CB05标浅水区非通航孔桥采用85 m组合连续箱梁结构,全长5440m,共11联,128片组合梁,国内外如此大规模的组合梁桥建设尚属罕见.如何通过线形监测准确而高效地反应组合梁实际线形,对工程本身显得尤为重要.介绍了组合梁安装阶段的主要施工流程,重点阐述了组合梁体系转换步骤;运用Midas/Civil 2012建立了有限元理论模型;结合实际情况布置组合梁顶、底板线形监测点;选取本桥首件工程第八联组合梁为对象,将采集到的线形实测值与理论值进行了对比分析,统计偏差范围,分析偏差出现的原因,为后期改进施工措施、国内组合梁成桥高程验收标准制定以及今后类似工程建设提供了参考和经验.

  1. Discrete vortex method simulations of aerodynamic admittance in bridge aerodynamics

    DEFF Research Database (Denmark)

    Rasmussen, Johannes Tophøj; Hejlesen, Mads Mølholm; Larsen, Allan;

    , and to determine aerodynamic forces and the corresponding flutter limit. A simulation of the three-dimensional bridge responseto turbulent wind is carried out by quasi steady theory by modelling the bridge girder as a line like structure [2], applying the aerodynamic load coefficients found from the current version...... of DVMFLOW in a strip wise fashion. Neglecting the aerodynamic admittance, i.e. the correlation of the instantaneous lift force to the turbulent fluctuations in the vertical velocities, leads to higher response to high frequency atmospheric turbulence than would be obtained from wind tunnel tests....

  2. Fatigue crack detection in a plate girder using Lamb waves

    Science.gov (United States)

    Greve, D. W.; Oppenheim, I. J.; Wu, Wei; Zheng, Peng

    2007-04-01

    We report on the application of wafer-type PZT transducers to the detection of flaws in steel plate girders. In these experiments one transducer is used to emit a pulse and the second receives the pulse and reflections from nearby boundaries, flaws, or discontinuities (pitch-catch mode). In this application there will typically be numerous reflections observed in the undamaged structure. A major challenge is to recognize new reflections caused by fatigue cracks in the presence of these background reflections. A laboratory specimen plate girder was fabricated at approximately half scale, 910 mm deep with an h/t ratio of 280 for the web and a b/t ratio of 16 for the flanges, and with transverse stiffeners fabricated with a web gap at the tension flange. Two wafer-type transducers were mounted on the web approximately 175 mm from the crack location, one on each side of the stiffener. The transducers were operated in pitch-catch mode, excited by a windowed sinusoid to create a narrowband transient excitation. The transducer location relative to the crack corresponded to a total included angle of roughly 30 degrees in the path reflecting from the crack. Cyclic loading was applied to develop a distortion-induced fatigue crack in the web at the web gap location. After appearance of the crack, ultrasonic measurements were performed at a range of center frequencies below the cutoff frequency of the A1 Lamb wave mode. Subsequently the crack was extended mechanically to simulate crack growth under primary longitudinal (bending) stress and the measurements were repeated. Direct differencing of the signals showed arrivals at times corresponding to reflection from the crack location, growing in amplitude as the crack was lengthened mechanically. These results demonstrate the utility of Lamb waves for crack detection even in the presence of numerous background reflections.

  3. Assessing Static Performance of the Dashengguan Yangtze Bridge by Monitoring the Correlation between Temperature Field and Its Static Strains

    OpenAIRE

    Gao-Xin Wang; You-Liang Ding; Peng Sun; Lai-Li Wu; Qing Yue

    2015-01-01

    Taking advantage of the structural health monitoring system installed on the steel truss arch girder of Dashengguan Yangtze Bridge, the temperature field data and static strain data are collected and analyzed for the static performance assessment of the bridge. Through analysis, it is found that the static strain changes are mainly caused by temperature field (temperature and temperature difference) and train. After the train-induced static strains are removed, the correlation between the rem...

  4. Bragg grating structural sensing system for bridge monitoring

    Science.gov (United States)

    Measures, Raymond M.; Alavie, A. Tino; Maaskant, Robert; Ohn, Myo M.; Karr, Shawn E.; Huang, Shang Yuan

    1994-09-01

    Corrosion of steel within bridges and other large concrete structures has become a serious problem and consequently there is growing interest in replacing the steel within such structures with carbon fiber based composite materials. The first highway bridge in the world to use carbon fiber composite prestressing tendons was constructed and opened to the public in the fall of 1993. This two span bridge was also unique in another respect, it is the first highway bridge in the world to have been built with a set of fiber optic Bragg grating sensors structurally integrated into several of its precast concrete deck support girders. A four-channel fiber laser sensor demodulation system that was rugged, compact and transportable was developed for this project. This demodulation system monitored the changes in the internal strain on all three types (steel and two types of carbon fiber composite) of prestressing tendons over several months. The same structurally integrated fiber optic sensing system has also been used to measure the change in the internal strain within the deck girders arising from both static and dynamic loading of the bridge with a large truck.

  5. Empty Tissue Boxes: Considering Poverty in Diversity Discourse

    Science.gov (United States)

    Cuthrell, Kristen; Ledford, Carolyn; Stapleton, Joy

    2007-01-01

    A preservice teacher doing her internship overhears some of her students asking a classmate why he regularly takes home empty tissue boxes. The boy replies that he builds cities and bridges with his empty boxes. His classmates then ask why he does not just build a city with Legos or building blocks. The preservice teacher listens intently as the…

  6. Strengthening Effect Analysis of RC T-Sectional Girders Strengthened with CFRP Sheets%CFRP布加固钢筋混凝土T梁效果分析

    Institute of Scientific and Technical Information of China (English)

    何广宝

    2014-01-01

    Because of many advantage, such as f being light, high strength and corrosion resistance,car-bon fiber reinforced polymer is widely used in old bridge reinforcement. However, the study on theoretical analysis and numerical simulation is relatively delayed due to its complex mechanical properties com-pared common reinforced concrete girders. The finite element software ANSYS is used to establish an nu-merical simulation model of RC T-sectional girders strengthened with CFRP sheets in the article. The problem of convergence of nonlinear Finite Element Analysis (FEA) is solved in the numerical simulation analysis. The midspan deflection and maximum stress of T-sectional girder after reinforcement reduce by 11.6% and 20.7% respectively compared to initial girder, but the ultimate capacity increases by 52%, which demonstrates that CFRP sheets can improve the mechanical performance of RC beams.%碳纤维复合材料具有轻质、高强以及耐腐蚀等优点,在旧桥加固工程中得到广泛应用,但由于其力学性能和破坏模式比普通钢筋混凝土梁复杂,在理论和数值分析方面的研究相对滞后。依托某T型钢筋混凝土桥梁加固实例,运用ANSYS有限元软件建立模型进行分析,解决了CFRP布加固构件非线性数值求解难以收敛的问题。加固后T型梁的跨中挠度和最大应力相比于加固前分别下降了10.4%和17.1%了,然而极限承载力提升了52%,这表明CFRP布加固可以很好地改善钢筋混凝土梁的受力性能。

  7. Railroad Bridges

    Data.gov (United States)

    Department of Homeland Security — Bridges-Rail in the United States According to The National Bridge Inspection Standards published in the Code of Federal Regulations (23 CFR 650.3), a bridge isA...

  8. Estimation of Curvature Changes for Steel-Concrete Composite Bridge Using Fiber Bragg Grating Sensors

    Directory of Open Access Journals (Sweden)

    Donghoon Kang

    2013-01-01

    Full Text Available This study is focused on the verification of the key idea of a newly developed steel-concrete composite bridge. The key idea of the proposed bridge is to reduce the design moment by applying vertical prestressing force to steel girders, so that a moment distribution of a continuous span bridge is formed in a simple span bridge. For the verification of the key technology, curvature changes of the bridge should be monitored sequentially at every construction stage. A pair of multiplexed FBG sensor arrays is proposed in order to measure curvature changes in this study. They are embedded in a full-scale test bridge and measured local strains, which are finally converted to curvatures. From the result of curvature changes, it is successfully ensured that the key idea of the proposed bridge, expected theoretically, is viable.

  9. Damage identification of a large-span concrete cable-stayed bridge based on genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    ZHU Jinsong; XIAO Rucheng

    2007-01-01

    The global stability of a structure, the stiffness of its main girder and concrete tower, and the variation of the forces of its stay cables are key issues to the safety assessment of an in-service cable-stayed bridge. The efficiency and ratio- nality of local elaborate non-damage-identification could be enhanced by the primary damage identification of cable- stayed bridges on the basis of periodic detection of the cable force and strain monitor in key sections of the main girder. The genetic algorithms of damage identification for cable- stayed bridges were investigated in this paper on the basis of the monitor data of the cable force and strain in a key section of the main girder. A damage detection program for complex civil structure was generated to implement the identification of damage location and extent. The deterioration of the struc- ture was calculated according to the variation of monitor data. It is demonstrated that the results of damage identification from the parametric finite element method are accurate. The method had been verified using a long-span concrete cable- stayed bridge in Ningbo, which has been in use for the past four years.

  10. I-5/Gilman advanced technology bridge project

    Science.gov (United States)

    Lanza di Scalea, Francesco; Karbhari, Vistasp M.; Seible, Frieder

    2000-04-01

    The UCSD led I-5/Gilman Advanced Technology Bridge Project will design and construct a fully functional traffic bridge of advanced composite materials across Interstate 5 in La Jolla, California. Its objective is to demonstrate the use of advanced composite technologies developed by the aerospace industry in commercial applications to increase the life expectancy of new structures and for the rehabilitation of aging infrastructure components. The structure will be a 450 ft long, 60 ft wide cable-stayed bridge supported by a 150 ft A-frame pylon with two vehicular lanes, two bicycle lanes, pedestrian walkways and utility tunnels. The longitudinal girders and pylon will be carbon fiber shells filled with concrete. The transverse deck system will consist of hollow glass/carbon hybrid tubes and a polypropylene fiber reinforced concrete deck with an arch action. Selected cables will be composite. The bridge's structural behavior will be monitored to determine how advanced composite materials perform in civil infrastructure applications. The bridge will be instrumented to obtain performance and structural health data in real time and, where possible, in a remote fashion. The sensors applied to the bridge will include electrical resistance strain gages, fiberoptic Bragg gratings and accelerometers.

  11. Three-dimensional nonlinear flutter analysis of long-span suspension bridges during erection.

    Science.gov (United States)

    Zhang, Xin-jun; Sun, Bing-nan; Xiang, Hai-fan

    2003-01-01

    In this work, the aerodynamic stability of the Yichang Suspension Bridge over Yangtze River during erection was determined by three-dimensional nonlinear flutter analysis, in which the nonlinearities of structural dynamic characteristics and aeroelastic forces caused by large deformation are fully considered. An interesting result obtained was that the bridge was more stable when the stiffening girders were erected in a non-symmetrical manner as opposed to the traditional symmetrical erection schedule. It was also found that the severe decrease in the aerodynamic stability was due to the nonlinear effects. Therefore, the nonlinear factors should be considered accurately in aerodynamic stability analysis of long-span suspension bridges during erection.

  12. Three-dimensional nonlinear flutter analysis of long-span suspension bridges during erection

    Institute of Scientific and Technical Information of China (English)

    张新军; 孙炳楠; 项海帆

    2003-01-01

    In this work, the aerodynamic stability of the Yichang Suspension Bridge over Yangtze River during erection was determined by three-dimensional nonlinear flutter analysis, in which the nonlinearities of structural dynamic characteristics and aeroelastic forces caused by large deformation are fully considered. An interesting result obtained was that the bridge was more stable when the stiffening girders were erected in a non-symmetrical manner as opposed to the traditional symmetrical erection schedule. It was also found that the severe decrease in the aerodynamic stability was due to the nonlinear effects. Therefore, the nonlinear factors should be considered accurately in aerodynamic stability analysis of long-span suspension bridges during erection.

  13. Three-dimensional nonlinear flutter analysis of long-span suspension bridges during erection

    Institute of Scientific and Technical Information of China (English)

    张新军; 孙炳楠; 项海帆

    2003-01-01

    In this work, the aerodynamic stability of the Yichang Suspension Bridge over Yangtze River during erection was determined by three-dimensional nonlinear flutter analysis, in which the nonlinearities of structural dynamic characteristics and aeroelastic forces caused by large deformation are fully considered. An interesting resuh obtained was that the bridge was more stable when the stiffening girders were erected in a non-symmetrical manner as opposed to the traditional symmetrical erection schedule. It was also found that the severe decrease in the aerodynamic stability was due to the nonlinear effects. Therefore, the nonlinear factors should be considered accurately in aerodynamic stability analysis of long-span suspension bridges during erection.

  14. RELATIONSHIP BETWEEN DAMAGE AND CHANGE OF DYNAMIC CHARACTERISTICS IN AN EXISTING BRIDGE FOR VIBRATION-BASED STRUCTURAL HEALTH MONITORING

    Science.gov (United States)

    Miyashita, Takeshi; Tamada, Kazuya; Liu, Cuiping; Iwasaki, Hidenori; Nagai, Masatsugu

    The objective of this study is to understand the relationship between damage and the change of dynamic characteristics in an existing bridge for vibration-based structural health monitoring. Focused bridge is a demolished pedestrian bridge, which is a composite steel girder with two main girders. The first damages are slits by gas cutting, which are given to a lower flange in the lateral direction. Then, outstanding plate in the lower flange is removed along the span. Vibration measurement was carried out in each damage case. As a result, it was confirmed that natural frequencies decreased depending on the progress of damage. Its reduction rate was greater in the modes without torsion. For reproducible analysis, spectral element and finite element analyses were carried out. Analytical results also showed the similar reduction of natural frequencies to measurement.

  15. Static behaviors of long-span cable-stayed bridge; Chodai shachokyo no seiteki kyodo ni kansuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Xu [Saitama Univ., Saitama (Japan). Graduate School; Yamaguchi, H.; Ito, M. [Saitama Univ., Urawa (Japan). Faculty of Engineering

    1996-04-21

    In this study, incremental equation of cable-stayed bridge is formulated by finite element method taking the geometrical nonlinear analysis into account. Then, as an example of designing a bridge with 1500m span, setting up the initial tension, analysis of in-plane behavior caused by live loads as well as analysis of the behavior against wind caused by out-of-plane wind load that are necessary for designing a bridge with 1500m span are carried out. The main results obtained through the study are as follows. As for the cable stayed bridge with 1500m center super long-span having supplementary supporting points between the side arms, the geometrical non-linearity caused by the in-plane design live loads is not remarkable. The effects of wind which acts on girders on analysis of the behaviors against wind are different depending on the aerodynamic performance of the girder and in the case of high wind speed, strong effects on the behavior against wind of the in-plane and screws generate. As the changing of tension of the cable makes influences on the force of in-plane cross section and on displacement of the girder, if the wind speed is very high, the analysis results of the behaviors against wind of in-plane and screws of the cable-stayed bridge may be different depending on in what manner the wind load on the cable to be treated. 16 refs., 16 figs., 1 tab.

  16. Design of the Dongjiang River’s Main Bridge on Conghua-Dongguan Highway%从莞高速东江特大桥主桥设计

    Institute of Scientific and Technical Information of China (English)

    戎泽生

    2014-01-01

    The Dongjiang Grand Bridge,1 377 m in length,was built to serve the purpose of allo-wing Conghua-Dongguan Highway to span the Dongjiang River.Its main bridge adopts an 85 m +2 ×138 m +85 m four-span continuous rigid framework.This bridge is regarded as the key project on the line for its complication in formation and difficulty in design and construction.This paper first presents the design of the main bridge’s construction and the structure computation,and then focuses on analysis of the key aspects in terms of the beam bottom line type selection of box girder,prestressed reinforcement’s ar-rangement and mid-span’s deflection before providing strategies for the tailored design.%东江特大桥为从莞高速跨越东江而设,全长1377 m,主桥采用85 m +2×138 m +85 m 4跨连续刚构方案,本桥结构复杂,设计、施工难度大,是全线的重点控制工程。介绍了主桥的构造设计及结构计算,重点对箱梁梁底线型的选取、预应力布置及跨中下挠几个方面进行分析,并提出设计上的对策。

  17. A Simple Technique to Determine Interface Slip of Stud Connected SCC Girders

    Directory of Open Access Journals (Sweden)

    Rajasankar J.

    2012-01-01

    Full Text Available A simple technique is proposed to compute interface slip of stud connected steel-concrete composite (SCC girders based on the results of a flexure test. The technique makes use of relative longitudinal displacement of the concrete slab and steel beam to calculate the interface slip. In the flexure test of a SCC girder, a cost-effective instrumentation arrangement consisting of mechanical dial gauges is used to measure the relative longitudinal displacement. Responses measured from experiments on SCC girders conducted by the authors are used for numerical implementation and validation of the technique. Alternatively, interface slip is also evaluated by applying an analytical model which is based on first principles of mechanics. The values of interface slip computed by using the proposed technique are found to have close correlation with those of the analytical model. The effect of edge restraint on slip due to friction between steel and concrete is also studied

  18. 咸阳地区夏季混凝土刚构桥温度梯度分析%Concrete Continuous Rigid Frame Bridge Temperature Gradient Analysis of Xianyang Area in Summer

    Institute of Scientific and Technical Information of China (English)

    陈凯旋; 高大峰; 董旭; 路军

    2015-01-01

    In order to obtain the reasonable concrete beam bridge temperature gradient in Xian-yang area,this article established the ANSYS model based on the classical thermodynamics theory via 24hours temperature monitoring of the concrete box girder against the background of Extra-large Bridge on XianXun Highway across the Sanshui River,calculating the theoretical thermal field at the most unfavor-able moment of the bridge in summer(15 o’clock)by means of transient thermal analysis,the value of which was compared with the measured temperature value so as to get the suitable summer concrete beam bridge temperature field distribution;finally,it can be seen that the temperature gradient is rather reasona-ble through comparison between the domestic and foreign highway code.%为了得出咸阳地区合理的混凝土箱梁温度梯度,本文以咸旬高速三水河特大桥为背景,通过对混凝土箱梁进行24 h 温度监控,基于经典热力学理论,建立 ANSYS 模型,采用瞬态热分析,求出该桥梁夏季最不利时刻(15时)的理论的温度场;并用实测温度值与求得的理论温度值比较,得出适合该地区的夏季混凝土箱梁温度场分布图;最后对比国内外公路规范,可知该温度梯度较为合理。

  19. Fiber optic Bragg grating sensor network installed in a concrete road bridge

    Science.gov (United States)

    Maaskant, Robert; Alavie, A. Tino; Measures, Raymond M.; Ohn, Myo M.; Karr, Shawn E.; Glennie, Derek J.; Wade, C.; Tadros, Gamil; Rizkalla, Sami

    1994-05-01

    The installation of a fiber optic Bragg grating strain sensor network in a new road bridge is described. These sensors are attached to prestressing tendons embedded in prefabricated concrete girders. Three types of prestressing tendons are being monitored: conventional steel strand and two types of carbon fibers reinforced plastic tendons. Sensor durability issues are reviewed and the installation is described. Initial measurements indicate that the sensors are operational and provide some early comparison of tendon performance.

  20. Newly developed high performance structural steels for long span bridge construction; Chotaikyo ni shiyosareru shinkozai

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, Y. [Nippon Steel Corp., Tokyo (Japan)

    1998-11-15

    This paper reports new steels for long span bridge construction with the thick steel plate as a main part. On the basis of the high-tension steel utilizing technology examined around 1965, a reheated, quenched-and-tempered martensitic steel plate (HT690) was used for the Onaruto Bridge and Seto Ohashi Bridge in a Honsyu-Shikoku linking project. Moreover, a larger number of quenched martensitic high-tension steel plates (HT670 and HT780) were used for the Yojima Bridge together with existing SM400, SM490, SM520, and SM570 steel plates. The lately built Akashi Kaikyo Ohashi Bridge that is 1990 m between struts is longest in the world. The newly developed steel plate (HT780) for a bridge girder of which weldability was improved for lightening was used actually. To reduce the welding cost or improve the welding environment, this steel plate decreased the preheating temperature for weld cracking prevention in a heat-affected zone from about 100degC to 50degC or less. A new wire (of 1800Mpa in tensile strength) was also used for a cable. In future, the bridge girder will be economically and rationally manufactured by the development of design and construction methods that fully draw the characteristics of the new steel. 33 refs., 9 figs., 2 tabs.

  1. Welding of girders to insert plates of composite steel-concrete structure of tower in Kuwait

    OpenAIRE

    A. Lisiecki; J. Szlek; A. Klimpel

    2007-01-01

    Purpose: A study of influence of preheating and MMA welding technique of tee-joints of plate girders to insert plates of a composite steel-concrete structure of the telecommunication tower, on the properties and quality of the concrete in the region of the insert plate has been carried out.Design/methodology/approach: Studies of thermo-mechanical phenomena during manual arc welding MMA of tee-joints between plate girders and insert plates were carried out to identify possible sources of the ...

  2. Welding of girders to insert plates of composite steel-concrete structure

    OpenAIRE

    A. Klimpel; A. Lisiecki; J. Szlek

    2007-01-01

    Purpose: of this paper: A study of influence of preheating and MMA welding technique of tee-joints of plate girders to insert plates of a composite steel-concrete structure of the telecommunication tower, on the properties and quality of the concrete in the region of the insert plate has been carried out.Design/methodology/approach: Studies of thermo-mechanical phenomena during manual arc welding MMA of tee-joints between plate girders and insert plates were carried out to identify possible s...

  3. Nondestructive Evaluation of Railway Bridge by System Identification Using Field Vibration Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Duc Duy; Hong, Dong Soo; Kim, Jeong Tae [Pukyong National University, Busan (Korea, Republic of)

    2010-12-15

    This paper presents a nondestructive evaluation approach for system identification (SID) of real railway bridges using field vibration test results. First, a multi-phase SID scheme designed on the basis of eigenvalue sensitivity concept is presented. Next, the proposed multi-phase approach is evaluated from field vibration tests on a real railway bridge (Wondongcheon bridge) located in Yangsan, Korea. On the steel girder bridge, a few natural frequencies and mode shapes are experimentally measured under the ambient vibration condition. The corresponding modal parameters are numerically calculated from a three-dimensional finite element (FE) model established for the target bridge. Eigenvalue sensitivities are analyzed for potential model-updating parameters of the FE model. Then, structural subsystems are identified phase-by-phase using the proposed model-updating procedure. Based on model-updating results, a baseline model and a nondestructive evaluation of test bridge are identified

  4. Equivalent Kelvin Impact Model for Seismic Pounding Analysis of Bridges

    Institute of Scientific and Technical Information of China (English)

    DING Yang; YUE Fuqing; LI Zhongxian

    2006-01-01

    Based on Hertz contact theory,a method to determine the parameters of Kelvin impact model for seismic pounding analysis of bridges is proposed.The impact stiffness of Kelvin model is determined by the ratio of maximum impact force to maximum contact deformation,which is calculated based on Hertz contact theory with considering the vibration effect.The restitution coefficient which has great influence on the damping coefficient of Kelvin impact model is investigated by numerical analysis.Numerical results indicate that the impact stiffness of Kelvin impact model increases with the increment of the Hertz contact stiffness,approaching velocity or the length ratio of short to long girders.Vibration effect has remarkable influence on the impact stiffness and cannot be neglected.The restitution coefficient decreases when approaching velocity increases or the length ratio of short girder to long girder decreasing.The practical ranges of impact stiffness and restitution coefficient are obtained as 3 × 108-6 × 108 N/m and 0.6-0.95 respectively.

  5. Laryngeal (Voice Box) Cancer

    Science.gov (United States)

    ... ENTCareers Marketplace Find an ENT Doctor Near You Voice Box (Laryngeal) Cancer Voice Box (Laryngeal) Cancer Patient Health Information News media ... laryngeal cancer can be severe with respect to voice, breathing, or swallowing. It is fundamentally a preventable ...

  6. 质量控制点在金塘大桥钢箱梁防腐涂装工程中的应用%The Application of Quality Control Point in Jintang Bridge Steel Box Beam of Anti-corrosion Engineering

    Institute of Scientific and Technical Information of China (English)

    李勇

    2012-01-01

    介绍了质量控制点设置的原则,在进行工序分析的基础上,成功运用质量控制点对金塘大桥钢箱梁电弧喷涂长效防腐项目进行质量控制,并取得显著成效.为防腐涂装施工企业有效运用质量控制点提高工程质量,提供了一定的借鉴.%The establishment principle of the quality control point was introduced, Base on the a-nalysis of working procedure,the quality control points were successfully applied on Jintang bridge steel box beam arc spray long-term anticorrosion project for quality control, and made significantly effectiveness. A reference was procided for coating of construction enterprises application quality control point to improve the project quality.

  7. Wind Resistant Design of Bridges in Japan Developments and Practices

    CERN Document Server

    Fujino, Yozo; Tanaka, Hiroshi

    2012-01-01

    For long-span bridges, wind action is a dominant factor in their safety and serviceability. A large number of long-span bridges have been built in Japan over the past 30 years, and tremendous amounts of research and technical development have been accomplished in wind resistant design. This book is a compilation of the results of active research and development. Wind resistant design standards generated in Japan are described in the first few chapters. Then comes information such as design wind speed, structural damping, wind tunnel tests, and analyses, which provide the basis of the design standards. Wind-induced vibrations and their control of girders, towers, cables, and other features are explained with examples of field measurements. Comprehensive listings of Japanese experience in vibration control are also presented. Because achieving particularly dynamic safety against wind is still not an easy task, these data and information will be valuable assets for the wind-engineering and bridge-engineering com...

  8. Design of Main Arch of Hutiaomen Bridge on Guangzhou-Zhuhai Railway%广珠铁路虎跳门特大桥主拱设计

    Institute of Scientific and Technical Information of China (English)

    王鹏宇; 刘振标; 罗世东; 王新国

    2012-01-01

    广珠铁路虎跳门特大桥主桥为(120+248+120)m的连续刚构柔性拱组合桥.拱肋采用钢管混凝土结构,由上、中、下弦管组成,弦管内采用C50混凝土,每片拱肋由两管平行管和提篮内倾单管组成,由直腹杆和斜腹杆连接成三肢桁架拱;三角形直腹杆采用矩形钢箱截面,斜腹杆采用圆钢管;全桥拱肋共布置19道横撑;拱座采用实体截面.主桥采用先梁后拱的施工方案.采用MIDAS Civil 2006检算拱肋承载力、结构强度、稳定性等性能,计算结果表明拱肋的静力、动力性能均满足规范要求.%The main bridge of the Hutiaomen Bridge on Guangzhou-Zhuhai Railway is a hy-brid bridge of continuous rigid frame structure and flexible arch with span arrangement (120 + 248 + 120) m. The arch ribs of the bridge employ the concrete-filled steel tube structure formed by the upper, middle and lower chord tubes that are filled in with C50 concrete. Each of the arch ribs is composed of two parallel tubes and an inward inclined tube of basket handle and these tubes are connected into a three-leg (triangular) truss arch by the vertical and inclined web mem-bers, of which a vertical member is the rectangular steel box section while an inclined member is the round steel tube section. The arch ribs of the whole bridge have totally 19 cross bracings, the arch seats are the solid sections and the bridge is constructed by way of erecting the girder first and the arch late. The calculation of the bearing capacity, structural strength and stability behav-ior of the arch ribs is checked by the MIDAS Civil and the results of the checking prove that the static and dynamic behavior of the arch ribs can meet the relevant requirements in the codes.

  9. Maintained ship hull girder ultimate strength reliability considering corrosion and fatigue

    DEFF Research Database (Denmark)

    Hu, Yong; Cui, W.; Pedersen, Preben Terndrup

    2004-01-01

    The prupose of this paper is to propose a methodology to assess the time-variant ultimate strength of ship hull girder under the degradations of corrosion and fatigue. The effects of fatigue cracks on the tensile and compressive residual ultimate strength of stiffened panels and unstiffened plate...

  10. Impact Coefficient Analysis of Long-Span Railway Cable-Stayed Bridge Based on Coupled Vehicle-Bridge Vibration

    Directory of Open Access Journals (Sweden)

    Yongle Li

    2015-01-01

    Full Text Available Compared with medium and small span bridges, very limited attention has been paid on the research of the impact coefficient of long-span railway bridges. To estimate the impact effects of long-span railway bridges subjected to moving vehicles, a real long-span railway cable-stayed bridge is regarded as the research object in this study, and a coupled model of vehicle-bridge system is established. The track irregularities are taken as the system excitation and the dynamic responses of the vehicle-bridge system are calculated. The impact effects on main girder, stayed cable, bearings, and bridge tower are discussed at various vehicle speeds. The results show that different components of the long-span railway cable-stayed bridge have different impact coefficients. Even for each part, the impact coefficient is also different at different local positions. It reveals that the impact coefficients in the actual situation may have significant differences with the related code clauses in the present design codes.

  11. 中朝鸭绿江界河公路大桥耐久性技术研究%Study of Durability Enhancing Techniques for Yalu Boundary River Highway Bridge Connecting China and DPR Korea

    Institute of Scientific and Technical Information of China (English)

    闫大伟

    2014-01-01

    The Yalu Boundary River Highway Bridge is a two-pylon steel box girder cable-stayed bridge with a main span of 636 m .The bridge site is located where the climate is harsh in winter and the meteorological condition is complex ,creating challenges for the durability of the bridge .By the combined use of both the theoretical and experimental methods ,a number of studies were conducted ,including the mixing proportion design of the frost-resisting high performance concrete that has high flow state and is able to resist sea water erosion ,the feasibility of - 10 ~ - 5℃ low temperature welding techniques and the externally-installed vibration absorbers for stay ca-bles .The results of the study indicate that the chosen compressive strength ,shrinking behavior , impermeability and frost and thaw resistant performance of concrete all have superior indexes which meet the design requirements .The trial plates were made to take shape by the welding tech-niques applied to real bridges .The tensile strength in the welding joints of trial plates and the yielding strength ,tensile strength and the extension rate after break of the metals in the welding joints could meet the requirements .The feasigility of - 10 ~ - 5 ℃ low temperature welding is proved feasible .And according to the testing results ,the quality control measures for the steel box girder heat preservation ,preheating and other low temperature welding were determined . The pendulum leverage mass vibration dampers featuring the eddy current damping and friction damp -ing for stay cables have sound vibration damping effect and temperature stability .The application of the aforementioned techniques ensures that the bridge has sound durability .%中朝鸭绿江界河公路大桥为主跨636 m 的双塔双索面钢箱梁斜拉桥,桥址处气候严寒,气象条件复杂。为解决桥梁耐久性问题,通过理论与试验相结合的方法,进行高流态耐海水侵蚀的抗冻性高性

  12. Optimization of Dead Load State in Earth-Anchored Cable-Stayed Bridges

    Institute of Scientific and Technical Information of China (English)

    Bin Sun∗; Rucheng Xiao

    2015-01-01

    In order to determine the reasonable completed dead load state in earth⁃anchored cable⁃stayed bridges, a practical method is proposed. The method is based on the rigidly supported continuous beam method and the feasible zone method, emphasizing on the mutual effect between the self⁃anchored structural parts and the earth⁃anchored ones. Three cable⁃stayed bridge models are designed with the main spans of 1 400 m, including a partially earth⁃anchored cable⁃stayed bridge, a cable⁃stayed⁃suspension bridge and a fully self⁃anchored cable⁃stayed bridge, in which the C50 concrete and Q345 steel are adopted. The partially earth⁃anchored cable⁃stayed bridge and the cable⁃stayed⁃suspension bridge secure lower compressive force in the girder than the fully self⁃anchored cable⁃stayed bridge by 25 percent at least. The same is for the material consumption of the whole bridge. Furthermore, the anchor volume is more than 20% lower in the partially earth⁃anchored cable⁃stayed bridge than that in the cable⁃stayed⁃suspension bridge. Consequently, the practical span of cable⁃stayed bridges can be accordingly extended.

  13. 缆索吊装在高速公路箱形拱桥中的应用%The Application of Hoisting Cable on the Box Arch Bridge of Highway

    Institute of Scientific and Technical Information of China (English)

    刘晓燕

    2013-01-01

    缆索吊装指的是利用悬挂的缆索运输和安装构件的施工方法,本文介绍了缆索吊装在高速公路大跨径拱桥施工中的应用。%The hoisting cable refers to the method of using the suspended cable to transport and instal components in the co-nstruction. This article introduces the hoisting cable applied in the highway construction of long-span arch bridge.

  14. 孟庙至平顶山铁路钢管混凝土拱加劲连续梁桥设计%Design of Continuous Beam Bridge Stiffened by Concrete-Filled Steel Tubular Arch on Mengmiao-Pingdingshan Railway

    Institute of Scientific and Technical Information of China (English)

    陈卫华; 龙俊贤

    2016-01-01

    孟庙至平顶山铁路跨311国道特大桥主桥为(32+100+32) m钢管混凝土拱加劲连续梁桥,平面位于R=1600 m的曲线上。主梁为预应力混凝土双纵箱梁结构,纵梁间桥面结构采用纵、横梁体系格子梁,纵梁为单箱单室截面,沿纵向等宽、变高度;在100 m 主跨上方,对应于双纵梁设2道变高度钢管混凝土拱肋加劲,2道拱肋间采用空心钢管组成的3道横撑实现横向连接,每道拱肋由2根钢管组成,拱肋钢管及实腹段内填筑C50微膨胀混凝土;每道拱肋下设13组吊杆,每组吊杆的纵向间距为6 m。采用有限元程序MIDAS建立主桥有限元模型,进行静、动力特性分析,采用ANSYS建立拱脚处空间实体模型对拱脚处局部应力进行分析,分析结果表明该桥各项静、动力特性均满足要求。%The main bridge of the Bridge crossing the No .311 National Highway on the Meng‐miao‐Pingdingshan Railway is a (32+100+32) m continuous beam bridge stiffened by concrete‐filled steel tubular arch .T he plan curvature of the bridge is 1 600 m .T he main girder consists of two longitudinal prestressed concrete box structures ,on which the lattice bridge deck system that is formed of longitudinal and transverse beams rests .The longitudinal beams adopt the single cell single box section ,with constant width and varying height along the bridge length .Above the 100 m long main span ,just over the two longitudinal box beam structures ,two varying‐height con‐crete‐filled steel tubular arch ribs were installed ,aiming to stiffen the longitudinal box beams .Be‐tween the two arch ribs ,three pairs of lateral bracings made of void steel tubes were added to form transverse connection .Each arch rib consists of two steel tubes ,which together with the solid‐spandrel section were filled with C50 micro‐expansive concrete .13 pairs of hangers were tensioned from each arch rib ,spaced by 6 m along the

  15. 东莞东江大桥防腐涂装设计%Design of Corrosion Protection Coating for Dongguan Dongjiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    傅战工; 徐恭义

    2011-01-01

    Dongguan Dongjiang River Bridge is a continuous steel truss girder bridge stiffened by rigid suspension members and the site where the bridge is located is in the severe corrosion environment. Through comparison of the performance indices of the epoxy zinc rich premier, alcohol-soluble inorganic silicate zinc rich premier, water-base inorganic silicate zinc rich premier and spraying metal that have been commonly used as the corrosion protection systems for the exterior surfaces of steel structure, in the light of the characteristics of the different structural parts of the bridge and also in comprehensive consideration of the durability, environmental protection, costsaving and maintainability, it was determined that the epoxy zinc rich coating system was to be used for the corrosion protection of the exterior surfaces and high-strength bolt heads of the main trusses, the water-base inorganic silicate zinc rich coating system for the stringers, cross beams and inspection trolley, the electric arc spraying aluminum for the frictional surfaces of the bolts,the light color modified epoxy asphalt for the interior surfaces ofthe box members, the galvanization layer and sealing paint for the steel crush barriers, the resin coating for the balustrades on the sidewalks and the hot-dipped galvanization for the drainage steel pipes of the bridge.%东莞东江大桥为刚性悬索加劲连续钢桁梁桥,桥位处于较严重的腐蚀环境.通过对环氧富锌底漆、醇溶性无机硅酸富锌底漆、水性无机硅酸富锌底漆和喷涂金属等钢结构外表面常用防腐体系的性能指标比较,针对不同结构部位的特点,综合考虑耐久性、环保性、经济性和可维护性,主桁外表面和螺栓头采用环氧富锌体系防腐;纵、横梁和检查车采用水性无机富锌体系防腐;高强螺栓摩擦面采用电弧喷铝防腐;箱形杆件内表面采用淡色改性环氧沥青漆防腐;钢防撞栏采用镀锌层加封闭漆防腐;人

  16. Myocardial Bridging

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    2016-02-01

    Full Text Available Abstract Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results.

  17. ST60塔式支撑架体系在鹦鹉洲长江大桥接线工程中的应用%The Application of ST60 Tower Bracing Frame in the Bridge Connection of Yingwuzhou Yangtze Bridge

    Institute of Scientific and Technical Information of China (English)

    曾翔鸿

    2015-01-01

    The bridge connection of Wuhan Yingwuzhou Yangtze Bridge in Hanyang is an essential part of the 2nd Ring of the city .Being a critical process of cast-in-site concrete box girder construction ,ST60 tower bracing frame is a breakthrough of traditional bracing frame .Compared with the bowl-buckle full-framing bracing frame ,ST60 tower bracing frame is easy to operate ,efficient and safe with great loading capacity and low cost .By analyzing the application of ST60 tower bracing frame and making a comparative analysis with traditional bracing frame ,the paper aims at summarizing its characteristics in practice so as to promote its further application .%武汉鹦鹉洲长江大桥汉阳接线工程是武汉市二环线的重要组成部分,支架是现浇砼箱梁施工的关键过程.ST60塔式支撑架体系作为国内一种新型的施工工艺用于鹦鹉洲长江大桥汉阳接线工程,是对传统支架的突破.相对于碗扣式满堂支撑架体系 ,ST60塔式支撑架体系重点体现在施工简单、高效、安全、承载力大、成本低.介绍了ST60塔式支撑架体系的施工工艺、方案设计、塔架安装及施工控制要点 ,总结了该体系的应用特点 ,便于进一步推广使用.

  18. Straw in a Box

    Science.gov (United States)

    Jerrard, Richard; Schneider, Joel; Smallberg, Ralph; Wetzel, John

    2006-01-01

    A problem on a state's high school exit exam asked for the longest straw that would fit in a box. The examiners apparently wanted the length of a diagonal of the box, but the figure accompanying the question suggested otherwise--that the radius of the straw be considered. This article explores that more general problem.

  19. ALUMINUM BOX BUNDLING PRESS

    Directory of Open Access Journals (Sweden)

    Iosif DUMITRESCU

    2015-05-01

    Full Text Available In municipal solid waste, aluminum is the main nonferrous metal, approximately 80- 85% of the total nonferrous metals. The income per ton gained from aluminum recuperation is 20 times higher than from glass, steel boxes or paper recuperation. The object of this paper is the design of a 300 kN press for aluminum box bundling.

  20. Shaping 3-D boxes

    DEFF Research Database (Denmark)

    Stenholt, Rasmus; Madsen, Claus B.

    2011-01-01

    Enabling users to shape 3-D boxes in immersive virtual environments is a non-trivial problem. In this paper, a new family of techniques for creating rectangular boxes of arbitrary position, orientation, and size is presented and evaluated. These new techniques are based solely on position data...

  1. The mirror box

    Science.gov (United States)

    Thompson, Gene; Mathieson, Don

    2001-11-01

    The mirror box is an old standby in magic shows and an impressive demonstration of the law of reflection for the physics instructor. The box creates the illusion of an object floating in space by the use of a plane mirror.

  2. Boxing with neutrino oscillations

    Science.gov (United States)

    Wagner, D. J.; Weiler, Thomas J.

    1999-06-01

    We develop a characterization of neutrino oscillations based on the coefficients of the oscillating terms. These coefficients are individually observable; although they are quartic in the elements of the unitary mixing matrix, they are independent of the conventions chosen for the angle and phase parametrization of the mixing matrix. We call these reparametrization-invariant observables ``boxes'' because of their geometric relation to the mixing matrix, and because of their association with the Feynman box diagram that describes oscillations in field theory. The real parts of the boxes are the coefficients for the CP- or T-even oscillation modes, while the imaginary parts are the coefficients for the CP- or T-odd oscillation modes. Oscillation probabilities are linear in the boxes, so measurements can straightforwardly determine values for the boxes (which can then be manipulated to yield magnitudes of mixing matrix elements). We examine the effects of unitarity on the boxes and discuss the reduction of the number of boxes to a minimum basis set. For the three-generation case, we explicitly construct the basis. Using the box algebra, we show that CP violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. The framework presented here will facilitate general analyses of neutrino oscillations among n>=3 flavors.

  3. HULL GIRDER PROGRESSIVE COLLAPSE ANALYSIS USING IACS PRESCRIBED AND NLFEM DERIVED LOAD - END SHORTENING CURVES

    Directory of Open Access Journals (Sweden)

    Stanislav Kitarović

    2016-06-01

    Full Text Available This paper considers the hull girder ultimate strength of a bulk carrier at its midship section, as determined by an incremental-iterative progressive collapse analysis method prescribed by the International Association of Classification Societies Common Structural Rules for Bulk Carriers. In addition to the originally prescribed load – end shortening curves, curves determined by the nonlinear finite element method analysis (considering the influence of the idealized initial geometrical imperfections are also considered. Results obtained by both sets of curves are compared and discussed on both local (structural components load – end shortening curve and global (hull girder ulti-mate bending capacity and collapse sequence level, for both sagging and hogging cases.

  4. Analysis of Train-induced Bridge Vibration and Noise Based on Beam-plate Hybrid Elements%梁-板混合单元分析桥梁车致振动与噪声

    Institute of Scientific and Technical Information of China (English)

    张迅; 张健强; 李小珍

    2015-01-01

    在平截面的假定条件下,通过建立梁—板混合单元有限元模型,采用车—线—桥耦合振动分析得到桥梁高频振动响应,再采用声学边界元法分析桥梁结构噪声。以32 m混凝土简支箱梁为例,讨论了不同的梁—板混合模型对计算精度和效率的影响,并与现场试验结果进行对比。由此验证了:在梁—板混合有限元模型中,跨中板单元区域的长度取5倍以上梁高时,桥梁高频振动和结构噪声仿真值均能取得良好的精度,计算效率可提高70%左右。桥梁振动和结构噪声的峰值频率范围为40 Hz~80 Hz,在梁侧传播时具有一定的指向性。采用梁—板混合单元模型计算得到30 m范围内的结构噪声与全板单元模型计算结果基本一致,但在30 m范围外,前者的计算值要比后者小2 dB(Lin)左右。因而,梁—板混合单元模型可有助于提高桥梁车致振动和噪声分析的效率。%Computational efficiency is a bottleneck in calculating train-induced high-frequency bridge vibration and as-sociated structure-borne noise. In this paper, based on the plane cross-section assumption, the beam-plate hybrid elements were introduced and the train-track-bridge coupling finite element model was built for analyzing the high-frequency vibra-tion response of the bridge. Then, the acoustical boundary element method was used to compute the structure-borne noise. Taking a 32 m simply-supported box-girder as an example, the computational efficiency and accuracy were investigated through different beam-plate combination models. A field test was also carried out for verification. Results show that if the length of the plate-element region exceeds five times of the height of the girder, the computational efficiency can be raised by 70%without loss of accuracy in comparison with the conventional finite element analysis with plate elements. The domi-nant frequency of bridge vibration and the

  5. Dynamic characterization and damage detection in the I-40 bridge over the Rio Grande

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, C.R.; Baker, W.E.; Bell, T.M.; Cone, K.M.; Darling, T.W.; Duffey, T.A.; Eklund, A.; Migliori, A.

    1994-06-01

    In the 1960`s and 1970`s over 2500 bridges were built in the U.S. with a design similar to those on Interstate 40 over the Rio Grande in Albuquerque, New Mexico. These bridges were built without structural redundancy and typically have only two plate girders carrying the entire dead and live loads. Failure of either girder is assumed to produce catastrophic failure of the bridge, hence these bridges are referred to as fracture-critical bridges. The Federal Highway Administration (FHWA) and the National Science Foundation (NSF) have provided funds to New Mexico State University (NMSU) through the New Mexico State Highway and Transportation Department (NMSH&TD) and The Alliance For Transportation Research (ATR) for evaluation and testing of the existing fracture critical bridges over the Rio Grande. Because the 1-40 bridges over the Rio Grande were to be razed during the summer of 1993, the investigators were able to introduce simulated fatigue cracks, similar to those observed in the field, into the structure in order to test various damage identification methods and to observe the changes in load paths through the structure caused by the cracking. To support this research effort, NMSU contracted Los Alamos National Laboratory (LANL) to perform experimental modal analyses, and to develop experimentally verified numerical models of the bridge. Scientists from the LANL`s Condensed Matter and Thermal Physics Group (P-10) applied state-of-the-art sensors and data acquisition software to the modal tests. Engineers from the LANL`s Advanced Engineering Technology Group (MEE-13) conducted ambient and forced vibration tests to verify detailed and simplified finite element models of the bridge. Forced vibration testing was done in conjunction with engineers from Sandia National Laboratory (SNL) who provided and operated a hydraulic shaker.

  6. Locally Corroded Stiffener Effect on Shear Buckling Behaviors of Web Panel in the Plate Girder

    Directory of Open Access Journals (Sweden)

    Jungwon Huh

    2015-01-01

    Full Text Available The shear buckling failure and strength of a web panel stiffened by stiffeners with corrosion damage were examined according to the degree of corrosion of the stiffeners, using the finite element analysis method. For this purpose, a plate girder with a four-panel web girder stiffened by vertical and longitudinal stiffeners was selected, and its deformable behaviors and the principal stress distribution of the web panel at the shear buckling strength of the web were compared after their post-shear buckling behaviors, as well as their out-of-plane displacement, to evaluate the effect of the stiffener in the web panel on the shear buckling failure. Their critical shear buckling load and shear buckling strength were also examined. The FE analyses showed that their typical shear buckling failures were affected by the structural relationship between the web panel and each stiffener in the plate girder, to resist shear buckling of the web panel. Their critical shear buckling loads decreased from 82% to 59%, and their shear buckling strength decreased from 88% to 76%, due to the effect of corrosion of the stiffeners on their shear buckling behavior. Thus, especially in cases with over 40% corrosion damage of the vertical stiffener, they can have lower shear buckling strength than their design level.

  7. The vibration research of the AC dipole-girder system for CSNS/RCS

    CERN Document Server

    Renhong, Liu; Huamin, Qu; Ling, Kang; Motuo, Wang; Guangyuan, Wang; Haijing, Wang

    2013-01-01

    China spallation neutron source(CSNS) is a high intensity proton accelerator based facility, and its accelerator complex includes two main parts: an H- linac and a rapid cycling synchrotron(RCS). The rcs accumulates the 80MeV proton beam, and accelerates it to 1.6GeV, with a repetition rate of 25 Hz. The AC dipole of the RCS is operated at a 25Hz sinusoidal alternating current which causes severe vibration. The vibration will influence the long-term safety and reliable operation of the magnet. The dipole magnet of RCS is active vibration equipment which is different with ground vibration accelerator. It is very important to design and research the dynamic characteristic of the dipole-girder system. This paper takes the dipole and girder as a specific model system, a method for researching the dynamic characteristic of the system is put forward by combining theoretical calculation with experimental testing. The ansys simulation method plays a very important role in the girder structure design stage. With the m...

  8. Study the vibration and dynamic response of the dipole girder system for CSNS/RCS

    CERN Document Server

    Renhong, Liu; JunSong, Zhang; GuangYuan, Wang

    2015-01-01

    China Spallation Neutron Source is a high intensity proton accelerator based facility, and its accelerator complex includes two main parts an H- linac and a rapid cycling synchrotron. The RCS accumulates the 80MeV proton beam, and accelerates it to 1.6GeV, with a repetition rate of 25Hz. The dipole of the CSNS RCS is operated at a 25 Hz sinusoidal alternating current which causes severe vibrate. The vibration will influence the long term safety and reliable operation of the magnet. The dipole of the CSNS RCS is an active vibration equipment which is different from the ground vibration accelerator. It is very important to design and study the dynamic characteristics of the dipole girder system. This paper takes the dipole and girder as a specific model system, a method for studying the dynamic characteristics of the system is put forward by combining theoretical calculation with experimental testing. The modal parameters with and without vibration isolator of the dipole girder system are obtain through ANSYS s...

  9. 基于可靠度的组合桥梁设计及维护策略%Reliability-Based Design and Maintenance Strategy for Composite Bridges

    Institute of Scientific and Technical Information of China (English)

    张慕圣; 陈锐斌

    2012-01-01

    Currently,the design practice of highway bridges around the world are moving towards limit states design,a reliability-based design procedure.Canadian Highway Bridge Design Code (CHBDC) is the first design code entirely developed based on limit states design philosophy,including foundations and FRP components.However,reliability of a structure decreases in service due to environmental attacks and material deterioration such as fatigue,corrosion and many other reasons.Therefore,the structure should be inspected periodically,and the reliability of the structure should be evaluated according to its age and field data.If its reliability is reduced to a certain level,a repair should be scheduled as well as some preventive maintenance measures should be implemented to prevent further deterioration.Recently,many research works have been conducted to investigate reliability-deterioration mechanisms for each type of infrastructure and its components,optimize the inspection and maintenance strategy,predict remaining service life,estimate its life cycle cost.This paper is focused on the study of reliability-deterioration mechanisms of slab on steel girder bridges due to fatigue and corrosion of steel girders as well as corrosion of reinforcement in the deck slab.Examples will also be given to illustrate the proposed life cycle management strategy for composite slab on steel girder bridges.

  10. Study on Key Technology of Paving the Ballastless Track on Bridge in Wuhan-Guangzhou High-Speed Railway%武广高速铁路桥上铺设无砟轨道关键技术研究

    Institute of Scientific and Technical Information of China (English)

    王森荣

    2012-01-01

    The purpose of this study is to solve a series of technical problems when paving the ballastless track on long-span bridge of Wuhan-Guangzhou High-speed Railway, such as passing through large-scale girder's juncture, installing the rail expansion joints because of the overlarge gird-end rotation and displacement and overlarge temperature-span, the stability of gird-end track slab, laying the turnout on bridge, etc. Through theoretical calculation and analysis based on operation condition and the most adverse factors, several key technical problems of paving the ballastless track on the long-span bridge were solved in Wuhan - Guangzhou High-speed Railway, that are: paving the ballastless tracks on the bridge with the longest span of 168m, paving the ballastless tracks on the bridge with steel box tied-arch, and paving the ballastless tracks on the bridge's turnout zone.%为解决武广高速铁路大跨度桥上铺设无砟轨道时,遇到跨越大梁缝、梁端转角和位移过大、温度跨度太大需设置钢轨伸缩调节器、梁端轨道板稳定性、桥上铺设道岔等系列问题.采用理论计算分析并结合工况实际,充分考虑设计参数的最不利因素,武广高速铁路实现了最大跨度168m桥上铺设无砟轨道,在钢箱系杆拱桥上铺设无砟轨道,在桥上道岔区铺设无砟轨道等技术难题,解决了大跨度桥上铺设无砟轨道若干关键技术难题.

  11. Double-composite rectangular truss bridge and its joint analysis

    Directory of Open Access Journals (Sweden)

    Yongjian Liu

    2015-08-01

    Full Text Available This paper describes a novel composite tubular truss bridge with concrete slab and concrete-filled rectangular chords. With concrete slab plus truss system and joints reinforced with concrete and Perfobond Leiste rib, double composite truss bridge proved to be a fairly suitable solution in negative moment area. Perfobond Leiste shear connector (PBL is widely implemented in the composite structure for its outstanding fatigue resistance. In this pilot bridge, Perfobond Leister ribs (PBR were installed in the truss girder's joints, which played double roles as shear connector and stiffener. An erection method and overall bridge structural analysis were then presented. Typical joints in the pilot bridge were selected to analyze the effect of PBR. Investigation of the effect of PBR in concrete-filled tubular joints was elaborated. Comparison has revealed that concrete-filled tubular joints with PBR have much higher constraint capability than joints without PBR. For rectangular tubular truss, the punching shear force of the concrete filled joint with PBR is approximately 43% larger than that of the joint without PBR. Fatigue performance of the joint installed with PBR was improved, which was found through analysis of the stress concentration factor of joint. The PBR installed in the joints mitigated the stress concentration factor in the chord face. Therefore, the advantages of this new type of bridge are demonstrated, including the convenience of construction using rectangular truss, innovative concept of structural design and better global and local performances.

  12. Discrete vortex method simulations of aerodynamic admittance in bridge aerodynamics

    DEFF Research Database (Denmark)

    Rasmussen, Johannes Tophøj; Hejlesen, Mads Mølholm; Larsen, Allan

    , and to determine aerodynamic forces and the corresponding flutter limit. A simulation of the three-dimensional bridge responseto turbulent wind is carried out by quasi steady theory by modelling the bridge girder as a line like structure [2], applying the aerodynamic load coefficients found from the current version...... of DVMFLOW in a strip wise fashion. Neglecting the aerodynamic admittance, i.e. the correlation of the instantaneous lift force to the turbulent fluctuations in the vertical velocities, leads to higher response to high frequency atmospheric turbulence than would be obtained from wind tunnel tests....... In the present work we have extended the laminar oncoming flow in DVMFLOW to a turbulent one, modelled by seeding the upstream flow with vortex particles synthesized from prescribed atmospheric turbulence velocity spectra [3] . The discrete spectrum is sampled from the continuous spectrum subject to a lower cutoff...

  13. Seismic fragility of a highway bridge in Quebec retrofitted with natural rubber isolators

    Directory of Open Access Journals (Sweden)

    G. H. Siqueira

    Full Text Available This paper presents fragility curves for the evaluation of a highway bridge retrofitted with seismic isolator devices. The object of this study is the Chemin des Dalles bridge over Highway 55 located in Trois-Rivières in Quebec, Canada. A series of synthetic ground motions time histories compatible with eastern Canada are used to capture the uncertainties related to the hazard. The seismic isolator model represents natural rubber bearing placed under the longitudinal girders over the bents and the abutments of the bridge. NRB isolators are placed in these locations to uncouple the movement of the superstructure and the infrastructure, increasing the flexibility of the system and decreasing the forces transmitted to the infrastructure. Finally, a set of fragility curves for the as-built and retrofitted models are compared to evaluate the effectiveness of seismic isolation to decrease the seismic vulnerability of this bridge.

  14. APPLICATION OF ULTRA-HIGH PERFORMANCE CONCRETE TO PEDESTRIAN CABLE-STAYED BRIDGES

    Directory of Open Access Journals (Sweden)

    CHI-DONG LEE

    2013-06-01

    Full Text Available The use of ultra-high performance concrete (UHPC, which enables reducing the cross sectional dimension of the structures due to its high strength, is expected in the construction of the super-long span bridges. Unlike conventional concrete, UHPC experiences less variation of material properties such as creep and drying shrinkage and can reduce uncertainties in predicting time-dependent behavior over the long term. This study describes UHPC’s material characteristics and benefits when applied to super-long span bridges. A UHPC girder pedestrian cable-stayed bridge was designed and successfully constructed. The UHPC reduced the deflections in both the short and long term. The cost analysis demonstrates a highly competitive price for UHPC. This study indicates that UHPC has a strong potential for application in the super-long span bridges.

  15. AHP-VIKOR Bridge Structural System Selection in Urban Areas Tehran: Interchanges Case Study

    Directory of Open Access Journals (Sweden)

    Ali Akbar Ramezanianpour

    2016-10-01

    Full Text Available The selection of “Structural system” is one of the most important factors in any bridge and infrastructure design. Designers perform the structural calculations for the project determines the priorities as well as design and performance criteria. Further analysis of the structural selection problem and the identification of the bridge desirable capabilities, triggered the consideration of analytic hierarchy process (AHP as a possible basis for the decision making. The methodology uses the VIKOR to evaluate the alternatives according to the decision criteria and determine the solution. The methodology was developed by a group of bridge designers involved in design and management of urban infrastructure projects and demonstrated using a Steel Girder bridge in an urban area as an optimum alternative.

  16. Behavior of composite rigid frame bridge under bi-directional seismic excitations

    Directory of Open Access Journals (Sweden)

    Xiaogang Liu

    2014-02-01

    Full Text Available Pushover analysis and time history analysis are conducted to explore the bi-directional seismic behavior of composite steel-concrete rigid frame bridge, which is composed of RC piers and steel-concrete composite girders. Both longitudinal and transverse directions excitations are investigated using OpenSees. Firstly, the applicability of pushover analysis based on the fundamental mode is discussed. Secondly, an improved pushover analysis method considering the contribution of higher modes is proposed, and the applicability on composite rigid frame bridges under bi-directional earthquake is verified. Based on this method, an approach to predict the displacement responses of composite rigid frame bridge under random bi-directional seismic excitations by revising the elasto-plastic demand curve is also proposed. It is observed that the developed method yield a good estimate on the responses of composite rigid frame bridges under bi-directional seismic excitations.

  17. Vibration analysis of concrete bridges during a train pass-by using various models

    Science.gov (United States)

    Li, Qi; Wang, Ke; Cheng, Shili; Li, Wuqian; Song, Xiaodong

    2016-09-01

    The vibration of a bridge must be determined in order to predict the bridge noise during a train pass-by. It can be generally solved with different models either in the time domain or the frequency domain. The computation cost and accuracy of these models vary a lot in a wide frequency band. This study aims to compare the results obtained from various models for recommending the most suitable model in further noise prediction. First, train-track-bridge models in the time domain are developed by using the finite element method and mode superposition method. The rails are modeled by Timoshenko beam elements and the bridge is respectively modeled by shell elements and volume elements. Second, power flow models for the coupled system are established in the frequency domain. The rails are modelled by infinite Timoshenko beams and the bridge is respectively represented by three finite element models, an infinite Kirchhoff plate, and an infinite Mindlin plate model. The vibration at given locations of the bridge and the power input to the bridges through the rail fasteners are calculated using these models. The results show that the shear deformation of the bridge deck has significant influences on the bridge vibration at medium-to-high frequencies. The Mindlin plate model can be used to represent the U-shaped girder to obtain the power input to the bridge with high accuracy and efficiency.

  18. Experimental study on AR fiberglass connectors for bridges made of composite materials

    Directory of Open Access Journals (Sweden)

    Tolosana, N.

    2006-06-01

    Full Text Available One highly relevant aspect in composite material bridgedesing is the study of the shear connectors to be used.Composite material bridges most commonly comprise acomposite deck resting on steel or reinforced concrete girders.This article analyzes the connectors most frequentlyused in such bridges.It also reviews the connectors used in the King StormwaterChannel Bridge, whose fibreglass deck is supported bygirders made of concrete-filled carbon fibre girders.The paper advances proposals for several types of connectorsand discusses the results of push-out test run ona number of prototypes with different geometries.The results are analyzed to identify the optimum model forthe “Autovia del Cantabrico” Overpass, with its 46-m span,carbon fibre girders and AR glass shear connectors.Un aspecto relevante dentro del proyecto de un puenterealizado en materiales compuestos es el estudio de losconectores. El caso mas frecuente de puente en materialescompuestos es aquel que presenta un tablero de materialescompuestos soportado por vigas metalicas o de hormigonarmado. En este trabajo se analizaran los tipos deconectores mas utilizados en este tipo de puentesSe analizaran tambien los conectores utilizados en elKing Stormwater Channel Bridge, donde ademas deltablero en fibra de vidrio, se fabricaron las vigas en fibrasde carbono rellenas de hormigon.En este articulo se propondran varios tipos de conectoresy se presentaran los resultados experimentales correspondientesal ensayo de “push-out” de varios prototipos condiferentes geometrias.Tras evaluar los resultados, se determinara el mas idoneopara su implantacion en el Paso Superior de la Autovia delCantabrico, de 46 metros de luz y que presenta las vigasen fibra de carbono y los conectores de vidrio AR.

  19. Bridge Management Systems

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way....

  20. Pion in a Box

    CERN Document Server

    Bietenholz, W; Horsley, R; Nakamura, Y; Pleiter, D; Rakow, P E L; Schierholz, G; Zanotti, J M

    2010-01-01

    The residual mass of the pion in a finite spatial box at vanishing quark masses is computed with two flavors of dynamical clover fermions. The result is compared with predictions of chiral perturbation theory in the delta regime.

  1. Voice box (image)

    Science.gov (United States)

    The larynx, or voice box, is located in the neck and performs several important functions in the body. The larynx is involved in swallowing, breathing, and voice production. Sound is produced when the air which ...

  2. Boxes and Shelves

    OpenAIRE

    Hughes, Dean

    2008-01-01

    The Boxes and Shelves series from 2008 are are all made from the backing card from discarded writing pads. Boxes and Shelves extended my investigation of quotidian materials and their relationship to the origins of creative toil. Since 1996 my research has sought to identify and locate instances where the 'unmeasurable' meets the measurable. I have consistently employed a range of utilitarian materials such as bus seats, bus tickets, puddles, A4 writing paper, to present a series of 'problem ...

  3. [Boxing: traumatology and prevention].

    Science.gov (United States)

    Cabanis, Emmanuel-Alain; Iba-Zizen, Marie-Thérèse; Perez, Georges; Senegas, Xavier; Furgoni, Julien; Pineau, Jean-Claude; Louquet, Jean-Louis; Henrion, Roger

    2010-10-01

    In 1986, a surgeon who, as an amateur boxer himself was concerned with boxers' health, approached a pioneering Parisian neuroimaging unit. Thus began a study in close cooperation with the French Boxing Federation, spanning 25 years. In a first series of 52 volunteer boxers (13 amateurs and 39 professionals), during which MRI gradually replaced computed tomography, ten risk factors were identified, which notably included boxing style: only one of 40 "stylists" with a good boxing technique had cortical atrophy (4.5 %), compared to 15 % of "sloggers". Changes to the French Boxing Federation rules placed the accent on medical prevention. The second series, of 247 boxers (81 amateurs and 266 professionals), showed a clear improvement, as lesions were suspected in 14 individuals, of which only 4 (1.35 %) were probably due to boxing. The third and fourth series were part of a protocol called "Brain-Boxing-Ageing", which included 76 boxers (11 having suffered KOs) and 120 MRI scans, with reproducible CT and MRI acquisitions (9 sequences with 1.5 T then 3 T, and CT). MRI anomalies secondary to boxing were found in 11 % of amateurs and 38 % of professionals (atrophy, high vascular T2 signal areas, 2 cases of post-KO subdural bleeding). CT revealed sinus damage in 13 % of the amateurs and 19 % of the professionals. The risk of acute and chronic facial and brain damage was underline, along with detailed precautionary measures (organization of bouts, role of the referee and ringside doctor, and application of French Boxing Federation rules).

  4. Infectious disease and boxing.

    Science.gov (United States)

    King, Osric S

    2009-10-01

    There are no unique boxing diseases but certain factors contributing to the spread of illnesses apply strongly to the boxer, coach, and the training facility. This article examines the nature of the sport of boxing and its surrounding environment, and the likelihood of spread of infection through airborne, contact, or blood-borne routes of transmission. Evidence from other sports such as running, wrestling, and martial arts is included to help elucidate the pathophysiologic elements that could be identified in boxers.

  5. Nonneurologic emergencies in boxing.

    Science.gov (United States)

    Coletta, Domenic F

    2009-10-01

    Professional boxing has done an admirable job in promoting safety standards in its particular sport. However, injuries occur during the normal course of competition and, unfortunately, an occasional life-threatening emergency may arise. Although most common medical emergencies in boxing are injuries from closed head trauma, in this article those infrequent but potentially catastrophic nonneurologic conditions are reviewed along with some less serious emergencies that the physician must be prepared to address.

  6. National Bridge Inventory (NBI) Bridges

    Data.gov (United States)

    Department of Homeland Security — The NBI is a collection of information (database) describing the more than 600,000 of the Nation's bridges located on public roads, including Interstate Highways,...

  7. Cable Tester Box

    Science.gov (United States)

    Lee, Jason H.

    2011-01-01

    Cables are very important electrical devices that carry power and signals across multiple instruments. Any fault in a cable can easily result in a catastrophic outcome. Therefore, verifying that all cables are built to spec is a very important part of Electrical Integration Procedures. Currently, there are two methods used in lab for verifying cable connectivity. (1) Using a Break-Out Box and an ohmmeter this method is time-consuming but effective for custom cables and (2) Commercial Automated Cable Tester Boxes this method is fast, but to test custom cables often requires pre-programmed configuration files, and cables used on spacecraft are often uniquely designed for specific purposes. The idea is to develop a semi-automatic continuity tester that reduces human effort in cable testing, speeds up the electrical integration process, and ensures system safety. The JPL-Cable Tester Box is developed to check every single possible electrical connection in a cable in parallel. This system indicates connectivity through LED (light emitting diode) circuits. Users can choose to test any pin/shell (test node) with a single push of a button, and any other nodes that are shorted to the test node, even if they are in the same connector, will light up with the test node. The JPL-Cable Tester Boxes offers the following advantages: 1. Easy to use: The architecture is simple enough that it only takes 5 minutes for anyone to learn how operate the Cable Tester Box. No pre-programming and calibration are required, since this box only checks continuity. 2. Fast: The cable tester box checks all the possible electrical connections in parallel at a push of a button. If a cable normally takes half an hour to test, using the Cable Tester Box will improve the speed to as little as 60 seconds to complete. 3. Versatile: Multiple cable tester boxes can be used together. As long as all the boxes share the same electrical potential, any number of connectors can be tested together.

  8. A New Multiconstraint Method for Determining the Optimal Cable Stresses in Cable-Stayed Bridges

    Directory of Open Access Journals (Sweden)

    B. Asgari

    2014-01-01

    Full Text Available Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM. The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

  9. A new multiconstraint method for determining the optimal cable stresses in cable-stayed bridges.

    Science.gov (United States)

    Asgari, B; Osman, S A; Adnan, A

    2014-01-01

    Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM). The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

  10. Design and Construction of Operation Bridge for Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Kwangsub; Choi, Jinbok; Lee, Jongmin; Oh, Jinho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The operation bridge contains a lower working deck mounted on a saddle that travels on rails. Upright members are mounted on the saddle to support the upper structure and two hoist monorails. The saddle contains an anti-derail system that is composed of seismic lugs and guide rollers. The operation bridge travels along the rails to transport the fuel assembly, irradiated object, and reactor components in the pools by using tools. Hoists are installed at the top girder. The hoist is suspended from the monorail by means of a motor driven trolley that runs along the monorail. Movements of hoist and trolley are controlled by using the control pendant switch. Processes of design and construction of the operation bridge for the research reactor are introduced. The operation bridge is designed under consideration of functions of handling equipment in the pool and operational limits for safety. Structural analysis is carried out to evaluate the structural integrity in the seismic events. Tests and inspections are also performed during fabrication and installation to confirm the function and safety of the operation bridge.

  11. Dynamic responses of cable-stayed bridges to vehicular loading including the effects of the local vibration of cables

    Institute of Scientific and Technical Information of China (English)

    He ZHANG; Xu XIE

    2011-01-01

    Stay cables,the primary load carrying components of cable-stayed bridges (CSBs),are characterised by high flexibility which increases with the span of the bridge.This makes stay cables vulnerable to local vibrations which may have significant effects on the dynamic responses of long-span CSBs.Hence,it is essential to account for these effects in the assessment of the dynamics CSBs.In this paper,the dynamic responses of CSBs under vehicular loads are studied using the finite element method (FEM),while the local vibration of stay cables is analyzed using the substructure method.A case study of a cable-stayed steel bridge with a center span of 448 m demonstrates that stay cables undergo large displacements in the primary mode of the whole bridge although,in general,a cable's local vibrations are not obvious.The road surface roughness has significant effects on the interaction force between the deck and vehicle but little effect on the global response of the bridge.Load impact factors of the main girder and tower are small,and the impact factors of the tension of cables are larger than those of the displacements of girders and towers.

  12. The BOXES Methodology Black Box Dynamic Control

    CERN Document Server

    Russell, David W

    2012-01-01

    Robust control mechanisms customarily require knowledge of the system’s describing equations which may be of the high order differential type.  In order to produce these equations, mathematical models can often be derived and correlated with measured dynamic behavior.  There are two flaws in this approach one is the level of inexactness introduced by linearizations and the other when no model is apparent.  Several years ago a new genre of control systems came to light that are much less dependent on differential models such as fuzzy logic and genetic algorithms. Both of these soft computing solutions require quite considerable a priori system knowledge to create a control scheme and sometimes complicated training program before they can be implemented in a real world dynamic system. Michie and Chambers’ BOXES methodology created a black box system that was designed to control a mechanically unstable system with very little a priori system knowledge, linearization or approximation.  All the method need...

  13. Methods for determination of ultimate load of eccentrically patch loaded steel I-girders

    Directory of Open Access Journals (Sweden)

    Šćepanović, B.

    2014-12-01

    Full Text Available Experimental tests show that most eccentrically patch loaded steel I-girders have a collapse mode quite different from that of centrically loaded girders. Concerning engineering practice, the most important difference between collapse modes is in ultimate load. The reduction in ultimate load with an increase in load eccentricity is obvious in some eccentrically loaded girders. Under certain circumstances, for a certain combination of influential parameters, eccentrically loaded girders behave as if loaded in the web plane, with no or no significant reduction in ultimate load due to load eccentricity. Dealing with such a big number of mutually dependant parameters that influence collapse mode and level of ultimate load reduction due to load eccentricity, still without theoretical formulation of collapse mechanism, two approaches for ultimate load determination are analysed: empirical mathematical expressions and artificial neural networks forecast models. Results of two procedures are compared. Recommendations for application in engineering practice are given.Las pruebas experimentales muestran que la mayoría de vigas en I de acero cargadas excéntricamente tienen un modo de colapso muy diferente del de las vigas cargadas centradas. En cuanto a la práctica de ingeniería, la diferencia más importante entre los modos de colapso es la carga final. La reducción de la carga última con un aumento de la excentricidad de carga es evidente en algunas vigas cargadas excéntricamente, mientras que bajo ciertas circunstancias, para una determinada combinación de parámetros influyentes, las vigas cargadas excéntricamente se comportan como si se carga en el plano del alma, con ninguna reducción significativa en la carga última debido a la carga excéntrica. Se analizan dos métodos para la determinación de la carga máxima: expresiones matemáticas empíricas y redes neuronales artificiales. Los resultados de ambos procedimientos se comparan. Se

  14. Depth in box spaces.

    Science.gov (United States)

    Pont, Sylvia C; Nefs, Harold T; van Doorn, Andrea J; Wijntjes, Maarten W A; Te Pas, Susan F; de Ridder, Huib; Koenderink, Jan J

    2012-01-01

    Human observers adjust the frontal view of a wireframe box on a computer screen so as to look equally deep and wide, so that in the intended setting the box looks like a cube. Perspective cues are limited to the size-distance effect, since all angles are fixed. Both the size on the screen, and the viewing distance from the observer to the screen were varied. All observers prefer a template view of a cube over a veridical rendering, independent of picture size and viewing distance. If the rendering shows greater or lesser foreshortening than the template, the box appears like a long corridor or a shallow slab, that is, like a 'deformed' cube. Thus observers ignore 'veridicality'. This does not fit an 'inverse optics' model. We discuss a model of 'vision as optical user interface'.

  15. Bridge condition assessment based on long-term strain monitoring

    Science.gov (United States)

    Sun, LiMin; Sun, Shouwang

    2011-04-01

    In consideration of the important role that bridges play as transportation infrastructures, their safety, durability and serviceability have always been deeply concerned. Structural Health Monitoring Systems (SHMS) have been installed to many long-span bridges to provide bridge engineers with the information needed in making rational decisions for maintenance. However, SHMS also confronted bridge engineers with the challenge of efficient use of monitoring data. Thus, methodologies which are robust to random disturbance and sensitive to damage become a subject on which many researches in structural condition assessment concentrate. In this study, an innovative probabilistic approach for condition assessment of bridge structures was proposed on the basis of long-term strain monitoring on steel girder of a cable-stayed bridge. First, the methodology of damage detection in the vicinity of monitoring point using strain-based indices was investigated. Then, the composition of strain response of bridge under operational loads was analyzed. Thirdly, the influence of temperature and wind on strains was eliminated and thus strain fluctuation under vehicle loads is obtained. Finally, damage evolution assessment was carried out based on the statistical characteristics of rain-flow cycles derived from the strain fluctuation under vehicle loads. The research conducted indicates that the methodology proposed is qualified for structural condition assessment so far as the following respects are concerned: (a) capability of revealing structural deterioration; (b) immunity to the influence of environmental variation; (c) adaptability to the random characteristic exhibited by long-term monitoring data. Further examination of the applicability of the proposed methodology in aging bridge may provide a more convincing validation.

  16. Opto-Box

    CERN Document Server

    Bertsche, David; The ATLAS collaboration; Welch, Steven; Smith, Dale Shane; Che, Siinn; Gan, K.K.; Boyd, George Russell Jr

    2015-01-01

    The opto-box is a custom mini-crate for housing optical modules, which process and transfer optoelectronic data. The system tightly integrates electrical, mechanical, and thermal functionality into a small package of size 35x10x8 cm^3. Special attention was given to ensure proper shielding, grounding, cooling, high reliability, and environmental tolerance. The custom modules, which incorporate Application Specific Integrated Circuits (ASICs), were developed through a cycle of rigorous testing and redesign. In total, fourteen opto-boxes have been installed and loaded with modules on the ATLAS detector. They are currently in operation as part of the LHC run 2 data read-out chain.

  17. Eye trauma in boxing.

    Science.gov (United States)

    Corrales, Gustavo; Curreri, Anthony

    2009-10-01

    In boxing, along with a few other sports, trauma is inherent to the nature of the sport; therefore it is considered a high-risk sport for ocular injuries. The long-term morbidity of ocular injuries suffered by boxers is difficult to estimate due to the lack of structured long-term follow-up of these athletes. Complications of blunt ocular trauma may develop years after the athlete has retired from the ring and is no longer considered to be at risk for boxing-related injuries. This article describes the wide range of eye injuries a boxer can sustain, and their immediate and long-term clinical management.

  18. Damage Detection for Continuous Bridge Based on Static-Dynamic Condensation and Extended Kalman Filtering

    Directory of Open Access Journals (Sweden)

    Haoxiang He

    2014-01-01

    Full Text Available As an effective and classical method about physical parameter identification, extended Kalman filtering (EKF algorithm is widely used in structural damage identification, but the equations and solutions for the structure with bending deformation are not established based on EKF. The degrees of freedom about rotation can be eliminated by the static condensation method, and the dynamic condensation method considering Rayleigh damping is proposed in order to establish the equivalent and simplified modal based on complex finite element model such as continuous girder bridge. According to the requirement of bridge inspection and health monitoring, the online and convenient damage detection method based on EKF is presented. The impact excitation can be generated only on one location by one hammer actuator, and the signal in free vibration is analyzed. The deficiency that the complex excitation information is needed based on the traditional method is overcome. As a numerical example, a three-span continuous girder bridge is simulated, and the corresponding stiffness, the damage location and degree, and the damping parameter are identified accurately. It is verified that the method is suitable for the dynamic signal with high noise-signal ratio; the convergence speed is fast and this method is feasible for application.

  19. State-of-the-art of long-span bridge engineering in China

    Institute of Scientific and Technical Information of China (English)

    XIANG Haifan; GE Yaojun

    2007-01-01

    This paper introduces the state-of-the-art of long-span bridge engineering in China with emphases on recent long-span bridge projects,bridge deck configuration and material,design codes of long-span bridges and improvement of aerodynamic performance.The recent long-span bridge projects include thirty-eight completed suspension bridges,cable-stayed and arch bridges with a main span over 400 m,and eighteen major bridges are under construction.The bridge deck configuration and material,with prestressed concrete decks,steel-concrete composite decks and steel box decks together with several popular cross-sections,are presented.The third part briefly outlines four design codes,including static and dynamic design for highway long-span bridges,and the recent engineering experiences gained from several aerodynamic vibration control projects of long-span bridges are shared in the last part.

  20. Bridged graphite oxide materials

    Science.gov (United States)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  1. A numerical study on the structural integrity of self-anchored cable-stayed suspension bridges

    Directory of Open Access Journals (Sweden)

    Paolo Lonetti

    2016-10-01

    Full Text Available A generalized numerical model for predicting the structural integrity of self-anchored cable-stayed suspension bridges considering both geometric and material nonlinearities is proposed. The bridge is modeled by means of a 3D finite element approach based on a refined displacement-type finite element approximation, in which geometrical nonlinearities are assumed in all components of the structure. Moreover, nonlinearities produced by inelastic material and second order effects in the displacements are considered for girder and pylon elements, which combine gradual yielding theory with CRC tangent modulus concept. In addition, for the elements of the suspension system, i.e. stays, hangers and main cable, a finite plasticity theory is adopted to fully evaluate both geometric and material nonlinearities. In this framework, the influence of geometric and material nonlinearities on the collapse bridge behavior is investigated, by means of a comparative study, which identifies the effects produced on the ultimate bridge behavior of several sources of bridge nonlinearities involved in the bridge components. Results are developed with the purpose to evaluate numerically the influence of the material and geometric characteristics of self-anchored cable-stayed suspension bridges with respect also to conventional bridge based on cablestayed or suspension schemes

  2. Seismic Response of Long-Span Triple-Tower Suspension Bridge under Random Ground Motion

    Directory of Open Access Journals (Sweden)

    Chang-ke Jiao

    2017-01-01

    Full Text Available Multitower suspension bridge is of different style compared to the traditional suspension bridge with two towers, and consequently the dissimilarity of static and dynamic behaviors is distinct. As a special case of multitower suspension bridge, two long-span triple-tower suspension bridges have been constructed in China and the seismic random response of triple-tower suspension bridges is studied in this paper. A nonlinear dynamic analysis finite element model is established in ABAQUS and the Python language is utilized to facilitate the preprocess and postprocess during the finite element analysis. The procedure for random response calculation of structures based on the pseudoexcitation method is presented, with the initial equilibrium state of structure considered, which may be ignored for long-span bridges during calculating of stochastic response. The stationary seismic random responses of triple-tower suspension bridge under uniform excitation in firm, medium, and soft soil conditions and under spatially varying excitation in soft soil are investigated. The distribution of RMS of random responses of displacements and internal forces of the stiffening girder and towers is presented and discussed in detail. Results show that spatially variable ground motions should be considered in the stochastic analysis of triple-tower suspension bridge.

  3. Study of the aerostatic and aerodynamic stability of super long-span cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    Zhang Xinjun; Sun Hailing

    2014-01-01

    With the increase of span length,the bridge tends to be more flexible,and the wind stability be-comes an important problem for the design and construction of super long-span cable-stayed bridges. By taking a super long-span cable-stayed bridge with a main span of 1 400 m as example,the aerostatic and aerodynamic stability of the bridge are investigated by three-dimensional nonlinear aerostatic and aerodynamic stability analy-sis,and the results are compared with those of a suspension bridge with a main span of 1 385 m,and from the aspect of wind stability,the feasibility of using cable-stayed bridge in super long-span bridge with a main span above 1 000 m is discussed. In addition,the influences of design parameters including the depth and width of the girder,the tower structure,the tower height-to-span ratio,the side-to-main span ratio,the auxiliary piers in the side span and the anchorage system of stay cables,etc on the aerostatic and aerodynamic stability of su-per long-span cable-stayed bridges are investigated numerically;the key design parameters are pointed out,and also their reasonable values are proposed.

  4. Hydrophobic, Porous Battery Boxes

    Science.gov (United States)

    Bragg, Bobby J.; Casey, John E., Jr.

    1995-01-01

    Boxes made of porous, hydrophobic polymers developed to contain aqueous potassium hydroxide electrolyte solutions of zinc/air batteries while allowing air to diffuse in as needed for operation. Used on other types of batteries for in-cabin use in which electrolytes aqueous and from which gases generated during operation must be vented without allowing electrolytes to leak out.

  5. Mystery Box Marvels

    Science.gov (United States)

    Santos, Joel; Centurio, Tina

    2012-01-01

    What happens in the first week of school could very well set the stage for the rest of the school year. Setting high standards for science activities based in inquiry can start on the first day of science class and develop as the year unfolds. With the use of simple, readily available, inexpensive materials, an efficient mystery box lesson can be…

  6. 铁路车桥耦合振动模态法分析%Coupling vibration analysis of vehicle-bridge by mode method

    Institute of Scientific and Technical Information of China (English)

    杨仕若; 曾庆元

    2011-01-01

    The free vibration mode of the truss girder bridge and normal coordinates are taken as displacement functions of the bridge vibration.By coupling the vehicle and the truss girder bridge as one composite system, the total potential energy of the vehicle and the truss girder bridge under normal coordinates are calculated.Based on the principle of the total potential energy with stationary value in elastic system and the set-in-right-position rule for forming structural matrices, the vibration equations of vehicle-bridge are established in time-varying system.The calculation results are compared with the ones by non-mode method.The minimum error of the results by the two methods is 0.16%.The mode method could reduce the degrees of freedom of the vehicle-bridge system, thus it reduces the computing time considerably.%以钢桁梁桥自由振动的模态和正则坐标作为桥跨结构振动的位移函数,将列车-钢桁梁桥作为一个系统,计算正则坐标下钢桁梁桥及车辆的总势能.基于弹性系统的总势能值不变原理及形成矩阵的对号入座法则,建立了车桥时变系统在正则坐标下的振动方程,有效减少了车桥振动的自由度和计算工作量.以某铁路为例,计算了连续钢桁梁桥车桥系统的振动响应,并用模态法和非模态法进行对比,最小误差为0.16%.

  7. An innovative steel-concrete joint for integral abutment bridges

    Directory of Open Access Journals (Sweden)

    Bruno Briseghella

    2015-08-01

    Full Text Available Integral abutment bridges are becoming rather common, due to the durability problems of bearings and expansion joints. At the same time, among short- and medium-span bridges, multi-beam steel-concrete composite deck with hot-rolled girder is an economical and interesting alternative to traditional pre-stressed concrete solutions. The two concepts can be linked together to design integral steel-concrete composite bridges with the benefits of two typologies. The most critical aspect for these bridges is usually the joints between deck and piers or abutments. In this paper, an innovative beam-to-pier joint is proposed and a theoretical and experimental study is introduced and discussed. The analyzed connection is aimed at combining general ease of construction with a highly simplified assembly procedure and a good transmission of hogging and sagging moment at the supports in continuous beams. For this purpose, the traditional shear studs, used at the interface between steel beam and upper concrete slab, are also used at the ends of steel profiles welded horizontally to the end plates. To better understand the behaviour of this kind of joints and the roles played by different components, three large-scale specimens were tested and an FE model was implemented. The theoretical and experimental results confirmed the potential of the proposed connection for practical applications and indicated the way to improve its structural behaviour.

  8. Building Bridges

    DEFF Research Database (Denmark)

    The report Building Bridges adresses the questions why, how and for whom academic audience research has public value, from the different points of view of the four working groups in the COST Action IS0906 Transforming Audiences, Transforming Societies – “New Media Genres, Media Literacy and Trust...... in the Media”, “Audience Interactivity and Participation”, “The Role of Media and ICT Use for Evolving Social Relationships” and “Audience Transformations and Social Integration”. Building Bridges is the result of an ongoing dialogue between the Action and non-academic stakeholders in the field of audience...... Belgrade), Leo Pekkala (Finnish Centre for Media Education and Audiovisual Media/MEKU), Julie Uldam (Network on Civic Engagement and Social Innovation) and Gabriella Velics (Community Media Forum Europe)....

  9. Mathematical bridges

    CERN Document Server

    Andreescu, Titu; Tetiva, Marian

    2017-01-01

    Building bridges between classical results and contemporary nonstandard problems, Mathematical Bridges embraces important topics in analysis and algebra from a problem-solving perspective. Blending old and new techniques, tactics and strategies used in solving challenging mathematical problems, readers will discover numerous genuine mathematical gems throughout that will heighten their appreciation of the inherent beauty of mathematics. Most of the problems are original to the authors and are intertwined in a well-motivated exposition driven by representative examples. The book is structured to assist the reader in formulating and proving conjectures, as well as devising solutions to important mathematical problems by making connections between various concepts and ideas from different areas of mathematics. Instructors and educators teaching problem-solving courses or organizing mathematics clubs, as well as motivated mathematics students from high school juniors to college seniors, will find Mathematical Bri...

  10. Plastic Bridge

    Institute of Scientific and Technical Information of China (English)

    履之

    1994-01-01

    Already ubiquitous in homes and cars, plastic is now appearing inbridges. An academic-industrial consortium based at the University ofCalifornia in San Diego is launching a three-year research program aimed atdeveloping the world’s first plastic highway bridge, a 450-foot span madeentirely from glass-,carbon,and polymer-fiber-reinforced composite mate-rials, the stuff of military aircraft. It will cross Interstate 5 to connect thetwo sides of the school’s campus.

  11. ExBox: a polycyclic aromatic hydrocarbon scavenger.

    Science.gov (United States)

    Barnes, Jonathan C; Juríček, Michal; Strutt, Nathan L; Frasconi, Marco; Sampath, Srinivasan; Giesener, Marc A; McGrier, Psaras L; Bruns, Carson J; Stern, Charlotte L; Sarjeant, Amy A; Stoddart, J Fraser

    2013-01-09

    A template-directed protocol, which capitalizes on donor-acceptor interactions, is employed to synthesize a semi-rigid cyclophane (ExBox(4+)) that adopts a box-like geometry and is comprised of π-electron-poor 1,4-phenylene-bridged ("extended") bipyridinium units (ExBIPY(2+)). ExBox(4+) functions as a high-affinity scavenger of an array of different polycyclic aromatic hydrocarbons (PAHs), ranging from two to seven fused rings, as a result of its large, accommodating cavity (approximately 3.5 Å in width and 11.2 Å in length when considering the van der Waals radii) and its ability to form strong non-covalent bonding interactions with π-electron-rich PAHs in either organic or aqueous media. In all, 11 PAH guests were observed to form inclusion complexes with ExBox(4+), with coronene being the largest included guest. Single-crystal X-ray diffraction data for the 11 inclusion complexes ExBox(4+)⊂PAH as well as UV/vis spectroscopic data for 10 of the complexes provide evidence of the promiscuity of ExBox(4+) for the various PAHs. Nuclear magnetic resonance spectroscopy and isothermal titration calorimetric analyses of 10 of the inclusion complexes are employed to further characterize the host-guest interactions in solution and determine the degree with which ExBox(4+) binds each PAH compound. As a proof-of-concept, a batch of crude oil from Saudi Arabia was subjected to extraction with the water-soluble form of the PAH receptor, ExBox·4Cl, resulting in the isolation of different aromatic compounds after ExBox·4Cl was regenerated.

  12. Influence of ballastless track constraint on the seismic responses of high-speed railway train-bridge system%无砟轨道约束对高速铁路列车-桥梁系统地震响应的影响

    Institute of Scientific and Technical Information of China (English)

    陈令坤; 蒋丽忠; 余志武

    2013-01-01

    The high-speed train (motor car/trailer car) model with 38 DOFs was build up ,based on the nonlinear Hertz contact theory and the Kalker creep theory ,the strong earthquake records of PEER-NGA were introduced ,the fine model of the high-speed train-ballastless track/rail-box girder-bearing-pier-pier-soil were established in this paper ,the influence of bearing and pile-soil dynamic interaction were considered ,CRTSⅡslab ballastless track and 32 m span simply-supported box girder bridge were studied ,the MATLAB software was developed to calculated the seismic responses and train-running safety during earthquake of high-speed railway train-bridge system ,and the comparative analysis was carried out .The calculated results show that ,the seismic response of the system were larger compared with the high-speed train-ballastless track-bridge system ,the constraint influence of the ballastless track can not be ignored ,the ballastless track can effectively improve the train-running safety behavior of vehi-cle with/without earthquake action ;the pulse like fault earthquake can significantly affected the respon-ses of high-speed railway train-ballastless track-bridge system and train-running safety .%建立了38自由度高速列车(动车/拖车)空间振动模型,基于非线性Hertz接触理论和Kalker线性蠕滑理论,引进PEER-NGA强震记录,建立地震作用下的高速铁路列车-无砟轨道/钢轨-桥梁-支座-桥墩-桩土系统精细计算模型,考虑支座刚度和桩土作用及近场地震效应的影响,以高速铁路32 m跨简支箱梁桥和CRTSⅡ板式无砟轨道为研究对象,编制了MATLAB程序,计算了有/无砟轨道约束下高速列车-桥梁时系统的地震响应。计算结果表明,不考虑三层无砟轨道时列车-桥梁系统模型由于桥梁刚度过大,列车-无砟轨道-桥梁系统的各项地震响应较列车-钢轨-桥梁系统有较大增加;对于有/无地震作用时,采用无砟轨道

  13. Design of Main Bridge of Guizhou Wujiang River Bridge%贵州乌江大桥主桥设计

    Institute of Scientific and Technical Information of China (English)

    张伟; 曹洪武; 易伦雄

    2013-01-01

    The main bridge of Guizhou Wujiang River Bridge is a 325 m single-span suspension bridge of simply-supported concrete slab stiffening girder. The cross section of the stiffening girder is the dumbbell section, the towers are the portal frame structures of rectangular solid sections and are supported on the dug pile foundations. The anchorage of the bridge on the Xifeng bank is the gravity anchorage while on the Jinsha bank is the tunnel-type anchorage. The main cables consist of the ψ5. 1 mm high-strength galvanized steel wires and the suspenders are made up of the #3. 0 mm low-relaxation and high-strength galvanized parallel steel wires. The software MIDAS Civil 2006 was used to analyze the spatial global force conditions of the bridge and the software FLAC3D was used as well to carry out the three-dimensional elastoplastic numerical calculation and analysis of the tunnel-type anchorage and its surrounding rock. The results of the analysis showed that the various checking calculations of the bridge could meet the relevant requirements in the codes.%贵州乌江大桥主桥为325m单跨简支混凝土板式加劲梁悬索桥.该桥加劲梁采用哑铃形截面;桥塔采用门形框架结构,矩形实心截面,采用挖孔灌注桩基础;息烽岸采用重力锚碇,金沙岸采用隧道锚碇;主缆采用φ5.1 mm镀锌高强钢丝,吊索采用φ5.0 mm低松弛镀锌高强平行钢丝.采用MIDAS Civil 2006软件对该桥进行空间整体受力分析,并采用FLAC3D软件对隧道锚及围岩进行三维弹塑性数值计算分析,结果表明该桥各项检算均满足规范要求.

  14. Making Connections with Memory Boxes.

    Science.gov (United States)

    Whatley, April

    2000-01-01

    Addresses the use of children's literature within the social studies classroom on the topic of memory boxes. Includes discussions of four books: (1) "The Littlest Angel" (Charles Tazewell); (2) "The Hundred Penny Box" (Sharon Bell Mathis); (3) "Wilfrid Gordon McDonald Partridge" (Mem Fox); and (4) "The Memory Box" (Mary Bahr). (CMK)

  15. Opto-Box

    CERN Document Server

    Bertsche, David; The ATLAS collaboration

    2015-01-01

    The opto-box is a custom mini-crate for housing optical modules, which process and transfer optoelectronic data. Many novel solutions were developed for the custom design and manufacturing. The system tightly integrates electrical, mechanical, and thermal functionality into a small package of size 35x10x8 cm$^{3}$. Special attention was given to ensure proper shielding, grounding, cooling, high reliability, and environmental tolerance. The custom modules, which incorporate Application Specific Integrated Circuits (ASICs), were developed through a cycle of rigorous testing and redesign. In total, fourteen opto-boxes have been installed and loaded with modules on the ATLAS detector. They are currently in operation as part of the LHC run 2 data read-out chain.

  16. Boxed Permutation Pattern Matching

    DEFF Research Database (Denmark)

    Amit, Mika; Bille, Philip; Cording, Patrick Hagge;

    2016-01-01

    the goal is to only find the boxed subsequences of T that are order-isomorphic to P. This problem was introduced by Bruner and Lackner who showed that it can be solved in O(n3) time. Cho et al. [CPM 2015] gave an O(n2m) time algorithm and improved it to O(n2 logm). In this paper we present a solution...

  17. The Box Method

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm

    The velocity level in a room ventilated by jet ventilation is strongly influenced by the supply conditions. The momentum flow in the supply jets controls the air movement in the room and, therefore, it is very important that the inlet conditions and the numerical method can generate a satisfactory...... description of this momentum flow. The Box Method is a practical method for the description of an Air Terminal Device which will save grid points and ensure the right level of the momentum flow....

  18. The Electronic Battle Box

    Science.gov (United States)

    Gouin, Denis; Turcotte, Guy; Lebel, Eric; Gilbert, Annie

    2000-08-01

    The Electronic Battle Box is an integrated suite of planning and decision-aid tools specially designed to facilitate Canadian Armed Force Officers during their training and during their tasks of preparing and conducting military operations. It is the result of a collaborative effort between the Defence Research Establishment Valcartier, the Directorate of Army Doctrine (DAD), the Directorate of Land Requirements (DLR), the G4 staff of 1Cdn Div HQ and CGI Information and Management Consultants Inc. Distributed on CD-ROM, the Electronic Battle Box contains efficient and user-friendly tools that significantly reduce the planning time for military operations and ensure staff officers a better focus on significant tasks. Among the tools are an OrBat Browser and an Equipment Browser allowing to view and edit military organizations, a Task Browser providing facilities to prepare plans using Gantt charts, a Logistic Planner allowing to estimate supply requirements applying complex calculations, and Road, Air and Rail Movement Planners. EBB also provides staff officers with a large set of doctrinal documents in an electronic format. This paper provides an overview of the various tools of the Electronic Battle Box.

  19. 浮托顶推法架设64m钢桁梁技术%Technology of Erecting 64 m Span Steel Truss Girder with Float Tow and Jack - in Method

    Institute of Scientific and Technical Information of China (English)

    张云昭

    2011-01-01

    研究目的:浮托顶推法架设钢桁梁的施工设施主要由膺架、滑道、水上浮托支承、顶推纵移、方向及定位控制等五大系统组成.文章介绍了其工艺原理、工艺流程、操作步骤和主要安全质量措施,对修建同类桥梁具有重要的指导意义和借鉴意义.研究结论:浮托顶推法架设钢桁梁是在一般浮拖法架梁基础上的创新,它与一般浮拖法架梁的主要区别是钢梁纵移的动力不同,即采用钢桁梁后端的顶推装置代替前方的牵引设备,具有设备简单、操作方便、速度均匀、运行平稳、有利安全的特点.%Research purposes: Erecting the steel truss girder with the float tow and jack -in method needs five systems of the corbelling, slideway , bearing of uplift force, longitudinal movement by jack - in, and direction and position controller. This paper introduces the main technique principle, the technological process, operation steps and the measures of ensuring safety and quality of erecting the steel truss girder with the float toe and jack - in method for providing the reference to construction of similar bridge.Research conclusions:The float tow and jack -in method is the innovation based on the traditional float toe method. It is different from the traditional float toe method in the power to make the girder longitudinal moving. Namely, it uses the jack -in device at the rear end of steel truss to substitute the traction device in the front of the steel truss, with the features of using simply equipments, easy operation, even velocity, smooth running and ensuring the security.

  20. Spatial Mechanical Properties Analysis of Segment No. 0 of Long Span High Speed Railway Pre-stressed Concrete Continued Rigid Frame Bridge%大跨高速铁路连续刚构桥0号块空间力学特性分析

    Institute of Scientific and Technical Information of China (English)

    赵大亮; 苏国明; 王志贤

    2012-01-01

    以某大跨高铁连续刚构桥为研究对象,利用有限元程序ANSYS建立了该桥桥墩0号块的空间有限元计算模型,分析了0号块成桥运营阶段横截面的应力分布规律。结果表明,该桥桥墩0号块各部位均满足规范要求,位于横隔板处的截面,其翼缘板端部应力集中和剪力滞后现象较严重。计算结果已为该桥设计提供了依据,对同类桥梁0号块设计具有参考价值。%Taking a long bridge as an example in the paper, the finite element analysis program ANSYS is applied to estab- lish a three-dimensional solid finite element computational model of segment No. 0, the laws of stress distribution in the cross sections of the box girders are analyzed under operation stage. The results show that the stress of segment No. 0 are in good agreement with the current codes except the manhole part of the diaphragm. The results have been used for the design of the bridge and can be of great benefit for the similar projects.

  1. Preformed beading and boxing appliance.

    Science.gov (United States)

    Reddy, J Sashi Deepth; Padmanabhan, T V; Veerareddy, Chandrika; Chandrasekhar, M; Narendra, R

    2013-03-01

    Conventional beading and boxing procedure is time consuming and involves application of heat that might distort green stick compound used for border molding. Earlier studies regarding beading and boxing methods have shown usage of various materials that were disposable and that cannot be recycled. To reduce the time consumed for beading and boxing procedure and to make this procedure cost-effective by using recyclable beading material, "Preformed boxing appliance" with moldable clay meant for beading the secondary impression was used. Secondary impression was supported by 3 studs provided on the floor of the boxing appliance. The cast was poured. The duration for the entire procedure was much less than the conventional procedure.

  2. 贵港市同济大桥自锚式悬索桥总体设计%Overall Design of Self-Anchored Suspension Bridge of Tongji Bridge in Guigang City

    Institute of Scientific and Technical Information of China (English)

    薛雄; 高宝峰

    2016-01-01

    The main bridge of the Tongji Bridge in Guigang City ,with span arrangement of (50+140+280+140+50) m ,is a self‐anchored suspension bridge that has a main span of 280 m and bridge deck width of 37 .5 m .The main suspended girders are the multiple cells single box steel structures ,erected by incremental launching method with maximum launching spans of 2 × 85 m .The two end spans adopt the prestressed concrete structures .The towers are lotus‐shaped sin‐gle‐column towers without cross beam above the deck .The tower looks like an H‐shaped frame structure in plan ,quite elegant aesthetically ,and the minimum stable and safe coefficient of the bridge structure is 6 .4 .The main cables are composed of prefabricated parallel steel wire strands , the standard tensile strength of the steel wires is no less than 1 670 MPa .The strength safety coef‐ficient of the main cable is 2 .71 ,greater than the prescribed 2 .5 ,which meet the code require‐ments .T he hanger cables and the cable clamps are linked by pin connection .T he main cable sad‐dles are fully‐cast structures ,between the saddle base and the saddle pedestal plate ,sliding friction sets are installed .%贵港市同济大桥主桥为主跨280 m的自锚式悬索桥,桥跨布置为(50+140+280+140+50) m ,桥面宽37.5 m。悬吊跨主梁为单箱多室钢箱梁,采用顶推法施工,最大顶推跨径2×85 m。两端锚跨采用预应力混凝土结构。桥塔采用独柱式“荷花”造型,桥面以上塔柱不设置横梁,横向呈“H”形框架结构,景观造型新颖美观,桥塔结构最小稳定安全系数6.4。主缆采用预制平行钢丝索股,钢丝抗拉强度标准值为1670MPa,主缆强度安全系数2.71大于2.5,满足规范要求;吊索及索夹为销接式结构,主索鞍为全铸式结构,鞍底与底座座板间设滑动摩擦副。

  3. Simulating the Effects of Surface Roughness on Reinforced Concrete T Beam Bridge under Single and Multiple Vehicles

    Directory of Open Access Journals (Sweden)

    Rahul Kalyankar

    2016-01-01

    Full Text Available This research focuses on the application of the spatial system of finite element modeling for the vehicle-bridge interaction on reinforced concrete US Girder Bridge in order to obtain the effect of surface roughness. Single vehicle and multiple vehicles on reinforced concrete T beam bridge were studied with variable surface roughness profiles. The effects of six different surface roughness profiles (very good, good, measured, average, poor, and very poor were investigated for vehicle-bridge interaction. The values of the Dynamic Amplification Factor (DAF were obtained for single and multiple vehicles on T Beam Bridge for different surface roughness profiles, along with the distances between the axles of heavy vehicle. It was observed that when the bridge has very good, good, measured, and average surface roughness, the DAF values for the single vehicle over the bridge were observed to be within acceptable limits specified by AASHTO. However, for the bridge with multiple vehicles only very good and measured surface roughness profiles showed a DAF and vehicle axle distances within the acceptable limits. From the current studies, it was observed that the spatial system showed reliable responses for predicting the behavior of the bridge under variable road surface roughness conditions and was reliable in vehicle axle detection, and therefore, it has a potential to be use for realistic simulations.

  4. Analysis of the hull girder vibration by dynamic stiffness matrix method

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ping; ZHAO De-you

    2006-01-01

    Dynamic stiffness matrix method is applied to compute vibration of hull girder in this paper.This method can not only simplify the computational model, but also get much higher frequencies and responses accurately. The analytical expressions of dynamic stiffness matrix of a Timoshenko beam for transverse vibration are presented in this paper. All effects of rotatory inertia and shear deformation are taken into account in the formulation. The resulting dynamic stiffness matrix combined with the Wittrick-Williams algorithm is used to compute natural frequencies and mode shapes of the 299,500 DWT VLCC, and then the vibrational responses are solved by the mode superposition method. The computational results are compared with those obtained from other approximate methods and experiment,and it indicates that the method is accurate and efficient.

  5. Time-Variant Reliability Analysis of FPSO Hull Girder Considering Corrosion Based on Statistics

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dao-kun; TANG Wen-yong; ZHANG Sheng-kun

    2007-01-01

    FPSO is a kind of important exploitation platform used in ocean oil and gas industry, which has the unique character of mooring at outsea for a long time. Since it can not be inspected and maintained thoroughly at dock like other kinds of ships, the reliability of FPSO hull girder during the whole service should be focused. Based on latest corrosion database and rational corrosion model, the ultimate strength of one FPSO is calculated under the conditions of slight, moderate and severe corrosion. The results not only provide the reliability under different corrosion conditions, but also do well for further inspection and maintenance research. The results provide necessary foundation for deciding inspection intervals and maintenance measures, which has practical sense to improve the general safety level of ocean engineering.

  6. New technological approach in reconstructing Hanshin expressway. Base isolation for continuous rigid frame bridge; Hanshin kosoku doro fukkyu deno aratana kokoromi. Rittai ramen kyokyaku kabu menshinkyo wo chushin to shite

    Energy Technology Data Exchange (ETDEWEB)

    Morikawa, H. [Kobe University, Kobe (Japan). Faculty of Engineering

    1996-09-15

    This paper presents new technological approach in reconstructing Hanshin expressway damaged by Hyogo-ken Nanbu earthquake. The expressway of Benten section was composed of 6 three-span continuous RC floor slab girders supported by RC single columns, and 2 simple girders. Among them, 3 girders fell and 5 girders were largely damaged. As the study result of various structures for reconstruction, the 19-span continuous steel plate deck rigid frame bridge was adopted which is supported by steel piers with plane aseismic base isolation structure first in the world. Static and dynamic analyses of 3-D model were carried out to evaluate structure characteristics. The result of static analysis revealed that pile reaction forces are allowable, and horizontal forces due to earthquake or temperature at the bottom of piers considerably decrease. The result of eigenvalue analysis revealed that all of preferential lower- order modes are horizontal mode, and their frequencies are as low as 0.7Hz. The designed damping factor of aseismic bearings was estimated to be 15% or more. 9 figs., 1 tab.

  7. Aerodynamic stability of long span suspension bridges with low torsional natural frequencies

    DEFF Research Database (Denmark)

    Andersen, Michael Styrk; Johansson, Jens; Brandt, Anders

    2016-01-01

    Classical flutter of suspended bridge decks can be avoided if the torsional frequencies are lower than the vertical. Wind tunnel tests of single boxes and twin box section models with torsional natural frequencies above and below the vertical frequency has been conducted. Flutter was avoided in all....... In order to design aerodynamically stable suspension bridges with low torsional natural frequencies it is suggested to increase the mass moment of inertia and provide adequate torsional stiffness by the main cables spacing....

  8. Aerodynamic stability of long span suspension bridges with low torsional natural frequencies

    DEFF Research Database (Denmark)

    Andersen, Michael Styrk; Johansson, Jens; Brandt, Anders;

    2016-01-01

    Classical flutter of suspended bridge decks can be avoided if the torsional frequencies are lower than the vertical. Wind tunnel tests of single boxes and twin box section models with torsional natural frequencies above and below the vertical frequency has been conducted. Flutter was avoided in a....... In order to design aerodynamically stable suspension bridges with low torsional natural frequencies it is suggested to increase the mass moment of inertia and provide adequate torsional stiffness by the main cables spacing....

  9. Multi-scale investigation of tensile creep of ultra-high performance concrete for bridge applications

    Science.gov (United States)

    Garas Yanni, Victor Youssef

    Ultra-high performance concrete (UHPC) is relatively a new generation of concretes optimized at the nano and micro-scales to provide superior mechanical and durability properties compared to conventional and high performance concretes. Improvements in UHPC are achieved through: limiting the water-to-cementitious materials ratio (i.e., w/cm ≤ 0.20), optimizing particle packing, eliminating coarse aggregate, using specialized materials, and implementing high temperature and high pressure curing regimes. In addition, and randomly dispersed and short fibers are typically added to enhance the material's tensile and flexural strength, ductility, and toughness. There is a specific interest in using UHPC for precast prestressed bridge girders because it has the potential to reduce maintenance costs associated with steel and conventional concrete girders, replace functionally obsolete or structurally deficient steel girders without increasing the weight or the depth of the girder, and increase bridge durability to between 75 and 100 years. UHPC girder construction differs from that of conventional reinforced concrete in that UHPC may not need transverse reinforcement due to the high tensile and shear strengths of the material. Before bridge designers specify such girders without using shear reinforcement, the long-term tensile performance of the material must be characterized. This multi-scale study provided new data and understanding of the long-term tensile performance of UHPC by assessing the effect of thermal treatment, fiber content, and stress level on the tensile creep in a large-scale study, and by characterizing the fiber-cementitious matrix interface at different curing regimes through nanoindentation and scanning electron microscopy (SEM) in a nano/micro-scale study. Tensile creep of UHPC was more sensitive to investigated parameters than tensile strength. Thermal treatment decreased tensile creep by about 60% after 1 year. Results suggested the possibility of

  10. 青弋江某特大桥箱梁零号块水化热温度场分析%Study on the hydration heat and temperature field in zero block of QingYi River Bridge

    Institute of Scientific and Technical Information of China (English)

    陈志清; 刘荣桂; 蔡东升; 谢桂华

    2015-01-01

    通过有限元软件对青弋江某特大桥单箱三室预应力混凝土零号块箱梁进行水化热研究,根据现场记录的各测点的温度值与数值模拟结果对比分析,研究了预应力混凝土零号块箱梁在分层浇筑过程中温度变化和应力变化规律。结果表明:板越厚,温度越高,温度下降越缓慢;应力发生最大的部位位于横隔板与腹板的交界表面处、人洞表面处,对于分层浇筑,新旧混凝土处的横隔板与腹板的交界处是混凝土比较容易开裂的部位,横隔板与腹板交界表面处先受拉再受压,底板应力先受压后受拉。因此可以通过加强养护、布置温度钢筋等措施来改善混凝土内部的受力性能,为类似的工程提供参考。%The study of the hydration heat of the block zero of prestressed concrete box girder with a single box and triple cells of Qingyi River Bridge was done based on the finite element software. Base on temperature and numerical simulation results of field record-ing of each measuring point,the temperature change and stress variation of prestressed concrete box girder in a hierarchical block zero in the course of casting were analyzed. The results show that the thicker the board,the higher the temperature and more the temperature drops,the maximum stress occurs at the cross-junction of the surface of the separator and the web,also the surface of the people′hole. For the hierarchical placement,it is the old concrete crossbeam junction with the web that is easy to crack,crossbeam and web in-terface surface is under firstly tension and then bears pressure while the plate stress bears compression at first and then tension. There-fore,by strengthening the conservation,furnished temperature steel and other measures to improve the mechanical properties of con-crete. It can provide a reference for similar projects.

  11. Projection optics box

    Science.gov (United States)

    Hale, Layton C.; Malsbury, Terry; Hudyma, Russell M.; Parker, John M.

    2000-01-01

    A projection optics box or assembly for use in an optical assembly, such as in an extreme ultraviolet lithography (EUVL) system using 10-14 nm soft x-ray photons. The projection optics box utilizes a plurality of highly reflective optics or mirrors, each mounted on a precision actuator, and which reflects an optical image, such as from a mask, in the EUVL system onto a point of use, such as a target or silicon wafer, the mask, for example, receiving an optical signal from a source assembly, such as a developed from laser system, via a series of highly reflective mirrors of the EUVL system. The plurality of highly reflective optics or mirrors are mounted in a housing assembly comprised of a series of bulkheads having wall members secured together to form a unit construction of maximum rigidity. Due to the precision actuators, the mirrors must be positioned precisely and remotely in tip, tilt, and piston (three degrees of freedom), while also providing exact constraint.

  12. Dynamic analysis and modal test of long-span cable-stayed bridge based on ambient excitation

    Institute of Scientific and Technical Information of China (English)

    CHEN Chang-song; YAN Dong-huang

    2007-01-01

    To study the stifilless distilbution of girder and the method to identify modal parameters of cable-stayed bridge, a simplified dynamical finite element method model named three beams model was established for the girder with double ribs.Based on the simplified model four stiffness formulae were deduced according to Hamilton principle.These formulae reflect well the contribution of the flexural, shearing, free torsion and restricted torsion deformation, respectively.An identification method about modal parameters was put forward by combining method of peak value and power spectral density according to modal test under ambient excitation.The dynamic finite element method analysis and modal test were carried out in a long-span concrete cable-stayed bridge.The results show that the errors of frequencies between theoretical analysis and test results are less than 10%mostly,and the most important modal parameters for cable-stayed bridge are determined to be the longitudinal floating mode, the first vertical flexural mode and the first torsional mode, which demonstrate that the method of stifiness distribution for three beams model is accurate and method to identify modal parameters is effective under ambient excitation modal test.

  13. Near-fault directivity pulse-like ground motion effect on high-speed railway bridge

    Institute of Scientific and Technical Information of China (English)

    陈令坤; 张楠; 蒋丽忠; 曾志平; 陈格威; 国巍

    2014-01-01

    The vehicle-track-bridge (VTB) element was used to investigate how a high-speed railway bridge reacted when it was subjected to near-fault directivity pulse-like ground motions. Based on the PEER NAG Strong Ground Motion Database, the spatial analysis model of a vehicle-bridge system was developed, the VTB element was derived to simulate the interaction of train and bridge, and the elasto-plastic seismic responses of the bridge were calculated. The calculation results show that girder and pier top displacement, and bending moment of the pier base increase subjected to near-fault directivity pulse-like ground motion compared to far-field earthquakes, and the greater deformation responses in near-fault shaking are associated with fewer reversed cycles of loading. The hysteretic characteristics of the pier subjected to a near-fault directivity pulse-like earthquake should be explicitly expressed as the bending moment-rotation relationship of the pier base, which is characterized by the centrally strengthened hysteretic cycles at some point of the loading time-history curve. The results show that there is an amplification of the vertical deflection in the girder’s mid-span owing to the high vertical ground motion. In light of these findings, the effect of the vertical ground motion should be used to adjust the unconservative amplification constant 2/3 of the vertical-to-horizontal peak ground motion ratio in the seismic design of bridge.

  14. Application study on the first cable-stayed bridge with CFRP cables in China

    Directory of Open Access Journals (Sweden)

    Kuihua Mei

    2015-08-01

    Full Text Available In order to push forward the development of CFRP cable-stayed bridge and accumulate experiences, the study on the application of the first cable-stayed bridge with CFRP cables in China was carried out. The design essentials of main components of the bridge were introduced and its integral performances, including static properties, dynamic properties and seismic response were analyzed using finite element method. A new bond-type anchorage was developed and the processes of fabricating and installing CFRP cables were elaborated. Based on the results of construction simulation, a tension scheme for bridge was propound. During constructing, the stresses and displacement of girder and pylon, as well as the forces and stresses of cables, were tested. The results indicate that all sections of the bridge could meet the requirements of the ultimate bearing capacity and normal service; the performance of the anchorage is good and the stresses in each cable system are similar; the tested values accord well with the calculated values. Further, creep deformation of the resin in anchorages under service load is not obvious. All these results demonstrate that the first application of CFRP cables in the cable-stayed bridge in China is successful.

  15. The Classroom Animal: Box Turtles.

    Science.gov (United States)

    Kramer, David C.

    1986-01-01

    Provides basic information on the anatomy, physiology, behaviors, and distribution patterns of the box turtle. Offers suggestions for the turtle's care and maintenance in a classroom environment. (ML)

  16. Boxing-related head injuries.

    Science.gov (United States)

    Jayarao, Mayur; Chin, Lawrence S; Cantu, Robert C

    2010-10-01

    Fatalities in boxing are most often due to traumatic brain injury that occurs in the ring. In the past 30 years, significant improvements in ringside and medical equipment, safety, and regulations have resulted in a dramatic reduction in the fatality rate. Nonetheless, the rate of boxing-related head injuries, particularly concussions, remains unknown, due in large part to its variability in clinical presentation. Furthermore, the significance of repeat concussions sustained when boxing is just now being understood. In this article, we identify the clinical manifestations, pathophysiology, and management of boxing-related head injuries, and discuss preventive strategies to reduce head injuries sustained by boxers.

  17. Optical measurement system applied to continuous displacement monitoring of long-span suspension bridges

    Science.gov (United States)

    Lages Martins, L.; Rebordão, J. M.; Ribeiro, A. S.

    2013-04-01

    This paper provides a general description of main issues related to the design of an optical measurement system applied to continuous displacement monitoring of long-span suspension bridges. The proposed system's architecture is presented and its main components - camera and active targets - are described in terms of geometrical and radiometric characteristics required for long distance measurement of the tridimensional displacement of the stiffness girder in the middle section of the bridge's central span. The intrinsic and extrinsic camera parameterization processes, which support the adopted measurement approach, are explained in a specific section. Since the designed measurement system is intended to perform continuous displacement monitoring in long distance observation framework, particular attention is given to environmental effects, namely, refraction, turbulence and sensor saturation phenomena, which can influence the displacement measurement accuracy. Finally, a measurement uncertainty method is discussed in order to provide a suitable solution for the determination of the accuracy related to the proposed measurement approach.

  18. 南京长江第四大桥工程建设及关键技术%The construction and key techniques of the Fourth Nanjing Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    武焕陵

    2013-01-01

      南京长江第四大桥是世界上首座主跨1418 m的三跨连续弹性支承体系钢箱加劲梁悬索桥,首次采用了弹性支承体系以及缆索的分布传力锚固系统,克服了复杂地质条件下超大“∞”形地下连续墙(以下简称地连墙)及超大规模沉井深基础的设计施工技术难题,提出了主缆缆索混编技术及富氩气体保护焊技术,采用了复合浇筑式沥青钢桥面铺装技术,运用综合技术手段严格控制大体积混凝土施工质量。本文从建设管理及关键技术创新方面进行了综述。%The Fourth Nanjing Yangtze River Bridge is the first suspension bridge of three-span steel box girder using continuity and flexible bearing system with a main span of 1 418 m,and makes use of the flexible bearing system and distributional force transmission system with main rope for the first time. It overcomes the deep foundation design and construction technical problems of oversized“∞”shape diaphragm wall and ultra-large well-sinking under complicated geological conditions,proposes the technologies of main rope mixed-knit and argon-rich gas shielded arc welding,and uses the pavement technique of compound gussasphalt at steel bridge deck. Additionally,it utilizes synthetical technique to control construction quality of bulk mass concrete. This text summarizes the construction management and key technical innovation.

  19. Grey Target Optimization of Waterproof Adhesive Material for Concrete Bridge Deck Pavement Based on Mechanical Analysis%基于力学分析的桥面铺装防水粘结层材料灰靶优选

    Institute of Scientific and Technical Information of China (English)

    于新; 李英涛; 刘云

    2012-01-01

    为了优选与混凝土箱梁桥防水粘结层实际受力状态相匹配的材料,以沪杭高速公路拓宽改建工程高架桥为例,采用有限元法建立了全桥模型,在分析刹车、超载、随机动荷载等因素对防水粘结层力学响应的基础上,利用灰靶理论优选室内实测典型防水粘结层的相关技术参数.研究结果表明:刹车超载使防水粘结层产生的剪应力大于由桥面不平度引起的防水粘结层剪应力,最大可达0.397 MPa;橡胶沥青和SBS改性沥青防水粘结层综合性能较优,可作为混凝土桥防水粘结层材料.%In order to select the optimal waterproof adhesive material that meets the stress needs of concrete box girder bridge deck pavement, taking the viaduct in widening project of the Shanghai-Hangzhou Expressway as an example, a composite structure model of the whole bridge was established using the finite element method, and the influence of braking, overloading, random dynamic loading on the mechanical response of the waterproof adhesive layer was analyzed. The technique parameters of some typical materials for waterproof adhesive layer were tested in lab, and then analyzed by the grey target theory. The result shows that braking plus overloading has a larger effect on the shear stress of adhesive layer than the random dynamic loading caused by bridge deck roughness, and may produce a maximum shear stress of 0. 397 MPa. The rubber asphalt and SBS modified asphalt both have good performance, and can be used as the material of waterproof adhesive layer.

  20. 对连续梁桥减隔震支座抗震性能的比较分析%Seismic Isolation Bearing On the Comparative Analysis of the Seismic Performance for Continuous Beam Bridge

    Institute of Scientific and Technical Information of China (English)

    史康; 全健; 王福敏; 耿波

    2014-01-01

    以厦漳跨海大桥北汊南引桥为依托,采用有限元非线性时程分析方法,比较分析了铅芯橡胶支座和盆式橡胶支座对高烈度地区大跨径连续箱梁桥的抗震影响。研究结果表明:铅芯橡胶支座增加了结构在地震作用下的振动周期和主梁梁端位移,减小了固定墩的受力。相比盆式橡胶支座,铅芯橡胶支座可以使主梁梁端位移增加20%~200%,固定墩内力减小36%~80%。说明铅芯橡胶支座能够通过增加主梁位移达到减小桥墩受力的效果,隔震效果明显。该研究成果可为同类型桥梁的抗震设计提供参考。%Based on north south approach spans of Xiamen -zhangzhou cross-sea bridge by using the finite element nonlinear a-nalysis method, the seismic impact is compared between lead -rubber bearing and pot rubber bearing on the long span box girder bridges in high-intensity areas .The results show that the lead -rubber bearing can increase the vibration period and displacement of main beam in earthquake , reduce the force of fixed piers .Compared with pot rubber bearing , adopting lead-rubber bearing can in-crease the end displacement of main grider by 20%to 200%, meanwhile decrease internal force for fixed piers by 36%to 80%.The isolation effect is obvious that lead -rubber bearings can reduce the pier force by increasing the displacement of main beam .The re-search results provide a reference for the same type of bridge seismic design .

  1. Polymers in Curved Boxes

    CERN Document Server

    Yaman, K; Solis, F J; Witten, T A

    1996-01-01

    We apply results derived in other contexts for the spectrum of the Laplace operator in curved geometries to the study of an ideal polymer chain confined to a spherical annulus in arbitrary space dimension D and conclude that the free energy compared to its value for an uncurved box of the same thickness and volume, is lower when $D < 3$, stays the same when $D = 3$, and is higher when lowers the effective bending elasticity of the walls, and might induce spontaneous symmetry breaking, i.e. bending. (Actually, the above mentioned results show that {\\em {any}} shell in $D = 3$ induces this effect, except for a spherical shell). We compute the contribution of this effect to the bending rigidities in the Helfrich free energy expression.

  2. ACSYS in a box

    CERN Document Server

    Briegel, C; Hendricks, B; King, C; Lackey, S; Neswold, R; Nicklaus, D; Patrick, J; Petrov, A; Rechenmacher, R; Schumann, C; Smedinghoff, J

    2012-01-01

    The Accelerator Control System at Fermilab has evolved to enable this relatively large control system to be encapsulated into a "box" such as a laptop. The goal was to provide a platform isolated from the "online" control system. This platform can be used internally for making major upgrades and modifications without impacting operations. It also provides a standalone environment for research and development including a turnkey control system for collaborators. Over time, the code base running on Scientific Linux has enabled all the salient features of the Fermilab's control system to be captured in an off-the-shelf laptop. The anticipated additional benefits of packaging the system include improved maintenance, reliability, documentation, and future enhancements.

  3. Three Nucleons in a Box

    CERN Document Server

    Luu, Thomas

    2008-01-01

    I calculate finite-volume effects for three identical spin-1/2 fermions in a box assuming short-ranged repulsive interactions of `natural size'. This analysis employs standard perturbation theory in powers of 1/L, where L^3 is the volume of the box. I give results for the ground states in the A_1, T_1, and E cubic representations.

  4. Cable Supported Bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...

  5. 安庆长江铁路大桥主墩在深水无覆盖层条件下的围堰定位技术%Positioning Techniques for Steel Cofferdam of Main Pier of Anqing Changjiang River Railway Bridge Under Condition of Deepwater and Geology Without Overburden

    Institute of Scientific and Technical Information of China (English)

    郑大超; 田继开

    2012-01-01

    安庆长江铁路大桥主桥为主跨580 m的多跨连续钢桁梁斜拉桥,该桥3号墩基础采用圆形双壁钢围堰施工,围堰定位采用无导向船重锚锚碇定位系统.针对3号墩基础深水无覆盖层地质条件下围堰施工,为实现围堰的精确定位,从钢筋混凝土梳齿锚、收锚平台及转向马口3个方面进行围堰锚碇定位系统研究.围堰部分锚碇采用钢筋混凝土梳齿锚取代铁锚,钢筋混凝土梳齿锚由混凝土实体、起吊座、锚座、梳齿组成;围堰部分边锚通过新型转向马口转向至前、后定位船收锚;锚绳转向采用新型马口结构.%The main bridge of Anqing Changjiang River Railway Bridge is a multi-span continuous steel truss girder cable-stayed bridge with a main span 580 m and the foundation for the Pier No. 3 of the bridge was constructed by the circular double-wall steel boxed cofferdam that was positioned by the heavy anchor anchorage system without utilizing the guiding barge. In the light of the construction of the cofferdam under the condition of deepwater and geology without o-verburden and to achieve the purpose of accurate positioning of the cofferdam, the positioning system for the cofferdam was systematically studied from three aspects of the reinforced concrete (RC) comb anchors, anchor weighing platform and steering fair leaders. According to the study, it was determined that for part of the anchors of the cofferdam, the iron anchors should be replaced with the RC comb anchors and a comb anchor of such type was composed of the concrete body, lifting base, anchor base and comb teeth. Part of the side anchors of the cofferdam were steered to the front and rear positioning barges via the new type of the steering fair leaders and were weighed on the barges there and for steering of the anchor ropes, the new type of the steering fair leaders were provided also.

  6. Aerodynamic interaction between road deck and rail deck of separate-type highway-railway bridges and its effect on train running performance%分离式公铁双层桥面相互气动干扰及对列车走行性的影响

    Institute of Scientific and Technical Information of China (English)

    李永乐; 姜孝伟; 苏洋; 李龙安; 廖海黎

    2016-01-01

    There exists aerodynamic interaction between road deck and rail deck of highway-railway bridges under cross wind.In order to investigate the effect of different height intervals between two decks on train running performance, a separate-type highway-railway concrete box girder bridge was taken as an engineering example.The numerical simulation with CFD and the coupled vibration analysis of a wind-vehicle-bridge system were performed to determine train aerodynamic characteristics and to obtain its dynamic response.The results showed that the height interval between two decks has a major influence on train aerodynamic characteristics and its dynamic response;reducing the height interval leads to increase in the train lift coefficient and its vertical acceleration,and the wheel load reduction ratio increases as well;the effect of height intervals between two decks should receive more attention when selecting the optimal height interval in the design of highway-railway bridges.%横向风作用下公铁两用双层桥的上、下桥面间存在相互的气动干扰,为研究公铁两用组合桥间隔高度对列车走行性的影响,针对某分离式公铁两用混凝土箱梁桥,采用计算流体动力学(CFD)数值模拟和风-车-桥耦合振动研究的方法,分析了上、下桥面间隔高度对列车气动特性和车辆动力响应的影响。分析结果表明,公铁两用组合桥间隔高度对列车的气动特性和动力响应影响显著,间隔高度减小,列车升力系数和竖向加速度显著增大,轮重减载率也随之增大。公铁两用组合桥的设计应考虑间隔高度对列车的影响,以选择合理的间隔高度。

  7. A Mueller bridge set for cryogenic temperature measurements

    DEFF Research Database (Denmark)

    Diamond, J.M.

    1966-01-01

    An a.c. Mueller bridge set for resistance thermometry at cryogenic temperature is described. A commercial tuned null detector is used at an operating frequency of 1025 c/s. The set includes a high stability oscillator, line reject filter, phase shifter, Q multiplier and selector box. The latter p...

  8. 南京四桥钢桥面铺装防水粘结层试验及施工工艺研究%Tests for Waterproof Binding Layer of Steel Bridge Deck Pavement of Fourth Nanjing Changjiang River Bridge and the Paving Technique

    Institute of Scientific and Technical Information of China (English)

    章登精; 朱华平; 潘友强

    2014-01-01

    T he Fourth Nanjing Changjiang River Bridge is a three-span continuous steel box girder suspension bridge with a main span of 1 418 m ,to which the composite poured asphalt steel deck pavement system has been used for the first time .The lower layer of the pavement is the 4 cm thick GA-13 poured asphalt concrete w hile the upper layer is the 3 .5 cm thick AC-13 high-elastic modified asphalt concrete ,and the binding layer between the lower layer and the steel deck plate a-dopts the solvent rubber asphalt .To investigate the performance of the binding layer ,the solvent rubber asphalt was checked by the pull-out test and shear test .The results indicate that the bind-ing layer of solvent rubber asphalt can better meet the anti-debonding damage requirements of the steel bridge deck pavement under constant temperatures ,but under the extreme low temperatures , the tensile strength of the binding layer should be checked .The binding layer is proved satisfying the anti-shear requirements .To direct the binding layer construction ,the testing of the surface handling technique for the steel bridge deck and that of the field construction technique of the bind-ing layer were carried out .According to the test results ,the targeted measures taken for ensuring the construction quality were proposed . The sandblasting of the steel bridge deck was set at Sa3 .0 .After the sandblasting of the steel bridge deck ,the waterproof binding layer was directly paved and there was no need to do the traditional zinc spraying or painting protection .The rational construction control parameters were determined through experimental study and trial section con-struction .%南京四桥为主跨1418 m的三跨连续钢箱梁悬索桥,在国内首次采用复合浇注式沥青钢桥面铺装体系,下层为4 cm厚GA -13浇注式沥青混凝土,上层为3.5 cm厚AC -13高弹改性沥青混凝土,下层与桥面钢板的粘结层采用溶剂型橡胶沥青。为了解粘结层性能,

  9. Implications of seismic pounding on the longitudinal response of multi-span bridges-an analytical perspective

    Institute of Scientific and Technical Information of China (English)

    Reginald DesRoches; Susendar Muthukumar

    2004-01-01

    Seismic pounding between adjacent frames in multiple-frame bridges and girder ends in multi-span simply supported bridges has been commonly observed in several recent earthquakes. The consequences of pounding include damage to piers, abutments, shear keys, bearings and restrainers, and possible collapse of deck spans. This paper investigates pounding in bridges from an analytical perspective. A simplified nonlinear model of a multiple-frame bridge is developed including the effects of inelastic frame action and nonlinear hinge behavior, to study the seismic response to longitudinal ground motion. Pounding is implemented using the contact force-based Kelvin model, as well as the momentum-based stereomechanical approach, Parameter studies are conducted to determine the effects of frame period ratio, column hysteretic behavior, energy dissipation during impact and near source ground motions on the pounding response of the bridge. The results indicate that pounding is most critical for highly out-of-phase frames and is not significant for frame period ratios greater than 0.7. Impact models without energy dissipation overestimate the displacement and acceleration amplifications due to impact, especially for elastic behavior of the frames. Representation of stiffness degradation in bridge columns is essential in capturing the accurate response of pounding frames subjected to far field ground motion. Finally, it is shown that strength degradation and pounding can result in significant damage to the stiffer frames of the bridge when subjected to large acceleration pulses from near field ground motion records.

  10. Construction Technique for Accurate Positioning of Large Steel Boxed Cofferdam Using Pulling and Berthing Pier System%大型钢吊箱拉靠墩系统精确定位施工技术

    Institute of Scientific and Technical Information of China (English)

    陈超华; 徐斯林; 穆清君

    2011-01-01

    The main bridge of Wuhan Erqi Changjiang River Bridge is a three-pylon composite girder cable-stayed bridge. The pile cap of pylon pier No. 3 of the bridge is located in deepwater and was constructed in dry environment in large steel boxed cofferdam. To resolve the problem of accurate positioning of the large cofferdam, the pulling and berthing pier system was used after comparison of the different positioning schemes. The pier system is composed of a pulling pier at the upstream side and a berthing pier at the downstream side, on the pulling pier, the main pulling cables and tie-down cables were set while on thg berthing pier, the crisscross pulling cables were set. The positioning anchors were cast into the river longitudinally along the bridge and the side anchoring cables were set. After construction preparation, the cofferdam was initially posi-tioned by the pulling and berthing pier system to make the cofferdam basically set in place in plan position. By using the side anchoring cables, pulling cables and by means of non-uniform pumping of water into the bulks of the cofferdam, the plan position, plan torsion, oscillation and perpendicularity of the cofferdam were adjusted and the plan offsetting of the cofferdam was brought to be within +12 mm, the torsional angle to be 58" and the inclination to be 1/3 000 so as to make the construction of the cofferdam meet the relevant requirements in the codes and eventually realize the accurate positioning of the cofferdam.%武汉二七长江大桥主桥为三塔结合梁斜拉桥,其3号墩位于深水中,采用钢吊箱实现承台干施工.为解决大型钢吊箱精确定位难题,经过方案比选,采用拉靠墩系统定位方案,该系统由上游拉墩和下游靠墩组成,拉墩设主拉缆和下拉缆,靠墩设交叉拉缆,顺桥向抛锚,设置边锚缆.施工准备后,利用拉靠墩系统进行钢吊箱初定位,使其平面位置基本就位;通过边锚缆系统、拉缆系统及夹壁舱不均衡灌

  11. Black Box QGP

    CERN Document Server

    Tawfik, A

    2006-01-01

    According to extensive ab initio calculations of lattice QCD, the very large energy density available in heavy-ion collisions at SPS and now at RHIC must be sufficient to generate quark-gluon plasma (QGP), a new state of matter in the form of plasma of free quarks and gluons. The new state of matter discovered at RHIC seems to be perfect fluid rather than free plasma. Its shear viscosity is assumed to be almost zero. In this work, I first considered the theoretical and phenomenological consequences of this discovery and finally asked questions about the nature of phase transition and properties of matter. It is important to answer these questions, otherwise QGP will remain a kind of black box; one sends a signal via new experiments or simulations or models and gets another one from it. I will show that some promising ideas have already been suggested a long time ago. I will also suggest a new phase diagram with separated deconfinement and freeze-out boundaries and a mixed state of thermal quark matter and bub...

  12. The Black Box QGP

    CERN Document Server

    Tawfik, A

    2006-01-01

    According to the extensive ab initio calculations of lattice QCD, the much large energy density available in the heavy-ion collisions at SPS and now at RHIC should be enough to create the quark-gluon plasma (QGP); a new state of matter in form plasma of free quarks and gluons. The new matter discovered at RHIC is a ''nearly perfect'' fluid rather than a plasma. The shear viscosity is too small. We should then ask about the theoretical and phenomenological consequences and why we simply assumed that the deconfined hadronic matter should be an ideal gas. Finally, I will address five questions; about the properties of the new phases at high temperatures and the orders of phase transitions. Before we clarify such questions, the QGP will remain a kind of black box. One sends a signal via new experiments or simulations and gets another one out if it. Then one try to explain what is going on. I will show that some promising ideas already have been suggested long time ago, but it seems that community didn't care. Is ...

  13. Safety Analysis of the Patch Load Resistance of Plate Girders: Influence of Model Error and Variability

    Directory of Open Access Journals (Sweden)

    Farzad Shahabian

    2013-12-01

    Full Text Available This study aims to undertake a statistical study to evaluate the accuracy of nine models that have been previously proposed for estimating the ultimate resistance of plate girders subjected to patch loading. For each model, mean errors and standard errors, as well as the probability of underestimating or overestimating patch load resistance, are estimated and the resultant values are compared one to another. Prior to that, the models are initially calibrated in order to improve interaction formulae using an experimental data set collected from the literature. The models are then analyzed by computing design factors associated with a target risk level (probability of exceedance. These models are compared one to another considering uncertainties existed in material and geometrical properties. The Monte Carlo simulation method is used to generate random variables. The statistical parameters of the calibrated models are calculated for various coefficients of variations regardless of their correlation with the random resistance variables. These probabilistic results are very useful for evaluating the stochastic sensitivity of the calibrated models.

  14. Increasing the Capacity of Existing Bridges by Using Unbonded Prestressing Technology: A Case Study

    Directory of Open Access Journals (Sweden)

    Antonino Recupero

    2014-01-01

    Full Text Available External posttensioning or unbonded prestressing was found to be a powerful tool for retrofitting and for increasing the life extension of existing structures. Since the 1950s, this technique of reinforcement was applied with success to bridge structures in many countries, and was found to provide an efficient and economic solution for a wide range of bridge types and conditions. Unbonded prestressing is defined as a system in which the post-tensioning tendons or bars are located outside the concrete cross-section and the prestressing forces are transmitted to the girder through the end anchorages, deviators, or saddles. In response to the demand for a faster and more efficient transportation system, there was a steady increase in the weight and volume of traffic throughout the world. Besides increases in legal vehicle loads, the overloading of vehicles is a common problem and it must also be considered when designing or assessing bridges. As a result, many bridges are now required to carry loads significantly greater than their original design loads; and their deck results still deteriorated by cracking of concrete, corrosion of rebars, snapping of tendons, and so forth. In the following, a case study about a railway bridge retrofitted by external posttensioning technique will be illustrated.

  15. Damage identification algorithms applied to numerical modal data from a bridge

    Energy Technology Data Exchange (ETDEWEB)

    Jauregui, D.V.; Farrar, C.R.

    1996-02-01

    This paper extends the work summarized in the accompanying paper {open_quotes}Comparison of Damage Identification Algorithms on Experimental Modal Data From A Bridge.{close_quotes} A finite element model of the continuous three-span portion of the I-40 bridges, which once crossed the Rio Grande in Albuquerque, NM, was constructed. Following the experimental modal analysis, the bridge tests are repeated analytically using benchmarked finite element models of the bridge. A combination of shell and beam elements form the bridge model. Damage was simulated by creating adjacent nodes and disconnecting the elements on either side of the crack. However, because of the discretization of the finite element models only the final three levels of damage were evaluated. In addition to the analytical simulation of the experiments, the girder crack was repositioned at other potential damage locations. Analytical modal parameters were extracted through signal processing techniques, similar to those used in the experimental investigation and subsequently fed into damage identification routines. These routines have been adapted from those presented at past IMAC conferences and are identical to the ones used in the experimental investigation reported in the accompanying paper. This study provides a direct comparison of the relative accuracy of these different damage identification methods when they are applied to a set of standard numerical problems. The numerical models allow a variety of damage scenarios to be studied once the models have been benchmarked against experimental data.

  16. Bridges in Complex Networks

    CERN Document Server

    Wu, Ang-Kun; Liu, Yang-Yu

    2016-01-01

    A bridge in a graph is an edge whose removal disconnects the graph and increases the number of connected components. We calculate the fraction of bridges in a wide range of real-world networks and their randomized counterparts. We find that real networks typically have more bridges than their completely randomized counterparts, but very similar fraction of bridges as their degree-preserving randomizations. We define a new edge centrality measure, called bridgeness, to differentiate the importance of a bridge in damaging a network. We find that certain real networks have very large average and variance of bridgeness compared to their degree-preserving randomizations and other real networks. Finally, we offer an analytical framework to calculate the bridge fraction and average bridgeness for uncorrelated random networks with arbitrary degree distributions.

  17. 高速铁路桥梁结构噪声的全频段预测研究(Ⅱ):试验验证%Prediction of Structure-borne Noises of High-speed Railway Bridges in Whole Frequency Bands(Part Ⅱ):Field Test Verification

    Institute of Scientific and Technical Information of China (English)

    张迅; 李小珍; 刘全民; 张志俊; 李亚东

    2013-01-01

    In the companion paper,a prediction method of structure-borne noises of high-speed railway bridges in whole frequency bands was put forward on the basis of the theories of the boundary element method(BEM)and statistical energy analysis(SEA) of train-track-bridge spatial coupling vibration and steady-state acoustic radiation. In this paper,a 32 m simply supported concrete box girder was selected for case study and field test results were compared with computed values to verify the reliability of the theoretical model. The analysis results indicate as follows; Structure-borne noises of the concrete box-girder appear mainly below 200 Hz and attenuate slowly in the direction perpendicular to the railway line;the maximum sound pressure level(SPL) lies in the the frequency band with the central frequency of 50 Hz,and it demonstrates the obvious tonal characteristic at some speeds ;acoustic resonance at extension joints appears in the frequency band with the central freuqueney of 315 Hz and at remarkable degrees,how.ever its attenuation rate is fast in the direction perpendicular to the railway line. When measures are taken to conduct noise abatement, it is better to start from the frequency with the maximum SPL,which would be more effective.%前1篇系列文章(《铁道学报》2013年第1期,作者:李小珍,等)基于车线-桥空间耦合振动和稳态声辐射的边界元法、统计能量法理论,提出高速铁路桥梁结构噪声的全频段预测方法.本文以32 m双线混凝土简支箱梁为例,将数值仿真分析与现场试验结果进行对比,验证理论模型的可靠性.分析结果表明:该箱梁的结构噪声主要出现在200 Hz以下,沿垂直于线路方向的传播较远;噪声峰值出现在中心频率50 Hz的频带,且在某些速度下具有明显的有调性;梁缝处的共鸣声较大,出现在中心频率315 Hz的频带,沿垂直于线路方向的衰减较快.进行降噪处理时,可优先从噪声峰值频率入手,降低峰

  18. Computing out of the Box

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Baidu unveils "box computing/’ which it hopes will lead to a number of innovations on the InternetBaidu, China’s most popular search engine, held its Technology Innovation Conference 2009 at the China World

  19. Design of Cofferdam for Non-Navigable Span Bridge of Hong Kong-Zhuhai-Macau Bridge over Shallow Water Area%港珠澳大桥浅水区非通航孔桥围堰设计

    Institute of Scientific and Technical Information of China (English)

    黄剑锋

    2015-01-01

    The non‐navigable span bridge of the Hong Kong‐Zhuhai‐Macao Bridge over the shallow water area is a 85‐m span continuous composite girder structure ,the foundations for the bridge are the steel pipe composite pile foundations and the pile caps and piers supported on the foundations are the precast structures .The foundations were constructed by the interlocked doub‐le‐wall steel boxed cofferdams with no internal bracings .A cofferdam is 17 .6 m long ,13 .4 m wide ,23 .2 m high and the thickness of the bulkhead of the cofferdam is 0 .75 m .The cofferdam was designed into a removable structure and in plan ,was divided into 8 segments which were inter‐connected by the combination way of tenon locks and bolts .The cofferdam is mainly made up of three parts of the lateral plates ,horizontal ring plates and vertical partition plates and joints .In accordance with the different force conditions of the cofferdam in the construction process ,4 load cases were considered in the design .The software MIDAS Civil 2006 and ANSYS were used to set up the finite element models for the different load cases and the displacement and stress of the cof‐ferdam and its base sealing structure were analyzed .The results of the analysis indicate that the values of the maximum displacement and stress of the cofferdam and the base sealing concrete structure under the different load cases are all less than those as specified in the codes and can meet the requirements ,proving that the force conditions of the cofferdam in the construction are safe and the cofferdam is structurally rational .%港珠澳大桥浅水区非通航孔桥为跨度85 m的连续组合梁结构,其基础采用钢管复合桩基和预制墩台结构,基础采用无内支撑结构的双壁锁口钢套箱围堰施工。围堰长17.6 m、宽13.4m、高23.2m,壁仓厚0.75m。围堰设计成可拆装式结构,平面分为8块,各分块之间采用榫头式锁口与螺栓组合的方式连接。

  20. Structural Behavior of a Long-Span Partially Earth-Anchored Cable-Stayed Bridge during Installation of a Key Segment by Thermal Prestressing

    Directory of Open Access Journals (Sweden)

    Sang-Hyo Kim

    2016-08-01

    Full Text Available This study investigated structural behavior of long-span partially earth-anchored cable-stayed bridges with a main span length of 810 m that use a new key segment closing method based on a thermal prestressing technique. A detailed construction sequence analysis matched with the free cantilever method (FCM was performed using a three-dimensional finite element (FE model of a partially earth-anchored cable-stayed bridge. The new method offers an effective way of connecting key segments by avoiding large movements resulting from the removal of the longitudinal restraint owing to the asymmetry of axial forces in the girders near the pylons. The new method develops new member forces through the process of heating the cantilever system before installing the key segment and cooling the system continuously after installing key segments. The resulting forces developed by the thermal process enhance the structural behavior of partially earth-anchored cable-stayed bridges owing to decreased axial forces in the girders.

  1. Plate forming and break down pizza box

    Science.gov (United States)

    Pantisano, Frank; Devine, Scott M.

    1992-01-01

    A standard corrugated paper pizza box is provided with slit cuts cut through the top panel of the pizza box in a shape to form four circular serving plates with a beveled raised edge and cross slit cuts through the bottom panel of the pizza box separating the box into four essentially equal portions for easy disposal.

  2. 30 CFR 57.12006 - Distribution boxes.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distribution boxes. 57.12006 Section 57.12006... and Underground § 57.12006 Distribution boxes. Distribution boxes shall be provided with a... deenergized, and the distribution box shall be labeled to show which circuit each device controls....

  3. Simplified Analytical Method for Optimized Initial Shape Analysis of Self-Anchored Suspension Bridges and Its Verification

    Directory of Open Access Journals (Sweden)

    Myung-Rag Jung

    2015-01-01

    Full Text Available A simplified analytical method providing accurate unstrained lengths of all structural elements is proposed to find the optimized initial state of self-anchored suspension bridges under dead loads. For this, equilibrium equations of the main girder and the main cable system are derived and solved by evaluating the self-weights of cable members using unstrained cable lengths and iteratively updating both the horizontal tension component and the vertical profile of the main cable. Furthermore, to demonstrate the validity of the simplified analytical method, the unstrained element length method (ULM is applied to suspension bridge models based on the unstressed lengths of both cable and frame members calculated from the analytical method. Through numerical examples, it is demonstrated that the proposed analytical method can indeed provide an optimized initial solution by showing that both the simplified method and the nonlinear FE procedure lead to practically identical initial configurations with only localized small bending moment distributions.

  4. Box graphs and resolutions I

    Directory of Open Access Journals (Sweden)

    Andreas P. Braun

    2016-04-01

    Full Text Available Box graphs succinctly and comprehensively characterize singular fibers of elliptic fibrations in codimension two and three, as well as flop transitions connecting these, in terms of representation theoretic data. We develop a framework that provides a systematic map between a box graph and a crepant algebraic resolution of the singular elliptic fibration, thus allowing an explicit construction of the fibers from a singular Weierstrass or Tate model. The key tool is what we call a fiber face diagram, which shows the relevant information of a (partial toric triangulation and allows the inclusion of more general algebraic blowups. We shown that each such diagram defines a sequence of weighted algebraic blowups, thus providing a realization of the fiber defined by the box graph in terms of an explicit resolution. We show this correspondence explicitly for the case of SU(5 by providing a map between box graphs and fiber faces, and thereby a sequence of algebraic resolutions of the Tate model, which realizes each of the box graphs.

  5. Box graphs and resolutions I

    Science.gov (United States)

    Braun, Andreas P.; Schäfer-Nameki, Sakura

    2016-04-01

    Box graphs succinctly and comprehensively characterize singular fibers of elliptic fibrations in codimension two and three, as well as flop transitions connecting these, in terms of representation theoretic data. We develop a framework that provides a systematic map between a box graph and a crepant algebraic resolution of the singular elliptic fibration, thus allowing an explicit construction of the fibers from a singular Weierstrass or Tate model. The key tool is what we call a fiber face diagram, which shows the relevant information of a (partial) toric triangulation and allows the inclusion of more general algebraic blowups. We shown that each such diagram defines a sequence of weighted algebraic blowups, thus providing a realization of the fiber defined by the box graph in terms of an explicit resolution. We show this correspondence explicitly for the case of SU (5) by providing a map between box graphs and fiber faces, and thereby a sequence of algebraic resolutions of the Tate model, which realizes each of the box graphs.

  6. First-aid boxes - Reminder

    CERN Multimedia

    GS Department

    2010-01-01

    With a view to ensuring optimum use of the first-aid boxes on the CERN site, we should like to remind you of various changes introduced in March 2009: The TSO of the buildings concerned is responsible for the first-aid boxes, including checking their contents.   First-aid boxes may be restocked ONLY at the CERN stores (SCEM No. 54.99.80). This is no longer possible at the Infirmary. The associated cost is charged to the Departments.   First-aid boxes should be used only for mild injuries. All other cases should be referred to the Medical Service Infirmary (Bldg. 57 – ground-floor, tel. 73802) between 8.00 a.m. and 5.30 p.m. or to the Fire and Rescue Service (tel. 74444). N.B.: This information does not apply to the red emergency first-aid boxes in the underground areas or to the emergency kits for use in the event of being splashed with hydrofluoric acid.

  7. Applied Research of Shaped Box Girder for Urban Grade Separation%城市立交异型箱梁应用研究

    Institute of Scientific and Technical Information of China (English)

    苑鹏宇

    2011-01-01

    以日前城市立交桥中常用的混凝土异形箱梁桥为背景,从结构分析方法、设计方法及建模等方面进行了详细介绍,并针对某工程实例,结合相应的空间计算理论进行分析,为该类型桥梁的设计和施工研究提供参考.

  8. Experimental test investigation on one continuous steel box girder footbridge%某连续钢箱梁人行桥的检测试验研究

    Institute of Scientific and Technical Information of China (English)

    何江燕; 张银华

    2006-01-01

    某连续梁人行桥,经过多年的运营该桥部分出现了一些病害.为检测该桥的承载能力以及使用性能,基于通用有限元程序软件对该桥进行理论计算,同时根据理论计算结果作为控制内力进行现场检测试验.试验结果表明该桥使用性能较好,承载能力满足有关规范的要求.

  9. 波形钢腹板PC箱梁人行桥结构设计%Structure Design of PC Box - Girder Footbridge with Corrugated Steel Webs

    Institute of Scientific and Technical Information of China (English)

    陈朦朦

    2005-01-01

    针对我国在建的波形钢腹板PC组合连续箱梁人行桥的主梁及波形钢腹板的结构设计,对结构设计参数合理取值进行了分析,指出了该类桥梁结构在施工中应注意的问题.

  10. 箱梁极限承载力破坏仿真分析%Simulation Analysis of Failure of Box Girder Under Ultimate Bearing Capacity

    Institute of Scientific and Technical Information of China (English)

    尹冠生; 刘晓伟; 张小慧

    2013-01-01

    以J-H-C作为混凝土材料模型,以PLASTIC-KINEMATIC作为钢筋材料模型,用数值模拟箱梁在极限承载力下的破坏.实践证明,这两种材料模型能够较好地模拟箱梁在极限承载力下的破坏.

  11. Longitudinal force in continuously welded rail on long-span tied arch continuous bridge carrying multiple tracks

    Institute of Scientific and Technical Information of China (English)

    YAN Bin; DAI Gong-lian; GUO Wen-hua; XU Qing-yuan

    2015-01-01

    Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete composite section beam element to simulate concrete-filled steel tube (CFST) arch rib, using the beam element with rigid arm to simulate the prestressed concrete girder and using nonlinear bar element to simulate longitudinal constraint between track and bridge. Taking a (77+3×156.8+77) m tied arch continuous bridge with four tracks on the Harbin-Qiqihar Passenger Dedicated Line as an example, the arrangement of continuously welded rail (CWR) was explored. The longitudinal force in CWR on the tied arch continuous bridge, the pier top horizontal force and torque due to the unbalance load case, were analyzed under the action of temperature, vertical live load, train braking and wind load. Studies show that, it can significantly reduce track displacement to set the track expansion devices at main span arch springing on both sides; the track stress due to arch temperature variation can reach 40.8 MPa; the track stress, pier top horizontal force and torque are related to the number of loaded tracks and train running direction, and the bending force applied to unloaded track is close to the loaded track, while the braking force applied to unloaded track is 1/4 to 1/2 of the loaded track; the longitudinal force of track due to the wind load is up to 12.4 MPa, which should be considered.

  12. Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Taizhou Bridge lies between Taizhou, Zhenjiang and Changzhou City in Jiangsu Province. The total length of Taizhou Bridge is 62.088 kin. The whole line is designed by freeway codes with six lanes in two directions. The wholeinvestment is 9.37 billion RMB and the planned construction duration is 5.5 years. The main bridge crossing the Yangtze River is a continuous three-pylon two-span suspension bridge with the main span of 1 080 m. The bridge system is realized for the first time and ranks first in the world until now.

  13. 复杂异形桥梁风荷载参数数值风洞模拟%NUMERICAL WIND TUNNEL SIMUATION OF WIND LOADS PARAMETERS FOR A SPECIALLY SHAPED BRIDGE

    Institute of Scientific and Technical Information of China (English)

    林辉; 罗春晖

    2011-01-01

    Considering the uncertainty of wind load parameters for a specially shaped bridge, the Computational Fluid Dynamics method was applied to carry out the numerical wind tunnel simulation of wind load parameters on the main girder and the bridge tower. The influence of different air current attack angles on main girder structure under wind load and the influence of different air current wind age angles on bridge tower under wind load were investigated. The numerical calculation provided referential values of wind load parameters for the other similar specially shaped bridges.%针对复杂异形桥梁结构风荷载参数的不确定性问题,采用计算流体动力学方法,对主梁和桥塔的风荷载参数进行数值风洞模拟.研究了不同气流攻角对主梁结构风荷载的影响及不同气流风偏角对桥塔风荷载的影响.通过数值计算,为相似复杂异形桥梁风荷载参数取值提供了参考.

  14. Asymptotic Symmetries from finite boxes

    CERN Document Server

    Andrade, Tomas

    2015-01-01

    It is natural to regulate an infinite-sized system by imposing a boundary condition at finite distance, placing the system in a "box." This breaks symmetries, though the breaking is small when the box is large. One should thus be able to obtain the asymptotic symmetries of the infinite system by studying regulated systems. We provide concrete examples in the context of Einstein-Hilbert gravity (with negative or zero cosmological constant) by showing in 4 or more dimensions how the Anti-de Sitter and Poincar\\'e asymptotic symmetries can be extracted from gravity in a spherical box with Dirichlet boundary conditions. In 2+1 dimensions we obtain the full double-Virasoro algebra of asymptotic symmetries for AdS$_3$ and, correspondingly, the full Bondi-Metzner-Sachs (BMS) algebra for asymptotically flat space. In higher dimensions, a related approach may continue to be useful for constructing a good asymptotically flat phase space with BMS asymptotic symmetries.

  15. Identifying competencies of boxing coaches

    Directory of Open Access Journals (Sweden)

    Ioannis Tasiopoulos

    2014-10-01

    Full Text Available The purpose of this study was to find out the management skills required by boxing coaches to administrate their clubs. For the purposes of this study a scale was constructed which was answered by 98 boxing coaches. Explanatory factor analysis revealed seven factors: Communication-public relations (5 items, event management (4 items, management techniques (4 items, new technologies (4 items, prevention-safety (2 items, sport (5 items and sports facilities (2 items. The Cronbach of the scale was 0.85. The five competencies that rated by the coaches were: Supervisors of the area of training, maintaining excellent communication with athletes, using new technologies (e-mail, internet, handling disciplinary matters, accidents, complaints and reports on some sporting games and promoted harmony among athletes. We concluded that boxing coaches understand that the competencies required for meeting their obligations, were related to sports, prevention, safety and communications-public relations.

  16. 平大桥钢—混凝土结合段模型试验%Model Test of Steel and Concrete Joint Section of Dongping Bridge

    Institute of Scientific and Technical Information of China (English)

    占玉林; 赵人达; 毛学明; 董碧霞

    2011-01-01

    To study the whole process mechanical behavior of steel and concrete joint sections, in accordance with the actual Dongping Bridge and on the principle of equivalence, the model test of a steel and concrete joint section was designed and carried out. The scale of the model is 1:2. 5. The part of the concrete girder rib is the T-shape section and the transition at the joint section is the concrete-filled steel box cross beam. At the connection interface of the steel and concrete, the PBL shear connectors were used and the longitudinal prestressing tendons were arranged as well to join in the action of the shear connectors. In the model test, three stages of the static load, fatigue load and failure load were applied. The results of the test indicate that under the designed load, the joint section has good strength and rigidity and the stress levels are low. Under the fatigue load, microcracks appear in the surface of the concrete of the joint section, however, the global rigidity of the structure is still all right and relatively to the designed load, the failure load has rather high safety margin.%为研究钢-混凝土结合段全过程受力性能,结合东平大桥实桥,根据等效原则设计并完成了一榀钢-混凝土结合段模型试验.模型比例采用1∶2.5,混凝土梁肋部分为T形截面,结合段采用钢箱混凝土横梁过渡.钢与混凝土粘结界面采用PBL剪力连接件构造,并辅以纵向预应力筋共同作用.试验过程进行了静力、疲劳和破坏3个阶段的加载.试验结果表明:设计荷载作用下,结合段具有良好的强度和刚度,应力水平较低;疲劳荷载作用下,结合段的混凝土表层会有微小裂纹出现,但结构整体刚度依然良好;破坏荷载相对于设计荷载具有较高的安全储备.

  17. BOX: One Minute Volume 3

    OpenAIRE

    Butler, Rose

    2009-01-01

    BOX is a digital short originally developed in 2004 documented on a 1920’s box camera. This early moving image work formed the basis of a practice which interrogates our experience of moving image through the remediation of analogue technology with new media. In 2009 it was included in One Minute Volume 3; a programme of artists moving image curated by Kerry Baldry including work by: Tony Hill, Tina Keane, Katherine Meynell, Kayla Parker and Stuart Moore, Dave Griffiths, Marty St Jam...

  18. Black holes in a box

    Energy Technology Data Exchange (ETDEWEB)

    Witek, Helvi; Cardoso, Vitor; Nerozzi, Andrea [Centro Multidisciplinar de Astrofisica - CENTRA, Department de Fisica, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Gualtieri, Leonardo [Dipartimento di Fisica, Universita di Roma ' Sapienza' and Sezione INFN Roma1, P.A. Moro 5, 00185, Roma (Italy); Herdeiro, Carlos; Zilhao, Miguel [Centro de Fisica do Porto e Departamento de Fisica da Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Sperhake, Ulrich, E-mail: helvi.witek@ist.utl.p, E-mail: vitor.cardoso@ist.utl.p, E-mail: Leonardo.Gualtieri@roma1.infn.i, E-mail: crherdei@fc.up.p, E-mail: andrea.nerozzi@ist.utl.p, E-mail: sperhake@tapir.caltech.ed, E-mail: mzilhao@fc.up.p [California Institute of Technology, Pasadena, CA 91109 (United States)

    2010-05-01

    The evolution of BHs in 'confining boxes' is interesting for a number of reasons, particularly because it mimics some aspects of anti-de Sitter spacetimes. These admit no Cauchy surface and are a simple example of a non-globally hyperbolic spacetime. We are here interested in the potential role that boundary conditions play in the evolution of a BH system. For that, we imprison a binary BH in a box, at which boundary we set mirror-like boundary conditions.

  19. Structural Aspects of Railway Truss Bridges Affecting Transverse Shear Forces in Steel-Concrete Composite Decks

    Science.gov (United States)

    Siekierski, Wojciech

    2015-03-01

    At the steel-concrete interface, the horizontal shear forces that are transverse to cross beams occur due to joint action of the steel-concrete composite deck and the truss girders. Numerical analysis showed that values of the forces are big in comparison to the longitudinal shear forces. In both cases extreme force values occur near side edges of a slab. The paper studies possibilities of reduction of these shear forces by structural alterations of the following: rigidity of a concrete slab, arrangement of a wind bracing, arrangement of concrete slab expansion joints. An existing railway truss bridge span has been analysed. Numerical analysis shows that it is possible to reduce the values of shear forces transverse to cross beams. It may reach 20% near the side edges of slabs and 23% in the centre of slab width.

  20. Failure Load Test of a CFRP Strengthened Railway Bridge in Oumlrnskoumlldsvik, Sweden

    DEFF Research Database (Denmark)

    Täljsten, Björn; Bergström, Markus; Carolin, Anders

    2009-01-01

    steel reinforcement by approximately 10%, and increased the height of the compressed zone by 100 mm. When the shear failure occurred, the utilization of the compression concrete and CFRP rods were 100 and 87.5%, respectively. This indicates that a bending failure indeed was about to occur, even though......, Sweden is presented. In this particular test the shear capacity of the concrete girders was of primary interest. However, for any reasonable placement of the load (a line load placed transverse to the track direction) a bending failure would occur. This problem was solved by strengthening for flexure...... using carbon fiber reinforced polymer (CFRP) rectangular rods epoxy bonded in sawed up slots, e.g., near surface mounted reinforcement. The strengthening was very successful and resulted in a desired shear failure when the bridge was loaded to failure. The load-carrying capacity in bending...

  1. A Comparative Study of White Box, Black Box and Grey Box Testing Techniques

    Directory of Open Access Journals (Sweden)

    Mohd. Ehmer Khan

    2012-06-01

    Full Text Available Software testing is the process to uncover requirement, design and coding errors in the program. It is used to identify the correctness, completeness, security and quality of software products against a specification. Software testing is the process used to measure the quality of developed computer software. It exhibits all mistakes, errors and flaws in the developed software. There are many approaches to software testing, but effective testing of complex product is essentially a process of investigation, not merely a matter of creating and following route procedure. It is not possible to find out all the errors in the program. This fundamental problem in testing thus throws an open question, as to what would be the strategy we should adopt for testing. In our paper, we have described and compared the three most prevalent and commonly used software testing techniques for detecting errors, they are: white box testing, black box testing and grey box testing.

  2. Research on Reinforcement Technology for Treating Earthquake Disaster of Bridge%桥梁震害加固技术研究

    Institute of Scientific and Technical Information of China (English)

    王丙堤

    2013-01-01

    Research purposes: After the