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Sample records for box girder bridges

  1. PARAMETRIC STUDY OF SKEW ANGLE ON BOX GIRDER BRIDGE DECK

    OpenAIRE

    Shrikant D. Bobade *, Dr. Valsson Varghese

    2016-01-01

    Box girder bridge deck, is the most common type of bridges in world and India, it consists of several Slab or girders. The span in the direction of the roadway and connected across their tops and bottoms by a thin continuous structural stab, the longitudinal box girders can be made of steel or concrete. The Simple supported single span concrete bridge deck is presented in present study. Skewed bridges are suitable in highway design when the geometry of straight bridges is not possible. The sk...

  2. 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.

  3. Stiffened flanges used in steel box girder bridges

    OpenAIRE

    Ferreira, Pedro; Virtuoso, Francisco

    2015-01-01

    This paper presents a design method for stiffened flanges used in steel box girder bridges based on a set of design curves that take into account all relevant parameters regarding the ultimate strength of stiffened flanges, including the real boundary conditions for the inplane displacements at the edges. These design curves were developed and calibrated based on the results obtained with nonlinear analysis using the semi-analytical and finite element methods and they were vali...

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

    OpenAIRE

    Suchart Limkatanyu; Kittisak Kuntiyawichai

    2007-01-01

    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 a...

  5. Comparative Research of Extra-large-span Cable-stayed Bridge with Steel Truss Girder and Steel Box Girder

    Directory of Open Access Journals (Sweden)

    Tan Manjiang

    2015-01-01

    Full Text Available To research structural performance of extra-large-span cable-stayed bridge under different section forms, with the engineering background of a 800m main-span cable-stayed bridge with steel truss girder, the cable-stayed bridge with steel box girder is designed according to the current bridge regulations when two bridges are designed in an ultimate state of the carrying capacity, so the maximum stress and minimum stress of the stress envelope diagram are substantially the same. A comprehensive comparison is given to two types of bridge on the aspect of static force, natural vibration frequency, stability, economic performance and so on. Analysis results provide future reference for the large-span cable-stayed bridge to select between the steel truss girder and the steel box girder.

  6. 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.

  7. The Influence of Shear Effects on the Deflections of Steel Box Girder Bridges

    Directory of Open Access Journals (Sweden)

    V. Křístek

    2000-01-01

    Full Text Available It is already well known that the shear lag phenomenon, generated by shear deformations in the flanges of box girders, can result in a very non-uniform distribution, across the flange width, of longitudinal normal stresses, and consequently can then influence girder deflections. The shear lag effects become even more pronounced in cases where flange width increases in relation to girder span. However, in box girders, where the cross-sectional area of webs usually represents a fraction of the total cross sectional area, also shear deformations of webs can significantly affect the magnitudes of girder deflections. Both these phenomena – the shear lag in the flanges and the shear deformations in the webs – become particularly manifest in box girders subjected to considerable shear forces. Such a situation occurs when a box girder bridge is under the action of usual deal and live loads.

  8. Comparative Research of Extra-large-span Cable-stayed Bridge with Steel Truss Girder and Steel Box Girder

    OpenAIRE

    Tan Manjiang; Bai Zhizhou; Chen Dewei

    2015-01-01

    To research structural performance of extra-large-span cable-stayed bridge under different section forms, with the engineering background of a 800m main-span cable-stayed bridge with steel truss girder, the cable-stayed bridge with steel box girder is designed according to the current bridge regulations when two bridges are designed in an ultimate state of the carrying capacity, so the maximum stress and minimum stress of the stress envelope diagram are substantially the same. A comprehensive...

  9. 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.

  10. 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.

  11. Design of steel box girder for Taizhou Yangtze River Highway Bridge

    Institute of Scientific and Technical Information of China (English)

    Ding Lei; Shan Hongwei; Zhou Qing; Zheng Benhui

    2011-01-01

    Taizhou Yangtze River Highway Bridge is the first three-pylon two-span suspension bridge in China. The maingirder adopts flat steamline steel closed box girder which has well wind-resistant capability and is technically mature besides beautiful appearance. Straight web plates of the steel box girder in longitudinal direction are proposed in order to ensure the integrity of the steel box girder, and to keep the stress of the steel box girder continuous in the middle pylon,as well as to reduce the gradient of the middle pylon columns. The cross section of the box girder has one box with three cells. Solid-web diaphragm plate with good integrity and high torsional stiffness is adopted. The lifting lugs are utilized in the anchors of suspender cable. In this paper, selection of the cross section of the steel box girder, the general structure design, local structure design and main structure calculation results of Taizhou Yangtze River Bridge are introduced emphatically.

  12. 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.

  13. Early-age Cracking Control for Diaphragm of Box Girder Bridge with Prestressing Force

    OpenAIRE

    Zonglin Wang; Guodong Li

    2013-01-01

    It presents the results on the early-age cracking control of diaphragm in long-span prestressed concrete box girder bridge with prestressing force. Based on the three-dimensional hydration heat temperature conduction theory and humidity diffusion theory, the early-age cracking mechanism of diaphragm was simulated by finite element model. Meanwhile, the cracking control techniques of prestressing force to prevent the early-age cracking for diaphragm is discussed. The cracking control tec...

  14. 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.

  15. 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.

  16. 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.

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

    OpenAIRE

    Zheheng Chen; Tong Guo; Shengyou Yan

    2015-01-01

    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...

  18. Assessment of seismic performance of skew reinforced concrete box girder bridges

    Science.gov (United States)

    Abdel-Mohti, Ahmed; Pekcan, Gokhan

    2013-12-01

    The seismic vulnerability of highway bridges remains an important problem and has received increased attention as a consequence of unprecedented damage observed during several major earthquakes. A significant number of research studies have examined the performance of skew bridges under service and seismic loads. The results of these studies are particularly sensitive to modeling assumptions in view of the interacting parameters. In the present study, three-dimensional improved beam-stick models of two-span highway bridges with skew angles varying from 0° to 60° are developed to investigate the seismic response characteristics of skew box girder bridges. The relative accuracy of beam-stick models is verified against counterpart finite element models. The effect of various parameters and conditions on the overall seismic response was examined such as skew angle, ground motion intensity, soil condition, abutment support conditions, bridge aspect ratio, and foundation-base conditions. The study shows that the improved beam-stick models can be used to conduct accurate nonlinear time history analysis of skew bridges. Skew angle and interacting parameters were found to have significant effect on the behavior of skewed highway bridges. Furthermore, the performance of shear keys may have a predominant effect on the overall seismic response of the skew bridges.

  19. 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.

  20. Wireless ultrasonic wavefield imaging via laser for hidden damage detection inside a steel box girder bridge

    International Nuclear Information System (INIS)

    This paper presents a wireless ultrasonic wavefield imaging (WUWI) technique for detecting hidden damage inside a steel box girder bridge. The proposed technique allows (1) complete wireless excitation of piezoelectric transducers and noncontact sensing of the corresponding responses using laser beams, (2) autonomous damage visualization without comparing against baseline data previously accumulated from the pristine condition of a target structure and (3) robust damage diagnosis even for real structures with complex structural geometries. First, a new WUWI hardware system was developed by integrating optoelectronic-based signal transmitting and receiving devices and a scanning laser Doppler vibrometer. Next, a damage visualization algorithm, self-referencing f-k filter (SRF), was introduced to isolate and visualize only crack-induced ultrasonic modes from measured ultrasonic wavefield images. Finally, the performance of the proposed technique was validated through hidden crack visualization at a decommissioned Ramp-G Bridge in South Korea. The experimental results reveal that the proposed technique instantaneously detects and successfully visualizes hidden cracks even in the complex structure of a real bridge. (paper)

  1. Wireless ultrasonic wavefield imaging via laser for hidden damage detection inside a steel box girder bridge

    Science.gov (United States)

    An, Yun-Kyu; Song, Homin; Sohn, Hoon

    2014-09-01

    This paper presents a wireless ultrasonic wavefield imaging (WUWI) technique for detecting hidden damage inside a steel box girder bridge. The proposed technique allows (1) complete wireless excitation of piezoelectric transducers and noncontact sensing of the corresponding responses using laser beams, (2) autonomous damage visualization without comparing against baseline data previously accumulated from the pristine condition of a target structure and (3) robust damage diagnosis even for real structures with complex structural geometries. First, a new WUWI hardware system was developed by integrating optoelectronic-based signal transmitting and receiving devices and a scanning laser Doppler vibrometer. Next, a damage visualization algorithm, self-referencing f-k filter (SRF), was introduced to isolate and visualize only crack-induced ultrasonic modes from measured ultrasonic wavefield images. Finally, the performance of the proposed technique was validated through hidden crack visualization at a decommissioned Ramp-G Bridge in South Korea. The experimental results reveal that the proposed technique instantaneously detects and successfully visualizes hidden cracks even in the complex structure of a real bridge.

  2. 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.

  3. 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.

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

    International Nuclear Information System (INIS)

    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

  5. 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. 

  6. 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

  7. Analysis of Grillage Method for Two-span 24-m Continuous Multi-chamber Irregular Box Girder Bridge%两跨24 m连续多室异型箱梁桥梁格法分析

    Institute of Scientific and Technical Information of China (English)

    钟国东

    2009-01-01

    该文通过对异型箱梁桥有限元模型的建立、输出数据的整理及分析,说明异型箱梁桥的空间分析方法,为类似桥梁的结构分析及设计提供了参考.%Through the establishment of finite element model for the irregular box girder bridge, and the sorting and analysis of the output data, the article explains the space analysis method of the irregular box girder bridge to provide the reference for the structural analysis and design of the similar bridges.

  8. 大跨度斜拉桥钢箱梁非对称安装技术%Asymmetric Mounting Technology for Steel Box Girder of Large - span Cable - stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    黄中华

    2012-01-01

    介绍了辽宁滨海公路辽河特大桥斜拉桥钢箱梁非对称悬臂安装技术,通过对本桥方案箱梁非对称悬臂安装方案—边跨钢梁高支架上直接滑移就位连接、主跨钢梁逐段悬臂安装的方案可行性研究与实施,为同类型桥梁施工提供了很好的借鉴作用。%Asymmetric cantilever - type mounting technology of steel box girder of cable - stayed bridge of Li- aohe Bridge across Liaoning Coastal Highway is introduced; through the feasibility study and implementation of asymmetric cantilever - type mounting scheme of steel box girder of the bridge - scheme of direct slip in place con- nection on high bracket of side - span steel girder and section by section cantilever - type mounting of main span steel girder, a good reference is provided for the bridge construction of the same type.

  9. 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

  10. 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.

  11. 基于WIM数据的上海长江大桥钢箱梁的寿命评估%Life Evaluation of Box Girder of Shanghai Yangtze River Bridge Based on WIM Data

    Institute of Scientific and Technical Information of China (English)

    廖霞霞; 胡明敏; 徐昊

    2014-01-01

    Evaluation of the box girder details of Shanghai Yangtze river can provide the basis for the bridge ’ s maintenance and repairment .The research result of “Fatigue stress spectrum study of the steel box girder of Shanghai Yangtze River Bridge ,based on the analysis of WIM data” was used to get all the details of the stress spectrum of steel box girder .Then according to BS 5400 the tenth part ,confirming S-N curve which can reflect the details quality of fatigue .Finally ,estimating the steel box girder’s life with the combination of the Miner fatigue cumulative damage rule .According to the result ,we can know that during the current oper-ating process ,the box girder details have small stress amplitude ,high cycles and small damage magnitude . These details will not bring about fatigue damage .During the current operation ,the structure will keep high safety performance and reliability .Determine the damage point and the size of the damage value is unique in this article .%通过对上海长江大桥细节寿命的估算为大桥的维护和修复提供依据。基于论文“基于WIM数据的上海长江大桥钢箱梁应力谱研究”的研究结果,得到钢箱梁各细节的应力谱,同时参考英国桥梁规范BS 5400第十部分,确定了能够体现细节疲劳性能的 S-N曲线,并结合M iner疲劳累积损伤准则,对大桥钢箱梁细节寿命进行评估。研究结果表明,在现行日常运营过程中,钢箱梁各细节应力幅值较小,循环次数多,损伤量级很小,故细节不会发生疲劳破坏,即结构在现行运营期间保持了很高的安全性和可靠度。

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

    OpenAIRE

    So, Kevin K. L.; Moe M. S. Cheung; Zhang, Eric X. Q.

    2012-01-01

    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 ...

  13. 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 includi...

  14. Integrated Construction Technology of Fish-Belled Box Girder Bridge with Variable Cross-Section%鱼腹式变截面箱梁桥综合施工技术

    Institute of Scientific and Technical Information of China (English)

    孔德法

    2012-01-01

    鱼腹式变截面箱梁桥具有造型美观的特点,符合桥梁美学设计,但施工难度大;结合工程实例,通过建立空间直角坐标系,“从点到线、从线到面、从面到体”进行控制,思路清晰,工艺明确,较好的解决了变截面箱梁的施工难题.桥梁施工范围内淤泥深度为3.49~8.86 m,无明水,施工过程中,根据淤泥深度不同,分别采用“钻孔桩、贝雷梁”和“清淤换填、戗灰处理”两种方式对支架基础进行处理:经过施工检验,基础沉降量控制在允许范围内.%Fish-bellied box girder bridges with variable cross-section have attractive characteristics which comply with the idea of aesthetic design of bridge, but the construction is difficult. The author, in combination with actual project, established the space rectangular coordinate system to control the construction "from point to line, from line to surface, and from surface to body" with clear technological meanings and processes, therefore the construction puzzle of variable cross-section box girder was well solved. In addition, because the depth of silt within construction range is 3. 49 .8. 86 m without visible water, two ways of "bored piles plus bailey beam" and "dredging for filling, treating with ash" were adopted to deal with the support foundation during construction based on different depth of silt. The results of construction inspection show that the settlement of the foundation is within the allowed range.

  15. Experimentally Validated Nonlinear Analysis of Bridge Plate Girders with Deformations

    Directory of Open Access Journals (Sweden)

    Kużawa Mieszko

    2015-09-01

    Full Text Available Comprehensive methodology of numerical nonlinear analysis of the consecutive phases in the structural behaviour of bridge plate girders with deformations is presented. The analysis concerns all stages of structure loading until failure and especially determination of the ultimate shear load capacity. Verification and validation of the numerical procedures proposed is based on comparison of the calculated results with effects of experimental laboratory shear capacity tests of plate girders carried out at the University of Ljubljana.

  16. Joint design and model tests of extra-long-span continuous box girder bridge composed of UHPC%超大跨径UHPC连续箱梁桥接缝设计及模型试验

    Institute of Scientific and Technical Information of China (English)

    张策; 邵旭东; 张阳

    2015-01-01

    With the precast segment cantilever method,a bracket joint between segments is proposed for the extra-long-span continuous box girder bridge composed of ultra-high performance concrete (UHPC ). The optimization analysis is conducted based on some parameters,such as the horizontal angle of bracket joint,the ratio of joint tooth block depth and height,and the ratio of joint tooth block height to beam height. The optimal ones are less than 45 ,great than 1/10, and 1/3 ~ 2/3 correspondingly. A double cantilever box girder with bracket joint is designed according to the optimization results. Combining with model tests and numerical analysis,the shear behavior of web ’s joint and the influence of diaphragm plates on the joint performance are studied. The results demonstrate that the shear behavior of web’s joint is strong,and the shear capacity of joint can be increased by intensive diaphragm plates in thin-walled box girder. The cracking strain in joint’s corner is up to 455με,and the corresponding stress is about 9. 23MPa. The results are much greater than those of the ordinary concrete joint,and the resistance cracking degree of safety approaches 1. 63.%针对超大跨径UHPC连续箱梁桥,提出悬臂拼装法施工的牛腿式UHPC节段间接缝,并对其倾角、深高比、齿梁高之比进行优化设计,得到接缝牛腿最优水平倾角为0°~45°,深高比≥1/10,齿梁高比为1/3~2/3。利用优化结果设计制作一个双悬臂梁接缝模型,采用模型试验与数值分析相结合的方法,研究薄壁箱梁拼装节段腹板接缝的抗剪性能及横隔板对腹板接缝性能的影响。静力试验的结果与数值模拟分析的结果都表明:薄壁箱梁腹板接缝抗剪性能强,密集横隔板能提高接缝抗剪承载力,接缝角趾开裂应变达到455με,相应计算应力达14.71MPa,远大于普通混凝土的接缝强度,抗裂安全度可达1.63。

  17. 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...

  18. 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.

  19. 超大跨径单向预应力UHPC连续箱梁桥概念设计与初步实验%Conceptual design and preliminary experiment of super-long-span continuous box-girder bridge composed of one-way prestressed UHPC

    Institute of Scientific and Technical Information of China (English)

    邵旭东; 詹豪; 雷薇; 张哲

    2013-01-01

    A novel super-long-span continuous box-girder bridge made from ultra-high-performance concrete (UHPC) was proposed.By combining UHPC,thin-walled box girder with dense diaphragm plates and partial external prestressing into the novel box-girder system,a traditional three-dimensional prestressed structure is transformed into a longitudinal one-way prestressed one.Hence,not only can the main span length of girder bridges be improved,but also the ever existing problems in long-span PC bridges,such as the cracking in concrete girders and the excessive deflection at midspan,may be eliminated.A trial-design for a continuous box-girder bridge built from UHPC with main span length of 400m is presented,and the results show that the thicknesses of its components can be decreased greatly,the transverse stress decreased effectively by using the dense diaphragms,and the self-weight of superstructure may be reduced about 50% so that a good economy may be achieved and the one-way prestressed structure is completely feasible.The model tests were carried out to evaluate the creep deformation and shear capability of UHPC beam,and the results show that the creep deformation of UHPC beam is only 20% of that of ordinary concrete beam,and the shear capability of web can be further enhanced by employing dense diaphragms.The novel super-long-span continuous box-girder bridge is a competitive candidate in the aspects of safety,economy and durability,implying that it is applicable to the continuous girder bridge with main span length of 400m.%提出一种超大跨径超高性能混凝土(UHPC)连续箱梁桥新体系.新体系梁桥将超高性能混凝土(UHPC)、密集横隔板薄壁箱梁和部分体外预应力有机结合,变传统三向预应力为纵向单向预应力结构,不仅提升了梁桥跨径,而且可消除传统大跨径PC梁桥的主梁过度下挠和梁体开裂两类病害,通过对跨径400m的UHPC连续箱梁桥试设计,结果表明,新体系箱梁桥各种板件

  20. 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

  1. 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.

  2. Analysis of Load Test on Composite I-Girder Bridge

    OpenAIRE

    Huseynov, F.; Brownjohn, J. M. W.; O'Brien, Eugene J.; Hester, David

    2016-01-01

    This paper showcases the importance of field testing in efforts to deal with the deteriorating infrastructure. It demonstrates a load test performed on a healthy but aging composite reinforced concrete bridges in Exeter, UK. The bridge girders were instrumented with strain transducers and static strains were recorded while a four-axle, 32 tonne lorry remained stationary in a single lane. The results obtained from the field test were used to calculate transverse load distribution factors (DFs)...

  3. 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)

  4. 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.

  5. Performance of Bridge Decks and Girders with Lightweight Aggregate Concrete

    OpenAIRE

    Ramirez, J.A.; Olek, J.; Rolle, Eric Joseph; Manlone, Brian J.

    2000-01-01

    Structural lightweight concrete is a very versatile material and Haydite and Minergy lightweight aggregates can be utilized in the mixture development of concrete for use in girders and decks in bridges. More widespread use of lightweight aggregates (LWA) would result in savings in construction cost due to considerable dead load reduction. The materials phase of this research study evaluated the fresh concrete properties (slump, unit weight, and air content), the mechanical properties of ha...

  6. 福州市螺洲大桥主桥钢箱梁顶推施工技术%Fuzhou Beaufort Bridge Pushing steel box girder construction technology

    Institute of Scientific and Technical Information of China (English)

    黄强

    2011-01-01

    Bridge project with Fuzhou Beaufort introduced Pushing walker pan features and construction techniques of process equipment,and the use of centralized control system.At the same time according to the actual situation of this project,analysis of the top platform and push the design of temporary buttress will not rationality and economy.%结合福州市螺洲大桥工程介绍步履式平移顶推施工技术的特点和工艺设备,以及采用的集中控制系统。同时根据本工程实际情况,分析顶推平台与临时支墩的布置与设计的合理性以及经济性。

  7. Dynamic Magnification Factor in a Box-Shape Steel Girder

    Science.gov (United States)

    Rahbar-Ranji, A.

    2014-01-01

    The dynamic effect of moving loads on structures is treated as a dynamic magnification factor when resonant is not imminent. Studies have shown that the calculated magnification factors from field measurements could be higher than the values specified in design codes. It is the main aim of present paper to investigate the applicability and accuracy of a rule-based expression for calculation of dynamic magnification factor for lifting appliances used in marine industry. A steel box shape girder of a crane is considered and transient dynamic analysis using computer code ANSYS is implemented. Dynamic magnification factor is calculated for different loading conditions and compared with rule-based equation. The effects of lifting speeds, acceleration, damping ratio and position of cargo are examined. It is found that rule-based expression underestimate dynamic magnification factor.

  8. Influence of Traveling Wave Effect Based on Coefficient Reduction on Continuous Curve Box-girder Bridge%基于系数折减的行波效应对连续曲线箱梁桥的影响

    Institute of Scientific and Technical Information of China (English)

    吴多; 李青宁

    2014-01-01

    Traveling wave effect is a main influence factor for the multi-support excitation of large-span structures .It has been unable to meet the needs of engineering earthquake-resistance without considering the traveling wave effect of earth -quake ground-motion ,especially for the curve bridges by complex loading .Large mass model is currently used for the analysis of the traveling wave effect ,then the displacement differential method is used to calculate the relative displace-ment of the structure .However ,the displacement differential method often can lead to displacement “drift” and distortion for more support of large-span structures .Taking a five cross curve box girder bridge as an example ,a traveling wave processing method based on the basal coefficient reduction is proposed ,and the different apparent-wave velocity is used for seismic time-history response analysis .The results show that under the seismic action ,the traveling wave effect is fa-vorable for structural displacement ,and considering the traveling wave of reduction factor can better fix the actual dis -placement under the action of earthquake .Finally when considering the traveling wave effect ,the variable parameters such as the apparent-wave velocity and high pier have a greater influence on the seismic response of curve bridge .There-fore ,in the seismic analysis of curve bridge ,the specific requirements of engineering should be considered for contrast calculation so as to ensure the safety of the design .%行波效应是目前大跨结构中考虑多点激励的一种主要影响因素。特别是针对受力复杂的曲线桥,不考虑地震动的行波效应已经不能满足工程抗震的需求。目前常用大质量模型进行行波效应的分析,然后利用位移差动的方法求出结构的相对位移。对于多支撑的大跨结构来说位移差动的方法经常会导致位移的“漂移”和失真。以一座五跨曲线箱梁桥为例,提出了一种

  9. Study on Structural Forms of External Prestressing Anchorage for a Novel Continuous UHPC Box-girder Bridge%新型UHPC连续箱梁桥的体外预应力锚固构造形式研究

    Institute of Scientific and Technical Information of China (English)

    邵旭东; 张良; 张松涛; 欧阳泽卉

    2016-01-01

    针对新型UHPC连续箱梁桥的结构特点及预应力体系布置,对其腹板处体外预应力下折索进行齿块锚固研究。对独立矩形齿块进行应力分析,揭示板厚对锚固区壁板外侧“局部弯曲效应”的影响。通过拓扑优化分析构建出一个揭示齿块锚固区传力机理的简化平面杆系模型,提出两种齿块锚固区局部加强的方法。在此基础上,对UHPC箱梁桥的腹板体外预应力锚固齿块进行构造设计,对比6种不同锚固方案,分析横隔板、预应力筋齿块内转向和锚固长度对锚固区受力的影响,最终得出较为合理的体外预应力齿块锚固构造形式。%According to the characteristics of a novel continuous UHPC box-girder bridge and the lay-out of its prestressing system,the anchor block for external tendons on the web was studied.Firstly,the effect of the plate thickness on the“local bending effect”in anchorage zone was evaluated through the anal-ysis of stress in the isolated rectangular anchor block.A simplified plane linkage model was proposed through the topology optimization in order to study the force transfer mechanism in anchorage zone.More-over,two kinds of methods were developed to strengthen the anchorage zone based on the simplified mod-el.On the basis of the above research procedure,six different anchoring schemes of the anchor block for the external tendons were designed.After analyzing and comparing the performance of the different ancho-ring schemes,the effects of diaphragms,steering of prestressing tendons,and anchoring length of the an-chor block on the mechanical behavior of the anchorage zone were evaluated.Finally,a type of reasonable anchor block of the external tendons was obtained.

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

    DEFF Research Database (Denmark)

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

    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......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...

  11. 波形钢腹板连续箱梁剪滞效应引起的附加轴力分析%Additional Axial Force Analysis Caused by Shear lag Effect of Cintinuous Box-girder Bridge with Corrugated Steel Webs

    Institute of Scientific and Technical Information of China (English)

    吴焕庆; 张俊波; 刘世忠; 冀伟; 满自亭

    2013-01-01

    Under the condition of the plane section assumption and without considering the inertia moment of corrugated steel webs,this paper establishes the additional axial force formula for the two spans continuous box-girder bridge with corrugated steel webs based on a cubic parabola shear lag warping function.At the same time,it leads into the additional axial force stress ratio coefficient.Then it analyses the impact of additional axial stress to the influence degree of structural mechanical,which is based on the continuous box-girder bridge with corrugated steel webs under the full cross-uniformly distributed load and mid-span concentrated load.It shows that the value of additional axial stress can be ignored because the additional axial force stress ratio coefficient under the full cross-uniformly distributed load and the mid-span concentrated load is less than 1%.%基于平截面假定并不计波形钢腹板惯性矩,建立了波形钢腹板两跨连续箱梁在三次抛物线剪滞翘曲位移函数下的附加轴力计算式.引入附加轴向应力比系数,分析了波形钢腹板混凝土两跨连续梁在均布荷戢及跨中集中荷载作用下,附加轴向应力对结构受力性能的影响,分析表明:在两种荷栽工况下,附加轴向应力比系数均小于1%,可以忽略其效应.

  12. Shear evaluation of tapered bridge girder panels with steel corrugated webs near the supports of continuous bridges

    OpenAIRE

    Zevallos, E.; Hassanein, M.F.; Real Saladrigas, Esther; Mirambell Arrizabalaga, Enrique

    2016-01-01

    Because of public construction budgets were cut over the last few years, new bridge girders with corrugated webs to reduce the construction costs have become more widely studied and used. In spite that tapered bridge girders with corrugated webs (BGCWs) are used in modern bridges, their shear strength and behaviour rarely exists in literature. Based on available literature, the web of the linearly tapered BGCWs may be divided into three typologies with different structural response to shear f...

  13. Development of high performance precast/prestressed bridge girders

    Science.gov (United States)

    Akhnoukh, Amin K.

    Demand continues to increase for bridges with long spans and shallow depths. Due to safety concerns, four-span overpasses are being replaced with two span overpasses to avoid placement of piers near the highway shoulders. In the meantime, the bridge profile is restricted due to existing businesses nearby. Thus, nearly the same superstructure depth must be used for double the span length. This dissertation focuses on topics aiming at providing precast prestressed concrete girders with the shallowest possible depth for a given span. It forms parts of larger projects conducted by the University of Nebraska for the Nebraska Department of Roads and for the Wire Reinforcement Institute. Specifically, the following issues were researched: (1) Use of 0.7 in. diameter Grade 270 ksi strands for pretensioning of precast concrete girders at a strand spacing of 2 inches by 2 inches. This arrangement gives nearly 190 percent of the prestressing with 0.5 in. diameter strands and nearly 135 percent with 0.6 in. strands. The research focuses on the required confinement steel to allow determination of transfer and development lengths according to current procedures in the AASHTO LRFD Bridge Design Specifications for smaller strands. (2) Develop a self consolidating concrete (SCC) mix, using Nebraska aggregates that will allow for a specified design strength at service of 15 ksi and a minimum strength at one day of 10 ksi, representing the demand at the time of release of the prestress to the concrete member. Prior to this study, standard concrete strength prevailing in Nebraska has been 8 ksi at service and 6.5 ksi at release. It was the goal of the research to keep the cost of materials as low as possible but not exceeding 250 per cubic yard, compared to the proprietary mixes that cost approximately four times this amount. (3) Use of 80 ksi welded wire reinforcement (WWR) as the auxiliary reinforcement for shear, web end splitting and flange confinement. This would result in higher

  14. 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.

  15. Comparison of Stresses of Fatigue-sensitive Regions in Orthotropic Deck of Steel Box Girder for Highway and Railway Bridges%钢箱梁用于公、铁桥梁时正交异性板疲劳敏感部位应力比较

    Institute of Scientific and Technical Information of China (English)

    高立强; 蒲黔辉; 施洲

    2011-01-01

    The scheme of steel box girder used in the design of Yongjiang Railway Cable-stayed Bridge of Ningbo city is the first case in railway bridges in China. For railway bridges, the transverse position of steel rails is stable, and bridge deck pavement is different from that of highway bridges. In order to study the difference of orthotropic deck used in railway bridge and highway bridge, railway bridge and highway bridge deck pavements were installed on the deck separately. With the finite element method, the transverse and longitudinal influence lines of the stresses in the fatigue-sensitive regions with different bridge deck pavements were calculated. The reason why the stress in each fatigue-sensitive region was studied, and the characteristics of steel box girder orthotropic deck for railway bridge and highway bridge were analyzed. With the representative railway and highway vehicles as the loads, the stresses of steel box girder orthotropic deck in some fatigue-sensitive regions were calculated. The results of analysis and calculation show that (1 ) The dispersion of asphalt concrete deck pavement for highway bridge is weak, while that of railway bridge deck pavement is strong. Compared with highway bridge, the values of influence lines of the stresses in the fatigue-sensitive regions are smaller, and the lengths of influence lines are longer for railway bridge. (2) Under theload of normal railway vehicle, the largest stresses of rib-to-diaphragm joint and edge of cutout in diaphragm are similar to that under the load of normal highway vehicle. (3) In comparison with railway bridge, fatigue cracks are likely to emerge at the rib-to-deck joint for highway bridge orthotropic deck.%宁波甬江铁路斜拉桥在设计中采用钢箱梁方案,在铁路桥中为国内首例.铁路桥梁钢轨横向位置固定,桥面铺装也与公路桥梁不同,为研究钢箱粱正交异性板用于铁路桥梁和公路桥梁的区别,在桥面板上分别设置铁路与公路铺

  16. 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.

  17. The Viability of Steel-Concrete Composite Girder Bridges With continuous Profiled Steel Deck

    OpenAIRE

    Hatlee, Jonathan Russell

    2009-01-01

    The continuous permanent metal deck form system provides a quick and efficient method of constructing short-span, simply supported composite steel girder bridges. However, because shear studs can only be welded to the girder through the steel deck at rib locations, the number of shear stud locations is limited to the number of ribs in the shear span while the spacing of the shear studs is restricted to the rib spacing of the steel deck. This results in a condition where various...

  18. A EVALUATION OF THE EFFECTIVE PRESTRESS ON TIMBER CONCRETE COMPOSITE GIRDER BRIDGE

    Science.gov (United States)

    Araki, Shogo

    In applying the glulam timber to the large-sized structures, the new types of connections have been developed. In presence, there are a few joint systems using steel plates and bolts. However, those systems are not always adequately satisfied with durability. Therefore, the new joint system by prestressing was developed. In Nagano prefecture, the timber-concrete composite bridge was provided as the standard design of timber bridges, and the joint system is by prestressing. In case of concrete girder, work of prestress decrease by elastic strain, creep, and etc. However, timber-concrete composite girder is not cleared numerically. In this study, we discussed the effective prestress on timber-concrete composite girder based on time-dependent of prestress checked in existing bridge, and we suggest the evaluation method of it.

  19. Approach for analyzing the ultimate strength of concrete filled steel tubular arch bridges with stiffening girder

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-cheng; XIE Xu; ZHANG He; CHEN Heng-zhi

    2007-01-01

    A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate the stiffening girder and CFST arch rib. The geometric nonlinearity, material nonlinearity, influence of the construction process and the contribution of prestressing reinforcement are all taken into consideration. The accuracy of this method is validated by comparing its results with experimental results. Finally, the ultimate strength of an abnormal CFST arch bridge with stiffening girders isinvestigated and the effect of construction method is discussed. It is concluded that the construction process has little effect on the ultimate strength of the bridge.

  20. 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.

  1. 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.

  2. A numerical investigation on the fire response of a steel girder bridge

    OpenAIRE

    Paya-Zaforteza, I.; Garlock, Maria E.M.

    2012-01-01

    The response of bridges subject to fire is an under researched topic despite the number of bridge failures caused by fire. Since available data shows that steel girder bridges are especially vulnerable to fire, this paper delves into their fire response by analyzing with a 3D numerical model the response of a typical bridge of 12.20 m span length. A parametric study is performed considering: (1) two possibilities for the axial restraint of the bridge deck, (2) four types of structural steel f...

  3. Strain-Based Evaluation of a Steel Through-Girder Railroad Bridge

    OpenAIRE

    Daumueller, Andrew N.; David V. Jáuregui

    2012-01-01

    In the state of New Mexico (USA), passenger rail began in 2008 between Belen and Santa Fe on the Rail Runner, following the acquisition of about 100 miles of existing rail and related infrastructure. Many of the bridges on this route are over 100 years old and contain fatigue prone details. This study focuses on a steel through-girder bridge along this corridor. To accurately evaluate these structures for load carrying capacity and fatigue, an accurate analytical model is required. Accordingl...

  4. 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.

  5. 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.

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

    OpenAIRE

    Xiaoguang Deng; Muyu Liu

    2015-01-01

    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...

  7. Performance of Bridge Decks and Girders with Lightweight Aggregate Concrete, v. 2 of 2

    OpenAIRE

    Ramirez, J.A.; Olek, J.; Rolle, Eric Joseph; Malone, Brian Joseph

    2000-01-01

    Structural lightweight concrete is a very versatile material and Haydite and Minergy lightweight aggregates can be utilized in the mixture development of concrete for use in girders and decks in bridges. More widespread use of lightweight aggregates (LWA) would result in savings in construction cost due to considerable dead load reduction. The materials phase of this research study evaluated the fresh concrete properties (slump, unit weight, and air content), the mechanical properties of ...

  8. 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.

  9. Construction engineering of steel tub-girder bridge systems for skew effects

    Science.gov (United States)

    Jimenez Chong, Juan Manuel

    Closed structural sections, such as those having circular, rectangular or trapezoidal shape, possess high rotational rigidity when compared to open sections such as I-girders. The high torsional rigidity of closed sections makes them ideal for use in highly curved bridges. In this case, the geometry of the bridge results in large torsional forces. Because of structural efficiency and economy reasons, most of these closed-section bridges consist of a trapezoidal cross-section, with a top concrete slab and bottom and side steel plates. The slab is cast after the steel is erected and thus a system of internal diaphragms and braces is necessary to stabilize the system during erection. During the steel erection and the early stages of the concrete deck placement, the section can be considered as quasi-closed as the top concrete flange has not been cast or is not yet effective. During steel erection, undetermined and/or large torsional forces and/or displacements may result in fit-up problems requiring large stresses to overcome. During concrete deck placement, the undetermined displacements can affect the control of the deck thickness and the final deck geometry, such as the alignment of deck joints and the matching of stages in phased constructions projects. Due to the interactions between their various components, the behavior of curved and skewed tub-girder bridges is significantly more complex than that of straight bridges. When skewed supports are used in tub-girders, the interaction of the girder bending rotations and the displacement constraints induced by the skewed support diaphragms causes twisting of the girders at the supports. These twist rotations introduce additional torques into the system. Both curvature and skew can cause design and construction difficulties, especially at the supports, where the corresponding steel dead load deflections and the large torsional stiffness of the girders may lead to large fit-up forces. Currently, the general

  10. 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.

  11. 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.

  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...

  13. Strain-Based Evaluation of a Steel Through-Girder Railroad Bridge

    Directory of Open Access Journals (Sweden)

    Andrew N. Daumueller

    2012-01-01

    Full Text Available In the state of New Mexico (USA, passenger rail began in 2008 between Belen and Santa Fe on the Rail Runner, following the acquisition of about 100 miles of existing rail and related infrastructure. Many of the bridges on this route are over 100 years old and contain fatigue prone details. This study focuses on a steel through-girder bridge along this corridor. To accurately evaluate these structures for load carrying capacity and fatigue, an accurate analytical model is required. Accordingly, four models were developed to study the sensitivity of a bridge in New Mexico to floor-system connection fixity and the ballast. A diagnostic load test was also performed to evaluate the accuracy of the finite-element models at locations of maximum moments. Comparisons between the simulated and measured bridge response were made based on strain profiles, peak strains, and Palmgren-Miner’s sums. It was found that the models including the ballast were most accurate. In most cases, the pinned ended models were closer to the measured strains. The floor beams and girders were relatively insensitive to the ballast and end conditions of the floor-system members, whereas the stringers were sensitive to the modeling of the ballast.

  14. Evaluation of the Structure Stability of a Plate Girder Bridge Using MIDAS Structure Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eui Soo; Kim, Jong Hyuk [National Forensic Service, Wonju (Korea, Republic of)

    2014-04-15

    Recently, as a means of resolving the issue of legal liability in the event of an accident or a disaster, a wide variety of simulation techniques, such as structural and structure-fluid interaction analysis, have been used in the field of forensic engineering. The plate girder bridge discussed in this paper was being constructed between a pier and an abutment to expand an existing bridge, but an accident whereby the bridge overturned occurred at the end of the concrete laying process for a protective wall. This accident was caused by additional loads not being considered at the time of the design as well as the actual construction being different from the design. The additional loads ultimately generated a negative support force. In this study, we determined the cause of the accident by comparing the structural stability of the original design with that of the additional, non-conforming construction using MIDAS structural analysis.

  15. 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.

  16. 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)

  17. 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.

  18. COMPARATIVE ANALYSIS OF MODELS OF RAILWAY LOADS C14 AND LM71 FOR GIRDER BRIDGES

    Directory of Open Access Journals (Sweden)

    V. Artomov

    2014-01-01

    Full Text Available Purpose. The article analyzes the railway load LM71 for the purpose of its application in national design projects of the railway girder bridges. Purpose of the article is harmonization of national design codes of enginnering structures with the European standards (Eurocodes. Methodology. Analytical calculation methods (influence lines, the matrix analysis and computer programming are used in the article. Findings. Deflected mode parameters of the railway bridges under the influence of loads C14 and LM71 have certain differences. The extent of these differences depends on length, material of drift structures and also on dynamic coefficients. These dependences should be considered in national design codes and in harmonized with Eurocodes standards. In the further researches relationships between load C14 and models SW, HSLM taking into account various dynamic effects and trains speedis planned to determine. Originality. The presented results, in particular deflected mode parameters (including loads with dynamic coefficients, obtained for the first time. Practical value. Results of research are used in National Annex to the National Standard of Ukraine NSTU-N B EN 1991-2:2010. Eurocode 1. Actions on structures. Part 2. Traffic loads on bridges (EN 1991-2:2003.

  19. Case Study Evaluation of Steel Girder of Bridge Replacement by GFRP

    Directory of Open Access Journals (Sweden)

    Parinaz Arashnia

    2015-09-01

    Full Text Available Nowadays, because of the steel desired tensile, compressive strength, and light weight especially in the large spans, it has been widely popular in the bridge construction. On the other hand, there are some disadvantages including corrosion, buckling and weaknesses in the higher temperatures, and unsuitable weld which would be resolved using Fibres Reinforced Polymer (FRP profiles. The FRP is a remarkable class of composite polymers that can improve structural elements behaviours like as resistance against corrosion, fire, electricity, and magnetic fields. In this paper, composite GFRP & UHF beams along with the behaviour of I-shaped beam were studied and discussed under the point loads using numerical models, results were compared and verified with the experimental tests whereas two different beams were modelled and verified under static progressive loading performed with ABAQUS as an FEM base software. Finally, Moddares-Haqqani that is a steel girder bridge has been modeled by SAP software and maximum displacement has been determined. Then 4 GFRP beams modeled by ABAQUS software and best section has been determined. Beams are under dead and live loading. Purposes of this paper are evaluating of use of GFRP materials as a basic material in construction process and compare this operation with steel. Results shown that because of lower modulus of elasticity in GFRP compare with steel, displacement has increase in GFRP beams and hence beams dimension must be increase to limit displacement.

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

    OpenAIRE

    Chen Cheng; Kaiyin Zhang

    2011-01-01

    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 indic...

  1. Real-time damage monitoring scheme in PSC girder bridge using output-only acceleration data

    Science.gov (United States)

    Kim, Jeong-Tae; Park, Jae-Hyung; Do, Han-Sung; Lee, Jung-Mi

    2007-04-01

    Artificial neural networks (ANNs) have been increasingly utilized for structural health monitoring (SHM) due to the advantage that it needs only a few training data to detect damage in structures. In this study, a new damage monitoring method using a set of parallel ANNs and acceleration signals is developed for alarming locations of damage in PSC girder bridges. First, theoretical backgrounds are described. The problem addressed in this paper is defined as the stochastic process. In addition, a parallel ANN-algorithm using output-only acceleration responses is newly designed for damage detection in real time. The cross-covariance of two acceleration-signals measured at two different locations is selected as the feature representing the structural condition. Neural networks are trained for potential loading patterns and damage scenarios of the target structure for which its actual loadings are unknown. The feasibility of the proposed method is evaluated from numerical model tests on PSC beams for which accelerations were acquired before and after several damage cases.

  2. 体内-体外混合配束节段预制拼装箱梁足尺模型试验研究%Full scale model test of segmental precast concrete box girder with external and internal tendons

    Institute of Scientific and Technical Information of China (English)

    郑开启; 卜红旗; 刘钊; 惠卓; 吕志涛

    2013-01-01

    To investigate the structural behavior of segmental precast prestressed concrete box girder un-der the regular service stage and the construction state,a span of 48 m full scale box girder model of this type was tested for the Fourth Nanjing Yangtze River Bridge approach. The assembling and loading plans were de-termined according to the geometric parameters as well as the actual constraints of the girder. This paper focuses on the static performance,such as stress and displacement changes of the girder during segment loading and transporting. Comparative finite element method analysis was also performed for checking. The model test results show that at the regular service stage,the residual deformation of the girder after unloading is small,which demonstrates that the girder keeps in elastic during loading. The tooth joints of segments work well with each other and have no relative slip;the global performance of the girder is good as monotonous. The vertical distribution of longitudinal strain at joint and between joints basically accords with hypothesis of plane section. Also,the stress increment of prestress tendons is linear to the mid-span moment change. Finally,during the segment trans-port stage,it shows that there is sufficient compressive stress of the lower flange of the girder to meet the security requirements of transporting girder.%  以南京长江第四大桥引桥为背景,开展了一孔48 m跨径体内-体外混合配束节段预制拼装箱梁的足尺模型试验,以研究该类箱梁在正常使用阶段和施工状态下的结构行为。根据试验箱梁的尺寸参数以及实际约束条件确定了拼装与加载方案。本文重点研究正常使用荷载和梁上运梁两种工况下梁体应力状况与位移变化等结构静力性能,并与试验梁实体有限元模型进行对比分析。研究结果表明:在正常使用阶段,加、卸载后拼装梁体残余变形较小,基本处于弹性工作状态,整体

  3. Full scale model test of segmental precast concrete box girder with external and internal tendons%体内-体外混合配束节段预制拼装箱梁足尺模型试验研究

    Institute of Scientific and Technical Information of China (English)

    郑开启; 卜红旗; 刘钊; 惠卓; 吕志涛

    2013-01-01

    To investigate the structural behavior of segmental precast prestressed concrete box girder un-der the regular service stage and the construction state,a span of 48 m full scale box girder model of this type was tested for the Fourth Nanjing Yangtze River Bridge approach. The assembling and loading plans were de-termined according to the geometric parameters as well as the actual constraints of the girder. This paper focuses on the static performance,such as stress and displacement changes of the girder during segment loading and transporting. Comparative finite element method analysis was also performed for checking. The model test results show that at the regular service stage,the residual deformation of the girder after unloading is small,which demonstrates that the girder keeps in elastic during loading. The tooth joints of segments work well with each other and have no relative slip;the global performance of the girder is good as monotonous. The vertical distribution of longitudinal strain at joint and between joints basically accords with hypothesis of plane section. Also,the stress increment of prestress tendons is linear to the mid-span moment change. Finally,during the segment trans-port stage,it shows that there is sufficient compressive stress of the lower flange of the girder to meet the security requirements of transporting girder.%  以南京长江第四大桥引桥为背景,开展了一孔48 m跨径体内-体外混合配束节段预制拼装箱梁的足尺模型试验,以研究该类箱梁在正常使用阶段和施工状态下的结构行为。根据试验箱梁的尺寸参数以及实际约束条件确定了拼装与加载方案。本文重点研究正常使用荷载和梁上运梁两种工况下梁体应力状况与位移变化等结构静力性能,并与试验梁实体有限元模型进行对比分析。研究结果表明:在正常使用阶段,加、卸载后拼装梁体残余变形较小,基本处于弹性工作状态,整体

  4. Design of the Main Bridge Steel Truss Girder of Xinglong Bridge%兴隆大桥主桥钢桁梁设计

    Institute of Scientific and Technical Information of China (English)

    杨文; 何耀炜

    2016-01-01

    下承式钢桁梁桥因其具有建筑高度低、施工速度快和结构轻巧简洁等优点,成为中等跨度公路桥梁中有竞争力的桥型。文中以兴隆大桥为依托,建立数学分析模型,对下承式钢桁梁桥结构的受力特性进行分析,并指出该类型桥梁施工的方法和技术要点。%The through steel truss girder bridge becomes a bridge type for medium span highway bridg-es with low building height,fast construction speed and the advantages of compact and simple struc-ture.Based on the Xinglong Bridge,a mathematical analysis model is established in this paper to ana-lyze the mechanical characteristics of the steel truss girder bridge,and the method and technical points of the bridge construction are pointed out.

  5. 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。

  6. Plasticity Theory Analysis about the Bearing Section Limited Strength of Partial Filling Concrete Continuous Composite Girder Bridge%部分充填混凝土连续组合梁桥支座处截面极限强度的塑性理论分析

    Institute of Scientific and Technical Information of China (English)

    姬幸斌; 李文兴; 吴建明

    2012-01-01

      部分充填混凝土窄幅钢箱连续组合梁桥是钢箱-混凝土组合梁与矩形钢管混凝土结构结合的一种新型组合结构梁桥。基于一般钢箱-混凝土连续组合梁桥中支座负弯矩区因混凝土翼板开裂而导致抗弯强度、局部稳定性不足的特点,提出了一种部分充填混凝土窄幅钢箱连续组合梁桥,并对其中支座负弯矩区的正截面强度和支座截面抗剪性能进行了塑性理论分析。%  The narrow range of steel box continuous composite girder bridge that partially filled concrete is a new type of bridge which is composited by steel box-concrete composite girder and rectangular steel tube concrete. As the disadvantage that wing crack in negative moment region causing insufficient of bending strength and local stability of traditional steel box continuous composite girder bridge,a narrow range of steel box continuous composite girder bridge is presented. Then, the plasticity theory analysis is used on normal-section strength of bearing negative moment region and on cross-section support bearing shear performance.

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

    OpenAIRE

    Yue Zheng; Xiang Xiao; Lunhai Zhi; Guobo Wang

    2015-01-01

    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 abut...

  8. CFRP-Strengthening and Long-Term Performance of Fatigue Critical Welds of a Steel Box Girder

    Directory of Open Access Journals (Sweden)

    Roland E. Koller

    2014-02-01

    Full Text Available Empa’s research efforts in the 1990s provided evidence that a considerable increase of the fatigue strength of welded aluminum beams can be achieved by externally bonding pultruded carbon fiber reinforced polymer (CFRP laminates using rubber-toughened epoxies over the fatigue-weak welding zone on their tensile flange. The reinforcing effect obtained is determined by the stiffness of the unidirectional CFRP laminate which has twice the elastic modulus of aluminum. One can therefore easily follow that an unstressed CFRP laminate reinforcement of welded beams made of steel will not lead to a substantial increase in fatigue strength of the steel structure. This consideration led to the idea of prestressing an external reinforcement of the welded zone. The present investigation describes experimental studies to identify the adhesive system suitable for achieving high creep and fatigue strength of the prestressed CFRP patch. Experimental results (Wöhler-fields of shear-lap-specimens and welded steel beams reinforced with prestressed CFRP laminates are presented. The paper concludes by presenting a field application, the reinforcement of a steel pendulum by adhesively bonded prestressed CFRP laminates to the tensile flanges of the welded box girder. Inspections carried out periodically on this structure revealed neither prestress losses nor crack initiation after nine years of service.

  9. 钢-混组合箱梁的车桥耦合振动影响分析%Analysis on Coupling Reaction of Steel-Concrete Composed Box Girder Vibration

    Institute of Scientific and Technical Information of China (English)

    汪家正

    2011-01-01

    随着对于钢-混组合箱梁结构研究的深入开展,其在车辆荷载作用下的车桥振动响应问题也备受关注。不同截面形式对其车-桥相互作用性能有着较大影响。文章基于模态综合法的原理,建立两种不同截面形式的钢-混组合箱梁的动力计算模型,并对其动力特性进行了比较分析,结果表明:双车响应大致为单车响应的两倍,说明不同车辆荷载作用下桥梁的反应是线性的,为以后此类桥梁的设计提供参考。%As the development of study on steel-concrete composed box girder,its natural vibration under vehicle loading draws more and more attentions.Different types of cross sections have different influence on the interaction between vehicle and bridge.Based on the component mode synthesis principle,the article builds two different types of steel-concrete composed box girder model and performs comparison analysis on its dynamic property.The result shows that the coupling reactions for two vehicles are bigger than that for one vehicle.This indicates that the relationship between them is linear,which provides reference for future bridge design.

  10. Stress analysis of deck pavement of continuous steel box girder%连续钢箱梁桥面铺装层结构应力分析

    Institute of Scientific and Technical Information of China (English)

    李国芬; 曹牧; 王宏畅; 朱华平

    2013-01-01

      正交异性钢桥面的构造复杂,用理论算法对铺装层进行力学计算,较难得到精确的计算结果。本文利用有限元通用软件对曲线钢箱梁桥浇筑式沥青铺装层进行受力分析,将正交异性钢桥面板、铺装层作为整体,建立有限元模型,研究铺装层受力变形特点。根据钢桥面铺装层常出现的病害,并结合超载及刹车产生的水平荷载对铺装层受力的影响,提出相应的桥面铺装层破坏的综合控制指标。%The geometric structure of steel deck plates is complex. So it is difficult to get precise results in the mechanics calculation of deck pavement with traditional methods. This paper adopts the finite element meth-od for the mechanics analysis of the composite guss asphalt surfacing layer of curved steel box girder bridges. By taking the orthotropic steel deck and the pavement as a whole,a reasonable finite element model which estab-lished can be used to study the stress and deformation features of the surfacing layer. According to the common diseases in steel deck pavements and the effect of the overload and the horizontal load in braking to the pave-ment,this paper puts forward the comprehensive control indicators for pavement failures.

  11. 粉房湾长江大桥主桥钢桁梁架设施工技术%Construction Techniques for Erection of Steel Truss Girder of Main Bridge of Fenfangwan Changjiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    王存贵; 王殿永; 高杰; 靳春尚

    2012-01-01

    The main bridge of Fenfangwan Changjiang River Bridge in Chongqing City is a semi-floating system steel truss girder cable-stayed bridge with double pylons, double cable planes and with span arrangement (216. 5 + 464 + 216. 5) m. The main girder of the bridge is designed as the steel truss girder structure erected by the piece-by-piece assembling. In the light of the topographic conditions of the south and north banks, the asymmetric way of erection was chosen for the girder. The steel truss girder on the south bank side was erected from the side span towards the central span. The girder of the side span was assembled on the scaffolding, the girder in the middle was erected first and then the components like the edge stringers and edge deck plates were erected, using the deck truck cranes. The girder for the main span was erected by the cantilever assembling method. The girder of the north bank was erected by the balanced two-cantilever assembling method and the 5 blocks of the girder atop and on both sides of a main pier were assembled on the pier-side brackets.%重庆粉房湾长江大桥主桥为跨度(216.5+464+216.5)m的双塔双索面半飘浮体系钢桁梁斜拉桥,主梁采用钢桁梁结构.钢桁梁采取散拼架设,南、北岸钢桁梁根据地形情况选取了不对称的方式施工.南岸钢桁梁由边跨向中跨架设,边跨钢桁梁采用支架拼装,先架设中间桁架,再利用桥面汽车吊架设边纵梁、边桥面板等构件;主跨钢桁梁采用悬臂拼装.北岸钢桁梁采用双悬臂对称架设,主墩墩顶及两侧共5个节段钢桁梁采用墩旁托架拼装.

  12. 一种计入桥面铺装非完善接触效应的箱梁结构计算方法%Application of Deck Pavement into Box Girder Structure

    Institute of Scientific and Technical Information of China (English)

    董建兴

    2013-01-01

    The local simulation analysis is carried out for the imperfect contact between the bridge deck pavement and the box girder structure.Then the shear stiffness is obtained from load-slip curves.And a 3-D model for a real bridge structure is built and analyzed in which Spring elements are adopted to simulate the interface shear stiffness.By this calculation model the structural responses under some loads are acquired to explore the effect of considering interface slip between the concrete box deck and the pavement on the structural behavior of the bridge.The results indicate that the cracking load and ultimate bearing capacity of structure are advanced by the affect of the pavement.By comparing the data,the advice of analyzing the box girder with deck overlays is proposed,which has definite social and economic benefit.%采用有限元软件对桥面铺装与箱梁结构桥面板之间的非完善接触进行局部仿真分析,提取荷载一滑移曲线获得界面之间的剪切刚度,并在整体模型中用弹簧单元模拟界面之间的剪切刚度,对猫铺大桥结构进行三维空间分析.通过这种计算模式分析结构在荷载作用下的的整体响应,探讨比较了考虑混凝土与桥面铺装界面滑移对箱梁结构受力性能的影响.研究得出了考虑铺装层参与截面受力能提高结构开裂荷载和极限承载能力、增大结构刚度的结论.计算结果对考虑铺装层作用时箱梁计算提出合理建议,具有一定的经济和社会效益.

  13. Difference Solution for Shear Lag Effect of Twin-cell Box Girder%单箱双室箱梁剪力滞效应的差分解

    Institute of Scientific and Technical Information of China (English)

    刘勇; 张丽; 张元海; 张效军

    2012-01-01

    从满足剪力滞翘曲应力的轴向平衡条件出发,选取三次抛物线翘曲位移模式,考虑了悬臂板宽度及上下翼板至形心轴不同距离的影响,从而更合理反映箱形梁剪力滞翘曲应力.导出了剪力滞翘曲惯性矩、惯性积和面积等几何特性计算公式.根据最小势能原理,建立了薄壁箱梁挠曲剪力滞的控制微分方程.采用有限差分法推导出变截面悬臂葙梁剪力滞效应计算式和边界条件.运用Ansys有限元软件中的Shell63单元进行建模,分析单箱双室三跨连续箱梁剪力滞效应的分布规律.对比分析了翘曲位移模式及轴力平衡条件对剪力滞效应的影响.结果表明:二、三次抛物线均不是最合理的位移模式;连续箱梁的剪力滞效应受翘曲位移模式的影响很小;轴力平衡条件对应力分布的影响亦很小.%The warping displacement pattern of cubic parabolic curve is chosen on the axial force equilibrium condition. In order to reflect the stress distribution in the box girder more rationally,the width of the cantilever plate and the distance form the top and bottom flange plates to the centre axis are fully considered. Formulas of the moment of inertia, product of inertia and sectional area for shear lag warping geometrical properties are deduced. The equations of equilibrium with considering the shear lag for thin-walled box girders are established on the basis of the variation principle. The calculation formulas and bounding conditions of shear lag effect of the continuous box girder are deduced by adopting the finite difference solution. The Shell63 unit of Ansys program is used to analyze the distributions of shear lag effect for three-span continuous box girder. The influence of distributions by longitudinal warping displacement patterns and axial force equilibrium condition is analyzed. The results show that neither of the warping displacement patterns of quadratic nor cubic parabolic curve is the most

  14. 超宽箱梁抗裂混凝土配合比试验研究%Experimental Study of Mix Proportioning of Cracking Resistance Concrete for Very Wide Box Girder

    Institute of Scientific and Technical Information of China (English)

    王运金; 李北星; 唐凯; 胡峰强; 张剑峰

    2012-01-01

    为防止九江长江公路大桥主桥超宽箱梁混凝土的早期开裂,进行专门的抗裂混凝土配合比优化设计试验.通过水化热、绝热温升、平板法塑性收缩开裂、温度~应力试验机开裂等试验方法,研究了胶凝材料组成对混凝土早期抗裂性的影响,配制出抗裂性能良好的C55混凝土.该混凝土采用42.5级p·Ⅱ水泥掺入25%的Ⅰ级粉煤灰、缓凝型聚羧酸盐高性能减水剂配制,绝热温升55.8℃,塑性收缩抗裂等级Ⅱ级,开裂温度8.7℃,应力储备37.3%,实际应用效果良好.%To prevent the concrete for the very wide box girder of the main bridge of Jiujiang Changjiang River Highway Bridge from early stage cracking, the optimal design and experiment for the mix proportioning of cracking resistance concrete for the box girder was specially carried out. By way of the hydration heat testing, adiabatic temperature rise testing, flat slab testing of plastic shrinkage cracking and cracking testing of temperatures-stress testing machine, the influence of the cementitious material compositions on the early stage cracking resistance of the concrete was studied and the C55 concrete having good cracking resistance was accordingly prepared. The concrete is used with the Grade 42. 5 P?II cement added with 25% of the Grade I flyash and high-range water reducer of retarding-type polycarboxylate. The adiabatic temperature rise of the concrete is 55. 8 ?, the level of the plastic shrinkage cracking resistance is grade II, the cracking temperature is 8. 7 ? and the stress reserve is 37. 3%. The practical application of the concrete proves that the effect of the concrete is sound.

  15. Aerodynamic hysteresis of thin airfoil and streamline box girder under large amplitude oscillation%大振幅下薄翼和流线型箱梁的气动迟滞研究

    Institute of Scientific and Technical Information of China (English)

    王骑; 廖海黎; 李明水; 马存明

    2013-01-01

    回顾了机翼和箱梁的气动迟滞效应研究现状,介绍了大振幅下获取薄翼和流线型箱梁自激气动力的风洞试验.研究结果表明:薄翼在超过失速角的振幅条件下,升力并没有出现明显的失速现象,但气动力的高阶谐波分量显著增加;大振幅条件下,流线型箱梁的气动力高阶谐波分量也比较显著,并以第2和第3阶谐波分量为主.此外,在大振幅条件下,流线型箱梁的气动力矩迟滞曲线可出现“8字环”,即气动力在一个振动周期内既做了正功也做了负功;其中,迟滞曲线“8字环”的气动正功部分随着振幅和折算风速的增大而增加.该现象可导致桥梁也出现类似于失速机翼的极限环震荡.最后,基于不同振幅下流线型箱梁的力矩迟滞曲线,简要讨论了大跨度桥梁在颤振后状态可能出现的振动形式和气动稳定性.%The state-of-the-art of aerodynamic hysteresis of airfoil and box girder is reviewed briefly. A detailed introduction is given to the wind tunnel tests of motion-induced aerodynamic force measurements of thin airfoil and streamline box girder under large amplitude oscillation. The test results show that the lift stall didn't occur while the torsional amplitude exceeds the stall incidence angle, and the higher order harmonic components are remarkable in the aerodynamic force. The aerodynamic hysteresis curve of pitching moment for streamline box girder can take on "8-shape" loop, which means that the aerodynamic forces can provide both the positive and negative works within one vibration period. The limited cycle oscillation may also occur for bridge deck, which is usually observed in the stall airfoil. Based on the aerodynamic hysteresis curve of pitching moment under different amplitudes, the possible vibration pattern and aerodynamic instability are discussed for the post-flutter state of long span bridge.

  16. A concrete balanced cantilever box girder bridge in the Netherlands with carbon fibre prestressing cables

    NARCIS (Netherlands)

    Hordijk, D.A.; Bruggeling, A.S.G.; Kaptijn, N.

    1998-01-01

    In the Netherlands a pilot project has started to recognize the possibilities of non-metallic materials for prestressing. This project will also serve to gather more knowledge regarding the properties of non-metallic wires, their anchorages and their application in large tendons. It is intended to a

  17. 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.

  18. Analysis and Study of Force Conditions of Group Shear Studs of Long Span Steel and Concrete Composite Girder Bridge%大跨度钢—混组合梁桥剪力群钉受力分析研究

    Institute of Scientific and Technical Information of China (English)

    赵建; 郑舟军

    2013-01-01

    组合梁仿真分析时将多个剪力钉简化成一个等效剪力群钉进行模拟,不能准确得到每个剪力钉的受力情况.为解决此问题,根据实桥集束式剪力钉布置方式制作剪力群钉推出试件,并进行推出试验,得知群钉中最不利的单个剪力钉承担了32%~37%的总剪力(平均值仅为25%);由大跨度组合箱梁整体模型计算得到剪力群钉受力均值、钢-混凝土相对位移及钢梁与混凝土桥面板的受力状况;根据剪力群钉荷载分配比例对组合梁整体计算得到的剪力钉计算结果进行修正.结果表明,将剪力群钉受力均值换算得到剪力钉受力极值的方法,可实现对大跨度组合梁及其剪力钉的精确仿真分析.%When the simulation analysis of a composite girder is made,the way of simplifying the multiple shear studs of the girder into the equivalent group shear studs can not exactly acquire the force condition of each stud.To solve the problem,the push-out specimen of the group shear studs was fabricated according to the clustering layout of the shear studs of the practical bridge,the push out test for the specimen was carried out and it was consequently known that the single stud in the group shear studs under the worst force condition sustained 32%~37% of the total shear force (while the average value was 25% only).From the calculation of the integral model of the long span composite box girder,the force average values of the group shear studs,the relative displacement of the steel and concrete and the force conditions of the steel girder and concrete deck slabs were acquired and with reference to the load distribution ratios of the group shear studs,the calculation results of the shear studs were modified.The results of the calculation and modification demonstrate that by way of converting from the force average values of the group shear studs to the force ultimate values of the shear studs,the accurate simulation analysis of

  19. Design Analysis on Steel-Concrete Transition Section of Main Girder of Shangdi Bridge on Beijing-Xinjiang Expressway%京新上地桥主梁钢-混过渡段的设计分析

    Institute of Scientific and Technical Information of China (English)

    徐升桥; 刘永锋

    2013-01-01

    京新上地桥的曲线混凝土主梁采用单点顸推法施工,顶推总重250 000 kN,顶推距离213 m,顶推过程最大悬臂长度63 m.钢导梁预埋于主梁前端,通过剪力连接件和混凝土箱梁连接成整体,以传递顶推过程中的弯矩和剪力.对钢-混凝土过渡段顶、底、腹板的连接件受力性能进行设计分析,并建立实体模型详细分析最不利工况下关键部位的局部应力,结果表明界面连接可靠,钢-混凝土过渡段变形协调、应力分布均匀,设计合理.%Single-point incremental launching method is employed to construct the curved concrete main girder of Shangdi Bridge on Beijing - Xinjiang Expressway. During the incremental launching construction, the total launching weight, distance and maximum cantilever length is respectively 25 000 t, 213 m and 63 m. In order to transfer bending moment and shear force, the steel launching nose is pre-embedded in the front end of the concrete main girder, and is integrally connected with the concrete box girder by shear connectors. For the steel-concrete transition section; mechanical performance of connectors at the top, bottom and web slabs are analyzed firstly; and then, local stress at key positions under the most unfavorable conditions are precisely analyzed by means of solid model. The analysis results show that: connection of the interface is reliable, deformation of the steel-concrete transition section is compatible, and stress distribution is uniform, which indicate that the design is reasonable.

  20. Ansys -based research on fatigue crack of welded box girder for overhead travelling crane%基于Ansys的桥式起重机焊接箱形梁疲劳裂纹研究

    Institute of Scientific and Technical Information of China (English)

    殷玉枫; 曾光; 吕西波; 张孟辉

    2012-01-01

    The box girder of overhead travelling crane features typical thin-wall structure, in which fatigue crack can appear easily due to load situation and weld defects of the crane, etc. Considering such case, the Ansys finite element software is adopted for load analysis of typical working conditions of the box girder in order to figure out the position and causes of any crack, and the fracture mechanics and Ansys software are adopted for analysis and simulation of the stress field, displacement field of the fatigue crack in box girder, as well as the size of stress field, which is significant to estimate the fatigue crack expansion and remaining life of the crane box girder.%桥式起重机箱形梁是典型的薄壁结构,由于起重机受载情况及本身结构焊接缺陷等因素,在箱形梁上很容易出现疲劳裂纹.针对桥式起重机箱形梁疲劳裂纹现象,借助Ansys有限元软件,对箱形梁典型工况进行受载分析,判断出裂纹的位置及其产生原因;运用断裂力学和Ansys软件分析模拟出箱形梁疲劳裂纹的应力场、位移场以及应力场区域的大小,对起重机箱形梁进行疲劳裂纹扩展以及剩余寿命的预估都有意义.

  1. 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)

  2. Automated outlier detection framework for identifying damage states in multi-girder steel bridges using long-term wireless monitoring data

    Science.gov (United States)

    O'Connor, Sean M.; Zhang, Yilan; Lynch, Jerome P.

    2015-04-01

    Advances in wireless sensor technology have enabled low cost and extremely scalable sensing platforms prompting high density sensor installations. High density long-term monitoring generates a wealth of sensor data demanding an efficient means of data storage and data processing for information extraction that is pertinent to the decision making of bridge owners. This paper reports on decision making inferences drawn from automated data processing of long-term highway bridge data. The Telegraph Road Bridge (TRB) demonstration testbed for sensor technology innovation and data processing tool development has been instrumented with a long-term wireless structural monitoring system that has been in operation since September 2011. The monitoring system has been designed to specifically address stated concerns by the Michigan Department of Transportation regarding pin and hanger steel girder bridges. The sensing strategy consists of strain, acceleration and temperature sensors deployed in a manner to track specific damage modalities common to multigirder steel concrete composite bridges using link plate assemblies. To efficiently store and process long-term sensor data, the TRB monitoring system operates around the SenStore database system. SenStore combines sensor data with bridge information (e.g., material properties, geometry, boundary conditions) and exposes an application programming interface to enable automated data extraction by processing tools. Large long-term data sets are modeled for environmental and operational influence by regression methods. Response processes are defined by statistical parameters extracted from long-term data and used to automate decision support in an outlier detection, or statistical process control, framework.

  3. MECHANICAL BEHAVIOR OF STUD SHEAR CONNECTORS IN COMPOSITE GIRDER OF APPROACH BRIDGE OF JIUBAO BRIDGE%九堡大桥引桥组合梁焊钉受力性能研究

    Institute of Scientific and Technical Information of China (English)

    高璞

    2012-01-01

    九堡大桥引桥为多跨连续组合箱梁桥,截面为开口梯形钢梁与混凝土桥面板组合形式,钢梁与混凝土板间设置了大量的圆柱体焊钉连接件,连接件受力形式与传统钢板梁组合桥不同.文中结合该工程,采用ANSYS有限元程序建立其空间实体模型,采用弹簧单元详细模拟了焊钉,计算了焊钉连接件的受力,分析了焊钉连接件的受力特点.结果表明:焊钉连接件不仅承受沿纵桥向的剪力,还承受沿横桥向的剪力及沿竖向的拉拔力,连接件所受的剪力和拉拔力在全桥范围分布规律复杂.%The approch bridge of Jiubao bridge was a multi - span continous composite bridge,whose cross section composed of open trapezoid section steel girder and concrete slabs. Magnitude of headed studs were layout at die interface of steel girder and concrete slab. Mechanical behavior of studs in this type of composite beam is different from that in the steel plate composite beam. Combined with this project, finite element program ANSYS was used to set the solide spatial model in which spring elements were adopted to simulate the studs. Thus mechanical behavior of studs were achieved and analyzed. The analysis results show that; studs carry not only longitudinal shear force along the bridge;but also transverse shear force and vertical tension force, the distribution patterns of diese forces along the whole bridge were complex.

  4. Stationary seismic analysis of multi-span simply supported girder bridge%多跨简支梁桥平稳地震响应分析

    Institute of Scientific and Technical Information of China (English)

    马青青; 张鸿儒

    2013-01-01

    应用单位脉冲函数,建立了简支梁桥的纵向振动频响函数方程,基于传递函数,提出了用于求解多跨简支梁桥纵向位移和轴力的动态频响函数的计算方法.以六跨简支梁桥为算例,求解了跨中最大位移和轴力,并给出了脉冲荷载作用下相应的傅里叶振幅谱.结果表明,中间各跨跨中位移较大,两侧跨中轴力较大,响应谱的变化规律与位移和轴力的变化一致.%Based on the unit impulse function principle, the frequency response function equation of longitudinal vibration for simply supported beam bridge is established. According to the transfer matrix principle, the calculation method of the dynamic frequency response function for the vertical displacement and axial force of multi-span simply supported beam bridge is proposed. Taking six cross-simply supported girder bridge as an example, the maximum displacement and axial force are solved, and the corresponding Fourier amplitude spectrum under pulse loads is provided. The calculation results show that the mid-pan displacement in the middle of the bridge is bigger than that in the side of the bridge, but the axial force shows an inverse tendency. The changes of the amplitude spectrums are consistent with the displacement and axial force respectively.

  5. Design of (70+125+70) m Continuous Girder Bridge by Swing Method Crossing above Existing Railways%(70+125+70)m跨铁路转体连续梁桥设计

    Institute of Scientific and Technical Information of China (English)

    刘润舟

    2013-01-01

    Crossing above both the Nanchang-Jiujiang Intercity Railway and Beijing-Kowloon Railway, the main bridge of Gong’an Bridge is a continuous prestressed concrete girder bridge with the span arrangement of (70+125+70)meters. This thesis introduced how to select the bridge site and bridge type, how to design the bridge structure, how to select the calculation parameters, and how to erect the girder by swing method. Meanwhile, by using finite element software named Dr. Bridge, the bridge structure was calculated and analyzed longitudinally and transversely, and the results show that all the structural strengths, stresses, displacements, etc. can accord with the relevant provisions of the design codes.%共安大桥主桥上跨昌九城际、京九铁路,采用(70+125+70) m预应力混凝土连续梁,对桥位和桥型确定、桥梁结构设计和计算参数选取,以及转体施工方案进行介绍。采用有限元软件桥梁博士对桥梁结构进行纵向计算分析,结果表明结构强度、应力、位移等均满足设计规范的有关规定。

  6. CALCULATION AND ANALYSIS ON FLEXURAL CAPACITY OF PRESTRESSED COMPOSITE BOX GIRDER%预应力组合箱梁抗弯能力计算分析

    Institute of Scientific and Technical Information of China (English)

    胡少伟; 胡汉林

    2012-01-01

    The prestressed steel and concrete composite beams having been widely used in engineering as a new transverse bearing component.The bending capacity is one of the most fundamental and important behaviors.The calculation formulas of elastic bearing capacity and deflection were derived considering the slip at the steel-concrete interface and the stress increments of prestressed tendons on the base of the elastic theory;and on the premise of plane section and complete composite action,the expressions of prestressed composite beam's ultimate plastic capability which consider the stress increments of prestressed tendons were deduced,based on the simplified plastic theory.These foumulas can reflect the characteristics of the prestressed composite box girder.It turns out that the calculation values are in good agreement with the experimental results,which meet the engineering accuracy.%预应力钢-混凝土组合梁作为一种新型的横向承重构件,在工程中得到了广泛的使用,准确计算其抗弯承载能力是工程上最为基本也是最重要的要求。该文以弹性分析理论为基础,推导了考虑交界面相对滑移和预应力增量的预应力组合梁弹性承载能力和挠度计算公式;以完全协同作用和平截面假定为前提,采用简化的塑性理论,推导了考虑预应力增量的极限抗弯承载能力计算公式。公式能够反映预应力组合梁的受力特点,计算结果与试验值吻合良好,满足工程精度。

  7. M PC复合材料加固空心板梁桥静载试验研究%Study of Static Tests for Using MPC Composite Material to Strengthen Void Plate Girder Bridge

    Institute of Scientific and Technical Information of China (English)

    谷丹丹; 孙全胜

    2015-01-01

    为研究M PC复合材料加固空心板梁桥的有效性,在某跨径13 m的空心板梁桥主梁跨中11 m范围内浇筑M PC复合材料进行加固,桥梁加固前与加固后分别进行静载试验,并采用有限元法建立加固前后主梁的有限元模型,分析加固前后主梁的挠度、裂缝和应变的变化。分析结果表明:工况1(跨中最大弯矩横向对称加载)、工况2(跨中最大弯矩横向偏载加载)下主梁加固后的挠度较加固前分别降低了13.4%、12.6%,加固后主梁的挠度明显减小;在试验过程中,加固后主梁裂缝未见明显变化,裂缝区应变水平降低,较好地抑制了原有裂缝的发展;工况1、工况2下主梁加固后的应变较加固前分别降低了13.75%、14.79%,加固后主梁受拉区应变显著降低;加固后校验系数改善率最大为13.89%,该加固方法能够有效地提高桥梁的承载力和刚度。%To study the efficiency of using MPC composite material to strengthen void plate girder bridge ,within the 11 m area of the midspan of the main girder of a 3 × 13 m void plate girder bridge ,the MPC composite material was cast for the strengthening purpose .Static tests were done before and after the strengthening ,and the finite element method was used to establish the models of the main girder before and after the strengthening ,to analyze the variation of main span deflec‐tion ,cracking and strain .The results of the analysis indicate that under two load cases (load case 1 is the transverse symmetrical loading with maximum midspan bending moment and the load case 2 is the transverse eccentric loading with maximum midspan bending moment .) ,the deflection of main girder reduces by 13 .4% and 12 .6% , respectively , compared with the data before the strengthening ,and the deflection of the main girder after strengthening is distinctively declined . During the process of the tests ,the cracking of the main

  8. Load transverse distribution of single box multi-cell girder with corrugated steel webs%单箱多室波形钢腹板箱梁荷载横向分布

    Institute of Scientific and Technical Information of China (English)

    马磊; 万水; 蒋正文; 李明鸿

    2014-01-01

    A formula for calculating the load transverse distribution coefficient of single box multi-cell girder with corrugated steel webs was deduced by the rigid connected beam method on the basis of the equivalent plane plate-girder model.Then,a test on a single box double-cell girder with cor-rugated steel webs was carried out to research its load transverse distribution.The research results show that the error between the load transverse distribution coefficient calculating with rigid connect-ed beam method and that obtained from test and finite element analysis is less than 7%.Compared with the finite element analysis result of the girder with midspan diaphragm,the load transverse dis-tribution coefficient calculated by the rigid connected beam method is relatively safe.Thus the rigid connected beam method can be used to calculate the load transverse distribution coefficient of the sin-gle box double-cell girder with corrugated steel webs where or not there is a diaphragm in the mids-pan of the girder.The distribution law of the load transverse distribution coefficient along the longi-tudinal of single box multi-cell girder with corrugated steel webs was suggested according to the ex-perimental results.The moment transverse distribution coefficients are mc ,where mc is the load trans-verse distribution coefficient at the middle span calculated by the rigid beam method.For the support reaction transverse distribution coefficients of the middle girder,0.6m0 is used at the end,where m0 is the load transverse distribution coefficient at the end calculated by the level principle method;mc is applicable from L/4 to L;and the transition from the end to L/4 is linear.The support reaction transverse distribution coefficients of the side girder are 0.9m0.%将单箱多室波形钢腹板箱梁等效为平面板梁模型,用刚接梁法推导了单箱多室波形钢腹板箱梁荷载横向分布系数的计算公式,并对1根单箱双室波形钢腹板箱梁进行了荷

  9. 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.

  10. Vortex-induced resonance characteristics and anti-vibration measures'mechanism of central-slotted box girders%中央开槽箱梁涡激共振特性及抑振措施机理研究

    Institute of Scientific and Technical Information of China (English)

    杨婷; 周志勇

    2015-01-01

    To study vortex-induced resonance characteristics and anti-vibration measures'mechanism of central-slotted box girders,the large-scale sectional model vibration measurement,pressure measurement and CFD were employed.A long-span cable-stayed bridge over Yangtze River was taken as an example to conduct wind tunnel tests of large-scale sectional model.The test results indicated that it is the maintenance rails located inside aerodynamic susceptible sites that cause the vortex-induced vibration of the bridge.CFD numerical simulation results showed that the upwind flow passing through the curved soffit plate is hindered by the inside maintenance rails to cause an increased width of dead water region in the wake of upwind box section,a continuous and intensive vortex shedding phenomenon occurs due to velocity gradient and the VIV of the bridge main beam section takes place;accordingly,the inside maintenance rails are proposed to offset the center line of the main beam with a certain distance,they are not an obstacle to the high-speed upwind flow;thus the flow separates at the location far away from the knuckle line and the size of dead water region in the upwind box wake is reduced to prevent the vortex shedding.The static pressure test results showed that when shifting the inside maintenance rails,the negative mean pressure at the soffit plate knuckle line,does not change dramatically,the fluctuating pressures on the upwind and downwind inclined panels can be reduced,and the fluctuating energy is dispersed without a consistent predominant frequency.Wind tunnel tests for the modified section were conducted and the results showed that the VIV of the bridge can be suppressed completely.%基于大比例节段模型风洞测振、测压试验及计算流体力学(Computational Fluid Dynamic,CFD)方法进行中央开槽箱梁涡激共振特性及抑振措施机理研究。以芜湖长江公路二桥为例进行大比例节段模型风洞试验。结果显示,位于

  11. Validation of connection details between a UHPFRC ribbed slab and steel girders for a new composite bridge deck type

    OpenAIRE

    Toutlemonde, François; LAUVIN, Ludovic; Renaud, Jean Claude; BABY, Florent; Bouteille, Sébastien; RESPLENDINO, Jacques

    2008-01-01

    Within the French R & D project MIKTI focusing on innovative steel-concrete composite bridges, an exhaustive experimental program was carried out to provide an experimental validation of a new ultra-high performance fibre reinforced concrete (UHPFRC) 2 way-ribbed slab made of segments assembled by post-tensioning. Provisions concerning the realization of connection between the UHPFRC ribbed deck and steel profiles, which are critical for ensuring the composite behavior of the full structure, ...

  12. Effect of Plate Girder Bridge with Different Coupling Stiffness on Stress of Concrete Slab%不同连接程度板桁桥对混凝土板应力的影响

    Institute of Scientific and Technical Information of China (English)

    任钢; 肖杰; 丁颖

    2012-01-01

    In terms of 64m through semi-combined plate girder bridge which is used more widely at present,the effect of coupling stiffness between concrete steel truss girder and distribution distance of shear key on concrete slab is analyzed and compared by changing the coupling stiffness and distribution distance.The calculation shows that with the increase of coupling stiffness axial stress of concrete slab increases while beading stress is slightly affected.By decreasing the distribution distance of shear key,stress of concrete slab at the upside of longitudinal girder is largely affected and the stress at the edge while along the center line is slightly affected.%针对目前高速铁路应用较多的64m下承式板桁半结合桥,通过改变混凝土与钢桁梁之间连接刚度以及剪力键分布距离来分析比较其对混凝土应力的影响,计算表明,连接刚度的增加,混凝土板的轴向应力随之增加,但弯曲应力影响较小。通过剪力键布置间距减小,纵梁上方处混凝土板应力影响较大,而混凝土边缘以及中心线处应力影响较小。

  13. 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

  14. 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.

  15. Experimental Study on Vehicle-Bridge Dynamic Characteristics of Thin-Walled Trough Girder Bridge for Urban Rail Transit%城市轨道交通薄壁槽形梁车桥动力特性试验研究

    Institute of Scientific and Technical Information of China (English)

    吴亮秦; 吴定俊; 李奇

    2011-01-01

    Field tests were conducted on a standard span thin-walled trough girder bridge for the elevated urban rail transit. The free vibration characteristics of the bridge, such as the frequency, mode and damping ratio were got. The test data for both the bridge and train during the train passing through the bridge, including the displacement, amplitude, stress and the acceleration responses of the bridge and the acceleration of the carbody were obtained and analyzed. The analysis results show that the deflection-span ratio of the girder body is less than the code limit. No resonance phenomenon occurs as the train passing through the bridge. The vertical stiffness of the girder body meets the requirements. The transverse fundamental frequency of the girder span is greater than the code value while the transverse fundamental frequency of the bridge is smaller. The lateral amplitude at the pier top is larger. The transverse stiffness of the girder body meets the requirements, whereas the stiffness of the pier is somewhat insufficient. Local vibration is found in the roadbed slab and the web. Therefore, more attention should be paid to the local stability of running lines and the web when the design speed is increased. The total longitudinal bending dynamic coefficient of the girder body is smaller than specification regulated value. However, the local transverse bending dynamic coefficient of the roadbed slab is much larger than the total longitudinal bending dynamic coefficient of the girder body. The acceleration of the bridge deck is within the limit. Judging by Sperling index and ISO2631 evaluation index, the ride comfort of the test train running on the bridge is found to be excellent. According to the test and analysis, thin-walled trough girder is proved to be suitable for elevated urban rail transit.%对城轨高架标准跨薄壁槽形梁桥进行现场测试,获得桥梁的频率、振型、阻尼比等自振特性,以及列车通过时桥梁的位移、振幅

  16. Calculation of Flexural Capacity for Prestressed Box Girder with Corrugated Steel Webs Considering Shear Slip%考虑剪切滑移的波纹钢腹板预应力箱梁抗弯承载力计算

    Institute of Scientific and Technical Information of China (English)

    任红伟; 刘保东; 李鹏飞

    2012-01-01

    In order to calculate the ultimate flexural capacity for externally prestressed box girder with corrugated steel webs, in view of its structural characteristics, considered the shear slip of shear key between the corrugated steel webs and the roof and floor concrete, the formulas of the ultimate flexural capacity of the externally prestressed box girder with corrugated steel webs were derived. As the slip strains increased the strain of the roof and floor and the sectional curvature, the influence of the interfacial slip on the ultimate flexural capacity were taken into account by the additional moment. Based on the analysis of the compatibility relation between externally prestressed tendons and the beam deformation, the stress increment of the external prestressing tendons was derived, the calculating steps of the ultimate flexural capacity of the externally prestressed box girder with corrugated steel webs by the plastic hinge method were derived and summarized, and the method was verified by model tests. The comparison of the experimental and theoretical results indicate that (1) the ultimate flexural capacity will be reduced when considering shear slip of the shear key; (2) the results obtained using the derived formulas are better than those from existing methods, which are close to the measured values and can give a reference to the calculation of the same type of girders.%为了计算体外预应力波纹钢腹板组合箱梁桥的极限抗弯承载力,针对其构造特点,考虑波纹钢腹板与顶底板混凝土剪力连接键剪切滑移的影响,推导了波纹钢腹板预应力箱梁极限抗弯承载力计算公式.滑移应变增大了项底板的应变和截面曲率,可以通过附加弯矩考虑界面滑移对极限抗弯承载力的影响;在分析体外预应力钢筋与梁体变形协调关系的基础上,得到了体外预应力筋的应力增量,推导并总结了应用塑性铰法计算波纹钢腹板体外预应力组合箱梁极限抗

  17. 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

  18. Acoustic emission monitoring for assessment of steel bridge details

    International Nuclear Information System (INIS)

    Acoustic emission (AE) testing was deployed on details of two large steel Interstate Highway bridges: one cantilever through-truss and one trapezoidal box girder bridge. Quantitative measurements of activity levels at known and suspected crack locations were made by monitoring AE under normal service loads (e.g., live traffic and wind). AE indications were used to direct application of radiography, resulting in identification of a previously unknown flaw, and to inform selection of a retrofit detail.

  19. Analysis of Influence Factors of Structure Stability for SingleColumn Pier Continuous Girder Bridge%独柱墩连续梁桥的稳定影响因素分析

    Institute of Scientific and Technical Information of China (English)

    吴玉华; 蔡若红; 杨育人

    2011-01-01

    Taking the case of Jinhua-Taizhou section of zhuyong highway, 23 simulation models of single-column pier continuous girder bridge were established by MIDAS finite element program. The major factors which would affect the stability of curved girder bridge, such as the radius of curvature, the length of bridge, the space between two bearings and the offset distance of bearing placed on the single-column pier etc. The results show that the radius of curvature has great effect on the negative counter-force of bearing. The bearing separation is likely to occur when the radius of curvature is less than 200 m and the length of bridge is greater than 100 m. That the appropriate layout offset distance of bearing and enlargement of the space between bearings can assure lower possibility of bearing separation and enhance the ability of bridge performance against overturning.%以诸永高速金华台州段工程为例,采用MIDAS有限元分析程序,构建了23座独柱墩连续箱梁桥的仿真模型,系统分析和总结了影响弯梁桥稳定性的主要影响因素,如曲率半径、桥梁长度、联端支座间距、独柱墩支座预设偏心等.结果表明:桥梁曲率半径对支座负反力影响很大,当曲率半径小于200 m,桥梁长度大于100 m时较易发生支座脱空现象;增大联端支座间距,合理设置支座偏心距,可减小支座出现脱空的可能性,提高桥梁的抗倾覆能力.

  20. 黄冈公铁两用长江大桥钢桁梁杆件制造关键技术%Key Techniques for Manufacturing of Members of Steel Truss Girder of Huanggang Changjiang River Rail-cum-Road Bridge

    Institute of Scientific and Technical Information of China (English)

    殷红

    2013-01-01

    The main bridge of Huanggang Changjiang River Rail-cum-Road Bridge is a steel truss girder cable-stayed bridge with double pylons and double cable planes.The chord and web members of the main truss of the bridge were designed as the ones of parallelogram sections.To guarantee the manufacturing quality of the members,the key techniques for the manufacturing were studied.The precision of the geometric dimensions of the members was guaranteed by the techniques of controlling the precision of the inclined angle grooves of the welded edges,fine adjusting the diagonal line dimensions of the diaphragms (controlling the angles of the end openings) and assembling the members on the special jig supports.The precision of the anchor tube positioning was guaranteed by the techniques of converting the spatial positioning dimensions of the anchor tubes into the plane positioning dimensions and controlling the installing,welding procedures of the anchor boxes and the installing precision of the anchor tubes.The assembling quality of the steel truss girder was guaranteed by the techniques of testing the precision of the hole groups at the inclined web member joints by the special testing templates for the web member joints.Practice proves that the key techniques applied to the manufacturing of the members effectively tackle the control problems of the members of parallelogram sections and guarantee the manufacturing precision of the steel truss girder of the bridge.%黄冈公铁两用长江大桥主桥为双塔双索面钢桁梁斜拉桥,其主桁弦杆和腹杆采用平行四边形截面.为保证主桁平行四边形截面杆件的制造质量,对其制造关键技术进行研究.通过控制杆件焊接边斜角坡口精度、微调隔板对角线尺寸(控制端口角度)、应用专用胎架组拼杆件的技术保证杆件形位尺寸的精度.通过将锚管空间定位尺寸转化为平面定位尺寸、控制锚箱安装及焊接工序、控制锚管安装精度的技术

  1. 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.

  2. 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.

  3. 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...

  4. Box girder vertical displacement monitoring for Xujiawan continuous rigid aqueduct water filling test%徐家湾连续刚构渡槽充水试验箱梁竖向位移监测

    Institute of Scientific and Technical Information of China (English)

    张健; 钟伟

    2016-01-01

    为了检验徐家湾连续刚构渡槽箱梁的安全性能,经过近42天5级加载充水试验,监测结果表明:徐家湾渡槽箱梁竖向位移与设计理论值一致,渡槽施工质量良好,结构安全。其成果可供类似连续刚构渡槽充水试验参考。%In order to check the safety of box girder of Xujiawan continuous rigid aqueduct,5-grade loading water filling test was conducted for nearly 45 days. The results of monitoring demonstrate the vertical displacement is identical with the design value,the construction quality is good,and the structure is safe. The results also can be reference for water filling test of similar rigid aqueduct.

  5. 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

  6. Replacement of roller-track girder on overburden conveying bridge F60 at the Walzow opencast mine of LAUBAG; Rollbahntraegerwechsel an der Abraumfoerderbruecke F60 im Tagebau Welzow der Lausitzer Braunkohle AG

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, E. [LAUBAG, Senftenberg (Germany); Nies, G. [MAN TAKRAF Foerdertechnik GmbH, Lauchhammer (Germany)

    1996-11-01

    After an operating time of about 20 years damage, mainly in the form of cracks in welds, occurs on the roller-track girders of the overburden conveying bridges. The causes of this damage are the quality of the H 45/60 steel that is used and the structural design of this assembly. In order to ensure safe operation of the conveying bridge until such time as the Welzow-South opencast mine is worked-out, the main over-run sections were replaced. Including all secondary and auxiliary structures, about 700 t of steel structure had to be fabricated anew. This entire replacement campaign was accompanied by a number of quality assurance measures in order to preclude any subsequent reworking, which would entail great expense. (orig.) [Deutsch] Nach ca. 20jaehriger Betriebszeit kommt es an den Rollbahntraegern der Abraumfoerderbruecken zu Schaeden, hauptsaechlich zu Schweissnahtrissen. Ursachen dafuer sind die Qualitaet des eingesetzten Stahles H 45/60 und die konstruktive Gestaltung dieser Baugruppe. Um die Foerderbruecke bis zum Auslaufen des Tagebaues Welzow-Sued sicher betreiben zu koennen, wurden die Hauptueberrollbereiche ausgetauscht. Einschliesslich aller Neben- und Hilfskonstruktionen mussten ca. 700 t Stahlbau neu gefertigt werden. Die gesamte Massnahme wurde begleitet von einer Reihe Qualitaetssicherungsmassnahmen, um jegliche Nacharbeit, die sehr aufwendig waere, auszuschliessen. (orig.)

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

    OpenAIRE

    2014-01-01

    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 trai...

  8. 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 are...

  9. 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.

  10. Parameterized Design for Bridge Crane Girder base on Time-variant Reliability%基于时变可靠性的桥式起重机主梁参数化设计

    Institute of Scientific and Technical Information of China (English)

    杨瑞刚; 朱希涛

    2014-01-01

    为提高我国起重机产品的安全可靠性水平,根据桥式起重机的工作特点,针对静态可靠性方法在评估结构可靠度时没有考虑金属结构抗力和载荷效应随时间变化的情况,采用时变可靠性分析理论,结合 Visual C++6.0开发环境中的 MFC,集成 ANSYS 二次开发语言 APDL,研发了桥式起重机主梁参数化建模设计软件,为桥式起重机主梁结构时变可靠性分析提供了一种可行的方法。经验证,时变模型能更好地反映结构的实际可靠度,同时也证明了时变模型的合理性。%In order to improve the safety performance of the cranes and large machinery products,according to work characteristics of the overhead traveling crane ,Static reliability in the assessment of structure without considering the struc-tural resistance and load effects change over time,time reliability theory has been used,by using development environment MFC of Visual C++6.0,integrated the secondary development language APDL in the ANSYS software,so the overhead traveling crane bridge structure interaction parameter modeling and finite element analysis of visualization software is devel-oped,Meanwhile a feasible method of reliability analysis for the Bridge crane girder is also provided.After verify time-var-ying model can better reflect the actual reliability of the structure,and verify the time-varying model is reasonable.

  11. 箱形梁剪力滞效应分析中的翘曲位移函数及广义内力研究%Study on warping displacement function and generalized internal force in shear lag effect analysis of box girder

    Institute of Scientific and Technical Information of China (English)

    张元海; 康喜东; 林丽霞

    2012-01-01

    Based on the flexural theory of thin-walled box girder, the curve of quadratic parabola is proved to be the reasonable form of the warping displacement function in the shear lag effect analysis of a box girder through investigating the in-plane shear deformation and the bending shear flow distribution in the flanges. The additional deflection induced by shear lag effect is adopted as the generalized displacement. The governing differential equations and the corresponding boundary conditions for shear lag effect of box girder are established by the energy calculus of variations based on the principle of minimum poten- tial energy. The new generalized internal force is defined rigorously,and a simple and convenient formula of stress for shear lag warping is presented which has the same form as the bending stress of elementary beam. A simply supported box girder model is analyzed and the calculated results are in good agreement with the test results, validating the method and formula presented. The generalized moment for shear lag differs from the bending moment in distribution and attenuates quickly. For the simply supported box girder example under concentrated load, shear lag effect increases the mid-span deflection by 12 ~,which should be treated carefully in practice.%以薄壁箱梁的弯曲计算理论为基础,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。选取剪力滞效应引起的附加挠度作为广义位移,用基于最小势能原理的能量变分法建立箱形梁剪力滞效应分析的控制微分方程和边界条件。对箱粱横截面上新出现的广义内力给出严密定义,并建立了剪力滞翘曲应力的简便计算公式,它与初等梁弯曲应力公式具有相同的形式。对一个简支箱梁模型的计算表明,计算值与实测值吻合良好,从而证实了本文的分析方

  12. 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.

  13. 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.

  14. Innovative configurations for long-span suspension bridges

    OpenAIRE

    Bartoli, G.; P. D’Asdia; S. Febo; C. Mannini; S. Noè; L. Procino

    2009-01-01

    This paper reports the results of a piece of research about long-span suspension bridges with multiple-box girder steel deck characterized by low drag coefficient and high aeroelastic stability. For this type of bridges, by increasing the span length, the contribution to the stiffness of the suspension cables becomes dominant with respect to that of the deck, so that the ratio of the frequency of the first torsional mode to the frequency of the first vertical bending mode approaches unity, wh...

  15. Computational fluid dynamic analysis of flutter characteristics for self-anchored suspension bridges

    Institute of Scientific and Technical Information of China (English)

    Zhiwen ZHU; Zhaoxiang WANG; Zhengqing CHEN

    2008-01-01

    This paper outlines the essentials and proce-dures of computational fluid dynamics (CFD) simulation applicable to evaluating flutter derivatives of bridge decks. An arbitrary Lagrangian-Eulerian (ALE) description of the flow around the moving rigid box girder combined with the finite volume discretization and multi-grid algorithm is pre-sented. The proposed methods are employed to identify flutter derivatives of the bridge deck of the Sanchaji Self-anchored Suspension Bridge. The results agree well with ones from wind tunnel tests. It demonstrates accuracy and efficiency of the present method.

  16. Application of Lead Core Rubber Bearings to Seismic Mitigation and Isolation of Simply-Supported Girder Bridges%铅芯橡胶支座在简支梁桥减隔震中的应用

    Institute of Scientific and Technical Information of China (English)

    宋雷; 贺立新

    2012-01-01

    To study the effect of seismic mitigation and isolation of the lead core rubber bearings applied to the simply-supported girder bridges in high intensity seismic region, the Shuijing Bridge was cited as an example and was analyzed. The ANSYS was used to respectively set up the finite element models for the whole bridge of the bridge in both the seismic isolation state and non-seismic isolation state and in consideration of the ground base pile~soil interaction of the bridge, the response spectrum analysis was made, using the calculated response spectra of 10% and 2% of the 50-year exceeding probability and the time-history analysis was made as well, u-sing the seismic waves of the exceeding probability that are identical to the response spectra. The results of the analysis indicate that in the non-seismic isolation state, the displacement and internal forces of the piers of the bridge under the action of Earthquake El and E2 are great. The common plate rubber bearings can not cater for the need of strength and deformation of the piers while with the applying of the lead core rubber bearings, the displacement and internal forces of the piers are effectively reduced and sound effect of the seismic isolation has been achieved. In the analysis of the seismically-mitigated and isolated bridge, using the response spectrum analysis method and by way of considering the equivalent rigidity of the seismic isolation components in the analysis, the nonlinear issue can be simplified as the linear-elastic issue for handling.%为研究在高地震烈度区将铅芯橡胶支座应用于简支梁桥的减隔震效果,以水晶大桥为例进行分析.采用ANSYS分别建立隔震状态和非隔震状态的全桥有限元模型,考虑地基桩一土作用效应,取用50年超越概率10%和2%的计算反应谱进行反应谱分析,并取用与反应谱相同超越概率的地震波进行时程分析.分析结果表明:非隔震状态时,该桥在E1和E2地震作用下桥墩的

  17. Installation and Control of Large Post-tensioning Pre-stressed High-performance Concrete Box Girders for an Ore Terminal%大型后张预应力高性能混凝土箱梁在矿石码头中的应用控制

    Institute of Scientific and Technical Information of China (English)

    马玉臣

    2011-01-01

    The use of large post-tensioning pre-stressed high-performance concrete box girders used in deepwater berths especially for ore terminals to accommodate ships of more than 250 000 tons is still unprecedented in China. The paper describes that the prestressed girders are suitable for the load and process requirements through various quality control procedures during the construction of Caofeidian Ore Terminal and the successful engineering practice ran provide references for similar projects.%大型后张预应力高性能混凝土箱梁应用在深水泊位特别是25万吨级以上的矿石码头国内尚无先例,文中阐述了该预应力梁在曹妃甸矿石码头工程施工过程中通过多方面质量控制,较好地适应了荷载和工艺要求,其成功应用可为以后类似工程提供借鉴.

  18. 某曲线梁桥双支座反力调整%A Curved Girder Bridge Double Bearing Anti-force Adjustment

    Institute of Scientific and Technical Information of China (English)

    刘庚

    2012-01-01

    Taking interchange rubber plate with a reaction force adjustment as an example, the paper is to introduce continuous beam bridge to use steel structure as scaffold platform when rubber bearings hanging in the air or bearing shifted, changes of deck cross slope, beam body occurring displacement, and on the platform, set slid, top up (shift) beam jack, using ordered rising of jack to conduct righting, pan, adjustable slope elevation, consolidation, replacement of bearings and fallen beam in place for beam body, so that on the beam is situated in the design position step by step, in order to restore normal use of bridge.%以某立交板式橡胶支座反力调整为例,介绍连续梁桥在橡胶支座脱空或支座发生位移、桥面横坡发生变化、梁体发生各项位移时,采用钢结构作为支架构建操作平台,平台上设置滑道,顶升(移)梁体千斤顶,利用千斤顶的有序起项,对梁体进行起顶扶正、平移、调坡抬高,加固、更换支座和落梁就位,使梁体一步一步地就位于设计位置,以恢复桥梁正常使用.

  19. 佛陈大桥(扩建)连续钢箱梁设计%Design of Continuous Steel-box Girder in Fochen Extension Bridge

    Institute of Scientific and Technical Information of China (English)

    郑楷柱; 何海; 梁立农; 饶瑞

    2015-01-01

    变截面连续钢箱梁在国内应用方兴未艾,对其研究和成熟工程案例相对较少.本文从佛陈大桥(扩建)连续钢箱梁的结构、防腐、铺装、架设等方面进行深入研究并精心设计,使其很好地结合了桥位所处的环境,满足了施工工期的要求.

  20. Optimal Design for UHPC Continuous Box Girder Bridge with 400 m Main Span%主跨400 m的UHPC连续梁桥优化设计

    Institute of Scientific and Technical Information of China (English)

    刘勇; 邵旭东; 詹豪

    2014-01-01

    利用超高性能混凝土(UHPC)的优越性能,提出了与之相适应的新型箱梁结构,目的是利用材料的高强度及新结构的轻型化,解决常规混凝土连续箱梁桥易开裂、下挠和自重过大、跨径难以突破300 m的难题.在原有工作的基础上,对主跨400m的UHPC连续箱梁桥进行了整体性能分析及优化设计,优化内容包括桥梁边跨长度、梁高、板厚等主要参数,以得到其合适的取值范围,根据优化结果建议:边跨与主跨跨径比范围为0.55 ~0.65;中支点梁高与主跨跨径比范围为1/20 ~ 1/25;跨中梁高与支点梁高比范围为1/1.8~1/2.3.整体性能分析结果表明:运用UHPC及新结构,能轻松实现连续梁桥400 m跨径的突破,并具有较大的整体刚度及安全储备.综合考虑长期社会经济效益,在主跨跨径300 ~ 500 m范围内,该新型结构可与斜拉桥、悬索桥等其他桥型形成强有力的竞争选型方案.

  1. 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.

  2. 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.

  3. 大连长山大桥主桥合拢段施工方案%Construction Program of the Main Bridge Closure Section of Dalian Changshan Bridge

    Institute of Scientific and Technical Information of China (English)

    潘宇

    2015-01-01

    The main bridge of Changshan Bridge is twin towers and double cable planes three-span prestressed concrete extradosed cable-stayed bridge, whose main span is 260m, so it has the largest span in the same type of bridge. The main beam uses the prestressed concrete single box three rooms streamlined flat box girder. This paper briefly introduces the construction of main beam closure section.%长山大桥工程主桥为双塔双索面三跨预应力混凝土矮塔斜拉桥,主跨260m,为国内同类型桥梁最大跨径。主梁采用预应力混凝土单箱三室流线型扁平箱梁。文章就主梁合拢段施工作简要介绍。

  4. Application of Hydraulic-Walking Incremental Launching to Steel Arch Girder Construction of Shen′an Huanghe River Bridge in Lanzhou%兰州深安黄河大桥钢拱梁步履式顶推施工技术

    Institute of Scientific and Technical Information of China (English)

    顾乾岗

    2014-01-01

    The main bridge of Shen′an Huanghe River Bridge in Lanzhou is designed as a bow -string steel arch composite girder bridge with a main span of 156 m .The two arch ribs splay out-ward like a butterfly .The main girder is the steel-concrete composite girder with constant cross section .The main bridges characterized by its heavy weight and long spans ,weighs about 4 000 t after all the components are installed .The main bridge construction is likely to impose impact on the navigation channel and the transportation .Due to these reasons ,the steel arch girder is de-signed to be constructed by the hydraulic-walking incremental launching scheme and by way of multiple-point simultaneous incre mental launching .The specialist hydraulic-walking incremental launching equipment was used to carry out the overall incremental launching construction of the main bridge .During the incremental launching construction ,the truss support structure made of steel tubes was added so as to ensure that the load bearing capacity of the bridge in the incremental launching process could meet the requirements .During the construction ,the technique of incre-mental launching along varying vertical curve was adopted ,the elevation of the temporary piers was optimized and determined by optimizing the preliminary elevation and improving the equip -ment .The construction technique was made better by placing the launching nose on the piers and enhancing applicability of the positioning equipment ,achieving the goal of reducing cost and im-proving safety . The engineering experience proves that the incremental launching technique en-sured the safety of the construction process and the geometrical shape of the completed bridge meets the requirements .%兰州深安黄河大桥主桥为主跨156 m 的下承式蝶形钢拱组合梁桥,主梁为等截面钢-混凝土结合梁,主桥全部拼装完总重约4000 t 。针对主桥重量大、跨度大的特点,以及施工对航道、交通的影

  5. 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.

  6. SEISMIC BEHAVIOR OF STEEL MONORAIL BRIDGES UNDER TRAIN LOAD DURING STRONG EARTHQUAKES

    OpenAIRE

    C.W. KIM; Kawatani, M.; Kanbara, T; NISHIMURA, N.

    2013-01-01

    This paper investigated dynamic responses of steel monorail bridges incorporating train-bridge interaction under strong earthquakes. Two types of steel monorail bridges were considered in the study: a conventional type with steel track-girder; an advanced type with composite track-girder and simplified lateral bracing system. During strong earthquakes, monorail train was assumed standing on the track-girder of monorail bridges. Observations through the analytical study showed that considering...

  7. Predicting deflections of a simply supported pre-stressed concrete girder subjected to static loads from observed strains

    Science.gov (United States)

    Mufti, Aftab; Jaeger, Leslie; Klowak, Chad; Kyriakopoulos, Nikolas; Bakht, Baidar; Tadros, Gamil

    2007-04-01

    Deflections of structures, such as bridge girders, are often the most difficult to monitor. Strain measurement is relatively simple with the use of electronic strain gauges, fiber optic sensors, or other strain measuring devices. This paper investigates two different methods for predicting or monitoring the deflection of a simply-supported full-scale bridge girder subjected to a partially distributed uniform load using strain measurements. A full-scale pre-stressed concrete bridge girder was instrumented and tested under a static monotonic load in the linear elastic range. This paper highlights the experimentally measured deflections along the length of one half of the girder and compares them to theoretically predicted deflections and deflections predicted using numerical integration along with harmonic analysis of curvatures determined from theoretical and observed experimental strains. Experimental test results indicate that estimating deflections from observed strains is feasible within the linear-elastic range of such girders. The methods outlined for predicting deflections of full-scale pre-stressed concrete bridge girders from observed strains are a valuable tool for structural engineers and for the periodic and continuous monitoring of civil structures such as bridges.

  8. 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.

  9. 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.

  10. 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%.

  11. Numerical simulation of wind effects on the temperature analysis of bridges

    Science.gov (United States)

    Chen, Lan; Li, Fengwu; Zhou, Linren; Ji, Jing

    2016-04-01

    Structural temperatures and their uneven distributions have significantly negative effects on bridges. It is very important to accurately calculate the structural temperatures. Structural temperatures are deeply affected by the surrounding weather conditions, and the environmental wind is a critical factor. In this study, the wind effects on the thermal analysis of bridges are investigated using numerical simulation. Frist, the traditional theory and method are briefly introduced to show the important effects of wind on structural heat transfer analysis. Then, a new approach is proposed to take account of the wind effects for temperature analysis of bridges. At last, numerical study based on the finite element transient heat transfer analysis of a box-girder bridge is carried out and discussed to verify the proposed method. The results indicate that the proposed method is more reasonable than the traditional methods. This method can be easily implemented in practice for temperature analysis of bridges.

  12. 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.

  13. Damage identification of girder bridge based on nodal curvatures and wavelet analysis%基于节点曲率和小波分析的梁式桥多尺度损伤识别

    Institute of Scientific and Technical Information of China (English)

    钟儒勉; 宗周红; 郑沛娟; 杨泽刚

    2015-01-01

    A damage identification method based on nodal curvatures and wavelet analysis (NCWA)was presented with respect to the Xinyihe Bridge.The proposed methodology was based on the moment -curvature relations and the assumption that internal stress resultants keep invariant before and after damage.Making use of the particular advantage of noise eliminating of wavelet analysis,the linear matrix equations of the pre-damage and post-damage nodal curvatures were solved by using singular value decomposition (SVD).The damage index based on nodal curvature was obtained.A simply supported beam model testing was carried out to verify the feasibility of the proposed method.The sensitivity and anti-noise ability of the damage idenfication method based on NCWA were verified by the multi-scale finite element analysis and dynamic loading test on the Xinyihe Bridge.The results show that the locations of different scale damages can be identified by the method of NCWA without considering noise effects,and the damage sensitivity of small scale units is superior to big scale units.If considering noise effects,the locations of small damage scale can be identified approximately by NCWA,and the anti-noise ability of small scale units is superior to big scale units.The results support the idea that the proposed damage identification method based on NCWA has a great potential in the health monitoring of practical engineering structures,and it lays a solid foundation for the damage prognosis (DP)and safety prognosis (DP)of girder structures.%以新沂河大桥为工程背景,提出了一种基于节点曲率和小波分析(NCWA)的梁式桥多尺度损伤识别方法。首先基于结构弯矩-曲率基本关系和结构微损伤对其应力重分布影响很小的假定,结合小波分析的消噪功能,采用奇异值分解(SVD)方法求解节点曲率损伤前后的线形矩阵方程,推导了基于节点曲率的损伤指标,并通过简支梁试验验证了该方法的

  14. 大跨度公铁两用钢桁梁斜拉桥结构地震响应特征研究%Study of Structural Seismic Response Characteristics of Long Span Rail-cum-Road Steel Truss Girder Cable-Stayed Bridges

    Institute of Scientific and Technical Information of China (English)

    阮怀圣; 屈爱平; 何友娣; 苗润池; 李龙安

    2015-01-01

    大跨度公铁两用钢桁梁斜拉桥是一种技术复杂的特殊桥梁,为系统地把握该类型桥梁结构在地震作用下的动力响应规律,总结该类桥梁的总体结构特征,统计分析5座公铁两用大桥的结构动力特性值,利用有限元数值仿真方法分析不同结构抗震约束体系的地震响应特点,统计粘滞阻尼器的减震效果并解释效果差异的原因。研究表明:大跨度公铁两用斜拉桥的竖向刚度与公路斜拉桥相比有明显差异,前者的竖弯基频比后者平均高20%左右;在多种结构抗震约束体系中,具有耗能显著特点的液体粘滞阻尼器体系是一种较为理想的结构抗震支承体系;采用粘滞阻尼器后,6座大桥桥塔的弯矩减震率呈现20%左右与60%以上两种不同表现结果,该现象主要与地震动输入的长周期成分取值有关;由于剪力比弯矩的阶次低,导致桥塔剪力比弯矩的减震效果低;粘滞阻尼器对梁端位移的减震效果显著,可达到60%~80%。%T he long span rail‐cum‐road steel truss girder cable‐stayed bridge is a type of the special bridge of technical complexity . To systematically understand the structural dynamic re‐sponse law s of such type of the bridges under the action of earthquake ,the general structural char‐acteristics of the bridges were summed up and the structural dynamic characteristic values of 5 long span rail‐cum‐road steel truss girder cable‐stayed bridges were statistically analyzed .The seismic response characteristics of the different structural seismic restraint systems were analyzed ,using the finite element numerical simulation ,the damping effect of the fluid viscous dampers was statis‐tically collected and the differences of the damping effect were illustrated .The results of the analy‐sis demonstrate that the vertical stiffness of a long span rail‐cum‐road steel truss girder cable‐stayed bridge is

  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. The fatigue and serviceability limit states of the webs of steel girders subjected to repeated loading

    OpenAIRE

    M. Škaloud; Zörnerová, M. (Marie)

    2010-01-01

    As a great part of steel structures are subjected to many times repeated loads (bridges, crane-supporting girders and the like), it is demonstrated, by means of the results of numerous experiments carried out by the authors in Prague, how the post-critical reserve of strength, the failure mechanism and the limit states of the webs of steel girders are affected by the cumulative damage process generated by the many times repeated character of loading, and how this phenomenon influences the des...

  17. Composite Steel-Concrete Girders with Circular Holes

    OpenAIRE

    Feneşan, Crina; Moga, Cătălin

    2015-01-01

    In this paper some aspects concerning the design of steel-concrete composite structures are presented. The steel girders are built-up as rolled sections with circular holes in webs. This paper also presents, an adaptation of Euro norms EN 1994-1-1:2004. Eurocode 4 - Design of composite and concrete structures – Part 1-1: General rules for buildings and EN 1994-2:2004. Eurocode 4 - Design of composite and concrete structures – Part 2: General rules and rules for bridges to the design of comp...

  18. Research on Damage Identification for the Girders of Cable-stayed Bridges Based on Particle Swarm Optimization-support Vector Machine(PSO-SVM)%基于粒子群优化支持向量机的斜拉桥主梁损伤识别研究

    Institute of Scientific and Technical Information of China (English)

    赵世英; 李延强

    2015-01-01

    A new method of damage detection based on particle swarm optimization-support vector machine (PSO-SVM) is proposed in this paper in order to identify the girder damage of the cable-stayed bridge more ac-curately.The best kernel parameters for support vector machine(SVM) are obtained by particle swarm optimiza-tion(PSO) and the testing model of SVM is established.Taking the most sensitivity cable tension indexes as in-puts of SVM for both training and testing, damage locations of the main girder for cable-stayed bridge are indica-ted by the outputs of SVM.A numerical example for a test model of a single-tower cable-stayed bridge is provid-ed to verify the feasibility of the method.It is shown that the automatic optimization of the parameters for SVM can be realized by PSO algorithm and different kinds of damage of the girder for cable-stayed bridge can be de-tected and the identification efficiency is high.%为了能够更加准确地判断结构损伤位置和程度,本文提出了基于粒子群优化支持向量机(PSO-SVM)方法对斜拉桥主梁进行损伤识别的新方法。该方法以最敏感索张力指标作为损伤识别指标,利用粒子群(PSO)算法寻找支持向量机(SVM)最优参数,建立 SVM 预测模型,以不同位置、不同损伤程度下最敏感索的张力指标作为 SVM 的训练和测试输入,由 SVM 的输出确定损伤位置。通过对实验室的模型斜拉桥的主梁损伤进行了仿真验证,结果表明:采用 PSO 算法很好地解决了采用 SVM 方法进行损伤识别时的参数选择随机性难题,实现了对 SVM 模型参数的自动优化,基于 PSO-SVM 的损伤识别方法对斜拉桥主梁不同程度的损伤均有很高的识别率。

  19. Comparative Study for Buckling Resistance of Steel Sheets Provided with Stiffeners Used in Bridge Structures

    Directory of Open Access Journals (Sweden)

    Daraban Marian

    2015-09-01

    Full Text Available The subject discussed in this paper is based on an experimental bridge model which was built to study the pre-critical and post-critical buckling behaviour of steel webs of box girders provided with longitudinal and transversal stiffeners. The article presents a comparison between the experimental results and the numerical ones for buckling resistance of stiffened steel webs. For this purpose two types of analysis will be carried out: an analysis to establish the values and eigenvectors of buckling, after which the critical factor for the first mode of buckling will be obtained, and then a geometrical and physical nonlinear analysis will be performed.

  20. Trend of welding robot for bridge construction; Kyoryo ni okeru genba yosetsu no jidoka robot ka

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, O. [Takada Kiko Co. Ltd., Osaka (Japan)

    1997-12-01

    This paper explains general bridge construction methods and describes future problems therein on automation and robotization of site welding in bridge construction. Site jointing in bridge construction has used high-strength bolt jointing as the mainstream until recently, but adoption of site welding is now increasing. Steel bed plates, box girders, I-shaped girders, and bridge piers have different characteristic requirements in welding volume and plate thickness, to which carbon dioxide arc-welding and submerged-arc welding are used depending on welding postures. Anti-seismic reinforcement construction on RC bridges has started with the Great Hanshin Earthquake as a turning point (steel plates are wound round columns, welded by CO2 arc-welding using the backing strip system, and resin and/or mortar are filled into clearance between RC and the steel plates). This construction requires vertical welding work with welding length as long as 10 m or longer, making the automation and robotization great advantages. For all cases, robotization in site constructions has just begun, whereas a number of problems desired of solution on robots exist, such as high-efficiency welding, and weldable postures the robots can take. 1 ref., 13 figs.

  1. 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

  2. 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

    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 of the......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...

  3. Two bridges with composite prestressed tension chord

    OpenAIRE

    Muttoni, Aurelio

    2002-01-01

    the bridges over the river Capriasca (1996) and over the river Ticino (1997) are characterised by the application of an innovative structural system. The central part of the main span of both bridges is constituted by the bridge concrete deck with two longitudinal stiffening girders, constituted by polygonal steel members that contain two prestressing tendons each.

  4. 鸭绿江界河公路大桥主桥桥型方案比选%Comparison and Selection of Proposed Bridge Types for Main Bridge of Yalu Boundary River Highway Bridge

    Institute of Scientific and Technical Information of China (English)

    吴宏业; 于传君

    2013-01-01

    The Yalu Boundary River Highway Bridge is an important international project connecting China and DPR Korea. In the light of the actual project conditions at the bridge site, two proposed bridge types for the main bridge of the bridge were compared, i. e. a steel box girder cable-stayed bridge with double pylons and double cable planes (the span arrangement being (86 + 229 + 636 + 229 + 86) m and the pylons being the H-shape concrete structures to be cast in situ) and a steel and concrete composite girder cable-stayed bridge with double pylons and double cable planes (the span arrangement being (87 + 228 + 636 + 228 + 87) m and the pylons being the inverted Y-shape concrete structures to be cast in situ). The plane link program Doctor Bridge V3. 2. 0 was used to respectively set up the finite element models for the two bridge types, the global mechanical behavior of the two bridges at completion and operation stages were analyzed and the construction convenience, durability and economy were analyzed as well. The results of the analysis show that the structural mechanical behavior of the steel box girder cable-stayed bridge is more advantageous, the construction is more convenient, the construction time schedule is shorter and the seismic performance is better and therefore the box girder bridge having 5 spans, double pylons and double planes is finally selected.%鸭绿江界河公路大桥是连接朝鲜的跨国性重要工程,结合桥址处实际工程条件,选取双塔双索面钢箱梁斜拉桥[跨径布置为(86+229+636+229+86)m,采用现浇H形桥塔]和双塔双索面钢-混结合梁斜拉桥[跨径布置为(87+228+636+228+87)m,采用现浇倒Y形桥塔]2种桥型方案进行比选.采用平面杆系程序桥梁博士V3.2.0分别建立2种方案的有限元模型,按整体成型对桥梁成桥阶段及运营阶段进行整体受力分析,并对2种方案的施工便利性、耐久性及经济性进行对比分析.分析结果表明,钢箱梁斜拉桥结

  5. 液体粘滞阻尼器配合双曲面球型支座在大跨连续梁桥中的减隔震研究%Research on Seismic Isolation Technology of Fluid Viscous Damper with Double Spherical Seismic Bearing in Large-span Continuous Girder Bridge

    Institute of Scientific and Technical Information of China (English)

    李健宁; 虞庐松

    2016-01-01

    大跨度连续梁桥由于上部结构惯性力较大,导致传统延性抗震设计方法很难满足桥梁抗震性能需求,减隔震技术是解决这一问题的有效途径之一。采用液体粘滞阻尼器配合双曲面球型减隔震支座对某高烈度大跨连续梁桥进行了减隔震设计,结果表明:液体粘滞阻尼器减震效果明显,但固定墩地震力较大仍难以满足要求;采用双曲面球型减隔震支座,除边墩受地震力明显增大外其余墩较均匀的分担了地震荷载,墩身抗震性能充分发挥,且其具备自复位功能震后修复难度较低;液体粘滞阻尼器配合双曲面球型减隔震支座时减震效果明显优于仅设置阻尼器,且前者具备一定的自复位功能,与设置双曲面球型支座相比前者解决了边墩的抗震问题。本桥减隔震设计中此方法最优,该方法可为高烈度区大跨连续梁桥的抗震设计和抗震加固提供参考。%Because the inertial force of the superstructure of the large-span continuous girder bridge is larger,the traditional ductility seismic design method cannot meet the needs of seismic performance of bridge seismic design.The seismic isolation technology is one of the effective ways to solve the problem,so a large-span continuous girder bridge in a high intensity seismic area is taken as an example for seismic isolation design by adopting the fluid viscous damper with double spherical seismic bearing.The results show that the damping effect is obvious after using the damper,but it is still difficult to meet the requirements.In addition,it is hard to repair after the earthquake without the self-resetting function.After using the double spherical seismic bearing, the rest piers are increased to uniformly bear the earthquake load besides the side pier and give full play to the seismic behavior,and they are easy to repair after the earthquake with the self-re-setting function.However,when using fluid

  6. Effects of seismic devices on transverse responses of piers in the Sutong Bridge

    Science.gov (United States)

    Shen, Xing; Camara, Alfredo; Ye, Aijun

    2015-12-01

    The Sutong Bridge in China opened to traffic in 2008, and is an arterial connection between the cities of Nantong and Suzhou. It is a cable-stayed bridge with a main span of 1,088 m. Due to a tight construction schedule and lack of suitable seismic devices at the time, fixed supports were installed between the piers and the girder in the transverse direction. As a result, significant transverse seismic forces could occur in the piers and foundations, especially during a return period of a 2500-year earthquake. Therefore, the piers, foundations and fixed bearings had to be designed extraordinarily strong. However, when larger earthquakes occur, the bearings, piers and foundations are still vulnerable. The recent rapid developments in seismic technology and the performance-based design approach offer a better opportunity to optimize the transverse seismic design for the Sutong Bridge piers. The optimized design can be applied to the Sutong Bridge (as a retrofit), as well as other bridges. Seismic design alternatives utilizing viscous fluid dampers (VFD), or friction pendulum sliding bearings (FPSB), or transverse yielding metallic dampers (TYMD) are thoroughly studied in this work, and the results are compared with those from the current condition with fixed transverse supports and a hypothetical condition in which only sliding bearings are provided on top of the piers (the girder can move "freely" in the transverse direction during the earthquake, except for frictional forces of the sliding bearings). Parametric analyses were performed to optimize the design of these proposed seismic devices. From the comparison of the peak bridge responses in these configurations, it was found that both VFD and TYMD are very effective in the reduction of transverse seismic forces in piers, while at the same time keeping the relative transverse displacements between piers and the box girder within acceptable limits. However, compared to VFD, TYMD do not interact with the

  7. Nondestructive testing of lining of reinforced concrete bridges

    International Nuclear Information System (INIS)

    The distribution, course and profile of concrete reinforcement bars are found using a magnetic indicator or radiographically mostly using a 60Co radioactive source with an activity of 370 GBq to 1.11 TBq. With simple girder bridges the lower tension reinforcement is controlled in the centre of the span, slide reinforcement near the support, reinforcement in the slab and possibly reinforcement in the foundation sill, with continuous girder bridges the upper tension reinforcement is determined using stereoscopic photographing from two foci. For wider girders the sources are placed in holes drilled in the girders at a distance of 200 mm. The magnetic indicator of reinforcement is used for controlling slab bridges of less reinforced concrete while the radiographic method is used for monitoring bridges with thicker reinforcement. The distribution of reinforcement in cross section is monitored graphically by plotting the configuration at which the cross section was scanned. (E.S.)

  8. Comprehensive Real-Time Bridge Health Monitoring System of Tongtai Bridge

    OpenAIRE

    Lei Su-su; Gao Yong-tao; Pan Dan-guang

    2015-01-01

    Tongtai Bridge is the world’s largest suspension curve-girder-skew-arch bridge, which is located in Zhangjiakou, China. The understanding of mechanics characteristics is limited to such complex bridges, so it is necessary to establish reliable health monitoring system to investigate the static and dynamic responses and monitor the safety of the bridge. A comprehensive real-time bridge health monitoring system is establish, which includes four aspects: sensor system, data acquisition and trans...

  9. 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

  10. Analysis of Biaxially Stressed Bridge Deck Plates

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Bondum, Tommi Højer

    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 ...

  11. Long-Term Effects of Super Heavy-Weight Vehicles on Bridges

    OpenAIRE

    Wood, Scott M.; Akinci, Necip Onder; Liu, Judy; Bowman, Mark D

    2007-01-01

    A permit truck which exceeds the predefined limit of 108 kips is defined as a superload in Indiana. This study was conducted to examine the long-term effects of superload trucks on the performance of typical slab-on-girder bridges and to assess the likelihood of causing immediate damage. Typical steel and prestressed concrete slab-on-girder type bridges were analyzed using both beam line analysis and detailed finite element models. Furthermore, one prestressed concrete bridge and one steel br...

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

    OpenAIRE

    Tolosana, N.; Cuartero, J.; Chiminelli, A.; Comino, P.; Ranz, D.; Calvo, I.; Mieres, J. M.; Miravete, A.

    2006-01-01

    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 sev...

  13. The Influence of the Recommended LRFD Guidelines for the Seismic Design of Highway Bridges on Virginia Bridges

    OpenAIRE

    Widjaja, Matius Andy

    2003-01-01

    THE INFLUENCE OF THE RECOMMENDED LRFD GUIDELINES FOR THE SEISMIC DESIGN OF HIGHWAY BRIDGES ON VIRGINIA BRIDGES by Matius A. Widjaja Committee Chairwoman: Prof. Carin Roberts-Wollmann Civil Engineering (ABSTRACT) The influence of the recommended LRFD Guidelines for the seismic design of highway bridges in Virginia was investigated by analyzing two existing bridges. The first bridge has prestressed concrete girders and is located in the Richmond area. The second bridge has...

  14. 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...

  15. Design of Main Bridge of Hanbei River Jingling Bridge%汉北河竟陵大桥主桥连续梁设计

    Institute of Scientific and Technical Information of China (English)

    严少波

    2014-01-01

    汉北河竟陵大桥主桥是一座为7跨预应力混凝土连续箱梁桥,桥跨布置为40 m+5×70 m+40 m。结合该桥的设计过程,探讨了该桥的技术标准、结构设计、结构计算、耐久性设计和主要施工方法,从材料、构造措施和施工工艺等方面进行了设计以保证大桥的使用寿命。%Hanbei River Jingling Bridge is a seven span prestressed concrete continuous box girder bridge with the bridge spans arrangement of 40 m+5×70 m+40 m.In accordance with the process of the design of the bridge,this paper discusses the technical standards,structure design,structure calculation,durability design and the main con-struction method.The durability of the bridge is appropriately designed by the rational utilization of materials and structural formation so as to eventually ensure the long-term service life of the bridge.

  16. 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.

  17. 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.

  18. 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

  19. Nonlinear Seismic Response Analysis of Curved and Skewed Bridge System with Spherical Bearings

    OpenAIRE

    Linzell, Daniel G.; Junwon Seo; Jong Wan Hu

    2013-01-01

    A three-dimensional (3D) modeling approach to investigate nonlinear seismic response of a curved and skewed bridge system is proposed. The approach is applied to a three-span curved and skewed steel girder bridge in the United States. The superstructure is modeled using 3D frame elements for the girders, truss elements for the cross-frames, and equivalent frame elements to represent the deck. Spherical bearings are modeled with zero-length elements coupled with hysteretic material models. Non...

  20. Self-compacting concrete for prestressed bridge girders

    Science.gov (United States)

    Erkmen, Bulent

    The purpose of this study was to examine social mobility as a motivation for first-generation college students in reaching attainment at two-year technical colleges. The research question was to what degree has the perception of social mobility influenced first generation college students at technical colleges to complete their career educational goals. Graduates of a two-year technical college were asked a series of open-ended questions regarding their past experiences and perceptions of attending and completing a two-year technical college program; their childhood perceptions of their social status; and experiences with family members regarding their change in social class status. These questions were designed to determine their feelings, viewpoints, reflections, experiences, struggles, and thoughts about attainment (completing their post-secondary education) and the extent to which social mobility influenced their decision to complete their education. The benefits of this research include an understanding of social mobility and educational attainment. Results of this study could be used to better understand the process that first generation college students go through in order to attain their educational goals. The information from this study may be useful for technical college administrations to help design programs and processes for future first-generation college students' success and aid in retention of these students.

  1. Effects of CFRP Strengthening on Dynamic and Fatigue Responses of Composite Bridge

    Directory of Open Access Journals (Sweden)

    Kittisak Kuntiyawichai

    2014-01-01

    Full Text Available This paper investigates the effect of CFRP strengthening on dynamic and fatigue responses of composite bridge using finite element program ABAQUS. Dynamic and fatigue responses of composite bridge due to truck load based on AASHTO standard are investigated. Two types of CFRP strengthening techniques, CFRP sheets and CFRP deck, are applied to both the damaged and undamaged bridges. For the case of damaged bridge, two through-thickness crack sizes, 3 mm and 6 mm in depth, are assumed at midspan of the steel girders. Furthermore, effects of the number of steel girders on the dynamic and fatigue responses are also considered. The results show that the maximum responses of composite bridges occur for dual lane cases. By using CFRP as a strengthening material, the maximum stress and deflection of the steel girders reduce and consequently increase the fatigue life of the girders. After introducing initial crack into the steel girders of the composite bridges, the fatigue life of the bridges is dramatically reduced. However, the overall performance of the damaged composite bridge can be improved by using CFRP, albeit with less effectiveness. Therefore, if cracks are found, steel welding must be performed before strengthening the composite bridge by CFRP.

  2. Critical Strength of steel Girder Web

    OpenAIRE

    Pratibha M Alandkar; Sandeep M Shiyekar; Mukund R Shiyekar

    2016-01-01

    When a member is subjected to combined action of bending moment, shear and axial force, bending moment & axial force is assumed to resist by whole section and shear is resisted by web only. In such case web shall be designed for combined shear and axial force. The present study determines the strength of web of steel girder under the action of pure shear, pure axial force and combination of it. The classical plate buckling theory is already established to determine the critical buckling st...

  3. 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. 

  4. Influence of the new LRFD seismic guidelines on the design of bridges in Virginia

    OpenAIRE

    M.A. Widjaja; Roberts-Wollmann, Carin L.

    2004-01-01

    The Virginia Department of Transportation is currently using the AASHTO Standard Specifications for Highway Bridges, with some modifications, for its seismic highway bridge design. In April 2001, the Recommended LRFD Guidelines for the Seismic Design of Highway Bridges were published. The influence of the LRFD Guidelines on Virginia bridges was investigated by analyzing two existing bridges. The first bridge has prestressed concrete girders and is located in the Richmond area. The second brid...

  5. 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 to...... the direction of the wind and occur when the bridge is exposed to wind velocity above critical value called the flutter wind velocity Ucr....

  6. 大门大桥引桥过桥管线作用效应研究%Study of Action Effect of Pipelines Across Approach Bridge of Damen Bridge

    Institute of Scientific and Technical Information of China (English)

    庄小将; 马芹刚; 王丰平; 庄庆华; 周海旺

    2011-01-01

    To study the degree of the influence of pipelines across bridge on the working performance of the bridge itself, the approach bridge (a continuous box girder bridge) of the Damen Bridge in Wenzhou City was cited as an example. On the basis of comparison of the different pipeline layout schemes, it was determined that the layout scheme of special zones for the pipelines on both sides of the deck of the bridge should be adopted and the dynamic and static force analysis and study were made for the influence of the pipelines on the bridge structure. The results of the analysis and study indicate that the midspan deflection of the bridge caused by the water load can be ignored as compared to the midspan deflection subjected to the short-term load combination. Thoughthe fluctuation ranges of natural frequency of the continuous girder structure of the bridge and constant flow frequency in the pipelines are different, the two kinds of the frequencies do not result in resonance. The stress increment in normal section of the bridge caused by the water load is less than 1 Mpa, which will be not enough to influence the safe operation of the bridge.%为了研究过桥管线对桥梁工作性能的影响程度,以温州市大门大桥工程引桥(连续箱梁桥)为工程背景,通过对管线布置方案的比选,确定该桥采用桥面两侧“管线专用区域”的布置方案;并就输水管道对桥梁结构的影响进行静、动力分析研究.研究表明,水荷载引起的桥梁跨中挠度与荷载短期效应组合下跨中挠度相比,可以忽略;连续梁结构的固有频率与输水管道内恒定流频率的波动范围不同,二者不会产生共振现象;水荷载引起的桥梁结构正截面应力增量小于1 MPa,不足以影响桥梁的安全运营.

  7. 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.

  8. Shear design recommendations for stainless steel plate girders

    OpenAIRE

    Saliba, Najib; Real, E.; Gardner, Leroy

    2014-01-01

    The behaviour and design of stainless steel plate girders loaded in shear is investigated in this paper. A review of existing methods for the design of stainless steel plate girders, including codified provisions, is first presented. A database of thirty-four experiments carried out on austenitic, duplex and lean duplex stainless steel plate girders is then reported, and used to assess the current shear resistance design equations from Eurocode 3: Part 1.4 and Eurocode 3: Part 1.5 and the rec...

  9. 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

  10. 悬臂施工波形钢腹板组合梁桥施工工艺%The cantilever construction of corrugated steel webs in bridge construction technique

    Institute of Scientific and Technical Information of China (English)

    曾强; 彭更生; 杜亚江

    2013-01-01

    The Fourth Nanjing Yangtze River Bridge north line of Chuhe bridge using web PC composite box girder bridge with corrugated steel. This type of bridge is a kind of high efficient,economic,simple con-struction of the new bridge form. This type of bridge,appropriately to steel,concrete of two different materials together,improves the intensity and stability of material structure,the usage efficiency. The bridge construction can provide a reference for the construction of the same type bridge.%  南京长江第四大桥北接线滁河特大桥采用波形钢腹板预应力混凝土组合箱梁桥。该类型桥是一种高效、经济、施工简便的新型桥梁形式。该类型桥恰当地将钢和混凝土两种不同材料结合起来,提高了结构稳定性、强度及材料的使用效率等。该桥的施工可为同类型桥的施工提供参考。

  11. Dynamic analysis of sliding behavior of curved bridge superstructure caused by horizontal ground motion; Suihei jishindo ni yoru kyokusenkyo jobu kozo no ido kyodo kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, H. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Kanda, M. [Ministry of Construction, Tokyo (Japan); Suzuki, M. [Tohoku University, Sendai (Japan); Yoshizawa, T. [Nippon Engineering Consultant Co. Ltd., Tokyo (Japan)

    1997-07-21

    It is observed often in the past earthquakes that the curved bridge tends to move to the radial direction of its curved bridge line when large seismic movement occurs and the bearings are broken. The rigid body movement of the curved girder which affects the sliding behavior is estimated. Some cases of dynamic nonlinear analysis to simulate the movement of bearing damaged curved bridge, and the parametric study to examine the dynamic characteristics of curved bridges are carried out. Based on the relationship between the traveling of girder and the various parameters of girder shape, the equation to calculate the length of the girder on the pier for curved bridges is estimated. 7 refs., 19 figs., 4 tabs.

  12. 结合梁桥面系异形钢箱拱肋系杆拱桥设计%Design of Special-shaped Steel Box Arch Rib Bowstring Arched Bridge of Bonding Beam Deck System

    Institute of Scientific and Technical Information of China (English)

    李文勃

    2009-01-01

    The main bridge of Putian Chenggang Avenue Bridge crossing Molan River is the special-shaped bowstring arched bridge of 2-span simple-supported double-rib half-through steel box arch rib bonding beam deck system. The single span is 72 m long and the bridge is 47.5 m wide with city-Class A load and double-direction of 8 lanes. Taking the preliminary design and construction drawing design of this bridge as the basis, the article introduces the scheme study of bridge type, structural design of main bridge and analysis of structural calculation of the special-shaped bowstring arched bridge, and analyzes some technical characteristics of this bridge. The design method of the main bridge inclined crossed with the curve river, the design thinks of bonding beam in the arched bridge, the temporary constructed supporting point for improving the structural bearing, and the design method of special arch rib modeling can be referred for the design of the similar bridges.%莆田城港大道跨木兰溪大桥主桥是两跨简支的双肋下承式钢箱拱肋结合梁桥面系的异形系杆拱桥,单跨跨径72m,桥宽47.5m,城一A级荷载,双向8车道.该文以该桥的初步设计和施工图设计为基础,介绍了异形系杆拱桥的桥型方案研究、主桥结构设计、结构计算分析等内容,并分析了该桥的一些技术特点.该桥的弯曲河道斜交主桥设计方法、结合梁在拱桥中的设计思想、结合梁横梁设置临时支点改善结构受力、独特拱肋造型的设计方法等内容,可供类似桥梁设计时参考.

  13. Hybrid networking sensing system for structural health monitoring of a concrete cable-stayed bridge

    Science.gov (United States)

    Torbol, Marco; Kim, Sehwan; Chien, Ting-Chou; Shinozuka, Masanobu

    2013-04-01

    The purpose of this study is the remote structural health monitoring to identify the torsional natural frequencies and mode shapes of a concrete cable-stayed bridge using a hybrid networking sensing system. The system consists of one data aggregation unit, which is daisy-chained to one or more sensing nodes. A wireless interface is used between the data aggregation units, whereas a wired interface is used between a data aggregation unit and the sensing nodes. Each sensing node is equipped with high-precision MEMS accelerometers with adjustable sampling frequency from 0.2 Hz to 1.2 kHz. The entire system was installed inside the reinforced concrete box-girder deck of Hwamyung Bridge, which is a cable stayed bridge in Busan, South Korea, to protect the system from the harsh environmental conditions. This deployment makes wireless communication a challenge due to the signal losses and the high levels of attenuation. To address these issues, the concept of hybrid networking system is introduced with the efficient local power distribution technique. The theoretical communication range of Wi-Fi is 100m. However, inside the concrete girder, the peer to peer wireless communication cannot exceed about 20m. The distance is further reduced by the line of sight between the antennas. However, the wired daisy-chained connection between sensing nodes is useful because the data aggregation unit can be placed in the optimal location for transmission. To overcome the limitation of the wireless communication range, we adopt a high-gain antenna that extends the wireless communication distance to 50m. Additional help is given by the multi-hopping data communication protocol. The 4G modem, which allows remote access to the system, is the only component exposed to the external environment.

  14. 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.

  15. 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.

  16. BENDING-SHEAR INTERACTION OF LONGITUDINALLY STIFFENED GIRDERS

    OpenAIRE

    Beg, Darko; Sinur, Franc

    2011-01-01

    To understand behaviour of longitudinally stiffened plated girders subjected to high bending moments and shear forces, four tests on large scale test specimens were performed. The results of these tests were used to verify the numerical model, which was employed for further parametric studies. With a verified simplified numerical model a parametric nonlinear analysis was systematically carried out to determine the resistance of longitudinally stiffened plated girders. Based on 630 numerical s...

  17. 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...

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

    DEFF Research Database (Denmark)

    Hansen, Henriette I.; Thoft-Christensen, Palle

    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 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...... 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....

  19. 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.

  20. An innovative steel-concrete joint for integral abutment bridges

    OpenAIRE

    Bruno Briseghella; Tobia Zordan

    2015-01-01

    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 b...

  1. 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

  2. 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

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

    Directory of Open Access Journals (Sweden)

    Ruicong Han

    2016-07-01

    Full Text Available 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.

  4. 跨104国道特大桥84m钢桁梁高位拼装悬臂顶推架设施工技术%High Position Erection of 84m Steel Truss Girder Super-large Bridge Crossing National Highway No.104 by Catilever Method through Pushing

    Institute of Scientific and Technical Information of China (English)

    张锐光; 彭洪波

    2011-01-01

    This article introduces the process of erecting 84m steel truss girder at high position by cantilever method. Steel-pipe columns, elements for military pier 83, Bailey elements were adopted to construct a temporary platform, intermittent chute and continuous gliding chute were designed, beam 87 elements were assembled to form a long guiding beam, jack ZLD150 was adopted for continuous pushing, the erection of steel truss girder was completed. During construction the existing national road traffic was not affected, safety, fast and efficient construction was achieved.%对84 m钢桁梁高位拼装悬臂顶推架设施工过程的研究,旨在总结出一套成熟的施工方法.着重介绍84 m钢桁梁项推施工过程中利用钢管柱、军用八三墩杆件、贝雷梁搭设临时施工平台,采用间断性上滑道,连续性下滑道的设计,通过八七梁杆件组拼的长导梁及ZLD150型千斤顶连续顶推的施工方法,完成了钢桁梁架设.施工过程中未对既有国道行车造成任何影响,具有施工安全、快速、高效的特点.

  5. Study of Shear Stud Connector Layout for Composite Girders%结合梁剪力钉布置形式研究

    Institute of Scientific and Technical Information of China (English)

    侯健; 罗扣

    2014-01-01

    为提高结合梁桥桥面板的整体性,并方便施工,对剪力钉集束式(在钢梁腹板的上翼缘每隔一定距离布置1束剪力钉群,各钉群之间留有相应宽度无钉区)布置形式进行研究。通过建立结合梁结构的有限元模型,分别计算恒载、车辆偏载作用下,集束式和均布式(钢梁上翼缘均匀、等间距的剪力钉布置形式)桥面板和剪力钉的滑移量、钢梁的应力、钢梁底板位移等。研究结果表明:剪力钉集束式布置具有桥面板整体性好,施工工序简单等特点;在荷载作用下,剪力钉采用集束式布置能够保证钢梁和混凝土桥面板之间有效传力;汽车偏载作用下,集束式布置也可以保证钢梁与混凝土桥面板之间的有效结合,不会发生桥面板上掀现象。%In order to improve the integrity of the deck of composite girder bridge and for the convenience of construction ,the clustered shear stud connectors arrangement was studied (in the upper flange of the webs of the steel girder ,clusters of shear stud connectors are installed with e-qual intervals and a connector-free zone with certain width among the clusters is reserved ) .The fi-nite element model of the composite girder structure was established to calculate respectively the slip amount of the bridge deck and shear stud connectors ,stress in the steel girder and the dis-placement of the steel girder base plate under the action of dead load and eccentric vehicle load ,for both the clustered arrangement and uniform arrangement (the shear stud connectors are uniformly arranged in the upper flange of the steel girder with equal intervals ) .The results of the study dem-onstrate that the clustered arrangement of shear stud connectors is favorable for the integrity of the bridge deck and simplifies the construction procedures ;under the action of loads ,the clustered ar-rangement of shear stud connectors allows the effective force

  6. Stress analysis of the welds in the girder

    International Nuclear Information System (INIS)

    The girder at the back of each module plays an important structural role in the assembly of the Tilecalorimeter barrel. It is important, therefore, to clearly understand the welds within the girder. In order to understand the stresses in the welds, a 2-dimensional finite element model has been constructed of the girder cross section similar to the model that has been previously used by J. Blocki to analyze the girder. The current European welding norms do not require stress concentrations within welds to be considered except under fatigue loading conditions. Since this is not the case for this design, the use of the average stress in sizing the welds is allowed under the European welding norms. An analysis of the welds by V. Romanov that only considered the average stress, showed that the average weld stress was 38N/mm2, well within acceptable limits. However, it should be kept in mind that the forces on the welds vary significantly along the length of the girder so the average stress may not be an adequate method of analyzing these welds. In addition, since these welds are so critical to the structural integrity of the Tilecalorimeter, it is desirable to examine stress concentrations even though this is not required by the european norms. Therefore, it is recommended that a 30mm wide bar as shown in Figure 3 be used on the ten modules that see the highest load from the cryostat. This is a very simple and low-cost modification to a small number of girders that will provide significant additional safety

  7. 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...... 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....

  8. 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.

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

    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 .

  10. 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.

  11. Geometric nonlinear analysis of self-anchored cable-stayed suspension bridges.

    Science.gov (United States)

    Hui-Li, Wang; Yan-Bin, Tan; Si-Feng, Qin; Zhe, Zhang

    2013-01-01

    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. PMID:24282388

  12. Experiments and theory on deck and girder crushing

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup; Ocakli, Hasan

    1999-01-01

    This paper is concerned with theoretical and experimental analysis of deep plastic collapse of a deck or deep girder subjected to an in-plane, concentrated load. A theory is derived which is valid until initition of fracture in the structure. The presented experimental results show load-deflectio...

  13. General Construction Scheme for Anqing Changjiang River Railway Bridge%安庆长江铁路大桥总体施工方案

    Institute of Scientific and Technical Information of China (English)

    农代培; 季跃华; 徐炳法

    2013-01-01

    安庆长江铁路大桥采用双塔三索面钢桁梁斜拉桥和6孔64 m跨现浇简支箱梁布置形式,铁路4线.深水区3号、4号桥塔墩采用先围堰后平台的双壁钢围堰施工方案;5号墩桩基采用定位桩平台施工方案,承台采用双壁钢围堰施工方案.浅水区6号、7号及W01号、W02号桥墩桩基采用双栈桥加定位桩平台施工方案,承台采用钢板桩围堰施工方案.桥塔起始段采用支架法施工,其余采用大节段液压爬模施工;横梁采用支架法施工,分2层浇注.主桥无索区钢梁采用膺架法架设,桥塔墩有索区钢梁采用架梁吊机对称伸臂架设;在3号墩设置桁内开启式提升站取梁;全桥设2个合龙口,先中跨、后边跨合龙.非通航孔桥64 m箱梁采用支架法现浇施工.水中墩平台、围堰及栈桥考虑不同设防水位.该桥已于2012年12月实现多点精确合龙.%Anqing Changjiang River Railway Bridge was arranged as a 4-track railway steel truss girder cable-stayed bridge with double pylons,triple cable planes and with 6 spans of 64-m cast-in-situ simply-supported box girders.The pylon piers No.3 and No.4 of the bridge in the deep water area were constructed by the scheme of double-wall steel cofferdams,in which the cofferdams were set up first and the working platforms were late.The pile foundation of the pier No.5 was constructed by the positioning pile platform and the pile cap of the pier was constructed by the double-wall steel cofferdam.The pile foundations of the piers No.6,No.7 and the piers W01 and W02 in the shallow water area were constructed by the twin trestle bridges and positioning pile platforms and the pile caps thereof were constructed by the steel sheet pile cofferdams.The starting segments of a pylon were constructed by the scaffolding method while the rest of the segments were constructed by the large segment hydraulic climbing formwork.The cross beam of the pylon was cast in two layers by the scaffolding method

  14. Comparison of Internal and External Prestressing for Typical Highway Bridges

    OpenAIRE

    BURDET, Olivier; Badoux, Marc

    2000-01-01

    The paper presents an analytical comparison of the amount of prestressing required for two similar bridges, one with internal and the other with external prestressing. This comparison shows that bridges with external prestressing can become economically competitive for large girder depths. The detrimental effect of the smaller stress in the prestressing steel at the ultimate limit state is more than compensated by the thinner webs made possible by the absence of the ducts.

  15. The Aronda "Black Box" - Bridging the Gap of Mistrust in Insurance Service Relationships : A Study of Damage Adjustment as a Critical Episode

    OpenAIRE

    Kumassah, William; Mujcinovic, Mevludin

    2010-01-01

    Problem: The nature of insurances, and indeed the customer-provider relationship in insurance services, lends itself to distinctive characteristics. These characteristics have particular implications on overall perceived service and relationship quality, and thus customer retention. The arguably singular characteristic of mutual mistrust prevalent in insurance service relationships, is a source for costs and lost profitability for insurance companies in Sweden. Bridging the “gap of mistrust”,...

  16. TMD-Based Structural Control of High Performance Steel Bridges

    International Nuclear Information System (INIS)

    The purpose of this study is to investigate the effectiveness of structural control using tuned mass damper (TMD) for suppressing excessive traffic induced vibration of high performance steel bridge. The study considered 1-span steel plate girder bridge and bridge-vehicle interaction using HS-24 truck model. A numerical model of steel plate girder, traffic load, and TMD is constructed and time history analysis is performed using commercial structural analysis program ABAQUS 6.10. Results from analyses show that high performance steel bridge has dynamic serviceability problem, compared to relatively low performance steel bridge. Therefore, the structural control using TMD is implemented in order to alleviate dynamic serviceability problems. TMD is applied to the bridge with high performance steel and then vertical vibration due to dynamic behavior is assessed again. In consequent, by using TMD, it is confirmed that the residual amplitude is appreciably reduced by 85% in steady-state vibration. Moreover, vibration serviceability assessment using 'Reiher-Meister Curve' is also remarkably improved. As a result, this paper provides the guideline for economical design of I-girder using high performance steel and evaluates the effectiveness of structural control using TMD, simultaneously.

  17. Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N⁴-methyl-3-thiosemicarbazone: crystal structure of a novel sulfur bridged copper(II) box-dimer.

    Science.gov (United States)

    Jayakumar, K; Sithambaresan, M; Aiswarya, N; Kurup, M R Prathapachandra

    2015-03-15

    Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N(4)-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ=0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g||>g⊥>2.0023 and the g values in frozen DMF are consistent with the d(x2-y2) ground state. The thermal stabilities of some of the complexes were also determined. PMID:25546494

  18. Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N4-methyl-3-thiosemicarbazone: Crystal structure of a novel sulfur bridged copper(II) box-dimer

    Science.gov (United States)

    Jayakumar, K.; Sithambaresan, M.; Aiswarya, N.; Kurup, M. R. Prathapachandra

    2015-03-01

    Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N4-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ = 0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)sbnd I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g|| > g⊥ > 2.0023 and the g values in frozen DMF are consistent with the dx2-y2 ground state. The thermal stabilities of some of the complexes were also determined.

  19. Line type control for construction of a basket-style tied bars arch bridge%某提篮式系杆拱桥施工过程的线形控制

    Institute of Scientific and Technical Information of China (English)

    莫增模

    2015-01-01

    以广州市南沙区凤凰三桥为工程背景,针对该桥拱肋拼装后整体吊装,主梁悬臂拼装的特殊施工过程,精确计算其钢箱拱及钢箱梁的三大线形(成桥线形、安装线形、预拼线形),结合具体的施工方法,揭示了三大线形之间的内部转化关系以及各种线形与施工方法的关联性。%This article took the third Fenghuang bridge located in Nansha district Guangzhou as engineering background. After the bridge arch rib assembly for lifting the overall and the main beam cantilever erection of special construction process,calculate accurately line type( line type of sus-pension bridge,alignment line type,preassembly line type)of the steel box arch and steel box girder. Contacting the specific construction methods, reveal internal transformation of the relationship between the three line type and the correlation of a variety of line type and construction methods.

  20. Experimental Research on Dynamic Characteristics of Cable- stayed Bridge of Liaohe River Grand Bridge of Coastal Highway%滨海公路辽河特大桥斜拉桥动力特性试验研究

    Institute of Scientific and Technical Information of China (English)

    邓昌宁

    2012-01-01

    Taking the part of cable - stayed bridge of Liaohe River Grand Bridge of coastal highway of Liaoning province as an example, the method of utilizing ansys finite element software to make theoretical analysis on dynamic characteristics of cable - stayed bridge with double tower and double cable steel box girder is introduced, and technical points of dynamic test like field modal test ( pulsation test) of large bridge, slide down, vehicle jump, brake and so on are researched. Through the analysis and comparison of theoretical calculation value and field test result, it shows that the bridge has good dynamic behavior of structure and better wind - resistant stability. Under the effect of general vehicle load, the bridge has good character of service without stress and resonance phenomenon.%以辽宁省滨海公路辽河特大桥斜拉桥部分为例,介绍了利用ansys有限元软件进行双塔双索面钢箱梁斜拉桥动力特性理论分析的方法,研究了大型桥梁现场模态测试(脉动试验)、跑车、跳车、刹车等动态试验的技术要点,通过对理论计算值与现场测试的结果进行分析比较,表明该桥具有良好的结构动力特性,抗风稳定性较好,在常规车辆荷载的作用下,不易出现受迫共振现象,具有良好的使用性能。

  1. CAD/CAM welding robot system in steel bridge panel fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Sugitani, Y.; Kanjo, Y.; Murayama, M. [NKK Corp., Tokyo (Japan)

    1995-02-05

    The CAD/CAM welding robot system for steel bridge panel fabrication is reported. The system is composed of two box girder panel sub-assembly lines, one exclusively for web panels and the other for flange panels, and all of the line equipment is controlled through a central control room. A total of 14 articulated-type robots are adopted in the welding stages including reinforcement by stiffener and fillet welding. By adopting a high-speed rotating arc welding process, a welding efficiency is nearly two times as high as that of conventional welding processes, and panel deformation is considerably small because of lower welding heat input. The welding robot system is stable with higher accuracy by use of newly developed joint end and bead end sensing techniques as well as a seam tracking arc sensor system based on the high-speed rotating arc. Through LAN, all of the welding robots are linked to the teachingless CAD/CAM system newly developed for steel bridge fabrication. 6 refs., 22 figs., 5 tabs.

  2. Strategies for Seismic Assessment of Common Existing Reinforced Concrete Bridges Typologies

    OpenAIRE

    Morbin, Riccardo

    2013-01-01

    This study concerns a new probabilistic framework to evaluate road/railway bridges after an earthquake by means of analytical fragility curves and inspections on the structure. In particular, the assessment is performed on existing reinforced concrete (RC) bridges with a common structural scheme in Italy (multi-span simply supported girder bridges). The framework is set up of 6 steps and each step is investigated. Steps 1 and 2 are a sort of preliminary work before the seismic event occurs: t...

  3. Critical traffic loading for the design of prestressed concrete bridge

    International Nuclear Information System (INIS)

    A study has been carried out to determine critical traffic loadings for the design of bridge superstructures. The prestressed concrete girder bridge already constructed in Lahore is selected for the analysis as an example. Standard traffic loadings according to AASHTO (American Association of State Highway and Transportation Officials) and Pakistan Highway Standards are used for this purpose. These include (1) HL-93 Truck, (2) Lane and (3) Tandem Loadings in addition to (4) Military tank loading, (5) Class-A, (6) Class-B and (7) Class-AA loading, (8) NLC (National Logistic Cell) and (9) Volvo truck loadings. Bridge superstructure including transom beam is analyzed Using ASD and LRFD (Load and Resistance Factor Design) provisions of AASHTO specifications. For the analysis, two longer and shorter spans are selected. This includes the analysis of bridge deck; interior and exterior girder; a typical transom beam and a pier. Dead and live loading determination is carried out using both computer aided and manual calculations. Evaluation of traffic loadings is done for all the bridge components to find out the critical loading. HL-93 loading comes out to be the most critical loading and where this loading is not critical in case of bridge decks; a factor of 1.15 is introduced to make it equivalent with HL-93 -Ioading. SAP-2000 (Structural Engineering Services of Pakistan) and MS-Excel is employed for analysis of bridge superstructure subjected to this loading. Internal forces are obtained for the structural elements of the bridge for all traffic loadings mentioned. It is concluded that HL-93 loading can be used for the design of prestressed concrete girder bridge. Bridge design authorities like NHA (National Highway Authority) and different cities development authorities are using different standard traffic loadings. A number of suggestions are made from the results of the research work related to traffic loadings and method of design. These recommendations may be

  4. The mechanics of ship impacts against bridges

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    1998-01-01

    information is introduced in a mathematical model for estimation of the return period for collisions with bridge piers and girders. A new mathematical model is thereafter presented for calculation of the energies released for crushing of structures given a specific collision scenario which may include a...... glancing blow between the ship and the bridge structure. This model is based on rigid body mechanics and well suited for inclusion in a probabilistic analysis procedure. Finally, some empirical expressions are presented which relate the energy absorbed by crushing of ship structures to the maximum impact...

  5. 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....

  6. 双斜塔钢箱梁斜拉桥抗风性能试验研究%Experimental investigation on wind-resistant behavior of double pylon cable stayed bridge with steel box beam

    Institute of Scientific and Technical Information of China (English)

    马存明; 陈勉; 王玉柱; 高伟

    2011-01-01

    In order to evaluate wind-resistant behavior of a double pylon cable stayed bridge with steel box beam, dynamic response characteristics of the bridge were analyzed. The aerostatic force coefficient, the critical wind velocity of vibration and vortex-induced vibration response were measured using the combined method of numerical analysis and wind tunnel test, to assess wind-resistant behavior of the bridge. The results showed that the aerodynamic and flutter stability characteristics were good, but there were two obvious vertical vortex-induced resonance regions, and the peak excursion was much larger than the allowable value. Therefore, the bridge needs an aerodynamic shape optimization to reduce or control vortex-induced vibration. By comparing a variety of optimization solutions given by vortex-induced vibration experiments, the most optimized measure for vortex-induced vibration control was to add a fair water fin of 1m wide and 30° incline to the bottom slab.%为了评价某拟建大跨度双斜塔钢箱梁斜拉桥的抗风安全性能,通过数值分析与风洞试验相结合的方法研究其结构动力特性,测定静力三分力系数、颤振临界风速和涡激振动响应,据此分析评估该桥的抗风性能.结果表明,该桥具有较好的气动和颤振稳定性,但存在两个明显的竖向涡激共振区,且最大振幅远超过规定容许值.因此,该桥需要通过气动外形优化,以减小或控制涡激振动.经多种主梁涡激振动性能优化方案对比试验得出其最优措施为轨道内侧增加一条宽1m、与底板夹角成30°的导流板.

  7. Model test study of the static property of the Jiangdong Bridge in Hangzhou%杭州江东大桥静力特性全桥模型试验研究

    Institute of Scientific and Technical Information of China (English)

    沈锐利; 齐东春; 唐茂林

    2011-01-01

    杭州江东大桥是一座独柱桥塔、空间缆索、分离式钢箱、单跨悬吊、主梁宽达47m的自锚式悬索桥.按照几何缩尺比1:16、力缩尺比1:4的相似比设计了全桥试验模型,利用试验模型研究了结构成桥后的静力力学特性.试验测试r结构的影响线,并根据影响线确定最不利弯矩的加载区间,全面研究了结构在多种工况下的结构行为.试验与理论研究表明,成桥后结构的受力行为基本是线弹性的,可以用线弹性理论进行分析;薄壁、宽箱梁存在明显的剪力滞效应,箱梁截面的应力分布和变形受剪力滞影响较大,主缆和吊索内力受箱梁剪力滞的影响较小.%The Jiangdong Bridge in Hangzhou is a spatial cable self-anchored suspension bridge, width 47m, singlecolumn pylon, separate steel box and single-span suspension. A total bridge model is designed with a geometric scale of 1:16 and a force scale of 1:4, and the structural static property in service stage is studied using model test. Influence lines of internal force and displacement, and the corresponding loading interval for maximum moment are determined.Structural behavior in different situations is thoroughly studied. Test and theoretical analysis show that structural mechanical property is linear for the completed bridge. There exists shear lag effect in the thin-wall wide box girder,which obviously impacts the stress and deformation of the box girder, but the influence on internal forces of the main cables and hangers is quite small.

  8. Vortex-induced vibration of a suspension bridge with central-slotted box section and its control test study%桥面中央开口悬索桥涡激共振与制涡试验研究

    Institute of Scientific and Technical Information of China (English)

    欧阳克俭; 陈政清; 韩艳; 李红利

    2009-01-01

    Vortex-induced vibration (VIV) of a suspension bridge with central-slottod box section and its control was studied by use of wind tunnel test. The conversion relationships between the resonant amplitudes of the model and those of the prototype bridge were considered. And the correction coefficients of modal shapes were also presented. Two methods were proposed to control VIV successfully. The second method was able to control VIV effectively under the condition that the section shape was not altered and it could meet the requirements of engineering practice. The test al- so indicated that damping could suppress the amplitudes of VIV notably.%研究了中央开口断面悬索桥涡振及其控制风洞试验.考虑了模型涡振幅值和和实桥涡振幅值之间换算的修正系数,风洞试验表明中央开口是导致该种断面形式涡激振动发生的主要原因.所设计的两种制涡方案都能达到控制涡振的目的,在不改变断面形式等因素的前提下,设计的制涡方案二能有效控制涡振,符合工程实际要求.同时试验也表明,阻尼能大幅降低涡振幅值.

  9. 城市轨道交通双线桥上无缝线路挠曲力研究%Analysis of the Flexural Forces in CWR on Double-track Bridges of Urban Rail Transit

    Institute of Scientific and Technical Information of China (English)

    王冬梅; 倪向阳; 王慧珺

    2012-01-01

    针对城市轨道交通中新应用的双线U型梁和传统的双线箱型梁两种不同形式桥梁,用有限元法计算分析桥上无缝线路附加挠曲力及附加挠曲位移的分布,着重研究线路纵向阻力、桥梁跨度和桥墩刚度等参数变化对桥上无缝线路钢轨受力、桥墩受力及桥梁挠度的影响.研究结果表明,线路纵向阻力、桥梁跨度对钢轨挠曲力的影响较大,而桥墩纵向刚度对钢轨挠曲力的影响较小,为城市轨道交通设计提供理论参考依据.%Two types of urban rail transit double-track bridges are considered including the new type U-beam bridge and the traditional type box-girder bridge. The additional flexural forces and displacement distribution in CWR on the bridges have been calculated by finite element method. This paper carried out a detailed analysis on the flexural forces in tracks, the pier forces and bridge deflections owing to the changes in the longitudinal resistance, bridge spans and pier stiffness. Results showed that longitudinal resistance, bridge spans affect the rail additional flexural forces to a larger extent and the pier stiffness less affects the rail additional flexural forces. These results can provide a theoretical basis for the design of urban rail transit bridges.

  10. 高速铁路桥梁移动模架结构计算及预拱度设置%Calculation of Movable Die Carrier and Determination of Pre-camber of Bridge of High-speed Railway

    Institute of Scientific and Technical Information of China (English)

    吴尚德

    2013-01-01

    Research purposes: The bridges in the special sections of the Shenyang - Dandong Passenger Dedicated Line needed to be built by using the bridging machine with movable die carrier because of the natural environment conditions. The calculation was made to verify the design and manufacturing qualities of the MZ900S type Bridging machine with upstriker movable die carrier, know the actual deflection and stiffness of the bridging machine under the various working states during construction of cast - in - situ box girder and determine the reasonable pre - camber according to the y = 0. 121 3x2 -30. 1 for the purpose of ensuring the bridging machine in the good working state in service. Research conclusions: (1) The calculation and heaped loading test showed the strength, stiffness, manufacturing quality and assembly quality of the movable die carrier met the design requirements and the pre - camber was reasonable according to the y = 0. 121 3x2 -30. 1. (2) The movable die carrier had the features of the clear loading on the structure, good adaptability, perfect functions and high mechanization. (3) The movable die carrier met the construction requirements for the 24 m box girder, the curve bridge, the bidirectional 32 m box girder with assembly of integrated 32 m bridge opening.%研究目的:根据沈丹客运专线沿线桥梁桥址所处自然环境条件,对于部分特殊地段桥梁,需采用移动模架造桥机施工.本研究旨在通过实际计算验证MZ900S型上行式移动模架造桥机设计和制造质量,同时准确掌握现浇箱梁施工过程中模架造桥机各工况下的实际挠度和刚度,以确保设备在投入使用后能正常工作.研究结论:(1)计算及堆载试验表明移动模架强度、刚度、加工质量和拼装质量满足设计要求,按y=0.121 3x2-30.1设置预拱度是合理性的;(2)具有结构受力明确,适应能力强,功能完备,机械化程度高等优点;(3)可满足24 m箱梁、曲线桥梁、双向、32

  11. 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.

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

    International Nuclear Information System (INIS)

    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

  13. Comprehensive Real-Time Bridge Health Monitoring System of Tongtai Bridge

    Directory of Open Access Journals (Sweden)

    Lei Su-su

    2015-01-01

    Full Text Available Tongtai Bridge is the world’s largest suspension curve-girder-skew-arch bridge, which is located in Zhangjiakou, China. The understanding of mechanics characteristics is limited to such complex bridges, so it is necessary to establish reliable health monitoring system to investigate the static and dynamic responses and monitor the safety of the bridge. A comprehensive real-time bridge health monitoring system is establish, which includes four aspects: sensor system, data acquisition and transmission system, data processing and control system, structure early warning and security assessment system. The paper systematically describes the system design principles, sensor layout, and monitoring content, then expounds system integration and function of each subsystem.

  14. Verification of Flexural Behavior and Simplified Modeling of Steel-Concrete Composite Bridge

    Directory of Open Access Journals (Sweden)

    Odrobinak Jaroslav

    2014-06-01

    Full Text Available An experimental verification of actual flexural behavior of composite steel-concrete girder bridge is presented. The comparison of the experimentally obtained values with the values calculated using suitable computational model is also given in the paper. Introduction of changes in stiffness of concrete slab due to concrete cracking into the global analysis is discussed, too.

  15. Ultrasonic Underside Inspection for Fatigue Cracks in the Deck Plate of a Steel Orthotropic Bridge Deck

    NARCIS (Netherlands)

    Bakker, M.C.M.; De Jong, F.B.P.

    2003-01-01

    Due to an unexpected increase of heavy traffic large fatigue cracks appeared through the deck plate of orthotropic steel bridge decks in the Netherlands. Visual inspection revealed that this particular type of crack initiates where a weld joins the deck plate, a rib and a girder. These critical poin

  16. 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

    (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 and as there is no...... occurrence of severe slamming in the cases considered, the inexpensive non-linear strip theory is as accurate as the direct CFD calculation method. In a comparison with the results using the rigid body assumption, the increase in the vertical bending moment (VBM) amidships due to the flexibility of the hull...

  17. Application of Improved Hierarchic Genetic Algorithm to Damage Detection of the Main Girder for Cable-stayed Bridge%改进分层遗传算法在斜拉桥主梁损伤识别中的应用

    Institute of Scientific and Technical Information of China (English)

    李延强; 张阳

    2014-01-01

    标准遗传算法在解决像斜拉桥这类复杂结构的损伤识别问题时会出现提前收敛,即所谓“早熟”的现象。为了避免此现象的发生,提高损伤识别的效率与精度,提出一种基于改进分层遗传算法的斜拉桥主梁损伤识别方法。采用索力变化作为优化目标函数,将3种具有不同遗传算子的标准遗传算法与变量微调和灾变策略相结合,形成了一种具有灾变特性的分层遗传算法,以实验室独塔斜拉桥模型作为研究对象进行了数值仿真,结果表明:改进的分层遗传算法成功的避免了标准遗传算法“早熟”现象的发生,能快速有效的完成斜拉桥主梁各种损伤的识别;同时对此方法进行抗噪性分析发现,该方法具有良好的抗噪能力。%In the process of damage identification for high‐order nonlinear structure such as cable‐stayed bridges by the standard genetic algorithm ,premature convergence would appear .In order to avoid this ,an improved hierarchic genetic algorithm was proposed . The cable force change was used to establish the optimization function and threetypes of standard genetic algorithm were combined with variable fine‐tuning and hierarchic strategy .To establish a hierarchical genetic algorithm with catastrophe characteristics A single‐tower cable‐stayed bridge model was used in the numerical simulation and the result showed that the probability of premature convergence was reduced in the improved hierarchic genetic algorithm and and the cable‐stayed bridge damage was identified effectively .The anti‐noise performance was better .

  18. 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.

  19. Large scale testing of nitinol shape memory alloy devices for retrofitting of bridges

    International Nuclear Information System (INIS)

    A large scale testing program was conducted to determine the effects of shape memory alloy (SMA) restrainer cables on the seismic performance of in-span hinges of a representative multiple-frame concrete box girder bridge subjected to earthquake excitations. Another objective of the study was to compare the performance of SMA restrainers to that of traditional steel restrainers as restraining devices for reducing hinge displacement and the likelihood of collapse during earthquakes. The results of the tests show that SMA restrainers performed very well as restraining devices. The forces in the SMA and steel restrainers were comparable. However, the SMA restrainer cables had minimal residual strain after repeated loading and exhibited the ability to undergo many cycles with little strength and stiffness degradation. In addition, the hysteretic damping that was observed in the larger ground accelerations demonstrated the ability of the materials to dissipate energy. An analytical study was conducted to assess the anticipated seismic response of the test setup and evaluate the accuracy of the analytical model. The results of the analytical simulation illustrate that the analytical model was able to match the responses from the experimental tests, including peak stresses, strains, forces, and hinge openings

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

    DEFF Research Database (Denmark)

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

    The meshless and remeshed Discrete Vortex Method (DVM) has been widely used in academia and by the industry to model two-dimensional flow around bluff bodies. The implementation “DVMFLOW” [1] is used by the bridge design company COWI to determine and visualise the flow field around bridge sections, ...... solution for the admittance of a turbulent flow past a flat plate [4] and two types of bridge girder sections. A fair agreement is observed for sufficiently low turbulence intensities and sufficient spatial and temporal resolutions.......The meshless and remeshed Discrete Vortex Method (DVM) has been widely used in academia and by the industry to model two-dimensional flow around bluff bodies. The implementation “DVMFLOW” [1] is used by the bridge design company COWI to determine and visualise the flow field around bridge sections......, 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...

  1. Experimental Analysis of Stiffness of the Riveted Steel Railway Bridge Deck Members' Joints

    Science.gov (United States)

    Gocál, Jozef; Hlinka, Richard; Jošt, Jozef; Bahleda, František

    2014-12-01

    The paper deals with the real behaviour of the riveted steel railway bridge deck members' connections with respect to their bending stiffness. Attention is paid to the stringer-to-cross beam connection as well as the cross beam-to-main girder connection. The stiffness of the two connections is investigated on the basis of evaluation of the experimentally determined stress response of the observed structural members to the actual traffic load on an existing railway bridge.

  2. Experimental Analysis of Stiffness of the Riveted Steel Railway Bridge Deck Members’ Joints

    Directory of Open Access Journals (Sweden)

    Gocál Jozef

    2014-12-01

    Full Text Available The paper deals with the real behaviour of the riveted steel railway bridge deck members’ connections with respect to their bending stiffness. Attention is paid to the stringer-to-cross beam connection as well as the cross beam-to-main girder connection. The stiffness of the two connections is investigated on the basis of evaluation of the experimentally determined stress response of the observed structural members to the actual traffic load on an existing railway bridge.

  3. Performance in Transverse Direction of Fiber‐Reinforced Polymer Bridge Decks

    OpenAIRE

    Brühwiler, Eugen; Yanes Armas, Sonia; de Castro San Roman, Julia; Keller, Thomas

    2015-01-01

    Pultruded glass fiber‐reinforced polymer (GFRP) bridge decks distribute punctual vehicular loads to the underlying superstructure and can also act as the upper chord of hybrid main girders. The deck’s structural performance in both cases is influenced by its transverse behavior. The static bending behavior in the transverse‐to‐pultrusion direction of two GFRP bridge deck systems with trapezoidal (DS) and triangular (AS) cell cross‐sectional geometry was experimentally studied. Different load ...

  4. 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.

  5. 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.

  6. Redistribution of internal forces in composite concrete girders made continuous vs. time

    Directory of Open Access Journals (Sweden)

    Mašović Snežana

    2011-01-01

    Full Text Available Research on the long-term behavior of composite concrete girders made continuous is presented in the paper. Concrete precast element is cracked under construction load. Creep and differential shrinkage of precast and in-situ cast part of the girder also induce stresses in a structure. The subject of this investigation is redistribution of section forces in course of time for concrete girders subjected to change of the structural system. The aim of investigation is to verify design models and analytical procedures by experimental research.

  7. 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.

  8. Einstein's Boxes

    OpenAIRE

    Norsen, Travis

    2004-01-01

    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 exist...

  9. Application of Composite Structures in Bridge Engineering. Problems of Construction Process and Strength Analysis

    Science.gov (United States)

    Flaga, Kazimierz; Furtak, Kazimierz

    2015-03-01

    Steel-concrete composite structures have been used in bridge engineering from decades. This is due to rational utilisation of the strength properties of the two materials. At the same time, the reinforced concrete (or prestressed) deck slab is more favourable than the orthotropic steel plate used in steel bridges (higher mass, better vibration damping, longer life). The most commonly found in practice are composite girder bridges, particularly in highway bridges of small and medium spans, but the spans may reach over 200 m. In larger spans steel truss girders are applied. Bridge composite structures are also employed in cable-stayed bridge decks of the main girder spans of the order of 600, 800 m. The aim of the article is to present the cionstruction process and strength analysis problems concerning of this type of structures. Much attention is paid to the design and calculation of the shear connectors characteristic for the discussed objects. The authors focused mainly on the issues of single composite structures. The effect of assembly states on the stresses and strains in composite members are highlighted. A separate part of problems is devoted to the influence of rheological factors, i.e. concrete shrinkage and creep, as well as thermal factors on the stresses and strains and redistribution of internal forces.

  10. 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.

  11. 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......-scale onboard acceleration and stress measurements can be used to calculate sea state parameters. These calculated environmental data are verified by a comparison to hindcast data.In the third part of the paper the full-scale fatigue stress ranges are compared to results from an analytical design oriented...... calculation procedure for flexible ship hulls in short-term estimated sea states.Altogether, it is conceptually shown that by a combination of the onboard estimated sea state parameters with the described analytical fatigue damage prediction procedure a method can be established for real-time onboard decision...

  12. An influence of technological contraflexure of crane bridges on its durability

    Directory of Open Access Journals (Sweden)

    Artur BLUM

    2010-01-01

    Full Text Available Standard requirements till 1996 year during bridge crane manufacturing demanded a positive technological contraflexure. As a result of this process were implemented technological compressive stress into tensile zone from inertial and operational loads and tensile stress into compressive zone. This way there were redistributed resultant stress which have increased fatigue strength of exploited crane bridges. Actually valid standard PN-ISO 7363 has removed this obligatory requirement. Its use depends of crane buyer demands. Reduction of initial positive deflection can be seen after few years of crane operations. It is a case of girders permanent deflections increment. Article presents method of technological prestressing of bridge girders with its practical application to obtain positive contrafexure.

  13. Analysis of residual bearing capacity of cracked prestressed concrete continuous box bridges%预应力混凝土箱梁桥开裂后的残余承载力分析

    Institute of Scientific and Technical Information of China (English)

    王凌波; 赵煜

    2015-01-01

    为分析开裂预应力混凝土箱形桥梁结构开裂后的残余承载力,以裂缝统计特征参数为基础,用单元退化方式模拟正裂缝,用裂缝间的单向受压杆模拟裂缝间的承压效应,采用空间梁单元和三维杆单元分别模拟梁和预应力筋,以单元降温的方式模拟预加力的效应,形成空间刚架模型模拟斜裂缝。基于开裂后混凝土及预应力钢筋的基本假定,建立开裂后结构的计算方法。按照相似高度、开裂区域截面折减、折减自重补偿的原则将相似裂缝进行合并处理,得到裂缝区域的阶梯型折减刚度模型,提出承载能力折减系数计算方法以体现开裂后结构刚度的变化。经实桥算例验证,本文方法可正确判断静定及超静定预应力混凝土结构开裂后承载力的变化程度。%Based on the crack statistic characteristic parameters,the unit degradation mode was utilized to simu-late the fracture of prestressed concrete box bridges and analyze its residual bearing capacity.In the meantime, unidirectional compressive rod,space beam element and cooling unit form were adopted to simulate the effects of pressure among cracks,prestressed tendons and the pre -tension effect,in order to form a space rigid frame model.Based on some basic assumptions of cracked concrete and prestressed steel,the calculation method was established after cracking.Merging similar cracks by the principle of similar height,reduction of cracking area and reduction gravity compensation,the ladder -type stiffness degradation model of crack area was then estab-lished and a capacity reduction calculation method was proposed to reflect the change of the crack stiffness.The real bridge example proves that the method can correctly judge the change of bearing capacity for cracked static determinacy and indeterminacy concrete structures.

  14. Use of UHPC in Bridge Structures: Material Modeling and Design

    Directory of Open Access Journals (Sweden)

    Oguz Gunes

    2012-01-01

    Full Text Available Ultra-high-performance concrete (UHPC is a promising new class of concrete material that is likely to make a significant contribution to addressing the challenges associated with the load capacity, durability, sustainability, economy, and environmental impact of concrete bridge infrastructures. This paper focuses on the material modeling of UHPC and design of bridge girders made of UHPC. A two-phase model used for modeling the behavior of UHPC was briefly discussed, and the model was implemented in a preliminary design case study. Based on the implemented design and the reported use of UHPC in bridge applications, the advantages, limitations, and future prospects of UHPC bridges were discussed, highlighting the need for innovative research and design to make optimum use of the favorable properties of the material in bridge structures.

  15. 沉湖汉江特大桥主桥连续刚构施工技术%Construction Techniques for Continuous Rigid Frame of Main Bridge of Chenhu Hanjiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    赵天元

    2012-01-01

    The main bridge of Chenhu Hanjiang River Bridge is a continuous rigid frame bridge with span arrangement (102 + 168 + 102) m. The superstructure of the bridge is the single-cell single-box girder with variable depth and variable section and the substructure has round en-ded thin-wall twin piers supported on bored pile foundations. The holes of the bored piles for the main bridge were bored by the rotary boring machines and the pile caps were constructed in the steel sheet pile cofferdams. The segments No. 0 of the superstructure were constructed on the scaffolding while the rest of the segments were cantileveredly cast in situ by the diamond-shape form travelers. At the closure gap at the central span, the 4 000 kN horizontal pushing force was applied to fulfill the closure of the span. To ensure the construction quality and safety and to keep the actual status of the bridge to approach the design status to the maximum extent, the closure precision of the closure gap was made to accord with the requirements in the codes and the geometric shape of the completed bridge was made to meet the design status through the construction monitoring and control.%沉湖汉江特大桥主桥为(102+168+102)m连续刚构桥,上部结构为单箱单室、变高度、变截面梁,下部结构采用双墩薄壁圆端形桥墩、钻孔灌注桩基础.主桥桩基采用旋转钻机成孔,承台采用钢板桩围堰法施工;上部结构0号块采用落地式支架法施工,其余节段采用菱形挂篮悬臂浇筑施工,在中跨合龙口设置4 000 kN的水平顶推力,完成中跨合龙.为了保证施工质量及安全,使该桥的实际状态最大限度地趋近设计状态,通过施工监控,使中跨合龙口精度满足规范要求、成桥线形与设计吻合.

  16. Automatic construction management of inclined cable in Heira bridge; Heirahashi ni okeru syazai keburu seko kanri no jidoka

    Energy Technology Data Exchange (ETDEWEB)

    Kajiyama, K.

    1996-03-01

    First one sided PC inclined cable bridge based on precast block additional method is constructed at Heira in Japan. Measurements of main girder deflection and main tower displacement values are considered as necessary factors in construction of inclined cable bridge. Efficient and rapid tension force supervision of inclined cable in every stage of construction is required for the above mentioned purpose. Automatic management of tension of inclined cable in Heira bridge construction is considered in this investigation. Construction of measuring system, installation, tension force adjustment and its decision management process, required special characteristics of tension, calculation sheet`s process et., are explained. Following observations are noted when precast method is compared with cast in place method for Heira bridge. Construction cycle of main girder is small and cycle until end of tension for 1 block construction to last block construction is equal to 1.6/day/block. 12 figs., 1 tab.

  17. Bridge? What's a Bridge?

    Science.gov (United States)

    Gutsche, George

    1996-01-01

    Considers the metaphor of the "bridge" as it applies to Russian-language courses at the university level. The article examines broader curricular issues of technology, innovation, and outside pressures on language teaching. (22 references) (CK)

  18. Seismic response analysis of high-speed vehicle-bridge considering soil-structure interaction%考虑桩-土作用的高速列车-桥梁地震响应分析

    Institute of Scientific and Technical Information of China (English)

    陈令坤; 蒋丽忠; 陶磊; 余志武

    2012-01-01

    Based on the finite beam element method, two kinds of whole bridge models of high-speed railway multi-span simply-supported bridge are set up. One is vehicle-bridge model including pile foundation, the dynamic impedances of the layered soil are presented, the improved Penzien model is used to simulate the soil-structure interaction (SSI); the other is vehicle-bridge model where pier bottom is consolidated without considering SSI; the seismic responses of the models are computed at different vehicle speeds, pier heights, earthquake strengths and earthquake waves. The calculation results show that the influence of the SSI on seismic responses of high-speed vehicle-bridge on soft foundation can not be ignored; the lateral displacement and acceleration of the bridge are influenced by low-frequency components, those low-frequency components interact with the earthquake wave incident from bottom side of the piles, which change the spectrum composition of the foundation movement, the frequency components which approach to bridge vibration frequency are strengthened; the lateral displacement and acceleration of bridge increase a lot after considering SSI; the vertical vibration frequency of the bridge changes little while considering SSI; the vertical displacement of the boxing girder increases little with the increase of pier height and vehicle speed; the high-frequency components which are caused mainly by the vehicle load and the track irregularity significantly influenced on the vertical acceleration of the boxing girder.%基于空间梁单元有限元法,建立了两种高速铁路多跨简支梁桥的全桥空间分析模型,一种是包括桩基的列车-桥梁模型,给出成层土的动力阻抗,采用改进的Penzien模型模拟桩-土作用;一种是不考虑桩-土作用的墩底固结的列车-桥梁模型;分析了两种模型的自振特性,计算了两种模型在不同车速、墩高、地震强度、不同地震波等工况下的地震反应.计算

  19. 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...

  20. A user-friendly design method for the webs of economic-fabrication steel bridge girders

    Czech Academy of Sciences Publication Activity Database

    Škaloud, Miroslav; Zörnerová, Marie

    Brusel : ECCS European Convention for Constructional Steelwork, 2008 - (Ofner, R.; Beg, D.; Fink, J.; Greiner, R.; Unterweger, H.), s. 893-898 ISBN 92-0147-000-90. [Eurosteel 2008. Graz (AT), 03.09.2008-05.09.2008] R&D Projects: GA ČR(CZ) GA103/06/0064; GA AV ČR(CZ) IAA200710603 Grant ostatní: GA ČR(CZ) GA103/08/0275 Institutional research plan: CEZ:AV0Z20710524 Keywords : thin-walled construction * post-buckled behaviour * repeated loading Subject RIV: JM - Building Engineering

  1. The fatigue behaviour of the breathing webs of steel bridge girders

    Czech Academy of Sciences Publication Activity Database

    Škaloud, Miroslav; Zörnerová, Marie

    2005-01-01

    Roč. 11, č. 4 (2005), s. 323-336. ISSN 1392-3730 R&D Projects: GA ČR(CZ) GA103/05/2059 Institutional research plan: CEZ:AV0Z20710524 Keywords : repeated loads * fatigue crack * S-N curves Subject RIV: JM - Building Engineering

  2. 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.

  3. Random vibration analysis of train-bridge under track irregularities and traveling seismic waves using train-slab track-bridge interaction model

    Science.gov (United States)

    Zeng, Zhi-Ping; Zhao, Yan-Gang; Xu, Wen-Tao; Yu, Zhi-Wu; Chen, Ling-Kun; Lou, Ping

    2015-04-01

    The frequent use of bridges in high-speed railway lines greatly increases the probability that trains are running on bridges when earthquakes occur. This paper investigates the random vibrations of a high-speed train traversing a slab track on a continuous girder bridge subjected to track irregularities and traveling seismic waves by the pseudo-excitation method (PEM). To derive the equations of motion of the train-slab track-bridge interaction system, the multibody dynamics and finite element method models are used for the train and the track and bridge, respectively. By assuming track irregularities to be fully coherent random excitations with time lags between different wheels and seismic accelerations to be uniformly modulated, non-stationary random excitations with time lags between different foundations, the random load vectors of the equations of motion are transformed into a series of deterministic pseudo-excitations based on PEM and the wheel-rail contact relationship. A computer code is developed to obtain the time-dependent random responses of the entire system. As a case study, the random vibration characteristics of an ICE-3 high-speed train traversing a seven-span continuous girder bridge simultaneously excited by track irregularities and traveling seismic waves are analyzed. The influence of train speed and seismic wave propagation velocity on the random vibration characteristics of the bridge and train are discussed.

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

    DEFF Research Database (Denmark)

    Rasmussen, Johannes Tophøj; Hejlesen, Mads Mølholm; Larsen, Allan; Walther, Jens Honore

    The meshless and remeshed Discrete Vortex Method (DVM) has been widely used in academia and by the industry to model two-dimensional flow around bluff bodies. The implementation “DVMFLOW” [1] is used by the bridge design company COWI to determine and visualise the flow field around bridge sections......, 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...

  5. 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

  6. 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 ...

  7. 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...

  8. 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.

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

    International Nuclear Information System (INIS)

    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

  10. Sensitivity and statistical analysis within the elaboration of steel plated girder resistance

    Czech Academy of Sciences Publication Activity Database

    Melcher, J.; Škaloud, Miroslav; Kala, Z.; Karmazínová, M.

    2009-01-01

    Roč. 5, č. 2 (2009), s. 120-126. ISSN 1816-112X. [International conf. on steel and aluminium structures /6./. Oxford, 24.06.2007-27.06.2007] Institutional research plan: CEZ:AV0Z20710524 Keywords : steel structures * fatigue * sensitivity * imperfection * plated girder Subject RIV: JM - Building Engineering

  11. 流冰撞击力作用下列车-简支梁桥耦合振动分析%Coupled vibration analysis for train and simply-supported bridge system subjected to floating-ice collision

    Institute of Scientific and Technical Information of China (English)

    夏超逸; 雷俊卿; 张楠

    2012-01-01

    A coupled vibration analysis model was established for train-bridge system subjected to floating-ice collision load. The force originated from the floating-ice collision, whose time history was measured in site experiment was taken as the load applied on the bridge piers in transient style. The dynamic responses of railway bridges subjected to floating-ice collision and their influences on the running safety of high-speed trains were analyzed by numerical simulation. The time history of a train traveling on a seven梥pan simply-supported bridge with 24m box girders when the floating-ice strikes bridge piers was simulated and the dynamic responses of the bridge and train vehicles were investigated. The calculation results show that the lateral acceleration of the bridge and running safety indices such as the derailment factors and offload factors of train vehicles will exceed the corresponding allowances when the train speed is higher than 250 km/h, indicating that collision of floating-ice has obvious effect on coupled vibration responses of train-bridge system.%建立撞击荷载作用下列车-桥梁系统动力分析模型,将现场实测的流冰撞击力时程作为系统的撞击荷载.通过计算机仿真分析,对流冰撞击作用下高速铁路桥梁的动力响应及其对桥上列车运行安全的影响进行研究.采用自编程序模拟列车过桥的全过程,计算分析7m×24 m简支箱梁桥在流冰撞击力作用下动力响应及桥上高速列车的动力响应.计算结果表明,在实测流冰撞击力作用下,桥梁横向加速度以及车辆脱轨系数和轮重减载率等行车安全指标在列车速度250 km/h以上时超过容许值,说明流冰撞击作用对车桥系统耦合振动响应具有较大的影响.

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

    Directory of Open Access Journals (Sweden)

    A. Klimpel

    2007-09-01

    Full Text Available 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 sources of the concrete damage due to high welding temperature and stresses.Findings: It was shown that MMA welding at vertical-up position, by a rutile coated electrode of diameter 3,2 [mm], at welding current 110-120 [A], of the butt welds of tee-joints of girders and the insert plate does not cause any harmful and damaging effect to concrete, which temperature in a region of the contact with the bottom surface of the insert plate does not exceed 240 [˚C] during full cycle of welding. Tensile and compression stresses of concrete are transmitted mainly by anchoring bars, fixed in concrete and also by reinforcing fabric of concrete, and do not cause any cracks of concrete.Research limitations/implications: To achieve more consistent results of the numerical analysis of stresses and deformation distribution in the insert plate with experimental results, it is necessary to calculate plastic deformation of materials and also take into consideration nonlinear change of yield point (plasticity as a function of temperature.Practical implications: The technology was applied for welding of the girders to insert plates of the telecommunication tower in Kuwait.Originality/value: Welding procedure specification ensuring high quality of the welded joints of girders and insert plate of composite steel-concrete structure.

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

    Directory of Open Access Journals (Sweden)

    A. Lisiecki

    2007-07-01

    Full Text Available 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 concrete damage due to high welding temperature and stresses.Findings: It was shown that MMA welding at vertical-up position, by a rutile coated electrode of diameter 3,2 [mm], at welding current 110-120 [A], of the butt welds of tee-joints of girders and the insert plate does not cause any harmful and damaging effect to concrete, which temperature in a region of the contact with the bottom surface of the insert plate does not exceed 240 [°C] during full cycle of welding. Tensile and compression stresses of concrete are transmitted mainly by anchoring bars, fixed in concrete and also by reinforcing fabric of concrete, and do not cause any cracks of concrete.Research limitations/implications: To achieve more consistent results of the numerical analysis of stresses and deformation distribution in the insert plate with experimental results, it is necessary to calculate plastic deformation of materials and also take into consideration nonlinear change of yield point (plasticity as a function of temperature.Practical implications: The technology was applied for welding of the girders to insert plates of the telecommunication tower in Kuwait.Originality/value: Welding procedure specification ensuring high quality of the welded joints of girders and insert plate of composite steel-concrete structure.

  14. 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...

  15. Laryngeal (Voice Box) Cancer

    Science.gov (United States)

    ... Meeting Calendar 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 ...

  16. 多箱渡槽槽身静风三分力系数风洞试验研究%A wind tunnel test study on aerostatic coefficients of large scale multi-box aqueduct bridge deck

    Institute of Scientific and Technical Information of China (English)

    李遇春; 邸庆霜; 张文杰; 张婷婷

    2012-01-01

    A wind tunnel test for the six scaled multi-box aqueduct decks (including 3 two-box and 3 three-box models) was conducted. The cases with full and without water, and with different wind attack an- gles are considered respectively. The drag, lift and pitching moment coefficients of multi-box aqueduct decks were obtained by the test result analyses. The surface pressure distributions and the aerostatic coeffi- cients of the test models were displayed and discussed. The results show that: (1) The wind flow field around multi-box aqueduct deck is similar to that of blunt body; (2) The drag force is the most important wind load among the three static loads; (3) The drag coefficient decreases with the increasing of width/ height ratio of aqueduct decks in the whole tendency.%对6个多箱式渡槽槽身刚性测压模型进行了风洞试验研究,分别模拟了满槽、空槽以及不同风攻角的试验工况。根据试验结果得到了槽身模型的静风三分力(阻力、升力和扭矩)系数,讨论了模型风压分布以及三分力系数的变化规律。试验结果表明:(1)多箱式渡槽槽身绕流更趋近于钝体绕流;(2)槽身风荷载主要表现为风阻力;(3)阻力系数在总体趋势上随着槽截面宽高比的增加而减小。试验结果可为多箱渡槽的抗风研究与设计提供初步的参考。

  17. Structure-borne noise of railway composite bridge: Numerical simulation and experimental validation

    Science.gov (United States)

    Li, Xiaozhen; Liu, Quanmin; Pei, Shiling; Song, Lizhong; Zhang, Xun

    2015-09-01

    In order to investigate the characteristics of the noise from steel-concrete composite bridges under high-speed train loading, a model used to predict the bridge-borne noise is established and validated through a field experiment. The numerical model for noise prediction is developed based on the combination of spatial train-track-bridge coupled vibration theory and Statistical Energy Analysis (SEA). Firstly, train-track-bridge coupled vibration is adopted to obtain the velocity time history of the bridge deck vibration. Then, the velocity time history is transferred into frequency domain through FFT to serve as the vibratory energy of SEA deck subsystems. Finally, the transmission of the vibratory energy is obtained by solving the energy balance equations of SEA, and the sound radiation is computed using the vibro-acoustic theory. The numerically computed noise level is verified by a field measurement. It is determined that the dominant frequency of steel-concrete composite bridge-borne noise is 20-1000 Hz. The noise from the bottom flange of steel longitudinal girder is less than other components in the whole frequency bands, while the noise from web of steel longitudinal girder is dominant in high frequency range above 315 Hz. The noise from concrete deck dominates in low-frequency domain ranges from 80 Hz to 160 Hz.

  18. 淦河桥梁方案设计研究%Design and Research on Bridge Scheme of Gan River

    Institute of Scientific and Technical Information of China (English)

    蔡忠华

    2016-01-01

    Following the principal of applicable,economical,safe and beautiful and taking the bridge crossing Gan River in Jingui west road in Xianning City as the engineering background,four types of bridge design schemes are introduced,namely simple supported girder bridge,continuous girder bridge,through tied-arch bridge,and cable-stayed bridge without backstays.The tied arch bridge is chosen as the recommended proposal by taking bridge design,landscape feature,construction feasibil-ity and economy into comprehensive consideration.%遵循“适用、经济、安全、美观”的桥梁设计基本原则,以咸宁市金桂西路跨淦河大桥为工程背景,提供了4种桥梁设计方案:无背索斜拉桥,预应力混凝土连续梁桥、预应力混凝土简支 T梁桥、下承式系杆拱桥。综合考虑论证桥梁构造设计、景观特色、施工可行性和经济性等因素,选取下承式系杆拱桥作为推荐方案。

  19. NUMERICAL ANALYSIS OF CRACK AND STRAIN BEHAVIOR OF RC SLAB IN STEEL-CONCRETE COMPOSITE GIRDER UNDER NEGATIVE BENDING

    Science.gov (United States)

    Sakaguchi, Junichi; Nakajima, Akinori; Suzuki, Yasuo

    The sophisticated numerical analysis method is required to simulate the strain behavior of the reinforcement and the crack width of the RC slab, although many researches are conducted on the cracking behavior of the RC slab in the composite girder under the negative bending. In this paper, the numerical analysis method is constructed to evaluate the strain behavior of the reinforcement and the crack width of the RC slab in the steel-concrete composite girder subjected to the negative bending. The analysis method using the rigid body spring model takes into account the imperfect composite action between the steel girder and the RC slab, the bond between the reinforcement and the concrete, and the shrinkage of the concrete. As a result, it is confirmed that the analysis method can simulate the crack and the strain behavior of RC slab quantitatively in the steel-concrete composite girder under the negative bending.

  20. 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

  1. Field Test of a Bridge Deck with Glass Fiber Reinforced Polymer Bars as the Top Mat of Reinforcement

    OpenAIRE

    Harlan, Matthew

    2004-01-01

    The primary objective of this research project was to perform live load tests on a bridge deck with GFRP reinforcement in the field under service conditions. The strains and deflections in the span reinforced with GFRP in the top mat were recorded under a series of truck crossings, and these were compared to the span reinforced with all steel bars under identical loading conditions, as well as design values and other test results. Transverse strains in the GFRP bars, girder distribution fac...

  2. Scaled down model design of shaking table test of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Yan Jukao; Han Lei; Zhao Yi; Peng Tianbo

    2012-01-01

    Taizhou Bridge is the first kilometer level three-pylon two-span suspension bridge in the world and the structural complexity has significant effects on the seismic performance of the bridge. Shaking table test of Taizhou Bridge is arranged to investigate the effects of non-uniform ground motion input, collision between main and side spans and optimal seismic structural system. It' s very important and difficult to design and manufacture the scaled down model of Taizhou Bridge used during the shaking table test. The key point is that the girder and pylons are very hard to be manufactured if the similarity ratio is strictly followed. Based on the finite element method (FEM) analysis, a simplified scaled down model is designed and the bending stiffness of the girder and pylon are strictly simulated, and the torsion stiffness and axial stiffness are not strictly simulated. The inner forces and displacements of critical sections, points of simplified model and theoretical model are compared by FEM analysis, and it' s found out that the difference between the seismic responses is relatively small. So, the simplified model can be used to conduct the shaking table test by the FEM verification.

  3. Myocardial Bridging.

    Science.gov (United States)

    Yuan, Shi-Min

    2016-02-01

    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. PMID:27074276

  4. 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.

  5. Flexible concrete link slabs used as expansion joints in bridge decks

    DEFF Research Database (Denmark)

    Lárusson, Lárus Helgi; Fischer, Gregor

    2011-01-01

    water through the expansion joint and subsequent corrosion of girders and girder bearings. Investigations on joint-less superstructures using conventional steel reinforcement in so-called concrete link slabs indicate improved performance and economic feasibility. However, this concept requires...... relatively large amounts of steel reinforcement for crack control purposes and consequently provides a relatively large flexural stiffness and negative moment capacity at the joint between the spans. These contradicting requirements and effects in existing replacement concepts for damaged mechanical bridge...... joints are currently unresolved. In the proposed system described in this paper, a ductile cement-based composite section reinforced with Glass Fiber Reinforced Polymers (GFRP) replaces the damaged expansion joint. The combination of this ductile concrete together with corrosion resistant GFRP...

  6. Interactive Shear Buckling Of Plate Girder with Corrugated Web (Analytical Solution)

    OpenAIRE

    Prof.Dr:S.A.Tohamy; Ass.Prof.Dr:A.B.Saddek; Eng: Asmaa.Y.Hamed

    2016-01-01

    This paper presents analytical studies the elastic interactive shear buckling stress of corrugated steel web is calculated by all possible failure criteria (steel yielding, local and global buckling stresses), using Minimum Potential Energy Method to determine critical shear stress of local and global buckling of plate girder with corrugated webs. The results are compared with Finite element method (FEM) using ANSYS/V12. It found that the proposed equations are a good agreement with the resul...

  7. Statistical and sensitivity analysis within the elaboration of steel plated girders

    Czech Academy of Sciences Publication Activity Database

    Melcher, J.; Škaloud, Miroslav; Kala, Z.; Karmazínová, M.

    Oxford : Oxford Brookes University, 2007 - (Beale, R.), s. 309-315 ISBN 978-0-9556254-0-4. [Steel and aluminium structures ICSAS´07 /6./. Oxford (GB), 24.07.2007-27.07.2007] Grant ostatní: GA ČR(CZ) GA103/05/2059; GA ČR(CZ) GA103/07/1067 Institutional research plan: CEZ:AV0Z20710524 Keywords : steel plate girders * initial imperfection * web breathing Subject RIV: JM - Building Engineering

  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. 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...

  10. 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.

  11. Design of Main Pier Foundations for Guyumen Channel Bridge of Pingtan Strait Rail-cum-Road Bridge%平潭海峡公铁两用大桥鼓屿门航道桥主墩基础设计

    Institute of Scientific and Technical Information of China (English)

    孙英杰; 梅新咏

    2016-01-01

    平潭海峡公铁两用大桥鼓屿门航道桥采用主跨364 m的钢桁混合梁斜拉桥方案,桥址区水深流急、风大涌险、潮大浪高、地质复杂、冲刷严重、航道等级高、有效作业时间短。为适应该桥桥址气象、水文、地质等条件,考虑通航安全、技术可行及工程经济性等要求,确定采用高桩承台方案,并对φ3.0m、φ4.0m、φ4.5m钻孔桩基础方案进行比选,确定选用φ4.5m钻孔桩基础方案,按先平台后吊箱围堰的顺序施工。大直径桩基础中各桩采用单独配筋设计;防撞结构由吊箱围堰、V形防撞梁及联结系组成,采用可拆卸式设计,并在围堰外壁设置消波孔;钻孔桩采用KTY5000型动力头钻机,并配制PESF935型中压空压机循环排渣,利用泥浆护壁、锲齿或球齿滚刀钻头钻具切削岩面成孔;采用内径406 mm的单导管法施工水下C45混凝土。%The Guyumen Channel Bridge of the Pingtan Strait Rail‐cum‐Road Bridge adopts the scheme of a steel truss hybrid girder cable‐stayed bridge with a main span of 364 m .The construc‐tion of the bridge is constrained by the complex geological and hydrological conditions at the bridge site ,including deep water ,strong currents ,heavy winds ,hazardous torrents ,high tides and tur‐bulent waves ,severe scour ,high grade of navigational channel and tight efficient operation time . To suit the meteorological ,hydrological and geological conditions at the bridge site ,by considering the safety and technical feasibility and engineering economy ,it was determined that the elevated pile cap scheme be adopted .The pile foundations formed of bored piles respectively with 3 .0 m , 4 .0 m and 4 .5 m diameters were compared ,and the foundation scheme of 4 .5 m diameter bored piles was finally chosen .The foundation was constructed following the sequence of constructing the platform first and then the suspended box cofferdam .For the

  12. 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.

  13. Intelligente Bauwerke

    DEFF Research Database (Denmark)

    Schneider, Ronald; Fischer, Johannes; Straub, Daniel; Thöns, Sebastian; Bügler, Maximilian; Borrmann, André

    This report describes a system model for assessing and updating the condition state and reliability of bridge structures utilizing inspection and monitoring data. The system model was developed on the basis of an existing continuous single-cell prestressed concrete box girder. The system model...... aging box girder. The ultimate capacity of a box girder conditional on a certain system deterioration state is estimated on the basis of plastic hinge theory. System failure occurs if sufficient plastic hinges develop under the applied loads such that a kinematic collapse mechanism of the continuous box...... girder is formed. This approach accounts for structural redundancies of the continuous box girder with respect to its plastic cross-sectional capacity and its static indeterminacy. To prove the concept, a software prototype has been developed which couples an easy-to-use graphical user interface (front...

  14. 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...

  15. 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.

  16. 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.

  17. 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.

  18. Visualization of active crack on bridge in use by mechanoluminescent sensor

    Science.gov (United States)

    Terasaki, Nao; Xu, Chao-Nan; Li, Chenshu; Zhang, Lin; Li, Chengzhou; Ono, Daisuke; Tsubai, Masayoshi; Adachi, Yoshio; Imai, Yusuke; Ueno, Naohiro; Shinokawa, Toshio

    2012-04-01

    Innovative mechanoluminescent (ML) particles emit light repeatedly in response to small stresses applied, such as deformation, friction, or impact. When dispersedly coated on a structure, each particle acts as a sensitive mechanical sensor, while the 2-dimentional emission pattern of the whole assembly reflects well the dynamical stress distribution inside the structure and mechanical information around crack and defect. Thus, we have applied the remarkable strong points of ML sensing technique to a bridge in use as a real social structure for the first time. For the first ML monitoring test at bridge, we selected a relatively old bridge (established in 1954, 3-span continuous T-type RC bridge, length 24.4 m, width: 7.89 m). The ML sheet type sensors were put around the central area (700×400 mm) of the main girder, and ML images originated from dynamic load application via general traffic vehicles had recorded by using lab-made CCD camera under roughly dark condition. As the result, we successfully detected intense ML patterns not only along visible crack but also at round soundless part on the girder at a glance with responding ML intensity reflecting the crack mouth opening displacement (CMOD) of visible crack and invisible progressing microcrack.

  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. Programmevaluierung Bridge

    OpenAIRE

    Warta, Katharina; Good, Barbara; Geyer, Anton

    2009-01-01

    BRIDGE is an initiative funded by the Ministry for Transport, Innovation and Technology (BMVIT) that aims to close the “funding gap” between basic and applied research in stand-alone projects with the primary objective of jointly developing the potential of basic and applied research. BRIDGE acts as an  umbrella structure under which the Austrian Science Fund (FWF) and the  Austrian Research Promotion Agency (FFG) coordinate two thematically open funding programmes: The ...

  1. Analysis on Adhesively-Bonded Joints of FRP-steel Composite Bridge under Combined Loading: Arcan Test Study and Numerical Modeling

    OpenAIRE

    Xu Jiang; Xuhong Qiang; Henk Kolstein; Frans Bijlaard

    2016-01-01

    The research presented in this paper is an experimental study and numerical analysis on mechanical behavior of the adhesively-bonded joint between FRP sandwich bridge deck and steel girder. Generally, there are three typical stress states in the adhesively-bonded joint: shear stress, tensile stress, and combination of both. To realize these stress states in the adhesively-bonded joint during tests, a specific loading device is developed with the capacity of providing six different loading ang...

  2. The Maine Music Box

    OpenAIRE

    Lutz, Marilyn; Gallucci, Laura

    2005-01-01

    The paper describes the Maine Music Box and examines its potential as a tool for teaching and learning music. Pedagogical concepts are demonstrated using MIDI, Scorch, image and streaming video files.

  3. 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 ...

  4. 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,...

  5. Rotational Angle Measurement of Bridge Support Using Image Processing Techniques

    Directory of Open Access Journals (Sweden)

    Young-Soo Park

    2016-01-01

    Full Text Available Measuring a very small rotational angle accurately and dynamically is indeed a challenging issue, especially in the case of bridge support. Also, existing inclinometers do not have sufficient resolution and accuracy to measure a bridge’s rotational angle. In this study, a new measurement system was developed to provide a practical means for measuring dynamic rotational angle of a bridge support. It features high resolution and accuracy compared with the available systems on the market. By the combinational use of a laser pointer and a vision-based displacement measurement system, the measurement accuracy was significantly increased. The accuracy and applicability were investigated through laboratory tests. From the laboratory tests, it has been found that the developed system can be applicable to bridge support with very small rotational angle. The effectiveness of the developed system was verified through field tests on real bridges. From the full-scale implementation on two PSC girder bridges, it is observed that the proposed system can measure the rotational angle with a high accuracy and reliability.

  6. 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

  7. Some remarks in regard to the fatigue analysis of steel plate girders with breathing webs

    Czech Academy of Sciences Publication Activity Database

    Maquoi, R.; Škaloud, Miroslav

    Praha : České Vysoké Učení technické v Praze, 2003 - (Studnička, J.), s. 397-402 ISBN 80-01-02747-3. [Česko-slovenská konference s mezinárodní účastí - Ocelové konstrukce a mosty /20./. Praha (CZ), 17.09.2003-20.09.2003] R&D Projects: GA AV ČR IAA2071102 Institutional research plan: CEZ:AV0Z2071913 Keywords : steel plate girders * fatigue limit state * fatigue crack Subject RIV: JM - Building Engineering

  8. The effects of longitudinal prestressing on the box shear lag by the difference method%纵向预应力对箱梁剪力滞效应的差分解

    Institute of Scientific and Technical Information of China (English)

    刘扬; 王东东

    2013-01-01

    Guided by the energy variational principle and based on the different longitudinal displacements of three parabolas,the basic differential equation of the shear lag of cantilever box girders is obtained,and its feasibility is proved by using the finite difference method.The method is applied to analyze the shear lag effect of cantilever box girder under the longitudinal prestressing of equivalent loaf.Based on the ANSYS,a model which features that the box girder is built and simulated by Solid 95,and the prestressed steel is simulated by Link 10.Later,the model is used to analyze the coefficient distribution rule of the shear lag of the box girder under the longitudinal prestressing,and then this rule is compared with the result from finite difference method.This comparison proves the applicability of the difference method in the study of the shear lag effect of the box girder under longitudinal prestressing of equivalent loaf,and longitudinal prestressing's effects on the shear lag effect of beam is also analyzed.%选取3次抛物线变化的纵向位移,通过能量变分原理得到悬臂箱梁的剪力滞基本微分方程,再利用有限差分法进行求解,将该方法用于分析纵向预应力等效荷载作用下的悬臂箱梁剪力滞效应.运用ANSYS有限元软件建立模型,采用Solid 95单元模拟箱梁,采用Link8单元模拟预应力钢束,分析在纵向预应力作用下箱梁剪滞系数分布规律并与差分法求解的结果进行对比.经过对比,验证了差分法求解纵向预应力等效荷载作用下箱梁剪滞效应的可行性,同时分析了纵向预应力对箱梁剪滞效应的影响.

  9. 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...

  10. 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...

  11. Assessment on transient sound radiation of a vibrating steel bridge due to traffic loading

    Science.gov (United States)

    Zhang, He; Xie, Xu; Jiang, Jiqing; Yamashita, Mikio

    2015-02-01

    Structure-borne noise induced by vehicle-bridge coupling vibration is harmful to human health and living environment. Investigating the sound pressure level and the radiation mechanism of structure-borne noise is of great significance for the assessment of environmental noise pollution and noise control. In this paper, the transient noise induced by vehicle-bridge coupling vibration is investigated by employing the hybrid finite element method (FEM) and boundary element method (BEM). The effect of local vibration of the bridge deck is taken into account and the sound responses of the structure-borne noise in time domain is obtained. The precision of the proposed method is validated by comparing numerical results to the on-site measurements of a steel girder-plate bridge in service. It implies that the sound pressure level and its distribution in both time and frequency domains may be predicted by the hybrid approach of FEM-BEM with satisfactory accuracy. Numerical results indicate that the vibrating steel bridge radiates high-level noise because of its extreme flexibility and large surface area for sound radiation. The impact effects of the vehicle on the sound pressure when leaving the bridge are observed. The shape of the contour lines in the area around the bridge deck could be explained by the mode shapes of the bridge. The moving speed of the vehicle only affects the sound pressure components with frequencies lower than 10 Hz.

  12. 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.

  13. User - friendly design of the webs of economic fabrication steel bridge girders - one of the new results Prague breathing research

    Czech Academy of Sciences Publication Activity Database

    Škaloud, Miroslav; Zörnerová, Marie

    Brno : Akademické nakladatelství CERN, s.r.o., 2007, 2007 - (Melcher, J.; Karmazínová, M.), s. 455-460 ISBN 978-80-7204-543-3. [Experiment - významný zdroj poznání a verifikace metod navrhování nosných stavebních konstrukcí. Brno (CZ), 25.10.2007-26.10.2007] R&D Projects: GA AV ČR(CZ) IAA200710603; GA ČR(CZ) GA103/06/0064 Grant ostatní: GA ČR(CZ) GA103/05/2003; GA ČR(CZ) GA103/05/2059 Institutional research plan: CEZ:AV0Z20710524 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : repeated loads * web breathing * fatigue limit state Subject RIV: JM - Building Engineering

  14. 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.

  15. Teaching with Box Tops.

    Science.gov (United States)

    Raiser, Lynne; D'Zamko, Mary Elizabeth

    1984-01-01

    Using environmental materials (such as the phone book and placemats from fast food restaurants) can be a motivating way to teach learning disabled students skills and concepts, as shown in an approach to reading, math, science and nutrition, and social studies instruction using a JELL-O brand gelatin box. (CL)

  16. 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.

  17. Glove box posting system

    International Nuclear Information System (INIS)

    A system for posting objects into closed containers, such as glove boxes, is described in which the bag used, preferably made of plastic, does not have to be fitted and sealed by the operator during each posting operation. (U.K.)

  18. Cereal Box Totems.

    Science.gov (United States)

    Jones, AnnMarie

    2002-01-01

    Presents a multicultural project used with fourth-grade students in which they created a three-dimensional totem pole using leftover cereal boxes. Discusses in detail how to create the totem pole. Explains that students learned about Northwest American Indians in class. (CMK)

  19. PHOTOCHEMICAL BOX MODEL (PBM)

    Science.gov (United States)

    This magnetic tape contains the FORTRAN source code, sample input data, and sample output data for the Photochemical Box Model (PBM). The PBM is a simple stationary single-cell model with a variable height lid designed to provide volume-integrated hour averages of O3 and other ph...

  20. Stone bridges

    Czech Academy of Sciences Publication Activity Database

    Drdácký, Miloš; Slížková, Zuzana

    Prague : Institute of theoretical and applied mechanics AS CR, v.v.i, 2011 - (Drdácký, M.; Binda, L.; Hennen, I.; Kőpp, C.; Lanza, L.), s. 122-129 ISBN 978-80-86246-37-6 Grant ostatní: evropská komise(XE) CHEF-SSPI-044251 Institutional research plan: CEZ:AV0Z20710524 Keywords : flood * stone bridge * cultural heritage Subject RIV: AL - Art, Architecture, Cultural Heritage

  1. Vibration tests on dismounted bridge beams and effects of deterioration

    International Nuclear Information System (INIS)

    This paper aims at describing the tests campaign carried out on five precast bonded post-tensioned concrete bridge beams, recently dismounted after a service life of 50 years. The girders were part of the deck of a recently dismounted viaduct of an Italian motorway. The beams showed different deterioration levels, mainly due to the different exposure to corrosive agents. The test campaign were designed for evaluating the residual load bearing capacity of the members. Dynamic measurements were acquired before and after the static tests by using different excitation sources. This experimental research highlights that the natural frequencies of the beams can be used as a predictor of the ultimate bending moment of an existing structure.

  2. Determination of stability of steel girder structures of large surface mining equipment - calculation of the operating strength factor according to the first revision of TGL 13472

    Energy Technology Data Exchange (ETDEWEB)

    Roessiger, R.

    1987-01-01

    The TGL 13472 industrial standard calculation method is explained for steel girder stability and fatigue with the example of a bucket wheel excavator boom. The excavator operates in block mining with the bucket wheel boom slewing 90 degrees. Bucket wheel cutting and girder load forces are determined by a computer program. Their values are listed. Equations for maximum load fatigue and operating strength factor are given along with stability results. Time required for calculations is regarded as reasonable. 4 refs.

  3. Performance monitoring of a short-span integral-abutment bridge using wireless sensor technology

    Science.gov (United States)

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

    2007-04-01

    Discussed in this paper is the implementation of a wireless sensor system for performance monitoring of bridges. The advanced wireless sensor system, developed at Clarkson University's Laboratory for Intelligent Infrastructure and Transportation Technologies (LIITT), allows for structural monitoring of bridges. A short-span integral-abutment bridge located in New York State is instrumented with a wireless sensor system measuring acceleration, and strain to monitor the behavior of the structure under various loading conditions including ambient, environmental and traffic loading. Strain and acceleration measurements are recorded simultaneously and in real time to validate various performance characteristics of the bridge, including load distribution along an interior girder, as well as additional stiffness factors (end fixity and composite action of the beams and bridge deck), using existing bridge load testing and condition evaluation guidelines used by the New York State Department of Transportation (NYSDOT) and American Association of State Highway and Transportation Officials (AASHTO). Additionally, acceleration measurements are used to extract the superstructure's first five natural frequencies and corresponding mode shapes. Results are compared to a developed Finite Element Method (FEM) model based on the bridge as built drawings.

  4. Decommissioning a small glove box

    International Nuclear Information System (INIS)

    An account is given of dismantling a fuel fabrication glove box using simple tooling. The fissile content of the box was first measured by several non-destructive techniques. After cleaning, the box was dismantled using hand tools and finally packed for disposal. A record of operator radiation doses, the time taken for each stage of the operation and packing information is given. (author)

  5. 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.

  6. 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 satisfactor...... 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....

  7. Experimental Investigation of a Self-Sensing Hybrid GFRP-Concrete Bridge Superstructure with Embedded FBG Sensors

    OpenAIRE

    Wang, Yanlei; Li, Yunyu; Ran, Jianghua; Cao, Mingmin

    2012-01-01

    A self-sensing hybrid GFRP-concrete bridge superstructure, which consists of two bridge decks and each bridge deck is comprised of four GFRP box sections combined with a thin layer of concrete in the compression zone, was developed by using eight embedded FBG sensors in the top and bottom flanges of the four GFRP box sections at midspan section of one bridge deck along longitudinal direction, respectively. The proposed self-sensing hybrid bridge superstructure was tested in 4-point loading to...

  8. Learning with box kernels.

    Science.gov (United States)

    Melacci, Stefano; Gori, Marco

    2013-11-01

    Supervised examples and prior knowledge on regions of the input space have been profitably integrated in kernel machines to improve the performance of classifiers in different real-world contexts. The proposed solutions, which rely on the unified supervision of points and sets, have been mostly based on specific optimization schemes in which, as usual, the kernel function operates on points only. In this paper, arguments from variational calculus are used to support the choice of a special class of kernels, referred to as box kernels, which emerges directly from the choice of the kernel function associated with a regularization operator. It is proven that there is no need to search for kernels to incorporate the structure deriving from the supervision of regions of the input space, because the optimal kernel arises as a consequence of the chosen regularization operator. Although most of the given results hold for sets, we focus attention on boxes, whose labeling is associated with their propositional description. Based on different assumptions, some representer theorems are given that dictate the structure of the solution in terms of box kernel expansion. Successful results are given for problems of medical diagnosis, image, and text categorization. PMID:24051728

  9. 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.

  10. 新型高速铁路专用桥梁检测车的设计方案%Design scheme of bridge-inspection vehicle applies for new high-speed railway bridge

    Institute of Scientific and Technical Information of China (English)

    张效奎; 刘伟; 韩国梁; 李娟娟

    2012-01-01

    In order to solve the problems of new high-speed railway bridge cancel human pavement,the skylight time limit and other characteristics that traditional bridge test equipment maintenance can't reach the detection requirements,a mechanical design plan of new high-speed railway bridge-detection vehicle was investigated. This bridge-detection vehicle uses the structure of fixed gate-type girder,its guiding girder and drive girder walk alternately. This vehicle can detect the onderkant of the bridge and bridge piers with image acquisition technology and can pass the bridge pier automatically without affect the normal train traffic. And its 3D modeling and simulation animation was completed by Solidworks.the virtual prototype was tested. The experimental results show that this design scheme is feasible. This plan will provide reference to more testing and maintenance of railway bridge equipment research and development.%为了解决新型高速铁路桥梁取消人行便道、受“天窗”时间限制等传统桥梁检测维护设备不能达到检测要求的问题,提出了一种新型高速铁路专用桥梁检测车的机械设计方案.该检测车设计采用门式梁固联、导向梁和驱动梁交替行走结构形式;利用图像采集技术实施对高铁桥梁下表面及桥墩的检测;可在不影响列车正常通行的情况下,实现自动过墩.最后,用Solidworks完成了三维建模及动画仿真,并进行了虚拟样机试验.研究结果表明,该设计方案是可行的,为更多高速铁路桥梁检测维护设备研发提供了借鉴和参考.

  11. 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

  12. Aerodynamic stability of long span suspension bridges with low torsional natural frequencies

    DEFF Research Database (Denmark)

    Andersen, Michael Styrk; Johansson, Jens; Brandt, Anders; Hansen, Svend Ole

    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...... 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....

  13. Linear structural stress analysis of a hull girder penetration and a short longitudinal bulkhead using finite element modeling.

    OpenAIRE

    Baumann, Gregg W.

    1997-01-01

    Approved for public release; distribution unlimited. The objective of this study is to investigate structural shadow zones encountered in shipbuilding design using the I-DEAS (Integrated Design Engineering Analysis Software) software. The term 'shadow zone' refers to areas of low stress concentrations that are caused by lines of stress bending around structural discontinuities. Two ship design situations frequently encountered that result in shadow zones are hull girder penetrations and sh...

  14. The possibility of making web tolerance less stringent as prerequisite for achieving economic-fabrication steel girders

    Czech Academy of Sciences Publication Activity Database

    Škaloud, Miroslav; Melcher, J.; Kala, J.; Kala, Z.

    Lisabon : Rolo & Filhos, Indústrias Gráficas, S.A, 2009 - (Ambrósio, J.; Silva, M.), s. 645-646 ISBN 978-989-96264-2-3. [ESMC2009. Lisabom (PT), 07.09.2009-11.09.2009] Grant ostatní: GA ČR(CZ) GA103/08/0275 Institutional research plan: CEZ:AV0Z20710524 Keywords : economic-fabrication steel girders * web initial curvature * straightening Subject RIV: JM - Building Engineering

  15. 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.

  16. 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.

  17. Optimizationd sign fo erhead raveling rane's box irder%桥式起重机箱形梁的优化设计

    Institute of Scientific and Technical Information of China (English)

    田国富; 孙书慧; 程艳辉

    2000-01-01

    箱形梁桥式起重机是起重机械的一种类型,广泛应用于各厂矿企业。其主要承载结构箱形梁的重量占整机重量的比重最大,为提高整机性能,降低能耗,在对整机受力分析基础上,建立了优化模型,并应用其进行了具体优化设计。%The welded box girder of overhead traveling crane is one kind of cranes used in general plants.The welded box girder is the major loaded part and its weight takes the major part of the machine’s total weight.In order to improve the capacity of the cranes, a kind of optimization model based on the analyzing of loading condition and a optimization design according to it is done.

  18. 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.

  19. Experimental study on wind-rain-induced and vortex-induced vibration in bridge deck sections of long-span bridges%大跨度桥梁主梁风雨致涡激振动试验研究

    Institute of Scientific and Technical Information of China (English)

    辛大波; 张明晶; 王亮; 欧进萍; 李惠

    2011-01-01

    针对风雨联合作用下的大跨桥梁风雨致涡激振动问题,以某一分离式双箱主梁桥梁及其闭口主梁型式桥梁为研究对象,通过在大气边界层风洞中搭建风雨联合作用试验系统,完成风雨联合作用下大跨桥梁节段模型涡激振动试验. 试验结果显示:不同雨强下,开口节段模型涡激振动的起振风速及锁定风速基本一致,但最大振动幅值有一定差别.不同雨强下,闭口节段模型随机振动的振动时程有一定差别,且随着风速增大,振动幅值增大.开口节段模型风雨联合作用下的位移幅值大于单一风作用下的位移幅值,最大增量可达1/4.得出结论:降雨增大了桥梁主梁涡激振动幅值;闭口节段模型相对开口节段模型在抵抗涡激振动方面性能更优良.%The vortex-induced vibration test in bridge deck sections of long-span bridges was carried out by considering vortex-induced vibration characteristics under the simultaneous actions of wind and rain, taking a separated twin-box girder bridge and its closed form as research objects. A system of simultaneous actions of wind and rain built in an atmospheric boundary layer wind tunnel was also utilized. Experimental results display that the wind speed at the start of oscillation and the wind speed of the lock-in region for the slotted section model show no difference in various rainfall intensities, but the maximal amplitudes of vortex-excited resonance display some differences. The time histories of stochastic vibration for the closed section model have some differences in various rainfall intensities, and the amplitude of vibration increases with rising wind speed. The displacement amplitude under the simultaneous actions of wind and rain is larger than the displacement amplitude under a single wind load; the highest increment reaches one quarter. Experimental results also show that the amplitude of vortex-induced vibration in bridge deck sections is increased by

  20. New bridge circuit-type detector to measure precise resistance change of strain gauge at low temperature and magnetic field

    OpenAIRE

    Ohashi, Masashi; Kishii, Nobuya; Tateno, Shota

    2016-01-01

    We report a new highly accurate and versatile bridge-circuit-type detector that has a simple structure and demonstrates a low degree of error for measurements of thermal expansion and magnetostriction by the strain gauge method. As an example, a commercial physical property measurement system (PPMS) is combined with a compact bridge-circuit box. Thermal expansion and magnetostriction are calculated from the resistance of the bridge and bridge voltage, measured by the operation of a standard P...

  1. Glove-box filters

    International Nuclear Information System (INIS)

    Description is given of a device for simply and rapidly assembling and dissassembling the filters used inside sealed enclosures, such as glove-boxes and shielded cells equipped with nippers or manipulators, said filters being of the type comprising a cylindrical casing containing a filtering member, the upper portion of said casing being open so as to allow the gases to be cleaned to flow in, whereas the casing bottom is centrally provided with a hole extended outwardly by a threaded collar on which is screwed a connecting-sleeve to be fixed to the mouth of a gas outlet pipe. To a yoke transverse bar is welded a pin which can be likened to a bent spring-blade, one arm of which welded to said transverse bar, is rectilinear whereas its other arm is provided with a boss cooperating with a cavity made in a protrusion of said pipe, right under the mouth thereof

  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. 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...

  4. 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。

  5. 粘钢加固损伤混凝土箱型桥墩的抗震性能Ⅰ:双向拟静力试验%Anti-seismic properties of damaged concrete bridge piers with hollow box-section strengthened with adhering steel plates Ⅰ:bi-directional quasi-static test

    Institute of Scientific and Technical Information of China (English)

    宗周红; 邓江东; 黎雅乐; 刘爱荣

    2013-01-01

    11 scaled models of reinforced concrete bridge piers with hollow box-section were de-signed and fabricated in the lab.Bi-directional quasi-static tests for these scaled pier models strength-ened with adhering steel plates were carried out.Several seismic performance indicators, such as load-displacement hysteretic and skeleton curves, ductility, degradation of rigidity, and energy dissi-pation were investigated.The experimental results show that all the strengthened piers present typical flexural failure modes, and plastic hinge appears in the superior margin of steel plates in stead of in the bottom for piers without strengthening.The improvement of anti-seismic properties exhibits that it was an effective method to change the plastic hinge position by adhering steel plates.The load ca-pacity and the lateral rigid along the strong axis direction are greater, while the energy dissipation a-long the weak axis direction is stronger.The hysteretic curves of the weak axis exhibit notable pinch effects.The initial damage only has small effect on the degradation of rigidity and energy dissipation of the strengthening piers.Meanwhile, the changes of axial compression ratio and slenderness ratio have a great impact on the seismic performance.With the increase of the axial compression ratio, the carrying capacity, the ductility performance and energy dissipation of models increase, but the ulti-mate displacement decreases.With the decrease of the slenderness ratio, the carrying capacity of piers strengthened with adhering steel plates increases;however the ultimate deformation capacity de-creases, while the degradation of rigidity becomes more serious.%设计制作了11个钢筋混凝土箱型截面桥墩缩尺模型,对其进行了粘钢加固后的双向拟静力试验,分析了加固桥墩的荷载位移滞回曲线、骨架曲线、延性能力、刚度退化和耗能能力等。结果表明,加固墩柱均发生以弯曲破坏为主的延性破坏,破坏塑性

  6. Thermal Bridges in Building Construction - Measurements and Calculations

    DEFF Research Database (Denmark)

    Rose, Jørgen

    The thesis investigates detailed calculation methods for evaluating heat loss through building envelope constructions, or more specific, thermal bridges. First a detailed description of the calculation methods, i.e. both calculation programs and guidelines, for calculating typical thermal bridges...... detailed calculations in more operational and applicable projecting tools, e.g. thermal bridge catalogues or U-value tables....... in building envelope constructions is given. After this a validation of both programs and guidelines is presented. The validation is performed by comparing calculated U-values with Guarded Hot Box measurements. The last part of the thesis discusses the possibilities of utilising the results of...

  7. Cardboard Boxes: Learning Concepts Galore!

    Science.gov (United States)

    Warner, Laverne; Wilmoth, Linda

    2007-01-01

    Mrs. Keenan, a preschool teacher, observed her 3-year-old granddaughter Riley pull, tug, and stack piles of holiday boxes on the floor. She remembered that her child care director had suggested using boxes as a curriculum theme, but she hadn't given much thought about the idea until now. She said to herself, "I wonder if my children would be as…

  8. 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...

  9. 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.

  10. Students' approaches to mathematical tasks using software as a black-box, glass-box or open-box

    OpenAIRE

    Hosein, Anesa

    2009-01-01

    Three mathematical software modes are investigated in this thesis: black-box software showing no mathematical steps; glass-box software showing the intermediate mathematical steps; and open-box software showing and allowing interaction at the intermediate mathematical steps. The glass-box and open-box software modes are often recommended over the black-box software to help understanding but there is limited research comparing all three. This research investigated students' performance and the...

  11. 考虑桩-土相互作用的多年冻土区多跨简支梁桥地震响应分析%SEISMIC RESPONSE ANALYSIS OF MSSS BRIDGE IN PERMAFROST INCLUDING PILE-SOIL INTERACTION

    Institute of Scientific and Technical Information of China (English)

    李永波; 张鸿儒; 郜新军

    2012-01-01

    To investigate the seismic response of MSSS (multi-span simply supported) bridge of Qinghai-Tibet Railway in a permafrost zone, Proper 3D analytical models of a 10x32m box girder MSSS Bridge are presented. The group pile-soil interaction is represented by equivalent foundation springs while the pounding effect of adjacent vibration units at the expansion joints is simulated by spring-damper elements. This paper studies the effects of thawed soil thickness, wave passage and pounding on seismic behaviours of the MSSS Bridge. it found that the stiffness of equivalent springs decreases with thawed soil thickness increase, seismic damages such as unseating failure and pier overturning more easily occur under a strong seismic action. The pounding occurs when the relative distance exceeds the gap distance between adjacent vibration units, which depends on the velocity of seismic wave and travel distance. When the velocity is low, the pounding effect is obvious and influences the seismic response of a bridge significantly, which can induce unseating failure very easily. Moreover, a bridge abutment also plays an important role in seismic response of a bridge system. Therefore, damages which may occur in summer under low wave velocity should be emphasized in the seismic assessment for MSSS bridges in a permafrost zone.%为分析青藏铁路多年冻土区多跨简支梁桥地震响应情况,建立了一座10x32m箱形多跨简支梁桥三维全桥模型,以等效基础弹簧考虑桩.土相互作用;以具有初始间隙的并联弹簧.阻尼单元模拟伸缩缝两端结构的碰撞,研究了冻土融化深度、行波效应及碰撞效应对多跨简支桥梁结构地震响应的影响。结果表明:随着融土下限加深,等效基础弹簧刚度明显减小,在强地震动作用下,桥梁结构易发生落梁、桥墩倾覆等震害;当相邻碰撞体的相向位移超过伸缩缝宽度时两者发生碰撞,碰撞次数及碰撞力随地震动

  12. Method of positioning channel box

    International Nuclear Information System (INIS)

    Upon measuring the dimension of a channel box by disposing ultrasonic sensors to the uppermost portion of a measuring device main body, the deviation of the channel box from the center of the device main body is detected by measuring the distance betwen the sensors at the uppermost portion of the device main body and the lower end of the channel box for four surfaces simultaneously. The direction and the distance for moving the channel box to the center of the device main body are calculated based on the results to feedback tham for the operation of a fuel exchanger, thereby positioning the channel box upon insertion to the device main body. That is, a fuel assembly loaded with the channel box is gradually brought down being suspended from a crane and the position of the channel box is recognized by the ultrasonic sensors, thereafter, the position of the center is corrected and it is brought down again and the outer dimension is measured. Accurate positioning in a short periodof time is enabled and operator's burden can be mitigated to prevent the danger of indury. (N.H.)

  13. AE application for the flaw detection of steel bridge members

    International Nuclear Information System (INIS)

    Acoustic emission technique was employed for the feasible study of the inspection of steel bridge structure. For this experiment, full scale I-plate girder steel bridge member, which had the size of 5 m x 2.34 m x 1.25 m length, width and height respectively, was constructed in laboratory. The real cracks which were pre-cracked in the end of stiffener as well as the pencil lead break AE sources were used for locating sources. Before doing source location work, the characteristics of wave propagation in the entire structure were investigated and the measurement of attenuation and velocity in the web plate was carried out. We tried to do post filtering work for several parameters such as peak amplitude, time, clustering etc.. As a results it gave very good location without scattering. And also waveform and spectrum analysis for the real crack signals gave a valuable information. Consequently, good source location results including scattering location were obtained from this experiment.

  14. Microclimate boxes for panel paintings

    DEFF Research Database (Denmark)

    Wadum, Jørgen

    The use of microclimate boxes to protect vulnerable panel paintings is, therefore, not a new phenomenon of the past two or three decades. Rather, it has been a concern for conservators and curators to protect these objects of art at home and in transit since the end of the nineteenth century. The...... increased number of travelling exhibitions in recent years has heightened the need to protect paintings during circulation (Thomson 1961; Mecklenburg 1991). The use and design of microclimate boxes have been evolving since 1892. These boxes may be divided into three broad groups: those using an active...

  15. Two-dimensional box plot

    OpenAIRE

    Phattrawan Tongkumchum

    2005-01-01

    In this paper we propose a two-dimensional box plot, a simple bivariate extension of the box plot and the scatter plot. This plot comprises a pair of trapeziums oriented in the direction of a fitted straight line, with symbols denoting extreme values. The choice for the fitted straight resistant line showing the relationship between the two variables is Tukey’s resistance line. The main components of the plot are an inner box containing 50% of the projection points of the observations on the ...

  16. The behaviour and design of the webs of economic-fabrication steel girders used in composite construction

    Czech Academy of Sciences Publication Activity Database

    Škaloud, Miroslav; Zörnerová, Marie

    Singapore : Research publishing services, 2009 - (Lam, D.), s. 166-171 ISBN 978-981-08-3068-7. [Steel concrete composite and hybrid structures. Leeds (GB), 08.07.2009-10.07.2009] R&D Projects: GA ČR(CZ) GA103/06/0064; GA AV ČR(CZ) IAA200710603 Grant ostatní: GA ČR(CZ) GA103/08/0275; GA ČR(CZ) GA103/08/1677 Institutional research plan: CEZ:AV0Z20710524 Keywords : economic-fabrication steel girders * buckling * fatigue Subject RIV: JM - Building Engineering

  17. GPR signal analysis of post-tensioned prestressed concrete girder defects

    International Nuclear Information System (INIS)

    The accurate inspection of the duct condition in post-tensioned prestressed concrete (PPC) is an essential part of GPR concrete inspection. The purpose is to inspect the grouting condition of the ducts where the strands are located, to find out if there is a void in the ducts, and if any water exists. In order to investigate the radar image characteristics of different PPC duct defects, a number of model girders were manufactured. Three major ducts are included in our study: (1) well grouted and no void (normal condition); (2) the duct is half filled, and the void is filled by water or air; and (3) the duct is not filled at all, and the duct is water or air filled. The data corresponding to seven different situations are acquired and processed. It is found that the radar can detect the first interface in the duct, and the detailed structure inside the duct cannot be ‘seen’ from the images directly. Characteristic curves greatly help the interpretation. A completely void duct is the easiest to differentiate from the others. The signature for this situation is characterized by a strong and clear reflection interface which becomes weaker as the void is water filled. The normal condition shows the weakest reflection interface. As for the half void situation, the front scan shows a similar result to the normal condition whether it is water or air filled, and the back scan shows similar features to the completely void situation. The experiment and analysis is helpful and instructive for practical engineering inspection. (paper)

  18. Static and fatigue investigation of second generation steel free bridge decks

    International Nuclear Information System (INIS)

    This paper outlines the static and fatigue behavior of two different cast-in-place second generation steel-free bridge decks, which are: hybrid carbon fiber reinforced polymer (CFRP); and glass fiber reinforced polymer (GFRP) and steel strap design. Although cast monolithically, the first deck slab was divided into three segments with different reinforcement configurations. All three segments were tested under a 222kN cyclic loading to investigate fatigue behavior. The second bridge deck comprised an internal panel and two cantilevers and was equipped with a civionics system. The internal panel static test that this paper deals with is useful in the development of fatigue theory derived from fatigue testing of the first bridge deck. Test results form the cyclic loading of the first bridge deck indicated that the cross-sectional area of the reinforcement used in the test bridge deck can be reduced by 40% based on the reinforcement provided in the deck under service loads. The hybrid system also reduced the development of longitudinal crack widths to approximately 0.4 mm under service conditions, compared to the cracks that occurred approximately halfway between adjacent bridge girders that were determined to be roughly 1 mm in several first generation steel-free bridge decks constructed in Canada. Civionics, also discussed in the paper, is a new term coined from Civil-Electronics, which is the application of electronics to civil structures. The Civionics Specifications (2004) developed by ISIS Canada researchers are a helpful design tool for engineers and contractors to develop civionics and structural health monitoring systems for civil infrastructure that will last the lifetime of a structure. The use of civionics for the second test bridge deck ensured the survival of 100% of the 63 internal sensors throughout the rigors of the construction and casting of the deck. (author)

  19. Puentes extradosados: evolución y tendencias actuales

    Directory of Open Access Journals (Sweden)

    José Miguel Benjumea Royero

    2012-09-01

    Full Text Available Since their appearance in 1994, extradosed bridges have played an important role in road and railway projects, competing (in medium span lengths with cables-stayed and prestressed box girder bridges. At a regional level, extradosed bridges have been implemented more frequently in Asia, but recent projects developed in Europe and America show a growing interest in this typology. Consequently, this paper is aimed at offering a survey viewpoint on the evolution of extradosed bridges, from their origin to their current applications. This paper is also intended to show the adopted structural trends by presenting existing extradosed bridges, bridges under construction, and newly designed bridges. Finally, the main advantages and disadvantages of this type of bridges are analyzed and compared to cable-stayed and prestressed box girder bridges.

  20. Myiasis in two box turtles.

    Science.gov (United States)

    Gould, W J; Georgi, M E

    1991-10-15

    Two eastern box turtles (Terrapene carolina carolina) were treated for myiasis caused by Sarcophaga cistudinis. The tortoises were examined because of swellings of the proximal cervical regions. Both fully recovered following surgical removal of multiple larvae. PMID:1748614

  1. 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.

  2. 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.

  3. 汶川地震桥梁震害经验及抗震研究若干新进展%Lessons Learned from Wenchuan Seismic Damages and Recent Research on Seismic Design of Highway Bridges

    Institute of Scientific and Technical Information of China (English)

    王东升; 孙治国; 郭迅; 李晓莉; 霍燚

    2011-01-01

    The great Wenchuan earthquake, which measured as 8. 0 Ms and occurred on May 12, 2008 in Sichuan province of China, has caused severe damage to many highway bridges and also left us with valuable information that can be analyzed to reduce potential losses associated with future earthquakes. The Lessons learned from Wenchuan seismic damages of highway bridges were summarized. It is believed that special attention should be paid to (1) bridge seismic response and unseating damages subjected to near-fault ground motions; ( 2 ) preventive design of collapse damage of curved girder bridges with small radius; ( 3 ) ductility and seismic design, detailed reinforcement of bridges and seismic damage control of high-rise piers under deep water. The recent research progress of our research team on seismic performance of highway bridges was summarized. It includes design idea and method of unseating protection of highway bridges, deformation capacity and shear strength of PC bridge piers, numerical simulation of seismic damage mechanism of curved girder bridges, and countermeasures to prevent collapse of curved girder bridges with small radius.%2008年5月12日我国四川省汶川县发生8.0级大地震,造成大量公路桥梁破坏,并为桥梁抗震研究留下了众多资料.总结了汶川地震桥梁震害经验,认为宜重视桥梁近断层地震动响应及防落梁措施、小半径曲线梁桥地震防倒塌设计、桥梁延性抗震设计及细部配筋和深水高桥墩地震损伤及控制等抗震问题.综述了课题组近些年对桥梁抗震研究的若干新进展,包括梁式桥防落梁抗震设计理念及方法、钢筋混凝土桥墩地震抗剪强度及变形能力研究、曲线梁桥地震破坏机理数值分析与小半径曲线梁桥地震防倒塌设计对策等.

  4. Thinking Outside the Box

    International Nuclear Information System (INIS)

    The World Nuclear Transport Institute was formed to fill a need to provide a dedicated vehicle for the radioactive transport and packaging industry sectors worldwide, to exchange information and ideas, all with a view to working toward consolidated industry positions on the key issues affecting safe, efficient and reliable transport. WNTI was also intended to be a strong voice for industry in those international and national bodies where deliberations on such transport safety issues take place. The very fact that companies, sometimes in competition with each other, were prepared to come together in this way, reflects two important points: firstly, it represents an acknowledgement on industry's part that safe, effective and reliable transport is the sine qua non, the absolute essential. And second, it is a recognition that it is enhanced to the extent that industry is able to collaborate to this end. This is thinking outside the box. Another important attribute of safety is 'stability'. Everyone likes to know where he or she stands. The radioactive materials packaging and transport industry thrives within a stable regulatory framework for safety. For a stable regulatory regime allows operators to be properly trained; it allows operators to become familiar with safety requirements, and to be at ease with them. Stability is conducive to safety and efficiency. Stability is good for business too - for stability in package and transport requirements allows sufficient time for a fair return on investment in expensive package design, manufacture, licensing and use over time. Stability should not, however, be opposed to creativity. From experience we can develop new thinking to improve efficiency as illustrated in examples of work related to the packaging and transport of Uranium Concentrates for instance.. Another example is work within WNTI on the thermal test requirements for the packaging of uranium hexafluoride. The robustness of packages is based on the risk factors

  5. Comparison of black-box, glass-box and open-box software for aiding conceptual understanding

    OpenAIRE

    Hosein, Anesa; Aczel, James; Clow, Doug; Richardson, John T. E.

    2008-01-01

    Three mathematical software types: black-box (no steps shown), glass-box (steps shown) and open-box (interactive steps) were used by 32 students to solve conceptual and procedural tasks on the computer via remote observation. Comparison of the three software types suggests that there is no difference in the scores that students receive for conceptual understanding tasks. Students using the black-box are more likely to explore answers than students using the glass and open-box software.

  6. 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.

  7. Effects of Live Load on Seismic Response of Bridges: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Sanders D.H.

    2012-01-01

    Full Text Available Although live load is well known to have a dynamic effect on bridge response in addition to its self-weight, the significance of these effects on seismic response is unclear. In addition, most bridge design specifications have few requirements concerning the inclusion of live load in their seismic design provisions. The main objective of this study is therefore to investigate and obtain insight into the effect of vehicle-bridge interaction during earthquake shaking. The study consists of both experimental and analytical investigations. This paper focuses on the experimental work, which includes shake table testing of a 2/5-scale model of a horizontally curved steel girder bridge loaded with a series of representative vehicles. Preliminary experimental results show that the presence of the live load had a clear beneficial effect on performance for small amplitude motions, but that this improvement diminished with increasing amplitude of shaking. Parameters used to measure performance include column displacements, abutment shear forces, abutment uplift, and concrete spalling.

  8. The influence of rainfall on the static characteristics of bridge deck sections%降雨对桥梁主梁静力特性的影响

    Institute of Scientific and Technical Information of China (English)

    辛大波; 王亮; 李惠; 欧进萍

    2012-01-01

    The three influencing factors of wind-rain-induced static forces were analyzed aiming at the phenomenon of simultaneous actions of wind and rain for long-span bridge decks, based on the analysis of static load on the bridge deck section. The test method of the increment of wind-rain-induced static forces in joint wind and rain comparing to wind-induced static forces in single wind is given. The wind-rain-induced static characteristics test was carried out in the surroundings of simultaneous actions of wind and rain built in the atmospheric boundary layer wind tunnel, taking a twin-separated box girder as research object. The influencing rule of rainfall on the wind-induced static forces of bridge deck sections was obtained. Experimental results display the effect of impact force of rain on the wind-induced drag force of bridge deck sections is dominant in the large negative angle of attack of circumstances. The effect of change of flow field and water film on the surface of bridges on the wind-induced drag force of bridge deck sections is dominant in the small negative and positive angle of attack of circumstances. The gravity of raindrops, impact force of rain, change of flow field and water film on the surface of bridges all have certain contribution on the wind-induced lift force of bridge deck sections. The change of flow field and water film on the surface of bridges play the most important role on the wind-induced pitching moment of bridge deck sections, followed by the gravity of raindrops, finally is the impact force of rain. The result shows that the effect of rainfall on the wind-induced static forces of bridge deck sections is mainly depended on the change of flow field and water film on the surface of bridges.%针对大跨桥梁主梁风雨联合作用现象,从静力学角度出发,分析风雨联合作用下桥梁主梁荷载的三个组成成分——风雨致静力三组分,以及桥梁主梁风雨致静力相对于纯

  9. 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.

  10. 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.

  11. Structural Aspects of Railway Truss Bridges Affecting Transverse Shear Forces in Steel-Concrete Composite Decks

    Directory of Open Access Journals (Sweden)

    Siekierski Wojciech

    2015-03-01

    Full Text Available 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.

  12. 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.

  13. Asymptotic symmetries from finite boxes

    Science.gov (United States)

    Andrade, Tomás; Marolf, Donald

    2016-01-01

    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 Poincaré 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 AdS3 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.

  14. 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.

  15. Puentes extradosados: evolución y tendencias actuales

    OpenAIRE

    José Miguel Benjumea Royero; Gustavo Chio Cho; Esperanza Maldonado Rondón

    2012-01-01

    Since their appearance in 1994, extradosed bridges have played an important role in road and railway projects, competing (in medium span lengths) with cables-stayed and prestressed box girder bridges. At a regional level, extradosed bridges have been implemented more frequently in Asia, but recent projects developed in Europe and America show a growing interest in this typology. Consequently, this paper is aimed at offering a survey viewpoint on the evolution of extradosed bridges, from their...

  16. The Type and Construction Development of Modern Bridge Construction%现代桥梁建筑的类型及建设发展展望

    Institute of Scientific and Technical Information of China (English)

    崔超

    2015-01-01

    Bridge construction is important to economic development,people's life and national defense.The main types of modern bridge are slab bridge,girder bridge and cable stayed bridge.The design and construction ability of bridge in our country rank high all over the world,bridge construction in our country has achieved great accomplishment.%桥梁建筑对于国民经济发展、人民生产生活及巩固国防等都具有非常重要的作用.现代桥梁的主要类型有板式桥、梁式桥及斜拉桥等.我国桥梁设计、施工水平和能力已跃入世界先进行列,桥梁建设已取得巨大成就.但我国幅员辽阔,桥梁建设发展的任务还艰巨.

  17. RESEARCH ON KEY TECHNOLOGY IN CONSTRUCTING FRP-STEEL COMPOSITE BRIDGE%FRP-钢组合结构桥梁建造关键技术研究

    Institute of Scientific and Technical Information of China (English)

    朱坤宁; 万水

    2011-01-01

    对FRP-钢组合结构公路桥研制过程中的关键技术进行了研究,通过GFRP桥面板的设计与加工、有限元分析和试验研究,研制出适用于我国公路桥梁用的重型FRP桥面板.将GFRP桥面板与波形腹板H型钢梁组合起来,建成我国第一座FRP-钢组合结构公路桥.对GFRP-钢组合结构公路桥梁结构进行成桥荷载试验.试验结果表明,FRP-钢组合结构桥梁处于安全受力状态,满足设计荷载下的使用要求.%The construction technology of FRP-steel composite bridge is researched through the development process. The FRP bridge deck that used in bridge structure is developed through the design and fabricate, as well as the finite element analysis and experimental research of GFRP bridge deck. And the first FRP-steel composite bridge in China is built with GFRP bridge deck and steel H girder with corrugated web. Load test of the composite bridge is made, and the result shows that the structure is in a safe state and meets the requirements under the design load.

  18. RESEARCH ON KEY TECHNOLOGY IN CONSTRUCTING FRP-STEEL COMPOSITE BRIDGE%FRP-钢组合结构桥梁建造关键技术研究

    Institute of Scientific and Technical Information of China (English)

    朱坤宁; 万水

    2011-01-01

    The construction technology of FRP-steel composite bridge is researched through the development process. The FRP bridge deck that used in bridge structure is developed through the design and fabricate, as well as the finite element analysis and experimental research of GFRP bridge deck. And the first FRP-steel composite bridge in China is built with GFRP bridge deck and steel H girder with corrugated web. Load test of the composite bridge is made, and the result shows that the structure is in a safe state and meets the requirements under the design load.%对FRP-钢组合结构公路桥研制过程中的关键技术进行了研究,通过GFRP桥面板的设计与加工、有限元分析和试验研究,研制出适用于我国公路桥梁用的重型FRP桥面板.将GFRP桥面板与波形腹板H型钢梁组合起来,建成我国第一座FRP-钢组合结构公路桥.对GFRP-钢组合结构公路桥梁结构进行成桥荷载试验.试验结果表明,FRP-钢组合结构桥梁处于安全受力状态,满足设计荷载下的使用要求.

  19. Generalized Gaussian Bridges

    CERN Document Server

    Sottinen, Tommi

    2012-01-01

    A generalized bridge is the law of a stochastic process that is conditioned on linear functionals of its path. We consider two types of representations of such bridges: orthogonal and canonical. In the canonical representation the filtrations and the linear spaces generated by the bridge process and the original process coincide. In the orthogonal representation the bridge is constructed from the entire path of the underlying process. The orthogonal representation is given for any continuous Gaussian process but the canonical representation is given only for so-called prediction-invertible Gaussian processes. Finally, we apply the canonical bridge representation to insider trading by interpreting the bridge from an initial enlargement of filtration point of view.

  20. Concrete bridge prioritization system

    OpenAIRE

    Kesselring, Debbie Anne

    1995-01-01

    An alternative method of prioritization for concrete bridge maintenance, repair, and rehabilitation activities is required due to the inability of the current system to manage the increasing nmnber of aging concrete bridges. The Concrete Bridge Prioritization System was proposed because of its ability to address the critical technical parameters of safety and cost benefit in prioritization of funding and work allocation. The analysis includes four parts, service life assessment, s...

  1. Innovations in Los Alamos alpha box design

    International Nuclear Information System (INIS)

    Destructive examinations of irradiated fuel pins containing plutonium fuel must be performed in shielded hot cells with strict provisions for containing the plutonium. Alpha boxes provide containment for the plutonium, toxic fission products, and other hazardous highly radioactive materials. The alpha box contains windows for viewing and a variety of transfer systems specially designed to allow transfers in and out of the alpha box without spread of the hazardous materials that are contained in the box. Alpha boxes have been in use in the Wing 9 hot cells at Los Alamos National Laboratory for more than 20 years. Features of the newly designed alpha boxes are presented

  2. Innovations in Los Alamos alpha box design

    Energy Technology Data Exchange (ETDEWEB)

    Ledbetter, J.M.; Dowler, K.E.; Cook, J.H.

    1985-01-01

    Destructive examinations of irradiated fuel pins containing plutonium fuel must be performed in shielded hot cells with strict provisions for containing the plutonium. Alpha boxes provide containment for the plutonium, toxic fission products, and other hazardous highly radioactive materials. The alpha box contains windows for viewing and a variety of transfer systems specially designed to allow transfers in and out of the alpha box without spread of the hazardous materials that are contained in the box. Alpha boxes have been in use in the Wing 9 hot cells at Los Alamos National Laboratory for more than 20 years. Features of the newly designed alpha boxes are presented.

  3. 嘉绍大桥主墩双壁钢围堰施工技术%Construction Techniques of Double-Wall Steel Cofferdams for Main Piers of Jiashao Bridge

    Institute of Scientific and Technical Information of China (English)

    宋华清; 唐衡; 林道锦

    2012-01-01

    The main shipping channel bridge of the Jiashao Bridge is a steel box girder cable-stayed bridge with six pylons and four cable planes and the six pile caps of the main piers of the bridge were constructed by the double-wall steel cofferdams. The maximum diameter of the cofferdams is 43. 65 m, the spacing distance between the inner and outer walls of a cofferdam is 1. 5 m, the height of the cofferdam is 26 m and additionally a cofferdam was also provided with eight groups of the combined guiding and positioning devices (guiding piles-sliding steel brackets) arranged in a center-tocenter symmetric way. All cofferdams were manufactured piece by piece in the workshop and at a pier site, the assembling platform for the cofferdam was set up in between the steel casings and platform piles and the cofferdam was well assembled in one time by the gantry carne, using the pier site assembling construction technology. The cofferdam was then lowered down by the sinking system synchronously controlled by computer and was sunk down in place by the aid of the unbalanced ballast and the "inverse pan" dredging. Practice proves that the six cofferdams for the main piers of the bridge have been finally smoothly sunk down in place. The plan deviations of the cofferdams are 50~90 mm and the perpendicularity is less than 1/400, which all satis.fy the relevant requirements in the codes.%嘉绍大桥主航道桥为六塔四索面钢箱梁斜拉桥,6个主墩承台均采用双壁钢围堰方案施工.钢围堰最大直径43.65m,内、外壁间距1.5m,高26 m,以中心对称的方式布设8组组合导向定位装置(导向桩+滑动钢牛腿).钢围堰在加工场内分片制作,在钢护筒与平台桩间搭设拼装平台,采用原位拼装工艺,利用龙门吊一次组拼成型;采用计算机同步控制下沉系统下放,辅以不均衡配载和“倒锅底形”吸泥工艺下沉到位.实践证明,该桥6个主墩钢围堰均顺利下沉到位,平面偏位50~90 mm

  4. Partons of a spherical box

    International Nuclear Information System (INIS)

    Calculation of parton distributions in the 'cavity approximation' to the MIT bag model gives a divergent sum of positive terms. In this version of the model the flexible movable bag is replaced by an inflexible immovable box. This suggests that Bjorken scaling does not hold for the deep inelastic scattering in this version of the model. (K.A.)

  5. On the Dirichlet's Box Principle

    Science.gov (United States)

    Poon, Kin-Keung; Shiu, Wai-Chee

    2008-01-01

    In this note, we will focus on several applications on the Dirichlet's box principle in Discrete Mathematics lesson and number theory lesson. In addition, the main result is an innovative game on a triangular board developed by the authors. The game has been used in teaching and learning mathematics in Discrete Mathematics and some high schools in…

  6. A Box Full of Kisses

    Institute of Scientific and Technical Information of China (English)

    崔增印

    2008-01-01

    The story goes that some time ago,a man pun- ished his 3-year-old daughter for wasting a roll of gold wrapping paper.Money was tight and he became infuriated when the child tried to decorate a box to put under the Christmas tree.Nevertheless,the little girl brought the gift to

  7. Bridging the Gap

    DEFF Research Database (Denmark)

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska;

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures.......Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures....

  8. Bridging the Gap

    OpenAIRE

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska; Murdock, Karen; Schmidt, Iben Julie

    2015-01-01

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures. Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ve...

  9. Post-buckled behaviour, its partial erosion and fatigue limit state in steel girders subjected to many times repeated loading

    Czech Academy of Sciences Publication Activity Database

    Škaloud, Miroslav; Zörnerová, Marie

    Brno : Akademické nakladatelství CERN, s.r.o. 2009, 2009 - (Melcher, J.; Skyva, J.; Karmazínová, M.), s. 293-302 ISBN 978-80-7204-635-5. [Ocelové konstrukce a mosty 2009. Brno (CZ), 23.09.2009-25.09.2009] R&D Projects: GA ČR(CZ) GA103/09/0091 Grant ostatní: GA ČR(CZ) GA103/08/0275; GA ČR(CZ) GA103/08/1677 Institutional research plan: CEZ:AV0Z20710524 Keywords : thin-walled steel girders * buckling * S-N curves Subject RIV: JM - Building Engineering

  10. On the Effect of Hull Girder Flexibility on the Vertical Wave Bending Moment for Ultra Large Container Vessels

    DEFF Research Database (Denmark)

    Andersen, Ingrid Marie Vincent; Jensen, Jørgen Juncher

    2012-01-01

    the ship. The theory takes into account non-linear radiation forces (memory effects) through the use of a set of higher order differential equations. The non-linear hydrostatic restoring forces and non-linear Froude-Krylov forces are determined accurately at the instantaneous position of the ship in...... global hull girder loads as consequence of the increased hull flexibility must be considered. This is especially so as the rules of the classification societies do not explicitly account for the effect of hull flexibility on the global loads. In the present paper an analysis has been carried out for the...... 9,400 TEU container ship used as case-ship in the EU project TULCS (Tools for Ultra Large Container Ships). A non-linear time-domain strip theory is used for the hydrodynamic analysis of the vertical bending moment amidships in sagging and hogging conditions for a flexible and a rigid modelling of...

  11. Estimation of Tsunami Bore Forces on a Coastal Bridge Using an Extreme Learning Machine

    Directory of Open Access Journals (Sweden)

    Iman Mazinani

    2016-04-01

    Full Text Available This paper proposes a procedure to estimate tsunami wave forces on coastal bridges through a novel method based on Extreme Learning Machine (ELM and laboratory experiments. This research included three water depths, ten wave heights, and four bridge models with a variety of girders providing a total of 120 cases. The research was designed and adapted to estimate tsunami bore forces including horizontal force, vertical uplift and overturning moment on a coastal bridge. The experiments were carried out on 1:40 scaled concrete bridge models in a wave flume with dimensions of 24 m × 1.5 m × 2 m. Two six-axis load cells and four pressure sensors were installed to the base plate to measure forces. In the numerical procedure, estimation and prediction results of the ELM model were compared with Genetic Programming (GP and Artificial Neural Networks (ANNs models. The experimental results showed an improvement in predictive accuracy, and capability of generalization could be achieved by the ELM approach in comparison with GP and ANN. Moreover, results indicated that the ELM models developed could be used with confidence for further work on formulating novel model predictive strategy for tsunami bore forces on a coastal bridge. The experimental results indicated that the new algorithm could produce good generalization performance in most cases and could learn thousands of times faster than conventional popular learning algorithms. Therefore, it can be conclusively obtained that utilization of ELM is certainly developing as an alternative approach to estimate the tsunami bore forces on a coastal bridge.

  12. 沪蓉高速公路铁罗坪大桥设计%Design of Tieluoping Bridge on Shanghai-Chengdu Expressway

    Institute of Scientific and Technical Information of China (English)

    郭安辉; 张门哲

    2012-01-01

    铁罗坪大桥主桥为预应力混凝土双塔双索面斜拉桥,跨径布置为(140+322+140)m.该桥主梁基本断面形式为边主梁;桥塔为H形,总高190.397 m,塔柱采用空心五边形断面,在上塔柱锚固区采用U形预应力束加强,桥塔墩基础由24根φ2.4m的桩基组成;每个桥塔两侧布置19对斜拉索,斜拉索采用低松弛镀锌高强钢丝.从温度作用、汽车荷载作用、成桥阶段稳定系数方面对2种结构体系(墩塔梁固结体系和飘浮体系)进行比选,最终选择了对结构受力更为有利的墩塔梁固结体系.采用MIDAS Civil软件分别对该桥静、动力特性、抗风稳定性及地震反应进行分析,分析结果表明结构受力均满足规范要求.该桥主梁采用悬臂浇筑施工,合龙顺序为先边跨、再中跨.%The main bridge of the Tieluoping Bridge on Shanghai-Chengdu Expressway is a prestressed concrete cable-stayed bridge with double pylons, double cable planes and with span arrangement (140 + 322 + 140) m. The basic section of the main girder of the bridge is the section of edge main girders and the pylons are the H-shape ones, each being 190. 397 m in total height. The columns of a pylon were designed as the hollow pentagonal sections and in the anchorage zones in the upper parts of the columns, the U-shape prestressing strands were employed to reinforce the zones. A foundation for the pylon piers is composed of 24 nos. of f2. 4 m piles. On both sides of a pylon, 19 pairs of stay cables, made up of the low relaxation and high-strength galvanized steel wires, were arranged. Two kinds of the structural systems of the rigid fixity system of pier, pylon and girder and the floating system were compared from aspects of the temperature action, truck load action and stability coefficients of the completed bridge and eventually, the rigid fixity system that is more advantageous to the structural force conditions of the bridge was chosen. The software MIDAS Civil was

  13. Study on a simple method for bending analysis of composite girders with corrugated steel webs; Hakei koban web wo motsu goseiketa no kan`i mage kaisekiho ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, N.; Yoda, T. [Waseda University, Tokyo (Japan). School of Science and Engineering

    1997-10-15

    An evaluation is being established on composite girders with corrugated steel webs that they are a composite girder having excellent mechanical characteristics. However, structural analysis of these composite girders is not easy even of the one-dimensional analysis. Therefore, a proposal was made on a simple method for bending analysis of a composite girder with corrugated webs having I-section subjected to bending. The result of the analysis using the proposed method was compared with measured values, and the reasonability of the test was investigated including that for the non-linear region. In this analysis, the I-section girder was converted equivalently into a multi-layered beam consisting of cross sections with an equivalent width, and displacement and stress in each layer were approximated linearly by dividing the multi-layered beam into fine layers of `N` number. Formulation was performed by using an ordinary matrix method based on the derived displacement field and stress field. An initial stress method was used for non-linearity analysis of the beams. This analysis was found effective in analyzing a beam subjected to strong effect of shear as in a corrugated steel web composite girder. Among the results of the linearity analyses, the displacement and stress agreed nearly well with the measured values. The non-linearity analysis was performed simply when combined with the initial stress method. 16 refs., 24 figs., 4 tabs.

  14. Cosmetic Foot Surgery: Fashion's Pandora's Box

    Science.gov (United States)

    ... News, Videos & Podcasts » Articles » Text Size Print Bookmark Cosmetic Foot Surgery: Fashion’s Pandora’s Box? Cosmetic Foot Surgery: Fashion’s Pandora’s Box? Foot and Ankle Surgeons Warn ...

  15. Principles of Bridge Reliability

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Nowak, Andrzej S.

    The paper gives a brief introduction to the basic principles of structural reliability theory and its application to bridge engineering. Fundamental concepts like failure probability and reliability index are introduced. Ultimate as well as serviceability limit states for bridges are formulated...

  16. The floating water bridge

    International Nuclear Information System (INIS)

    When high voltage is applied to distilled water filled in two glass beakers which are in contact, a stable water connection forms spontaneously, giving the impression of a floating water bridge. A detailed experimental analysis reveals static and dynamic structures as well as heat and mass transfer through this bridge

  17. The Heuristic Interpretation of Box Plots

    Science.gov (United States)

    Lem, Stephanie; Onghena, Patrick; Verschaffel, Lieven; Van Dooren, Wim

    2013-01-01

    Box plots are frequently used, but are often misinterpreted by students. Especially the area of the box in box plots is often misinterpreted as representing number or proportion of observations, while it actually represents their density. In a first study, reaction time evidence was used to test whether heuristic reasoning underlies this…

  18. Wildlife use of existing culverts and bridges in North Central Pennsylvania

    OpenAIRE

    Brudin, Carl O. III

    2003-01-01

    The Pennsylvania Department of Transportation (PENNDOT) District 3-0 initiated a study in North Central Pennsylvania evaluating existing bridges and culverts for use as underpasses by wildlife. This project was a two-phase study to investigate animal passage through existing drainage box culverts, arch culverts and bridges on existing highway systems. The objective of this study was to (1) determine whether wildlife are using existing structures as passageways based on wildlife sign and remot...

  19. Bridge Assessment and Health Monitoring with Distributed Long-Gauge FBG Sensors

    OpenAIRE

    Chunfeng Wan; Wan Hong; Jianxun Liu; Zhishen Wu; Zhaodong Xu; Shu Li

    2013-01-01

    Most sensors for structural testing and health monitoring are “point” sensors which strongly limit the ability to correct damage detection and structural assessment. In this paper, long-gauge FBG sensor which can sense the whole area within the gauge length is introduced. Bridge assessment and health monitoring with the microstrain distribution acquired by the distributed long-gauge FBG sensor are also studied. Experiments were conducted and application to a real prestressed box bridge was al...

  20. Box-shaped halophilic bacteria.

    OpenAIRE

    Javor, B; Requadt, C; Stoeckenius, W

    1982-01-01

    Three morphologically similar strains of halophilic, box-shaped procaryotes have been isolated from brines collected in the Sinai, Baja California (Mexico), and southern California (United States). Although the isolates in their morphology resemble Walsby's square bacteria, which are a dominant morphological type in the Red Sea and Baja California brines, they are probably not identical to them. The cells show the general characteristics of extreme halophiles and archaebacteria. They contain ...

  1. Broken links and black boxes

    DEFF Research Database (Denmark)

    Sindbæk, Søren Michael

    2013-01-01

    Long-distance communication has emerged as a particular focus for archaeological exploration using network theory, analysis, and modelling. Initial attempts to adapt methods from social network analysis to archaeological data have, however, struggled to produce decisive results. This paper argues...... ruined network from observable distributions and patterns of association in the archaeological record. In formal terms this is not a problem of network analysis, but network synthesis: the classic problem of cracking codes or reconstructing black-box circuits....

  2. Das k-Box-Produkt

    OpenAIRE

    Elser, Stefan

    2011-01-01

    Ziel dieser Doktorarbeit ist es, bekannte und oft verwendete Eigenschaften des Tychonow-Produkts in analoger Form für das k-Box-Produkt zu beweisen, was bisher noch nicht geschehen ist, und die Verbindung zwischen der Infinitären Kombinatorik und der Topologie zu vertiefen. In der Infinitären Kombinatorik, ein Zweig der modernen Mengenlehre, bedient man sich gerne topologischer Begriffe, um einerseits Ergebnisse zu verdeutlichen und um andererseits den sehr abstrakten kombinatorischen Be...

  3. Research on Construction Technology of GFRP-steel Composite Bridge%GFRP-钢组合结构桥梁施工技术研究

    Institute of Scientific and Technical Information of China (English)

    朱坤宁; 万水

    2011-01-01

    纤维增强复合材料(FRP)桥面板是近年来在桥梁工程中应用的一种新型桥面板结构.大广高速6号立交桥为我国第一座GFRP桥面板组合结构公路桥.介绍了GFRP-钢组合结构桥梁的施工技术,包括GFRP拉挤型材的黏结,GFRP桥面板的吊装与黏结和螺栓连接件的安装工艺.解决了GFRP桥面板间的连接问题和GFRP板与承重梁间的连接问题,施工方法满足工程要求.%Fiber reinforced polymer bridge deck is an innovated structural element applied to bridge engineering recently. The No. 6 bridge overpass of Daqing-Guangzhou highway is the first GFRP-steel composite highway bridge in China. Combing with the actual project, main construction processes are introduced including the gluing of GFRP profiles, lifting and bonding of GFRP bridge deck and the installation of bolt connector. The connection problems among GFRP bridge decks are solved, as well as the connection problems between the GFRP deck and the steel girder. The construction method can meet requirements of the project.

  4. Automated analysis of long-term bridge behavior and health using a cyber-enabled wireless monitoring system

    Science.gov (United States)

    O'Connor, Sean M.; Zhang, Yilan; Lynch, Jerome; Ettouney, Mohammed; van der Linden, Gwen

    2014-04-01

    A worthy goal for the structural health monitoring field is the creation of a scalable monitoring system architecture that abstracts many of the system details (e.g., sensors, data) from the structure owner with the aim of providing "actionable" information that aids in their decision making process. While a broad array of sensor technologies have emerged, the ability for sensing systems to generate large amounts of data have far outpaced advances in data management and processing. To reverse this trend, this study explores the creation of a cyber-enabled wireless SHM system for highway bridges. The system is designed from the top down by considering the damage mechanisms of concern to bridge owners and then tailoring the sensing and decision support system around those concerns. The enabling element of the proposed system is a powerful data repository system termed SenStore. SenStore is designed to combine sensor data with bridge meta-data (e.g., geometric configuration, material properties, maintenance history, sensor locations, sensor types, inspection history). A wireless sensor network deployed to a bridge autonomously streams its measurement data to SenStore via a 3G cellular connection for storage. SenStore securely exposes the bridge meta- and sensor data to software clients that can process the data to extract information relevant to the decision making process of the bridge owner. To validate the proposed cyber-enable SHM system, the system is implemented on the Telegraph Road Bridge (Monroe, MI). The Telegraph Road Bridge is a traditional steel girder-concrete deck composite bridge located along a heavily travelled corridor in the Detroit metropolitan area. A permanent wireless sensor network has been installed to measure bridge accelerations, strains and temperatures. System identification and damage detection algorithms are created to automatically mine bridge response data stored in SenStore over an 18-month period. Tools like Gaussian Process (GP

  5. Bridge technology report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. As LANs have proliferated, new technologies and system concepts have come to the fore. One of the key issues is how to interconnect networks. One means of interconnection is to use a 'bridge'. Other competing technologies are repeaters, routers, and gateways. Bridges permit traffic isolation, connect network segments together and operate at the MAC layer. Further, because they operate at the MAC layer, they can handle a variety of protocols such as TCP/IP, SNA, and X.25. This report focuses on the specific technology of bridging two netw

  6. Bridge Management Systems:present and future

    OpenAIRE

    Thoft-Christensen, Palle

    1997-01-01

    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.

  7. 三塔斜拉桥设计参数分析%Analysis of Design Parameters for Three-Pylon Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    杨庸; 雷俊卿

    2016-01-01

    To study the mechanical behavior of the three‐pylon cable‐stayed bridge structure , combined with the real design cases of three‐pylon composite girder cable‐stayed bridge projects , the finite element model of three‐pylon composite girder cable‐stayed bridge was established to car‐ry out parametric study on the effect of the measures taken ,such as to superimpose stay cables , install stay cables between pylons ,improve pylon stiffness and add auxiliary piers ,and the varia‐tion law of their load bearing behaviors is concluded .The results of the calculation demonstrate that the load bearing capacity of the intermediate pylon ,main girder and stay cables can be effec‐tively improved by adding superimposed cables ,stiffening cables between pylons and auxiliary piers to side spans ,and the pier‐top horizontal displacement and the mid‐span deflection of the main girder can also be reduced .T he pier‐top displacement can be reduced by enhancing the stiff‐ness of the intermediate pylon .The increase of the stiffness of side pylons has little influence on the structure .The increase of the height of the intermediate pylon is capable of improving the in‐ternal force of the pylons ,but accelerating the pier‐top displacement .T he results of the calculation can provide reference for the design of configuratiion of three‐pylon composite girder cable‐stayed bridge structure .%为研究三塔斜拉桥结构的力学行为特征,为三塔斜拉桥设计提供参考,结合三塔结合梁斜拉桥工程设计实例,建立三塔结合梁斜拉桥的有限元模型,对斜拉索重叠布置、塔间斜拉索、提高桥塔刚度及采用辅助墩等措施进行参数分析,总结其受力行为的变化规律。计算结果显示:设置重叠索、设置塔间加劲索、边跨设置辅助墩可有效改善中塔、主梁、斜拉索受力,减少塔顶水平位移值及跨中主梁挠度值;提高中塔刚度可以减少塔顶位

  8. Bridging a cultural gap

    Science.gov (United States)

    Leviatan, Talma

    2008-09-01

    There has been a broad wave of change in tertiary calculus courses in the past decade. However, the much-needed change in tertiary pre-calculus programmes—aimed at bridging the gap between high-school mathematics and tertiary mathematics—is happening at a far slower pace. Following a discussion on the nature of the gap and the objectives of a potential bridging programme, this paper aims at demonstrating that the gap can be bridged, by presenting an ongoing modular bridging programme especially designed for the diverse types of student populations in teachers training colleges. We also present here some innovative teaching and assessment methods that were judged essential for the success of these programmes—focusing mainly on the "Questionnaire Based Instruction Method". Finally we suggest directions of follow up and research.

  9. Bridged Race Population Estimates

    Data.gov (United States)

    U.S. Department of Health & Human Services — Population estimates from "bridging" the 31 race categories used in Census 2000, as specified in the 1997 Office of Management and Budget (OMB) race and ethnicity...

  10. 连续弯梁(刚构)桥的统一计算模式%Unified model for continuous curved girder bridges

    Institute of Scientific and Technical Information of China (English)

    许汉铮; 黄平明; 王宏博

    2002-01-01

    对连续弯梁(刚构)桥的支承类型进行了深入分析,将各种支承形式都拟化成两个弹性抗转动支承和一个竖向弹性支承,并通过8自由度曲杆单元模式,形成连续弯梁(刚构)桥的统一计算方法.最后给出一个算例,并用SAP通用程序进行了验证.

  11. Evaluation of frequency spectrum and main oscillation modes of box type multiple cross sections spans

    Directory of Open Access Journals (Sweden)

    Sokolov Oleg Leonidovich

    2014-05-01

    Full Text Available From the viewpoint of mechanics the box span of trestle bridges is non-diaphragm prismatic shell of multiple cross section of average length. Though many problems of static analysis of such structures have been solved, the development of analytical methods of calculating non-diaphragm box type structures on the vibration is an urgent task. The presented method for analysis of free vibration of non-diaphragm spans of box trestle bridges of multiple cross sections is based on the variation theory of prismatic shells of average length by V.Z. Vlasov. In this method the discrete-continuum design scheme, in which the mass of the structure is reduced to its nodal lines, is used. Equations of free vibration are variation equations and represent the work of internal and external forces in the possible displacements. The possible displacements are determined by the static approximation. The order frequency equation, obtained by solving the equation system of free vibration, coincides with the number of the vertical walls of the box span. For a split design scheme span the frequency equation is algebraic, and its components are calculated in analytical formulas. The method is illustrated by free vibrations of non-diaphragm box spans with four cross sections. As a result, the solution frequency spectrum and modes of vibration were defined. The advantage of the presented method of calculation is that the components of the frequency equation are calculated in analytical formulas. This method helps to study free vibration non-diaphragm box spans of multiple cross sections depending on changes in the design parameters. Application of this method will reduce the time and improve the design quality, and also monitor the results of structures analysis prepared with the help of computer complex.

  12. Integral Abutment and Jointless Bridges

    OpenAIRE

    Cristian-Claudiu Comisu

    2005-01-01

    Integral bridges, or integral abutment and jointless bridges, as they are more commonly known in the USA, are constructed without any movement joints between spans or between spans and abutments. Typically these bridges have stub-type abutments supported on piles and continuous bridge deck from one embankment to the other. Foundations are usually designed to be small and flexible to facilitate horizontal movement or rocking of the support. Integrally bridges are simple or multiple span ones t...

  13. Ionization box type radiation detector

    International Nuclear Information System (INIS)

    An ionization box for monitoring radiation rays, a first amplification circuit of a multi-stage amplification circuit employing a MOS type FET as an initial stage amplification device, a second amplification circuit employing a junction type FET as an initial stage amplification device, a first change-over switch for switching ionization current depending on input signals, a second change-over switch for switching output signals, and a signal level discrimination circuit are constituted integrally. When radiation dose rate is low, the ionization current is inputted to the first amplification circuit and outputted as a radiation ray monitor signal and, when the radiation dose rate is increased to higher than a predetermined value, the ionization current is inputted to the second amplification circuit and outputted as a radiation ray monitor signal. That is, monitoring accuracy is high when the ionization current is low since the MOS type FET of high input impedance is used. If the ionization current is higher than a predetermined value, there is no worry that the detection becomes impossible since the junction type FET having less worry of causing characteristic change due to high radiation dose rate is used. Accordingly, ionization box type monitor at a high monitoring reliability can be obtained. (N.H.)

  14. F-box proteins in flowering plants

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In eukaryotes, the ubiquitin-mediated protein degradation pathway has been shown to control several key biological processes such as cell division, development, metabolism and immune response. F-box proteins, as a part of SCF (Skp1-Cullin (or Cdc53)-F-box) complex, functioned by interacting with substrate proteins, leading to their subsequent degradation by the 26S proteasome. To date, several F-box proteins identified in Arabidopsis and Antirrhinum have been shown to play important roles in auxin signal transduction, floral organ formation, flowering and leaf senescence. Arabidopsis genome sequence analysis revealed that it encodes over 1000 predicted F-box proteins accounting for about 5% of total predicted proteins. These results indicate that the ubiquitin-mediated protein degradation involving the F-box proteins is an important mechanism controlling plant gene expression. Here, we review the known F-box proteins and their functionsin flowering plants.

  15. Understanding Recommender Dynamics driving Box Office Revenues

    CERN Document Server

    Yeung, C H; Jin, C -H

    2010-01-01

    We introduce a simple model to investigate the underlying dynamics driving movie box office. Without an explicit reliance on time, the box office of movies evolves naturally by movie-movie competition through reviews listed on a centralized recommender system. A simple mean-field approximation is employed which assumes an average interaction between the competing movies, and describes the interesting box office dynamics. Box office hits are found for movies with quality beyond a critical value, leading to booms in gross box office. Such critical value is dependent on the reviewing behaviors, intention of movie goers for new movies, and the quality of the peer competing movies. Finally we compare our analytical results with simulations and real system and obtain qualitative agreements, suggesting the present model in describing the fundamental dynamics of box office.

  16. Metod of black box and their us

    OpenAIRE

    Novotný, Martin

    2013-01-01

    This thesis on a topic "black-box method and its use" deals with the description of the method of solving problematic tasks as a black box and its use in teaching. Using the theory of systems and cybernetics disciplines, especially cybernetic-pedagogy attempts to describe this method so that it is as efficient as possible and to maximize the benefits for students. Besides, the implementation of selected black box that will be suitable and used for teaching subjects electrotechnics, automatiza...

  17. Evaluation of the earthquake resistant capacity of three-dimensional multi-span rigid frame bridges; Takeikan rittai ramen kyoryo no taishinsei hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Shimamura, K.; Kasabo, H.; Ando, K.; Tanaka, K. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1998-07-01

    The earthquake resistant capacity was evaluated for three-dimensional multi-span rigid frame bridges based on the seismic response analysis results using a finite element method model. For the analyzed bridge model, three-span curved bridge and four-span straight bridge is jointed by the beam border. There are wide-span steel rigid frame piers with underground beams and racket-type piers. Specified seismic acceleration such as occurred at the Hyogo-ken Nanbu Earthquake was used for the analysis condition. According to the analysis model, analysis condition and analysis procedure, analysis results are illustrated for the eigen vibration analysis, effects of time span on the time history response analysis, effects of propagation velocity of seismic waves, elasto-plastic time history response analysis, and static cyclic response analysis. Then, the evaluation results of earthquake resistant capacity are provided for the examinations of stiffener properties, generated strain, plasticity rate, strength of anchors, safety factor against the breakdown, residual displacement of the border model of two sections of girder of piers, and evaluation of the earthquake resistant capacity of the entire bridge. 4 refs., 25 figs., 5 tabs.

  18. 矮墩桥梁的抗震设计与计算%Seismic Design and Calculation of Short Pier Bridge

    Institute of Scientific and Technical Information of China (English)

    宿其连

    2014-01-01

    以3×30m连续梁桥为例,在桥墩高度为5m时,建立该桥的三维有限元模型。桥梁主梁和桥墩通过弹性连接来模拟桥梁支座,考虑土和桩基的相互作用,通过土弹簧来模拟,并在桥梁横向和纵向两个方向输入地震作用。采用反应谱法进行分析。%This is a study on the building of the three-dimensional finiteelement model. It takes the continuous beam bridge which is 3í30m in length and 5m in height as an example. The bridge bearings are supposed to be constructed by elastic connect-ion of the bridge girder and pier. To take the bridge as a whole, the interaction between soil and pile foundation should be put into consideration. Soil spring is used to simulate the model, and the seismic effect is input in horizontal and vertical direction of the bridge. The data are analyzed by response spectrum method.

  19. Improved design of large wind turbine blades of fibre composites (Phase 2) - Summary Report

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Branner, K.; Stang, H.;

    2005-01-01

    The major results of Phase 2 of a project concerning the development of new design methods for wind turbine blades are summarised. Finite element models were used for studying the buckling behaviour of a box girder, tested to failure in Phase 1 of thisproject. The deformation behaviour of a box...... girder section subjected to transverse forces was investigated experimentally and by modelling. Buckling-driven delamination of planar specimens was studied on experimentally and by modelling. A novel approachwas proposed for the determination of mixed mode cohesive laws for large-scale crack bridging...

  20. Repackaging SRS Black Box TRU Waste

    International Nuclear Information System (INIS)

    Historically, large items of TRU Waste, which were too large to be packaged in drums for disposal have been packaged in various sizes of custom made plywood boxes at the Savannah River Site (SRS), for many years. These boxes were subsequently packaged into large steel ''Black Boxes'' for storage at SRS, pending availability of Characterization and Certification capability, to facilitate disposal of larger items of TRU Waste. There are approximately 107 Black Boxes in inventory at SRS, each measuring some 18' x 12' x 7', and weighing up to 45,000 lbs. These Black Boxes have been stored since the early 1980s. The project to repackage this waste into Standard Large Boxes (SLBs), Standard Waste Boxes (SWB) and Ten Drum Overpacks (TDOP), for subsequent characterization and WIPP disposal, commenced in FY04. To date, 10 Black Boxes have been repackaged, resulting in 40 SLB-2's, and 37 B25 overpack boxes, these B25's will be overpacked in SLB-2's prior to shipping to WIPP. This paper will describe experience to date from this project

  1. Interchangeable breech lock for glove boxes

    Energy Technology Data Exchange (ETDEWEB)

    Lemonds, David Preston

    2015-11-24

    A breech lock for a glove box is provided that may be used to transfer one or more items into the glove box. The breech lock can be interchangeably installed in place of a plug, glove, or other device in a port or opening of a glove box. Features are provided to aid the removal of items from the breech lock by a gloved operator. The breech lock can be reused or, if needed, can be replaced with a plug, glove, or other device at the port or opening of the glove box.

  2. Realization of the farad from the dc quantum Hall effect with digitally-assisted impedance bridges

    CERN Document Server

    Callegaro, Luca; Trinchera, Bruno

    2010-01-01

    A new traceability chain for the derivation of the farad from dc quantum Hall effect has been implemented at INRIM. Main components of the chain are two new coaxial transformer bridges: a resistance ratio bridge, and a quadrature bridge, both operating at 1541 Hz. The bridges are energized and controlled with a polyphase direct-digital-synthesizer, which permits to achieve both main and auxiliary equilibria in an automated way; the bridges and do not include any variable inductive divider or variable impedance box. The relative uncertainty in the realization of the farad, at the level of 1000 pF, is estimated to be 64E-9. A first verification of the realization is given by a comparison with the maintained national capacitance standard, where an agreement between measurements within their relative combined uncertainty of 420E-9 is obtained.

  3. Tsunamis: bridging science, engineering and society.

    Science.gov (United States)

    Kânoğlu, U; Titov, V; Bernard, E; Synolakis, C

    2015-10-28

    Tsunamis are high-impact, long-duration disasters that in most cases allow for only minutes of warning before impact. Since the 2004 Boxing Day tsunami, there have been significant advancements in warning methodology, pre-disaster preparedness and basic understanding of related phenomena. Yet, the trail of destruction of the 2011 Japan tsunami, broadcast live to a stunned world audience, underscored the difficulties of implementing advances in applied hazard mitigation. We describe state of the art methodologies, standards for warnings and summarize recent advances in basic understanding, and identify cross-disciplinary challenges. The stage is set to bridge science, engineering and society to help build up coastal resilience and reduce losses. PMID:26392618

  4. Crack mitigation in concrete bridge decks through experimental analysis and computer modeling

    Science.gov (United States)

    Richardson, Douglas M.

    Bridge deck cracking can cause deterioration of bridge decks, leading to a shorter life span and poor performance. Throughout the US, cracking has been identified as a problem, with transverse cracking along the deck at regular spacings being the most prominent type. This problem is usually caused by drying shrinkage within the concrete. The material properties, restraint, and distances without expansion joints all affect the crack pattern within the deck. This study will delve into the reasons that bridge decks crack, the strains that are associated with drying shrinkage, and possible methods for abating its effects. The research is divided into two parts, the first being laboratory experimentation, which was conducted through the use of two 7 ft. x 10 ft. experimental concrete bridge bays. Each bay was instrumented with strain and temperature gages throughout the deck and girders, which collected data for six months. The first deck was poured with a control concrete mix used currently in Illinois. The second deck was poured with a type K expansive concrete, which could battle the effects of shrinkage. For both decks, the results suggest a compressive strain throughout the rebar and along the top surface of the concrete, except for the locations where cracks are found (at these locations the strain slopes upward into tension). The strain in the type K deck, though, was notably less than that in the control deck and the onset of cracking was delayed by three weeks, giving the indication of an improvement over the current mix design. The second portion of the research was focused on using a finite element model to replicate the bridge bay and study the results. Equivalent temperature loading was used to apply the shrinkage loads recorded during the experimental portion of the research. The model was then expanded to encompass a full-scale bridge and in order to provide some insight into shrinkage strain in the real world. The end goal is to help alleviate cracking

  5. Reliability evaluation of axially loaded steel members design criteria in AASHTO LRFD bridge design code

    International Nuclear Information System (INIS)

    Reliability based structural design insures a uniformly designed structure, in terms of safety. By considering an adequate reliability index (or probability of failure) for different parts of a structure, a reasonable balance between cost and safety of the structure can be achieved. In this study, the reliability of steel tension and compression members designed with AASHTO LRFD bridge design specifications (2007) is evaluated. These members are prevalent in different types of truss or arch bridges. Various conditions such as redundancy, ductility and importance of the bridge are taken into account by changing the load modification factor, η. To include the effect of the span length, a variable ratio of dead load to total load is considered. Current load factors in AASHTO LRFD code are accepted due to their verification in a comprehensive study for reliability of girder-type bridges. Furthermore, load and resistance distribution models are chosen based on the latest existing experimental data. The Monte Carlo simulation technique with randomly generated samples is applied in numerical calculations. For tension members, analysis results show relatively high reliability indices in yielding design, while having slightly low reliabilities for the fracture mode. For fracture design of steel tension members, an increase in vehicular dynamic load allowance (IM) from 33% to 75% is suggested to insure a safer behavior. Also, it is shown that the resistance factor for yielding of gross section, φy, can be increased from 0.95 to 1.00 while maintaining enough safety for designed tension members. In addition, obtained reliability curves for steel compression members show a safe behavior of designed compression members with conservative response in some cases. More results and plotted curves are discussed in detail and possible adjustments in code criteria are presented in this paper

  6. Model Equations: "Black Box" Reconstruction

    Science.gov (United States)

    Bezruchko, Boris P.; Smirnov, Dmitry A.

    Black box reconstruction is both the most difficult and the most tempting modelling problem when any prior information about an appropriate model structure is lacking. An intriguing thing is that a model capable of reproducing an observed behaviour or predicting further evolution should be obtained only from an observed time series, i.e. "from nothing" at first sight. Chances for a success are not large. Even more so, a "good" model would become a valuable tool to characterise an object and understand its dynamics. Lack of prior information causes one to utilise universal model structures, e.g. artificial neural networks, radial basis functions and algebraic polynomials are included in the right-hand sides of dynamical model equations. Such models are often multi-dimensional and involve quite many free parameters.

  7. Istanbul Bridge Conference 2014

    CERN Document Server

    Gülkan, Polat; Mahmoud, Khaled

    2016-01-01

      The book includes peer-reviewed contributions selected from presentations given at the Istanbul Bridge Conference 2014, held from August 11 – 13 in Istanbul, Turkey. It reports on the current challenges in bridge engineering faced by professionals around the globe, giving a special emphasis to recently developed techniques, innovations and opportunities. The book covers key topics in the field, including modeling and analysis methods; construction and erection techniques; design for extreme events and condition assessment and structural health monitoring. There is a balanced presentation of theory, research and practice. This book, which provides the readers with a comprehensive and timely reference guide on current practices in bridge engineering, is intended for professionals, academic researchers and students alike.

  8. 粉房湾长江大桥节段模型风洞试验%Wind Tunnel Test for Sectional Models of Fenfangwan Changjiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    王骑; 廖海黎

    2012-01-01

    Fenfangwan Changjiang River Bridge is a semi-floating system cable-stayed bridge with double pylons and double cable planes. To verify the flutter stability of the bridge under the strong wind and the vortex-induced vibration performance under the common wind speed, the dynamic performance of the bridge was calculated and 6 models of the typical sections of the main girder were prepared according to the geometric scale ratio of 1 : 45. 8 for the wind tunnel fest. In the light of the test, the vibration control measure of installing guide vanes on the wind fairing edge trusses of the main girder was proposed. The results of the calculation and test indicate that the structural stiffness of the bridge is great, the vibration frequency is high* the flutter instability and static wind instability will not occur within the range of the test wind speed and the bridge can meet the requirements of the wind resistance design. By way of installing the guide vanes on the wind fairing edge trusses, the vortex-induced resonance of the bridge can be effectively controlled and the resonance can be made to meet the relevant requirements in the codes.%粉房湾长江大桥为双塔双索面半飘浮体系斜拉桥,为检验该桥在强风下的颤振稳定性及在常遇风速下的涡激振动性能,对该桥动力特性进行计算并按照1∶45.8的几何缩尺比制作6个标准主梁节段模型进行风洞试验,针对试验结果提出在主梁风嘴边桁处设置导流板的制振措施.计算和试验结果表明,该桥结构刚度大、振动频率高,在检验风速范围内不会发生颤振失稳和静风失稳,满足抗风设计要求;通过在主梁风嘴边桁处设置导流板,能够实现对桥梁涡激共振的有效控制,使其满足规范要求.

  9. Unification of box shapes in molecular simulations

    NARCIS (Netherlands)

    Bekker, H.

    1997-01-01

    In molecular simulations with periodic boundary conditions the computational box may have five different shapes: triclinic; the hexagonal prism; two types of dodecahedrons; and the truncated octahedron. In this article, we show that every molecular simulation, formulated in one of these boxes, can b

  10. Black-Box Search by Unbiased Variation

    DEFF Research Database (Denmark)

    Lehre, Per Kristian; Witt, Carsten

    2012-01-01

    The complexity theory for black-box algorithms, introduced by Droste, Jansen, and Wegener (Theory Comput. Syst. 39:525–544, 2006), describes common limits on the efficiency of a broad class of randomised search heuristics. There is an obvious trade-off between the generality of the black-box model...

  11. Cosmetic Foot Surgery: Fashion's Pandora's Box

    Science.gov (United States)

    ... Fashion’s Pandora’s Box? A A A | Print | Share Cosmetic Foot Surgery: Fashion’s Pandora’s Box? Foot and ankle ... extreme and imprudent as it may sound, the cosmetic surgery craze isn't just for faces anymore- ...

  12. Modern biotechnology Panacea or new Pandora's box?

    NARCIS (Netherlands)

    Tramper, J.; Yang Zhu, Yang

    2011-01-01

    According to Greek mythology Pandora was sent down to earth upon the orders of Zeus. She was given a mysterious box which she was not allowed to open. However, Pandora was very curious and when she arrived on earth she couldn?t help taking a peek inside the box. She saw that it was filled with gifts

  13. Box Plots in the Australian Curriculum

    Science.gov (United States)

    Watson, Jane M.

    2012-01-01

    This article compares the definition of "box plot" as used in the "Australian Curriculum: Mathematics" with other definitions used in the education community; describes the difficulties students experience when dealing with box plots; and discusses the elaboration that is necessary to enable teachers to develop the knowledge necessary to use them…

  14. 49 CFR 178.515 - Standards for reconstituted wood boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Standards for reconstituted wood boxes. 178.515... wood boxes. (a) The identification code for a reconstituted wood box is 4F. (b) Construction requirements for reconstituted wood boxes are as follows: (1) The walls of boxes must be made of...

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

    Directory of Open Access Journals (Sweden)

    Gao-Xin Wang

    2015-01-01

    Full Text Available 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 remaining static strains and the temperature field shows apparent linear characteristics, which can be mathematically modeled for the description of static performance. Therefore, multivariate linear regression function combined with principal component analysis is introduced to mathematically model the correlation. Furthermore, the residual static strains of mathematical model are adopted as assessment indicator and three kinds of degradation regulations of static performance are obtained after simulation of the residual static strains. Finally, it is concluded that the static performance of Dashengguan Yangtze Bridge was in a good condition during that period.

  16. Building Migratory Bridges

    Science.gov (United States)

    Roy, Michael; Doss, Laurie K.

    2007-01-01

    The Building Migratory Bridges (BOMB) program--a collaboration between the Marvel wood School and Audubon Sharon in Connecticut and Conservation Research Education Action (CR EA), a U.S. not-for-profit in Panama--uses nontropical migratory bird research in the United States and Panama to demonstrate how negative environmental impacts in one…

  17. Quantum Bidding in Bridge

    Science.gov (United States)

    Muhammad, Sadiq; Tavakoli, Armin; Kurant, Maciej; Pawłowski, Marcin; Żukowski, Marek; Bourennane, Mohamed

    2014-04-01

    Quantum methods allow us to reduce communication complexity of some computational tasks, with several separated partners, beyond classical constraints. Nevertheless, experimental demonstrations of this have thus far been limited to some abstract problems, far away from real-life tasks. We show here, and demonstrate experimentally, that the power of reduction of communication complexity can be harnessed to gain an advantage in a famous, immensely popular, card game—bridge. The essence of a winning strategy in bridge is efficient communication between the partners. The rules of the game allow only a specific form of communication, of very low complexity (effectively, one has strong limitations on the number of exchanged bits). Surprisingly, our quantum technique does not violate the existing rules of the game (as there is no increase in information flow). We show that our quantum bridge auction corresponds to a biased nonlocal Clauser-Horne-Shimony-Holt game, which is equivalent to a 2→1 quantum random access code. Thus, our experiment is also a realization of such protocols. However, this correspondence is not complete, which enables the bridge players to have efficient strategies regardless of the quality of their detectors.

  18. Bridge of Light

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Lying gleaming white under a brooding sky,the Lhasa River Railway Bridge forms a gate to Lhasa City.Built as a part of Qinghai-Tibet Railway,on July 1,2011, the highest altitude railway in the world has been in service for five years. Lhasa,Tibet

  19. Bridge over troubled water?

    DEFF Research Database (Denmark)

    Svendsen, Gunnar Lind Haase; Nannestad, Peter; Svendsen, Gert Tinggaard

    2008-01-01

    The problem of integrating non-Western immigrants into Western welfare states is the focus of this paper. To address this issue, we suggest a social capital approach in which we apply the conceptual pair of bridging social capital (BR), which connects an individual to the broader social structure...

  20. Spatial Effect on Railway Trough Girder with Reactive Powder Concrete%铁路活性粉末混凝土槽形梁的空间作用效应

    Institute of Scientific and Technical Information of China (English)

    李志光; 余自若; 王月

    2013-01-01

    The authors carried out three-dimensional finite element analysis on a 32 m railway trough girder which was made of reactive powder concrete.After working out shear lag coefficients under different load conditions,the rule of shear lag was analyzed,and the results indicated that the shear lag effect in this reactive powder concrete trough girder was larger than that of common concrete girder.Further,the spatial effect on transversal and longitudinal bending moments was analyzed,and the study result on the influence lines of transversal bending moments indicated that,due to the spatial effect,any force on any point of the trough girder would cause transversal bending moment which should not be ignored.Finally,the study result on influence lines of longitudinal bending moments showed that,there was spatial effect on equivalent load in reactive powder concrete trough girder; the closer to the girder end the place was,the more obviously the effect became,which also should not be ignored.Therefore,in the design of this kind of railway girder,the spatial effect on the vicinity of girder end should be taken seriously.%对32 m铁路活性粉末混凝土槽形梁进行三维有限元分析,计算出不同工况下的剪力滞系数,并对剪力滞规律进行分析,研究表明该梁的剪力滞效应较普通混凝土梁更加明显;对其横向和纵向弯矩的空间效应进行分析,对横向弯矩影响线的研究表明,受空间作用的影响,梁上任意一点受力均会在某一截面产生不可忽略的横向弯矩;对纵向弯矩影响线的研究表明空间作用对活性粉末混凝土槽形梁换算荷载的影响在越靠近端部影响越明显,且该影响不可忽略,所以在设计该种梁时需要在靠近端部位置充分考虑空间作用的影响.

  1. Revised Rules for Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Jensen, F. M.; Middleton, C.; Blackmore, A.

    This paper is based on research performed for the Highway Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: Concrete Bridges" It contains details of a methodology which can be used to generate Whole Life (WL) reliability profiles....... These WL reliability profiles may be used to establish revised rules for Concrete Bridges....

  2. Improvements relating to glove boxes

    International Nuclear Information System (INIS)

    It is stated that radiation problems with glove boxes can only be partly overcome by adding shielding to their working faces, since about 25% of the working face may be taken up with glove ports at which the only shielding provided is that of the glove. A glove port cover is here described, mountable above the port, comprising a number of flaps of lead-loaded flexible material. The flaps can be pushed aside by hand to permit access to a glove fixed in the port, but overlap to close off the port when the hand is withdrawn. The lead loaded flexible material preferably has a natural or synthetic rubber base. Constructional details are given. Only the flaps need to be lead-loaded, and to facilitate manufacture and handling the surfaces of the cover are preferably lead-free. Three flaps can suffice, but five or six are preferred. For mounting purposes a cover may have beading at its periphery for clamped location in a groove round the glove port. (U.K.)

  3. Multi-mode traffic-induced vibrations in composite ladder-deck bridges under heavy moving vehicles

    Science.gov (United States)

    Camara, A.; Ruiz-Teran, A. M.

    2015-10-01

    Composite (steel-concrete) ladder-decks represent one of the most common solutions in road bridges nowadays. In these structures the Serviceability Limit State (SLS) of vibrations is traditionally ignored or roughly addressed by means of simple static deflection-based approaches, inherently assuming that the vibrations are controlled by the fundamental longitudinal mode. This work demonstrates that a wide range of high-order vibrational modes, involving the transverse flexure of the slab between longitudinal girders, govern the accelerations recorded in the deck and inside the vehicles. In addition, a new methodology for analysing the Vehicle-Bridge Interaction is proposed, including the approaching platforms, the transition slabs, and the bridge joints. The results suggest that the riding comfort for vehicle users is specially affected by direct effects on the wheels, like the road roughness and possible construction misalignments at the bridge joints, as well as low-frequency vibrations coming from the deck in short or slender bridges. The filtering effects resulting from the average of the response in time and in space when calculating the root mean square acceleration are also explored, and new design parameters are provided. In addition, several structural features (such as the depth and spacing of the longitudinal and transverse steel beams, the thickness of the concrete slab, and the stiffness of the cantilever cross beams at the diaphragm sections) have been studied, and a set of new design criteria has been established. It has been demonstrated that the transverse flexibility of the deck (specially influenced by the support conditions and the slab thickness) is critically important for the users' (pedestrians and vehicle passengers) comfort, as it controls the aforementioned high-order vibrational modes which govern the dynamic response.

  4. 安庆长江铁路大桥主墩大型深水基础施工方案与关键技术%Construction Scheme and Key Construction Techniques for Large Deepwater Foundations of Main Piers of Anqing Changjiang River Railway Bridge

    Institute of Scientific and Technical Information of China (English)

    农代培; 季跃华; 徐炳法

    2012-01-01

    宁安铁路安庆长江铁路大桥主桥为双塔多跨连续钢桁梁斜拉桥,该桥3号、4号墩均采用高桩承台基础.为解决桩基汛期施工风险大和3号墩深水无覆盖层斜岩面环境下桩基施工平台搭建难题,经方案比选,3号、4号墩基础采用先围堰(直径56 m)后平台的双壁钢围堰施工方案.施工中采取了以下关键技术:3号墩围堰采用气囊法下河,4号墩围堰采用整体起吊下河;围堰采用无导向船重锚锚碇系统定位;采用活动插板法快速完成了斜岩面围堰底缺口封堵;围堰采取了分区封底施工.%The main bridge of Anqing Changjiang River Railway Bridge on Nanjing-Anqing Railway is a double-pylon and multi-span continuous steel truss girder cable-stayed bridge and the main piers No. 3 and No. 4 of the bridge are supported on the elevated pile cap foundations. To cope with the problems that the construction risk of the pile foundations would be high in the flood period and the setting-up of the working platform would be difficult for the foundation of the Pier No. 3 on the inclined rock surface in deepwater and without overburden, it was determined through comparison that the construction scheme of building the circular double-wall steel boxed cofferdams (each being 56 m in diameter) for the Piers No. 3 and No. 4 first and setting up the platforms late would be adopted. In the process of the construction, the following key techniques were applied, I. E. The cofferdam for the Pier No. 3 was launched to the river by the air bag method and the cofferdam for the Pier No. 4 was integrally lifted down to the river. Both the cofferdams were positioned at the pier sites by the heavy anchor anchorage systems without utilizing the guiding barges. The opening at the bottom of the cofferdam on the inclined rock surface was fast blockaded by the movable inserted steel plate method and the bases of the two cofferdams were sealed by tremie concrete in areas.

  5. [Retention of adhesive bridges].

    Science.gov (United States)

    Raes, F; De Boever, J

    1994-04-01

    Since the development of adhesive bridges in the early seventies, the retention and therefore the durability of these bridges has been tremendously improved. Conditioning of the non-precious metal by silanisation, careful acid etching of the enamel and the use of the appropriate composite resin are of prime importance. Furthermore, the meticulous preparation with enough interproximal embrace, occlusal rests, interocclusal clearance and cingulum stops is equally important. Including more teeth in the design does not necessarily lead to an improved retention. Besides the material and technical aspects, the whole clinical procedure needs much attention. The retention does not depend on one single factor, but on the precision of all the necessary clinical steps and on a well-defined selection of the material. In this way a five-year survival rate of close to 80% can be obtained. PMID:11830965

  6. Nasal Bridge Intramuscular Hemangioma

    OpenAIRE

    Zulkifli Hamir Basah; Irfan Mohamad; Ramiza Ramza Ramli; Maha Khadum Gayadh; Samarendra Singh Mutum

    2015-01-01

    Intramuscular haemangioma (IMH) is a benign mesenchymal tumour. It appears as a deep, nontender mass within the soft tissue, particularly in the extremities. This tumour may not be obvious on clinical examination. Head and neck IMHs represent only 13.5% of the total IMHs. The most common site for a head and neck IMH is the masseter muscle, followed by trapezius, sternocleidomastoid, and very rarely temporalis muscle. We present a patient with left nasal bridge swelling which was excised and h...

  7. BRIDGING SERVICE QUALITY GAPS

    OpenAIRE

    BARKATH UNISSA

    2012-01-01

    Bridging the Service quality gaps is one of the foremost areas of concern for amarketer. Service marketing is inherently different from product or goods marketing.Services are distinctively characterized by their intangible, heterogeneous, inseparableand perishable nature. The importance of the service sector in today's world is a verywidely accepted and renowned idea. “We are already experiencing a service society“services do have some basic characteristics which make them fundamentally diff...

  8. Bridging as Coercive Accommodation

    CERN Document Server

    Bos, J W; Mineur, A M; Bos, Johan; Buitelaar, Paul; Mineur, Anne-Marie

    1995-01-01

    In this paper we discuss the notion of "bridging" in Discourse Representation Theory as a tool to account for discourse referents that have only been established implicitly, through the lexical semantics of other referents. In doing so, we use ideas from Generative Lexicon theory, to introduce antecedents for anaphoric expressions that cannot be "linked" to a proper antecedent, but that do not need to be "accommodated" because they have some connection to the network of discourse referents that is already established.

  9. Nematic liquid crystal bridges

    Science.gov (United States)

    Doss, Susannah; Ellis, Perry; Vallamkondu, Jayalakshmi; Danemiller, Edward; Vernon, Mark; Fernandez-Nieves, Alberto

    We study the effects of confining a nematic liquid crystal between two parallel glass plates with homeotropic boundary conditions for the director at all bounding surfaces. We find that the free surface of the nematic bridge is a surface of constant mean curvature. In addition, by changing the distance between the plates and the contact angle with the glass plates, we transition between loops and hedgehogs that can be either radial or hyperbolic.

  10. Construction Techniques for Main Bridge of Shiwan Bridge in Foshan City%佛山石湾大桥主桥施工技术

    Institute of Scientific and Technical Information of China (English)

    周爱国

    2012-01-01

    The main bridge of the Shiwan Bridge in Foshan City is a three-span continuous ex-tradosed bridge with span arrangement (90. 5 + 150+90. 5 ) m. To avoid the flood period influence and to protect the water environment at the bridge site, the construction of the piles and pile caps of the bridge was carried out on the working platforms formed by the steel pipe piles + Bailey trusses. After the construction of the bored piles was completed, the working platforms were removed and the single-wall steel sheet piles were inserted and driven. At the time thc foundation pits were excavated, the bases of the steel sheet pile cofferdams were sealed in dry condition. The segments No. 0 of thc main girder werc constructed on the embedded brackets, the segments No. 1~ 16 were constructed segment by segment with the form travelers by the cantilever cast-in-situ method and the closure segments were constructed in the sequence of the segments for the side spans first and the segment for the central span late, using the form travelers as the suspension platforms.%佛山石湾大桥主桥为(90.5+150+90.5)m的三跨连续矮塔斜拉桥.为避免受汛期的影响及保护水环境,承台及桩基础施工采取钢管桩+贝雷梁作为水上施工平台,待钻孔桩施工后,再拆除施工平台、插打单壁钢板桩围堰,在基坑开挖时选择干封法进行封底.主梁0号块采用预埋托架施工,1~16号块采用挂篮逐段悬臂现浇施工,合龙段采用挂篮作为吊挂、按先边跨后中跨的顺序进行施工.

  11. Packing a cake into a box

    KAUST Repository

    Skopenkov, Mikhail

    2011-05-01

    Given a triangular cake and a box in the shape of its mirror image, how can the cake be cut into a minimal number of pieces so that it can be put into the box? The cake has icing, so we are not allowed to put it into the box upside down. V. G. Boltyansky asked this question in 1977 and showed that three pieces always suffice. In this paper we provide examples of cakes that cannot be cut into two pieces to be put into the box. This shows that three is the answer to Boltyansky\\'s question. We also give examples of cakes which can be cut into two pieces. © THE MATHEMATICAL ASSOCIATION OF AMERICA.

  12. Spacer for supporting fuel element boxes

    International Nuclear Information System (INIS)

    A spacer plate unit arranged externally on each side and at a predetermined level of a polygonal fuel element box for mutually supporting, with respect to one another, a plurality of the fuel element boxes forming a fuel element bundle, is formed of a first and a second spacer plate part each having the same length and the same width and being constituted of unlike first and second materials, respectively. The first and second spacer plate parts of the several spacer plate units situated at the predetermined level are arranged in an alternating continuous series when viewed in the peripheral direction of the fuel element box, so that any two spacer plate units belonging to face-to-face oriented sides of two adjoining fuel element boxes in the fuel element bundle define interfaces of unlike materials

  13. Mystery Boxes, X Rays, and Radiology.

    Science.gov (United States)

    Thomson, Norman

    2000-01-01

    Indicates the difficulties of teaching concepts beyond light and color and creating memorable learning experiences. Recommends sequential activities using the mystery box approach to explain how scientists and doctors use photon applications. (YDS)

  14. Packing a cake into a box

    CERN Document Server

    Skopenkov, Mikhail

    2010-01-01

    Given a cake in form of a triangle and a box that fits the mirror image of the cake, how to cut the cake into a minimal number of pieces so that it can be put into the box? The cake has an icing, so that we are not allowed to put it into the box upside down. V.G. Boltyansky asked this question in 1977 and showed that three pieces always suffice. In this paper we provide examples of cakes that cannot be cut into two pieces to put into the box. This shows that three is the answer to V.G. Boltyansky's question. Also we give examples of cakes which can be cut into two pieces.

  15. Decommissioning a tritium glove-box facility

    Energy Technology Data Exchange (ETDEWEB)

    Folkers, C.L.; Homann, S.G.; Nicolosi, A.S.; Hanel, S.L.; King, W.C.

    1979-08-08

    A large glove-box facility for handling reactive metal tritides was decommissioned. Major sections of the glove box were decontaminated and disassembled for reuse at another tritium facility. To achieve the desired results, decontamnation required repeated washing, first with organic liquids, then with water and detergents. Worker protection was provided by simple ventilation combined with careful monitoring of the work areas and employees. Several innovative techniques are described.

  16. Decommissioning a tritium glove-box facility

    International Nuclear Information System (INIS)

    A large glove-box facility for handling reactive metal tritides was decommissioned. Major sections of the glove box were decontaminated and disassembled for reuse at another tritium facility. To achieve the desired results, decontamnation required repeated washing, first with organic liquids, then with water and detergents. Worker protection was provided by simple ventilation combined with careful monitoring of the work areas and employees. Several innovative techniques are described

  17. SET Backaction on the Single Electron Box

    OpenAIRE

    Turek, B. A.; Lehnert, K. W.; Clerk, A.; Gunnarsson, D.; Bladh, K.; Delsing, P.; Schoelkopf, R. J.

    2005-01-01

    We report an experimental observation of the backaction of a Single Electron Transistor (SET) measuring the Coulomb staircase of a single electron box. As current flows through the SET, the charge state of the SET island fluctuates. These fluctuations capacitively couple to the box and cause changes in the position, width, and asymmetry of the Coulomb staircase. A sequential tunnelling model accurately recreates these effects, confirming this mechanism of the backaction of an SET. This is a f...

  18. Behavior of Reinforced Concrete Box Beam Strengthened with CFRP U-Wrap Strips Under Torsion

    Directory of Open Access Journals (Sweden)

    Ma Shengqiang

    2016-01-01

    Full Text Available The present study focuses on the torsional strengthening behavior of reinforced concrete (RC box section beams that are widely used in bridges. Four RC box beams were fabricated, and three of them were wrapped by carbon fiber-reinforced polymer (CFRP U-wrap strips with or without longitudinal strips. The different wrapping configuration, cracking angle, failure pattern, and tensile strain of fibers were investigated and discussed accordingly. The experimental results addressed that U-wrap strips strengthening also can upgrade the ultimate torque of beams moderately. In particular, using U-wrap and longitudinal strips to bond the box beams increased the torsional stiffness slightly. The same equation from different codes for calculating RC specimens can accurately predict the ultimate strength of the control beam, but the calculation of the fib model overestimated the torsional strengthening improvement of the wrapped specimens. However, Ghobarah et al. assumed approximately 3000με of the average ultimate fiber strain in calculating the ultimate strength of the wrapped box beams which shows in relatively appropriate agreement with testing results.

  19. Identification of Flutter Derivatives of Bridge Decks in Wind Tunnel Test by Stochastic Subspace Identification

    Directory of Open Access Journals (Sweden)

    T. Janesupasaeree

    2009-01-01

    Full Text Available Problem statement: Flutter derivatives are the essential parameters in the estimations of the flutter critical wind velocity and the responses of long-span cable supported bridges. These derivatives can be experimentally estimated from wind tunnel test results. Generally, wind tunnel test methods can be divided into free decay test and buffeting test. Compared with the free decay method, the buffeting test is simpler but its outputs appear random-like. This makes the flutter derivatives extraction from its outputs more difficult and then a more advanced system identification is required. Most of previous studies have used deterministic system identification techniques, in which buffeting forces and responses are considered as noises. These previous techniques were applicable only to the free decay method. They also confronted some difficulties in extracting flutter derivatives at high wind speeds and under turbulence flow cases where the buffeting responses dominate. Approach: In this study, the covariance-driven stochastic subspace identification technique (SSI-COV was presented to extract the flutter derivatives of bridge decks from the buffeting test results. An advantage of this method is that it considers the buffeting forces and responses as inputs rather than as noises. Numerical simulations and wind tunnel tests of a streamlined thin plate model conducted under smooth flow by the free decay and the buffeting tests were used to validate the applicability of the SSI-COV method. Then, wind tunnel tests of a two-edge girder blunt type of Industrial-Ring-Road Bridge deck (IRR were conducted under smooth and turbulence flow. Results: The identified flutter derivatives of the thin plate model by the SSI-COV technique agree well with those obtained theoretically. The results from the thin plate and the IRR Bridge deck validated the reliability and applicability of the SSI-COV technique to various experimental methods and conditions of wind flow

  20. HYDROGEN AND VOC RETENTION IN WASTE BOXES

    Energy Technology Data Exchange (ETDEWEB)

    PACE ME; MARUSICH RM

    2008-11-21

    The Hanford Waste Management Project Master Documented Safety Analysis (MDSA) (HNF-14741, 2003) identifies derived safety controls to prevent or mitigate the risks of a single-container deflagration during operations requiring moving, venting or opening transuranic (TRU)-waste containers. The issue is whether these safety controls are necessary for operations involving TRU-waste boxes that are being retrieved from burial at the Hanford Site. This paper investigates the potential for a deflagration hazard within these boxes and whether safety controls identified for drum deflagration hazards should be applied to operations involving these boxes. The study evaluates the accumulation of hydrogen and VOCs within the waste box and the transport of these gases and vapors out of the waste box. To perform the analysis, there were numerous and major assumptions made regarding the generation rate and the transport pathway dimensions and their number. Since there is little actual data with regards to these assumptions, analyses of three potential configurations were performed to obtain some indication of the bounds of the issue (the concentration of hydrogen or flammable VOCs within a waste box). A brief description of each of the three cases along with the results of the analysis is summarized.

  1. Vulnerability of bridges to fire

    DEFF Research Database (Denmark)

    Giuliani, Luisa; Crosti, C.; Gentili, F.

    2012-01-01

    Even if recent effort in developing methodology and measures for design structures against fire and explosions has been mostly focused on buildings, bridges can also be very sensitive to those actions, as witnesses by some recent bridge accidents, which caused major economic losses and also...... endangered people safety in few cases. Purpose of this paper is making a focus on the state of the art of the research and current regulations concerning the response of bridges to fire. Several cases of bridge fires are reported and a focus is made on the occurrence and consequence of bridge fires......, considering both the costs deriving by structural damages and by limited serviceability and other indirect societal aspects. Few cases of recent bridge fire are reviewed in detail and structural consequences are highlighted, distinguishing between damages directly induced by fire and damages induced by local...

  2. Investigation on brittle fracture of high bridge pier by Hyogoken-Nanbu earthquake; Hyogoken nanbu jishin ni yori chukokan ramen kyokyaku ni shojita zeisei hakai o gen`in chosa

    Energy Technology Data Exchange (ETDEWEB)

    Eto, O.; Mihara, T. [Kubota Corp., Osaka (Japan); Miki, C. [Tokyo Institute of Technology, Tokyo (Japan). Faculty of Engineering

    1998-04-21

    During the Hyogoken-nanbu earthquake, Ikuta Bridge for railway was not broken but severely damaged. The steel bridge piers were fractured. The Ikuta Bridge was constructed with two steel rigid frames at its ends and two reinforced concrete rigid frames at its center with a three-span 50 m long steel girder in 1967. During the earthquake, the steel pier at the western end was moved in 1 m toward north, and the movable support and pier at the western end were fractured. At the eastern end, the fixed support and the pier were not damaged, but the RC pier of the support base was fractured. To clarify the cause of damages and the fracture mechanism, dynamic response analysis, static elasto-plastic analysis, observations of fracture faces, and material tests were carried out. As a result, it was considered that the brittle fracture of centrifugal cast steel bridge piers of Ikuta Bridge was caused by the horizontal impact exceeding the bearing force for fractures over the piers after the initial fracture of movable support at the western end. From the observations of fracture faces, peeling tests of paints, and hardness tests, it was suggested that the fractures of cast steel piers were initially generated at the yield stress level. 3 refs., 16 figs., 6 tabs.

  3. Experimental study on the effect of fiber reinforced rubber-rolled pin of the bridge restrainer plate system; Gomu dansho pin wo mochiita rakkyo boshi renketsuban no seiteki oyobi doteki oto tokusei ni kansuru jikkenteki kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Sonoda, Y.; Hikosaka, H. [Kyushu Univ., Fukuoka (Japan); Ishikawa, N. [Defence Academy, Yokosuka, Kanagawa (Japan)] Ikoma, N. [Shibata Industrial Co. Ltd., Osaka (Japan)

    1998-07-21

    As for the big earthquake like Hyogo Ken southern Earthquake, accident like collapsing of bridge girder is extremely difficult to prevent by only one bridge restrainer device. However, there exist considerable many spots not having enough space such as urban roads and so forth or the spots where the renewal of the existing restrainer device is difficult and as for these spots, it is thought that improvement of earthquake resistance performance is necessary by using the restrainer system based o the simple reformation of existing bridge restrainer plate system. In this report, under such condition, rolled pin winding the fiber reinforced rubber surrounding the connected pin was proposed as a technique for improving earthquake resistance by easy reformation of bridge restrainer of Spectacle type bridges which has many construction findings. In order to carry out characteristic and quantitative evaluation of the effect of rubber-rolled pin, two stages, o use level and ultimate level, were considered and static behavior and impact load characteristics for each level were studied experimentally, and comparison was made with the conventional steel pin. 13 refs., 19 figs., 6 tabs.

  4. 49 CFR 178.517 - Standards for plastic boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Standards for plastic boxes. 178.517 Section 178... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.517 Standards for plastic boxes. (a) The following are identification codes for plastic boxes: (1) 4H1 for an expanded plastic box; and (2) 4H2 for...

  5. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  6. Effect of an odor eliminator on feline litter box behavior.

    Science.gov (United States)

    Cottam, Nicole; Dodman, Nicholas H

    2007-02-01

    Decreasing litter box odor may be an important treatment component in addressing feline inappropriate elimination. A three-phase study was conducted to determine if the use of Zero Odor litter box spray increases the preference of litter boxes to cats, presumably by its odor-eliminating quality. In the first phase, cats were given a litter box preference test between a litter box sprayed with Zero Odor and one without. In the second phase, the number of occurrences of behaviors indicative of a cat's dissatisfaction with the litter box (scratching at the sides of the box, floor or wall, hesitating when entering the litter box, balancing on the side of the box and eliminating outside of the litter box) was compared before and after the use of Zero Odor. Last, the frequency of eliminations that occurred outside the litter box was measured during a baseline phase and a test phase, in which Zero Odor was sprayed into all litter boxes in the home. Significantly fewer behaviors associated with feline litter box dissatisfaction and fewer undesirable eliminations were observed in phases 2 and 3, respectively. These findings suggest that use of Zero Odor litter box spray appears to decrease litter box odor and increases the attractiveness of litter box to cats. PMID:17049291

  7. 49 CFR 178.514 - Standards for plywood boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Standards for plywood boxes. 178.514 Section 178... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.514 Standards for plywood boxes. (a) The identification code for a plywood box is 4D. (b) Construction requirements for plywood boxes are as follows:...

  8. Monitoring of concrete bridges

    Czech Academy of Sciences Publication Activity Database

    Pirner, Miroš; Urushadze, Shota

    Orlando,Florida: Society for Experimental Mechanics, Inc, 2007 - (Wicks, A.), s. 250-257 ISBN 0-912053-97-6. [IMAC, Conference & Exposition on Structural Dynamics/25./. Orlando (US), 17.02.2007-19.02.2007] R&D Projects: GA MDS(CZ) 1F45D/013/120; GA ČR(CZ) GA103/05/2066 Institutional research plan: CEZ:AV0Z20710524 Keywords : Long-term measurements * Dynamic response * Bridge * Strain gauges * Rain-flow Subject RIV: JM - Building Engineering

  9. Theory of bridge aerodynamics

    CERN Document Server

    Strømmen, Einar

    2006-01-01

    This text book is intended for studies in wind engineering, with focus on the stochastic theory of wind induced dynamic response calculations for slender bridges or other line ?like civil engineering type of structures. It contains the background assumptions and hypothesis as well as the development of the computational theory that is necessary for the prediction of wind induced fluctuating displacements and cross sectional forces. The simple cases of static and quasi-static structural response calculations are for the sake of completeness also included. The text is at an advanced level in the

  10. Nondestructive testing for bridge diagnosis

    International Nuclear Information System (INIS)

    There are many motivations for bridge diagnosis using Nondestructive testing (NDT) to monitor its integrity. The measured frequency and damping on real bridge are compared in one figure as a function of span length and general aspects are explained. These date were measured in every construction of bridges and applied to design new bridges. Ultrasonic testing is also well used for concrete and steel members mainly to detect internal damages or delaminations. Detail analysis on reflected waves gives us more accurate information about the defect. Experimental results are shown as examples in this paper.

  11. Modelling railway bridge asset management

    OpenAIRE

    Le, Bryant Linh Hai

    2014-01-01

    The UK has a long history in the railway industry with a large number of railway assets. Railway bridges form one of the major asset groups with more than 35,000 bridges. The majority of the bridge population are old being constructed over 100 years ago. Many of the bridges were not designed to meet the current network demand. With an expected increasing rate of deterioration due to the increasing traffic loads and intensities, the management authorities are faced with the difficult task of k...

  12. Environmental life cycle assessment comparison between two bridge types: reinforced concrete bridge and steel composite bridge

    DEFF Research Database (Denmark)

    Du, Guangli; Karoumi, Raid

    2013-01-01

    The concept of sustainable construction has attracted an increased attention. Bridge infrastructures and their belonged construction activities consume considerable material and energy, which is responsible for large environmental burdens. However, the environmental assessment of bridges has not...... been integrated into the decision-making process. This paper presents a systematic LCA method for quantifying the environmental impacts for bridges. The comparison study is performed between a reinforced concrete bridge and a steel bridge as an alternative design, with several key maintenance and EOL...... scenarios outlined. LCA study is performed with the ReCiPe methodology with life cycle inventories data from public database. Five selected mid-point level impact categories and the energy consumption are presented. The result shows that the steel bridge has a better environmental performance due to the...

  13. Computer-aided fabrication of bridges; Kyoryo seisaku ni okeru CAD-CAM no genjo to kadai

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, N. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

    1996-08-01

    Described herein is application of the computer-aided CAD/CAM systems to fabrication of bridges from the designs to inspection and production management in the order of production flow. The design works begin with inputting coordinate values for road alignment to determine alignment drawings, coordinates and haunches, and to output the alignment drawings, coordinates, haunches and calculation of haunches and web crest height, and are extended to automatic designs of major girder sections, splices, stiffeners and floor frames, and to preparation of design calculation sheets. As the drawings, although showing bridge characteristics such as completed shapes, are frequently silent on fabricated shapes, the full-size modeling is effected by an automatic program with the additional data regarding welding-induced shrinkage, cambers, joint gaps, allowances for finishing and bore sizes. The CAM systems for fabrication include those for marking, NC marking for cutting, plasma/gas cutters and panel welding robots, which are connected to DNC servers in LAN systems. 6 refs., 14 figs.

  14. Bending analysis of laminated composite box beams

    Energy Technology Data Exchange (ETDEWEB)

    Tripathy, A.K.; Patel, H.J.; Pang, S.S. (Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Mechanical Engineering)

    1994-01-01

    Box beams are widely used in weight reduction structures such as aircraft wings. The use of composite box beams further reduces the weight factor for such structures with the same deflection and stress as that of isotropic box beams. The difference in the behavior of composite box beam with different fiber orientation, number of plies, and number of stringers also provides a wide range of designing parameters to achieve the required performance for a given problem. A bending analysis has been carried out for the study of deflections and stresses for box beams of different material (isotropic and laminated composites), size, and number of stringers subjected to different kinds of loading conditions. A finite element model has been developed based on the strain energy principle, and the results are compared with an available commercial code COSMOS/M.'' Experiments using aluminum and scotchply composite laminates were conducted to verify the results. An optimal design for size and number of stiffeners for a given loading condition has been achieved. Investigations have also been carried out to find the effect of transverse shear on the span-wise normal stress.

  15. Pharmacy Students’ Knowledge of Black Box Warnings

    Science.gov (United States)

    Shireman, Theresa I.; Generali, Joyce; Rigler, Sally; Mayorga, Angela

    2010-01-01

    Objective To evaluate the progression of pharmacy students’ knowledge of black box warnings across 3 years of didactic training, and to determine how they stay current with new warnings. Methods A cross-sectional survey instrument was administered to pharmacy students in their first (P1), second (P2), and third (P3) professional years. The survey assessed student awareness of medications possessing a black box warning and familiarity with the warning content for 20 medications (15 with and 5 without warnings). Results Mean number of correct responses identifying the presence or absence of a black box warning among the 20 medications were 5.8 ± 3.3, 9.6 ± 4.0, and 14.8 ± 2.8 for the P1, P2, and P3 students, respectively. Knowledge of black box warning content was variable. Students were least aware of the warning content for stavudine and enoxaparin. Students were most familiar with the warning content for paroxetine and estrogen. Conclusion Students’ awareness and understanding of black box warnings was proportional to their educational progression, but their knowledge level was inconsistent across drug groups. PMID:20221356

  16. Construction Technique of Dragging Stay Cables with Parallel Steel Wire Strands into Anchorages for the Second Jiujiang Changjiang River Bridge%九江二桥平行钢丝斜拉索牵引入锚施工技术

    Institute of Scientific and Technical Information of China (English)

    吴小斌; 杜俊; 李东辉

    2014-01-01

    The main bridge of the Second Jiujiang Changjiang River Bridge is a two-pylon six-span asymmetrical hybrid girder cable-stayed bridge with a main span of 818 m and with double ca-ble planes .The stay cables are composed of the φ7 mm parallel steel wires ,each having a nominal tensile strength of 1 670 MPa .By the comparative analysis of the dragging construction techniques of dragging carried out by hoisters ,soft dragging ,strong dragging and a combination of the two , it was determined to drag the stay cables via a combined application of the above dragging tech -niques ,taking into consideration of the facts that the stay cables are very heavy and long and the difference between the cable forces in the central span and the side spans are great .According to the actual characteristics of the construction ,the auxiliary facilities for the stay cables installation were prepared ,including lifting portal mounted on pylon tops and the platform used to drag the ca-bles into the anchorages on the girder ,by which the problems of the insufficient hoisting capacity and the difficult installation of the dragging devices were resolved .To improve the efficiency of stay cable installation ,the short cables were installed by the steel strand elongation method ,effec-tively reducing the dragging force in the pressing anchorages in the girder and accelerating the speed of the cable′s entering into the anchorages in the girder .The long cables were dragged into the anchorages by the soft dragging and combined application of the aforementioned methods ,re-solving the difficulty of dragging the long cables into the anchorages in the girder .%九江二桥主桥为主跨818 m 的六跨不对称双塔双索面混合梁斜拉桥,斜拉索采用平行钢丝斜拉索,钢丝直径7 mm ,抗拉强度标准值1670 MPa 。通过对卷扬机牵引、软牵引、硬牵引及软硬组合牵引等牵引施工工艺的对比分析,结合该桥的斜拉索超重超长、中边跨索

  17. I35W collapse, rebuild, and structural health monitoring - challenges associated with structural health monitoring of bridge systems

    International Nuclear Information System (INIS)

    During evening rush hour traffic on August 1, 2007, the major interstate highway bridge carrying I35W over the Mississippi River in Minneapolis catastrophically failed, tragically taking the lives of thirteen people and injuring many more. The steel truss bridge, constructed in 1967, was undergoing deck reconstruction during the collapse, and was estimated to carry more than 140,000 vehicles daily. This tragedy generated great interest in employment of structural health monitoring systems. The I35W St. Anthony Falls Bridge, a post-tensioned concrete box bridge constructed to replace the collapsed steel truss bridge, contains over 500 instruments to monitor the structural behavior. Numerical models of the bridge are being developed and calibrated to the collected data obtained from truck load tests and thermal effects. The data obtained over the first few years of monitoring are being correlated with the calibrated models and used to develop the baseline bridge behavior. This information is being used to develop a system to monitor and interpret the long-term behavior of the bridge. This paper describes the instrumentation, preliminary results from the data and model calibration, the plan for developing long-term monitoring capabilities, and the challenges associated with structural health monitoring of bridge systems. In addition, opportunities and directions for future research required to fully realize the objectives of structural health monitoring are described.

  18. Nearly Seamless Vacuum-Insulated Boxes

    Science.gov (United States)

    Stepanian, Christopher J.; Ou, Danny; Hu, Xiangjun

    2010-01-01

    A design concept, and a fabrication process that would implement the design concept, have been proposed for nearly seamless vacuum-insulated boxes that could be the main structural components of a variety of controlled-temperature containers, including common household refrigerators and insulating containers for shipping foods. In a typical case, a vacuum-insulated box would be shaped like a rectangular parallelepiped conventional refrigerator box having five fully closed sides and a hinged door on the sixth side. Although it is possible to construct the five-closed-side portion of the box as an assembly of five unitary vacuum-insulated panels, it is not desirable to do so because the relatively high thermal conductances of the seams between the panels would contribute significant amounts of heat leakage, relative to the leakage through the panels themselves. In contrast, the proposal would make it possible to reduce heat leakage by constructing the five-closed-side portion of the box plus the stationary portion (if any) of the sixth side as a single, seamless unit; the only remaining seam would be the edge seal around the door. The basic cross-sectional configuration of each side of a vacuum-insulated box according to the proposal would be that of a conventional vacuum-insulated panel: a low-density, porous core material filling a partially evacuated space between face sheets. However, neither the face sheets nor the core would be conventional. The face sheets would be opposite sides of a vacuum bag. The core material would be a flexible polymer-modified silica aerogel of the type described in Silica/Polymer and Silica/Polymer/Fiber Composite Aero - gels (MSC-23736) in this issue of NASA Tech Briefs. As noted in that article, the stiffness of this core material against compression is greater than that of prior aerogels. This is an important advantage because it translates to greater retention of thickness and, hence, of insulation performance when pressure is

  19. Advances in the theory of box integrals

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, David H.; Borwein, J.M.; Crandall, R.E.

    2009-06-25

    Box integrals - expectations <|{rvec r}|{sup s}> or <|{rvec r}-{rvec q}|{sup s}> over the unit n-cube (or n-box) - have over three decades been occasionally given closed forms for isolated n,s. By employing experimental mathematics together with a new, global analytic strategy, we prove that for n {le} 4 dimensions the box integrals are for any integer s hypergeometrically closed in a sense we clarify herein. For n = 5 dimensions, we show that a single unresolved integral we call K{sub 5} stands in the way of such hyperclosure proofs. We supply a compendium of exemplary closed forms that naturally arise algorithmically from this theory.

  20. 临近营业线下承式钢板梁桥滑移施工技术研究%Research on Sliding Construction Technology for Trough Steel Plate Griders Bridge Adjacent to Line in opreation

    Institute of Scientific and Technical Information of China (English)

    王伟良

    2014-01-01

    During Jinshan railway construction, Sliding The existing 32m deck steel plate girder, the distance of 11m. The two track line spacing is 8.5m,Up-going main line center to the existing bridge abutment at 4.2m,it’s difficult to slid construction near the business line. Through the research on construction tech-nology of steel plate girder slip near the business line, determining the reasonable Jack and slip measures, and have achieved good results, that can reference for similar engineering.%金山铁路改建施工中,将下行线上的既有32m 下承式钢板梁进行滑移施工,滑移距离为11m。该处上下行线的线间距8.5m,上行营业线的中心至既有桥台边为4.2m,临近营业线滑移施工难度大。本文通过对临近营业线钢板梁滑移施工技术研究,确定了合理的千斤顶和滑移措施,取得了良好的施工效果,对类似工程有借鉴意义。

  1. Fire test of DOT 7A Boxes

    International Nuclear Information System (INIS)

    The primary objective of conducting the full-scale fire tests of the DOT (Department of Transportation) 7A FRP Boxes was to provide information to assist in quantifying the fire hazard of the storage located at the Radioactive Waste Management Complex (RWMC), and to learn if changing the storage array will decrease the fire risk. Also, the level of fire fighting and fire protection required to maintain the risk at the RWMC within acceptable DOE guidelines was investigated. Two full-scale fire tests were conducted at Southwest Research Institute (SwRI) in June 1978, using the DOE 7A FRP Plywood Storage Containers. The fire tests showed that when subjected to a substantial ignition source, the boxes will propagate fire as long as no fire-suppression measures are taken. Fire will breach the boxes and spread the radioactive contaminated waste if it is not extinguished. As the fire progresses, additional boxes will become involved, and eventually the entire storage array will ignite. It is recommended that the use of DOT 7A Boxes be discontinued and replaced with noncombustible storage containers. In the event this is not practicable, guidance recommendations are presented to minimize the large fire loss potential. It is also recommended that an investigation be conducted into the number of boxes that can be destroyed and still maintain a safe environment for employees and the public. This investigation should include how far radioactive contamination will spread, what cleanup will be required, anticipated exposure of the people within the area, and the public impact of such a fire

  2. 大板梁翼板对接焊缝的超声波检测%Ultrasonic Testing on Butt Weld of Wing Plate of Main Girder

    Institute of Scientific and Technical Information of China (English)

    唐垚; 喻星星

    2015-01-01

    The ultrasonic testing method of the butt weld of the wing plate with a thickness of 140 mm of the main girder in the utility boiler is introduced. The selection of the probe, the determination of the scanning method in the detection process and the method for depicting the DAC curve using the CSK-Ⅳ test block are mainly discussed.%介绍了电站锅炉大板梁140 mm厚翼板对接焊缝的超声波检测方法. 主要论述了检测过程中探头的选取、 扫查方式的确定以及利用CSK-Ⅳ试块制作DAC曲线的方法.

  3. Thermal bridges of modern windows

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Møller, Eva B.; Nielsen, Anker;

    2013-01-01

    With its focus on reduced energy consumption, contemporary housing construction requires a highly insulated and airtight building envelope with as few thermal bridges as possible.Windows must be carefully designed, as thermal bridges can lead to surface condensation or mold growth, even if the wi...

  4. Vulnerability of bridges to fire

    DEFF Research Database (Denmark)

    Giuliani, Luisa; Crosti, C.; Gentili, F.

    2012-01-01

    Even if recent effort in developing methodology and measures for design structures against fire and explosions has been mostly focused on buildings, bridges can also be very sensitive to those actions, as witnesses by some recent bridge accidents, which caused major economic losses and also endan...

  5. Testing of packings for stuffing boxes

    International Nuclear Information System (INIS)

    The stuffing box packings function when they are sealed tight and do not obstruct the movement of the spindle. Characteristic values are necessary to characterise the materials properties of stuffing box packings. Essentially, the definitions of the characteristic values are known and can be calculated in experimental setups. It is absolutely necessary to standardise the characteristic values as well as the testing procedures in order to be able to provide comparable and reproduceable characteristic values. Depending upon the importance of the fittings, it is necessary to guarantee sufficiently exact and reliable assembly for defined operating conditions. (orig.)

  6. Superconductivity in small metal bridges

    International Nuclear Information System (INIS)

    Josephson effects in weaklinks are discussed for low and high frequency regimes using simple perturbation techniques. It is proven that no measurement of the supercurrent dependence upon frequency above the Riedel peak frequency can be made using rf sources whose frequencies are below the Riedel peak. Thus the bulk of work done in the field on the high frequency structure of the Josephson current is shown to be invalid. Metal bridges shorter than a newly defined temperature independent length for superconductors, l/sub PHONON/, are proven to be identical in their Josephson current behavior to tunneling junctions. The BCS gap equation is generalized to include voltage gradient effects on pairs within the bridge. The oscillation frequency for long bridges (l/sub BRIDGE/ greater than l/sub PHONON/) is shown to be limited to less than 10'' Hz. An experimental test of the new voltage dependent gap is made as well as tests of the pair reforming time of bridges

  7. Bridge Coupler for APT

    CERN Document Server

    Greninger, P T; Spalek, G; Greninger, Paul T.; Rodarte, Henry J.

    2000-01-01

    The Coupled Cavity Drift Tube Linac (CCDTL) used in the Accelerator for the Production of Tritium (APT) is fully described elsewhere [1]. The modules are composed of several machined and brazed segments that must account for the accumulation of dimensional tolerances in the build up of the stack. In addition, space requirements dictate that power fed to the accelerator cannot be through the accelerating cavities. As well, we would like to remove a single segment of the accelerator without removing additional segments. These requirements combined with phasing relationships of the design and space limitations have resulted in a different bridge coupling method used in the module comprising 3-gap segments. The coupling method, phasing relationships and other features that enhance the flexibility of the design will be discussed.

  8. Half Bridge Inductive Heater

    Directory of Open Access Journals (Sweden)

    Zoltán GERMÁN-SALLÓ

    2015-12-01

    Full Text Available Induction heating performs contactless, efficient and fast heating of conductive materials, therefore became one of the preferred heating procedure in industrial, domestic and medical applications. During induction heating the high-frequency alternating currents that heat the material are induced by means of electromagnetic induction. The material to be heated is placed inside the time-varying magnetic field generated by applying a highfrequency alternating current to an induction coil. The alternating electromagnetic field induces eddy currents in the workpiece, resulting resistive losses, which then heat the material. This paper describes the design of a power electronic converter circuit for induction heating equipment and presents the obtained results. The realized circuit is a low power half bridge resonant inverter which uses power MOS transistors and adequate driver circuits.

  9. Nanoparticle bridge DNA biosensor

    Science.gov (United States)

    Huang, Hong-Wen

    A new DNA sensing method is demonstrated in which DNA hybridization events lead to the formation of nanoparticle satellites that bridge two electrodes and are detected electrically. The hybridization events are exclusively carried out only on specific locations, the surfaces of C-ssDNA modified 50 nm GNPs. The uniqueness of this work is that only a small number of T-ccDNA molecules (target DNA and three-base-pair-mismatched DNA in 20nM concentrations. Three single-stranded DNA (ssDNA) system is used in our experiment which includes Capture-ssDNA (C-ssDNA), Target-ssDNA (T-ssDNA) and Probe-ssDNA (P-ssDNA). Both C-ssDNA and P-ssDNA are modified by a thiol group and can hybridize with different portions of T-ssDNA. T-ssDNA requires no modification in three ssDNA system, which is beneficial in many applications. C-ssDNA modified 50nm gold nanoparticle (C-50au) and P-ssDNA modified 30nm gold nanoparticle (P-30au) are prepared through the reaction of thiol-gold chemical bonding between thiolated ssDNA and gold nanoparticle (GNP) (C-ssDNA with 50nm GNP, P-ssDNA with 30nm GNP). We controllably place the C-50au only on the SiO2 band surface (˜ 90nm width) between two gold electrodes (source and drain electrodes) by forming positively- and negatively-charged self-assembled monolayers (SAMs) on SiO2 and gold surface, respectively. DNA modified GNP is negatively charged due to ionization of phosphate group on DNA back bone. C-50au therefore is negatively charged and can only be attracted toward SiO2 area (repelled by negatively charged gold electrode surface). The amine group of positively-charged SAMs on SiO2 surface is then passivated by converting to non-polar methyl functional group after C-50au placement. P-30au is first hybridized with T-ssDNA in the solution phase (T-P- 30au formed) and is introduced into DNA detection device in which C-50au are immobilized on ˜90nm width SiO2 band (between two gold electrodes). The passivation step ensures every TP-30au are attached

  10. Cereal Box Design: An Interdisciplinary Graphics Activity

    Science.gov (United States)

    Fitzgerald, Mike; Tsosie, Teri

    2012-01-01

    The cereal box design activity is intriguing both for its simplicity and the resourcefulness that it can generate in young people. Also, it lends itself to a variety of curriculums. It covers both consumerism and Design for the Environment (DfE) concepts broadly and in depth. The activity introduces a wide range of topics. They include graphic…

  11. Study of WATCH GRB error boxes

    DEFF Research Database (Denmark)

    Gorosabel, J.; Castro-Tirado, A. J.; Lund, Niels;

    1995-01-01

    We have studied the first WATCH GRB Catalogue ofγ-ray Bursts in order to find correlations between WATCH GRB error boxes and a great variety of celestial objects present in 33 different catalogues. No particular class of objects has been found to be significantly correlated with the WATCH GRBs....

  12. Black hole formation in a box

    International Nuclear Information System (INIS)

    Evidence is presented for Hawking's viewpoint that in an insulated box in thermal equilibrium, black holes should form and evaporate in a statistically time-symmetric way. In particular, it is shown that if a black hole can evaporate adiabatically, it is much more likely to form adiabatically than by Jeans instability. (author)

  13. Safety evaluation for packaging CPC metal boxes

    International Nuclear Information System (INIS)

    This Safety Evaluation for Packaging (SEP) provides authorization for the use of Container Products Corporation (CPC) metal boxes, as described in this document, for the interarea shipment of radioactive contaminated equipment and debris for storage in the Central Waste Complex (CWC) or T Plant located in the 200 West Area. Authorization is granted until November 30, 1995. The CPC boxes included in this SEP were originally procured as US Department of Transportation (DOT) Specification 7A Type A boxes. A review of the documentation provided by the manufacturer revealed the documentation did not adequately demonstrate compliance to the 4 ft drop test requirement of 49 CFR 173.465(c). Preparation of a SEP is necessary to document the equivalent safety of the onsite shipment in lieu of meeting DOT packaging requirements until adequate documentation is received. The equivalent safety of the shipment is based on the fact that the radioactive contents consist of contaminated equipment and debris which are not dispersible. Each piece is wrapped in two layers of no less than 4 mil plastic prior to being placed in the box which has an additional 10 mil liner. Pointed objects and sharp edges are padded to prevent puncture of the plastic liner and wrapping

  14. Choreographies with Secure Boxes and Compromised Principals

    DEFF Research Database (Denmark)

    Carbone, Marco; Guttman, Joshua

      We equip choreography-level session descriptions with a simple abstraction of a security infrastruc- ture. Message components may be enclosed within (possibly nested) ”boxes” annotated with the intended source and destination of those components. The boxes are to be implemented with cryp...

  15. RELIABILITY BASED DESIGN OF A GEAR BOX

    Directory of Open Access Journals (Sweden)

    D.MADHUSEKHAR

    2014-08-01

    Full Text Available Reliability is the probability that a system, component or device will perform without failure for a specified period of time under specified operating conditions. The concept of reliability is of great importance in the design of various machine members. Conventional engineering design uses a deterministic approach. It disregards the fact that the material properties, the dimensions of the components and the externally applied loads are statistical in nature. In conventional design this uncertainties are covered with a factor of safety, which is not always successful. The growing trend towards reducing uncertainty and increasing reliability is to use the probabilistic approach. In the present work a three shaft four speed gear box and six speed gear box are designed using reliability principles. For the specified reliability of the system (Gear box, component reliability (Gear pair is calculated by considering the system as a series system. Design is considered to be safe and adequate if the probability of failure of gear box is less than or equal to a specified quantity in each of the two failure modes. . All the parameters affecting the design are considered as random variables and all the random variables are assumed to follow normal distribution. A computer program in C++ is developed to calculate the face widths in bending and surface failure modes. The larger one out of the two values is considered. By changing the variations in the design parameters, variations in the face widths are studied.

  16. Nondestructive assay of boxed radioactive waste

    International Nuclear Information System (INIS)

    This paper describes the problems related to the nondestructive assay (NDA) of boxed radioactive waste at the Hanford Site and how Westinghouse Hanford company (WHC) is solving the problems. The waste form and radionuclide content are described. The characteristics of the combined neutron and gamma-based measurement system are described

  17. A white box perspective on behavioural adaptation

    DEFF Research Database (Denmark)

    Bruni, Roberto; Corradini, Andrea; Gadducci, Fabio; Lluch Lafuente, Alberto; Vandin, Andrea

    We present a white-box conceptual framework for adaptation developed in the context of the EU Project ASCENS coordinated by Martin Wirsing. We called it CoDA, for Control Data Adaptation, since it is based on the notion of control data. CoDA promotes a neat separation between application and...

  18. PVC posting bags for glove boxes

    International Nuclear Information System (INIS)

    This specification covers the materials, measurements and manufacture of unpigmented PVC posting bags for use on glove boxes, together with methods of testing the materials. These bags are used in the handling of radioactive and toxic materials of a hazardous nature and therefore must be of the highest standard of mechanical strength, leak tightness and general finish. (author)

  19. Liquid-Bridge Breaking Limits

    Science.gov (United States)

    Macner, Ashley; Steen, Paul

    2011-11-01

    Wet adhesion by liquid bridges in large arrays shows promise for use in lightweight, controllable on-demand devices. Applications include grab/release of wafer substrates, transport of micron-sized tiles for use in 3D printing and micro-dosing of personalized pharmaceutical drugs. By wetting and spreading, a drop can form a bridge and thereby ``grab'' a nearby solid substrate. By volume decrease or extension, the bridge can break. The breaking limit corresponds to bridge instability which can be predicted, knowing the static mechanical response of the bridge. Mechanical behaviors include force-volume (FV), pressure-volume (pV) and force-length (FL) responses. Instability crucially depends on the mode of failure - failure under constant-force or constant length are typical cases. We study single bridge equilibria for their breaking limits. FV diagrams for the pin-pin equal and pin-pin unequal radii boundary conditions for different bridge heights are measured in the laboratory. The FL response in the case of pin-pin equal radii is also measured. Results are compared to predictions of static theory. Static results are then used to compare to dynamical sequences where volume is driven quasistatically by syringe or an electro-osmotic pump. As the breaking limit is approached, the shape deformation accelerates leading to non-equilibrium shapes not captured by the static analysis.

  20. Bridge Creek IMW database - Bridge Creek Restoration and Monitoring Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The incised and degraded habitat of Bridge Creek is thought to be limiting a population of ESA-listed steelhead (Oncorhynchus mykiss). A logical restoration...