Study on Spatial Effect of Wide Box Girders under Unbalance Loading

2013 ◽  
Vol 438-439 ◽  
pp. 1093-1097
Author(s):  
Ke Chen ◽  
Lei Wang

Prestressed concrete continuous wide box girder bridge is widely used in urban bridges, because of its large width-span ratio, spatial effects from unbalance load cannot be ignored. When the bridge was analyzed by beam element system, the increased coefficient of unbalance loading is used to simplified space problem into plane problem. Spatial effect of wide box girder under unbalance loading is calculated by solid finite element method, and used in a project example in Hangzhou. Comparing analysis results of solid finite element with other simplified methods, it shows that the solid element method is more applicable and accurate. This method and results offer reference for similar bridge design calculation.

Author(s):  
V. Verma ◽  
K. Nallasivam

Purpose: The primary objective of the current study is to numerically model the steel thin-walled curved box-girder bridge and to examine its various response parameters subjected to Indian Railway loading. Design/methodology/approach: The analysis is conducted by adopting a one dimensional curved thin-walled box-beam finite beam element based on finite element methodology. The scope of the work includes a computationally efficient, three-noded, one-dimensional representation of a thin-walled box-girder bridge, which is especially desirable for its preliminary analysis and design phase, as well as a study of the static characteristics of a steel curved bridge, which is critical for interpreting its dynamic response. Findings: The analytical results computed using finite element based MATLAB coding are presented in the form of various stress resultants under the effect of various combinations of Indian Railway loads. Additionally, the variation in different response parameters due to changes in radius and span length has also been investigated. Research limitations/implications: The research is restricted to the initial design and analysis phase of box-girder bridge, where the wall thickness is small as compared to the cross-section dimensions. The current approach can be extended to future research using a different method, such as Extended finite element technique on curved bridges by varying boundary conditions and number of elements. Originality/value: The validation of the adopted finite element approach is done by solving a numerical problem, which is in excellent agreement with the previous research findings. Also, previous studies had aimed at thin-walled box girders that had been exposed to point loading, uniformly distributed loading, or highway truck loading, but no research had been done on railway loading. Moreover, no previous research had performed the static analysis on thin-walled box-girders with six different response parameters, as the current study has. Engineers will benefit greatly from the research as it will help them predict the static behaviour of the curved thin-walled girder bridge, as well as assess their free vibration and dynamic response analysis.


2011 ◽  
Vol 368-373 ◽  
pp. 705-709
Author(s):  
Ping Hu ◽  
Dong Qi Zhao ◽  
Hui Li ◽  
Gui Feng Song ◽  
Yi Jun Tang

Base the shortcomings of pre-simple-supported post-continuous girder bridge construction, a new beam-bridge convert structure system is proposed, that is a kind of structure form of prestressed concrete hollow multi-ribbed composite box girders, the calculation method of two phase and noting are put forward. the kind of Cast-in-place assembly structure is light self-weight, force structure reasonable, easy construction, overall good and overall cost low.


2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Shi-Jun Zhou

Most of the previous researches conducted on shear lag of box girders were only concerned about simple types of structures, such as simply supported and cantilever beams. The structural systems concerned in these previous researches were considered as determined and unchangeable. In this paper, a finite element method considering shear lag and creep of concrete was presented to analyze the effect of dynamic construction process on shear lag in different types of concrete box-girder bridges. The shear lag effect of the three types of a two-span continuous concrete beam classified by construction methods was analyzed in detail according to construction process. Also, a three-span prestressed concrete box-girder bridge was analyzed according to the actual construction process. The shear lag coefficients and stresses on cross sections along the beam including shear lag were obtained. The different construction methods, the changes of structural system with the construction process, the changes of loading and boundary conditions with the construction process and time, the prestressing, and creep were all imitated in the calculations. From comparisons between the results for beams using different construction methods, useful conclusions were made.


2021 ◽  
Author(s):  
Waqar Khan

Bridges built with adjacent precast, prestressed concrete box-girders are a popular and economical solution for short-span bridges because they can be constructed rapidly. The top flanges of the precast box girders form the bridge deck surface. A shear key is introduced between the adjacent boxes over the depth of the top flange (i.e. 225 mm thick as the thickness of the box's top flange). Canadian Highway Bridge Design Code, CHBDC specifies empirical equations for the moment and shear distribution factors for selected bridge configurations but not for adjacent precast concrete box-girder bridge type. In this study, a parametric study was conducted, using the 3D finite-element modeling, and a set of simplified equations for the moment, shear and deflection distribution factors for the studied bridge configuration was developed.


2015 ◽  
Vol 777 ◽  
pp. 34-37
Author(s):  
Hong Jiang Li

For a long-span prestressed concrete box-girder bridge erected by the double-cantilever segmental method, concrete of segmental joints and concrete in their nearby area may be different from integrally-cast concrete in structural performances. For example, the stiffness of segmental joints could be weakened significantly. To reveal influences of weakening in the stiffness of segmental joints on the deflection at mid-span of box girder, a typical continuous rigid frame bridge in China was taken as the analysis example, and its finite element models were established. In these models, weakening joints were simulated. After the validity of finite element models were warranted, the deflection in the completed construction stage and the long-term deflection in the running period of box girder were calculated, and then the variation of these deflections with the stiffness reduction in all segmental joints was described. Results showed that, compared with the shearing stiffness reduction in segmental joints, the bending stiffness reduction played more significant role in affecting the deflection of box girder. When the weakening times of joint stiffness arrived at 100, deflection values of the box girder increased significantly. However, in the practical engineering, the determination of stiffness reduction in segmental joints according by their damages, and the incorporation of weakening segmental joints into the bearing capacity assessment for existing box girders were all worth further study.


2013 ◽  
Vol 838-841 ◽  
pp. 1014-1017
Author(s):  
Fan Guo ◽  
Yong Qing Yang ◽  
Sheng Qian Huang

Through the checking comparison of example bridge, to analysis the major causes of the cracking and too much deflection for prestressed concrete continuous box girder bridge. Calculated weak position and the current presence of cracks in the bridge position basically consistent, so cracks mainly caused by the prestress loss, concrete creep and the temperature effect, the structure stiffness weakened after cracking, then the actual mid-span deflection is greater than the calculated values bound. Therefore, the cracking and too much deflection appear simultaneous and mutual promote. The view that by improving the mechanical behavior of box girders, design parameters optimization, just the fundamental solution to cracking and too much deflection, also, several key issues need study to be addressed.


2011 ◽  
Vol 422 ◽  
pp. 693-696
Author(s):  
Yan Weng ◽  
Mei Cen ◽  
Ya Guang Xu

A simple box girder bridge with spans 25m is being constructed on the No.2 road of a project of PanZhiHua Steel. A Bailey trussed girder is constructed under the bridge to assist its construction. The paper makes spatial finite element analysis about the Bailey trussed girder. Firstly, the spatial finite element model is built. Then the force, stress and displacement of the girder under six box girders’ self weigh and the construction load are analyzed in detail. Lastly, the construction scheme is optimized. After optimization, all indexes of Bailey trussed girder can meet code requirement.


2021 ◽  
Author(s):  
Waqar Khan

Bridges built with adjacent precast, prestressed concrete box-girders are a popular and economical solution for short-span bridges because they can be constructed rapidly. The top flanges of the precast box girders form the bridge deck surface. A shear key is introduced between the adjacent boxes over the depth of the top flange (i.e. 225 mm thick as the thickness of the box's top flange). Canadian Highway Bridge Design Code, CHBDC specifies empirical equations for the moment and shear distribution factors for selected bridge configurations but not for adjacent precast concrete box-girder bridge type. In this study, a parametric study was conducted, using the 3D finite-element modeling, and a set of simplified equations for the moment, shear and deflection distribution factors for the studied bridge configuration was developed.


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