Effect of intermediate diaphragm on lateral load distribution factor of multicell box-girder bridges

2014 ◽  
Vol 18 (7) ◽  
pp. 2128-2137 ◽  
Author(s):  
Iman Mohseni ◽  
Abdul Khalim Abdul Rashid ◽  
Junsuk Kang
2019 ◽  
Vol 22 (8) ◽  
pp. 1965-1976
Author(s):  
Zhong Ma ◽  
Minjuan He ◽  
Renle Ma ◽  
Zheng Li ◽  
Linlin Zhang

A cyclic loading experiment involving a timber-steel hybrid structure consisting of a steel frame and a novel light timber-steel diaphragm is presented to quantify the flexibility of the diaphragm and its ability to distribute lateral loads in the elastic-plastic phase of the structure. A lateral load-distribution factor was proposed, and its relationship to the ratio of the stiffness of the diaphragm to that of the lateral load-resisting elements was investigated. The diaphragm was classified based on these variables. The results indicated that the failure modes of the structure were associated with the forms of damage experienced by the lateral load-resisting elements, whereas little damage was observed for the diaphragm. The diaphragm exhibited the ability to continuously adjust the distribution of lateral loads to each lateral load-resisting element; accordingly, each lateral load-resisting element had approximately the same shear force, the same lateral stiffness, and the same lateral displacement during the loading process. As the lateral displacement increased, the stiffness ratio and load-distribution factor both gradually increased, and the diaphragm correspondingly changed from semi-rigid to rigid. At times, as the lateral displacement increased, the diaphragm rapidly became rigid, and it was unnecessarily rigid during the initial loading phase when the in-plane stiffness reached a certain threshold.


2005 ◽  
Vol 10 (3) ◽  
pp. 281-290 ◽  
Author(s):  
Hailing Zhang ◽  
Dongzhou Huang ◽  
Ton-Lo Wang

Author(s):  
Hyo-Gyoung Kwak ◽  
Joungrae Kim

Load distribution factor at concrete girder bridges and steel girder bridges are analyzed with finite element method to see effect of span length and cross beam to load distribution factor. Span lengths of analyzed bridge models are 30m, 40m, 50m and 60m. The number of intermediate cross beam is increased from one to until distance between cross beams becomes 5m. The finite element analysis results show that concrete girder and steel girder can use same load distribution factor and span length doesn’t affect to load distribution factor. Even though load distribution factor in interior girders is not influenced by cross beam, in exterior girders it is influenced by cross beam. Effect of cross beam in exterior girder is influenced by the number of lanes and distance from exterior girder to curb. Since design code introduces conservative load distribution factor, economically improved load distribution factor is proposed. The proposed load distribution factor includes cross beam effect with the number of lanes and distance from exterior girder to curb. The proposed equation is compared with AASHTO code and grillage method which is well-known method to calculate load distribution. The comparison results showed that the proposed equation is more efficient and useful than AASHTO and safer than the grillage method.


2021 ◽  
Author(s):  
Siham Kadhim Jawad

Composite box-girder bridges are recently used in modern highway urban system because of their profitable and structural aptitude advantages. North Americans Codes of Practice specify empirical equations for girder moment and shear forces in such bridges in the form of live load distribution factors. These factors were proven to be conservative in some cases and underestimate the response in other cases. Therefore, an extensive parametric study, using the finite-element modeling, was conducted to examine the key parameters that influence the load distribution factors of such bridges. A total of 276 prototype bridges were analyzed to evaluate girder bending moment, shear force and deflection distribution factors for simply-supported composite multiple box-girder bridges when subjected to CHBDC truck loading. Design parameters considered in this study were bridges span length, numbers of design lanes, number of box girders and girder spacing. Based on the data generated from parametric study, sets of simple empirical expressions were developed for bending moment; shear force and deflection distribution factors for such bridges. A correlation between the finite-element results with CHBDC and AASHTO-LRFD empirical expressions showed the former are more reliable in structural design of composite box-girder bridges.


2005 ◽  
Vol 9 (4) ◽  
pp. 313-319 ◽  
Author(s):  
Wonseok Chung ◽  
Kitjapat Phuvoravan ◽  
Judy Liu ◽  
Elisa D. Sotelino

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