Development of Live Load Distribution Factor Equation for Girder Bridges

Author(s):  
Nakin Suksawang ◽  
Hani H. Nassif
Author(s):  
Jason L. Millam ◽  
Zhongguo (John) Ma

The live load distribution factor equations provided by AASHTO load and resistance factor design specifications for the decked precast, prestressed concrete (DPPC) girder bridge system do not differentiate between a single-lane or a multilane loaded condition. This practice results in a single-lane load rating penalty for DPPC girder bridges. This paper determines distribution factor equations that accurately predict the distribution factor of the DPPC girder bridge system when it is subjected only to single-lane loading. Eight DPPC girder bridges were instrumented. Each bridge was loaded with a single load vehicle to simulate the single-lane loaded condition. The experimental data were used to calibrate grillage models of the DPPC girder bridge system. The calibrated grillage models were used to conduct a parametric study of the DPPC girder bridge system subjected to a single-lane loaded condition. Four new equations that describe the single-lane loaded distribution factor for both shear and moment forces of these bridges are developed in this paper.


2013 ◽  
Vol 284-287 ◽  
pp. 1441-1445
Author(s):  
Doo Yong Cho ◽  
Sun Kyu Park ◽  
Woo Seok Kim

This paper presents the live load distribution in straight prestressed concrete (PSC) girder bridges with curved deck slab utilizing finite element analyses. Numerical modeling methodology was established and calibrated based on field testing results. A parametric study of 73 cases with varying 6 critical parameters was used to determine a trend over each parameter. Through live load girder distribution factor (GDF) comparisons between the AASHTO LRFD, AASHTO Standard factors and finite element analyses results, both AASHTO live load distribution predicted conservatively in most bridges considered in the parametric study. However, in the bridges with curved slab, GDF was underestimated due to curvature influences. This study proposes a new live load distribution formula to predict rational and conservative live load distribution in PSC girder bridges with curved slab for a preliminary design purpose. The proposed live load distribution provides better live load analysis for the PSC girder bridge with curved slab and ensures the GDF is not underestimated.


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

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