Finite Element Analysis of Shear Lag Effect in Long-Span Single-Box Continuous Rigid Bridges

TL;DR

This paper develops a detailed finite element model of long-span continuous rigid bridges to analyze shear lag effects, validating it with experimental data and exploring how geometry influences stress distribution.

Contribution

It introduces a comprehensive FE modeling approach that captures complex geometry and nonlinear effects, improving prediction accuracy over traditional methods.

Findings

Wider box girders increase shear lag effects.

Larger spans significantly amplify shear lag.

Model validation shows close match with experimental data.

Abstract

As the span and width of continuous rigid bridges increase, the complexity of the spatial forces acting on these structures also grows, challenging traditional design methods. Primary beam theory often fails to accurately predict the stresses in the bridge girder, leading to potential overestimation of the ultimate capacity of these bridges. This study addresses this gap by developing a detailed finite element (FE) model of a continuous rigid bridge using ABAQUS, which accounts for the complex 3D geometry, construction procedures, and nonlinear material interactions. A loading test on a 210-meter continuous rigid bridge is performed to validate the model, with the measured strain and deflection data closely matching the FE simulation results. The study also examines stress distributions under constant and live loads, as well as the shear lag coefficients of the main girder. Through parametric analysis, we explore the effects of varying the width-to-span and height-to-width ratios. The results reveal that both a wider box girder and a larger span significantly amplify the shear lag effect in the bridge girder. The findings enhance the understanding of stress distribution in large-scale rigid bridges and provide critical insights for more accurate design and as-sessment of such structures.