Experimental and numerical investigation of modular steel bridges

This thesis presents a comprehensive investigation into the structural performance of modular bridges through full-scale experimental testing and advanced finite element modeling. The experimental program included full-scale testing of two types of truss panels commonly used in modular bridge construction under ultimate load conditions. It also involved testing a 45-meter single-story double-truss bridge under failure loads, a reinforced version of the same bridge under both service and ultimate conditions, and a working load test on a double-story bridge. The tested bridges and specimens were instrumented with LVDTs and strain gauges to monitor displacements and internal forces. Axial capacities of critical members were compared with nominal values specified in AASHTO and CHBDC design codes. Based on the experimental data, detailed three-dimensional finite element models were developed and validated. The models employed both beam-column and shell elements to explore different simulation approaches. Parametric studies were conducted to assess the influence of member end conditions—pinned versus rigid—on buckling behavior and global capacity. The validated models were then used to compare various bridge configurations, including single-story bridges with quadruple truss lines and double-story bridges with double truss lines, under different lane arrangements. The results showed that shell element models more accurately captured the interaction between material and stability failures. Eigenvalue analysis revealed discrepancies in buckling load predictions between modeling approaches and emphasized the need to consider realistic member end conditions. Correspondingly, an adjustment factor (K) is proposed for the AASHTO-LRFD equation to better reflect the effective length of members. Reinforcing the top and bottom chords increased the bridge’s ultimate capacity by 90% and doubled its stiffness. The strain measurements also indicated a significant role of the deck in load distribution, evidenced by differences between top and bottom chord responses. Finally, the study demonstrated that double-story bridges with two truss lines achieved higher load capacity and stiffness than single-story bridges with quadruple trusses, while double-lane bridges exhibited greater out-of-plane deformation, influencing their structural performance.

Name thesis:degree_name

Ph D

Discipline thesis:degree_discipline

Civil and Environmental Engineering

Grantor dc:publisher

The University of Western Ontario

Year dc:date.issued

2025

Author dc:creator

• Embaby, Mohamed

Advisor dc:contributor.advisor

• El Naggar, M. Hesham

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/20.500.14721/38418

OAI identifier oai:identifier

oai:uwo.scholaris.ca:20.500.14721/38418