Robustness and redundancy finite element analysis of composite deck bridges

Resumo

Structural robustness is a topic that still lacks consensus in both the literature and international standards such as AASHTO, ASCE, and Eurocodes. These standards do not provide clear guidelines for the application and validation of robustness and redundancy concepts in structures. Considering the need to prevent disproportionate or progressive collapse in bridges and viaducts, the impact of these concepts on structural safety must be studied and included in the design phase. This paper proposes a finite element model of the deck of a multi-girder composite bridge composed of three simply supported I-beam girders with full-web sections. The analysis, based on the conventional criteria of the AASHTO LRFD Bridge Design Specifications (2020) and assuming elastic-linear behavior, introduces a discontinuity in the girder mesh to simulate a fracture in the mid-span region. Based on this premise, the study evaluates the redistribution of forces, the performance of the structural elements under the new internal demands, and the maximum vertical displacement of the girders under critical mobile load conditions. The results are compared with theoretical definitions of robustness and redundancy, contributing to the enhancement of analytical methods in structural engineering.