Redundancy of Simple Span and Two-Span Welded Steel Two-Girder Bridges

摘要

To minimize the consequences of fracture of steel girder bridges AASHTO requires that reduced allowable fatigue stress ranges be used for nonredundant load path structures. Two-girder bridges are classified as nonredundant by AASHTO. The purpose of the investigation is to study the behavior of three real two-girder bridge spans, determine if redundant load paths exist, and if so, suggest design guidelines and procedures for ensuring redundancy of these two-girder study bridges. Elastic-plastic analyses of the two-girder study bridges were conducted. Design procedures and guidelines were developed and used to redesign the study bridges to not only ensure redundancy but also to ensure after fracture serviceability of the study bridges. The results of the investigation suggest application of these design procedures and guidelines to other types and configurations of two-girder bridges as well as to multi-girder steel bridges.