TxDOT Research Library - TxDOT Research Project

Show:

Fracture Critical Steel Twin Tub Girder Bridges

What Was the Need?

Twin steel tub girder bridges are an aesthetically pleasing structural option, offering long span solutions in tight radii direct connectors. However, these bridges require a routine two-year inspection frequency, as well as a thorough hands-on inspection, because of their fracture critical designation. The heightened inspection requirements for fracture-critical bridges come at a significant cost to the Texas Department of Transportation (TxDOT). Recent research has shown that tangent, or nearly tangent, twin steel tub girder sections can redistribute load to the intact girder after fracture of one of the girder bottom flanges. Additional research is required to develop recommendations for practical analysis of typical twin steel tub span configurations with the degree of curvature common to twin steel tub direct connectors

Project Summary

A key objective of this research was to develop more rigorous modeling and analysis methods utilizing software typically available to TxDOT and their consultant bridge designers. These analysis and modeling methods take into account the capacity of the fractured girder, especially at support locations, and realistically model the load distribution between the intact girder and the fractured girder. However, the modeling and analysis methods need to be sufficiently straightforward to be applied on a large scale to the inventory of steel tub bridges. The analysis method developed will meet the requirements outlined in the Federal Highway Administration (FHWA) Memorandum (FHWA 2012).

Project Number

0-6937

Status

Completed

link icon Copy link to this project.