Semester

Spring

Date of Graduation

2012

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

Karl E Barth

Committee Co-Chair

Udaya B Halabe

Committee Member

John P Zaniewski

Abstract

On December 15, 1967, the Silver Bridge across the Ohio River catastrophically collapsed, resulting in the deaths of 46 people. Following the collapse of the Silver Bridge, one of the goals of the development of new bridge inspection and design guidelines was to create a more uniform level of safety in the U.S. highway infrastructure by standardizing inspection frequencies and qualifications for bridges. It was believed that regular maintenance procedures assured that these types of bridge systems possessed acceptable levels of safety. However, on August 1, 2007, the I-35-W Bridge in Minneapolis, MN, collapsed, resulting in 13 fatalities and 145 injuries. Its failure, like that of the Silver Bridge, was the result of failure of a single structural element.;Many engineers and researchers have classified these bridges as nonredundant, as failure of a single member/element caused failure, or in these cases, collapse, of the entire bridge. These types of structural failures have led the structural research community in an effort to quantify redundancy in highway bridge superstructures. Throughout the years, many researchers have done studies on levels of redundancy in highway bridges and presented methods (both deterministic- and probabilistically-based) for quantifying bridge redundancy. However, there is no method which is universally accepted; this is apparent when reviewing the current edition of the AASHTO LRFD Bridge Design Specifications (2010), which still incorporates an individual member design approach and does not address the concept of structural redundancy in any direct manner. In addition, in the bridge community there is disagreement as to what the actual definition of structural redundancy should be and what failure criteria should be considered.;The goal of this project is to develop appropriate protocols for assessing redundancy in steel truss highway bridges. To accomplish this, an extensive literature review was performed, focused on reviewing past studies on structural redundancy in highway bridges. Once performed, a set of redundancy protocols were developed, incorporating modern finite element modeling techniques and limit states associated with system capacity under damaged conditions. To validate the proposed modeling technique, a field test was performed on a representative truss bridge in Jackson County, WV. Once validated with experimental data, these protocols were then exercised on the representative truss to determine the effect of damaged conditions on system capacity of steel truss bridges.

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