Date of this Version
Al Badran, M. S., "STRUCTURAL RELIABILITY ANALYSIS OF CORRODED STEEL GIRDER BRIDGE", M.S. Thesis, University of Nebraska - Lincoln, Summer 2013.
The natural aging, environmental impact, and appropriate design are certainly playing a serious role in safety of the bridges function. The functional safety of bridge constitutes a prime element of the transportation system serving commuters, passengers and freight. According to Federal Highway Administration, the steel bridges share represents a large amount of the United States’ bridges. In last century, the collapse of both the Silver Bridge at Point Pleasant, WV over Ohio River on December 15, 1967 and over the Mianus River Bridge in Connecticut on June 28, 1983 showed that steel corrosion has been the leading reason in these disasters. The corrosion occurred when water attacked the steel surface especially in inadequately protected structure from environmental influence or shortcoming in bridge structure. Corrosion form a uniform thickness loss or concentrated pitting depend on size of the affected area, and the location of bridge as which type of the environmental action takes place, and improper design of bridge. To develop a significant deterioration that will be enough to produce a material loss of steel component, which may take several years to happen.
Bridges are designed according to AASHTO-LRFD design code, which stands for the American Association of State Highway and Transportation Officials. To evaluate the effect of corrosion action, a corroded composite steel girder in simple span bridge located in the State of Nebraska was considered for this study. The research focused on ultimate limit state (moment and shear) and serviceability limit state (deflection of beam).
In this study, the corrosion has been modeled for moment and shear stresses with different models and considering three types of corrosion, low, medium and high. Moreover, the steel girder has been modeled using ABAQUS advanced finite element software. Materials specifications, resistance model, and load models were designed using structural reliability techniques. The reliability indices have been calculated to measure the structure performance. The conclusions of this thesis demonstrated that the moment and shear capacity of the analyzed composite steel girder bridge might decrease. According to this conclusion, the live load capacity has also decreased, while the deflection score has increased.
Advisor: Andrzej S. Nowak