Bridge Analysis, Design and Repair

Single Abstract

339203 - Repair of Steel Bridge Girder Subjected to Distortion-Induced Fatigue Using both Steel Retrofit and CFRP Composites

Saturday, April 21
8:00 AM - 9:30 AM
Location: 201B

Fatigue damage in steel bridges can result in localized cracking in the structure, causing frequent inspections and costly maintenance and repairs. As highway demands increase and economic constraints further tighten, the need for cost-effective, practical retrofits becomes evermore urgent. One of the most common types of fatigue damage is distortion-induced fatigue. Distortion-induced fatigue commonly occurs at connections of transverse structural members and is thought to be responsible for up to 90% of fatigue cracking in steel bridges. Due to the lack of connection between the girder flanges and the connection stiffeners in steel bridges constructed before 1985, many of these structures have experienced distortion-induced fatigue in web gap regions.
While many methods have been developed for mitigating distortion-induced fatigue cracking, the majority are invasive and disruptive to traffic. Therefore, repair techniques that can effectively repair distortion-induced fatigue damage in steel bridges with minimal disruption to the traveling public are needed. A new retrofit for distortion-induced fatigue, the ‘angles-with-plate’ retrofit, does not produce interference with the concrete deck and can be installed while traffic is maintained. This retrofit consists of two steel angles that are bolted to the transverse connection plate and the web of the steel girder, and a steel plate which is bolted to the opposite side of the web.
On the other hand, strengthening steel structures using externally bonded Carbon Fiber Reinforced Polymers (CFRP) has received much attention over the last decades; however, little research on strengthening steel bridges subjected to distortion-induced fatigue with CFRP materials has been carried out. Unlike many traditional repair methods for distortion-induced fatigue, CFRP is less intrusive during the repair process since it can be glued in place, rather than requiring bolting or welding. Moreover, repairs made by bonding CFRP contribute minimal additional weight to the structure and introduce less stress concentrations as compared to mechanical fastening.
The objective of this study aims to study the fatigue behavior of steel bridge girders repaired with a combination of the ‘angles and plate’ retrofit and CFRP composites. A CFRP layer was added to the previously-developed retrofit to engage the girder flange without requiring bolting or welding. The scope of this study includes experimental fatigue testing of a 9-ft long steel plate girder to investigate the performance of the combined retrofit in reducing distortion-induced fatigue crack susceptibility. Additionally, computational simulations were performed using the commercially-available software Abaqus to model the retrofitted girder. The models were used to characterize the efficiency of the combined retrofit and the expected failure mechanism of the CFRP portion of the retrofit.
This presentation is expected to be of interest to designers and academicians, and aims to further expand the available ‘toolkit’ of repair technologies for distortion-induced fatigue that are implementable with minimal disruption to the traveling public.

Hayder I. Al-Salih

PhD student
The University of Kansas

Hayder Al- Salih is a PhD student in the Department of Civil, Environmental and Architectural Engineering at the University of Kansas. He received his BSc and MSc in civil engineering from the University of Babylon-Iraq in 2009 and 2012, respectively. His research interests include strengthening with CFRP composites, fatigue and fracture of steel bridge and finite element analysis of composites materials.

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Adolfo B. Matamoros

Peter T. Flawn Professor
University of Texas at San Antonio

Adolfo B. Matamoros is the Peter T. Flawn Professor in the Department of Civil and Environmental Engineering at the University of Texas at San Antonio. He received his MS and PhD degrees in civil engineering for the University of Illinois at Urbana-Champaign in 1994 and 1999, respectively, and the degree of Licenciado from the University of Costa Rica, in 1989. His research interests include reinforced concrete columns, high-strength concrete, seismic evaluation of older reinforced concrete buildings, shear strength of reinforced concrete and prestressed members, simulations of the nonlinear response of reinforced concrete structures, and fatigue and fracture of steel bridges.

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Jian Li

Assistant Professor
University of Kansas

Jian Li is an assistant professor in the Department of Civil, Environmental and Architectural Engineering at the University of Kansas. He received his MS in 2007 and BS in 2005 from Harbin Institute of Technology in China and his Ph.D. in 2013 from the University of Illinois in Urbana-Champaign, all in Civil Engineering. His research focuses on both theoretical and experimental developments of advanced sensing and health monitoring techniques to improve the resiliency and sustainability of civil infrastructure under operational and extreme loading conditions. His specific research interests include vibration-based damage detection and model updating, wireless smart sensor networks, innovative sensing techniques, computer vision, uncertainty quantification, risk assessment and mitigation. His research is currently funded by various agencies including National Cooperative Highway Research Program, Transportation Pooled Fund Program, Mid-American Transportation Center, and Kansas Department of Transportation.

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Willliam Collins

Assistant Professor
University of Kansas

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339203 - Repair of Steel Bridge Girder Subjected to Distortion-Induced Fatigue Using both Steel Retrofit and CFRP Composites



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