Dr. Scott Walbridge
Department of Civil and Environmental Engineering, University of Waterloo
Assessment of Fatigue Design
Provisions for Welded Shear Studs in Steel-Concrete Composite Bridges
The shear connection between steel girders and concrete bridge decks is most common commonly made with welded shear stud connectors, primarily due to its ease of installation. However, the detail is fatigue critical because of the presence of the welds. The fatigue design provisions, which nearly always govern for these studs, have not been significantly updated in over fifty years. The aim of this research will be to establish a new endurance limit for welded shear studs and will build on the previous research that has been conducted at the University of Waterloo.
This research project has the following specific objectives: 1) to conduct small-scale laboratory fatigue tests and analysis required to establish the constant amplitude fatigue limit (CAFL) for welded shear studs; 2) to input the statistical parameters from the small-scale test results into a full bridge simulation (already developed model) to investigate full bridge effects; and 3) to perform several tests on bolted shear connectors to confirm their fatigue resistance under high cycle fatigue, and compare it with that of the welded shear studs. The project will include the following major tasks: Experimental Design, fabrication and instrumentation; static control tests; fatigue tests with variable and constant amplitude loading; metallurgical and fracture mechanics analysis; reliability modelling. This project is expected to benefit bridge designers and erectors by providing refined code provisions, which are calibrated to the proper level of risk, and that will result in greater economy, efficiency, durability, and constructability.
Dr. Walbridge is an Associate Professor in Civil Engineering at the University of Waterloo. He came to the University of Waterloo in 2006, after completing his doctoral thesis at the Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland. Dr. Walbridge’s current research focuses on a variety of areas related to the general theme of “the evaluation and maintenance of existing steel bridges”. He is currently overseeing research projects on the use of peening treatments and advanced composite materials for improving the fatigue performance of existing steel bridges. He also has projects underway on: the evaluation and corrosion protection of weathering steel highway bridges, and shear connections for movable steel-concrete composite bridges. Dr. Walbridge serves on a number of design code committees including the Canadian Highway Bridge Design Code (CSA S6) and Welded Steel Construction Code (W59) technical committees. He is also serving as the Director of Waterloo’s new Architectural Engineering undergraduate program.