Experimental Evaluation of the Static Strength and Ductility of Large Diameter Shear Studs in Composite Bridge Construction

Abstract

A number of bridges in the United States consist of steel girders with concrete decks attached via shear studs which will require replacement in the future. With a growing interest in rapid deck replacement for bridges as the nation’s infrastructure ages and traffic congestion concerns increase, one possible means to accelerate the replacement process is the use of large diameter, 1.25” shear studs, which would reduce the total number of shear connectors needed. The use of these studs is not addressed in the current AASHTO LRFD Bridge Specifications. An experimental procedure was developed to comparatively evaluate the strength and ductility of 1.25” diameter shear studs in two configurations to conventional stud sizes, in this case 7/8” diameter. Flexural strength testing was conducted on four beams, 34 feet in length, with W21x44 steel sections acting compositely with 7” thick, 3 feet wide reinforced concrete decks. The results indicate that a reduced number of these large diameter studs do provide adequate strength and ductility for use in composite bridge construction. The research indicates that structures with 1.25” large diameter shear studs may be safely designed using current strength provisions of the AASHTO LRFD Bridge Design Specifications.