Fatigue Behavior of Welded Shear Studs in Precast Composite Beams

Abstract

Bridges consisting of full-depth precast concrete deck panels connected to steel girders are an increasingly popular option for accelerated bridge replacement. In designing the shear connectors for this bridge type, fatigue is often the governing failure mode. Typically, design provisions developed for cast-in-place deck systems are used. To date, only limited efforts have been undertaken to assess these provisions for precast applications. Most of the data has been obtained from push tests under constant-amplitude loading conditions. Against this background, this article presents measured strain, fatigue life, and autopsy results for 12 composite beam specimens (6 with precast concrete slabs) subjected to a variable-amplitude loading history until multiple stud failures were observed. The results indicate that shear studs in beams with precast slabs exhibit a fatigue performance at least on par with those in beams with cast-in-place slabs. In addition to yielding valuable fatigue data, the test results provide evidence of the effects of redundancy and the value of beam tests, rather than push tests, for assessing and designing shear connectors.