The current edition of the Canadian Highway Bridge Design Code (CHBDC) provides limited guidance for the design of composite bridges with precast concrete deck panels and steel girders. The shear connection is critical in determining the overall performance of the composite superstructure and is commonly achieved with a grout blockout in a precast concrete deck panel, which accepts a cluster of tightly spaced steel shear studs. No specific equations are found in the CHBDC for the design of shear studs used in this system. Furthermore, the current longitudinal spacing limitation of 600mm for shear studs in the CHBDC is not conducive to the construction of precast concrete decks where an increased spacing of the stud cluster is desirable. An experimental testing regime was conducted using push-test specimens constructed with precast concrete panels connected to steel flanges with steel studs within a circular grout pocket. Specimens were tested to failure to determine the ultimate capacity of a stud cluster and to investigate the reduction in ultimate strength after cyclic loading. A 36m simple span composite superstructure was designed to the CHBDC. A parametric study is being conducted on the spacing of stud clusters to investigate the serviceability limit state of the composite superstructure using data captured from the push test specimens. Results from the study indicate that clustered shear studs embedded in high strength grout for construction using precast deck panels are suitable for CHBDC requirements and preliminary investigations show that exceeding the code maximum stud spacing of 600mm can be acceptable.
