Shear connections in prestressed beams with precast slabs

Abstract

The prefabricated bridge is an attractive system that can efficiently ease and accelerate the construction and replacement of bridges in urban areas. In order to contribute to its implementation, details of precast slabs for prestressed concrete girders were developed and static tests were conducted in order to propose design equations for the shear connection. Stirrups and stud connectors, used as shear connectors, were fabricated to insert embedded nut-type devices in prestressed concrete girders. Non-shrink mortar was adopted as a filling material in the shear pockets for the connectors. Evaluation of the shear strength developed by the shear connection considering the chemical bond, friction and mechanical connectors was performed to derive an empirical equation for the horizontal shear design of prestressed concrete girders. The presence of mechanical connectors increased the ultimate slip capacity of the shear connection so as to allow the redistribution of shear load, and the suggested details of the shear connection exhibited good performance in terms of strength and ductility. Three composite beams were tested to verify the suggested equation, which revealed that the use of the empirical equations produces a conservative design for horizontal shear of prestressed concrete beam bridges.