I-GIRDER/DECK CONNECTION FOR EFFICIENT DECK REPLACEMENT

Efficient replacement of bridge decks is becoming increasingly important in high traffic areas due to public intolerance to extended bridge closure. Rehabilitation of deteriorated decks causes public inconvenience, travel delay, and economic hardship. Maintaining traffic flow during bridge deck repair is often difficult and requires extensive planning and coordination. Demolition of bridge deck that is compositely connected with either structural steel I-girders or precast concrete I-girders is one of the major items in deck replacement. This is very time consuming because removing concrete around shear connectors takes time and care to avoid damage to the girders. The objective of this research is to implement two new connection systems that were developed in the National Cooperative Highway Research Program (NCHRP) project 12-41, one system for steel girder/concrete deck connection and the other for concrete girder/concrete deck connection. For steel girder/concrete deck connection, a new large 31.8 mm (1 1/4 in.) diameter shear stud is used to replace popular 19.1 mm (3.4 in.) and 22.2 mm (7/8 in.) shear studs. Using the 31.8 mm (1 1/4 in.) studs results in higher construction speed and enhancement of deck removal. For concrete girders, a new debonded shear key system is used to replace the conventional roughened interface system. Shear friction theory is adopted to develop a design procedure for this new connection. Extensive tests and field implementation showed that the new shear key system has comparable structural behavior with the conventional roughened interface system.