Cathy French, I.T. Distinguished Professor, Civil Engineering
The Minnesota Department of Transportation (MnDOT) has developed a design for a precast composite slab-span system (PCSSS) to be used in accelerated bridge construction. The system consists of shallow inverted-tee precast beams placed between supports with cast-in-place (CIP) concrete placed on top, forming a composite slab-span system. Suitable for spans between 20 and 60 feet, the MnDOT PCSSS is useful for replacing a large number of aging conventional slab-span bridges throughout the United States highway system. The PCSSS, however, has particular durability, constructability, and economical concerns that affect its value as a viable bridge design. To address these concerns, this project evaluated the performance of existing PCSSS bridges and reviewed a number of PCSSS design details. The field inspections demonstrated that design changes made to the PCSSS over its development have improved performance. A parametric design study was also conducted to investigate the effects of continuity design on the economy of the PCSSS. It was recommended that the PCSSS be designed as simply supported rather than as a continuous system.