An investigation of reflective cracking and empirical development of design specifications for precast composite slab span system (MnDOT PCSSS) superstructures.

Abstract

The need to replace the deteriorating highway bridge infrastructure in the United States while minimizing the disruption to motorists has promoted the development of innovative construction techniques. To address this demand, a promising design has been developed by the Minnesota Department of Transportation (MnDOT) based on the French Poutre Dalle slab span bridge system. The MnDOT design, which is a precast composite slab span system (PCSSS), is practical for short to moderate spans up to approximately 65 ft. The PCSSS design requires no formwork or shoring during the construction process, while also making use of precast elements without the need for transverse post-tensioning. A significant deterrent to the implementation of the PCSSS nationally was the lack of detailed design specifications and limited knowledge of the behavior of the system. To address these limitations, the current study involved the development of several large scale laboratory research specimens with the objective of investigating the development and control of reflective cracking at the discontinuities created by the longitudinal joints between adjacent precast panels. Also considered during this study included the effects and necessity of horizontal tie reinforcement on the development of composite action in the PCSSS. This paper describes the laboratory investigation and analysis of the MnDOT PCSSS in reference to these behaviors and the development of a comprehensive design guide and code specifications for the AASHTO LRFD Bridge Design Specifications.