Capacity and Load Rating of In-Service Precast Prestressed Concrete Bridge Deck Girders with Transverse Cracks

Precast prestressed concrete (PPC) deck girders are among the most common types of structural systems used for bridges with short-to-medium spans. Although this bridge system is known to experience longitudinal (reflective) cracking, there is little information on the impact of transverse cracking on the structural integrity of these bridges. Transverse cracking of PPC girders can significantly compromise the safety and serviceability of these girders. This study focuses on better understanding the impact of transverse cracks on the residual capacity and load rating analysis of in-service PPC deck girder bridges. To obtain a realistic assessment of the condition of in-service cracked girders, a PPC deck girder with transverse cracks is extracted from a bridge in the field and tested under four-point bending until failure. Finite element analysis is also performed to investigate the capacity of the as-built PPC girder. Finally, decompression stresses in the prestressing steel are predicted from the measured crack width using different crack width models that are recognized in the literature. A transverse crack is found to reduce the load rating capacity of the girder by almost 34% which subsequently reduced the capacity-based load rating factor by 22% under the HS-20 truck load. Although serviceability-based load rating from crack width conservatively provided a negative rating, the flexural testing indicated that the girder could carry over 50% of its nominal and residual capacities while remaining in the elastic range.