Single-lane live load distribution factor for decked precast, prestressed concrete girder bridges

The live load distribution factor equations provided by AASHTO load and resistance factor design specifications for the decked precast, prestressed concrete (DPPC) girder bridge system do not differentiate between a single-lane or a multilane loaded condition. This practice results in a single-lane load rating penalty for DPPC girder bridges. This paper determines distribution factor equations that accurately predict the distribution factor of the DPPC girder bridge system when it is subjected only to single-lane loading. Eight DPPC girder bridges were instrumented. Each bridge was loaded with a single load vehicle to simulate the single-lane loaded condition. The experimental data were used to calibrate grillage models of the DPPC girder bridge system. The calibrated grillage models were used to conduct a parametric study of the DPPC girder bridge system subjected to a single-lane loaded condition. Four new equations that describe the single-lane loaded distribution factor for both shear and moment forces of these bridges are developed in this paper.