FRP Slab Capacity Using Yield Line Theory

Abstract

Fiber reinforced polymer (FRP) bars have been increasingly used in bridge deck slabs over the last decades to overcome corrosion issues. However, there is still a critical need for a rational method to analyze the load capacity of such bridge deck slabs. Because FRP bars possess a linear stress-strain relationship, the moment-curvature response of FRP concrete section, either reinforced or prestressed, does not exhibit a distinct yield-plateau, thus it is unclear if conventional yield line theory is applicable. Therefore, the concept of an equivalent plastic moment capacity for FRP concrete sections is introduced and applied in yield line theory for bridge deck slabs. A full-scale bridge deck slab with precast panels reinforced and prestressed with aramid fiber reinforced polymer (AFRP) bars is experimentally tested under different wheel and axle load configurations on either interior spans or overhangs. The results confirm the high accuracy of the failure analysis using the yield line theory, where the load capacity predictions are within 3% accuracy of the experimentally observed results.