Flexural Behavior of Stone Slabs Reinforced with Prestressed NSM CFRP Bars

Abstract

A technique for reinforcing stone slabs with prestressed near-surface mounted (NSM) carbon fiber–reinforced polymer (CFRP) bars is proposed and investigated in this research. Six stone slabs were tested under monotonic loading. Among these slabs, one served as a control slab and was not reinforced, and two were reinforced with one or two NSM CFRP bars, and each bar was prestressed to 30% of the bar’s ultimate strength. The remaining three were reinforced with three NSM CFRP bars that had been prestressed to 0, 15, or 30% of the bar’s ultimate strength. The test results indicate that reinforcement with either prestressed or nonprestressed NSM CFRP bars shifted the failure mode of the stone slabs from abrupt fracture to a more ductile flexural failure. A remarkable improvement in the flexural response was obtained when the stone slabs were reinforced with prestressed NSM CFRP bars. In addition to exhibiting a higher cracking load, the stone slabs that had been reinforced with prestressed NSM CFRP bars exhibited cracks with a smaller width, and the strength utilization of the CFRP reinforcement was much higher compared to that of the nonprestressed reinforced slabs. An analytical model was developed based on a sectional analysis method to predict the flexural response of stone slabs reinforced with prestressed NSM CFRP bars. The predicted values show good agreement with the experimental results.