Flexural behavior of stone slabs strengthened with prestressed NSM steel wire ropes

Abstract

In order to enhance the flexural behavior of the stone building structures, a technique of strengthening stone slabs using prestressed near-surface mounted (NSM) steel wire ropes is proposed. Six strengthened stone slabs were tested under four-point bending by considering the reinforcement ratio, level of prestressing and bonding agent as testing parameters. Additionally, a bare stone slab was also involved in the test program for comparison purpose. It was found from the experimental investigation that, the strengthened stone slabs exhibited ductile failure mode with visible deflection. Formation of multiple cracks in both constant bending zone and flexural-shear zone was observed in the strengthened stone slabs. As expected, abrupt fracture occurred in the bare stone slab as soon as the cracking moment was attained. Besides the improved failure mode, the flexural strength of the strengthened specimens was improved significantly and tended to enhance with the increase of prestressing level. No end slip of the steel wire ropes was observed highlighting the favourable bond characteristics between the constituent elements (steel wire ropes and stone slab). A simplified theoretical model to be used to predict the flexural strength of the strengthened stone slabs was developed and assessed.