Shear Strengthening of Reinforced Concrete Beam with High-Performance Fiber-Reinforced Cementitious Composite Jacketing

摘要

The possibility of using thin high-performance jackets aimed at improving the structural and shear capacity of existing reinforced concrete members is investigated in this paper. The jackets are made of high-performance fiber-reinforced concrete, with a steel mesh fabric sometimes added (diameter of the wires = 2 mm [0.078 in.]; wire spacing = 25.4 mm [1 in.]; and ultimate strength of steel = 550 N/mm~2 [79.8 ksi]). Two different high-performance cementitious composites are investigated: a self-leveling concrete suitable for casting thin members, and a thixotropic concrete requiring no molds during casting operations. To assess the effectiveness of the proposed solutions, different jackets were used to reinforce short, simply supported reinforced concrete beams (2.85 m [9.35 ft] long) lacking stirrups. The beams were tested up to failure in four-point bending, and the numerous test results, including a close comparison with the reference unstrengthened beam, are presented and discussed. The experimental results demonstrate the effectiveness of the technique proposed. All strengthened beams reached their theoretical bending capacity, whereas the unreinforced beam failed in shear.