Effects of CFRP retrofit on impact response of shear-deficient scaled reinforced concrete beams

Abstract

An experimental procedure is carried out to investigate response features of semi-deep reinforced concrete (RC) beams with domi-nant static shear failure subjected to low-velocity impact dynamic load both in intact and retrofitted cases. Built specimens have scaled geometry and material properties preserving physical simi-larity with full-scale members and are strengthened using external-ly bonded carbon fiber reinforced polymer (CFRP) sheets. Con-ducted tests gather reliable and robust data revealing notable stiffness and strength recovery within skin attachment. Desired performance criterion is detected here as concrete flexural cracking along span only when brittle shear collapse is prevented. Peak absorbed impulse capacity is attained for unidirectional carbon fiber retrofit. Stiffness is recovered initially during first impacts and then starts degrading due to rupture of horizontal fibers in cross-ply retrofit, but provided stiffness is stable for unidirectional retrofit during all impacts.