Experimental Study of Reinforced Concrete Double Corbels Containing Steel Fibers Subjected to Eccentric Vertical Loads

This research aims to investigate experimentally the torsional resistance of reinforced concrete (RC) double corbels and the effects of load eccentricity, variation of vertical, horizontal stirrups and corbel width. In the conducted experimental program, nine reinforced concrete (RC) double corbels containing fibers were cast and tested under centric and eccentric static vertical load until failure. Steel fibers have been added to the concrete mix to enhance concrete characteristics such as toughness, stiffness and strength, in addition to limiting micro crack propagation. The tested RC corbels had different widths and different amounts of vertical and horizontal stirrups. The experimental results studied are: (1) First crack load; (2) Maximum torque moment; (3) Twisting angle; (4) Displacement corresponding to the first crack load (5) Displacement corresponding to the failure moment; (6) Cracking pattern; (7) Displacement ductility; (8) Toughness; and (9) Failure mode. The experimental results showed that by increasing reinforcement of vertical stirrups and horizontal stirrups the ultimate torque of the tested specimens increased by 4.58% to 17.96% while increasing corbels width increased the ultimate torque by 24.32%. It can thus be concluded that the use of vertical and horizontal stirrups and increasing the corbel width caused noticeable improvement of the cracking and ultimate torque for RC corbels under eccentric vertical loads.