Abstract
Abstract
The present investigation examines experimentally the behavior and ultimate shear strength of reinforced high-strength concrete corbels subjected to vertical load. The experimental investigation consist of casting and testing fourteen reinforced high-strength concrete corbels, the main variables studied were concrete compressive strength (40 to 62 MPa), main reinforcement ratio (0.517 %, 0.776 % and 1.034 %), shear reinforcement stress (ρhfyh=1.535, 2.305 and 3.071 MPa), and the ratio of outside depth to the total depth of the corbel (k/h= 0.24 to 1.00).
The results indicate that high-strength concrete corbels (fc'= 40 to 62 MPa) behaved similarly to those made with normal strength concrete, the increase in compressive strength of concrete leads to increase in ultimate shear strength with ductile failure. By increasing fc' from 40 to 62 MPa for ρh.fyh equal to 1.535 MPa and 2.305 MPa, the ultimate shear strength increased by about 20.8% and 27.5% respectively. An increase in ρw by about 100% caused an increase in load carrying capacity by about 27.7%. Also by increasing ρh.fyh by about 100%, the ultimate shear strength increased by about 14.7% and 11.1% for corbels with fc' equal to 40 and 49 MPa respectively, while for corbels with fc' equal to 62 MPa, an increase in horizontal shear reinforcement stress (ρh.fyh) by about 50% caused an increase in ultimate shear strength by about 12.3%, and this indicate that the contribution of horizontal stirrups in increasing ultimate shear strength was more efficient for corbels having compressive strength equal to 62 MPa. As (k/h) increased from 0.24 to 1.00, the ultimate shear strength increased by 11.5%.
Keywords: Corbel, high strength concrete, shear strength, strut and tie model.
