Optimizing the use of swimmer bars as shear reinforcement in the reinforced concrete beams

The sudden failure of the reinforced concrete beams due to shear made it necessary to explore more effective ways to design these beams. The reinforced concrete beams show different behavior at the failure stage in shear compare to the bending, which is considered to be unsafe mode of failure. The shear failure of beams is usually sudden without sufficient advanced warning, and the diagonal cracks that develop due to excess shear forces are considerably wider than the flexural cracks. The cost and safety of shear reinforcement in reinforced concrete beams led to the study of other alternatives. Swimmer bar system is a new type of shear reinforcement. It is a small inclined bars, with its both ends bent horizontally for a short distance and welded to both top and bottom flexural steel reinforcement. Regardless of the number of swimmer bars used in each inclined plane, the swimmer bars form plane-crack interceptor system instead of bar-crack interceptor system when stirrups are used. Three different shapes of swimmer bar system were explored in this study. The main purpose is to identify the most efficient shape to carry shear forces at the lowest cost. Several reinforced concrete beams were carefully prepared and tested in the lab. The results of these tests will be presented and discussed. The deflection of each beam is also measure at a given applied load. The propagation of shear cracks was also closely monitored.