ENHANCING THE ROLE OF BENT-UP BARS IN SHEAR BEYOND THE CODE REQUIREMENTS BY USING PLANE-CRACK INTERCEPTOR-CROSS DIAGONAL FORM

Abstract

Swimmer bars are a new type of shears reinforcement; these are small inclined bars, with their both ends bent horizontally for a short distance; welded to both top and bottom longitudinal steel reinforcement, or welded to hanger bars when compression reinforcement is absent. Regardless of the number of swimmer bars used in each inclined plane, the system forms with the added horizontal bars planecrack interceptor instead of bars-crack interceptors. The results obtained from the testing of beams provided with this system, and the effectiveness of this new system is discussed. The width of the shear cracks was much smaller than the width of the shear cracks in beams reinforced by the traditional stirrup's system. The equivalent steel amount used to replace the conventional steel for the same purposes showed the superior performance of this system over the conventional system; especially when a smaller amount of reinforcement was used by the new system preventing shear failure that took place for the beams which are reinforced with the conventional shear reinforcement. The system used to replace the congestion of stirrups when high shears forces exist.