Comparative Analysis of Shear Reinforcement Shapes in Reinforced Concrete Beams

Abstract

Reinforced concrete beams subjected to high shear force, exhibit a diagonal tension crack, which tends to widen propagate towards the point of loading. Shear failure in reinforced concrete beam is usually sudden without sufficient warning. This type of failure made it necessary to explore more ways that are effective to design of these beams for shear. The two types of reinforcement account for shear are vertical or inclined stirrups. In vertical stirrups, the spacing between stirrups reduced at the supports to resist high shear stresses. However, the congestion near the support of reinforced concrete beams increases the cost and time required for installation. This study focuses on reinforced concrete beam with different shear reinforcement shapes using finite element analysis to identify the most efficient shear reinforcement shapes considering three-span length of reinforced concrete beams having 2m differences (2m,4m, and 6m). Twenty-eight reinforced concrete beams subjected to monotonic loading were compared based on shear strength using different shear reinforcement shapes and angles. The shear reinforcement shapes used in reinforced concrete beams are vertical stirrups considered a control sample, inclined stirrups, swimmer bars, continuous rectangular spirals, and warren truss shapes. Twelve reinforced concrete beams designed considering four-angle of shear reinforcement having 150 inclinations differences (450 ,600 , 750 and 90o ) and compared based on shear strength values obtained manually and by using Tekla Tedds 2019 calculation software based on EN 1992-1-1code [5]. The shear carrying capacity of sixteen reinforced concrete beams using different inclined shear reinforcement shapes was analyzed under four point loading conditions and compared with reinforced concrete beams having vertical stirrups considering the same shear reinforcement spacing using ABAQUS V6.14-5 Software. Reinforced concrete beams with 45o inclined shear reinforcements showed higher shear strength compared to the beams having other angles of inclination based on EC2 design. The increased shear capacity of reinforced concrete beams using swimmer bars, inclined stirrups, warren truss, and rectangular spirals as shear reinforcement shapes compared to reinforced concrete beams with vertical stirrups along 2m, 4m, and 6m span length showed averagely 35%, 30%, 24%, and 17% respectively considering the same shear reinforcement spacing. From the analytical results obtained, the uses of inclined links are an effective technique to enhance the shear capacity of reinforced concrete beams specially using swimmer bar shapes.