Anchorage performance of different punching shear reinforcement elements in cracked concrete

Abstract

Extensive research has been conducted on the bond and anchorage behavior of reinforcement elements in concrete. While many experimental studies have focused on uncracked concrete, the anchorage performance in the presence of cracks remains insufficiently understood. This gap is particularly critical for punching shear reinforcement, which is installed in highly stressed and cracked regions around point supports in flat slabs. To address this issue, the present study comprises 60 pull‐out tests on five types of commonly used punching shear reinforcement elements including hooks, stirrups, and double‐headed studs tested in both uncracked and cracked concrete. Straight bars were additionally examined as reference elements. The experimental program systematically investigated the influence of crack widths up to 2.0 mm on anchorage capacity, slip behavior, and strain distribution. The results show that concrete cracking has a significant influence on the anchorage performance of all types of punching shear reinforcement elements. Despite a general reduction in anchorage stiffness with increasing crack width, only reinforcement types such as straight bars and hooks showed a notable decrease in anchorage capacity, whereas stirrups and double‐headed studs retained their full load‐bearing capacity in cracked concrete. The paper presents experimental results comprising load‐slip curves as well as fiber optic measurements of strains along the anchorage length and assesses the results with different models from the literature.