Experimental and analytical investigations on the effect of steel fibers on the crack behavior and strength of dapped‐end connections

Abstract
Reinforced concrete (RC) dapped‐end connections feature a sharp re‐entrant corner subjected to high stress concentrations, leading to wide cracks under service loads and potential durability issues such as reinforcement corrosion. Effective crack control is therefore essential in the design of new dapped‐end connections. Steel fiber reinforced concrete (SFRC) has shown potential to improve crack control while also enhancing ultimate strength. This study proposes a kinematics‐based model to describe the response of SFRC dapped ends along the re‐entrant corner crack. Appropriate constitutive relationships are used to link the deformations along the corner crack and the compression zone to the resisting forces: reinforcement and SFRC in compression and tension. The model is validated against eight large‐scale tests with varying fiber amounts including detailed deformation measurements from which the resisting mechanisms and crack‐opening behavior are derived. The experimental results show that a fiber amount of 70 kg/m3 reduces the crack width by about 40%, enabling compliance with code requirements. The validation demonstrates that the proposed model represents a reliable tool for designing SFRC dapped‐end connections at both service and ultimate limit states.