A Novel Shear Strength Prediction Approach for Headed Shear Studs Embedded in Ultrahigh-Performance Concrete

Due to the excellent mechanical properties of ultrahigh-performance concrete (UHPC), the shear strength of stud–UHPC composite connections is significantly enhanced. Nevertheless, the underlying mechanism remains not fully understood. This study discusses the process of failure of shear studs embedded in UHPC and develops a concrete wedge block model in an attempt to explain such improvement. The procedure to determine the key characteristics of the wedge block is established. Based on the wedge block model, a modified compression-dispersion model and plastic deformation theory were utilized to derive a shear strength prediction formula for stud–UHPC composite connections. Push-out test results combined with relevant data collected from available literature were used to validate the proposed formula. The deviation of predicted shear strength from experimental results was typically within 25%. The contribution from the UHPC wedge block to the shear strength of the stud–UHPC composite connection was found to be approximately 13%.