Experimental investigation on shear fatigue behavior of perfobond strip connectors made of high strength steel and ultra-high performance concrete

This paper explores the fatigue performance of perfobond strip connectors (PBL) made from high-strength steel (HSS) and ultra-high performance concrete (UHPC) by fabricating and testing eight push-out specimens. The failure modes, load-slip curves, stiffness degradation , and residual strength of the PBLs are presented and discussed. The experimental results show that fatigue loads caused connector’s crack formation and stiffness degradation, leading to concrete dowel shear fracture and transeverse rebar bending-shear rupture damage. Compared to the static performance, the fatigue residual strength of the PBL subjected to 0.5 × 10 6 , 1.25 × 10 6 , and 2.0 × 10 6 loading cycles decreases by 1.2 %, 3.6 %, and 14.5 %, respectively, with corresponding reductions in ductility of 14.7 %, 19.4 %, and 4.7 %. Under the same loading cycles, the fatigue residual strength and ductility of the PBL with a maximum repeated load of 0.65 P u are 13.0 % and 3.9 %, respectively, smaller than those of 0.55 P u . A semi-empirical model based on the elastic foundation beam theory and linear cumulative damage model is developed to predict the residual strength of the PBLs using HSS and UHPC. The accuracy and applicability of the model are calibrated using the experimental results. The findings of this study can serve as an experimental foundation and theoretical reference for the fatigue design of PBLs made with high-strength materials. • Fatigue performance of PBLs using HSS and UHPC is experimentally evaluated. • Failure mechanism of the PBLs subjected to fatigue loads is analyzed. • Impacts of loading cycle numbers and upper limit on the PBL are determined. • Analytical model to calculate the PBL’s fatigue residual resistance is derived.