Experimental investigation on the dynamic behavior of grouted splice sleeve connector under fast tensile loading

Abstract

This paper presents an experimental program designed to investigate strain rate effects on the bond behavior of grouted splice sleeves connected with deformed steel bars. Thirty-six grouted splice sleeve specimens with different anchorage lengths were designed and tested under direct dynamic tensile loads with four loading strain rates (10−3, 10−1, 10° and 10+1 s−1). Strain gauges were employed to record the strain of the sleeve and rebar. The failure modes and the dynamic bond-slip relationships of specimens were obtained. The results show that the bond force capacity increases with an increase in the strain rate. However, the failure mode shifts from the steel bar fracture towards steel bar pullout as the strain rate increases. The mechanisms of a dynamic load transmission are described based on the experimental results. A dynamic analytical procedure incorporating the strain rate effects was developed to predict the bond force-slip relationships and was validated by comparing the experimental bond force-slip curves. The shifting of failure modes was attributed to the damage aggravation effects of the grouted mortar, which led to a reduced effective anchorage length and a steel bar pullout failure mode at high strain rates. In addition, based on the proposed analytical model, the required anchorage length of grouted splice sleeves at different strain rates was calculated and an empirical model was developed to determine the critical embedment length to facilitate engineering design.