Experimental study on post-fire performance of half grouted sleeve connection with construction defect

Abstract

Half grouted sleeve connection (HGSC) is widely used in joining rebars in precast concrete structures. Construction defects and fires are inevitable in practical projects. However, the mechanical behaviors of post-fire HGSC with construction defect remain to be a topic with little research. The present work presents experimental results of 66 post-fire HGSC specimens with construction defect under static tension at room temperatures. Results show that the tensile properties of post-fire HGSC are directly affected by the peak temperature and the construction defect, and some properties are different from that of the rebar. Post-fire HGSC exhibited two main types of failure mode: rebar fracture and bonding failure. The protruded rebar in some post-fire specimens obviously slides before the rebar fractured and the ultimate elongation becomes larger. Different type of construction defect has a different effect on the behavior of the specimens, and the effect depends on the weakening of the effective bond area between rebar and grout. The peak temperature and construction defect may make reliable HGSC be unreliable and not acceptable, once the corresponding peak temperature is near 600 °C. Results also show that the proposed method to simulate the construction defects of HGSC is feasible and the X-ray method is an effective way to detect the defects in HGSC.