Post-fire tensile properties of half-grouted sleeve connection under different cooling paths

Half-grouted sleeve connections (HGSCs), which are extensively used in prefabricated concrete (PC) structures, have attracted considerable research interest, including their mechanical properties under fire. However, research on the post-fire behaviors of this type of connection under different cooling methods and paths is limited. To fill this knowledge gap, the present work presents the experimental results of 33 HGSC specimens subjected to various peak temperatures and different cooling methods. Results show post-fire tensile properties are significantly affected by the exposed peak temperature and subsequent cooling method. Two types of failure modes are observed on the basis of the exposed peak temperature and cooling method, namely, rebar tension fracture and bond failure. The bond length of HGSC designed for room temperature is sufficient after a fire if the connection is naturally or air-cooled after peak temperature; whereas the bond length must be increased if water cooling is applied. Finally, a set of stress–strain relationships of HGSC and rebar is suggested for the post-fire performance evaluation and numerical simulation of PC structures with HGSCs.