Seismic performances of post-fire precast high-performance concrete column with grouted sleeve connections

Considering the effects of heating time and the assembled method of the connection, a low-cyclic loading experiment was conducted to investigate the seismic performance of high-performance concrete columns, including a cast-in-place specimen and three precast specimens with grouted sleeve connections. The addition of polypropylene fibers (PPF) effectively inhibited explosive spalling in the high-performance concrete column specimens when exposed to fire for up to 120 min. Furthermore, the fire resistance of the precast high-performance concrete column with grouted sleeve connections exceeded 2 h. The 25 mm thick concrete protective layer effectively delayed heat transfer within the cross-section depth of the precast column specimens, reducing the maximum temperature by up to 54.3 % compared to the furnace temperature. The seismic performance of the precast high-performance concrete column with grouted sleeve connections (PC) was equivalent to that of the cast-in-place high-performance concrete column (CC) at ambient temperature. The displacement ductility, accumulated hysteretic energy, and peak load of post-fire PCs decreased as the heating time increased to 120 min, causing a decline of 37.2 %, 20.0 %, and 15.6 % compared to those of PC at ambient temperature, respectively. Based on the equivalence of cross-section width, a method was developed to calculate the shear-bearing capacity of post-fire PCs. These findings contribute to the safety application of PC in seismic zones.