Post-fire seismic performance of precast concrete columns with grouted sleeve connections: An experimental study

This research explores the effects of fire on the seismic behavior of precast concrete columns with grouted sleeve connections. Five precast columns were subjected to fire for 0, 60, and 97 min, then tested under axial loads and horizontal cyclic loading at compression ratios of 0.1 and 0.3. A comparative analysis was performed against a cast-in-place column, identically treated. The study found that fire exposure alters failure modes: non-exposed columns failed flexural, while those exposed for 60 min showed either flexural shear or shear bond failures, varying with axial compression. After 97 min fire exposure, shear bond failure was predominant. Fire exposure duration was inversely proportional to load-bearing capacity, ductility, stiffness, and energy absorption. Conversely, higher axial compression ratios increased load capacity and stiffness but decreased ductility, without significantly affecting energy absorption post-fire. The study culminates in a refined calculation method for estimating post-fire load capacity, achieving accuracy within 5 % error.