Performance evolution of fire damaged grouting sleeves with horizontal defects under cyclic loads

The performance of grouted splice sleeves (GSS) significantly affects the safety of precast concrete buildings. In this paper, high-stress cyclic loading tests were conducted on GSS after elevated temperature to explore the structural performance evolution of GSS with horizontal defects. This study examined the effects of a variety of grouting defect rates of 0, 10, 20 and 30%. The specimens were heated at temperatures of 20, 200, 400 and 600°C. The results showed there were three failure modes for GSS, i.e., rebar fracture, rebar was pulled out before yielding and after yielding. After cyclic loading, the slip of connected rebars of GSS subjected to high temperatures and grout deterioration was gradually increased. Pull-out failure of GSS was also found in the cyclic loading stage. When the grouting defect rate was not less than 20%, the ultimate strength of GSS after exposure to high temperature was significantly degraded under cyclic loading. For GSS with fracture failure, the strength ratios can both meet the requirements. In the case of pull-out failure, the strength ratios of GSS failed to satisfy the requirements. The ductility ratio of GSS under cyclic loading was greater than 4, except for some GSS that failed without yielding of the connected rebar.