Experimental study on effect of sleeve grouting defects on seismic behavior of precast concrete columns

In order to experimentally investigate the effects of grouting defects on the seismic behavior of precast concrete columns connected with grouted sleeves, which are widely used at present, a total of seven precast concrete column specimens and one comparison specimen of cast-in-site column were designed. Two types of grouting defects with different sizes, namely 'reflowing of grout' and 'no grouting at all' were preset in one row of sleeves. Low cyclic reversed loading tests were performed to analyze the seismic behavior of the specimens such as failure modes, hysteresis characteristics, load-carrying capacity and energy dissipation capacity. The results show that two flexural failure modes occur to specimens, that is, failure at column bottom section and failure at the section around sleeve top. The failure mode of the intact precast column specimen is the same as that of the cast-in-site column specimen, and the load-carrying capacity is similar. Compared with the intact precast column specimen, the positive peak load of the precast column specimens with grouting defects is reduced by 6% to 44%, the displacement ductility coefficient is reduced by 1% to 43%, and the total cumulative energy dissipation is reduced by 37% to 63%. The grouting defects with a height exceeding 33%of the anchorage length of steel bar on one side of the full grouting sleeve have large adverse effects on the hysteretic characteristics, load-carrying capacity, ductility and energy dissipation capacity of the precast columns. © 2022, Editorial Office of Journal of Building Structures. All right reserved.