Effects of grout sleeve defects on the seismic performance of precast concrete shear walls using grouting for low temperature

This paper reports the results of an experimental study on effects of grout sleeve defects on the seismic performance of precast concrete shear walls using grouting for low temperature. Six full-scale precast concrete shear wall specimens were prepared and tested subjected to reversed cyclic loading. Test variables included grouting type, grouting curing condition and grouting defects. Test results indicated that concrete crushing failure and tensile fracture failure of the longitudinal rebars were typical failure modes of all specimens. Concrete around the grouting defects was damaged more seriously due to the stress concentration caused by the grouting defects. The lateral load capacity of W2 using grouting for low temperature and suffered from initial low temperature curing was very close to that of W1 with commonly used grouting cured at normal temperature. This indicated that the grouting for low temperature can mitigate the difficulty of grouting at low temperature. Distance between defect and neutral axis was critical for the hysteretic responses of the shear walls. The defects far away from the neutral axis can lead to more damage on the ductility and energy dissipation capacity than that with the defects near the neutral axis. When the grouting defects were subjected to tension, the lateral capacity decreased gradually with the increase of the distance of the defect to neutral axis. The maximum drop of the lateral capacity of W6 with two grouting defects of the longitudinal rebars in the boundary elements was up to 17 %. The debonding of the longitudinal rebars can cause serious damage to the ductility ratio. The maximum drop of the ductility ratio of W3 with grouting defect of the longitudinal rebar in the boundary elements was up to 32 %.