柱靴螺栓连接预制混凝土柱抗震性能试验研究

为研究柱靴螺栓连接预制混凝土柱的抗震性能，对4个柱靴螺栓连接预制混凝土柱进行了拟静力试验，并与整浇混凝土柱进行对比，研究其破坏形态、滞回曲线、骨架曲线、位移延性、耗能能力、刚度退化等抗震性能及承载力。此外，还结合相关文献中的试验数据，分析了柱靴与基础连接的转动刚度及接缝承载力。结果表明：柱靴螺栓连接预制柱均发生柱底接缝压弯破坏，且破坏集中在柱靴灌浆区域；轴压比为0.2的柱靴螺栓连接预制柱的底部结合面出现通缝，滞回曲线捏拢严重，其耗能能力较轴压比为0.5柱靴螺栓连接预制柱和相同轴压比整浇柱的差；柱靴螺栓连接预制柱的位移延性系数为3.04~3.79，极限位移角为1/49~1/32，具有较好的位移延性；柱靴与基础连接满足欧盟BS EN 1993-1-8刚性连接性能要求，可按刚性连接设计；对于小偏心受压柱靴螺栓连接预制柱，按JGJ 1—2014计算的正截面承载力与试验值之比平均为0.66，具有较高的安全度，但对于大偏心受压柱靴螺栓连接预制柱，二者之比平均为0.90，安全度偏低。在GB 50010—2010的基础上，引入混凝土极限压应变和抗压强度折减系数，分析了柱底接缝的传力机理，建立了考虑剪切影响的柱底接缝处正截面承载力计算方法。按该方法计算的大偏心受压柱靴螺栓连接预制柱的承载力与试验值之比平均为0.81，与配置高强纵筋整浇柱的平均结果相当。

Experimental study on seismic behaviors of precast concrete columns with column shoes-anchor bolt connection

The seismic behavior of precast concrete columns with column shoes-anchor bolt connection was studied and the results of quasi-static tests on 4 precast concrete columns with column shoes-anchor bolt connection were presented. Failure patterns, hysteretic curves, skeleton curves, ductility, energy dissipation capacity, stiffness degradation and bearing capacity were analyzed and compared with the cast-in-place concrete column. Experimental data of other references were collected to analyze the connection rotation stiffness and bearing capacity. The main results are as follows: for precast concrete columns with column shoes, bending failure occurs at the interface of the column bottom, and the failure concentrates on the grouting area of column shoes. Due to the interface seam and the pinching of hysteretic loops, the energy dissipation capacity of precast concrete columns with column shoes whose axial compression ratio is 0.2, which is worse than that of precast concrete columns with column shoes whose axial compression ratio is 0.5 and the cast-in-place concrete column whose axial compression ratio is 0.2. The displacement ductility coefficients are from 3.04 to 3.79, and the ultimate displacement drifts are from 1/49 to 1/32, which show great ductility. The column shoe-foundation connection meets the rigid connection requirements of BS EN 1993-1-8, so it can be designed as rigid connection. For small-eccentrically compressed precast concrete columns with column shoes, the ratio of bearing capacity calculated by JGJ 1—2014 to the test value is 0.66 on average, with high degree of safety, but for large-eccentrically compressed precast concrete columns with column shoes, the average is 0.90, with low degree of safety. Based on GB 50010—2010, a reduction factor on ultimate compressive strain and compressive strength of concrete was introduced, then a calculation method of bearing capacity at the interface of column bottom considering the effect of shear was established. The ratio of bearing capacity calculated by this method to the test value of large-eccentrically compressed precast concrete columns with column shoes is 0.81 on average, which is similar to that of cast-in-place concrete columns with high-strength longitudinal reinforcement.