截面尺寸误差对混凝土框架节点抗震性能影响的试验研究

Influence of section-dimension error on the seismic performance of reinforced concrete beam-column-joint

研究截面尺寸的施工误差对混凝土框架结构在低周往复荷载作用下节点滞回性能的影响。为此,制作了3个配筋相同、截面尺寸误差不同、轴向长度相同十字形框架节点构件。按照相同轴压比对试件施加轴向力,水平方向分别采用力和位移加载方式,研究不同误差的3个节点在低周往复荷载下的性能。得到了3个误差不同的试件的滞回曲线、骨架曲线。试验结果表明:超出现行规范允许值的不同误差的试件开裂荷载、破坏特征是不同的;在相同的轴压比条件下,截面尺寸相对较大的试件相对于截面较小的构件,耗能系数较大10%左右;截面尺寸大的试件相对于截面尺寸较小的试件,前者经历的最大荷载明显大于截面尺寸误差为负值的试件,两者相差达到38%。在相同加载制度下正误差的试件极限位移大于误差为负值的试件,两者相差为5%,前者的变形能力大于后者。因而混凝土框架结构施工环节应严格控制截面尺寸,避免截面尺寸小于设计值的情况,以保证框架结构在动荷载作用下具有良好的抗震性能。

To study the influence of beam-column joints＇ dimension errors induced by the construction process on the seismic performance of reinforced concrete frame joint,three beam-column-joint samples in cross shape,which had the identical longitudinal length,reinforced bars and different section dimensions,had been made;The vertical concentrated force were loaded at the top end of column,while horizontal reversed cyclic loading were applied at the corner of the loading frame according to the designed loading program.The cracked load,dissipation capacity and load-displacement hysteretic curve were obtained.The results demonstrate that dissipative coefficients of large dimensional sample is roughly 110% as large as the coefficient of smaller sample,the history maximum displacement of tested samples with larger section are 38% larger than that of smaller specimens,and the deformed capacity with larger section dimension is 5% stronger than that of the specimens with smaller section dimension under the same constant axial loading and horizontal cyclic loading.To make the reinforced concrete frame structure have good ductility and energy dissipation capacity,measures must be taken to control the errors of dimensions strictly during the construction process and avoid the real dimension being smaller than designing section size value.