钢筋混凝土柱弯矩-转角骨架线特征点及性能点转角研究  

Study on rotation angles at characteristic point and performance point of M-θ skeleton curve for RC columns

作　　者：钱稼茹[1] 冯宝锐[1] 

机构地区：[1]清华大学土木工程安全与耐久教育部重点实验室,北京100084

出　　处：《建筑结构学报》2014年第11期10-19,共10页Journal of Building Structures

基　　金：国家自然科学基金重大研究项目(91315301)

摘　　要：基于不同抗震等级钢筋混凝土(RC)柱拟静力试验研究,建议了RC柱四折线弯矩-转角(M-θ)骨架线。采用规范公式计算得到的RC柱的正截面承载力作为M-θ骨架线的峰值弯矩M_p,0.8M_p作为M-θ骨架线名义屈服点弯矩,下降至0.8M_p及0.75M_p(不考虑P-△效应)分别作为M-θ骨架线极限点的弯矩及失效点的弯矩,根据继续使用性能点i0及生命安全性能L的转角表达式,分别确定其弯矩为0.9M_p及下降至0.925M_p。基于由0penSEES数值计算得到的按规范最小配箍特征值配置箍筋的22根RC柱的水平荷载-位移(F-△)滞回曲线得到的M-θ骨架线,确定了RC柱四折线M-θ骨架线特征点及性能点的转角,确定的转角与试验值符合较好;对于生命安全性能点LS、避免倒塌性能点CP及失效点的转角,当轴压比为0.5时,其与美国标准的规定基本一致,当轴压比为0.9时,其大于美国标准的规定。提出了RC柱的损坏程度与其M-θ骨架线特征点及性能点转角的关系,可用于判别地震作用下RC框架柱的损坏程度以及是否达到其预定的抗震性能目标。On the basis of quasi-static test study of different seismic grade reinforcement concrete（RC） columns,a four-linear bending moment-rotation angle（M-θ） skeleton curve for RC columns is proposed.The normal section capacity of RC column calculated by code formula serves as the peak bending moment M_p of the M-θ skeleton curve.The bending moment at the nominal yield point of the M-θ skeleton curve is taken as 0.8M_p.The bending moments dropped to 0.85M_p and 0.75M_p（P-△ effects not included） are taken as the moments at the performance point CP and at the failure point of the M-θ skeleton curve respectively.Based on the formula for calculating the rotation angle at the performance points 10 and LS the bending moments at these two performance points are taken as 0.9M_p and dropped to0.925M_p respectively.Using program OpenSEES,lateral force-displacement hysteretic loops of 22 RC columns are obtained.Then the M-θ skeleton curves of 22 RC columns are also obtained.The stirrup characteristic value of 22 RC columns satisfies the Chinese code required minimum value which is related to the seismic grade and the axial compressive force ratio of the column.From the M-θ skeleton curves,the rotation angles at the characteristic points and at the performance points of the M-θ skeleton curve of RC column are determined,and the determined rotation angles have good agreement with the test values.The rotation angles at the performance points LS and CP and at the failure point are about the same as these specified by the American standards at the axial force ratio 0.5.They are larger than the values specified by the American standards at the axial force ratio 0.9.Finally the relationship between damage extent and rotation angles at the characteristic points and performance points of M-θ skeleton curve is proposed for RC columns.It can be used to judge the damage extent of RC columns and to judge whether RC columns reach the seismic performance target under the action of earthquake ground motions.

关 键 词：钢筋混凝土柱 最小配箍特征值 四折线M-θ骨架线 特征点和性能点 转角 

分 类 号：TU375.3[建筑科学—结构工程]