型钢混凝土框架静力非线性分析塑性铰参数研究

Determination of plastic hinge property for steel reinforced concrete frame in nonlinear static analysis

SRC构件具有比普通RC构件更高的承载力和极限变形能力.但由于SRC构件塑性铰属性参数较难确定,使该结构很难直接应用静力非线性方法进行分析,而是转化为等刚度的RC构件进行计算.从理论上给出了SRC框架压弯构件PMM铰N-Mx-My相关面的形成方法,提出了型钢混凝土构件弯矩-曲率曲线的确定及将其转化为杆单元塑性铰弯矩-曲率关系的方法,并得到了塑性铰区长度的计算方法.应用确定的铰属性参数对两跨三层SRC框架进行了静力非线性分析,结果与振动台试验吻合较好,表明这种铰属性参数用于SRC构件静力非线性分析是合适的.最后通过与具有相同刚度的RC框架计算结果对比分析,表明采用这种刚度相等的RC构件进行计算低估了SRC框架的抗震能力.

Steel reinforced concrete （SRC）structures have lots of advantages over reinforced concrete （RC） structures in strength and ultimate deflection capacity. Because there are some problems on the determination of plastic hinge property for SRC members, it is difficult to carry out nonlinear static analysis directly to this structure, which is usually substituted by reinforced concrete member with equal rigidity when Pushover analysis is needed. This paper presents the computing methods of N-Mx-My interaction surface of SRC members PMM plastic hinges theoretically, gives the determination means of curve of SRC member, puts forward the principle to form curve of PMM hinge transformed from that of SRC member, and provides the calculation formula of plastic hinge length. According to the proposed method, Pushover analysis is performed on a SRC frame with two bays and three stories, of which the results are in good agreement with that of the test. This indicates that the plastic hinge property defined in the paper is proper, and may be referenced for SRC structure nonlinear static analysis. Finally, a comparative study is carried out between SRC frame and RC frame with equal rigidity, which demonstrates that seismic behavior of the SRC structure will be underestimated when it is substituted by the RC structure with equal rigidity.