应变率效应对600 MPa级高强钢筋混凝土框架结构抗震性能影响研究

Study on effect of strain rate on seismic performance of concrete frame structure with 600 MPa grade high strength bars

为了更真实地进行钢筋混凝土结构抗震性能评估,应该考虑材料的应变率效应影响。600 MPa级高强钢筋作为新一代建筑钢材,尚无考虑应变率效应影响的600 MPa级高强钢筋混凝土框架结构抗震性能研究。首先进行了不同应变率下600 MPa级高强钢筋拉伸力学性能试验,利用试验数据拟合得到600 MPa级高强钢筋在不同应变率下的强度提高系数表达式,并利用OpenSees软件进行了配置600 MPa级高强钢筋混凝土框架结构抗震性能模拟分析,研究了应变率效应对框架结构抗震性能的影响。研究结果表明:随着应变率的增大,钢筋的屈服强度和极限强度均得到提高,屈服强度最大提高11.5%,极限强度最大提高8.9%;随着所考虑的材料应变率增加,配置600 MPa级高强钢筋框架结构最大顶点位移总体上呈减小趋势,地震波强度越强,应变率效应影响越大,而层间位移角减小幅值相差不大。研究成果可作为600MPa级高强钢筋混凝土框架结构抗震评估的依据。

In order to evaluate the seismic performance of the reinforced concrete structures more realistically,the strain rate effect of materials should be considered.As 600 MPa grade high strength bar is a new generation of building steel,no research has been available on the seismic performance of the reinforced concrete frame structure using steel bars considering the strain rate effect.In this study,the tensile mechanical properties of 600 MPa grade high strength bar under different strain rates were studied,and a formula to estimate the strength increase due to strain rate effect was achieved by using experimental data fitting.The seismic performance of the reinforced concrete frame structure with 600 MPa grade high strength bars was examined using the software of OpenSees,and the effect of strain rate on the structural seismic performance was studied.The results show that the yield strength and ultimate strength of the reinforcement grow with the increase of strain rate,and the yield strength is increased by 11.5%and the ultimate strength increased by 8.9%.With the increase of the material strain rate,the maximum roof displacement of the frame structure generally decreases.The stronger the seismic wave intensity is,the greater the strain rate effect is,and the difference of the increased amplitude is limited.The research results can be used as the basis for the seismic performance evaluation of the frame structure with 600 MPa grade high strength bars.