基于能力谱法的铸钢节点抗震性能设计研究

Research on the Seismic Performance-Based Design of Cast Steel Joints Based on the Capacity Spectrum Method

基于能力谱法提出了以延性为性能指标的铸钢节点抗震性能设计的一般方法。该方法包含3个步骤:1)建立节点的延性能力曲线;2)建立节点的延性需求曲线;3)根据能力谱法计算节点的性能点。以Y型铸钢节点为例,对不同设计参数取值节点的滞回性能进行分析,并计算出其在特定自振周期下的性能点。研究结果表明:1)满足CECS 235∶2008《铸钢节点应用技术规程》构造要求的Y型铸钢节点具备良好的延性性能;2)最优的d/D取值与结构基本自振周期有关,CSCS 235∶2008中规定的d/D取值范围不是所有结构的最优d/D取值;满足CECS 235∶2008构造要求的Y型铸钢节点才存在理论上的性能点;3)在建立不同阻尼和场地类别下的延性需求曲线后,采用能力谱法可以量化地对规则铸钢节点进行基于延性的抗震性能设计。

According to the capacity spectrum method,the general method for seismic performance-based design of the cast-steel joints is put forward,in which ductility is adopted as the performance index.The method includes three steps:1)establishing the ductility capacity curve of the joint;2)establishing the ductility demand curve of the joint;3)calculating the performance points of the joint according to the capacity spectrum method.Taking the Y-type cast steel joint as an example in this study,the hysteretic curves of the joints with different design parameters were analyzed.Besides,the optimized design parameters for the joint under specific natural period were obtained.The results showed that:1)Y-type cast steel joint showed a good ductility,as long as it could meet the requirements in Technical Specifiation for Application of Connections of Structural Steel Casting(CECS 235∶2008);2)the optimal value of d/D was related to the basic natural vibration period of the structure,the d/D value specified in CECS 235∶2008 was not the optimal value for all structures;3)after establishing ductility demand curves for structure systems with different damping ratios and site types,the numerical seismic performance design that based on the ductility could be carried out for regular cast steel joints by adopting capacity spectrum method.