带可更换构件的RCS混合框架结构受力特性及抗震设计方法

Mechanical behavior and seismic design method of RCS hybrid frame structure with replaceable components

提出一种带可更换构件的RCS混合框架结构,其结构组成包括耗能框架和主框架,利用可更换构件损伤集中耗能,地震后通过更换受损可更换构件实现结构功能快速恢复。采用SAP2000对14榀框架结构进行非线性静力分析,对比研究了混合框架的受力性能,明确了混合框架的屈服机制及受力状态。分析了可更换梁的破坏模式、截面形式及布置位置,耗能框架的跨度及布置位置等参数对混合框架受力特性的影响。基于受力特性分析结果,提出了正常使用、耗能构件可更换、主框架可修复、生命安全及防止倒塌等5个性能水准的划分方法,并将弹性刚度比(KDF/KMF)和屈服位移比(Δ2/Δ1)两个参数作为结构弹性设计的控制参数。采用SAP2000对8榀混合框架结构进行动力时程分析和非线性静力分析,提出了满足不同性能水准的层间位移角限值,以及对结构进行弹性设计时控制参数的取值范围;并结合结构的不同性能目标,进而提出混合框架结构基于双参数的抗震设计方法。研究结果表明,该混合框架结构具有良好的屈服机制,剪切型可更换梁耗能能力较强,自定义截面可更换梁有利于实现结构震后功能恢复,楼面层与层间同时布置可更换梁、增大耗能框架的跨度均能提高结构的刚度和承载力;此外,当弹性刚度比为2.8~4.3,屈服位移比大于1.8时,结构可以达到预期受力状态,且具有较好的可更换性,所提基于双参数的抗震设计方法是有效的。

A hybrid RCS frame structure with replaceable components,consisting of energy dissipation frame and main frame,is proposed in this work.Through the damages of replaceable components to concentrate the seismic energy dissipation,the functions of structures after earthquake can be rapidly recovered by replacing the damaged replaceable components.By using SAP2000,the nonlinear static analyses on 14 frame structures were carried out,and the mechanical behaviors of RCS hybrid frames were compared,so as to clarify the yield mechanism and the stress states of the RCS hybrid frames.The influences of the destruction modes,section types and positions of replaceable beam and the spans and positions of energy-dissipation frame on the mechanical behavior of RCS hybrid frame were analyzed.Based on the analysis results of mechanical behavior,five performance levels of RCS hybrid frame are proposed,towards the purposes of normal use,replaceable energy-dissipation members,repairable main frame,life safety and collapse prevention,respectively.Additionally,the elastic stiffness ratio KDF/KMF and the yield displacement ratioΔ2/Δ1 are used as control parameters for the elastic design of RCS hybrid frame.By using SAP2000,the dynamic time-history analysesand nonlinear static analyses on 8 RCS hybrid frames were carried out.Limit values of inter-story drifts satisfying different performance levels and the ranges of control parameters for elastic design of RCS hybrid frame were proposed.Towards different performance objectives of the frame structure,the dual-parameter seismic design method of RCS hybrid frame was proposed.The research results indicate that the RCS hybrid frame has good yield mechanism;shear-type replaceable beam has good energy-dissipation ability;replaceable beam with user-defined section is beneficial to recovering the functions of structure after earthquake.The stiffness and bearing capacity of the structure can be improved by arranging floor-to-floor replaceable beams and increasing the span of energy-dissipation frames.When KDF/KMF is in the range of 2.8 to 4.3 andΔ2/Δ1 is greater than 1.8,the structure can achieve the expected stress state with good replaceability,and the dual-parameter seismic design method shall be effective.