钢框架结构直接基于位移的抗震性能设计

Direct displacement-based seismic performance design of steel frame structures

摘要:

为更好地实现基于性能的抗震设计思想,采用一种直接基于位移的抗震设计方法对钢框架结构进行设计,依据初步设计的结构得到结构的屈服位移,根据大震作用下的设计目标位移,计算相应的延性系数,确定等效黏滞阻尼或强度折减系数,从而构造相应的高阻尼弹性反应谱或弹塑性反应谱,并得到相应的位移反应谱.以二折线模型模拟结构的性能曲线,在位移反应谱上确定结构目标位移对应的结构有效周期,根据有效周期计算结构的刚度,得到结构的设计基底剪力.通过反复改变结构构件的截面使所设计结构的位移与初始假设位移接近,完成结构的设计.通过直接基于位移的设计实现了钢框架结构的预期抗震性能目标,算例分析表明:应用弹塑性反应谱较应用弹性反应谱的设计结果更准确,基于弹塑性反应谱采用直接基于位移的方法可以更好地实现钢框架结构的抗震性能设计.

Abstract:

Direct displacement-based seismic design is a more rational approach to performance-based seismic design,which was used to design steel frame structures.In this method,the yield displacement depends on the initial structures and the ductility factors are calculated according to objective displacement.Then equivalent viscous damping or strength discount factors are ensured,then high damping elastic displacement response spectra or elastic-plastic response displacement spectra are established.Based on structural bilinear model,effective period corresponding to objective displacement are ascertained on displacement response spectra,the structural stiffness and base shear force are confirmed.Component sections are modified to make the structural displacement approach to original displacement,then the structural design are accomplished.Seismic performance objectives of steel frame structures are implemented by the method.Compared to elastic response spectra,the application of elastic-plastic response spectra makes the design results more accurate.Base on elastic-plastic response spectra,performance-based seismic design of steel frame can be implemented by direct displacement-based design method.