高层建筑隔震分析中作用效应组合方式探讨

Discussion for effect combinations of high-rise building isolation analysis

通过理论公式推导,对不同隔震支座拉压刚度比下,采用线性组合法(LCM)和非线性组合法(NLCM)对隔震层受拉程度的影响进行了研究,并结合某高层建筑隔震实例,分析了采用线性组合法计算上部结构效应的误差。研究结果表明:相对于非线性组合法,由线性组合法计算得出的隔震层受拉区长度偏小,且偏差程度随着隔震支座拉压刚度比的减小而增大,即偏于不安全;当采用线性组合法时,部分楼层减震系数、隔震支座最大位移、最大拉应力、最大剪力以及部分隔震支座最大压力和压应力均偏小,即线性组合法计算结果偏于不安全;高层隔震计算中应考虑支座拉压刚度不等性,即应按实际荷载工况顺序依次加载(NLCM),且要考虑上部结构的重力二阶效应。

Through deducing theoretical formulas,the influences of linear combination method（ LCM） and nonlinear combination method（ NLCM） on tensional degree of isolation layer were researched. Based on the case study of a practical high-rise isolation building,the deviation in calculation results of upper structure effect with LCM was analyzed. It is concluded that： compared to NLCM,a more conservative calculation result of tensional region length of isolation layer is obtained by LCM,and the deviation degree increases with the decrease of isolation bearing tension-compression stiffness ratio,which means an unsafely isolating design of high-rise buildings. The calculation results of LCM are generally less than those of NLCM,including factors of seismic reduction coefficients of some layers,maximum displacement of isolation bearing,maximum tensile stress,maximum shear force,as well as maximum compression force and maximum compression stress of some isolation bearings,which means an unsafe result of LCM. Differences in the tension and compression stiffness of isolation bearing should be considered in high-rise building isolation calculation. The loading sequence should follow in the order of the actual loading conditions（ NLCM）,and second-order gravity effect of the upper structure should be considered.