罕遇地震作用下巨子型有控结构二阶效应影响分析

Analysis of the Second-Order Effect on the Mega-Sub Controlled Structure System under Rare Earthquake

通过有限元分析软件sap2000建立了巨子型有控结构(MSCSS)的有限元模型,在考虑二阶效应的情况下,对MSCSS进行了罕遇地震作用下的弹塑性时程分析,并与不考虑二阶效应的结构地震响应情况进行比较,研究了二阶效应对塑性铰的生成、结构侧移以及杆件内力的影响。研究结果表明:选择不同地震波激励时,考虑二阶效应的作用会使塑性铰数量分布有不同的变化规律;第二子结构层间侧移受二阶效应的不利影响随楼层增加而增加,最大增幅达到6.4%,同时,巨型柱的弯矩和第二子结构梁弯矩均受到二阶效应不利影响,其最大增幅分别为7.2%和7.4%。因此在对MSCSS进行罕遇地震下的弹塑性响应情况分析时,必须考虑二阶效应对结果的影响。

The finite element software SAP2000 was employed to establish the finite element model of Mega-Sub Controlled Structure System（MSCSS）,and the elasto-plastic time history analysis considering the second-order effect of MSCSS under rare earthquake was carried out.The second-order effect on plastic hinge distribution,structural elasto-plastic story drift and structural internal force was analyzed by comparing with the structure without considering the second-order effect.The results show that：（1）the law of plastic hinge distribution considering the second-order effect is different when we choose different seismic wave excitation;（2）the second-order effect on story drift of second sub-structure is more and more adverse with the increase in floor and the most adverse effect is 6.4%;（3）the bending moment of mega column and second sub-structure beam is adversely affected by the second-order effect,the maximum increase in the amplitude of bending moment is 7.2% for mega column and 7.4% for sub-structure beam.Therefore,the second-order effect must be considered when the MSCSS elasto-plastic response under rare earthquake is analyzed.