Aseismatic Analysis Of Asymmetric Double-tower Structures With Enlarged Base

The double-tower structures with enlarged base meet the requirements of many owners and architects with the characteristics of the novel architecture and diversified functions, which is also increasingly widely applied in practical engineering. However, due to the sudden change of vertical stiffness in the junction of the base and towers, the structural force becomes complicated. Particularly, for the asymmetric ones of which studying in this article, whose asymmetry and irregularity in the plane arrangement will intensify its torsional response under earthquake. All previous seismic damage shows that high-rise building structures beyond code-specification is prone to overall damage or even collapse. Therefor, it’s of great importance to study on the dynamic characteristics of asymmetric double-tower structures with enlarged base.In this paper, by using structural analysis software SAP2000. Firstly, the modal analysis and the response spectrum analysis of the asymmetric double-tower structure and the single tower structure were done. After that, the elastic time history analysis was done on double-tower structure. The main conclusions are as follows:(1)The mode shapes of the double-tower structure is more complex than the single tower structure, and the lateral-torsional coupling phenonmenon is more serious. Each mode of the two single towers is similar. The model mass participation coefficient of single tower structure is concentrated in the low modes, while the coefficient of c is dispersed in each mode.(2)The connection part of the large base makes the stiffness of double-tower structure enhanced.(3)The dynamic characteristics of double-tower structure is not the sum of the two single tower structure, but making the characteristics reduced of each single tower.(4)The maximum shear force and moment under earthquake waves occurs at the bottom story, and the maximum story drift ratios occurs at the middle story, which is consistent with the result of the response spectrum method.Then, the influence of changing the base and tower parameters on the seismic response was discussed, the result shows that the dynamic characteristics are very complicated. The main conclusions are as follows:(1)Increasing the stiffness of the base can reduce the displacement of top story effectively.(2)Increasing the bottom story height makes the anti-torsion ability and top shear force decrease, the top displacement, the maximum story drift ratios increase.(3)The story number change of left or right tower has little effect on the anti-torsion ability.(4)A reasonable ratio of the left and right tower layers is 0.38-0.69.Finally, based on the performance of the point of view, the static elastic-plastic analysis under the rarely occurred earthquake was done, and the law of the distrubution and development of the plastic hinges and the internal force of the shear wall were summarized, The results show that the structure has the ability to resist rare earthquake, and can ensure the normal use. Further, the bottom and top of the chassis is weak.