Study On Torsion Design For Horizontal Irregular Buildings Under Effect Of Earthquake

Modern high-rise buildings usually occurred with different irregular structure due to the special requirement of function and facade effect. Hereinto, the problem of irregular torsion is especially outstanding and common. The tensibility of these buildings is not very good, so the structural torsional destroy is usually outburst without premonition and lead to grave destroy once earthquake occurred, then we must control the torsional effect of structure during the course of design. JGJ3-2002 controls the structural torsional effect with torsional period ratio and torsional displacement ratio these two indexes. How to satisfy the two controls with certain measures during the structural design is inevitable to all structural designers and a hard problem to deal with, so it is quite necessary to implement the research.This paper probes into the effect factors of structural torsion first, and then summarizes research status about torsional problems in and outside of China, as well as expounds the current relative regulations for structural torsion control. This paper takes one high-rise building with eccentric annexes of Chongqing for example to implement structural torsion design. After a series of comparison and election to several programs, this design gets an appropriate program meet the requirements of structural design and probes into torsion control to high-rise buildings with eccentric annexes based on the program.With the analysis and research above, the main achievements of this paper are as follows:â‘ The design to high-rise buildings with irregular structure must be controlled with torsional period ratio and torsional displacement ratio these two indexes. The designer should adapt measures to adjust the structure arrangement when the two indexes are not satisfied by rearranging the shear walls according to the principle of equality, decentralization, symmetry and surrounding to make horizontal mass center and stiffness centre near. If the structure translational stiffness is too big while the rotational stiffness is not enough, we should not only add shear walls at the periphery of the structure to increase the structure torsional stiffness, but also reduce the amount and thickness of shear walls in the middle of the structure to decrease the translational stiffness.â‘¡Implement torsional design for a building with eccentric annexes, and put...