Torsion Resistance Design And Research Of High-rise Buliding Considered Additional Torsion

Torsional responses of aseismic structures,especially irregular structures,will exacerbate the damage in earthquakes,which is reflected in previous.It is necessary to propose practical and reasonable measures to control it.Chinese seismic code used now take torsion displacement ratios and period ratios as indices to control it, meanwhile,Torsional displacement ratio and period ratio have theirs irrationality. Theirs irrationality mainly reflects in three aspects as following:(1) Torsion displacement ratios is a relative measurement ,it can not reflect actual deformation of the structure,so it may irrational in practical applications.For example,the eccentric structure with attached house,it bottom displacement is restricted,according to the specification limit,torsion displacement is not allowed,this is unreasonable.As the same,if translational displacement is large,according to the specification,a large torsion displacement is allowed,this is unreasonable too.(2) Torsional period ratios as an index to against structure torsion, in fact defines the structure's torsion stiffness ratio can not be too small, that is the same with torsion displacement ratio in essentially. At the same time, Torsional period ratios is affected largely by eccentricity,so torsional period ratios as a control index need to be discussed.(3) The shear displacement amplification is considered in Chinese seismic code, but did not consider the effect of additional torsion generated by layer twist angle. Additional torsion to the vertical component in the pressure, bending, shear,torsion stress state, reducing the structural safety.To solve the above problem, this paper discusses the relationship between torsional indicators in elastic range,analyze the effect of additional torsion on structure,then put forward designing methods to against torsion.The major work completed and the main conclusions obtained are:(1) Compared and reviewed the national building code of the torsion control index and the torsion design measures.(2) Analyze the torsion regulation and the relationship between the indices of frame structures in elastic range.(3) Designed a reinforced concrete frame structure of fortification intensity 8 according to current design code, and calculated the torque effect generated by torsional angleθon the vertical component.