Analysis On Torsional Effect Of Cross Plan Buildings Under Lateral Loads

With the improvement of the people's living standard, the building structures with irregular and asymmetry plans have been increasing. Under the earthquake conditions, as the structure is complex (the asymmetry buildings, for instance, the buildings whose plan shapes are complex type cross, type L ,type T or etc), and the floor center of mass and the center of rigidity is mismatching, the structure would not only has the horizontal vibration, but also has the torsional vibration, lateral-torsion coupling. And the coupling reaction of the torsional and the lateral vibration will lead to more harder seismic response which harms the structures.This paper analyzes the three factors influencing torsional effect: eccentricity, torsional rigidity, lateral-torsion period ratio, and the three parameters that used for evaluating structural torsional effect: torsion angle, max relative storey drift and the max displacement at the top floor and coefficient of shear.By using the computational software for structure analysis, the three factors influencing torsional effect of single-story buildings are studied and the torsional rigidity, size effect, duplexing earthquake, eccentricity, lateral torsional ratio that effects the cross single-storey structure are analyzed.Through the analysing of the mode of cross plane multi-story and high-rise buildings, the torsional rigidity, widening floors and beams, regular stiffness eccentricity and partial stiffness eccentric, mass eccentricity that affects the cross plane multi-story and high-rising buildings' torsion are analyzed.Finally, based on the analysis and collection of the simulation results above, some suggestion which could be used as design references are presented.