Structural Torsion Effect Characteristic Study On L-plan Frame Structure Under Seismic Effect

Complex and other irregular architectural structures, increase gradually along with the development of the national economy, and become a trend of buildings. But every past earthquake damage shows that the irregular plane structure is easy to cause obvious torsion damage. In order to protect the life property and security and raise the level of anti-seismic design, it’s is necessary to carry out the research for torsion response of irregular structure on seismic action. In this paper, the torsion effect of one irregular structure-the L-plane irregular multilayer frame structure of seismic action is analyzed to have a deeply understanding in this kind of structure conceptively, and also to lay the foundation for the further research.Through the establishment of equal floors quality model, three equal limb multilayer L-plan frame structure model, discussion on the modal of multilayer L-plan frame structure is presented in this paper to be concluded that the difference of mass distribution and eccentricity make the change of modal little in L-plan frame structure. By using a method of response spectrum method based on vibration separated, the torsional control parameters of L-shaped frame structure are solved on small horizontal seismic action (unidirectional and bidirectional seismic action). Through the analysis of calculation results, we can conclude some general rules, include that the torsion reaction and mass distribution of elastic stage is most close to the eccentricity ratio. And when the double eccentricity is large, the bi-directional earthquake function should be considered.By using the static elastic-plastic analysis method such as Pushover method, the structural elastic-plastic peculiarity of three equal limb multilayer L-plan frame structure model can be analysed on severe horizontal seismic action(X axis or Y axis unidirectional seismic action). Observing the curve of base shear to displacement the structural torsion parameters on performance point and the order of plastic hinge, we can come to the following conclusions. First, the bearing capacity and quality are closely related to the distribution and eccentricity of thus structure on severe seismic action. Second, the structural torsion effect is mostly obvious when the massive ones are uneven distributed and the double eccentricity is largened.