Experimental Study For The Substructure Experiment Methodbased On Inflection Point

There are obvious advantages in pseudo dynamic substructure test of the present seismic test method. In recent years many scholars around the world through optimizing numerical integral algorithm or improving loading method to increase the precision of the substructure experiment, but the research of dealing with substructure interface problem is still in its initial stage,which seriously influences the promotion of pseudo dynamic substructure testing method.Usually lower part which can easily access to plastic are treated as of the experimental substructure, the upper structure as calculated substructure in pseudo dynamic substructure testing, but interface stress of the test substructure and calculated substructure is more complex, some factors are ignored, which directly affect the test precision. Han Guang [1] et al, selected reverse bending position of the test substructure as interface, which can eliminate the influence of moment at the interface, they took intermediate position of the experiment substructure as the inflection point, going with a large number of numerical simulation. The result showed that taking the inflection point as interface, accuracy are greatly improved. But the position of the inflection point are influenced by beam column stiffness ratio, not necessarily in the middle position of the layer, so when the beam column stiffness ratio is varied, taking the intermediate position as inflection point might cause be large error.In this paper the inflection point is elected in the elastic layer inflection point, the numerical model is established by using the finite element software Open SEES, Using Matlab as control software to solve the motion equation, and the uniform design method considered the structural layers, beam column stiffness ratio, peak acceleration and other factors, with a large number of numerical simulation. Comparing the results of elastic anti-bending point numerical simulation with the traditional substructure test and intermediate inflection point test, the results proved the accuracy of the proposed elastic inflection point scheme.According to the current standard of designing six story steel frame model and the proposed substructure interface processing scheme, detailed layout of the points, the loading arrangement, and the substructure of the physical tests are also compiled. Finally, The hybrid simulation test of the steel frame model based on the elastic anti-bending point is realized by using the force-displacement hybrid control. The results of physical experiments and numerical simulations show the feasibility of the substructure testing scheme, based on the elastic anti-bending point, which is presented in this paper. At the same time, the six story steel frame model in 310 gal comparison tests of considering and without considering the overturning moment, verified the overturning moment’s influence on the performance of structure can not be ignored. Without considering the interface overturning moment, bounds to change the structure under the earthquake internal force distribution and failure mode, which can not truly reflect the mechanics performance of the structures under the earthquake action.