Experimental Study Of Dynamic Performance For Steel Frame With Widen Flange Section

During the earthquake, widespread and unpredicted brittle fractures will be found in welded joints of beam-column of the traditional steel frame due to great stress and deformation concentration. After the earthquake, national and international experts do a lot of experimental research and theoretical analyses and propose a variety of improved beam-column connections. To the widen flange section there are many theory analysis and test and made many research results, and proved that this kind of connection has good energy ability. But to the overall frame with this kind of connection there are little research work. In order to improve the research on dynamic performance of steel frame with widen flange section, we made a pseudo-dynamic test research and a finite element numerical calculation.The main research contents are:Experimental study of dynamic performance for steel frame with widen flange section:The test specimen is a1/2scale model of the steel frame with reinforced connection, the specimen is designed according to construction requirements of United States specification FEMA350, and by loaded in structural laboratory of Qingdao technological University, using pseudo-dynamic test method. Using EL Centro earthquake wave and exert earthquake load of four operating modes separately to the structure, we need to make reasonable adjustments to the velocity peak of the original seismic wave according to requirements of different intensity. Four various seismic acceleration peak are50gal,100gal,200gal,400gal, which correspond to the seismic fortification intensity of six, seven, eight and nine. We obtain the shearing force response of the frame basis as well as each floors’ acceleration responds, the displacement responds in elastic phase, and get the dynamic characteristics of the frame under seismic load.Finite element analysis of dynamic performance for steel frame with widen flange section:In order to verify the test results, using the ANSYS finite element software to analy the performance of the frame in elastic phase, and compared with the test results by the time-history analysis and verify that the test results has a certain reliability, the using of decomposition reaction formation spectrum method proved the time-history analysis is correct. Also we have used ANSYS finite element software for the analysis and comparison of the plastic phase of the steel frame with widen flange section and the steel frame with dog-bone section. By the Comparison, the stress on the whole weakened section of frame with dog-bone section is bigger than steel frame with widen flange section, the lateral displacement of the frame with widen flange section is less than the frame with dog-bone section. It mains that the frame with widen flange section have a larger lateral stiffness and the widen flange section improves the seismic performance of the frame, the load-carrying ability of the frame with widen flange section is better than the frame with dog-bone section. So the widen flange section improves the seismic performance of the frame, and can provide a theoretical and experimental reference for engineering applications which uses widen flange section.