The Function Of Near-Field Seismic And Seismic Behavior Of Concentrically Braced Steel Chevron-Frames Under Near-Fault Earthquakes

Relevant literature indicates that most of collapsed buildings are located in the near-field areas in recent destructive earthquakes, which is close to epicentral zone. The near-field ground motion shows long-period pulse and velocity and displacement peaks of it are higher than far-field ones, which imposes higher demands on the structure. Relatively speaking, researches and design methods focusing on the characteristics of the far-field and intermediate ground motion are more studied, but the researches of near-field ones related to the seismic codes dealing with problems and design procedures are still incomplete. Therefore, it is necessary to deeply research the near-field ground motion effects.According to Code for Seismic Design of Buildings (GB50011-2010), within 5km, for structures situated on both sides of the seismogenic fault, the near-fault seismic action should multiply intensification coefficient 1.5, with this method, the concentrically braced steel chevron-frames are designed respectively with ten-story, fifteen-story and twenty-story in this paper. A total of 16 near-field ground motion records are selected on the research, and the seismic behavior of the three structures in near-fault ground motion is evaluated in terms of pushover and nonlinear time history analysis.The analytical results indicate that the interstory drift angles of the three structures can meet the requirements of Code for Seismic Design of Buildings under near-field frequent earthquake. But it shows great deformation when dealing with near-field design and rare earthquake which can not meet the requirements of Code. The response of structures are greatly influenced in terms of earthquake peak acceleration amplitude, the level number of structure, the spectral characteristics of near-field ground motions and the different of impulsive effects.