Study On The Behavior And Design Method Of Multistory Semirigid Steel Frame

Multistory steel frames are more and more widely used in our country. Conventional analysis and design of steel frames are usually carried out under the assumption that connections joining the beams and columns are either fully rigid or ideally pinned. In fact, as evident from experimental observations, all connections used in current practice possess stiffness which fall between the extreme cases of full rigid and ideally pinned. Because of the absence of calculation theory and designed method for the semirigid connection, it is still calculated and designed as rigid connections in our country, which leads to great waste and anxious hidden trouble. Because of the deffrence between our country and the others, it is important to institute a effective classification system of multistory steel frame, study on the static capability and seismic properties of semirigid multistory steel frame and constitute a calculating and designing method. The researchs include:(1) The effect of joint stiffness on static capability and seismic property of two-dimensional multistory steel frames. Taking the semirigid joint as a spring element, FEM models are set up by ansys to calculate and analyze. The static capability and seismic property of the steel frames with semirigid connections are discussed, and the influence of semirigid connections on the multistory steel frames design is studied in this dissertation.(2) The analysis on the design of multistory steel frames with semirigid end-plate connections. Using the initial connection stiffness and the moment-rotation (M-φ) curve, obtained from both experiment and finite element method,and taking the semirigid end-plate connection as a spring element, a FEM model is set up by ansys to calculate and analyze. The influence of semirigid connections on the multistory steel frames design is studied in this dissertation.(3) Pushover analysis on multistory steel frame with semirigid end-plate conections. In this dissertation a FEM model of a multistory steel frame with semirigid end-plate connections is set up by Sap2000 and modal analysis, spectrum analysis and pushover analysis on the model is calculated. The dynamic properties of the steel frame with semirigid end-plate connections are discussed.(4) Study on classification system of connections for multistory steel frames. In this dissertation, some existing familiar classification systems for beam-to-column connections are presented. And a new classification system is established by parameter analysis.The results above have provided some valuable information for the development of the theory and method on the design of semirigid multistory steel frame.