Research On Practical Seismic Design Method Of RC Column-steel Beam With Semi-rigid Connection

Reinforced concrete and steel beam with semi-rigid connection is a new prefabricated assembly structure,which exerts advantages of concrete and steel well.The prefabricated construction method can improve the construction efficiency and industrialization level.Semi-rigid connections posses better ductility,energy dissipation capacity and recoverability.These advantages show semi-rigid RCS structure is suitable as an earthquake-resistant system located in seismic regions.The relevant investigation of semi-rigid RCS structure is vacancy in our relative structural code.Because of the semi-rigid connection,nonlinear analysis is used to design structures which is difficult for civil engineers to master and design practically.So the research on practical seismic design method of semi-rigid RCS structure has important value on its theory and practice.This paper investigates practical seismic design method of semi-rigid RCS structure based on test and theory methods,and the main work and conclusions are as follows:(1)Mechanical behavior of RCS connection: Based on tests and connection characteristics,formulas are given with regards to initial rotation stiffness and ultimate moment capacity.The theoretical model for the moment-relative rotation relationship of the connection is proposed.Good agreement is observed between analytical and test results.At last,the design method of RCS connection is proposed.(2)Structural analysis of semi-rigid RCS frame: The link element is used to simulate the semi-rigid connection by SAP2000.Validity of the modeling method is verified through comparison between the simulation and test results.In order to research the mechanical behavior and seismic performance of semi-rigid RCS frame,two analytical models of semi-rigid RCS and common frames are established by SAP2000.Analysis results show that the semi-rigid connection weakens structural stiffness,increases the natural vibration period of the structure and reduces seismic action while the deformation and lateral displacement of the structure will increase accordingly.Beyond story drift limit,It's possible for semi-rigid RCS frame to save materials and realize the economic efficiency when the semi-rigid connections are designed reasonably.(3)Practical seismic design method of semi-rigid RCS structure is proposed.Theseismic action at elastic stage and ultimate stageis connected by overstrength and ductility reduction factors.The overstrength factors which are used to calculate the yield base shear under major earthquake are suggested according to a great deal of analysis.The calculated yield base shear can provide the bearing capacity requirements of structures under major earthquake.In order to make sure the design purposes,the plastic design method and capacity design method are used to design members on the basis of the yield base shear and expected yield mechanism.(4)Example design and performance evaluation: The proposed method is applied to three different examples.The structures designed have better seismic performance and the results meet the expected purposes which verifies the effectiveness and rationality of the proposed practical design method.