Second-order Analysis Design Method For Flush End-plate Semi-rigid Connection Steel Frames

Steel structure for residential housing system is the development direction in future residential industrialization road. Due to its convenience in connection and suitable for industrialized produc tion, low cost and excellent seism ic performance,semi-rigid connection steel fram e structure is very suitab le for steel structure residence. But until now, the se mi-rigid connected steel frame structure used in practical engineering is rare. The main reason is that rela ted analysis and design methods is com plex. So im proving the existing design theory for semi-rigid connected steel frame structure has a strong practical value and important theoretical significance.This paper based on the technical specification for steel structures with end-plate semi-rigid connection’s calculation principle, proposes the m odified tensile strength reduction f actor of steel bar to consider the negative m oment zone composite joints on both sides of the unbalanced reinforced force.Using MATLAB, combined with experim ental data, propose different the modified tensile strength reduction factor of steel bar to consumm ate the m ethod for calculating the mom ent-rotation curve relationship of sem i-rigid connections.Using MATLAB software and finite element analysis software SAP2000 calculate and anal ysis different secant s tiffness and theoretical calculation of the m oment-rotation curve relationship which are com pared and elected to apply to the actual project’s secant stiffness.On the basis of the above conclusions,the second-order elastic an alysis of se mi-rigid steel fram e is calculated by SAP2000,and analysis the second-order effect on the lateral displacement and internal force of semi-rigid steel frame.The following are the main contents in detail:Firstly, This paper based on the technical specifica tion for steel structures with end-plate sem i-rigid connection’s calculation principle,combined with experimental data, and proposed the tensile strength reduction factor of steel bar of the side joint and the m iddle joint under vertical and horizontal loads. And the related parameters’ study are studied based on the above conclusions.Secondly,This paper established six laye rs,nine layers and twelve layers framework model,analysis the error value about the secant stiffness and precise moment-rotation relationship to sim plify the m oment-rotation nonlinear relationship for practical engineering.Thirdly,the depth-span ration is 1.5,2 and 3 of th e semi-rigid steel frame analysis model were establ ished and study the second-o rder’s effect of rigid frame and different connection stiffness of semi-rigid frame.Fourthly,this paper gives sem i-rigid connection frame design process,and analysis the difference between the second-order elastic calculation method and the traditional calculation length coefficient method to frame design.