Globe Elastic-Plastic Stability Analysis Of One-Story Plane-Steel Frames

Steel frames are used widely abroad and applied greatly in our country withcomprehensive such as light weight, low project expense, more effective-used area ofbuildings, less construction stage and high capital mileage etc. Losing stability is always oneimportant factor of damage of steel frames. Stability analysis is one important part in thecourse of steel frames design. Especially nowadays, structures trend to light-thin modelbecause of the development of design theory and material property. It is a highlight that steelstructures total stability is calculated. Stability design method of frame column currently ineffect is based on the second-order elastic analysis of bias pressure staff and is expressed byamplifying one-order moment. But, losing stability of frames with side displacement occurswhen the elastic-plasticity of stuff develops to some level. The in-plane stability test on theinelastic steel frames proves that the second-order inelastic analysis is a better method ofdetermining the ultimate capacity of frames. In this paper, Transfer Matrix Method is introduced to study total elastic-plastic stability ofsteel frames. Making use of elastic-plastic numerical model, Beam-element ,column-elementtransfer matrix that indicate elastic-plastic state parameters of two ends of bars and transfermatrix that indicates internal force and displacement variety off every braces are derived inthis paper. The total transfer matrix that solves bucking load of frames is obtained. The valuesof top-story horizontal displacement and loads can be obtained by use of the total transfermatrix. So, the ultimate load can be obtained. The effects on steel frames stability of initialflexure ,initial bias ,residual stress and P-Δ effect that is brought by the displacement offrames are included in the course of stability analysis of steel frames by transfer matrixmethod . By the idea, the corresponding computation program is written with MATLABwhose function in dealing with matrix is very big. The analysis and comparison of someexamples indicates that the method the text suggested is effective in studying totalelastic-plastic stability of one-story plane-steel frames, with high degree of accuracy, clearmechanical concept and convenient programming.