The Structural Influencing Coefficient Of Multi-story Steel Frames

Large experimental research and earthquake disaster analysis indicate that building structure can enter elastic-plasticity to consume the earthquake energy and diminish the earthquake effect in strong motion earthquake. In order to simplify seismic design, seismic code of partial nation present structural influencing coefficient (or seismic response modified coefficient) to reduce the elastic response spectrum to obtain the design earthquake effect of various structure systems and then calculating the seismic response of structure according to elasticity. The structural influencing coefficient is the important factor of determining design earthquake action, which is based on the condition-based seismic design. The security and economy of structure design lie on the value of structural influencing coefficient.Foreign codes about the definition and value of structural influencing coefficient isn't the same. Comparing the foreign seismic code with our country', it is unreasonable that the single structural influencing coefficient is nowadays adopted by currently Code for seismic design of buildings in all structural systems built by different materials in our country. For multi-story steel frames, the earthquake action value of our country is higher and the good ductility and energy-dissipating capability are not utilized sufficiently, which cause steel materials wasted to large extend.In this paper nine examples, which are designed owning to currently Code(GB50011-2001) for seismic design of buildings of my country, are used to analyze the structure earthquake response under the horizontal seismic load by Timehistory analytical method. The corresponding structural influencing coefficient is analyzed taking into account the factors changing, such as level number, span length, span number. The result indicates earthquake actions of these steel frames designed according to the Code (GB50011-2001) are higher, then it is suggested to reduce earthquake actions properly.At last,some reasonable design suggestions are presented for the seismic design of multi-story steel frames.