Seismic Effect And Capacity Design Approach Of Non-Energy-Cosuming Components In Eccentrically Braced Frame

The eccentrically braced steel frame structure dissipates the seismic energy through the stable and controllable plastic deformation of the links;therefore,other components basically maintain elastic behavior.This kind of structure has advantages over the centrically braced steel frame structure and the moment frame structure,not only having a large rigidity but also having a good energy dissipation capacity under the rare earthquake.Therefore it has great advantages as a seismic system.At present,the current eccentrically braced steel frame design codes in various countries are based on capacity design methods.There are also series of problems in how to propose a linear design method of column which considers the above links which develop the maximum shear force at different time.In order to solve these problems and to propose a more effective eccentrically braced steel frame capacity design method,this paper analyzes the seismic respond of the eccentrically braced steel frame structures.The specific research contents are as follows:(1)Introduce the capacity design methods of the eccentrically braced steel frame in China and the United States and compare the differences and the similarities between the two.According to the Chinese Codes,the eccentrically braced steel frame structure with different length of links,different seismic precautionary intensity(8 degree and 9 degree),and different height(4,8,16 stories)are designed.(2)Use ABAQUS software to establish a multi-element type finite element model of the designed structure and perform nonlinear time-history analysis under the selected seismic records;Compare the differences between the design internal force of nonenergy-consuming components and the internal force under the effect of a rare earthquake.(3)Based on the rare earthquake effect on the non-energy-consuming components,the current design methods in China and the United States are evaluated.Propose a design equation for the axial demand of steel columns to guide the design of the eccentrically braced steel frame's columns.The influence of the bending moment effect on the steel column is analyzed.The influence of the axial force effect of the beam outside of the link and the bending moment of the brace which were neglected in the Chinese specification on the overall structure is explored.The corresponding design suggestions are given.