Study of an Optimum Design Method for Links

Abstract

Under severe earthquakes, eccentrically braced frames might experience large inelastic deformations, and the inelastic action is restricted primarily to the ductile links. In order to study the reasonable design method for links, seventy analyses of links are conducted to investigate the effect of different flange width-thickness ratio and length, fifty links are also designed to study the influence of stiffeners spacing, stiffeners thickness and placing on side(s), and thirty-six links are designed to consider the effect of axial loads, which are all based on the material properties of Q235 steel. The accuracy of finite element models is verified using the experimental data during cyclic loading. Numerical analysis results show that the flange width-thickness ratio of short and long links can be relaxed to 10√235/fy , and stiffeners can only be placed on one side. However, the flange width-thickness ratio of intermediate links is limited to 8√235/fy , and stiffeners should be placed on both sides due to the unstable behavior. Stiffener thickness has no significant influence on the performance of links with varying length. Unlike short links, intermediate and long links are susceptible to the axial forces. Then an optimum design method is proposed by analyzing the main influencing factors, so links can have good ductility and stiffness at high load levels.