Finite Element Analysis Of Flange Slenderness Ratio, Overstrength And Failure Models Of Links In Eccentrically Braced Frames

The design intent for a steel eccentrically braced frame is that inelastic action under strong earthquake motion is restricted primarily to the links, which are designed to provide adequate display and ductility.The theoretical basis of today's building codes in the design of eccentrically braced frames method are mostly from trials done abroad. However, most of the experiments are based on wide-flange of ASTM A36, which is equivalent to the domestic steel Q235.The relevant experiments done in domestic are also based on the Q235 steel. The current high-strength steels because of its advantages are widely used in building structures. Many wide-flange sections are made of Q345 steel. This raises a question:The flange slenderness ratio of many rolled wide-flange shape can not meet the specification requirements, which eliminate a number of rolled wide-flange shape from use in EBFS. At the same time, the flange slenderness ratio of the value in the specification is based on the classical theory, which neglect many factors. Therefore the flange slenderness ratio should be a reasonable value.Building models using ANSYS program and control procedures for the previous tests to verify the correctness in the article. And then design the specimens. This paper applies unidirectional load and cyclic load on the finite element models respectively. This paper studies the inelastic rotation, failure model and overstrength factor which the link beams reach after the relaxation of the flange slenderness ratio. By changing the way of settings stiffener to improve the hysteretic performance of the bending shear-type link beams, and influences of changing the flange width-thickness ratio. The main conclusions are:The flange slenderness ratio of shear yielding links and flexural links can relax from (?) to (?).By setting relatively dense stiffeners at the ends of the link beam can significantly improve the hysteretic performance of the bending shear-type link beams. The paper proposes the value method of increasing coefficient should be in accordance with the yield type. Finally it summarizes the main failure modes of the three different yield types.