Energy-based design method for special concentrically braced frames considering low-cycle fatigue damage of braces

Abstract

Energy-based design methods have been widely used to evaluate structural performance in last few decades. However, energy-based design methods of SCBF proposed by previous researches did not fully consider the low-cycle fatigue damage of braces. To study energy-based design method of SCBF considering the effect of low-cycle fatigue damage of braces, inelastic dynamic time history analysis of six SCBF models is performed and experimental data is evaluated in this paper. Energy input spectrum of SCBF is modified and energy demand of braces are proposed by dynamic time history analysis. Energy dissipation capacity of braces based on low-cycle fatigue damage of braces is set up through the results of tests on braces and braced frames. A practical energy-based design method of SCBF is proposed by obeying the principle that energy demands are smaller than energy dissipation capacity of braces. An integral design process of energy-based design method of SCBF is shown in this paper by a designed SCBF example. The configuration detailing of braces meeting the regulations of AISC 341 is relatively stricter compared with the security domain of proposed energy-based design method. The configuration detailing of braces is not only related to ductility of the structure, but also intensity of design ground motion according to the energy-based design method proposed by this paper.