Study On Hysteretic Behavior Of Steel Double-Angle Built-Up T-Chords Based On Special Staggered Truss Under Cyclic Loading

Composite staggered truss framing system has larger bearing capacity and lateral stiffness but its ductility is poor. In order to improve the ductility performance of staggered truss, special staggered truss framing system is proposed. The key to this system is the energy consumption of the middle vierendeel chords, so it is extraordinarily important to choose reasonable middle vierendeel chords. Because of its high bearing capacity, large stiffness, material used fully, torsional performance advantages, composite section gets more and more domestic and foreign scholars’ attention. But so far, the study of composite section is mostly limited to bracing members, and the hysteretic behavior of composite section under reversed cyclic bending gets little research. And there is no corresponding codes or norms for composite bending section. Therefore, it is very necessary to study the hysteretic behavior of steel double-angle built-up members under cyclic loading.The hysteretic behavior of steel double-angle built-up members was studied under cyclic loading through numerical simulation method in this paper. The finite element model was established by using ideal elastic-plastic constitutive model, the Von Mises yield criterion, considering the material nonlinearity and geometrical nonlinearity, ignoring the effect of the initial geometric defects and residual stress. The finite element model was compared with the experiment result of double-channel built-up members which predecessors did to verify the correctness of the modeling and analysis in this paper.In order to study the hysteretic behavior of steel double-angle built-up T-chords under cyclic loading, effect of the parameters, such as fill plate spacing, the lateral support and stiffener spacing, on the hysteretic behavior of specimens was analyzed in this paper from the aspect of the load-displacement curve under monotonic loading, failure pattern, hysteresis curves, skeleton curves, rigidity and strength degradation, ductility coefficient and rotation capacity and energy dissipation. Considering the influence of the three factors, the double-angle specimen which has high hysteretic behavior under the corner of the rules could be got. Finally, by using the result of the analysis on the fill plate spacing, the lateral support and the stiffener spacing, the effect on hysteretic behavior with changing the web thickness and web height of the double-angle members was studied.