Nonlinear Simulation And Analysis Of Self-centering Steel Truss Beam

Traditional steel frame systems mainly rely on plastic deformation of main structural members such as beam and column to seismic energy dissipation, and structure will have a relatively large plastic deformation after the earthquake, which makes it difficult for structural repair or even leads to demolition and reconstruction of structure, and finally causes huge economic losses. The raise of new structure system, which owns self-cencering ability, provides a new solution for controlling residual deformation of structure and quick recovery of structure functions.This thesis introduces a seismic design of self-centering steel truss beam, and this member cannot only reduce residual deformation of structure, but also give a solution to special treatment of slab in self-centering steel moment resisting frame. Based on this, this thesis carries on nonlinear simulation and analysis of self-centering steel truss beam by Open Sees, and the results list as follows: results of simulation and analysis are very consistent with theoretical analysis under monotonic loading, which proves the effectiveness of nonlinear simulation model; compared with self-centering steel truss beam with butterfly shaped steel fuse, self-centering steel truss beam with energy dissipation bars owns more stable hysteretic behavior and better performance of energy dissipation; compared with vierendeel special truss beam, self-centering steel truss beam owns greater moment resisting capacity and smaller residual deformation.Meanwhile, this thesis carries on parameter analysis of self-centering steel truss beam, and the parameters involved include area of strand, initial stress of strand, SC value and elastic axial stiffness of fuse. The results list as follows: ① Increase of strands’ area improve the moment resisting capacity of self-centering steel truss beam. ② With too small initial stress, strand cannot provide sufficient self-centering force, and strand with too much initial stress will result in premature yield of strands, which affects the safety of using structure, and the appropriate value of initial stress is 40 percent of ultimate stress. ③ With SC value increases, the moment resisting capacity and energy dissipation of self-centering steel truss beam decreases, but the residual deformation of it also reduces, so determination of SC value must be considered various factors. ④ With the increase of elastic axial stiffness of the fuse, the unloading stiffness of hysteretic curve increases, which leads to more stable hysteretic hysteretic and better performance of energy dissipation. In the case of roof drift ratio up to 4%, truss members and column remains elastic through reasonable parameters design, and energy dissipation bars generate plastic deformation to dissipate energy from earthquake. Steel truss beam come back to original position under the action of the strands after earthquake, and structure will recover from damaged condition just by replacing the damaged buckling-restrained energy dissipation bars.