SCFST柱框架-支撑结构恢复力模型

Restoring force model of SCFST column braced frame

通过对SCFST柱框架-支撑结构进行拟静力性能研究发现,支撑、梁、柱依次发生破坏,结构破坏机制合理,滞回曲线呈梭形,无捏拢现象,耗能能力良好,骨架曲线的下降过程较为平缓,延性较好,结构在整体上表现出较好的抗震性能,有限元数值模拟与试验结果符合程度较高,验证了有限元模型的正确性。主要研究支撑两边柱的轴压比、单肢柱不同组合截面形式和框架-支撑结构中支撑钢管的刚度等因素,基于大量的有限元数值模型对其进行分析,得到了SCFST柱框架-支撑抗侧力结构的恢复力模型。运用回归分析方法建立结构的三折线骨架模型,明确了SCFST柱框架-支撑结构的滞回和退化规律,建立了此体系框架-支撑结构简化的滞回模型,并与试验结果进行对比分析,二者骨架曲线基本一致,滞回环形状均呈近似的平行四边形,吻合度较高。

Special-shaped column composed of concrete-filled square steel tubes(the SCFST column)braced frame has broad prospects of applications in high-rise steel structure residence for the reason that it represents considerable lateral stiffness,good seismic performance and outstanding architecture effect.Quasi-static tests were conducted to explore the seismic behavior mechanism,and beams and columns were destroyed in turn.The hysteretic curves of the structure were diamond-shaped with no pinch phenomenon,which illustrated that the structure performed well in energy dissipation.The structure had good ductility and seismic behavior in that the skeleton curve declined slowly.The finite element(FE)numerical simulation agreed well with the experimental result,verifying the correctness of the FE model.The restoring force model of the SCFST column-steel beam braced frame took axial compression ratio,the section of the column and the stiffness of the brace as main research factors.By linear regression analysis,the trilinear skeleton model was established which showed the hysteretic behavior and stiffness degradation of the SCFST column braced frame.As seen by from the comparison of the results of the model with those of the experiment,the skeleton curves of the model and the experiment were nearly the same,both of the hysteretic curves were in the shape of a parallelogram,and the anastomosis degree was high.In conclusions the restoring force model is an effective way to simulate the behavior of the frame and it canpresent the load displacement curve of the SCFST column braced frame under low reversed cyclic loading.