钢筋增强ECC-钢管混凝土组合柱抗震性能试验及其数值模拟

为研究钢筋增强ECC-钢管混凝土组合柱的抗震性能,完成了7根钢筋增强ECC-钢管混凝土组合柱和4根钢管混凝土叠合柱的低周往复加载试验。试验结果表明:钢筋增强ECC-钢管混凝土组合柱在低周往复荷载下均具有较好的延性,滞回曲线饱满,未出现明显的"捏缩"效应,表明ECC材料与核心钢管混凝土具有较好的协同变形能力和组合作用。相比之下,钢管混凝土叠合柱试件在低周往复荷载下出现明显的外层混凝土剥离现象,滞回曲线捏拢现象较为明显。通过累积耗能对比分析可知,钢筋增强ECC-钢管混凝土组合柱的累积耗能约为钢管混凝土叠合柱的2倍,表明钢筋增强ECC-钢管混凝土组合柱具有更好的抗震性能,适用于抗震设防烈度较高地区。此外,基于有限元软件ABAQUS对钢筋增强ECC-钢管混凝土组合柱的滞回性能进行了模拟,将有限元分析结果与试验结果对比发现,二者吻合较好,表明采用该有限元模型可以较为准确地研究该类组合柱的抗震性能。最后,基于有限元模型探讨了不同参数对组合柱受力性能的影响。

Experimental and analytical research on seismic behavior of ECC-encased concrete-filled steel tubular columns

In order to investigate the seismic behavior of ECC-encased concrete-filled steel tubular (hereafter known as CFST) columns, seven ECC encased CFST columns as well as four concrete-encased CFST columns were tested under axial force and lateral reversed low cyclic loads. According to the test results, ECC-encased CFST columns exhibit favorable ductility and all the hysteresis loops are fusiform with no visible pinching effect, indicating a good composite effect between inner CFST and outer ECC components. By contrast, significant outer concrete spalling is observed for concrete-encased CFST columns under cyclic loads. A clear pinching effect of hysteresis loops is also observed for each concrete-encased CFST column. The cumulative energy dissipation of ECC-encased CFST column is about twice as much as that of concrete-encased CFST column with the same geometry, indicating that the proposed composite columns have more favorable seismic behavior as well as the ECC-encased CFST columns are suitable to be applied in the region with high degree of fortification intensity. The hysteretic behaviors of ECC-encased CFST columns were also numerically simulated and investigated by finite element analysis software ABAQUS. The experimental results and the numerical simulating results were compared to validate the proposed FEA model. It is concluded that the FEA model proposed in this paper is accurate in simulating the seismic behavior of ECC-encased CFST columns. Parameter study was also conducted to examine the effect of different parameters on the mechanical behaviors of the ECC-encased CFST columns.