设置带削弱段连接板的钢柱脚抗震性能有限元研究

在非线性分析平台OpenSEEs上，根据设置带削弱段连接板的钢柱脚构造形式及受力特征，以模拟关键部件的力学特征为主，建立可反映柱脚节点在弯矩与轴向力耦合作用下受力性能的简化模型，并通过试验数据验证简化模型的有效性。在此基础上，以连接板削弱段的宽厚比和横截面面积，以及轴压比为参数，建立了9个有限元模型，研究柱脚节点的抗震性能和滞回特征。结果表明：柱脚节点的受弯承载力与连接板削弱段宽厚比无关；当连接板削弱段横截面面积扩大至原来的4倍时，受弯承载力提高至原来的2.3倍；当轴压比由0.2(轴压)变为-0.2(轴拉)时，受弯承载力降低了66.9%。柱脚节点的耗能能力受轴压比的影响较小；当连接板削弱段宽厚比减小为原来的一半时，耗能能力提高了23.5%；当连接板削弱段横截面面积增加为原来的4倍时，耗能能力提高至原来的4.2倍；柱脚节点的自复位能力与连接板削弱段宽厚比无关，与连接板削弱段横截面面积成反比，而与轴压比成正比。综上可知，在恒定的轴压比下，可通过减小连接板削弱段的宽厚比来提高柱脚节点的耗能能力，通过调整连接板削弱段的横截面面积平衡柱脚节点的耗能能力与自复位能力。

Finite element study on seismic performance of steel column base with weakened fuses

A simplified computational model of the steel column footing with weakened fuses was developed by using OpenSEES. The proposed model was related to the configuration of the column footing, focusing on reproducing the mechanical behavior of the key components. The coupling effect of the moment and axial load applied on the column footing could be successfully simulated by adopting the proposed model. The validity of the proposed model was verified by test results. To investigate the effects of the width-thickness ratio and cross-sectional area of the fuse weakened part, and the axial load ratio on the seismic performance of the column footing, a parametric study was conducted with nine computational models. The results show that the moment capacity is not related to the width-to-thickness ratio. The moment capacity increases to 2.3 times as the cross-sectional area increases to four times. The moment capacity decreases by 66.9% as the axial load ratio changes from 0.2 (compression) to -0.2 (tension). The energy dissipation capacity is less sensitive to the axial load ratio, while it can be improved by 23.5% and improved to 4.2 times as the width-thickness ratio reduced by 50% or the cross-sectional area increases to four times, respectively. The self-centering capacity is not related to the width-to-thickness ratio, while it is inversely proportional to the cross-sectional area and is proportional to the axial load ratio. In general, at fixed axial compression ratio, it is suggested that the energy dissipation capacity can be improved by reducing the width-thickness ratio, while the balance between the energy dissipation and self-centering capacity can be found by adjusting the cross-sectional area.