露出型钢柱脚强度对低多层规则钢框架抗震性能的影响

Influence of Strength of Exposed Steel Column Foot to Anti-seismic Performance of Steel Frames of Low-layer and Multi-layer

为了研究露出型钢柱脚强度对低多层规则钢框架结构抗震性能的影响,首先定义了不同柱轴向力作用下的露出型钢柱脚屈服弯矩。以柱脚强度系数、层数、跨数及首层剪重比为主要研究参量,建立12个低多层规则钢框架模型。通过静力推覆分析,探讨主要研究参量对各模型各层及柱脚的受力与变形等的影响。分析结果表明:柱脚强度系数越小、首层变形集中、柱脚变形大、锚栓的塑性应变也变大。柱脚强度系数在0.4左右时,锚栓变形支配首层变形。在结构承载能力极限状态时,低层钢框架柱脚均产生轴向压力,受拉压侧柱脚屈服弯矩较锚栓屈服弯矩大;而多层钢框架的受拉侧柱脚将产生轴向拉力,受拉侧柱脚屈服弯矩小于锚栓屈服弯矩。

In order to study influence of strength of exposed steel column foot to anti-seismic performance of steel frames of low-layer and multi-layer,first yield moment of exposed steel column foot under different axial force wes defined. Consider strength coefficient of column foot,the number of layers,the number of across and Shearweight ratio of the first floor to be main parameters,the 12 models of steel frames of low-layer and multi-layer are set up. Through pushover analysis under the static force,the effect of main parameters was investigated to the force and deformation of every layer and foot. The results show that： strength coefficient of column foot is smaller,deformation of the first floor is concentrated,deformation of column foot is large,plastic strain of anchor bolts becomes large. When strength coefficient of column foot is 0. 4,deformation of anchor bolts dominate deformation of the first floor. In ultimate limit states,column foot of low-layer product axial pressure in steel frame,yield moment of column foot on tension and compression side is larger than yield moment of anchor bolts; and column foot of multi-layer product axial tension on tension side,yield moment of column foot on tension side is smaller than yield moment of anchor bolts.