西安建筑科技大学学报(自然科学版)

为研究中空夹层钢管超高强混凝土受压构件火灾后的力学性能,开展了4个火灾后中空夹层圆钢管超高强混凝土短柱轴压试验,夹层超高强混凝土的抗压强度超过160 MPa,通过试验结果可以看出,试件的荷载-位移曲线可以分为四个阶段:弹性阶段、弹塑性阶段、塑性阶段和下降阶段.结果表明:即使试件已经历前期耐火极限试验,该组合构件仍有较好的剩余承载能力和延性性能.剥去试件部分外钢管,对夹层超高强混凝土的碎裂、外钢管的凸曲及内钢管的凹曲破坏机理进行了阐释.建立中空夹层圆钢管超高强混凝土柱有限元计算模型,考虑钢管壁与夹层混凝土之间的接触效应,并根据材性试验对已有的钢材及混凝土火灾后的材料本构关系模型进行修正,将修正后的材料本构关系模型应用到试件数值模拟中,最终计算得到试件有限元模型的破坏模式与试验后的破坏模式近似,荷载-位移曲线计算结果与试验结果吻合较好,试件经历的最高温度对剩余承载力影响显著.

In order to further study the mechanical properties of ultra-high strength concrete-filled double-skin circular steel tubular column after fire, axial compression test of four short circular steel tubular column specimens was carried out with sandwich concrete strength of more than 160 MPa. It can be seen from the test results that the load-displacement curve of the component can be divided into four stages: elastic stage, elastic-plastic stage, plastic strengthening stage and descending stage. This shows that the composite component has better residual bearing capacity and ductility performance even if it has undergone previous fire resistance test. By stripping the outer steel tube of the specimen, the fracture mechanism of the interlayer ultra-high strength concrete, the convex bend of the outer steel tube and the concave bend of the inner steel tube are explained. The finite element model of ultra-high strength concrete-filled double-skin circular steel tubular column is established, and considering the friction effect between steel tube wall and sandwich concrete, the material constitutive relation model of steel tube and concrete after fire is modified according to the material property test. Then, the modified material constitutive relation model is applied to the numerical simulation of specimens. The failure mode of the finite element model of the specimen is approximate to the failure mode after the test, and the calculated results of the load-displacement curve are in good agreement with the test results. The maximum temperature experienced by the specimen has a great effect on the residual capacity.

引言
1 试件制作及试验过程
2 试验结果及分析
3 有限元模型分析
4 结论

图1 试件制作及试验布置<br/>Fig.1 Fabrication of specimen and experiment arrangement

图1 试件制作及试验布置
Fig.1 Fabrication of specimen and experiment arrangement

表1 长柱试件耐火极限试验相关参数[10]<br/>Tab.1 Parameters of specimens in fire resistance experiment

表1 长柱试件耐火极限试验相关参数[10]
Tab.1 Parameters of specimens in fire resistance experiment

表2 火灾后轴压短柱试件相关参数<br/>Tab.2 Relevant parameters of specimens after fire

表2 火灾后轴压短柱试件相关参数
Tab.2 Relevant parameters of specimens after fire

图2 试件N-ε曲线<br/>Fig.2 N-ε curve of specimens

图2 试件N-ε曲线
Fig.2 N-ε curve of specimens

图3 试件N-Δ曲线<br/>Fig.3 N-Δ curve of specimens

图3 试件N-Δ曲线
Fig.3 N-Δ curve of specimens

图4 典型试件N-Δ曲线<br/>Fig.4 N-Δ curve of typical specimen

图4 典型试件N-Δ曲线
Fig.4 N-Δ curve of typical specimen

图5 试件破坏形态<br/>Fig.5 Failure mode of specimens

图5 试件破坏形态
Fig.5 Failure mode of specimens

图6 典型试件内、外破坏模式<br/>Fig.6 Internal and external failure modes of typical specimens

图6 典型试件内、外破坏模式
Fig.6 Internal and external failure modes of typical specimens

图7 试件网格划分
Fig.7 Specimen meshing

图8 有限元分析与试验对比<br/>Fig.8 Comparison between finite element analysis and experiment

图8 有限元分析与试验对比
Fig.8 Comparison between finite element analysis and experiment

图9 N-Δ曲线试验值与计算值对比<br/>Fig.9 Comparison of experimental and calculated values of N-Δ curve

图9 N-Δ曲线试验值与计算值对比
Fig.9 Comparison of experimental and calculated values of N-Δ curve

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备注

引言

1 试件制作及试验过程

2 试验结果及分析

3 有限元模型分析

4 结论

期刊信息