冻融循环-酸雨锈蚀交替作用后圆钢管混凝土轴压短柱力学性能分析

基于材料强度折减及钢管壁厚折减的方法,对冻融循环-酸雨锈蚀交替作用后圆钢管混凝土轴压力学性能采用有限元法进行了研究。基于合理的有限元分析模型,对冻融循环-酸雨锈蚀交替作用后圆钢管混凝土柱的破坏模态、轴向荷载-位移关系、钢管与混凝土相互作用进行了分析,研究了含钢率、截面尺寸、钢管屈服强度、混凝土轴心抗压强度以及冻融循环-酸雨交替次数对试件轴压极限承载力的影响。结果表明:有限元模拟结果与试验结果吻合良好,验证了模型的有效性; 冻融循环-酸雨锈蚀交替作用后轴压圆钢管混凝土短柱的破坏模态与普通试件相似,轴向荷载-位移曲线变化趋势一致,试件均为塑性破坏; 圆钢管混凝土轴压短柱随冻融循环-酸雨锈蚀交替次数的增加,材料性能劣化严重,外钢管对核心混凝土约束作用减弱,试件极限承载力明显下降。

Analysis on axial compressive mechanical behavior of circular concrete-filled steel tube stub column under alternation of freeze-thaw cycle and acid rain corrosion

Based on the methods of material strength reduction and steel tube thickness reduction, the axial compressive mechanical behavior of circular concrete-filled steel tube(CFST)stub columns under the alternation of freeze-thaw cycle and acid rain corrosion were studied by finite element method. Based on the reasonable finite element analysis model, the failure mode, axial load-displacement relationship and the interaction between the steel tube and concrete of circular CFST stub columns under the alternation of freeze-thaw cycle and acid rain corrosion were analyzed. The effects of steel ratio, section size, yield strength of steel tube, axial compressive strength of concrete and alternating time of freeze-thaw cycle and acid rain on the axial compressive ultimate bearing capacity were studied. The results show that the finite element simulation results are in good agreement with the experimental results, which verifies the validity of the model. The failure mode of axially loaded circular CFST stub column under the alternating action of freeze-thaw cycle and acid rain corrosion is similar to that of ordinary specimen. The variation trends of the axial load-displacement curves are consistent, and all specimens are plastic failure. With the increase of alternating time of freeze-thaw cycle and acid rain corrosion, the material properties deteriorate seriously and the restraint effect of steel tube on core concrete weakens, which causes the ultimate bearing capacity of specimen decreases significantly.