玻璃纤维增强聚合物复合材料约束壁式钢管混凝土短柱轴压性能试验

Experiment on axial compression performance of glass fiber reinforced polymer-walled concrete-filled steel tube columns

为研究玻璃纤维增强聚合物复合材料(GFRP)约束壁式钢管混凝土矩形短柱的轴压力学性能,对1组无GFRP约束试件和2组GFRP约束试件进行静力轴压试验;根据试验结果提出壁式柱的强弱约束模型,并基于双剪统一强度理论建立GFRP约束壁式钢管混凝土柱的轴压承载力计算公式;最后建立有限元模型,将计算结果与试验对比,并进行参数化分析,研究钢材屈服强度和混凝土强度对新型壁式钢管混凝土柱轴压性能的影响。结果表明:壁式钢管混凝土柱最终因柱中混凝土压碎、钢管屈曲、试件变形过大而失效;钢材在试件第二线性段起点处开始屈服,钢材强度得到充分发挥,GFRP能有效提高构件峰值承载力,但延性有所下降;理论公式计算结果与试验值吻合较好;混凝土强度及钢材屈服强度均能有效提高承载能力,且钢材屈服强度对承载力的影响明显大于混凝土强度的影响。

In order to study the axial compression performance of glass fiber reinforced polymer(GFRP)-walled concrete-filled steel tube columns, the static axial compression tests were conducted on a group of non-GFRP constrained specimens and two groups of GFRP constrained specimens. According to the test results, a strong and weak constraint model of the wall column was proposed. Based on the twin-shear unified strength theory, the formula was established to calculate the axial compression bearing capacity of the GFRP-walled concrete-filled steel tube columns. Finally, the theoretical results, obtained through the establishment of the finite element model, were compared with the experimental results. And a parametric analysis was used to study the effect of the yield strength of steel and the strength of concrete on the axial compression performance of the new type wall-filled concrete-filled steel tube columns. The results show that the wall-filled concrete-filled steel tube columns eventually fail due to crushing of the concrete, buckling of the steel tube and excessive deformation of the specimens. At the beginning of the second linear section of the specimen, the steel begins to yield and its strength is fully exerted, which demonstrates that GFRP can effectively improve the peak load of the member, however, the ductility has decreased. The results of the theoretical formula are in agreement with the experimental results. The bearing capacity can be improved by increasing the strength of concrete and the yield strength of the steel. Compared with the strength of concrete, the yield strength of steel bars has a greater influence on the bearing capacity.