内置CFRP圆管的方钢管高强混凝土偏压短柱试验

Research on High-Strength Concrete Filled Square Steel Tubular Short Columns with Inner CFRP Circular Tube under Eccentric Load

目的研究内置CFRP圆管的方钢管钢管高强混凝土试件受力特点,解决方钢管混凝土构件在实际工程中的缺陷问题.方法利用PVC管为模管缠制CFRP圆管后,将其内置于方钢管之中并浇筑高强混凝土,待养护期后在500 N压力机上进行偏压试验并对所得试验结果进行计算分析.绘制了荷载-应变等曲线分析了组合材料的协同工作性能;总结偏压荷载作用下组合材料泊松比的变化规律.结果偏心率越大,试件承载力越小.平均偏心率增加7.5%,试件承载力下降20%;含钢率越大试件承载力越大,平均钢管增厚1 mm,试件承载力增加13.6%;CFRP平均增加一层,试件承载力提高约10%.此种新型组合试件同普通钢管混凝土试件相同存在大小偏压,其界限偏心率为0.3.结论CFRP材料强度很高但延性较差.可见该组合试件较好的符合平截面假定.同一偏心率的构件在各级荷载作用下,其中和轴位置基本在同一个微小范围内向加载一侧移动,而且随着偏心率的增大,中和轴位置不断靠近受压一侧.

The force characteristic of high-strength concrete filled square steel tubular short columns with inner CFRP circular tube is researched to solve the problem of practical construction. The CFRP circular tube is made with PVC mould tube. The CFRP tube is put in the square steel tube before concrete cast. The result is analyzed after test which is operated on 500 N punch machine. The load-stain curve is drawn to analyze the cooperative performance of combination of materials and summarize the change rules of Poissong ratio of material. The capacity load decreases with the increasing of eccentricity. The capacity load decrease 20% with the eccentricity increase 7.5 %. And with the increase of 1 mm thickness of steel tube, the capacity load increases 13.6%, with the increase of 1 layer thickness of CFRP tube, the capacity load of specimen increases 10%. The limitation of large and small-eccentricity of this new specimen is 13. 3. The tensility of CFRP mate- rial is weak while strength is high. The changes of specimens are in accordance with the plane cross-section assumption. The neutral axis of specimens under grades load are moved in a small range. The neutral axis is increased with the increase of eccentricity.