外套钢管加固的钢管混凝土柱轴压力学性能研究

Axial Compression Performance and Mechanical Property of CFST Columns Reinforced with Outer Steel Tubes

既有圆和方钢管混凝土柱性能不足时,采用外套钢管可简单高效地对其进行加固。利用ABAQUS分别建立外套钢管加固的圆和方钢管混凝土柱有限元模型并与试验进行验证,分析端部长度、夹层材料厚度和强度、钢管径厚比和屈服强度以及核心混凝土强度等因素对外套钢管加固的钢管混凝土柱轴压性能的影响。结果表明:直径不小于300 mm的钢管混凝土加固后,其端部长度不超过60 mm时无需采取端部加强措施;较小的夹层材料厚度和较高的夹层材料强度有利于保证外套钢管加固效果;较小的外套钢管径厚比、较大的内层钢管径厚比和较低的核心混凝土强度均可以提升外套钢管的加固效果。基于叠加法,分别提出外套钢管加固的圆和方钢管混凝土柱轴压承载力计算方法,其预测结果与有限元及试验结果吻合良好。

Deficient circular and square concrete-filled steel tube(CFST) columns can be reinforced with outer steel tubes effectively. In this paper, ABAQUS was utilized to establish finite element models for the circular and square CFST columns reinforced with outer steel tubes, respectively, and the models were validated through tests. Furthermore, the effects of the column end length, the thickness and strength of sandwich materials, the ratio of diameter and thickness and the yield strength of steel tubes, and the core concrete strength on the axial compression performance of the CFST columns reinforced with outer steel tubes were analyzed. The results show that no extra strengthening configuration is needed for the column with the diameter greater than 300 mm if the column end length is less than 60 mm. The low thickness and high strength of the sandwich materials can guarantee the reinforcement effect of the outer steel tubes. In addition, a small ratio of the diameter and thickness of the outer steel tubes, large ratio of the diameter and thickness of inner steel tubes, and low core concrete strength can improve the reinforcement effect of the outer steel tubes. According to the superposition method, methods for calculating the axial compression bearing capacity of the circular and square CFST columns reinforced with the outer steel tubes were proposed, and the prediction results are in good agreement with the test and finite element results.