圆钢管轻集料混凝土抗弯刚度计算方法的探讨

Calculations of flexural stiffness of lightweight aggregate concrete filled circular steel tube

通过对21个钢管轻集料混凝土试件的纯弯试验研究,分析了钢管轻集料混凝土抗弯刚度的影响因素,并将钢管轻集料混凝土试件的初始抗弯刚度和使用阶段抗弯刚度与国内外相关规范AIJ,BS5400,EC4,AISC-LRFD和DBJ13-51的计算结果进行了对比和分析,对钢管轻集料混凝土抗弯刚度的计算方法进行了探讨。试验结果表明,在其他参数相同的条件下,内填轻集料混凝土的强度对试件抗弯刚度影响很小,随着钢管壁厚的增加,试件抗弯刚度明显提高;有关抗弯刚度计算分析对比结果表明,除AIJ(1997)的计算结果与初始抗弯刚度以及使用阶段抗弯刚度试验结果吻合较好外,其余规范的计算结果均偏大。在计算钢管轻集料混凝土抗弯刚度时,建议采用日本AIJ(1997)给出的钢管普通混凝土抗弯刚度计算公式。

21 lightweight aggregate concrete filled steel tubes （LACFST）subjected to pure bending were carried out. Influencing factors of the flexural stiffness of LACFST were analyzed. The initial flexural stiffness and the service-level flexural stiffness of the specimens were compared with design codes both at home and abroad, such as All, BS5400, EC4, AISC-LRFD and DBJ13-51. The calculation method of the flexural stiffness of LACFST was discussed. The results show that the strength of lightweight aggregate concrete has a little effect on the flexural stiffness, but with the thickness of steel tube increasing, the flexural stiffness are enhanced significantly. The test results were compared with the results calculated by the formulas, it is showed that the results calculated by the formula of All are in good agreement with the test results of initial flexural stiffness and the service-level flexural stiffness, but the results calculated by the formula of others are greater than the test results. The formula of All is recommended in the calculation of flexural stiffness of LACFST.