模拟酸雨环境下圆钢管再生混凝土纯弯试验研究

Experimental study of recycled concrete-filled circle steel tubes subjected to pure bending under the environment of acid rain

对模拟酸雨腐蚀后的8根圆钢管混凝土试件进行纯弯试验研究,考虑混凝土骨料类型和腐蚀率2个变化参数,研究变化参数对试件纯弯力学性能的影响;在此基础上,利用有限元分析软件,分别采用壁厚折减和材性折减两种方式来考虑酸雨腐蚀对试件纯弯力学性能的影响。研究结果表明:整体上所有试件均呈现出跨中弯曲变形,可知酸雨腐蚀对试件的破坏形态无明显影响;且所有试件直至试验结束,其跨中弯矩-挠度曲线均未出现下降段,表明在该腐蚀范围内,圆钢管混凝土试件在纯弯受力过程中仍具有良好的变形能力和延性;在相同腐蚀率下,圆钢管再生混凝土与圆钢管普通混凝土的极限承载力平均比值为0.94,表明圆钢管再生混凝土的极限承载力略低于圆钢管普通混凝土;随着腐蚀程度的加深,试件的刚度和极限承载力有明显降低;对比有限元计算结果与试验结果,验证了有限元建模方法的正确性及分别采用壁厚折减和材性折减来考虑酸雨环境对纯弯试件腐蚀影响的可行性。

Pure bending tests on 8 circle concrete filled steel tubes(CFST) subjected acid rain corrosion were carried out. Two parameters of concrete aggregate type and corrosion rate are considered to study the influences of the variation parameters on the pure bending mechanical properties of the specimens. Based on this, the finite element analysis software(FEA) is used to study the effects of acid rain corrosion on the pure bending mechanical properties of the specimen by adopting the methods of wall thickness reduction and material reduction respectively. The results show that, acid rain does not change the failure mode of pure bending specimens of RACFST. All the curves of the bending moments versus mid-span deflection of specimens do not show descending section until the end of the experiment, it shows that in the scope of the corrosion, the CFST still has good deformation capacity and ductility. Under the same corrosion rate, the average ratio of the ultimate bearing capacity of RACFST to CFST is 0.94, which indicates that the ultimate bearing capacity of RACFST is slightly lower than that of CFST. With the increasing of corrosion degree, the stiffness and the ultimate bearing capacity of the specimen decrease obviously. By comparison of the finite element calculation results with the test results, the correctness of the finite element modeling method is verified. It shows that the wall thickness reduction and material reduction respectively reflect the effects of acid rain environment on the pure bending mechanical properties of the circle RACFST.