圆钢管混凝土轴压短柱在长期荷载-氯盐腐蚀耦合作用下的试验研究

Experimental study on axially compressed circular concrete-filled steel tubular stub columns under long-term coupling effects of loading and chloride corrosion

研发了用于钢管混凝土轴压短柱在长期荷载-氯盐腐蚀耦合作用下的试验装置和方法。分别进行了7个圆钢管混凝土轴压短柱和4个圆钢管轴压短柱在浓度为3.5%的Na Cl溶液中腐蚀下的长期荷载试验研究。试验结果表明,长期荷载会使试件刚度降低很多,但对其承载力影响相对较小。腐蚀对试件的承载力和刚度的削弱都很大,且对圆钢管试件的削弱程度高于对圆钢管混凝土试件的;持载-腐蚀耦合作用对试件的承载力和刚度的降低都很大,并且对于圆钢管试件,随着持载等级和浸入程度的增大而更加明显。总体而言,对于钢管混凝土试件,持载-腐蚀耦合作用对其承载力和刚度的降低要大于单纯持载作用和单纯腐蚀作用对其承载力和刚度的降低的简单叠加。

Experimental instrument and testing methods were developed to study the long-term coupling effects of loading and chloride corrosion on the concrete-filled steel tubular(CFST) stub columns. Overall 7 circular CFST and 4 circular steel tubular stub columns were tested under the long-term loading in the Na Cl concentration of 3.5%. The experimental results show that the stiffness of specimens can be reduced greatly under the long-term loading. However, its effect on the load carrying capacity is relatively minor. Corrosion can remarkably reduce both the load carrying capacity and the stiffness of specimens, but the reduction influences on the steel specimens are more significant compared to the CFST specimens. The long-term coupling action of loading and corrosion may obviously decrease both the load carrying capacity and the stiffness, and its effect may become more significant with the increase of long-term loading level and corrosion degree for steel specimens. In general, for concrete-filled steel tubular specimen, the long-term coupling effect of loading and corrosion on the deterioration of load carrying capacity and stiffness is more significant than the simple superposition of load carrying capacity or stiffness reduction due to single long-term loading effect and single corrosion effect.