动荷载下锈蚀钢筋混凝土粘结滑移特性的试验研究

通过对不同锚固长度、不同锈蚀程度的18个柱式试件动态拉伸试验,研究了锈蚀程度、锚固长度对钢筋与混凝土之间粘结滑移的影响。结果表明:自由端初滑移是在整个锚固长度内胶着力破坏后才开始;钢筋锈蚀深度越大,自由端初滑移荷载越小,加载端和自由端滑移差越小;锚固长度越短,两端滑移差越小。根据实测资料,拟合出了残余滑移量计算公式。基于几个循环的粘结应力与滑移曲线的分析,初步探究了动荷载下锈蚀钢筋混凝土的粘结机理,动荷载下肋前混凝土受压变形比静载作用下的大,钢筋锈蚀物膨胀产生内裂缝,从而使得动载下锈蚀钢筋与混凝土之间的滑移量比静载下钢筋与混凝土之间的滑移量大。研究结果对动力荷载下服役钢筋混凝土结构的受力性能分析和结构耐久性设计具有指导意义。

An experimental study on the bond-slip behavior of corroded steel bars in concrete under dynamic loads

Dynamic load tests are conducted on 18 large size column-type specimens with reinforcing bars in various states of corrosion and different anchorage lengths.The effects of corrosion and anchorage on bond-slip between the concrete and the steel bars are studied.The result indicates that the slip-initiation at the free end starts when the adhesion between the concrete and the corroded steel bars over the entire length of anchorage vanishes.The higher the degree of corrosion,the lower the slip-initiation load will be,and the less the difference in slips between the free end and the loaded end.The shorter the anchorage length,the less the difference between the free end slip and the loaded end slip will be.Based on the test results,a formula to calculate the residual slip is established.The dynamic bond-anchorage mechanism of concrete reinforced with corrosive bars is studied.The result indicates that the slip between corroded re-bar and concrete under dynamic load is larger than that caused by static load.