疲劳荷载作用下植筋锚固粘结的滑移性能

为研究疲劳荷载对植筋拉拔承载力、粘结应力的影响，设计植筋直径为16~25 mm、锚固深度为10d~25d（d为植筋直径）的10组拉拔试件进行疲劳试验，试件经200万次荷载上限为0.45P_u的疲劳加载后均未破坏，施加静载至破坏。加载过程中测量植筋的应变、滑移和荷载。结果表明：疲劳荷载削弱了承载能力，试件经疲劳荷载作用后极限承载力下降，粘结应力的减小随循环加载次数增加呈对数发展趋势。分析了粘结应力与试件破坏形态的关系。对于拔出破坏的试件，达到一定植筋深度后，胶筋界面的粘结应力是控制试件破坏与否的主要因素。增加植筋直径和锚固深度，粘结应力峰值逐渐降低，沿锚固长度的应力分布曲线趋于平缓，提高了植筋整体受力性能。

Bond slip behavior of post-installed anchorage under fatigue load

Through the fatigue test of 10 groups of drawing specimens with diameter of planting reinforcing bar of 16~25mm and embedment depth of 10d~25d (d is diameter of planting reinforcing bar ), effect of fatigue load on tensile strength and bond stress of anchor bars had been studied.The specimens were not damaged after 2 million times of fatigue loading with an upper limit of 0.45P_u, then applied static load to failure.Strain, slip and load of planted bars are measured during loading.Results demonstrate that the fatigue load weakens tensile strength, and the ultimate load decreases after fatigue loading.The decrease of bond stress has a logarithmic trend with the increase of cyclic loading times.The relationship of the bond stress and the failure form of the specimen is analyzed.It is found that the bond stress at the interface between rebar and chemical adhesive is the main factor to control whether the specimen failure or not when reaching certain embedment depth.Increasing the diameter and embedment depth of anchor bar, the peak of bond stress gradually decreases; the stress distribution curve along the embedment length tends to be gentle, which improves the overall stress performance of the anchor bar.