套筒灌浆料与高强钢筋黏结性能试验与仿真分析

Test and Simulation on Bond Behavior Between Sleeve Grout and High Strength Steel Rebar

摘要:

探究了钢筋套筒灌浆连接中套筒灌浆料与高强钢筋的黏结性能。以钢筋直径、钢筋黏结长度为试验变量，浇筑27个试件开展拔出试验。试件的失效模式包括钢筋断裂、钢筋黏结滑移失效、劈裂等三种类型，钢筋直径、钢筋黏结长度均对失效模式产生影响，其中，钢筋黏结长度的影响更加明显。此外，钢筋黏结滑移失效时，试件的荷载-滑移曲线初始下降段出现荷载骤降的现象，其下降幅值约为0.1～0.3倍峰值荷载。进一步提出了套筒灌浆料与高强钢筋的黏结-滑移本构模型，并基于试验数据拟合分析给出了黏结强度、峰值滑移、残余黏结强度等参数的计算表达式。最后，通过有限元模拟进行拓展分析，发现钢筋直径（d）12、16、18mm的拔出试验试件发生钢筋断裂时钢筋黏结长度分别不低于5d、7d、7d。这些发现可为钢筋套筒灌浆连接设计以及承载力计算方法提供依据。

Abstract:

Bond behaviors of sleeve grout and high strength steel rebar were investigated for the grouted sleeve connection. Taking the diameter of steel rebar and its embedded length into account， the pull-out test with 27 specimens was employed to investigate the bond behaviors between sleeve grout and steel rebar. Based on the test results， it is found that there are three failure patterns of specimens after loading， namely， steel rebar fracture， bond-slip failure and splitting failure， which were affected by the diameter of steel rebar and its embedded length especially. In addition， there is a sudden drop with a range of 0.1 to 0.3 times peak load in the initial decline part of load versus slip curves of specimens with bond-slip failure. Furthermore， bond-slip constitution models were initiated， and expressions of the bond strength， peak slip and residual bond strength were built by the data fitting for the specimens with bond-slip failure. Finally， the finite element analysis was used to stretch these previous expressions. Combined with the results of simulation and the test， it is found that the embedded length of steel rebars with a diameter （d） of 12mm， 16mm and 18mm should not be less than 5d， 7d and 7d respectively when the failure mode of rebar fracture occurs to the pull-out test. These findings are beneficial to the design of the grouted sleeve connection and form its bearing capacity calculation method in the further study.