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通过对23个钢筋混凝土试件的静载和重复荷载作用下拔出试验,研究了重复荷载作用下钢筋峰值应变和残余应变、自由端和加载端滑移发展特征,得到了重复荷载作用下黏结应力-滑移滞回曲线变化规律。运用试验测定的钢筋应变,计算了静载和重复荷载作用下锚固端黏结应力分布曲线,总结了重复荷载作用下峰值黏结应力、残余黏结应力变化特征,分析了锚固端黏结应力分布机理。研究结果表明:重复荷载作用后黏结强度并不受重复次数影响;重复荷载作用下,自由端、加载端峰值滑移量和残余滑移量发展均符合疲劳破坏的三阶段特征;当滑移量累积到静载作用下破坏时的峰值滑移量时,发生黏结疲劳破坏;随着重复次数的增加,黏结应力沿锚固长度的分布出现明显的双峰现象,最大黏结应力位于距离加载端和自由端约1/4锚固长度位置处。研究结果可为深入研究混凝土结构疲劳性能提供依据。
By static load on the reinforced concrete specimens 23 and a pull out test was repeated load, and peak strain were studied steel residual strain under repeated loading, the free end of the loading end of the slip and development characteristics obtained under the bonding REPEATED LOADING Variation of stress - slip hysteresis curve. Using steel test measures the strain, the bond stress distribution curve calculated static load and repeated load under the anchor end, summarize the peak stress REPEATED LOADING bond, the bond residual stress characteristics, the distribution mechanism bond stress anchorage ends. The results show that: the bonding strength after repeated loading is not affected by the number of repetitions; under repeated loading, the free end of the loading end of the peak and residual slip slip amount three stages are in line with the development of fatigue fracture characteristics; slip amount when the cumulative amount of the peak slip failure under static loads, fatigue damage occurs bond; with the increase of the number of repetitions, distributed along the length of the anchorage bond stress apparent double peaks, the maximum bond stress loading end and free at a distance End about 1/4 anchorage length position. The results provide the basis for further study on the fatigue behavior of concrete structures.