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为了研究碳纤维增强复合材料(carbon fiber reinforced polymer,CFRP)筋黏结型锚具的受力特征,设计了直筒式、内锥式和复合式3种锚具,并采用有限元法分析3种锚具内部筋材和套筒自身的应力分布特征,然后通过试验测试CFRP筋材在锚具内部的应力变化规律和滑移特征,并测试锚具套筒自身的三向应力,研究锚具形式、锚固长度等对锚固性能的影响以及锚固传力机理。研究结果表明:锚具端堵的设置能使受荷端筋材应力峰值处于锚具当中,复合式锚具的传力模式最合理,可以防止内锥式锚具出现切口效应;在加载前期,黏结应力峰值靠近受荷端,随着荷载的持续增加,受荷端逐渐只剩下残余黏结强度,在加载后期,黏结应力峰值靠近锚具自由端;CFRP筋材在自由段的应力-应变基本呈线性关系;锚具的荷载-滑移曲线呈明显的非线性趋势,在加载前期,CFRP筋材的滑移量较小,随着荷载的持续递增,筋材的滑移量迅速增大,当接近破坏时,滑移量明显增加;随着荷载的逐渐增加,筋-胶界面上的黏结应力先增加到峰值,然后其化学胶着力逐渐失效,只剩下残余应力;黏结应力峰值由受荷端逐渐向自由端转移,表现为自由端附近套筒的正应力最大,套筒上的应力分布可以间接反映出CFRP筋材的应力变化情况和滑移情况。
In order to study the stress characteristics of CFRP tendon bond anchors, three kinds of anchors, ie, straight tube, inner cone and composite, were designed and three kinds of anchors were analyzed by finite element method Internal stress and self-stress distribution characteristics of the sleeve, and then through the test of CFRP tendons internal stress variation and slip characteristics of the anchor, and test the three-dimensional stress of the sleeve itself to study the anchor form, anchorage Length and other effects on the anchoring performance and anchoring force transmission mechanism. The results show that: the setting of the end plug of the anchor can make the stress peak of the load end tendon be among the anchors, and the force transmission mode of the composite anchor is the most reasonable, which can prevent the incision effect of the inner cone anchor. In the early stage of loading, The peak value of the bond stress is close to the load end. As the load continues to increase, the remaining bond strength gradually remains. At the late loading time, the peak value of the bond stress is close to the free end of the anchor. The stress- The load-slip curve of anchorage shows a significant nonlinear trend. At the early loading stage, the slippage of CFRP tendons is small, and as the load continues to increase, the slip of tendons increases rapidly, When approaching the failure, the slip increased obviously. As the load increased, the bond stress on the tendon-rubber interface first increased to the peak value, and then gradually lost its chemical adhesion, leaving only the residual stress. The peak value of the bond stress The load end gradually migrates to the free end, which shows that the normal stress of the sleeve near the free end is the maximum. The stress distribution on the sleeve can indirectly reflect the stress change and the slip of the CFRP tendon.