极限状态时CFRP筋粘结式锚具粘结应力分布

Bond Stress Distribution of Bond-type Anchors for CFRP Tendons under the Ultimate Tensile Capacity

结合不同荷载水平下CFRP(Carbon Fiber Reinforced Polymer/Plastics)筋的粘结应力分布特点,详细分析了荷载传递机制,论证了极限状态时粘结应力分布是光滑平顺的,并指出了BBA模型的不足之处,从而提出了光滑曲线模型,对CFRP筋沿锚固长度方向的粘结应力和轴力计算公式进行了推导,通过算例对光滑曲线模型的可靠性进行了验证。研究表明,极限承载力的计算结果与实测结果吻合较好,但由于理论模型中峰值应力为埋长小于13倍CFRP筋直径的平均粘结应力,它比实际峰值应力小,导致极限承载力的计算结果均比实测结果小;光滑曲线模型比BBA模型更靠近实测结果;锚固长度越大,极限状态下粘结应力分布越不均匀,极限拉力的实测结果与理论结果差值也越大。研究成果可以为粘结式锚具的设计提供参考。

Based on test data on the bond stress distribution of bond anchorages along the bonded length, the working mechanism of bond anchorages for Carbon Fiber Reinforced Polymer/Plastics （CFRP） tendons is analyzed.And smooth bond stress distribution along bonded length under the ultimate tensile capacity is demonstrated.The bond stress distribution model is presented by Burong, Brahim, and Adil （BBA model） when the ultimate tensile capacity of a bond anchorage occurs, but the curve of BBA model is not a smooth curve along the bonded length, so the proposed model is improved as smooth. Based on the smooth curve model, the tensile capacity and the bond stresses at the tendon-grout interface of bond anchorages for CFRP tendons is obtained.The research shows that the ultimate tensile capacity of the proposed model and the BBA model are less than the experimental results when the peak bond stress is calculated with the assumption of uniform bond stress distribution for bonded length less than 13 md diameters.The smooth curve model＇ s results are closer to the experimental results than the BBA model＇ s results. The uneven extent of the bond stress distribution along the bonded length under the ultimate tensile capacity increases with the bonded length increasing.The result can provide a reference for design of the bond -type anchorage for CFRP tendons.