纤维布加固无粘结预应力梁抗弯试验研究

通过试验对纤维布加固无粘结预应力梁的破坏形态、受力性能、截面应变分布以及挠度变化等进行了研究，主要讨论了加固梁在不同纤维布加固层数、不同加固前预损伤作用和不同加固纤维材料下的性能．试验结果表明：通过粘贴芳纶纤维布、碳纤维布材料都可以有效地提高无粘结预应力梁的受弯极限承载力；当采用多层纤维布加固时，加固梁的受弯极限承载力提高幅度与粘贴纤维布层数的增加呈单调递减的规律；加固前，施加20％、40％对比梁极限承载力预损伤对加固性能影响不大；同层数纤维布加固，芳纶纤维布与碳纤维布加固梁的受力效果相似，受弯极限承载力相近，裂缝开展和刚度变化存在差异．在试验研究的基础上，通过有限元软件ABAQUS进行了模拟计算研究，模拟结果表明，ABAQUS可以真实反映纤维布加固无粘结预应力梁的整个受力过程，模拟值与试验值吻合较好．最后根据试验以及数学模拟中反映出的规律，建立了纤维布加固无粘结预应力梁极限抗弯承载力的实用理论公式，理论计算结果与试验结果符合较好．

Experimental Research on Bending Capacity of Concrete Beams Prestressed with Unbounded Tendons Strengthened with Fiber Reinforced Polymer

Experimental research on damage morphology, mechanical properties, cross section strain distribution and deflection variation of the concrete beams prestressed with unbounded tendons that were strengthened with fiber rein forced polymer （FRP） was carried out, and the behaviors of reinforced concrete beams with different FRP numbers of layer, different pre-injuries before reinforcement and different fiber reinforced materials were mainly discussed. The experimental results show that both AFRP and CFRP can effectively improve ultimate fiexural capacity of con crete beams prestressed with unbounded tendons; when using multilayer FRP, reinforced beam ultimate flexural capacity monotonically decreases with the increase of FRP layer number; before the reinforcement, when applying 20% and 40% contrast beams of pre-injury, the ultimate flexural capacity on the performance of reinforcement is not obvious; with the same number of FRP layers, the ultimate flexural capacity and stress effect of strengthened beams with aramid fiber reinforced polymer （AFRP） and carbon fiber reinforced polymer （CFRP） are similar, hut the ~rnekdevelopment and change of stiffness are different. Based on the experiment, the results of concrete beams prestressed with unbounded tendons strengthened with FRP were accurately simulated through the finite element software ABAQUS, and the simulated and experimental results are similar. Finally, according to the analysis of test and nu- merical results, the theoretical and practical formula for calculating the ultimate flexural capacity of concrete beams prestressed with unbounded tendons strengthened with FRP was established. The results show that the theoretical cal- culation is in accordance with the experimental data.