近年采用外部粘结纤维增强复合材料(FRP)来加固结构越来越受到许多研究开发机构和生产单位的重视。结合作者在FRP方面的研究成果和最新开发出的高强高性能的PBO纤维材料，系统地提出了一种更为有效的预应力外粘结加固方法；通过与玻璃纤维、炭素纤维和芳纶纤维等的比较，认清了新型PBO纤维材料的特性；根据既有的试验和研究成果提出了一套完整的预应力加固方法的流程，包括概念、原理和几种降低端部界面应力和新型锚固的措施；室内小型试验和室外大型试验的结果表明，PBO片材预应力技术能够提供令人满意的加固性能。

The application of externally bonded fiber reinforced polymer (FRP) laminates to the exposed faces of concrete members provides an innovative and efficient rehabilitation method for strengthening and upgrading structurally inadequate or functionally obsolete concrete structures. However, FRP laminates unlike the cold worked steel exhibit elastic-rupture behavior and also the limited bond capacity of FRP-concrete interface often fails the retrofitted system in an undesirable brittle manner, which leaves FRP material unused with more reserves. Moreover, enhancements in cracking and yield load due to FRP bonding are not significant. To take full advantage of FRP laminates, more gains can be achieved by prestressing the fibers prior to bonding them. Traditional practice is to pretension fiber sheets impregnated with adhesive or FRP plate, which is time-consuming, difficult to apply in the field and ensure a perfect bond at the interface. A newly-developed PBO fiber possesses high modulus, high strength and higher energy absorption capability as compared to carbon and aramid fibers, and PBO fiber sheet can be pretensioned to over 70% of its tensile strength without being impregnated with adhesive. All these make such material suitable to be prestressed for strengthening concrete structures. Based on the experiments and theoretical studies, a comprehensive strengthening method with prestressed PBO sheet is established including concept, working principle and corresponding countermeasures, whose strengthening effect is validated by both laboratory and field experiments.