FRP加固技术研究新进展

纤维增强复合材料(FRP)在加固工程中的应用是土木工程研究热点之一。围绕国内外FRP加固技术的研究现状以及最新进展,从混杂纤维材料(HFRP)加固、FRP加固砌体结构、预应力碳纤维布(CFRP)加固、CFRP与钢板复合加固混凝土结构等技术的研究方面进行综述。试验研究表明:混杂纤维加固柱的承载力和变形能力优于单一纤维加固,且在承载力提高幅度相同的情况下,成本显著低于CFRP加固柱;FRP加固砌体结构可以提高砌体结构的抗震、抗剪和平面外抗弯性能;预应力CFRP加固技术结合了预应力技术和FRP粘贴技术,能明显提高梁的刚度、屈服荷载和极限荷载,其提高程度随预应力CFRP的用量和预应力水平的提高而增大。预应力加固的研究主要集中于预应力控制值、端部锚固和预应力损失方面。CFRP与钢板复合加固混凝土结构技术作为一种新型的加固技术,可以直接利用钢材参与受力,钢材形成的骨架在约束混凝土变形的同时,还提高了CFRP的利用效率,从而大幅度提高构件的极限承载力,改善构件的工作性能。

New Progress in the Study of the Technology of Reinforcement with Fiber Reinforced Plastics

The application of Fiber Reinforced Plastics(FRP) in reinforcement engineering is one of the most popular fields in the studies of civil engineering.A concise state-of-the-art survey and new progress of the technology of FRP strengthening are presented,including studies in terms of hybrid fiber reinforced plastics(HFRP),masonry structures strengthening with FRP,prestressed carbon fiber reinforced plastics(CFRP) strengthening and combination strengthening with both CFRP and steel sheets.Experimental studies show that both the load carrying capacity and the plasticity of concrete columns strengthened by means of HFRP are significantly higher than those strengthened with single type of fiber,and that with the same bearing capacity increase,HFRP strengthening cost is greatly reduced comparing with that of CFRP strengthening.With the FRP strengthening system,performances of masonry structures increase obviously in terms of seismic resistance,shear resistance and flexural capacity out of plane.Combined with technique of prestressing and bonding FRP,prestressed CFRP strengthening system can significantly increase the rigidity,yield loads and ultimate capacity of concrete beams.The degree of increase depends on the ratio and prestressing level of CFRP.Studies on prestressing strengthening are focused on prestressing level,end anchorage and prestressing losing etc.As a new type of strengthening technique,combination strengthening with bonding CFRP and steel sheets can greatly improve the ultimate carrying capacity and the performance of concrete structures,because the steel sheets,which directly work together with concrete,can confine the deformation of concrete and meanwhile increase the efficiency of CFRP.