FRP复合材料及其在工程结构加固修复中的应用

FRP(纤维增强复合材料)在工程结构中的应用是近年来研究的热点.FRP因其良好的性能,不仅可以作为结构加固补强材料,而且在新建工程结构中,FRP作为新型建筑材料也越来越受到工程界的重视,国内外有关研究和工程单位开展了大量的研究和实践应用.综合国内外最新研究成果,详细介绍了结构工程中常用的FRP 材料及其优势,FRP加固混凝土结构,FRP加固砌体结构以及FRP加固钢结构在国内外的应用和发展概况,最后提出了前景展望,以其促进FRP加固技术在我国土木工程中的研究和应用.     

FRP加固砌体墙体结构技术理论研究与应用

FRP加固技术目前是国际土木工程领域研究开发的一个热点,其不仅可以适用于加固砌体构件的局部开裂;并且可以用于承载力不足的砌体加固。综合现阶段国内外纤维增强复合材料FRP加固砌体结构的研究,系统地介绍了FRP材料近年来加固、修复、改善砌体结构的技术和应用,较全面介绍了FRP的性能、FRP加固技术的优势和施工工艺。研究成果表明,FRP加固砌体结构可以有效地改善砌体的破坏机理和受力性能,改善砌体结构的抗震受剪承载力和变形性能,有效地将砌体的脆性破坏形态转化为其他破坏形态。     

FRP片材在砌体结构加固中的应用

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。本文围绕国内外FRP加固技术的研究现状以及最新进展,从FRP加固砌体结构技术的研究方面进行综述。试验研究表明: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。     

喷射FRP在砌体结构加固中的研究与应用

对目前国内外应用喷射FRP技术加固砌体结构的研究状况进行介绍和分析。首先介绍了喷射FRP加固技术的特点和应用于砌体结构的优势,然后介绍了喷射FRP加固砌体结构技术的研究与应用现状,从抗震、抗剪及抗压性能等几个方面展开分析;最后对喷射FRP的研究现状进行总结并对该技术未来的发展进行了展望。     

FRP片材加固混凝土梁剥离承载力计算及设计

粘贴FRP片材加固混凝土结构的界面剥离是该加固技术的关键问题。根据近年来对FRP片材加固混凝土的界面粘结性能、FRP片材加固混凝土梁的受弯和受剪剥离性能的试验和理论研究,介绍了FRP片材加固混凝土梁的抗弯和抗剪剥离承载力的计算和设计方法,及其有关保证剥离承载力的构造要求。     

FRP片材加固钢筋混凝土梁的研究进展

80年代以来,FRP(纤维增强复合材料)作为一种高性能的新型混凝土结构加固补强材料受到科研院所和工程界的广泛关注[1]。迄今为止,国内外关于FRP片材加固钢筋混凝土结构研究的试验和理论研究已相当丰富,并在工程界得到大量实践应用。本文着重介绍了FRP片材加固钢筋混凝土梁的抗弯性能、抗剪性能、以及裂缝、刚度研究,以期为FRP片材的进一步研究和应用提供参考。     

预应力FRP技术的研究与发展

介绍了国内外预应力FRP技术的研究现状,主要涉及了FRP材料的物理性能及预应力FRP筋作为结构受力筋和预应力FRP片材加固技术的国内外研究成果,最后对预应力FRP技术在国内的研究与应用提出了建议.     

FRP加固混凝土研究现状与展望

纤维增强复合材料(FRP)是一种高性能新型结构材料,近年来在混凝土结构加固修复领域中得到了广泛的应用。综述了国内外学者对FRP加固混凝土的研究现状,介绍了FRP材料的分类以及FRP片材的优点,总结了基于断裂力学的6种FRP与混凝土界面黏结滑移模型,在此基础上,归纳总结了FRP加固混凝土中存在的不足,并对未来FRP加固混凝土研究方向进行了展望。     

FRP片材加固混凝土板研究进展

为研究FRP片材对加固混凝土板性能的影响,本文结合国内外学者对FRP加固混凝土板的受弯性能、承载力、疲劳性能及耐火性能等方面的研究进行了探讨。从已有的研究成果中可以发现,FRP加固混凝土结构的研究主要是对短期性能和承载力方面的研究,而对FRP加固混凝土结构长期性能和耐久性能方面研究较少,对于FRP片材加固混凝土板的试验研究和理论分析方面的剥离破坏开展则更少。因此,对FRP片材加固凝土板的研究具有一定的实际意义和工程前景。     

预应力FRP片材加固混凝土构件施工技术研究

预应力纤维增强复合材料（FRP）片材加固混凝土构件的技术是土木工程领域前沿的研究课题。本文探讨预应力FRP加固混凝土构件的力学性能,介绍该类加固技术预应力的施加方法,并对预应力放张后的关键问题进行分析,为实际工程应用提供参考。     

In-plane retrofitting of masonry panels with fibre reinforced composite materials

Research activities carried out during the past years concerning the use of fibre reinforced polymers (FRP) as external reinforcement of masonry walls have shown that this system considerably improves structural stability and ductility with minimum increase in the load transmitted to foundations. However, different aspects of this retrofitting system should still be analyzed.The mechanical behaviour under in-plane compression and diagonal compression of clay masonry panels reinforced or repaired with carbon fibre reinforced polymer laminates is experimentally assessed in this paper. The results show that if correct retrofitting schemes are chosen, reinforcement and repairing with fibre reinforced polymers improves masonry behaviour, increasing ductility and, in some cases, ultimate strength and even stiffness. In this way, brittle behaviour and sudden failure of unreinforced masonry can be avoided.     

Shear behavior of masonry panels strengthened by FRP laminates

The present experimental study, performed on brick masonry panels strengthened by Fiber Reinforced Polymer (FRP) laminates, was aimed to investigate the efficiency of an alternative shear reinforcement technique. A series of nine unreinforced masonry (URM) panels and 24 strengthened panels have been subjected to diagonal compression tests. Different reinforcement configurations were evaluated. Experimental results pointed out that FRP reinforcement applied only at one side of the panels did not significantly modify the shear collapse mechanisms (diagonal splitting) of the URM; while double-side configurations provided a less brittle failure and a noticeable ultimate capacity increase. Performances of the different reinforcement configurations are compared in terms of strength and mechanism of failure; finally, experimental results are also used to calibrate existing analytical formulations for ultimate shear strength prediction.     

建筑结构检测与加固方法

建筑结构检测和加固是发现建筑结构问题、提高建筑质量的重要保障。文章简单介绍了砌体结构、混凝土结构以及钢结构三种建筑结构的检测和加固方法。     

碳纤维片材加固钢筋混凝土梁的可靠度分析

建立了 FRP 加固钢筋混凝土梁的极限状态方程;讨论了碳纤维片材的耐久性、纤维布与混凝土间界面的粘结耐久性对加固有构件抗力的影响;通过一次二阶矩法计算了《碳纤维片材加固混凝土结构技术规程》(CECS146:2003)加固的钢筋混凝土梁抗弯可靠度指标,计算结果大于3.7,表明满足《建筑结构可靠度设计统一标准》(GB50068-2001)对抗弯可靠度指标的要求。     

砌体房屋墙体加固方法研究与应用

文章介绍了砌体房屋墙体的加固方法,并着重介绍了被现行抗震加固规程明确认可的可视为改变了原有砌体结构体系的加固方法—钢筋混凝土板墙加固(简称"夹板墙")。但是夹板墙加固方法也存在着传统加固方法的缺陷,因此,探索出一种可以改变砌体结构体系的,安全、先进、合理的新加固方法是很有必要的。由此,提出了格构式钢板组合剪力墙加固砌体房屋的方法。     

多层砖混结构住宅应重视构造柱的工程质量

砖混结构住宅中钢筋混凝土构造柱的设置是非常重要的,通过实地观察发现了钢筋混凝土构造柱质量问题的一些通病,在设计中构造柱的设置不合理,不符合规范要求,更为严重的是钢筋的绑扎搭接,混凝土的浇捣、马牙槎的留置等问题不按规定施工,根据这些问题提出了具体的治理措施。     

Evaluation of debonding failure of reinforced concrete girders strengthened in flexure with FRP laminates using finite element modeling

The use of Fiber-Reinforced Polymer (FRP) materials dates back to the early 1940s when they were used in aerospace and naval applications. During the 1970s and early 1980s, FRP started being used in civil engineering applications for new construction, but more importantly for repair and strengthening of existing structures. However, experimental research showed that the typical failure mode of reinforced concrete (RC) structures strengthened with FRP composite materials is due to the debonding that occurs at the interface between concrete and FRP. The bond between FRP and concrete is therefore the key factor controlling the behavior of these structures since it limits the full use of the FRP strength. The paper evaluates the effect of the debonding failure on the response of FRP-strengthened RC beams. A nonlinear RC beam element with bond-slip between the concrete and the FRP laminates is developed and used to analyze several test specimens and to investigate their corresponding failure mode. The model was also used to study the reduction factor of FRP tensile strength of simply supported strengthened RC girders due to debonding failure. This reduction factor proved to be affected by several parameters: (a) the bond strength between FRP and concrete interface; (b) the concrete strength; (c) the thickness of FRP; (d) the modulus of FRP; (e) the width of FRP laminate; and (f) the development length of the FRP sheet. A large number of beam specimens were analyzed in order to conduct a thorough evaluation of debonding failure of RC beams strengthened with FRP laminates. Based on these studies, new equations that account for the aforementioned parameters were proposed to address the reduction in FRP strength due to debonding failure.     

Behaviour of a masonry arch bridge repaired using fibre-reinforced polymer composites

This paper describes a series of laboratory tests investigating the behaviour of a large model masonry arch bridge repaired with externally bonded fibre-reinforced polymer (FRP) on its intrados. Many similar masonry arch bridges form critical links in the world’s transport infrastructure, but they are often not suited to the increased demands of modern traffic loading, especially in ageing arch structures that have suffered structural deterioration. FRP plates, adhesively bonded to the intrados of the masonry arch are a convenient method for strengthening arch bridges. The tests described in this paper demonstrated that FRP strengthening is an effective technique for improving the structural performance of a masonry arch bridge.A two-span, single-ring semi-circular brick arch bridge was tested in this study, complete with fill material. Each of the spans was initially loaded to investigate their response and to establish a four-hinge collapse mechanism, simulating damage prior to strengthening. FRP strengthening was then applied to the two arches, and each of the spans was again tested separately until the failure of the strengthening system. The global (load and deflection) and local (crack width and FRP strain) response of the structure was recorded. The FRP strengthening resisted flexural crack opening in the masonry, and hence prevented a four-hinge mechanism collapse. Failure instead occurred when the FRP strengthening debonded from the masonry adjacent to an existing intrados hinge crack. As well as shear debonding adjacent to flexural cracks in the masonry, peel debonding occurred where shear deformation occurred across a masonry crack. Catastrophic collapse did not occur, as the FRP continued to contribute to the load capacity by acting as a tie after the ultimate load had been reached.     

在弯矩、剪力和反复扭矩复合作用下的碳纤维布加固RC箱梁抗扭性能试验研究

为研究碳纤维布加固弯矩、剪力和反复扭矩复合作用下的钢筋混凝土箱梁的抗扭性能,共设计制作了4根钢筋混凝土箱梁试件,其中3根采取碳纤维布加固、1根不加固作为对比试件。试验在自行研制的扭转试验装置上进行,对箱梁试件同步施加弯矩、剪力和反复扭矩作用。以加固方式和加固数量为主要研究参数,分析了箱梁试件的破坏机理、承载能力、变形能力和滞回性能等。通过各箱梁试件的碳纤维布和钢筋的应变变化规律,探讨了碳纤维布加固箱梁的抗扭工作机理;通过测得的各试件的扭矩-扭转角滞回曲线和骨架曲线,提出了碳纤维布加固钢筋混凝土箱梁的抗扭恢复力模型。从而为碳纤维布加固钢筋混凝土箱梁抗扭性能的理论研究和工程应用提供了重要的依据。     

建筑物加固技术探讨

首先简单介绍了当今社会的建筑物加固技术，总结了混凝土结构、砌体结构、钢结构三种建筑结构形式的加固技术，做了具体的分析论述，并举实例进行了论证，以起到抛砖引玉的作用。