框架梁增荷改造的加固

随着经济、科技和生活水平的提高 ,建筑物改变用途 ,结构所承担的荷载增加 ,致使原框架梁承载力不满足要求 ,需对框架梁进行加固处理。本文结合工程实例对在荷载增加时框架梁的加固处理进行了探讨     

西气东输黄河跨越工程裂缝原因分析及处理

西气东输黄河跨越工程采用悬索管桥跨越形式,塔基础采用整体扩大式混凝土基础,主索锚固和风索锚固墩,采用重力式混凝土锚固墩。冬季暖棚施工,拆模后混凝土表面出现大量裂缝,通过对设计、材料配比、施工、养护等进行分析测试后,提出了混凝土产生裂缝的原因,并采取了修补处理措施,现已使用5年,效果良好。     

震后碳纤维布加固钢筋混凝土构件的设计步骤

碳纤维布对于限制设备破坏以及不合格的钢筋混凝土构件的破坏具有很大优势,已经被广泛地用于建筑物抗震的局部修复。通过系统评估各种被加固构件的抗力机理和握裹力作用,探讨了抗震修复／增强技术有关的设计问题和细节准则,包括：屈曲、剪力、互搭接头承载力、塑性铰性能以及与植入钢筋有关的变形能力和包裹应变能力。     

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.     

Strengthening fire-damaged concrete by confinement with fibre-reinforced polymer wraps

Extensive research has shown that fibre-reinforced polymer (FRP) wraps are very effective for strengthening concrete columns for increased axial and flexural load and deformation capacity, and this technique is now widely used around the world. The study reported in this paper extends the FRP confinement technique to strengthening fire-damaged circular concrete columns. An experimental programme was undertaken to study the compressive strength and stress-strain behaviour of both unconfined and FRP-confined plain concrete cylinders after being heated to various elevated temperatures for up to four hours and cooled to room temperature. The results show that FRP confinement is highly effective for enhancing the load-carrying capacity of even severely fire-damaged concrete columns. The results also yield insights into the mechanics of FRP confinement of concretes of similar composition but with varying compressive strengths. A modified version of a pre-existing confinement model is proposed for use in designing FRP strengthening schemes for fire-damaged concrete columns.     

Behaviour of fire-exposed concrete-filled steel tubular beam columns repaired with CFRP wraps

This paper presents the test results of fire-exposed concrete-filled steel tubular (CFST) beam columns repaired by unidirectional carbon fibre reinforced polymer (CFRP) composites. Both circular and square specimens were tested to investigate the repair effects of CFRP composites on them. The test results showed that the load-bearing capacity of the fire-exposed CFST beam columns was enhanced by the CFRP jackets to some extent, while the influence of CFRP repair on stiffness was not apparent. The strength enhancement from CFRP confinement decreased with the increasing of eccentricity or slenderness ratio. Ductility enhancement was also observed except those axially loaded shorter specimens with rupture of CFRP jackets at the mid-height, occurred near the peak loads. However, the strengths of all repaired specimens have not been fully restored due to the long exposure time of them in fire. From the test results, it is recommended that, in repairing severely fire-damaged CFST members, slender members or those members subjected to comparatively large bending moments, other appropriate repair measures should be taken.     

新建砖混房屋砌体裂缝的初步研究

本文包括:(1)常见的典型裂缝;(2)砖砌体开裂的现象、特征原理;(3)防治方法的研究。     

加筋陡坡路堤施工技术

本文介绍了安同高速公路采用加筋陡坡路堤的原因及加筋陡坡路堤的施工工艺,并指出了施工中的控制要点和注意事项。     

采用CFRP覆层修复的钢管混凝土梁柱的抗火性能

介绍了通过单向碳纤维聚合物加固的钢管混凝土梁柱在高温下的试验结果。为研究CFRP材料的加固作用,对所有圆形和方形的构件进行了测试。试验结果表明,通过CFRP加固后CFST梁柱的承载能力有所提高,但CFRP对其强度的影响却不明显。当偏心率或长细比增加时,CFRP所带来的强度的增幅会减少。当结构处于最大载荷时,除了那些在中间部位没有CFRP覆层的轴向受力短柱外,构件延性也有所增强。但是由于长期暴露在火中,所有修复过的构件都不能完全恢复到以前的性能。试验结果表明,当修复火灾中严重受损的CFST构件为长细构件或者遭受相对较大弯矩的构件时,建议适当考虑其他修复方法。     

FRP加固砌体结构平面内剪切性能研究综述

对国内外关于FRP加固砌体结构平面内性能研究进行了介绍,包括单调荷载作用和循环荷载作用两方面内容,着重阐述了国内外学者对于FRP加固砌体结构抗剪承载力的计算方法,以促进相关试验研究及有限元分析。     

复合材料钢桥面铺装结构的试验研究

钢桥面铺装是桥梁建设的技术难题之一,铺装结构最常见破坏形式为层间的剪切破坏。本文介绍了FRP-沥青混凝土钢桥面铺装结构,其结构形式简单,结构功能全面,具有优于现有钢桥面铺装结构的技术和经济性能。对FRP-沥青混凝土钢桥面铺装结构进行了理论分析和模拟试验,结果表明:FRP层对钢板裸板的挠度和应变减小贡献最大,并且贡献比例随超载增大而增大。FRP-沥青混凝土钢桥面铺装结构可为钢桥面铺装设计提供一定的参考,对钢桥面铺装结构的技术创新和工程应用具有一定的使用价值。     

FRP片材加固钢筋混凝土梁裂缝分析

应用传统的钢筋混凝土结构裂缝分析方法对FRP加固试件在正常使用状态下的裂缝进行分析，结果显示，其理论计算值与试验值吻合较好，以更广泛的推广FRP加固技术的应用。     

FRP加固混凝土梁的非线性有限元分析

利用ANSYS软件建立了三个FRP加固钢筋混凝土梁的有限元模型,并将计算得到的梁的荷载-挠度曲线、极限荷载以及梁的破坏形态与试验结果进行对比,验证了所建立模型的正确性。     

FRP与混凝土界面黏结-滑移本构关系的试验研究

FRP与混凝土的黏结性能是外贴纤维增强聚合物加固钢筋混凝土结构技术的关键问题。采用修正梁模型,对9个外贴FRP条带加固混凝土受弯构件的黏结性能进行了试验研究,考察混凝土强度和FRP黏结长度对黏结性能的影响,分析了FRP应变以及局部黏结剪应力发展规律以及沿黏结长度在各级荷载下的分布规律,计算得到了局部黏结剪应力-滑移关系曲线。通过对试验结果的统计回归分析,提出3种不同复杂程度的局部黏结剪应力-滑移本构关系模型,3种本构关系模型与试验结果都吻合较好,可供实际加固改造工程应用以及完善相应规范的编制参考。     

FRP加固木结构的研究和应用现状

为了提高木结构的性能和耐久性,纤维增强塑料(FRP)已越来越多地应用于木结构加固.通过介绍国内外FHP加固木结构的研究和应用现状,分析了FRP木结构的研究和应用中的相关问题,同时,对其今后的发展与应用前景进行了展望.     

英国混凝土技术现状及研究动态简介

本文就英国应用各种矿物掺合料配制混凝土技术的现状作了简单介绍，并结合笔者在英国将近一年的访问研究工作，对曼彻斯特理工大学和谢菲尔德大学在混凝土耐久性，纤维增强复合材料（FRP）及其在混凝土中应用的设计规范，超细粉煤灰的性能及其在混凝土中的应用等研究领域作了动态简介。     

FRP加固混凝土结构耐久性能研究

目前，FRP加固混凝土结构在土木工程中应用越来越普遍，随着在工程上的广泛应用，FRP加固混凝土结构的耐久性问题成为了一个十分重要而迫切的研究课题。本文综述了近年来国内外在FRP加固混凝土结构耐久性方面的研究成果，介绍FRP加固混凝土结构后整体性能耐久性的研究方法和试验手段，并对今后的研究工作和实际工程提出了意见和建议。     

新型大断裂应变FRP约束混凝土圆柱的轴压性能

对新型大断裂应变FRP约束混凝土圆柱的轴压性能进行变参数的应力-应变全曲线研究,研究参数有FRP种类、包裹层数、非约束混凝土强度等。新型大断裂应变FRP约束混凝土的轴压性能与CFRP约束混凝土、GFRP约束混凝土、AFRP约束混凝土的轴压性能相比较,比较发现新型大断裂应变FRP约束混凝土轴压性能优于一般FRP约束混凝土。     

铝合金及FRP-铝合金组合结构在结构工程中的应用

首先介绍了铝合金材料及其铝合金构件的形式,分析了铝合金作为一种建筑材料的特点,并介绍铝合金桥梁结构、大跨空间结构和其它结构形式.考虑到铝合金的弹性模量相对钢材来说较低,因此铝合金结构往往受变形控制,这在一定程度上影响到其应用的范围.为此,本文提出了FRP-铝合金组合结构,不仅可以显著提高铝合金构件的刚度,也可显著提高其承载力,且仍保持铝合金构件的延性特征.本文针对这种新型高强轻质耐久的组合结构在国内外的应用现状进行了介绍,并讨论了其今后的发展.