植筋法在加层改建工程中的应用

本文以某综合楼的扩建加层为例，介绍化学胶植筋法在工程改造中的具体应用，并就柱、梁、板三个不同的结构组成部分来讲述植筋施工的特点和难点，供钢筋混凝土框架房屋的结构改造及加固所参考。     

南航凯宾斯基饭店结构改造及加固

针对业主要求在建的凯宾斯基饭店高层建筑由四星级宾馆改造为五星级宾馆,设计对原有结构进行了加层、增加游泳池、加固地梁等改造工作。对改造后的建筑采用原设计规范进行了结构整体分析,结果满足规范要求。工程采用了植筋、粘钢等多种方法完成了对原结构的加固和改扩建。所采用的加固改造方法可供类似的改扩建工程参考。     

浅析植筋技术在旧混凝土堤岸加固中的应用

结合实际工程,介绍了植筋技术在旧混凝土堤岸加固工程中的施工工艺,并阐述了植筋技术应用时的安全措施及注意事项,通过植筋技术的应用减轻了对原有结构构件的损伤,从而减少了加固改造工程的工程量。     

某混凝土框架结构抗震加固改造综合设计

结合某典型混凝土框架结构抗震加固改造设计实例,在对原结构分析验算的基础上,采用增大柱截面法和植筋加固补强法对框架柱、基础进行加固改造、抗震设计和施工,并对加层设计后新旧结构之间的连接节点作了设计探讨.经过位移复核以及建筑使用情况观察,证明了该综合加固改造设计方案达到了预期的效果,可为同类工程提供有益参考.     

植筋技术浅论

植筋技术作为对混凝土结构进行加固改造的技术，在目前工程维修改造得到了广泛的应用，本人有幸在湖南省人大常委会办公楼改造工程中参与工程植筋施工的监理，对植筋技术有了初步的探究，植筋技术规范出台后，我对植筋技术的实践和理论的认识有了进一步提高，特以本文将对该技术的认识总结归纳。[第一段]     

碳纤维布增强植筋加层框架抗震性能试验研究

基于一榀钢结构植筋加层框架和一榀碳纤维布节点加固的植筋加层框架的1/3缩尺模型进行低周反复荷载试验,对采用无机锚固材料植筋加层后框架的破坏形态、滞回曲线、刚度退化、位移延性和耗能能力等抗震特性进行研究。试验结果表明:高强早强水泥基无机锚固材料在植筋结构上可以很好地满足工程对其力学性能的要求;使用无机锚固材料植筋技术,对既有混凝土框架结构进行钢结构加层后,结构整体抗震性能较好;使用碳纤维布材料对植筋节点进行加固后,加层框架的破坏机制由混合铰破坏转为梁铰破坏,结构的延性、耗能能力等抗震性能的提高较为明显。     

植筋技术在混凝土结构加固改造工程中的应用

植筋技术已在混凝土结构加固改造工程中得到广泛应用。本文结合以往工程经验，介绍了植筋技术的应用形式，设计建议，防火要求以及粘钢技术的综合应用。     

攀枝花某学校食堂综合加固改造设计

结合攀枝花某学校框架结构食堂的加固改造设计实例,在对原结构分析验算的基础上,介绍采用增大柱截面法和植筋加固补强法对框架柱、基础进行加固设计、施工,并对加层设计后新旧结构之间的连接节点作了设计探讨。经过位移复核以及建筑使用情况观察,证明了该综合加固改造设计方案达到了预期的效果,为同类工程提供了有益参考。     

植筋新法在火力发电厂改造工程土建结构中应用

1.前言 在火力发电厂土建结构中,常有埋件遗漏,改造加固工程中结构加固、增加埋件,本文介绍植筋新法--种新型施工工艺处理方案在洛河电厂#1机组(300MW)技改和马鞍山第二发电厂改造等火电工程中应用,并取得良好效果.     

高等级宾馆建筑混凝土结构加固技术的研究与应用

通过北京京西宾馆西楼改造工程实践,探索了在高等级宾馆建筑混凝土结构加固中,应用树根桩加固基础、喷射混凝土加强柱梁以及利用消能阻尼器和化学植筋法强化结构的可行性。     

Strain monitoring of RC members strengthened with smart NSM FRP bars

Fiber-reinforced polymer (FRP) bars can be used as internal reinforcement for new reinforced concrete (RC) structures and as near-surface mounted (NSM) reinforcement for the strengthening of RC structures. The NSM method is an emerging strengthening technique for RC structures, where FRP bars are embedded into grooves cut in the cover of RC members. In both cases, strain monitoring of the FRP bars is desirable either for the investigation of the structural behavior or for the long-term health monitoring of the structure. This paper presents a study in which fiber-optic sensors were embedded into glass FRP (GFRP) bars to produce smart GFRP bars for NSM applications. The manufacturing process of the smart FRP bars is illustrated and their performance in tensile, bond and beam flexural tests is examined to assess the effectiveness of these smart FRP bars for achieving the dual purpose of structural strengthening and strain monitoring. On the basis of the test results, the advantages and limitations of fiber-optic sensors compared to electrical strain gages in the strain monitoring of NSM FRP bars are discussed. The bond and beam test results also confirm the effectiveness of the NSM method for the strengthening of RC structures.     

Influence of chloride corrosion on the effective mechanical properties of steel reinforcement

This paper presents a methodology to develop advanced reduction factors for the effective mechanical properties of corroded steel reinforcement of reinforced concrete (RC) members. The reduction factors (mainly developed for bare steel reinforcement) reported in the literature scatter over a large range. In this regard, critical questions arise, such as the reliability and accuracy of the reduction factors of bare steel bars to evaluate residual capacity of corroded RC structure. This paper will provide answers to these questions based on reviewing past studies and the results observed from experimental inspection of corroded steel reinforcement carried out in this research. The results show using the reduction factors of bare steel bars to estimate residual capacity of corroded RC structures is not safe because they are significantly lower than the reduction that happens in real corroded RC columns.     

Behavior and capacity of RC beams strengthened in shear with NSM FRP reinforcement

A recent and promising method for shear strengthening of reinforced concrete (RC) members is the use of near-surface mounted (NSM) fiber-reinforced polymer (FRP) reinforcement. In the NSM method, the reinforcement is embedded in grooves cut onto the surface of the member to be strengthened and filled with an appropriate binding agent such as epoxy paste or cement grout. Only a few studies have been conducted to date on the use of NSM FRP reinforcement for shear strengthening of RC beams. These studies identified some critical failure modes related to debonding between the NSM reinforcement and the concrete substrate. However, more tests need to be conducted to identify all possible failure modes of strengthened beams. Moreover, virtually no test results are available on the behavior of shear-strengthened beams containing steel shear reinforcement, and on the effect of variables such as the type of epoxy used as groove filler. This paper illustrates a research program on shear strengthening of RC beams with NSM reinforcement, aimed at gaining more test results to fill the gaps in knowledge mentioned above. A number of beams were tested to analyze the influence on the structural behavior and failure mode of selected test parameters, i.e. type of NSM reinforcement (round bars and strips), spacing and inclination of the NSM reinforcement, and mechanical properties of the groove-filling epoxy. One beam strengthened in shear with externally bonded FRP laminates was also tested for comparison purposes. All beams had a limited amount of internal steel shear reinforcement to simulate a real strengthening situation. Test results are presented and discussed in the paper.     

Enhancement of seismic performance of reinforced concrete columns with buckling-restrained reinforcement

Reinforced concrete (RC) columns with light confinement prevalent in developing countries exhibit low ductility with brittle shear failure, especially when buckling of longitudinal rebars takes place. This study applies the buckling restraining concept widely used in seismic resistant steel structures to reinforcing bars. Two RC columns 270 mm×300 mm in cross section with a height of 1200 mm and minimum (non-seismic) transverse reinforcement were tested under cyclic lateral loading. Buckling-restrained reinforcement was provided over the critical zone. The buckling-restraining casing effectively prevented buckling of slender vertical bars under a substantially high axial load level, resulting in a more ductile mode of failure with the evident formation of plastic hinge at the base of the column. Prior to gravity load collapse, the drift capacities and the degraded concrete shear capacities of the specimens were significantly increased compared to their counterparts without casings.     

植筋在建筑物加固改建中的应用

近年来，随着建筑科技的发展和国外先进技术的引进，植筋等新技术在工程改建加固中开始逐渐运用，并因其施工操作简单而应用的较为广泛。以某建筑物局部改建的工程实例，详细介绍了植筋技术在工程中的应用及施工方法，并指出了植筋过程中应注意的问题。该技术施工施工方便简单，适用于建筑物的加固与改造。     

Shear strengthening of reinforced concrete beams by means of vertical prestressed reinforcement

Strengthening reinforced concrete (RC) elements critical to shear with prestressed transversal reinforcement can be an efficient method to increase the shear resistance of structures, allowing the development of the full flexural capacity. However, research on the performance of this technique is very limited, and methods for designing the optimum amount of prestressed transversal reinforcement and assessing the retrofitted structure have not been produced yet. Nonlinear finite element models are an important tool regarding predicting the efficiency of these interventions. In this paper, a shear-sensitive fibre beam formulation is extended in order to account for the effects of unbonded vertical external prestressed reinforcement in the structural response of RC beams. The model is validated with experimental tests available in literature, succeeding in capturing the gain of shear strength brought by different strengthening solutions. A parametric study is performed to find the optimal quantity of transversal reinforcement that ensures flexural failure mechanism in a beam with insufficient internal shear reinforcement. The relative simplicity of the numerical model makes it suitable for engineering practice.     

配置HRB500钢筋的框架结构非弹性地震反应分析

为实现建筑行业的可持续发展,中国土木建筑工程界正在推广应用HRB500级高强钢筋,但是,以HRB500钢筋作为主要受力钢筋的混凝土结构的抗震性能研究还相对缺乏.该文按<混凝土结构设计规范>最新修订稿设计了3个配置不同强度钢筋的8度0.3 g区一级抗震等级的混凝土框架结构,并完成了该3个结构在多波输入下的非弹性地震响应分...     

浅析植筋技术在加固改造中的运用与质量控制

结合工程实例，介绍了植筋技术的加固原理、施工方法，总结了其施工质量控制关键点，并结合施工过程中植筋技术不可避免存在的不利因素，提出了几点建议，以尽量避免不利因素的影响。     

悬链线效应下钢筋与混凝土黏结锚固性能试验研究

为研究悬链线效应下锚固钢筋与混凝土之间的黏结破坏,以及在RC框架结构连续性倒塌过程中钢筋拉断和黏结失效的先后顺序,分析锚固长度、钢筋布置方式对黏结锚固性能的影响。将钢筋锚固于钢筋混凝土柱中,通过自制的自平衡加载装置,实现对框架结构梁端破坏而钢筋未拉断时形成悬链线受力机制的钢筋进行加载。试验结果表明：锚固钢筋与混凝土之间发生劈裂破坏,而锚固钢筋并没有被拉断,所以在RC框架结构抗倒塌设计中不宜采用直锚的锚固形式,而应该采用其他有效的锚固形式。此外,单排钢筋布置有利于提高锚固钢筋与混凝土之间的平均黏结应力,较双排钢筋布置下的约提高15%。