混凝土植筋设计理论及其在工程改造中的应用

介绍了混凝土植筋技术在钢筋达到设计强度、粘合剂与钢筋粘合界面达到限值、粘合剂与混凝土表面粘合达到限值三种情况下的破坏特征，给出了不同直径钢筋的实际锚固长度，指出混凝土植筋技术具有设计简单、施工便捷等特点。     

浅谈CGM钢筋锚固料的工程应用

植筋锚固在厂房改造和加固中有着广泛的应用,钢筋锚固料的选择对加固效果起到至关重要的作用。文中对比总结了常见钢筋锚固料的特性,介绍了CGM钢筋锚固料在工程应用中常见的问题及特点,提出解决问题的主要方法。     

梁体断裂原因分析及处理措施

分析了南京钢铁股份有限公司梁体断裂的原因,并根据现场情况,采用结构胶植筋锚固的方法,对平台进行了修复,满足了生产要求.     

栽植化学锚固螺栓在混凝土烟囱壁中的合理应用

栽植化学锚固螺栓简称“化学植筋”,它是通过在混凝土结构上钻孔,注入结构胶并将螺栓栽植到孔内,使构件满足结构受力要求的技术;本文对该项目技术在施工现场中的实际应用情况进行了介绍,可供同行借鉴。     

后锚固植筋技术在尾矿库浆砌石重力坝加高培厚工程中的应用

尾矿库浆砌石重力坝加高扩容工程与新建工程存在一些技术上的差异。结合红舍克尾矿库(北库)浆砌石重力坝加高培厚的工程实践,介绍了尾矿库浆砌石重力坝加高方式以及后锚固植筋技术在尾矿库浆砌石重力坝加高培厚工程中的应用,后锚固植筋技术的应用有效的解决了新老坝体连接、刚性坝排水以及温度应力场控制等问题,满足使用功能、环境保护和安全生产等要求。     

环氧砂浆锚固在310m~3高炉续建柱基中的应用

介绍了环氧砂浆锚固地脚螺栓技术移植到锚固螺纹钢筋的具体措施，以及使用后的情况。     

锈蚀植筋下新老混凝土黏结面压剪试验研究

为研究锈蚀植筋下新老混凝土的黏结性能,采用某工程锈蚀钢筋作为植筋,制备了不同植筋率（0、0.223%、0.446%、0.502%、0.893%、1.004%、1.396%、1.786%和2.792%）的新老混凝土试件.在RYL-600微机控制岩石伺服剪切流变仪上进行了不同初始静压力（0、1、2、3和4 MPa）下混凝土试件的剪切试验.对试件的剪应力-位移曲线进行了归纳总结,得到了锈蚀植筋下新老混凝土试件在外力作用下产生变形乃至破坏的演化规律;分析了锈蚀植筋下新老混凝土黏结面的抗剪强度,得到了抗剪强度随植筋率及初始静压力变化的规律.同时根据试件试验破坏结果,着重分析了不同植筋率和不同初始静压力对其破坏模式的影响.试验结论为新老混凝土力学性能的研究提供了理论依据.      

关键块体系统锚固法在加固边坡危岩中的应用

基于Goodman-Shi的块体理论和A.R.Yarahmadi Bafg hi的关键块体群理论,提出确定危岩边坡关键块体和关键块体系统的几何分析法和矢量分析法,建立边坡危岩的地质模型和力学模型,分析危岩体破坏机理,针对不同变形破坏机理的关键块体系统提出合理、安全和经济的危岩边坡加固新方法--关键块体系统锚固法(KSA法).通过建立集丹公路K49+790 m-K55+550 m段危岩边坡的地质模型和力学模型,结合其坡体及岩体结构特征,分析边坡危岩体变形破坏机理和锚固机理,提出顶部危岩清除,碎裂结构坡面喷射混凝土,块裂结构坡面挂网和块状岩体锚固的清-喷-网-锚联合锚固的系统锚固方案,加固该段危岩体.运用该法锚固方案较传统方法节省锚杆35%、SNS网32%及腰梁19%.     

自制LYQ—Y穿心式液压千斤顶的应用

自制锚杆锚固力测定机具ＬＹＱ－６穿心式液压千斤顶具有重量轻，体积小，测量精度高，操作方便，能快速准确的测出锚杆支护的锚固力。在本钢南芬露天铁矿爆破施工中使用效果良好。     

露天矿锚固边坡突变失稳初探

阐述了露天矿锚固边坡突变失稳的主控因素,应用突变理论来研究锚固边坡突变失稳的力学过程,建立了尖点突变模型。结果表明,锚固边坡系统发生突变失稳的条件是其系统的总势能,且爆破震动、水动力等因素的作用促使锚固边坡系统发生突变失稳。     

Three-Dimensional Modeling of Anchorage Zones in Reinforced Concrete

A model describing the bond between deformed reinforcement bars and concrete was developed, which considers the splitting stresses of the bond action. The model was previously verified against pullout tests of various geometries. In this study it is used in 3D finite-element analyses of different anchorage situations. One application was lapped reinforcement splices in beams and in frame corners. Another application was bars anchored in beam-ends with varying support conditions. When no additional confinement from the support reaction was present, splitting cracks appeared that reduced the anchorage capacity both in the analyses and in the tests. Analyses and tests of the anchorage at end regions of simply supported beams showed that the main part of the tensile force transfer between reinforcement and concrete takes place above or close to the support. It can be concluded that the bond model could describe the behavior of the different anchorage situations for both normal- and high-strength concrete in a satisfactory way, and thus can be used for further studies of different anchorage situations.     

Experimental Investigation on Seismic Retrofitting of Square RC Columns by Carbon FRP Sheet Confinement Combined with Transverse Short Glass FRP Bars in Bored Holes

Jacketing is less effective to large square/rectangular RC columns due to the inability of the rectangular-shaped jacket in restraining the dilation of concrete in the middle of a straight side. A new retrofit method is proposed in this work by fiber reinforcing the surface concrete in the middle of a straight side. Fiber reinforcing is achieved by inserting small fiber-reinforced polymer (FRP) bars into the concrete in the plastic hinge zone. The inserted FRP bars act as horizontal reinforcement to increase the ductility of the concrete in a similar way as that in normal fiber-reinforced concrete. When this fiber reinforcing technique is combined with the conventional jacketing, the concrete in all parts of a cross section may be effectively confined. In this work, experimental tests were undertaken to investigate the effectiveness of this new retrofit technique. Six half-scaled columns were tested and the test results demonstrated the effectiveness of the method.     

喷射混凝土在建筑物梁柱补强中的应用

喷射混凝土具有较高的强度和耐久性，与已施工的混凝土和钢筋具有强的粘结力，可用于建筑物梁柱的补强作业。     

Influence of Reinforcing Bars on Shrinkage Stresses in Concrete Slabs

It is well known that cracking in concrete slabs significantly influences their service life. Concrete shrinkage may be the principle reason for the initial crack formation in the slabs. This paper presents an attempt to provide an analytical tool for the prediction of stress distribution in reinforced concrete slabs after undergoing matrix shrinking restrained by the reinforcing bars. The model incorporates the material parameters of the reinforcing bar and the concrete matrix, and it enables prediction of the stress development in concrete with time.     

钢筋混凝土结构工程钢筋用量控制措施

通过合理的结构体系,从控制结构计算,控制楼板设计等几个方面提出降低钢筋用量的措施.     

Durability of GFRP Reinforcing Bars Embedded in Moist Concrete

This paper presents mechanical, microstructural, and physical characterization of glass fiber-reinforced polymer (GFRP) bars exposed to concrete environment. GFRP bars were embedded in concrete and exposed to tap water at 23, 40, and 50°C to accelerate the effect of the concrete environment. The measured tensile strengths of the bars before and after exposure were considered as a measure of the durability performance of the specimens and were used for long-term properties prediction based on the Arrhenius theory. In addition, Fourier transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy were used to characterize the aging effect on the GFRP reinforcing bars. The results showed that the durability of mortar-wrapped GFRP bars and exposed to tap water was less affected by accelerated aging than the bars exposed to simulated pore-water solution. These results confirmed that the concerns about the durability of GFRP bars in concrete, based on simulated laboratory studies in alkaline solutions, do not properly correspond to the actual service life in concrete environments.     

建筑用钢筋优化刍议

我国钢筋种类繁多,强度偏低,部分钢筋延性太差,已难以适应混凝土结构发晨的需要。基于混凝土结构对受力钢筋的要求,从强度、延性、质量稳定性、锚固性能、施工适应性及经济等方面对现有钢筋进行了分析比较。根据我国国情及建筑市场的变化,提出了大力推广Ⅲ级钢筋及中高强钢丝钢绞线,发展小直径Ⅱ、Ⅲ级钢筋。优化或淘汰冷加工钢筋,发展与钢筋有关的配套技术等建议。     

高强钢筋在大气中的腐蚀试验研究

采用显微镜技术和腐蚀速度测量法研究S400、表面预淬火的S500、含钒的S500 3种钢筋暴露在大气中的抗腐蚀行为.同时还研究了在水泥水合作用过程中,水泥与钢筋之间的结合力对钢筋腐蚀的影响.实验结果表明,具有较高抗大气腐蚀能力的钢筋类型是含钒的S500.相反,抗腐蚀能力最小的是表面预先淬火的S500钢筋.从ESEM观测到的形貌和钢筋表面的铁锈层的厚度结果看,钢筋与混凝土之间的结合力随侵蚀时间(从45天～122天)的延长而减小.     

Designing and Testing of Concrete Bridge Decks Reinforced with Glass FRP Bars

In addition to their high strength and light weight, fiber-reinforced polymer (FRP) composite reinforcing bars offer corrosion resistance, making them a promising alternative to traditional steel reinforcing bars in concrete bridge decks. FRP reinforcement has been used in several bridge decks recently constructed in North America. The Morristown Bridge, which is located in Vermont, United States, is a single span steel girder bridge with integral abutments spanning 43.90 m. The deck is a 230 mm thick concrete continuous slab over girders spaced at 2.36 m. The entire concrete deck slab was reinforced with glass FRP (GFRP) bars in two identical layers at the top and the bottom. The bridge is well instrumented at critical locations for internal temperature and strain data collection with fiber-optic sensors. The bridge was tested for service performance using standard truck loads. The construction procedure and field test results under actual service conditions revealed that GFRP rebar provides very good and promising performance.