体外预应力碳纤维片材补强加固技术

对现有碳纤维片材加固技术进行了介绍,分析了现有碳纤维片材加固技术的缺陷,就体外预应力碳纤维片材补强加固技术进行了探讨,并证实了体外预应力碳纤维片材补强加固技术是一项值得研究发展的新技术。     

碳纤维布加固技术在工程中的应用

用碳纤维布取代钢板加固混凝土结构是近几年来国际上兴起的一门新技术,其主要是通过配套粘结材料将碳纤维片材粘贴于构件表面,使碳纤维片材承受拉力,并与混凝土变形协调、共同受力,起到对原混凝土结构加固补强的作用.     

碳纤维片材加固混凝土结构技术的研究现状及展望

使用碳纤维片材加固补强混凝土结构的新技术是土木工程界研究与应用的热点.本文较为详尽地介绍了碳纤维片材及配套树脂类粘结材料的性能、特点,在混凝土结构加固领域的应用及方法,综述了此种新型加固方法在国内外的研究及应用现状,并指出今后的发展趋势.     

浅谈桥梁CFRP加固技术

介绍了碳纤维材料的力学特性,分析了碳纤维片材对实际桥梁裂缝的抑制机理,阐述了碳纤维加固技术的特点及碳纤维补强加固的施工工艺,以推广CFRP加固技术在工程中的应用。     

碳纤维在桥梁加固中的应用

根据目前碳纤维增强材料（CFRP）加固混凝土的理论,论述了碳纤维片材粘贴到混凝土表面用于结构补强与加固的技术特点,对其抗弯承载力计算进行了分析,并介绍了碳纤维在桥梁加固工程中的应用。     

浅谈碳纤维质材料在结构加固中的作用

介绍了碳纤维的特点,分析了碳纤维布及配套树脂类粘结材料的性能,探讨了碳纤维片材在加固工程中的应用范围,并对碳纤维片材加固工程实例进行了说明,以推广碳纤维在钢筋混凝土加固工程中的应用.     

碳纤维片材加固混凝土结构施工应用分析

1前言 　　碳纤维增强聚合物(Carbon Fiber Reinforced Ploymer,简称CFRP)是一种新兴的高强材料,近年来在建筑工程领域的研究与应用得到了迅速发展.较之传统的结构加固方法,碳纤维加固技术是一种新型高效的加固修复技术,它具有高强、高效、施工便捷、使用面广等优点.其中碳纤维片作为一种新的混凝土结构加固修复技术其工法主要采用“三步法“,即分别用底层树脂、找平材料和浸渍树脂的双组份树脂粘结材料,将碳纤维片材粘贴在结构构件外表面,以达到加固补强的目的,目前除了在混凝土中应用以外,正逐渐推广到砌体结构、钢结构甚至木结构的加固修复当中.……     

温州火车站基本站台雨蓬加固与纠偏

本文介绍了站台雨棚应用锚杆静压桩及截柱顶升技术进行地基基础加固补强及其倾斜纠偏,采用碳纤维片材加固混凝土结构构件。     

碳纤维片材在旧桥加固中的应用

碳纤维片材加固修复混凝土结构是一项新的应用外粘高性能复合材料加固结构的技术。目前广泛应用于铁路公路桥梁、高架道路等构筑物的结构补强和抗震加固,亦可用于曲面及节点等复杂形式的加固。利用碳纤维优势的材料性能,代替构件的钢筋,增加构件的配筋量和刚度,从而提高构件的承载能力和提高构件的安全系数,延长构件的使用年限。     

碳纤维片材加固混凝土结构的施工工艺

碳纤维片材加固补强技术是近年来新兴的一门加固技术,是一项应用于外贴高性能复合材料加固的新技术,适用于钢筋混凝土结构的加固补强,施工便捷,无需大型施工机具,可任意剪裁,工期短,具有耐久性、耐腐蚀性和抗老化性强等特点,可用于混凝土梁、柱、楼板等的加固补强。其具体施工工艺如下。     

碳纤维增强塑料(CFRP)加固混凝土柱机理研究

介绍了碳纤维增强塑料的特点及其材料性能，并对CFRP加固混凝土柱的机理进行了分析论述，最后对今后的应用研究中需要解决的问题提出了建议，得出CFRP是一种新型的建筑材料，具有良好的发展前景。     

碳纤维布加固技术在吉家庄大桥修复补强工程中的应用

碳纤维材料具有强度高、密度小、耐腐蚀以及耐疲劳性能好等特点。针对吉家庄大桥火烧后的损伤情况,采用粘贴增强碳纤维布的方法对该桥进行了修复补强。碳纤维布加固既有混凝土桥梁结构技术是一种新兴的桥梁结构加固方法,它采用特种结构胶将碳纤维布粘贴在结构构件表面,从而起到对原结构的补强作用。通过对该桥采用碳纤维布加固处理后3年来的现场交通运营监测情况,碳纤维布的加固有效地提高了桥梁的承载能力,满足了该桥现有使用功能的需要。     

碳纤维加固对钢筋混凝土连续梁受力影响的初探

针对多跨框架建筑加固工程中常遇到无法对钢筋混凝土(RC)连续梁梁顶进行加固的情况，可以考虑采用碳纤维增强复合材料(CFRP)来加固梁的跨中，增强其正截面的抗弯承载力，并利用梁支座处出现塑性铰，引起弯矩重分布的特性，来达到加固之目的。本文主要对CFRP加固后，连续梁调幅能力、支座配筋率对加固效果影响、二次受力等几个因素可能对连续梁承载力产生的影响做了定性分析。     

碳纤维布加固钢筋混凝土梁的弯曲性能

对采用碳纤维布加固的钢筋混凝土梁的弯曲性能进行研究。考察了配筋率ρ对加固梁弯曲强度的影响。对12个混凝土梁试件(截面尺寸为宽150mm,高200mm,长2000mm)进行了试验。梁截面具有三种不同的纵向钢筋配筋率,9个试件在受弯区域采用碳纤维布加固,另外3个试件作为对比试件。不同试件中,碳纤维布的宽度、长度和层数是变化的。与对比试件相比,加固梁的弯曲强度和刚度增加了。从研究结果可得出,与最大配筋率的梁相比,ACI440·2R-02的设计指南和加拿大的I-SIS高估了碳纤维布在小配筋率梁的弯曲强度方面的增加作用。随着梁的配筋率ρ的增长,试验荷载与按照ACI440·2R-02指南和加拿大ISIS计算荷载的比值是增长的。因此,由两个设计指南提出的方程更适合于高配筋率的梁,接近最大配筋率ρmax的梁试件的破坏具有足够的延性。     

Truss-arch model for shear strength of seismic-damaged SRC frame columns strengthened with CFRP sheets

Carbon fiber reinforced polymer (CFRP) materials are important reinforcing substances which are widely used in the shear strengthening of seismic-damage steel reinforced concrete (SRC) frame structures. To investigate the shear strength of SRC frame columns strengthened with CFRP sheets, experimental observations on eight seismic-damaged SRC frame columns strengthened with CFRP sheets were conducted at Yangtze University and existing experimental data of 49 SRC columns are presented. Based on the existing experiments, the theories of damage degree, zoning analysis of concrete, and strengthening material of the column are adopted. To present the expression formula of the shear strength of SRC frame columns strengthened with CFRP sheets, the contributions of strengthening material and transverse reinforcement to shear strength in the truss model are considered, based on the truss-arch model. The contribution of arch action is also considered through the analysis of the whole concrete and that of the three zones of the concrete are also considered. The formula is verified, and the calculated results are found to match well with the experimental results. Results indicate that the proposed whole analysis model can improve the accuracy of shear strength predictions of shear seismic-damaged SRC frame columns reinforced with CFRP sheets.     

Punching shear strength of interior slab–column connections strengthened with carbon fiber reinforced polymer sheets

In this paper, punching shear strengthening of flat slabs using Carbon Fiber Reinforced Polymer (CFRP) sheets is studied. Fifteen specimens of reinforced concrete slabs were tested. Thirteen of them were strengthened by CFRP sheets and two specimens were kept as control specimens. Four of these strengthened specimens were tested under cyclic vertical loading. The width of CFRP sheets varied in different specimens. The CFRP sheets were located at the tension side of the slabs in two perpendicular directions. Vertical load was applied downward through a column stub using a hydraulic Jack. In all specimens, no rupture of CFRP sheets was observed. The test results showed that the use of CFRP sheet, in addition to steel reinforcing bars, as flexural reinforcement improves the punching shear strength of slabs. This improvement can be significant for the slabs made of high strength concrete and low steel reinforcement ratio. However, the improvement of punching shear strength due to FRP strengthening reduced under cyclic vertical loading. The test results were compared with the equations proposed by ACI 318 and BS 8110 Codes. The ACI Code underestimates the punching shear strength of slabs and this underestimation becomes more pronounced with the increase in the flexural reinforcement. The BS 8110 Code appropriately accounts for the effect of flexural reinforcement on punching shear strength of slabs. However, for the strengthened slabs, an equivalent reinforcement ratio should be used to include the effect of both steel and CFRP flexural reinforcement.     

Modeling of insulated CFRP-strengthened reinforced concrete T-beam exposed to fire

The use of Fiber Reinforced Polymer (FRP) has been established as one of the possible techniques to strengthen concrete beams in flexure and shear. Carbon Fiber Reinforced Polymer (CFRP) has been identified as the material of choice in civil infrastructure applications. The fire performance of such CFRP-strengthened members and their resistance to heat transfer and to various environmental exposure factors need to be investigated. In this paper, a detailed finite element model of a CFRP-strengthened reinforced concrete T-beam is developed. The model accounts for the variation in thermal and mechanical parameters of the beams’ constituent materials with temperature, including CFRP and insulation materials. Nonlinear time domain transient thermal-stress finite element analysis is performed using the commercial software ANSYS to study the heat transfer mechanism and deformation within the beam for fire conditions initiating at the bottom of the beam. To relate the simulation to an actual case, a reinforced concrete T-beam strengthened with CFRP and fire-tested by other investigators is modeled. The progression of temperature in the beam, CFRP, reinforcing steel, and along the CFRP–concrete interface is compared to the observed fire test data. Overall, the predicted temperature results are in good agreement with the measured ones. In addition, the mid-span deflection increases nonlinearly during the fire exposure time due to the increase in the total strain on the tension side of the beams and due to concrete cracking. Successful FE modeling of this structure provides an economical, alternative solution to expensive experimental investigations.     

CFRP加固木结构的研究现状

总结了国内外已有的CFRP加固木结构的资料,分析了CFRP加固木梁受弯承载力、受剪承载力和木柱受压承载力的研究成果,并提出需进一步研究的问题,对推广木结构的应用有着重要的意义。     

预应力CFRP加固钢结构技术初探

介绍了预应力CFRP加固钢结构技术特点以及施工工艺、预应力张拉技术、各种加固布置方案及设计计算原则等,并对预应力CFRP加固钢结构技术进行初步的研究探索。     

CFRP加固钢筋混凝土直剪承载力试验

设计15个外贴碳纤维增强复合材料(CFRP)的Z型试件进行直剪加载试验,试验参数包括直剪面钢筋配筋率（0.46%~1.2%）和CFRP加固率（0%~0.3%）。依据试验结果提出加固后钢筋混凝土直剪承载力预测表达式,并基于分量模型分析其加固机理。研究结果表明:直剪承载力随CFRP加固率增大而提高,提高幅度为6%~50%;相同CFRP加固率时,直剪承载力提高幅度随配筋率的增加而降低,承载力提高源于CFRP提供了附加的侧向夹紧力;当外贴CFRP和内埋直剪钢筋提供相等的侧向夹紧力时,两者对直剪承载力的贡献作用相近;所提出的承载力预测表达式具有较好的适用性。