Download or read book Strength and Durability of Near surface Mounted CFRP Bars for Shear Strengthening Reinforced Concrete Bridge Girders written by Jacob Hans Goebel and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the interstate expansion of the 1950s, many conventionally reinforced concrete deck girder bridges were built throughout the country. These aging bridges commonly exhibit diagonal cracking and rate inadequately for shear, thus they are candidates for shear strengthening to extend their useful life. Carbon fiber reinforced polymers (CFRP) are emerging as effective materials for strengthening and rehabilitating such bridges. Near surface mounting (NSM) is a newer technique for application of CFRP for retrofitting bridge members that provides advantages over other strengthening techniques. The technique is still new and uncertainties remain regarding strength, long-term durability, and design including the influence of member proportions, flexural reinforcing steel, and CFRP spacing. Bridge girders retrofitted with NSM-CFRP may be exposed to millions of load cycles and environmental conditions and the influence of these exposures on performance are not established. To address these issues, laboratory tests were performed on ten full-size reinforced concrete girders, representative of in-situ bridge members, to determine the performance of NSM-CFRP retrofitting for shear strengthening. One of the specimens was exposed to fatigue loading, two were subjected to environmental exposures, and one was subjected to combined environmental exposure and fatigue loading. Results indicated that NSM-CFRP retrofitting provided significant shear capacity increases, and the high-cycle fatigue and environmental exposures considered did not adversely affect the strength or behavior of the girders. Environmental exposures of some of the adhesives considered did show somewhat reduced performance; therefore, careful selection of materials is important to ensure performance over the expected lifetime. Recommendations for shear strength design with NSM-CFRP are made.

Download or read book Strength and Durability of Near surface Mounted CFRP Bars for Shear Strengthening Reinforced Concrete Bridge Girders written by Jacob Hans Goebel and published by . This book was released on 2012 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the interstate expansion of the 1950s, many conventionally reinforced concrete deck girder bridges were built throughout the country. These aging bridges commonly exhibit diagonal cracking and rate inadequately for shear, thus they are candidates for shear strengthening to extend their useful life. Carbon fiber reinforced polymers (CFRP) are emerging as effective materials for strengthening and rehabilitating such bridges. Near surface mounting (NSM) is a newer technique for application of CFRP for retrofitting bridge members that provides advantages over other strengthening techniques. The technique is still new and uncertainties remain regarding strength, long-term durability, and design including the influence of member proportions, flexural reinforcing steel, and CFRP spacing. Bridge girders retrofitted with NSM-CFRP may be exposed to millions of load cycles and environmental conditions and the influence of these exposures on performance are not established. To address these issues, laboratory tests were performed on ten full-size reinforced concrete girders, representative of in-situ bridge members, to determine the performance of NSM-CFRP retrofitting for shear strengthening. One of the specimens was exposed to fatigue loading, two were subjected to environmental exposures, and one was subjected to combined environmental exposure and fatigue loading. Results indicated that NSM-CFRP retrofitting provided significant shear capacity increases, and the high-cycle fatigue and environmental exposures considered did not adversely affect the strength or behavior of the girders. Environmental exposures of some of the adhesives considered did show somewhat reduced performance; therefore, careful selection of materials is important to ensure performance over the expected lifetime. Recommendations for shear strength design with NSM-CFRP are made.

Download or read book Design and Environmental Performance of Near surface Mounted Carbon Fiber Reinforced Polymer Strips for Shear Strengthening Reinforced Concrete Bridge Girders written by Jacob Hans Goebel and published by . This book was released on 2011 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the interstate expansion of the 1950s, many conventionally reinforced concrete deck girder bridges were built throughout the country. These now vintage bridges commonly exhibit diagonal cracking and rate inadequately for shear, thus they are candidates for shear strengthening to extend their useful life. Near-surface mounted (NSM) retrofitting is a promising new strengthening technique, but limited test data are available for carbon fiber reinforced polymer (CFRP) in shear strengthening making the long-term durability of NSM-CFRP unknown. This paper provides experimental results from realistic full-scale specimens strengthened with NSM-CFRP. Specimens were tested for shear strength and subjected to environmental exposures to assess long-term durability. Small cylinder specimens were tested to investigate relative performance of different adhesives on bond strength under different environmental exposures. Test results provide a better understanding of the NSM-CFRP shear behavior and strength. Recommendations for shear strength design with NSM-CFRP are made.

Download or read book Design and Fatigue Behavior of Near surface Mounted CFRP Bars for Shear Strengthening of RC Bridge Girders written by Brandon Ang Johnson and published by . This book was released on 2011 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon fiber reinforced polymer (CFRP) materials are emerging as an effective means of strengthening and rehabilitating bridges. Near surface mounting (NSM) is a newer technique for application of CFRP for retrofitting of bridge members that provides advantages over conventional strengthening techniques. The technique is still new and uncertainties remain regarding design including the influence of member proportions, flexural reinforcing steel, and CFRP spacing. Further, retrofitted girders may also be exposed to millions of cycles of loading after rehabilitation. It is not known if the effects of fatigue loading will affect the service life of the retrofitted member. To address these issues, laboratory tests were performed on eight full-size reinforced concrete girders, representative of in-situ bridge girders, to determine the performance of NSM-CFRP retrofitting for shear. Two of the specimens were exposed to fatigue loading. Results indicated that NSM-CFRP retrofitting provides significant shear capacity increases and exposure to fatigue cycling did not affect the strength or behavior of the specimens.

Download or read book Transforming Construction Advances in Fiber Reinforced Concrete written by Viktor Mechtcherine and published by Springer Nature. This book was released on with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cost effective Practices for Off system and Local Interest Bridges written by F. W. Klaiber and published by Transportation Research Board. This book was released on 2004 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 327: Cost-Effective Practices for Off-System and Local Interest Bridges examines off-system bridge design, construction, maintenance, financing, rehabilitation, and replacement. For this report, 'off-system' refers to those bridges typically owned and maintained by local agencies, and by state agencies on rural and other low-volume roads.

Download or read book Strengthening Design of Reinforced Concrete with FRP written by Hayder A. Rasheed and published by CRC Press. This book was released on 2014-12-16 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Strengthening Design of Reinforced Concrete with FRP establishes the art and science of strengthening design of reinforced concrete with fiber-reinforced polymer (FRP) beyond the abstract nature of the design guidelines from Canada (ISIS Canada 2001), Europe (FIB Task Group 9.3 2001), and the United States (ACI 440.2R-08). Evolved from thorough cla

Download or read book Environmental Durability of Reinforced Concrete Deck Girders Strengthened with Surface bonded Carbon Fiber reinforced Polymer written by Gautam Jayant Sopal and published by . This book was released on 2009 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: Long-term durability of surface-bonded carbon fiber-reinforced polymer (CFRP) for shear strengthening of reinforced concrete (RC) bridge members remains uncertain due to the limited field experience with these materials. This paper provides experimental results from the testing of full-scale RC bridge girder specimens after exposure to prolonged environmental exposure and combined action of freeze-thaw + repeated service loads. CFRP shear contributions seen in experimental results were estimated using a refined base capacity prediction (Response-2000) and compared to predicted CFRP shear contributions (ACI-440). The IT specimens did not exhibit strength reductions due to moisture exposure, instead the presence of continuous water exposure for the relatively young concrete caused higher concrete tensile properties resulting in increased bond strength. Previous research showed CFRP strengthened T specimens with freeze-thaw exposure exhibited lower shear capacity than similar unexposed CFRP strengthened T specimen. But the current research demonstrated that if the beam is well protected against moisture infiltration at the strip termination, the beam will be less susceptible to freeze-thaw bond deterioration. The orientations of specimens during repair and during exposure are important considerations for environmental durability. The CFRP strip terminations should be focused on during installation to insure well and perhaps extra saturation even past the CFRP material to limit moisture infiltration along this edge.

Download or read book Design of FRP Systems for Strengthening Concrete Girders in Shear written by Abdeldjelil Belarbi and published by Transportation Research Board. This book was released on 2011 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Report 678: Design of FRP Systems for Strengthening Concrete Girders in Shear offers suggested design guidelines for concrete girders strengthened in shear using externally bonded Fiber-Reinforced Polymer (FRP) systems. The guidelines address the strengthening schemes and application of the FRP systems and their contribution to shear capacity of reinforced and prestressed concrete girders. The guidelines are supplemented by design examples to illustrate their use for concrete beams strengthened with different FRP systems. Appendix A of NCHRP Report 678, which contains the research agency's final report, provides further elaboration on the work performed in this project. Appendix A: Research Description and Findings, is only available online.

Download or read book Effect of Flexural NSM FRP Bars on the Shear Strength of Reinforced Concrete Beams written by Rayyan Bashar Saleh and published by . This book was released on 2019 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Strengthening of reinforced concrete (RC) members in flexure and shear, using fiber-reinforced polymer (FRP) laminates and near surface mounted (NSM) bars has been developed over the last few decades. Conventionally, FRP composite laminates are attached to the vertical sides of RC beams to increase their shear strength. However, in some cases, the sides of the beam might be inaccessible or shallow. According to the ACI 318-14 guidelines and other codes of practice, longitudinal reinforcement contributes to the shear strength of RC beams. The objective of this study is to assess experimentally the effect of longitudinal NSM bars, which are mounted to the beam’s sides, on the shear strength of RC beams. The variables of the experimental program included the beam’s depth to evaluate the size effect, the concrete compressive strength, and the flexural FRP reinforcement ratio. A total of 18 shear deficient RC beams were built, strengthened with longitudinal NSM bars, and tested under three-point bending until failure. It was observed that the strengthened beam specimens exhibited an increase in shear capacity that ranged from 10 to 35% over the control beams. It was also observed that the increase in the concrete shear strength with longitudinal FRP bars for the high strength concrete specimens was not as effective as that with normal concrete strength specimens. The results have also revealed that the size effect phenomena has a significant effect on the test results, in which the increase in shear strength has decreased from around 35% to 10%, with the increase of beam's height from 230 to 650 mm, respectively. It was concluded that equation 22.5.5.1 of the ACI 318-14 code, which gives a simplified expression for the concrete contribution to the shear strength of beams, is not conservative for beams with large depths. Thus, other published analytical shear strength models that account for size effect were utilized in this study to predict the strength of the tested specimens. This study utilized 10 different analytical models in predicting the shear strength of the tested RC beam specimens. The models that showed the closest agreement with the tested data were the University of Houston method and the model based on the second order simplified modified compression field theory. It can be concluded that flexural longitudinal NSM bars could be used as a viable solution to enhance the shear strength of RC beams."--Abstract.

Download or read book Impact of Elevated Temperature Chemical and Workmanship on Performance of Beams with Near Surface Mounted FRP Bars written by Mahmoud Metwally Mohamed and published by . This book was released on 2017 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Near surface mounted (NSM) is growing exponentially into the strengthening and repair of concrete structures over the past decades worldwide. CFRP NSM offers a superior strength over conventional steel reinforcement as well as a good durability in various environmental service conditions. However, the effect of elevated temperature, adhesiveness and chemicals has not been sufficiently studied. This study aims at assessing the impact of elevated temperatures, adhesives, and chemicals on beams exposed to flexural loading. To meet this objective, a set of 60 beams were prepared with locally available NSM and exposed to temperatures of 70, 120 and 180 °C for 1, 2, 4 and 8 hours. Beams were also evaluated with three levels of adhesiveness placement and were also exposed to five weeks of wetting and drying in fresh water, brine water and magnesium Sulphate. The results of this work reveal that CFRP bars NSM mounted at a depth of 25 mm introduces more than double flexural strength of conventional steel reinforced beams. Exposure to different degree temperature at various duration, placement of adhesive and exposure to chemicals all lead to substantial drop in the flexural strength and thus affect the potential gain of NSM. This study should be resumed by future research work to validate the findings on one hand and to examine the effect of numerous other parameters. Construction industry needs to be aware of the findings of this work to make better use of its implementation in future repair and retrofitting. Keywords: (Near Surface Mounted, Fibre Reinforced Polymer, Repair and Retrofitting, elevated temperature, adhesive, chemicals).

Download or read book Strengthening of Reinforced Concrete Structures written by L C Hollaway and published by Elsevier. This book was released on 1999-03-05 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: The in situ rehabilitation or upgrading of reinforced concrete members using bonded steel plates is an effective, convenient and economic method of improving structural performance. However, disadvantages inherent in the use of steel have stimulated research into the possibility of using fibre reinforced polymer (FRP) materials in its place, providing a non-corrosive, more versatile strengthening system. This book presents a detailed study of the flexural strengthening of reinforced and prestressed concrete members using fibre reinforces polymer composite plates. It is based to a large extent on material developed or provided by the consortium which studied the technology of plate bonding to upgrade structural units using carbon fibre / polymer composite materials. The research and trial tests were undertaken as part of the ROBUST project, one of several ventures in the UK Government's DTI-LINK Structural Composites Programme. The book has been designed for practising structural and civil engineers seeking to understand the principles and design technology of plate bonding, and for final year undergraduate and postgraduate engineers studying the principles of highway and bridge engineering and structural engineering. Detailed study of the flexural strengthening of reinforced and prestressed concrete members using fibre reinforced polymer composites Contains in-depth case histories

Download or read book Seismic Performance of Corroded Reinforced Concrete Structures Retrofitted with FRP written by Dejian Shen and published by Springer Nature. This book was released on with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Recommended Guide Specification for the Design of Externally Bonded FRP Systems for Repair and Strengthening of Concrete Bridge Elements written by Abdul-Hamid Zureick and published by Transportation Research Board. This book was released on 2009 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Report 655: Recommended Guide Specification for the Design of Externally Bonded FRP Systems for Repair and Strengthening of Concrete Bridge Elements examines a recommended guide specification for the design of externally bonded Fiber-Reinforced Polymer (FRP) systems for the repair and strengthening of concrete bridge elements. The report addresses the design requirements for members subjected to different loading conditions including flexure, shear and torsion, and combined axial force and flexure. The recommended guide specification is supplemented by design examples to illustrate its use for different FRP strengthening applications.

Download or read book Methods for Strengthening Flexural Steel Details in Reinforced Concrete Bridge Girders Using a Near surface Mounted Retrofitting Technique written by Deanna Amneus and published by . This book was released on 2014 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many older reinforced concrete deck girder (RCDG) bridges contain straight bar terminations of flexural reinforcement. Common bridge design practice of the 1950s did not consider the additional demands on the terminated bars from shear and flexure. Moreover, more stringent code specifications and heavier permit trucks contribute to the insufficient ratings and presence of diagonal cracks in RCDG bridges. Replacement of these bridges is not economically feasible and thus strengthening methods are necessary. The goal of this research was to investigate anchorage strengthening methods using full-scale vintage girder specimens. The specimens were constructed with a flexural anchorage deficiency by terminating two flexural bars that extended only one-third of their development length past a 45° preformed diagonal crack. A common flexural strengthening technique called near-surface mounting (NSM) was applied to T-specimens. Two metallic materials were selected for the NSM reinforcement: titanium and stainless steel. These materials were chosen because of their high strength, ductility, environmental durability, and ability to fabricate mechanical anchorages. This study found that the NSM strengthening technique with metallic materials increased the midspan displacement by at least 85%, and load capacity by at least 31% for each specimen. In addition, a case study was performed to simulate the positive moment anchorage strengthening of the Mosier Bridge in Oregon.

Download or read book Synthesis of Highway Practice written by National Cooperative Highway Research Program and published by . This book was released on 2004 with total page 794 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Strengthening and Rehabilitation of Civil Infrastructures Using Fibre Reinforced Polymer FRP Composites written by L C Hollaway and published by Elsevier. This book was released on 2008-07-18 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: The repair of deteriorated, damaged and substandard civil infrastructures has become one of the most important issues for the civil engineer worldwide. This important book discusses the use of externally-bonded fibre-reinforced polymer (FRP) composites to strengthen, rehabilitate and retrofit civil engineering structures, covering such aspects as material behaviour, structural design and quality assurance. The first three chapters of the book review structurally-deficient civil engineering infrastructure, including concrete, metallic, masonry and timber structures. FRP composites used in rehabilitation and surface preparation of the component materials are also reviewed. The next four chapters deal with the design of FRP systems for the flexural and shear strengthening of reinforced concrete (RC) beams and the strengthening of RC columns. The following two chapters examine the strengthening of metallic and masonry structures with FRP composites. The last four chapters of the book are devoted to practical considerations in the flexural strengthening of beams with unstressed and prestressed FRP plates, durability of externally bonded FRP composite systems, quality assurance and control, maintenance, repair, and case studies. With its distinguished editors and international team of contributors, Strengthening and rehabilitation of civil infrastructures using fibre-reinforced polymer (FRP) composites is a valuable reference guide for engineers, scientists and technical personnel in civil and structural engineering working on the rehabilitation and strengthening of the civil infrastructure. Reviews the use of fibre-reinforced polymer (FRP) composites in structurally damaged and sub-standard civil engineering structures Examines the role and benefits of fibre-reinforced polymer (FRP) composites in different types of structures such as masonry and metallic strengthening Covers practical considerations including material behaviour, structural design and quality assurance