Design and Fatigue Behavior of Near-surface Mounted CFRP Bars for Shear Strengthening of RC Bridge Girders PDF Download

Author: Brandon Ang Johnson
Publisher:
ISBN:
Category : Carbon fiber-reinforced plastics
Languages : en
Pages : 213

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Book Description
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.

Author: Jacob Hans Goebel
Publisher:
ISBN:
Category : Carbon fiber-reinforced plastics
Languages : en
Pages : 0

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Book Description
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.

Author: Jacob Hans Goebel
Publisher:
ISBN:
Category : Carbon fiber-reinforced plastics
Languages : en
Pages : 119

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Book Description
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.

Author: Jacob Hans Goebel
Publisher:
ISBN:
Category :
Languages : en
Pages : 209

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Book Description
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.

Author: Hayder A. Rasheed
Publisher: CRC Press
ISBN: 1482235595
Category : Technology & Engineering
Languages : en
Pages : 246

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Book Description
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

Author: Abdeldjelil Belarbi
Publisher: Transportation Research Board
ISBN: 0309155312
Category : Architecture
Languages : en
Pages : 130

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Book Description
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.

Author: Michael Grantham
Publisher: CRC Press
ISBN: 1138027081
Category : Technology & Engineering
Languages : en
Pages : 838

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Book Description
The Concrete Solutions series of International Conferences on Concrete Repair began in 2003 with a conference held in St. Malo, France in association with INSA Rennes. Subsequent conferences have seen us partnering with the University of Padua in 2009 and with TU Dresden in 2011. This conference is being held for the first time in the UK, in association with Queen’s University Belfast and brings together delegates from 36 countries to discuss the latest advances and technologies in concrete repair. Earlier conferences were dominated by electrochemical repair, but there has been an interesting shift to more unusual methods, such as bacterial repair of concrete plus an increased focus on service life design aspects and modelling, with debate and discussion on the best techniques and the validity of existing methods. Repair of heritage structures is also growing in importance and a number of the papers have focused on the importance of getting this right, so that we may preserve our rich cultural heritage of historic structures. This book is an essential reference work for those working in the concrete repair field, from Engineers to Architects and from Students to Clients.

Author: American Society of Civil Engineers
Publisher:
ISBN:
Category : Civil engineering
Languages : en
Pages : 1264

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Book Description
Vols. 29-30 contain papers of the International Engineering Congress, Chicago, 1893; v. 54, pts. A-F, papers of the International Engineering Congress, St. Louis, 1904.

Author: Alper Ilki
Publisher: Springer Nature
ISBN: 3030881660
Category : Technology & Engineering
Languages : en
Pages : 2516

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Book Description
This volume highlights the latest advances, innovations, and applications in the field of FRP composites and structures, as presented by leading international researchers and engineers at the 10th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering (CICE), held in Istanbul, Turkey on December 8-10, 2021. It covers a diverse range of topics such as All FRP structures; Bond and interfacial stresses; Concrete-filled FRP tubular members; Concrete structures reinforced or pre-stressed with FRP; Confinement; Design issues/guidelines; Durability and long-term performance; Fire, impact and blast loading; FRP as internal reinforcement; Hybrid structures of FRP and other materials; Materials and products; Seismic retrofit of structures; Strengthening of concrete, steel, masonry and timber structures; and Testing. The contributions, which were selected by means of a rigorous international peer-review process, present a wealth of exciting ideas that will open novel research directions and foster multidisciplinary collaboration among different specialists.

Author: Laura M. Barker
Publisher:
ISBN:
Category : Anchorage (Structural engineering)
Languages : en
Pages : 239

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Book Description
Large numbers of reinforced concrete deck girder (RCDG) bridges were built during the highway infrastructure boom of the 1950's. The advent of standardized deformed steel reinforcing bars during this time allowed for straight bar terminations in flexural tension regions. Designers of the time terminated reinforcing bars where they were no longer required by calculation and did not account for additional demands from the combination of shear and flexure. The design provisions of the time allowed higher shear stresses in the concrete than allowed in standards today which reduced the required quantity of transverse reinforcing steel. In addition, heavier trucks and higher traffic volumes on roadways today have greatly increased the service loading on these bridges. Engineers evaluating these older RCDG bridges often determine unsatisfactory load ratings due to flexural anchorage deficiencies in the girders, especially when the influence of shear is considered. These deficiencies result from inadequate capacity compared to current design standards due to poor cutoff details used in the initial design. Strengthening methods are necessary because comprehensive replacements of the large number of bridges are not economically feasible. Experimental research was conducted to evaluate the behavior of poorly detailed flexural anchorages and to develop methods to strengthen them. Realistic vintage girder specimens were constructed, retrofitted, instrumented, and tested to failure. The specimens reported in this thesis were full-scale inverted-T (IT) beams. Some of the specimens contained straight bar terminations crossing a preformed diagonal crack in the flexural tension region to investigate the influence of shear on the retrofit schemes. Instrumentation focused on measurement of the reinforcing steel stresses surrounding the diagonal crack and along the development length of the cutoff bars. Using results of past research to quantify the behavior of girders with straight-bar flexural anchorages in flexural tension regions, an innovative strengthening technique was developed using either near-surface mounted (NSM) stainless steel or titanium. Results from the NSM strengthening technique demonstrated the ability to delay or prevent flexural anchorage failures, with increased deformation capacities and increased strengths from 17% to 39% over baseline specimens. To show the success of this research and the immediate need for strengthened flexural anchorages, this research has already been implemented on a bridge in Mosier, Oregon. This groundbreaking research is described in detail in Appendix F.