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Effect of cathodic protection on bond strength between prestressing steel and concrete
Title
Effect of cathodic protection on bond strength between prestressing steel and concrete.
Creator
Ducrocq, Luc., Florida Atlantic University, Hartt, William H.
Abstract/Description
A series of experiments was performed on prestressed concrete specimens for the purpose of studying the tendency of disbonding between the embedded steel and the concrete due to an impressed cathodic current. The procedure first involved impressing an anodic current until active potentials were recorded along the tendon length. Subsequently, cathodic polarization of the prestressed tendons was affected using a current density of 1 mA/cm^2. The strain variation of the concrete specimens was...
Show moreA series of experiments was performed on prestressed concrete specimens for the purpose of studying the tendency of disbonding between the embedded steel and the concrete due to an impressed cathodic current. The procedure first involved impressing an anodic current until active potentials were recorded along the tendon length. Subsequently, cathodic polarization of the prestressed tendons was affected using a current density of 1 mA/cm^2. The strain variation of the concrete specimens was monitored during these two procedures using gages placed on the top or bottom surface. It was found that for a current density of 1 mA/cm^2 during the 30 day monitoring period the concrete relaxed by an amount equivalent to an 80 percent loss of bond between the tendons and concrete. The implications of this with regard to cathodic protection of prestressed concrete structures and components in actual service are discussed.
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Date Issued
1990
PURL
http://purl.flvc.org/fcla/dt/14591
Subject Headings
Prestressed steel construction, Prestressed concrete construction, Cathodic protection
Format
Document (PDF)
Hydrogen embrittlement of cathodically protected prestressing steel
Title
Hydrogen embrittlement of cathodically protected prestressing steel.
Creator
Kliszowski, Stanislas Henri., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Cathodic protection is currently recognized as the most practical mean for arresting corrosion of reinforcing steel tendons in existing concrete structures, however, its appropriateness in the case of prestressed concrete is questioned because prestressing steels are relatively susceptible to environmental cracking (hydrogen embrittlement). For the purpose of studying embrittlement tendencies a series of experiments using the slow strain rate technique were performed. The susceptibility to...
Show moreCathodic protection is currently recognized as the most practical mean for arresting corrosion of reinforcing steel tendons in existing concrete structures, however, its appropriateness in the case of prestressed concrete is questioned because prestressing steels are relatively susceptible to environmental cracking (hydrogen embrittlement). For the purpose of studying embrittlement tendencies a series of experiments using the slow strain rate technique were performed. The susceptibility to environmental cracking was compared for different steels corresponding to ASTM grades 270 and 250 polarized at $-$900 and $-1300$ mV (SCE) in deaerated saturated Ca(OH)$\sb2$ solutions. The influence of different notch and pit geometries was studied to simulate the behavior of corroded tendons and investigate the transition between smooth and severely notched specimen behavior. Also evaluated was the evolution of the mechanical properties of tendons after excessive polarization. The different cracking processes are discussed based on test data, fractography and exposures conditions associated with concrete structures.
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Date Issued
1994
PURL
http://purl.flvc.org/fcla/dt/14999
Subject Headings
Cathodic protection, Metals--Hydrogen embrittlement, Tendons (Prestressed concrete), Prestressed concrete--Deterioration, Prestressed steel construction
Format
Document (PDF)
Embrittlement susceptibility of corroded pre-stressing steel in concrete during cathodic polarization
Title
Embrittlement susceptibility of corroded pre-stressing steel in concrete during cathodic polarization.
Creator
Poeydomenge, Arnaud., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Experiments and analyses were performed to better define the limits of concern regarding hydrogen embrittlement in association with application of cathodic protection to prestressed concrete. To accomplish this, prestressed concrete specimens were locally corroded to different levels by anodic polarization and then polarized to -1.30 V SCE. A procedure of examination was developed using strain gauges to determine the level of prestrain. Relatively few brittle failures of wires resulted due,...
Show moreExperiments and analyses were performed to better define the limits of concern regarding hydrogen embrittlement in association with application of cathodic protection to prestressed concrete. To accomplish this, prestressed concrete specimens were locally corroded to different levels by anodic polarization and then polarized to -1.30 V SCE. A procedure of examination was developed using strain gauges to determine the level of prestrain. Relatively few brittle failures of wires resulted due, at least in part, to a relatively low prestrain of the pretensioned tendons. A model was developed which, coupled with data from parallel research, permitted definition of the minimum cross section for brittle failure as a function of the magnitude of prestrain and corrosion morphology of the wire. These results were tabulated in a format that can be used during field inspection to identify structural elements for which fracture could occur upon application of cathodic protection.
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Date Issued
1997
PURL
http://purl.flvc.org/fcla/dt/15417
Subject Headings
Prestressed concrete--Corrosion, Cathodic protection, Prestressed concrete--Embrittlement, Prestressed steel construction
Format
Document (PDF)
Centrally prestressed fiber reinforced concrete columns
Title
Centrally prestressed fiber reinforced concrete columns.
Creator
Grijalba, Daniel A., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description
With the need to improve corrosion resistance in columns and piles, the innovative idea of Centrally Prestressed Fiber Reinforced Concrete (CPFRC) columns is a promising solution. The first step is to compare if the compressive strength of any mix is affected by the size, geometry, or even the inclusion of polyolefin fibers in a specimen. The results showed that the cylinder size of 4 in. x 8 in., which is the most common size used by the testing labs, has the highest compressive strength....
Show moreWith the need to improve corrosion resistance in columns and piles, the innovative idea of Centrally Prestressed Fiber Reinforced Concrete (CPFRC) columns is a promising solution. The first step is to compare if the compressive strength of any mix is affected by the size, geometry, or even the inclusion of polyolefin fibers in a specimen. The results showed that the cylinder size of 4 in. x 8 in., which is the most common size used by the testing labs, has the highest compressive strength. There was no sign on compressive strength improvement with the use of polyolefin fibers, except for reduction in cracking size and concrete spalling. The second step compared the ultimate strength, ductility characteristics and failure mode of CPFRC columns to conventional columns. CPFRC showed adequate axial and flexural resistance, in addition to ductile behavior similar to regular reinforced concrete columns.
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Date Issued
2011
PURL
http://purl.flvc.org/FAU/3332253
Subject Headings
Prestressed concrete construction, Strength of materials, Composite reinforced concrete, Concrete, Chemical resistance
Format
Document (PDF)
Debond test of steel plate bonded with concrete exposed to harsh environment
Title
Debond test of steel plate bonded with concrete exposed to harsh environment.
Creator
Tharitimanont, Pattanaphol., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
This study presents the experimental and theoretical studies on debond of steel bonded to concrete, which aids in understanding the mechanics of the repaired damaged prestressed concrete girders with externally bonded steel plates. The bond strength of bonded steel plate specimen is determined experimentally by the debond test. The initial crack is introduced in the specimens at three different locations, which include the steel/adhesive interface, adhesive through-thickness, and adhesive...
Show moreThis study presents the experimental and theoretical studies on debond of steel bonded to concrete, which aids in understanding the mechanics of the repaired damaged prestressed concrete girders with externally bonded steel plates. The bond strength of bonded steel plate specimen is determined experimentally by the debond test. The initial crack is introduced in the specimens at three different locations, which include the steel/adhesive interface, adhesive through-thickness, and adhesive/concrete interface. Certain debond test specimens are exposed to freeze/thaw and tidal cycles to evaluate the degradation in bond strength resulting from the environmental conditions. The fracture toughness for debonding would be evaluated and expressed as the critical strain energy release rate. A finite element analysis was performed to evaluate the compliance and stress distribution in the debond test specimens. Also, stress distribution of repaired AASHTO prestressed concrete bridge girders with metal sleeve splice was also determined at the interface of steel and concrete.
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Date Issued
1999
PURL
http://purl.flvc.org/fcla/dt/15681
Subject Headings
Bridges, Concrete--Testing, Prestressed concrete construction, Finite element method, Concrete--Environmental testing
Format
Document (PDF)
Polyethylene duct cracking in post-tensioning tendons of Florida segmental bridges
Title
Polyethylene duct cracking in post-tensioning tendons of Florida segmental bridges.
Creator
Suarez, Jorge Alejandro, Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
For the purpose of investigating the cause of duct cracking in post-tensioning tendons and improving the durability of this type of structure, a series of experiments was performed. These were divided in two groups, the first to simulate the state of stress inside the tendon ducts and the second to compare the properties of new materials approved according to new regulations on the subject and those used in the construction of the structures. A proposed mechanism of cracking was studied and...
Show moreFor the purpose of investigating the cause of duct cracking in post-tensioning tendons and improving the durability of this type of structure, a series of experiments was performed. These were divided in two groups, the first to simulate the state of stress inside the tendon ducts and the second to compare the properties of new materials approved according to new regulations on the subject and those used in the construction of the structures. A proposed mechanism of cracking was studied and its validity verified. According to simulations performed on specimens that were fabricated and others developed by the finite element method, new major factors were found to explain the duct failure. Finally, a comparison of mechanical properties indicated a difference between virgin and aged materials.
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Date Issued
2003
PURL
http://purl.flvc.org/fcla/dt/13071
Subject Headings
Post-tensioned prestressed concrete construction, Bridges--Florida, Polyethylene
Format
Document (PDF)
Ultimate load, creep, shrinkage, and reliability studies of a precast single cell segmental bridge with external post-tensioning
Title
Ultimate load, creep, shrinkage, and reliability studies of a precast single cell segmental bridge with external post-tensioning.
Creator
Murugesh, Ganapathy., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
This dissertation is a study of a 1:3.5 scale model of an externally post-tensioned single cell segmental bridge model of the Long Key bridge. The behavior of the bridge system was evaluated in terms of deflections, strains, joint openings, etc. under static and ultimate load conditions. The precast segmental bridge was cast, assembled, and tested at the Department of Ocean Engineering, Florida Atlantic University for AASHTO HS20-44 truck loadings at typical locations. The study addressed the...
Show moreThis dissertation is a study of a 1:3.5 scale model of an externally post-tensioned single cell segmental bridge model of the Long Key bridge. The behavior of the bridge system was evaluated in terms of deflections, strains, joint openings, etc. under static and ultimate load conditions. The precast segmental bridge was cast, assembled, and tested at the Department of Ocean Engineering, Florida Atlantic University for AASHTO HS20-44 truck loadings at typical locations. The study addressed the joint opening behavior and the response of external tendons during service and ultimate load levels. The analytical nonlinear behavior of the bridge upto the ultimate load level has been predicted using a finite element software PCFRAME developed at University of California, Berkeley. Creep and shrinkage strains were predicted using computer program CRACK developed at University of Calgary, Canada. Creep and shrinkage coefficients evaluated from short term tests, were used in predicting the long term behavior. A method for reliability analysis of post-tensioned segmental bridges has also been presented for serviceability and ultimate limit state conditions.
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Date Issued
1991
PURL
http://purl.flvc.org/fcla/dt/14709
Subject Headings
Precast concrete construction--Testing, Post-tensioned prestressed concrete construction--Testing, Bridges, Concrete--Models
Format
Document (PDF)
Debond of CFRP laminate bonded with concrete exposed to harsh environmental conditions
Title
Debond of CFRP laminate bonded with concrete exposed to harsh environmental conditions.
Creator
Baker, William Arnold., Florida Atlantic University, Arockiasamy, Madasamy
Abstract/Description
This study evaluates the effectiveness of using externally bonded CFRP plates for repairing damaged prestressed concrete structures as an alternative to the metal sleeve splice. Currently the metal sleeve splice is the most often used method for the repair of damaged prestressed concrete bridges. The use of bonded CFRP plates could be a viable alternative to the use of steel in this type of repair because of their high strength and stiffness, resistance to corrosion and low weight. The bond...
Show moreThis study evaluates the effectiveness of using externally bonded CFRP plates for repairing damaged prestressed concrete structures as an alternative to the metal sleeve splice. Currently the metal sleeve splice is the most often used method for the repair of damaged prestressed concrete bridges. The use of bonded CFRP plates could be a viable alternative to the use of steel in this type of repair because of their high strength and stiffness, resistance to corrosion and low weight. The bond strength of CFRP plates bonded to concrete was evaluated by the use of a peel test and correlated by a finite element analysis. The peel test showed that the structural system was not significantly adversely effected by harsh environmental conditions. The results of this study showed that the use of CFRP plates is a feasible alternative to steel in the metal sleeve splice repair with some limiting factors.
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Date Issued
1999
PURL
http://purl.flvc.org/fcla/dt/15721
Subject Headings
Fiber reinforced plastics, Concrete--Environmental testing, Prestressed concrete construction--Maintenance and repair
Format
Document (PDF)
Feasibility studies on carbon fiber composite cables in reinforced/prestressed concrete structures
Title
Feasibility studies on carbon fiber composite cables in reinforced/prestressed concrete structures.
Creator
Kanneganti, Srikanth., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The feasibility studies on the use of non-metallic continuous fiber reinforcement in reinforced and prestressed concrete structures are presented herein. Experimental results from studies on relaxation, bond and transfer length of Carbon Fiber Composite Cables (CFCC) are presented followed by results of flexural load tests on concrete beams reinforced and prestressed with CFCC. Durability of the CFCC is another prime concern, and hence part of the study also focuses on establishing the...
Show moreThe feasibility studies on the use of non-metallic continuous fiber reinforcement in reinforced and prestressed concrete structures are presented herein. Experimental results from studies on relaxation, bond and transfer length of Carbon Fiber Composite Cables (CFCC) are presented followed by results of flexural load tests on concrete beams reinforced and prestressed with CFCC. Durability of the CFCC is another prime concern, and hence part of the study also focuses on establishing the durability of the CFCC exposed to aggressive environments like alkali solution and sea water. The basic mechanics that govern the structural behavior of the beams, provide important insight into the potential that CFCC has to offer.
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Date Issued
1994
PURL
http://purl.flvc.org/fcla/dt/15080
Subject Headings
Fiber reinforced plastics, Reinforced concrete, Fiber, Composite materials, Prestressed concrete construction--Deterioration, Carbon fibers
Format
Document (PDF)
Evaluation of the structural applicability of centrally prestressed, unreinforced concrete (CPUC) columns with modified Freyssinet hinges for marine and seismic environment
Title
Evaluation of the structural applicability of centrally prestressed, unreinforced concrete (CPUC) columns with modified Freyssinet hinges for marine and seismic environment.
Creator
Periyaiah, Rathinam., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
An innovative concept of the Centrally Prestressed, Unreinforced Concrete (CPUC) column with modified Freyssinet hinges formulated by Paul Csagoly, to prevent rebar corrosion and additionally mitigate seismic damage, was investigated. The first phase of this work emphasized the mode of failure, ultimate strength, and ductility characteristics of the CPUC columns. As expected, CPUC columns showed adequate axial and flexural resistance as well as ductility. The ultimate strengths of most of the...
Show moreAn innovative concept of the Centrally Prestressed, Unreinforced Concrete (CPUC) column with modified Freyssinet hinges formulated by Paul Csagoly, to prevent rebar corrosion and additionally mitigate seismic damage, was investigated. The first phase of this work emphasized the mode of failure, ultimate strength, and ductility characteristics of the CPUC columns. As expected, CPUC columns showed adequate axial and flexural resistance as well as ductility. The ultimate strengths of most of the CPUC columns were about 10 to 20% higher than those of conventional ones. The second phase dealt with an energy absorbing device compatible with CPUC column to meet the occasional high ductility demand of the CPUC columns in earthquake conditions. Hinges were tested for compressive strength and moment-rotation capability. Parametric studies of the hinges were conducted for different filler materials, and width-to-height ratios. The confined filler material in the Freyssinet type hinge was found to have excellent compressive strength and moment-rotation capability. The parameters, width-to-height ratios and different filler material, had significant effect on hinge's performance.
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Date Issued
1996
PURL
http://purl.flvc.org/fcla/dt/15253
Subject Headings
Columns, Concrete--Testing, Prestressed concrete construction--Testing, Strength of materials
Format
Document (PDF)
Feasibility of using carbon fiber reinforced plastic tendons in prestressed concrete Double-Tee bridge system
Title
Feasibility of using carbon fiber reinforced plastic tendons in prestressed concrete Double-Tee bridge system.
Creator
Zhuang, Ming., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
One of the major problems the construction industry faces today is corrosion of reinforcing and prestressing steel, which significantly affects the durability of concrete structures. Fiber reinforced plastics (FRPs) are highly regarded as prospective replacement for steel in prestressed concrete structures under corrosive environment. This investigation was conducted to establish the feasibility of using Carbon Fiber Composite (CFC) cables as reinforcing/prestressing elements in concrete...
Show moreOne of the major problems the construction industry faces today is corrosion of reinforcing and prestressing steel, which significantly affects the durability of concrete structures. Fiber reinforced plastics (FRPs) are highly regarded as prospective replacement for steel in prestressed concrete structures under corrosive environment. This investigation was conducted to establish the feasibility of using Carbon Fiber Composite (CFC) cables as reinforcing/prestressing elements in concrete bridge structures. Besides investigating durability of CFC cables and pretensioned concrete beams with CFC cables in adverse environments (alkali and seawater), flexure and shear tests were performed on single Double-Tee beams, together with service load behavior, fatigue strength and ultimate load capacity tests on a half scale model Double-Tee girder bridge system prestressed with CFC cables. Exposure to seawater and alkali environments has no adverse effect on the strength of the CFRP tendons as well as the pretensioned beams with CFRP. Based on the flexural strength tests on Double-Tee beams, the bond between CFRP tendons and concrete is satisfactory. The Double-Tee bridge system exhibited good fatigue resistance and adequate ductility under ultimate load conditions. The ultimate load capacity of the bridge is approximately three times the service load corresponding to two HS20-44 trucks and equals 2.4 times the first crack load. Finite element analyses were carried out to predict elastic deformations and collapse load of the Double-Tee bridge prestressed with CFC cables. Feasibility of using CFC cables in bridge structures is assessed based on the experimental and analytical parameters such as deflections, strains, crack distributions and crack widths.
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Date Issued
1996
PURL
http://purl.flvc.org/fcla/dt/12465
Subject Headings
Carbon fibers, Composite construction, Fiber reinforced plastics, Bridges, Iron and steel, Reinforced concrete construction, Prestressed concrete construction
Format
Document (PDF)
Behavior of precast single-cell segmental box bridges with external post-tensioning subjected to cyclic loading and temperature changes
Title
Behavior of precast single-cell segmental box bridges with external post-tensioning subjected to cyclic loading and temperature changes.
Creator
Sinha, Vikas., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The behavior of a precast single-cell segmental box bridge with external post-tensioning is studied based on a 1:3.5 scale model of the Long Key bridge in the Florida Keys. Constant amplitude fatigue loading was applied on the model at a critical location simulating HS20-44 AASHTO truck loading. The performance of the bridge model was evaluated in terms of deflections, strains in concrete and across the joints, and behavior of joints between the segments with increasing number of cycles of...
Show moreThe behavior of a precast single-cell segmental box bridge with external post-tensioning is studied based on a 1:3.5 scale model of the Long Key bridge in the Florida Keys. Constant amplitude fatigue loading was applied on the model at a critical location simulating HS20-44 AASHTO truck loading. The performance of the bridge model was evaluated in terms of deflections, strains in concrete and across the joints, and behavior of joints between the segments with increasing number of cycles of fatigue loading. Thermal response of the bridge model was also studied using finite element analysis and the predicted temperature distributions were compared with the experimental values.
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Date Issued
1991
PURL
http://purl.flvc.org/fcla/dt/14729
Subject Headings
Precast concrete construction--Fatigue, Post-tensioned prestressed concrete construction--Fatigue, Bridges, Box girder, Strains and stresses
Format
Document (PDF)
Microcomputer and exsysp based expert system for selection and design of retaining structures
Title
Microcomputer and exsysp based expert system for selection and design of retaining structures.
Creator
Sinha, Anuradha., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The automation of retaining structure selection and design by utilizing artificial intelligence tools is presented herein. The study involved the development of a microcomputer based expert system, RESTEX (REtaining STructure EXpert). The modules of the expert systems RETAININGEARTH, with M.1 knowledge base, and REFLEXYS have been updated and the resulting RESTEX modules are written in C using Exsys Professional for high speed and efficient utilization of memory. RESTEX is an interactive menu...
Show moreThe automation of retaining structure selection and design by utilizing artificial intelligence tools is presented herein. The study involved the development of a microcomputer based expert system, RESTEX (REtaining STructure EXpert). The modules of the expert systems RETAININGEARTH, with M.1 knowledge base, and REFLEXYS have been updated and the resulting RESTEX modules are written in C using Exsys Professional for high speed and efficient utilization of memory. RESTEX is an interactive menu-driven system consisting of modules for Structure Selection, Preliminary Design, Soils Classification, Stability Analysis, and Reinforcement Design. The system is capable of performing selection, analysis, and design of gravity walls, cantilever walls, counterfort walls, reinforced earth, gabion, cantilever and anchored sheet piles.
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Date Issued
1993
PURL
http://purl.flvc.org/fcla/dt/14937
Subject Headings
Precast concrete construction--Fatigue, Post-tensioned prestressed concrete construction--Fatigue, Bridges, Box girder, Strains and stresses
Format
Document (PDF)
Peel-off characteristics of carbon fiber laminates bonded to concrete
Title
Peel-off characteristics of carbon fiber laminates bonded to concrete.
Creator
Barbosa, Mauro., Florida Atlantic University, Arockiasamy, Madasamy
Abstract/Description
This study presents the experimental and theoretical studies on debond of carbon fiber laminates bonded to concrete, which aids in understanding the mechanics of the repaired damaged prestressed concrete girders with externally bonded carbon plates. The bond strength of carbon plate specimens bonded to concrete is determined experimentally by the debond test. The initial crack is introduced in the specimens at one location, namely the plate/adhesive interface. The fracture toughness for...
Show moreThis study presents the experimental and theoretical studies on debond of carbon fiber laminates bonded to concrete, which aids in understanding the mechanics of the repaired damaged prestressed concrete girders with externally bonded carbon plates. The bond strength of carbon plate specimens bonded to concrete is determined experimentally by the debond test. The initial crack is introduced in the specimens at one location, namely the plate/adhesive interface. The fracture toughness for debonding is evaluated and expressed as the critical strain energy release rate. A finite element analysis was performed to evaluate the compliance and stress distribution in the debond test specimens.
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Date Issued
2000
PURL
http://purl.flvc.org/fcla/dt/12669
Subject Headings
Prestressed concrete construction--Maintenance and repair, Fracture mechanics, Carbon composites
Format
Document (PDF)
role of polyethylene duct cracking in the failure of post-tensioned cables in Florida segmental bridges
Title
The role of polyethylene duct cracking in the failure of post-tensioned cables in Florida segmental bridges.
Creator
David, Florent Martin., Florida Atlantic University, Hartt, William H.
Abstract/Description
During the past several decades, segmental construction using precast sections has evolved as a preferred design and construction method for bridges. The tendons used to hold the precast sections together are comprised of cables surrounded by a plastic duct filled with grout. Cracking of the tendon's protective plastic duct has been observed in several Florida bridges. An experimental investigation was performed to characterize the material properties of the high density polyethylene ducts...
Show moreDuring the past several decades, segmental construction using precast sections has evolved as a preferred design and construction method for bridges. The tendons used to hold the precast sections together are comprised of cables surrounded by a plastic duct filled with grout. Cracking of the tendon's protective plastic duct has been observed in several Florida bridges. An experimental investigation was performed to characterize the material properties of the high density polyethylene ducts used in the past and those being specified nowadays. The degree of cure of the resin, the results of three-point bending tests for unnotched and notched specimens, the coefficient of thermal expansion, and the deformation of a tendon as a function of temperature changes were studied. The effects of the grouting pressure and the void presence in the grout were quantified and the pressurization period was shown to affect significantly the pipe strain.
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Date Issued
2003
PURL
http://purl.flvc.org/fcla/dt/12999
Subject Headings
Pipe, Plastic--Testing, Bridges--Florida, Post-tensioned prestressed concrete construction
Format
Document (PDF)
Static, fatigue and ultimate load behavior of bridges prestressed with advanced composite materials
Title
Static, fatigue and ultimate load behavior of bridges prestressed with advanced composite materials.
Creator
Sandepudi, Krishna Srinivasa., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
One of the major problems the construction industry faces today is low corrosion resistance of reinforcing and prestressing steel, which significantly affects the durability of concrete structures. Theoretically Advanced Composite Materials (ACM) can successfully be used in concrete structures, in lieu of steel, as reinforcing and/or prestressing elements, owing to high tensile strength, immunity towards corrosion, low Young's modulus, light weight and high fatigue resistance. Very little...
Show moreOne of the major problems the construction industry faces today is low corrosion resistance of reinforcing and prestressing steel, which significantly affects the durability of concrete structures. Theoretically Advanced Composite Materials (ACM) can successfully be used in concrete structures, in lieu of steel, as reinforcing and/or prestressing elements, owing to high tensile strength, immunity towards corrosion, low Young's modulus, light weight and high fatigue resistance. Very little experimental and performance data are available on the properties of ACM and their application in concrete structures. Thus, to ensure safety of the structures, accurate assessment and continuous performance monitoring of the ACM together with the structure have to be made with an option of active and/or passive structural control. This investigation is aimed to establish the feasibility of using Aramid Fiber Reinforced Plastic (AFRP) cables as reinforcing/prestressing elements in concrete bridge structures. Besides investigating the durability of the AFRP cables in adverse environments (alkali and seawater), static and ultimate load tests were performed on a Double-Tee beam and three rectangular beams together with static, fatigue and ultimate load tests on a half scale model Double-Tee bridge system prestressed with AFRP. The AFRP specimens exposed to alkali and seawater for 900 hours retained 88% of the average failure strength of control specimens. Large deformations at ultimate conditions and good fatigue resistance were observed in the experimental studies. A computer code, FRPFLEX, was developed to perform flexural analysis of beams prestressed/reinforced with the ACM. An incremental, stiffness augmented non-linear analysis was performed using grillage analogy to assess static flexural behavior of Double-Tee bridge system. Analytical results showed good correlation with experimental findings. An active deformation/vibration control model is suggested, which can be incorporated in prototype bridges for safety and performance data evaluation. Feasibility of the use of the AFRP cables in bridge structures is assessed based on the experimental and analytical parameters such as deflections, strains, crack distributions, crack widths and energy considerations.
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Date Issued
1995
PURL
http://purl.flvc.org/fcla/dt/12414
Subject Headings
Prestressed concrete construction, Steel--Fatigue, Bridges--Fatigue, Fiber reinforced plastics
Format
Document (PDF)
Theoretical analysis of reinforced and prestressed concrete bridge members strengthened with CFRP laminates
Title
Theoretical analysis of reinforced and prestressed concrete bridge members strengthened with CFRP laminates.
Creator
Qu, Rong., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Nonlinear finite element analyses of the reinforced rectangular beams, prestressed solid slab and prestressed voided slab retrofitted with CFRP laminates are carried out using the software ANSYS(version 5.0) on the Sunwork station. The computer analyses are based on the proposed stress-strain relationship considering the effects of tensile stress on both elastic modulus and maximum compressive stress of concrete. Several assumptions are made in predicting the loss of tensile strength due to...
Show moreNonlinear finite element analyses of the reinforced rectangular beams, prestressed solid slab and prestressed voided slab retrofitted with CFRP laminates are carried out using the software ANSYS(version 5.0) on the Sunwork station. The computer analyses are based on the proposed stress-strain relationship considering the effects of tensile stress on both elastic modulus and maximum compressive stress of concrete. Several assumptions are made in predicting the loss of tensile strength due to crack, confinement due to the laminate bonding, tensile strength due to the prestress force, failure pattern due to the concentrated stress adjacent to the loading point and concrete crushing due to large compressive strain. A subroutine is developed using macro commands of ANSYS. In this research, Branson's equation or Ie procedure is assumed in the prediction of deflection of retrofitted concrete members. The modifications needed due to laminate bonding are the cracking moments of inertia (Icr) of the beams or slabs bonded with CFRP laminates, which are included in the analysis.
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Date Issued
1994
PURL
http://purl.flvc.org/fcla/dt/15083
Subject Headings
ANSYS (Computer system), Reinforced concrete--Plastic properties, Carbon composites, Fiber reinforced plastics, Bridges--Design and construction, Prestressed concrete construction
Format
Document (PDF)