Current Search: Prestressed concrete (x)
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- Title
- Driveability of concrete piles pretensioned with CFRP.
- Creator
- Gemmell, Thomas Scott., Florida Atlantic University, Arockiasamy, Madasamy
- Abstract/Description
-
Four concrete piles prestressed with Carbon Fiber Reinforced Plastics were cast, in which two piles were fabricated with CFRP transverse reinforcement. The remaining two were provided with transverse steel spiral reinforcement. The piles were designed according to Florida Department of Transportation (FDOT) guidelines. The Pile Driving Analyzer (PDA) was chosen as the primary data acquisition system for the pile driving due to its mobility, reliability and robustness based on the high...
Show moreFour concrete piles prestressed with Carbon Fiber Reinforced Plastics were cast, in which two piles were fabricated with CFRP transverse reinforcement. The remaining two were provided with transverse steel spiral reinforcement. The piles were designed according to Florida Department of Transportation (FDOT) guidelines. The Pile Driving Analyzer (PDA) was chosen as the primary data acquisition system for the pile driving due to its mobility, reliability and robustness based on the high frequency excitation. The Pre-driving analysis consisted of several stages. The estimated static bearing capacity of the experimental piles was first calculated followed by SPT sampling at the pile driving site to obtain the soil conditions. The percent skin and toe friction, ultimate capacities, driving system parameters, maximum displacements, energy, integrity, tensions and static capacity were determined prior to pile driving. The piles were then driven and the data from the pile driving compared with the analysis.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15496
- Subject Headings
- Concrete piling, Fiber reinforced plastics, Prestressed concrete
- Format
- Document (PDF)
- Title
- ACOUSTIC EMISSIONS TESTING OF PRESTRESSED CONCRETE IN AN ACCELERATED STATE OF CORROSION.
- Creator
- BABAKANIAN, RUBIK., Florida Atlantic University, Dunn, Stanley E.
- Abstract/Description
-
The acoustic emission (AE) testing reported herein was conducted on a large size prestressed concrete slab placed in contact with sea water in a state of electrically induced accelerated corrosion. AE signals were monitored and successfully analyzed in an attempt to evaluate the severity of the deformation process in the concrete as a result of the corrosion induced cracking. Several features of the AE data which were sensitive to the process were plotted to show the different levels of the...
Show moreThe acoustic emission (AE) testing reported herein was conducted on a large size prestressed concrete slab placed in contact with sea water in a state of electrically induced accelerated corrosion. AE signals were monitored and successfully analyzed in an attempt to evaluate the severity of the deformation process in the concrete as a result of the corrosion induced cracking. Several features of the AE data which were sensitive to the process were plotted to show the different levels of the cracking due to the corrosion. These were amplitude, counts and energy distributions, and event distribution with time. A location test was employed to find the source of the activities. The results of the amplitude distributions were found to have similar characteristics to those obtained from the reinforced concrete AE experiments performed at Florida Atlantic University (1,2). These tests can be easily applied to a field location for an early detection of the deformation process in the concrete structures.
Show less - Date Issued
- 1984
- PURL
- http://purl.flvc.org/fcla/dt/14230
- Subject Headings
- Prestressed concrete, Acoustic emission testing
- Format
- Document (PDF)
- 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.
Show less - 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)
- 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.
Show less - 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)
- 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.
Show less - Date Issued
- 1990
- PURL
- http://purl.flvc.org/fcla/dt/14591
- Subject Headings
- Prestressed steel construction, Prestressed concrete construction, Cathodic protection
- Format
- Document (PDF)
- Title
- APPLICABILITY OF CATHODIC PROTECTION IN PREVENTION OF CORROSION DAMAGE TO STEEL TENDONS IN PRESTRESSED CONCRETE (HIGH STRENGTH STEEL, HYDROGEN EMBRITTLEMENT, BRITTLE CRACKING).
- Creator
- SCANNELL, WILLIAM THOMAS., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
A series of experiments were performed on a single tendon in a prestressed concrete slab for the purpose of studying the susceptibility of the high strength steel to brittle fracture as a result of cathodic protection. The procedure first involved impressing an anodic current until active potentials were recorded along the tendon length. Subsequently, cathodic polarization of the midsection of the tendon to -1.3 V(SCE) was effected. After a prescribed time, the tendon was removed and...
Show moreA series of experiments were performed on a single tendon in a prestressed concrete slab for the purpose of studying the susceptibility of the high strength steel to brittle fracture as a result of cathodic protection. The procedure first involved impressing an anodic current until active potentials were recorded along the tendon length. Subsequently, cathodic polarization of the midsection of the tendon to -1.3 V(SCE) was effected. After a prescribed time, the tendon was removed and sectioned into 15 ern lengths. Each segment strand was then notched and strained to failure, in three-point bending, in order to determine any effect of cathodic protection on the mechanical properties of the material. Differences in average failure loads were compared to determine if a loss of load-bearing capacity and brittle fracture occurred due to hydrogen absorption.
Show less - Date Issued
- 1986
- PURL
- http://purl.flvc.org/fcla/dt/14324
- Subject Headings
- Prestressed concrete--Testing, Steel--Corrosion
- Format
- Document (PDF)
- Title
- Prestressing steel to concrete bond degradation due to cathodic polarization.
- Creator
- Joubert, Emmanuel., Florida Atlantic University, Hartt, William H.
- Abstract/Description
-
Experiments were conducted to evaluate occurrence of any deterioration of prestressing steel tendon to concrete bond as a consequence of cathodic polarization. Pretensionned concrete specimens were cathodically polarized with current densities ranging from 50 to 5000 m^2 of steel while exposed to a constant flow of natural sea water. The concrete and steel dimensional changes were monitored by strain gages mounted on the tendons and embedded in the concrete. Contractions of the steel of 25 to...
Show moreExperiments were conducted to evaluate occurrence of any deterioration of prestressing steel tendon to concrete bond as a consequence of cathodic polarization. Pretensionned concrete specimens were cathodically polarized with current densities ranging from 50 to 5000 m^2 of steel while exposed to a constant flow of natural sea water. The concrete and steel dimensional changes were monitored by strain gages mounted on the tendons and embedded in the concrete. Contractions of the steel of 25 to 50 percent of the initial tensioning were recorded after 17 to 36 MC/m^2 were transferred to the tendons on specimens polarized at the highest currents. This corresponds to 54 to 114 years of polarization at 10mA/m^2 if bond loss was solely dependent on the charge transfer. It was noticed that the smaller the current, the more the charge that was transferred before steel contraction began. These results imply that cathodic polarization should impose no threat to the prestressing steel-to-concrete bond on typical structures over their expected lifetime.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/15209
- Subject Headings
- Prestressed concrete, Steel--Corrosion, Cathodic protection
- Format
- Document (PDF)
- Title
- Feasibility study of a prestressed concrete double-tee bridge system for interstate highways.
- Creator
- Badve, Anil Pandurang., Florida Atlantic University, Reddy, Dronnadula V.
- Abstract/Description
-
This dissertation is a study of 1:3.5 scale model of a two-span transversely and longitudinally post-tensioned continuous double-tee bridge system, representing a target bridge of 70 ft. span. Theoretical analysis was carried out for comparison using different modelling techniques, such as isotropic and orthotropic material behavior, and the load distribution theory. Behavior of the bridge system was evaluated in terms of deflections, wheel load distributions, crack patterns and growth with...
Show moreThis dissertation is a study of 1:3.5 scale model of a two-span transversely and longitudinally post-tensioned continuous double-tee bridge system, representing a target bridge of 70 ft. span. Theoretical analysis was carried out for comparison using different modelling techniques, such as isotropic and orthotropic material behavior, and the load distribution theory. Behavior of the bridge system was evaluated in terms of deflections, wheel load distributions, crack patterns and growth with increasing number of cycles of fatigue loading. The precast model beams were assembled and tested at the Department of Ocean Engineering, Florida Atlantic University. AASHTO HS20-44 truck loading was simulated by applying constant amplitude fatigue loading at typical locations. The study established the feasibility and structural adequacy of the precast prestressed concrete double-tee concept for short and medium span interstate highway bridges for use in Florida and elsewhere.
Show less - Date Issued
- 1989
- PURL
- http://purl.flvc.org/fcla/dt/14513
- Subject Headings
- Prestressed concrete beams--Fatigue, Bridges, Concrete--Joints
- Format
- Document (PDF)
- Title
- FATIGUE BEHAVIOR OF JOINTS IN PRECAST PRESTRESSED CONCRETE DOUBLE TEE BRIDGE SYSTEM.
- Creator
- RAO, VENKATESWARA B., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The feasibility of the use of double-tee beams in a bridge system is examined by conducting tests on a 1:3.5 scale model of a two-span transversely and longitudinally post-tensioned continuous double-tee beam system. Constant amplitude fatigue loading was applied on the model at typical locations simulating HS 20-44 AASHTO truck loading. The behavior of the bridge system was evaluated in terms of deflections, wheel load distributions, crack growth and patterns with increasing number of cycles...
Show moreThe feasibility of the use of double-tee beams in a bridge system is examined by conducting tests on a 1:3.5 scale model of a two-span transversely and longitudinally post-tensioned continuous double-tee beam system. Constant amplitude fatigue loading was applied on the model at typical locations simulating HS 20-44 AASHTO truck loading. The behavior of the bridge system was evaluated in terms of deflections, wheel load distributions, crack growth and patterns with increasing number of cycles of fatigue loading. A finite element analysis of the bridge system was done using plate and beam elements and results compared with experimental values.
Show less - Date Issued
- 1986
- PURL
- http://purl.flvc.org/fcla/dt/14332
- Subject Headings
- Prestressed concrete beams--Fatigue, Bridges, Concrete--Joints
- Format
- Document (PDF)
- Title
- Experimental studies on flexural behavior of CFRP retrofitted concrete members.
- Creator
- Raghavachary, Sowrirajan., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The flexural behavior of rectangular concrete beams strengthened with externally bonded Carbon Fiber Reinforced Plastic (CFRP) laminates was studied by varying the number of plates bonded to their bottom tensile face. The increases in strength and stiffness of the beams provided by the bonded plates, over control beam without CFRP plates, were evaluated. Failure loads of the beams were determined by the ACI strain compatibility method using a FORTRAN software developed for this purpose. The...
Show moreThe flexural behavior of rectangular concrete beams strengthened with externally bonded Carbon Fiber Reinforced Plastic (CFRP) laminates was studied by varying the number of plates bonded to their bottom tensile face. The increases in strength and stiffness of the beams provided by the bonded plates, over control beam without CFRP plates, were evaluated. Failure loads of the beams were determined by the ACI strain compatibility method using a FORTRAN software developed for this purpose. The predicted collapsed load agrees reasonably well with the actual failure load. Precracked solid and voided slab bridge models retrofitted with varying number of CFRP laminates were used to evaluate their contribution to the flexural resistance. The increases in strength and stiffness of the retrofitted slabs were based on the deflections, strains and crack patterns at ultimate load. Theoretical analyses to predict the load-deflection behavior of the precracked sections were performed using PCFRAME software. The predicted values agree reasonably well with the experimental results.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/15120
- Subject Headings
- Fiber reinforced plastics, Reinforced concrete, Fiber, Bridges, Concrete, Prestressed concrete, Concrete beams--Fatigue
- Format
- Document (PDF)
- Title
- Flexible Filler Corrosion Protection of Unbonded Post-Tension Tendons.
- Creator
- Castaneda, Carlos F., Presuel-Moreno, Francisco, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Flexible fillers has recently been implemented as corrosion protection for post-tensioning tendons used in bridge structures in Florida. There are two different explanations why corrosion could take place: 1. water is able to reach the steel 2. Microbiologica l ly Influenced Corrosion. The aim of this research is to evaluate corrosion protection effectiveness of five differe nt microcrystalline waxes under different environmental conditions. Specimens tested ranged from 7-wire steel strands...
Show moreFlexible fillers has recently been implemented as corrosion protection for post-tensioning tendons used in bridge structures in Florida. There are two different explanations why corrosion could take place: 1. water is able to reach the steel 2. Microbiologica l ly Influenced Corrosion. The aim of this research is to evaluate corrosion protection effectiveness of five differe nt microcrystalline waxes under different environmental conditions. Specimens tested ranged from 7-wire steel strands to single wires (12-16 cm). Another aim is the appraisal of wax degradation by fungi species. Single wires coated with each of the investigated protection materials, were sprayed with suspensions of three different fungi species and a mix of them. For single wires, independent of the environmental condition the specimen with more corrosion was Nontribos, as well as the filler coated wires contaminated with Fungi. Fungi species investigated were able to utilize the waxes as carbon source and caused differe nt extents of MIC.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004924, http://purl.flvc.org/fau/fd/FA00004924
- Subject Headings
- Nanocomposites (Materials), Polymeric composites., Post-tensioned prestressed concrete., Tendons (Prestressed concrete)
- Format
- Document (PDF)
- Title
- Non-destructive evaluation of corrosion-damaged pre-stressing steel in jacketed concrete piles.
- Creator
- Rapa, Martin Tymon., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
A study was performed for the purpose of developing a non-destructive method to evaluate corrosion damaged pre-stressing steel in jacketed concrete piles by using a cover meter. The procedure first involved taking cover meter readings with the pile jacket in place. Subsequently, a portion of the jacket was removed and tendon diameter measurements were taken. A relation for normalized tendon diameter as a function of normalized cover was determined, where normalized cover increased with a...
Show moreA study was performed for the purpose of developing a non-destructive method to evaluate corrosion damaged pre-stressing steel in jacketed concrete piles by using a cover meter. The procedure first involved taking cover meter readings with the pile jacket in place. Subsequently, a portion of the jacket was removed and tendon diameter measurements were taken. A relation for normalized tendon diameter as a function of normalized cover was determined, where normalized cover increased with a decrease in normalized tendon diameter. Finally, it is projected that the cover meter is a useful non-destructive tool to estimate the remaining tendon diameter in the inspection of jacketed, prestressed concrete piles and to this end to characterize the residual structural integrity of piles.
Show less - Date Issued
- 1998
- PURL
- http://purl.flvc.org/fcla/dt/15563
- Subject Headings
- Concrete piling, Prestressed concrete constuction--Corrosion, Prestressed steel constuction--Corrosion
- Format
- Document (PDF)
- 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.
Show less - 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)
- 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.
Show less - 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)
- Title
- Analytical and experimental studies on the static and fatigue behavior of precast prestressed concrete multibox beam bridge system.
- Creator
- Kozhikote, Ramkumar P., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The feasibility of the use of precast prestressed concrete multi-box beams with transverse post tensioning is examined for a medium span bridge system based on analytical and experimental studies on a 1:2.5 scale model. Constant amplitude fatigue loading was applied on the model at typical locations simulating HS20-44 AASHTO truck loading. The performance of the bridge system was evaluated in terms of deflections, strains in the concrete, wheel load distribution, and behavior of longitudinal...
Show moreThe feasibility of the use of precast prestressed concrete multi-box beams with transverse post tensioning is examined for a medium span bridge system based on analytical and experimental studies on a 1:2.5 scale model. Constant amplitude fatigue loading was applied on the model at typical locations simulating HS20-44 AASHTO truck loading. The performance of the bridge system was evaluated in terms of deflections, strains in the concrete, wheel load distribution, and behavior of longitudinal joints with increasing number of cycles of fatigue loading. A grillage analysis of the bridge system was carried out to predict the elastic behavior and the cracking moments and the results compared with the experimental values.
Show less - Date Issued
- 1989
- PURL
- http://purl.flvc.org/fcla/dt/14512
- Subject Headings
- Prestressed concrete beams--Fatique, Bridges, Box girder, Box beams
- Format
- Document (PDF)
- 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.
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fcla/dt/13071
- Subject Headings
- Post-tensioned prestressed concrete construction, Bridges--Florida, Polyethylene
- Format
- Document (PDF)
- Title
- Cathodic polarization and protection of simulated prestressed concrete pilings in sea water.
- Creator
- Pangrazzi, Richard., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Experiments were conducted to determine the effectiveness of cathodic polarization on simulated concrete piles containing unstressed continuous and segmented tendons exposed to sea water. Conductive rubber was used as anode material. Corrosion of the steel was enhanced by admixturing calcium chloride during concrete pouring. The specimens were cathodically polarized at constant potentials ranging from -0.72 to -1.10 V(sce). Current on and instant off potentials were monitored along the...
Show moreExperiments were conducted to determine the effectiveness of cathodic polarization on simulated concrete piles containing unstressed continuous and segmented tendons exposed to sea water. Conductive rubber was used as anode material. Corrosion of the steel was enhanced by admixturing calcium chloride during concrete pouring. The specimens were cathodically polarized at constant potentials ranging from -0.72 to -1.10 V(sce). Current on and instant off potentials were monitored along the specimen height at different water levels. The four hour potential decay criterion was used to determine if cathodic polarization was effective. Protection was achieved at locations where instant-off potentials were more negative than -0.79 V(sce). Polarization was never obtained above the anode. Also, the possibility of protecting a structure containing discontinuous steel was investigated. The results are discussed within the context of protecting actual marine pilings from corrosion.
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14699
- Subject Headings
- Concrete piling--Corrosion, Prestressed concrete--Corrosion, Reinforcing bars--Cathodic protection
- Format
- Document (PDF)
- Title
- Analytical studies of concrete double-tee bridge system prestressed with FRP materials.
- Creator
- Qiao, Pizhong., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The finite element analyses of the concrete bridge system and single double-tee beams are carried out using both orthotropic and isotropic modeling including linear and nonlinear behavior. The orthotropic concrete double-tee bridge system is modeled to predict the deformational behavior of bridge deck under the AASHTO service loading conditions in the static regimes. The nonlinear analyses of reinforced and prestressed concrete rectangular beams are also carried out to verify the validity of...
Show moreThe finite element analyses of the concrete bridge system and single double-tee beams are carried out using both orthotropic and isotropic modeling including linear and nonlinear behavior. The orthotropic concrete double-tee bridge system is modeled to predict the deformational behavior of bridge deck under the AASHTO service loading conditions in the static regimes. The nonlinear analyses of reinforced and prestressed concrete rectangular beams are also carried out to verify the validity of modeling. Both the linear and nonlinear finite element analyses for single double-tee beams prestressed with FRP materials are carried out in this study. In this research, the MARC finite element software on the VAX frame is used as a tool to carry out the analyses.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14936
- Subject Headings
- Finite element method, Fiber reinforced plastic, Bridges, Concrete--Floors, Prestressed concrete beams
- Format
- Document (PDF)
- 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.
Show less - 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)
- 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
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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.
Show less - 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)