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Title: THE INFLUENCE OF CATHODIC PROTECTION UPON CONSTANT DEFLECTION FATIGUE TESTS ON NOTCHED 1018 STEEL IN SEA WATER.
Creator: MARTIN, PHILIP EDWARD, Florida Atlantic University
Abstract/Description: Constant deflection fatigue experiments performed on cathodically protected, notched steel bars in natural sea water produced stresses which caused short cracks to appear soon after the beginning of testing . At stresses above 22 ksi (152 MN/m^2), cracks grew continuously across the bars. At stresses below 22 ksi (152 MN/m^2), and at potentials of -1.20 volts , saturated calomel electrode SCE, cracks did not grow, or arrested part way across the bar. At potentials other than - 1.20 volts ,...
Show moreConstant deflection fatigue experiments performed on cathodically protected, notched steel bars in natural sea water produced stresses which caused short cracks to appear soon after the beginning of testing . At stresses above 22 ksi (152 MN/m^2), cracks grew continuously across the bars. At stresses below 22 ksi (152 MN/m^2), and at potentials of -1.20 volts , saturated calomel electrode SCE, cracks did not grow, or arrested part way across the bar. At potentials other than - 1.20 volts , SCE, stress levels had to be less than 19 ksi (131 MN/m^2), before crack growth could be arrested. Strain gage readings suggest calcareous material may be forming on the fracture surfaces of cracks in which growth was arrested. Examination of these surfaces shows a pattern of calcareous deposit and corrosion product which suggests a potential gradient within the crack electrolyte. A mathematical model is presented which describes this potential gradient.
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Date Issued: 1979
PURL: http://purl.flvc.org/fcla/dt/13986
Subject Headings: Steel--Fatigue
Format: Document (PDF)

Title: FATIGUE CRACK DEVELOPMENT IN CATHODICALLY POLARIZED WELDED STEEL IN SEAWATER.
Creator: WEHLING, CHRISTOPHER MARK., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The fatigue crack growth behavior of welded ABS DH32 steel spec~mens cathodically polarized to -1.00 volt (Cu-CuS04) and subjected to bending fatigue of nominal stress + 69 MN/m^2 (+- 10 ksi) in seawater was investigated. Small non-propagating surface cracks with lengths up to 4.93 mm formed in the specimens. There were no s~gns of failure after 36 x 10^6 cycles when the experiment was terminated. Comparison of this test with similar freely corroding and -0.85 volt (Cu-CuS04) tests indicated...
Show moreThe fatigue crack growth behavior of welded ABS DH32 steel spec~mens cathodically polarized to -1.00 volt (Cu-CuS04) and subjected to bending fatigue of nominal stress + 69 MN/m^2 (+- 10 ksi) in seawater was investigated. Small non-propagating surface cracks with lengths up to 4.93 mm formed in the specimens. There were no s~gns of failure after 36 x 10^6 cycles when the experiment was terminated. Comparison of this test with similar freely corroding and -0.85 volt (Cu-CuS04) tests indicated that -1.00 volt (Cu-CuS04) cathodic protection is conducive to arrestment of small fatigue cracks. This suggests that modest cathodic over-protection of steel in seawater may beneficial.
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Date Issued: 1981
PURL: http://purl.flvc.org/fcla/dt/14091
Subject Headings: Steel--Fatigue
Format: Document (PDF)

Title: FATIGUE OF HIGH STRENGTH LOW-ALLOY STEELS IN NATURAL SEA WATER.
Creator: KRISHNAKUMAR, RENGAN., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The fatigue response of selected high strength low alloy steels, that are under consideration for future offshore structural applications, was investigated. Freely corroding and cathodically polarized experiments were conducted under conditions relevant .to these applications. Cathodic polarization experiments involved testing of A537 Direct Quenched (A537 DQ) steel at different potentials in the -0.80 V to -1.10 V (SCE) range. The damage to freely corroding high strength steel was more than...
Show moreThe fatigue response of selected high strength low alloy steels, that are under consideration for future offshore structural applications, was investigated. Freely corroding and cathodically polarized experiments were conducted under conditions relevant .to these applications. Cathodic polarization experiments involved testing of A537 Direct Quenched (A537 DQ) steel at different potentials in the -0.80 V to -1.10 V (SCE) range. The damage to freely corroding high strength steel was more than on structural steel for calculations based on the Wirsching wide band spectrum. Polarization to -0.80 V (SCE) improved the fatigue life of A537 DQ steel over the freely corroding life. A definite conclusion with regard to the influence of different levels of cathodic polarization on the fatigue life of the steel investigated can not not be drawn based on the results from this study due to data variability.
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Date Issued: 1987
PURL: http://purl.flvc.org/fcla/dt/14374
Subject Headings: Steel--Fatigue, Seawater
Format: Document (PDF)

Title: A FATIGUE STUDY OF HY-80 STEEL IN SEA WATER.
Creator: ADAMSON, JOHNNY DALE., Florida Atlantic University, Hartt, William H.
Abstract/Description: Fatigue tests were performed at low stresss intensity ranges upon precracxed HY-80 steel specimens in air and sea water, at stress ratios of 0.1 and 0.8 with and without cathodic protection. Crack growth. was found to be higher at R = 0.8 than R = 0.1. Also, the relative positioning of fatigue crack growth rate data for freely corroding and cathodically protected specimens reversed order cs R changed from 0.1 to 0.8. Threshold stress intensity ranges were found to be higher in sea water than...
Show moreFatigue tests were performed at low stresss intensity ranges upon precracxed HY-80 steel specimens in air and sea water, at stress ratios of 0.1 and 0.8 with and without cathodic protection. Crack growth. was found to be higher at R = 0.8 than R = 0.1. Also, the relative positioning of fatigue crack growth rate data for freely corroding and cathodically protected specimens reversed order cs R changed from 0.1 to 0.8. Threshold stress intensity ranges were found to be higher in sea water than in air. A comparison of the deltaKth for HY-80 was made with. that of other steels.
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Date Issued: 1979
PURL: http://purl.flvc.org/fcla/dt/13976
Subject Headings: Steel--Fatigue
Format: Document (PDF)

Title: Fatigue of high strength steels in sea water.
Creator: Sablok, Anil Kumar., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Fatigue response of selected high strength steels in seawater was investigated under conditions relevant to tension leg platform tendon applications. This involved both freely corroding and cathodically protected, displacement controlled experiments upon constant taper, bending specimens which were either notched or welded, ground and post weld heat treated. High stress range freely corroding results indicated enhanced life compared to structural steel, whereas at low stress range the...
Show moreFatigue response of selected high strength steels in seawater was investigated under conditions relevant to tension leg platform tendon applications. This involved both freely corroding and cathodically protected, displacement controlled experiments upon constant taper, bending specimens which were either notched or welded, ground and post weld heat treated. High stress range freely corroding results indicated enhanced life compared to structural steel, whereas at low stress range the opposite was true. Corrections made to the high strength steel and structural steel data to correspond to similar test conditions revealed no benefit of enhanced material strength on corrosion fatigue life. Fatigue life for all cathodically protected specimens exceeded that for the freely corroding ones, and with one exception testing was terminated prior to failure. The single cathodically protected specimen failure involved a stress range approximately one-third the value for other specimens which were run-outs. This suggests that an environmental cracking process may operate precipitously at relatively low stress amplitudes (alternately, high R values). Fatigue life for freely corroding notched specimens was less than for grounded PWHT specimens, the difference increasing with decreasing amplitude.
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Date Issued: 1988
PURL: http://purl.flvc.org/fcla/dt/14463
Subject Headings: Steel--Fatigue, Steel, High strength
Format: Document (PDF)

Title: STUDY OF THE WIDE-BAND SPECTRUM FATIGUE ON WELDED OFFSHORE STRUCTURES.
Creator: CHU, ZIN-HON., Florida Atlantic University, Hartt, William H.
Abstract/Description: In the present research butt welded ABS DH-32 steel specimens were fatigue tested under freely corroding and cathodic protection conditions by a time-series simulated wide-band spectra of a North Sea wave climate. Previous research pertaining to the probabilistic features of wave dynamics, wave force models, Markov-Chain sea state evolution and time-series simulation of wide-band spectra are addressed as a background review. The resulting freely corroding data are discussed on the basis of...
Show moreIn the present research butt welded ABS DH-32 steel specimens were fatigue tested under freely corroding and cathodic protection conditions by a time-series simulated wide-band spectra of a North Sea wave climate. Previous research pertaining to the probabilistic features of wave dynamics, wave force models, Markov-Chain sea state evolution and time-series simulation of wide-band spectra are addressed as a background review. The resulting freely corroding data are discussed on the basis of the SN plot which developed from the previous investigations at FAU. Calculation of the damage of failed specimens by employing the "Equivalent Narrow-Band Approach" resulted in excellent agreement with the linear damage summation assumption.
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Date Issued: 1985
PURL: http://purl.flvc.org/fcla/dt/14266
Subject Headings: Steel--Fatigue, Steel--Corrosion
Format: Document (PDF)

Title: INFLUENCE BY CALCAREOUS DEPOSITS ON FATIGUE CRACK CLOSURE IN STEEL.
Creator: LEE, AI-KUO., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A model for calcareous deposit induced fatigue crack closure has been previously reported based upon the criterion that the deposit thickness within the crack equals or exceeds one-half the minimum crack opening displacement. In the present paper an expanded and refined model is proposed by considering (1) compaction of calcareous deposits during the closure period of the stress cycle and (2) the relationship between R ratio and threshold stress intensity range. Compression tests upon...
Show moreA model for calcareous deposit induced fatigue crack closure has been previously reported based upon the criterion that the deposit thickness within the crack equals or exceeds one-half the minimum crack opening displacement. In the present paper an expanded and refined model is proposed by considering (1) compaction of calcareous deposits during the closure period of the stress cycle and (2) the relationship between R ratio and threshold stress intensity range. Compression tests upon calcareous films grown on steel surfaces have been performed, and these reveal the change in deposit thickness as a function of stress. The implications of these models to calcareous deposit induced fatigue crack closure are discussed in terms of mechanical and electrochemical parameters.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14315
Subject Headings: Steel--Fatigue, Steel--Corrosion
Format: Document (PDF)

Title: SIMULATED NORTH SEA SPECTRUM FATIGUE ON WELDED STEEL IN FLOWING SEA WATER.
Creator: Clark, A. M., Florida Atlantic University, Hartt, William H.
Abstract/Description: Reverse bend, uniform stress beam specimens of ABS DH-32 steel were subjected to fatigue cycles of randomly generated amplitude in a sea water environment to determine the effect of narrow band spectrum loading on cycles to failure. The loading spectrum was the C/12/20 spectrum, developed at the National Engineering Laboratory in Scotland to simulate the severe conditions of the North Sea. Some misinformation which has been published by NEL and other& regarding ~he C/12/20 spectrum is...
Show moreReverse bend, uniform stress beam specimens of ABS DH-32 steel were subjected to fatigue cycles of randomly generated amplitude in a sea water environment to determine the effect of narrow band spectrum loading on cycles to failure. The loading spectrum was the C/12/20 spectrum, developed at the National Engineering Laboratory in Scotland to simulate the severe conditions of the North Sea. Some misinformation which has been published by NEL and other& regarding ~he C/12/20 spectrum is addressed. A number ot means for presenting random amplitude cycles to failure data in the form of an SN plot are discussed. A means for taking into account fatigue test cycling rate in failure predictions is proposed, and the results of the freely corroding specimens of this investigation conform to the proposed technique. The random amplitude specimens exhibited reduced fatigue lives compared with similar specimens of an earlier constant amplitude investigation.
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Date Issued: 1983
PURL: http://purl.flvc.org/fcla/dt/14153
Subject Headings: Steel--Fatigue, Steel--Stress corrosion
Format: Document (PDF)

Title: Calcareous deposits in simulated fatigue cracks of cathodically protected steel in seawater.
Creator: Davidson, Keith Dewayne., Florida Atlantic University, Haratt, William H.
Abstract/Description: An experiment was designed to provide a simulated steel fatigue crack under cathodic protection in seawater for study. Calcareous deposits were found to form in the simulated crack at -0.800, -0.900, -1.000 and -1.100 volts (SCE) with cycle frequencies of both 0.5 and 1.0 Hertz. By X-ray and SEM analysis, calcium carbonate deposits were shown to grow in quantities sufficient to block and become compressed by this simulated crack. Increased fluid velocities from crack pumping were shown to...
Show moreAn experiment was designed to provide a simulated steel fatigue crack under cathodic protection in seawater for study. Calcareous deposits were found to form in the simulated crack at -0.800, -0.900, -1.000 and -1.100 volts (SCE) with cycle frequencies of both 0.5 and 1.0 Hertz. By X-ray and SEM analysis, calcium carbonate deposits were shown to grow in quantities sufficient to block and become compressed by this simulated crack. Increased fluid velocities from crack pumping were shown to negatively affect crystal nucleation and growth. Due to kinetic barriers to crystal growth, aragonite and brucite were determined to be the most likely deposit type; excluding calcite, dolomite and magnesite. The deposits formed at -1.000V were shown by current requirements and SEM to provide the best protection as a coating.
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Date Issued: 1988
PURL: http://purl.flvc.org/fcla/dt/14442
Subject Headings: Steel--Fatigue, Cathodic protection, Sea-water corrosion
Format: Document (PDF)

Title: Fatigue behavior of corrosion notched weathering steel samples.
Creator: Chen, Di, Granata, Richard D., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Weathering steel has been a primary construction material for bridges in the United States. Notches caused by corrosion are observed on the flange of steel I-beams. These notches reduce the cross section area of the structure and are threats to bridge safety. A606-04 Type 4 cold rolled weathering steel samples were studied in this thesis to understand the effect of notches that caused by corrosion. Weathering steel samples were in the shape of plates, which simulated flange of I-beams. The...
Show moreWeathering steel has been a primary construction material for bridges in the United States. Notches caused by corrosion are observed on the flange of steel I-beams. These notches reduce the cross section area of the structure and are threats to bridge safety. A606-04 Type 4 cold rolled weathering steel samples were studied in this thesis to understand the effect of notches that caused by corrosion. Weathering steel samples were in the shape of plates, which simulated flange of I-beams. The plate samples were notched across their surfaces by applying electrical current through an electrochemical circuit composed of an anode, a cathode and electrolyte. Sixteen samples were notched and cut into appropriate shape for fatigue testing. S-N (Stress-Number of cycles to failure) diagram established from fatigue data indicated that the fatigue strength decreased below AASHTO category B. Weibull analysis was also performed to understand the reliability distribution.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004092, http://purl.flvc.org/fau/fd/FA00004092
Subject Headings: Iron and steel bridges -- Corrosion, Protective coatings -- Evaluation, Reinforced concrete construction, Steel -- Fatigue, Steel, Structural -- Corrosion
Format: Document (PDF)

Title: Effect of cathodic protection and cyclic frequency on corrosion fatigue of selected high strength steels in seawater.
Creator: Badve, Ashwin P., Florida Atlantic University, Hartt, William H.
Abstract/Description: Study of selected candidate steels for offshore application was undertaken to observe the effects of cathodic protection and cyclic frequency on corrosion fatigue life. Keyhole Compact Tension Fatigue experiments under constant amplitude sinusoidal loading and stress ratio of 0.5 were performed on 25.4 mm thick specimens in natural sea water and also in air upon three different steels (Y.S. 500-563 MPa). These steels represented different strengthening techniques, namely precipitation...
Show moreStudy of selected candidate steels for offshore application was undertaken to observe the effects of cathodic protection and cyclic frequency on corrosion fatigue life. Keyhole Compact Tension Fatigue experiments under constant amplitude sinusoidal loading and stress ratio of 0.5 were performed on 25.4 mm thick specimens in natural sea water and also in air upon three different steels (Y.S. 500-563 MPa). These steels represented different strengthening techniques, namely precipitation hardening, direct quenching--a thermomechanical control process (TMCP), and controlled rolling. Cathodic polarization was in the range between freely corroding and -1.10 Volts (SCE). The tests were performed at a frequency of 0.3 and 1.0 Hz. The results are presented in the S-N and potential versus cycles to initiation format. No effect of frequency (1.0-0.3 Hz) was observed at cathodic protection of -1.10 V (SCE). The steels showed an increase in fatigue life to an optimum potential, and excessive potentials were detrimental. The fatigue life in dry air was greater than in laboratory air (~50% RH).
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14494
Subject Headings: Marine steel--Fatigue, Offshore structures, Sea-water corrosion, Corrosion and anti-corrosives
Format: Document (PDF)

Title: CORROSION FATIGUE OF NOTCHED 1018 STEEL IN SEA WATER.
Creator: FLUET, JOSEPH E., JR., Florida Atlantic University, Hartt, William H.
Abstract/Description: A summary of some pertinent previous research by other authors is presented separately from the actual laboratory report. The report presents the results of air and corrosion fatigue tests which are. interpreted in terms of time to failure, crack growth history, and fracture mechanics techniques. In addition, the results of cathodic protection of corrosion fatigue tests are interpreted in terms of simple-design criteria, as well as relative to Critical Corrosion Rate Theory. One of the more...
Show moreA summary of some pertinent previous research by other authors is presented separately from the actual laboratory report. The report presents the results of air and corrosion fatigue tests which are. interpreted in terms of time to failure, crack growth history, and fracture mechanics techniques. In addition, the results of cathodic protection of corrosion fatigue tests are interpreted in terms of simple-design criteria, as well as relative to Critical Corrosion Rate Theory. One of the more significant results presented is the greater longevity of corrosion fatigue, as compared to air fatigue, notched specimens stressed within 10-15 KSI above the air endurance limit. Also, the potential required to cathodically protect such notched specimens is shown to be 50 mV lower than for comparable smooth specimens. Both phenomena are attributed in part to the lowering of crack pH to acidic levels in notched specimens.
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Date Issued: 1976
PURL: http://purl.flvc.org/fcla/dt/13768
Subject Headings: Steel--Fatigue, Steel--Corrosion, Steel--Fracture, Notched bar testing
Format: Document (PDF)

Title: Fatigue crack growth rate of short cracks for high strength steels in sea water.
Creator: Kim, Kijoon., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Experiments have been performed which determined the fatigue crack growth rate (FCGR) of short cracks (a > 0.1mm) for five high strength steels (yield stress 370-570 MPa) in air and in natural seawater with and without cathodic protection. Attention was focused upon Regions I and Il of the classical FCGR-stress intensity range(Delta K) curve with particular consideration of the near-threshold behavior for short cracks. Single edge notch (SEN) three-point bend specimens and a direct current...
Show moreExperiments have been performed which determined the fatigue crack growth rate (FCGR) of short cracks (a > 0.1mm) for five high strength steels (yield stress 370-570 MPa) in air and in natural seawater with and without cathodic protection. Attention was focused upon Regions I and Il of the classical FCGR-stress intensity range(Delta K) curve with particular consideration of the near-threshold behavior for short cracks. Single edge notch (SEN) three-point bend specimens and a direct current potential drop (DCPD) crack monitoring system were employed, and test parameters simulated offshore structure conditions. The results indicated enhanced FCGR for short cracks compared to macrocracks by 3-20 times in air and 2-6 in seawater free-corroding(FC). Also, the Delta Kth for short cracks was apparently lower than for long ones in both environments. The transition from short to long crack behavior occurred at constant $\Delta$K in each environment (15.6 MPa m in air and 10.0 MPa m in seawater(FC)) irrespective of initial Delta K (Delta K(0)). The transition crack length ranged from 0.25 to 1.6 mm and was inversely proportional to $\Delta$K(0). Scanning electron microscope fractography showed that the mechanism of enhanced crack growth rate was associated with secondary crack (SC) formation in air and SC or inter-granular cracking (or both) in seawater (FC). The enhanced FCGR for short cracks was minimized by polarization to -950 mV(SCE). Through an elastic-plastic fracture mechanics analysis using the J-integral parameter it was found that the influence of plastic deformation at the crack tip was approximately independent of crack length (short versus long), and the linear-elastic fracture mechanics analysis gave a realistic representation for fatigue behavior.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/12313
Subject Headings: Steel--Fatigue--Environmental aspects, Underwater acoustics, Seawater--Acoustic properties
Format: Document (PDF)

Title: A PRELIMINARY STUDY OF WEAR OF AISI TYPE 304 STAINLESS STEEL AND MILD STEEL IN SEA WATER.
Creator: WENG, HARVEY H. L., Florida Atlantic University, Stevens, Karl K., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A fatigue machine was rebuilt to investigate the wear of mild steel and AISI Type 304 stainless steel while undergoing cyclic relative motions in air and sea water environments. Wear curves were obtained for both materials by measuring specimen weight loss as a function of the number of cycles of relative motion, and surface damage of the specimens was photographed. The results indicate that a sea water environment has a strong influence upon the wear characteristics of mild steel and 304...
Show moreA fatigue machine was rebuilt to investigate the wear of mild steel and AISI Type 304 stainless steel while undergoing cyclic relative motions in air and sea water environments. Wear curves were obtained for both materials by measuring specimen weight loss as a function of the number of cycles of relative motion, and surface damage of the specimens was photographed. The results indicate that a sea water environment has a strong influence upon the wear characteristics of mild steel and 304 stainless steel. For the mild steel, the corrosive effects of the sea water contributed to severe pitting and cracking of the wear surface and resulted in a significant increase in wear; after approximately 2.5 million cycles the amount of wear in sea water was approximately three times that in air. For the stainless steel, the sea water acted primarily as a lubricant and coolant, and served to reduce the amount of wear after 2.5 million cycles to about one-tenth of that in air.
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Date Issued: 1980
PURL: http://purl.flvc.org/fcla/dt/14031
Subject Headings: Steel--Fatigue--Environmental aspects, Steel, Stainless--Fatigue--Environmental aspects
Format: Document (PDF)

Title: Experimental and theoretical characterization of near-threshold fatigue crack growth for high strength steels in seawater.
Creator: Yang, Jingjun., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Near-threshold fatigue crack growth rate data were generated for six high strength steels at stress ratios of 0.5 and 0.8 under different environmental conditions, which included air, freely corroding in seawater, and cathodically polarized in seawater to -0.80v, -0.95v and -1.10v (vs SCE). The influence of stress ratio, loading frequency, magnitude of cathodic polarization and initial DeltaK on fatigue crack growth behavior for these high strength steels was experimentally characterized. The...
Show moreNear-threshold fatigue crack growth rate data were generated for six high strength steels at stress ratios of 0.5 and 0.8 under different environmental conditions, which included air, freely corroding in seawater, and cathodically polarized in seawater to -0.80v, -0.95v and -1.10v (vs SCE). The influence of stress ratio, loading frequency, magnitude of cathodic polarization and initial DeltaK on fatigue crack growth behavior for these high strength steels was experimentally characterized. The results disclosed general trends of fatigue crack growth under conditions relevant to offshore structure applications and circumscribed variables that are primarily influential with regard to service performance. The rate controlling processes and cracking mechanisms of near-threshold fatigue crack growth, particularly under cathodic polarization in seawater, were also studied in conjunction with crack mouth opening displacement measurements, fractographic observation and crack profile examination. The data and observations suggest that calcareous deposit induced closure was the rate-controlling factor for near-threshold fatigue crack growth under cathodic polarization in seawater although the cracking involved a brittle failure mechanism as a result of hydrogen embrittlement. With different FCGR determining procedures which included natural K-decreasing, enhanced K-decreasing, natural K-increasing and constant DeltaK, the FCGR under cathodic polarization in seawater was found to be time-dependent and, as such, was not a unique function of DeltaK but depended upon K-history or experimental procedures. These observations were consistent with results of a theoretical analysis which involved kinetics modeling of the interaction between fatigue crack growth and calcareous deposit thickening. The model also predicted the existence of an upper limit transition DeltaK, DeltaK Upp/T, between the Paris and threshold regions and it was found that the predicted DeltaK Upp/T was in agreement with the experimental one. The basis for applying this critical parameter (DeltaK Upp/T) to offshore structure designs was addressed in conjunction with experimental results.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/12410
Subject Headings: Seawater corrosion, Steel--Fatigue, Steel--Fracture, Corrosion and anti-corrosives
Format: Document (PDF)

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)

Steel--Fatigue (12)	+ -
Steel--Corrosion (3)	+ -
Corrosion and anti-corrosives (2)	+ -
Sea-water corrosion (2)	+ -
Steel--Fatigue--Environmental aspects (2)	+ -

Steel--Fracture (2)	+ -
Bridges--Fatigue (1)	+ -
Cathodic protection (1)	+ -
Fiber reinforced plastics (1)	+ -
Iron and steel bridges -- Corrosion (1)	+ -
Marine steel--Fatigue (1)	+ -
Notched bar testing (1)	+ -
Offshore structures (1)	+ -
Prestressed concrete construction (1)	+ -
Protective coatings -- Evaluation (1)	+ -
Reinforced concrete construction (1)	+ -
Seawater (1)	+ -
Seawater corrosion (1)	+ -
Seawater--Acoustic properties (1)	+ -
Steel -- Fatigue (1)	+ -
Steel, High strength (1)	+ -
Steel, Stainless--Fatigue--Environmental aspects (1)	+ -
Steel, Structural -- Corrosion (1)	+ -
Steel--Stress corrosion (1)	+ -
Underwater acoustics (1)	+ -

Florida Atlantic University (16)	+ -
Hartt, William H. (11)	+ -
College of Engineering and Computer Science (9)	+ -
Department of Ocean and Mechanical Engineering (9)	+ -
ADAMSON, JOHNNY DALE. (1)	+ -

Arockiasamy, Madasamy (1)	+ -
Badve, Ashwin P. (1)	+ -
CHU, ZIN-HON. (1)	+ -
Chen, Di (1)	+ -
Clark, A. M. (1)	+ -
Davidson, Keith Dewayne. (1)	+ -
FLUET, JOSEPH E., JR. (1)	+ -
Granata, Richard D. (1)	+ -
Haratt, William H. (1)	+ -
KRISHNAKUMAR, RENGAN. (1)	+ -
Kim, Kijoon. (1)	+ -
LEE, AI-KUO. (1)	+ -
MARTIN, PHILIP EDWARD (1)	+ -
Sablok, Anil Kumar. (1)	+ -
Sandepudi, Krishna Srinivasa. (1)	+ -
Stevens, Karl K. (1)	+ -
WEHLING, CHRISTOPHER MARK. (1)	+ -
WENG, HARVEY H. L. (1)	+ -
Yang, Jingjun. (1)	+ -

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