Epoxy-coated reinforcement and high-performance concrete are commonly used materials in exposed structures located in cold regions and marine environments of the United States. Their popularity is due to their resistance to corrosion in areas where chlorides are used as deicers in roads and bridges. This paper summarizes an experimental investigation regarding the difference in bond behavior of epoxy-coated and uncoated reinforcement in normal and high-strength concrete. The objectives were to investigate the effect of bar surface (epoxy, uncoated,) bar size (No. 6, No. 8, and No. 11), concrete strength (6, 10, 12, 14 ksi) and the addition of micro-silica to concrete. Ninety-four inverted half-beam specimens were tested. All of the specimens were designed to fail in bond by splitting of the concrete. The reinforcement in four of the specimens (two uncoated and two epoxy-coated reinforcement) was instrumented with internally embedded strain gages to measure the distribution of strain along the embedment length. The tests showed clear differences in the strain distribution at service level between coated and uncoated reinforcement. A comprehensive review of the effect of epoxy-coating on bond strength was conducted using the results of this study and 151 tests results from seven other research studies in the USA. The experimental results were compared to values of design bond strength calculated using ACI 318-89(1) and ACI 318-95 (2) equations.
{"title":"Bond of Epoxy-Coated Reinforcement in Normal and High-Strength Concrete","authors":"T. M. Grundhoffer, P. Mendis, C. French, R. Leon","doi":"10.14359/5881","DOIUrl":"https://doi.org/10.14359/5881","url":null,"abstract":"Epoxy-coated reinforcement and high-performance concrete are commonly used materials in exposed structures located in cold regions and marine environments of the United States. Their popularity is due to their resistance to corrosion in areas where chlorides are used as deicers in roads and bridges. This paper summarizes an experimental investigation regarding the difference in bond behavior of epoxy-coated and uncoated reinforcement in normal and high-strength concrete. The objectives were to investigate the effect of bar surface (epoxy, uncoated,) bar size (No. 6, No. 8, and No. 11), concrete strength (6, 10, 12, 14 ksi) and the addition of micro-silica to concrete. Ninety-four inverted half-beam specimens were tested. All of the specimens were designed to fail in bond by splitting of the concrete. The reinforcement in four of the specimens (two uncoated and two epoxy-coated reinforcement) was instrumented with internally embedded strain gages to measure the distribution of strain along the embedment length. The tests showed clear differences in the strain distribution at service level between coated and uncoated reinforcement. A comprehensive review of the effect of epoxy-coating on bond strength was conducted using the results of this study and 151 tests results from seven other research studies in the USA. The experimental results were compared to values of design bond strength calculated using ACI 318-89(1) and ACI 318-95 (2) equations.","PeriodicalId":273104,"journal":{"name":"SP-180: Bond and Development of Reinforcement - A Tribute to Dr. Peter Gergely","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129166387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An analytical model is presented to evaluate the local bond-slip relationship in RC lap splices considering the influence of splitting cracks, friction between the concrete and rib face, microscopic fracture of concrete in front of rib face, flexural deformation of the cover concrete and stirrups. The local bond-slip relationship is integrated along the splice length considering the strain in the concrete in the longitudinal direction. It is shown that the lack of friction at a rib face due to epoxy coating reduces the ductility of the local bond slip relationship without stirrups, resulting in lower splice strengths. The contribution of stirrups, and is the function of concrete strength rather than the yield strength of the stirrup.
{"title":"Fundamental Analysis of RC lap Splices","authors":"T. Ichinose, T. Hayashi, Wei Lin","doi":"10.14359/5888","DOIUrl":"https://doi.org/10.14359/5888","url":null,"abstract":"An analytical model is presented to evaluate the local bond-slip relationship in RC lap splices considering the influence of splitting cracks, friction between the concrete and rib face, microscopic fracture of concrete in front of rib face, flexural deformation of the cover concrete and stirrups. The local bond-slip relationship is integrated along the splice length considering the strain in the concrete in the longitudinal direction. It is shown that the lack of friction at a rib face due to epoxy coating reduces the ductility of the local bond slip relationship without stirrups, resulting in lower splice strengths. The contribution of stirrups, and is the function of concrete strength rather than the yield strength of the stirrup.","PeriodicalId":273104,"journal":{"name":"SP-180: Bond and Development of Reinforcement - A Tribute to Dr. Peter Gergely","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123243589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Compact Reinforced Composite (CRC) is a special concept for high performance concretes, where ductility is achieved through incorporation of a large content of short, stiff and strong steel fibers (6 vol.%). This ductility combined with high strength (150-400 MPa) and the ability of the small fibers to provide an effective reinforcement against even small cracks, makes it possible to obtain exceptional bond properties for deformed reinforcing bars. Results show that full anchorage is achieved with an embedment length of only 5-10 diameters for ribbed bars, which has led to applications in buildings, where CRC is used for in-situ cast joints between pre-cast decks - joints which can transfer full moments with a width of 100 mm. This type of joint, which was used for a university building, has been extensively tested for different loading situations and for behavior in a standard fire. As the fiber reinforced matrix provides a strong, ductile joint which responds well to dynamic loads it is expected to perform well under seismic loads.
{"title":"Bond Properties of High-Strength Fiber Reinforced Concrete","authors":"B. Aarup, B. Jensen","doi":"10.14359/5889","DOIUrl":"https://doi.org/10.14359/5889","url":null,"abstract":"Compact Reinforced Composite (CRC) is a special concept for high performance concretes, where ductility is achieved through incorporation of a large content of short, stiff and strong steel fibers (6 vol.%). This ductility combined with high strength (150-400 MPa) and the ability of the small fibers to provide an effective reinforcement against even small cracks, makes it possible to obtain exceptional bond properties for deformed reinforcing bars. Results show that full anchorage is achieved with an embedment length of only 5-10 diameters for ribbed bars, which has led to applications in buildings, where CRC is used for in-situ cast joints between pre-cast decks - joints which can transfer full moments with a width of 100 mm. This type of joint, which was used for a university building, has been extensively tested for different loading situations and for behavior in a standard fire. As the fiber reinforced matrix provides a strong, ductile joint which responds well to dynamic loads it is expected to perform well under seismic loads.","PeriodicalId":273104,"journal":{"name":"SP-180: Bond and Development of Reinforcement - A Tribute to Dr. Peter Gergely","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122491520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Safety concerns and a lack of test data on bond capacity of deformed reinforcing bars embedded in high-strength concrete are among the reasons for the ACI 318 building code imposing an arbitrary limitation of 10,000 psi (69 MPa) when calculating tension development and splice lengths. This limitation was first introduced in the 1989 revision of the ACI 318 building code. In an attempt to evaluate the impact of this limitation and develop provisions for its removal, an investigation was carried out at the University of Nebraska-Lincoln, partial result of which will be presented in this paper. Results of the investigation are used to discuss the differences that exist between normal and high strength concrete, develop hypotheses to explain these observed differences, and suggest alternatives for removal of the current concrete compressive limitations existing in the ACI 318 building code for calculating tension development and splice lengths. In this paper high strength concrete is defined as concrete with compressive strength exceeding 10,000 psi (60 MPa).
{"title":"Preventing Brittle Failure of Tension Splices in High-Strength Concrete","authors":"A. Azizinamini","doi":"10.14359/5880","DOIUrl":"https://doi.org/10.14359/5880","url":null,"abstract":"Safety concerns and a lack of test data on bond capacity of deformed reinforcing bars embedded in high-strength concrete are among the reasons for the ACI 318 building code imposing an arbitrary limitation of 10,000 psi (69 MPa) when calculating tension development and splice lengths. This limitation was first introduced in the 1989 revision of the ACI 318 building code. In an attempt to evaluate the impact of this limitation and develop provisions for its removal, an investigation was carried out at the University of Nebraska-Lincoln, partial result of which will be presented in this paper. Results of the investigation are used to discuss the differences that exist between normal and high strength concrete, develop hypotheses to explain these observed differences, and suggest alternatives for removal of the current concrete compressive limitations existing in the ACI 318 building code for calculating tension development and splice lengths. In this paper high strength concrete is defined as concrete with compressive strength exceeding 10,000 psi (60 MPa).","PeriodicalId":273104,"journal":{"name":"SP-180: Bond and Development of Reinforcement - A Tribute to Dr. Peter Gergely","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114548973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
When ribbed bars are anchored in linear structural members, the bond-slip behavior and the anchorage capacity is strongly influenced by splitting cracks. Many factors influence the formation of the splitting cracks, among others the anchorage length, the concrete cover, the bar spacing and arrangements, confinement from stirrups, flexural and shear cracks in the vicinity of the anchorage region, transverse pressure from support bearings, etc. These parameters often interact in a complex manner, and common design methods for anchorage regions are derived from empirical evaluations of test data and are often strongly simplified. The present study was carried out with the aim of studying the anchorage behavior of ribbed bars in structural members of high strength concrete and to check the applicability of some common design methods to these new materials. The influence of concrete type, normal or high-strength concrete, and various detailing of the node regions was examined. The tensile force in the active end of the anchorage zones was evaluated from steel strain measurements and was compared with predictions by means of strut and tie models. These models were found to consider the effect of inclined cracks in an appropriate and consistent way. The observed anchorage capacity was compared to some common design methods. It was found that the methods, to a considerable degree, were unable to reflect the real behavior. Further improvement and development of design and analytical tools is required.
{"title":"Pull-Out Bond Behavior of Ribbed Bars in Normal and High-Strength Concrete with Various Confinements","authors":"B. Engstrom, J. Magnússon, Zhiyong Huang","doi":"10.14359/5879","DOIUrl":"https://doi.org/10.14359/5879","url":null,"abstract":"When ribbed bars are anchored in linear structural members, the bond-slip behavior and the anchorage capacity is strongly influenced by splitting cracks. Many factors influence the formation of the splitting cracks, among others the anchorage length, the concrete cover, the bar spacing and arrangements, confinement from stirrups, flexural and shear cracks in the vicinity of the anchorage region, transverse pressure from support bearings, etc. These parameters often interact in a complex manner, and common design methods for anchorage regions are derived from empirical evaluations of test data and are often strongly simplified. The present study was carried out with the aim of studying the anchorage behavior of ribbed bars in structural members of high strength concrete and to check the applicability of some common design methods to these new materials. The influence of concrete type, normal or high-strength concrete, and various detailing of the node regions was examined. The tensile force in the active end of the anchorage zones was evaluated from steel strain measurements and was compared with predictions by means of strut and tie models. These models were found to consider the effect of inclined cracks in an appropriate and consistent way. The observed anchorage capacity was compared to some common design methods. It was found that the methods, to a considerable degree, were unable to reflect the real behavior. Further improvement and development of design and analytical tools is required.","PeriodicalId":273104,"journal":{"name":"SP-180: Bond and Development of Reinforcement - A Tribute to Dr. Peter Gergely","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125377537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Characteristic results of more than 100 cyclic pull-out tests are presented including various load histories (simulating realistic load spectra) like random loading or variable amplitude loading with increasing or decreasing tendencies in addition to the constant amplitude loading with different amplitudes. Slip measurements are compared to acoustic emission measurements. Repeated loading produces a progressive deterioration of bond caused by the propagation of micro-cracks and progress of micro-crushing in concrete. Deterioration of bond may be observed by measuring slip or acoustic emission events. It is quantitatively shown that the actual slip is significantly influenced by the load history: maximum and minimum levels of repeated load, type of amplitude (constant or variable), frequency, sequency of amplitudes and number of load cycles, respectively.
{"title":"Bond under Repeated Loading","authors":"G. Balázs","doi":"10.14359/5875","DOIUrl":"https://doi.org/10.14359/5875","url":null,"abstract":"Characteristic results of more than 100 cyclic pull-out tests are presented including various load histories (simulating realistic load spectra) like random loading or variable amplitude loading with increasing or decreasing tendencies in addition to the constant amplitude loading with different amplitudes. Slip measurements are compared to acoustic emission measurements. Repeated loading produces a progressive deterioration of bond caused by the propagation of micro-cracks and progress of micro-crushing in concrete. Deterioration of bond may be observed by measuring slip or acoustic emission events. It is quantitatively shown that the actual slip is significantly influenced by the load history: maximum and minimum levels of repeated load, type of amplitude (constant or variable), frequency, sequency of amplitudes and number of load cycles, respectively.","PeriodicalId":273104,"journal":{"name":"SP-180: Bond and Development of Reinforcement - A Tribute to Dr. Peter Gergely","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120959701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pullout tests were conducted on deeply embedded headed reinforcement to determine the effect of transverse reinforcement and bonded length on the side-blowout capacity and load-slip behavior of the anchorage. It was found that transverse ties or stirrups in the anchorage zone had little effect on the ultimate capacity. Increases in anchorage capacity were only observed when the head was positively anchored in contact behind a large crossing bar. Transverse reinforcement also had little effect on the load-slip behavior before failure. However, when large amounts to transverse reinforcement were placed near the head, the amount of load maintained after the blowout failure occurred was increased. Additional bonded length of a preformed reinforcing bar increased the anchorage capacity and reduced the head slip for a given load. The amount of increase in capacity can be predicted using current ACI provisions for development length. Design procedures taking into account the effects of transverse reinforcement and bonded length were developed.
{"title":"Effects of Transverse Reinforcement and Bonded length on the Side-Blowout Capacity of Headed Reinforcement","authors":"R. DeVries, J. Jirsa, Tarek R Bashandy","doi":"10.14359/5885","DOIUrl":"https://doi.org/10.14359/5885","url":null,"abstract":"Pullout tests were conducted on deeply embedded headed reinforcement to determine the effect of transverse reinforcement and bonded length on the side-blowout capacity and load-slip behavior of the anchorage. It was found that transverse ties or stirrups in the anchorage zone had little effect on the ultimate capacity. Increases in anchorage capacity were only observed when the head was positively anchored in contact behind a large crossing bar. Transverse reinforcement also had little effect on the load-slip behavior before failure. However, when large amounts to transverse reinforcement were placed near the head, the amount of load maintained after the blowout failure occurred was increased. Additional bonded length of a preformed reinforcing bar increased the anchorage capacity and reduced the head slip for a given load. The amount of increase in capacity can be predicted using current ACI provisions for development length. Design procedures taking into account the effects of transverse reinforcement and bonded length were developed.","PeriodicalId":273104,"journal":{"name":"SP-180: Bond and Development of Reinforcement - A Tribute to Dr. Peter Gergely","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127858365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fusion bonded epoxy coated reinforcement (FBECR) has been developed to help combat problems of corrosion in reinforced concrete structures. The surface texture of the coating is smoother than the normal mill scale surface of reinforcing bars and alters bond characteristics of the bar. Although FBECR has no been in use for more than 30 years and production standards have been established, rules for design using the material are not well developed. CEB Task Group 2/5 is currently reviewing data on bond and structural performance of elements reinforced with FBECR with the aim of deriving recommendations for design practice which will enable structures reinforced with FBECR to achieve equivalent performance to that f structures reinforced with millscale surface ribbed bars. This paper presents proposals for amendments to the CEB-FIP model Code 1990 for design of anchorages and splices of coated bars, and briefly reviews other aspects of structural performance influenced by the different bond characteristics of FBECR.
{"title":"Design Recommendations for Epoxy-Coated Reinforcement","authors":"J. Cairns, J. Jirsa, S. Mccabe","doi":"10.14359/5887","DOIUrl":"https://doi.org/10.14359/5887","url":null,"abstract":"Fusion bonded epoxy coated reinforcement (FBECR) has been developed to help combat problems of corrosion in reinforced concrete structures. The surface texture of the coating is smoother than the normal mill scale surface of reinforcing bars and alters bond characteristics of the bar. Although FBECR has no been in use for more than 30 years and production standards have been established, rules for design using the material are not well developed. CEB Task Group 2/5 is currently reviewing data on bond and structural performance of elements reinforced with FBECR with the aim of deriving recommendations for design practice which will enable structures reinforced with FBECR to achieve equivalent performance to that f structures reinforced with millscale surface ribbed bars. This paper presents proposals for amendments to the CEB-FIP model Code 1990 for design of anchorages and splices of coated bars, and briefly reviews other aspects of structural performance influenced by the different bond characteristics of FBECR.","PeriodicalId":273104,"journal":{"name":"SP-180: Bond and Development of Reinforcement - A Tribute to Dr. Peter Gergely","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128812612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper describes a theoretical and experimental analysis designed to characterize the initial branch of the bond-stress/slipping curves for normal-strength and high-strength concretes. The theoretical analysis is used to interpret the results of experimental trials on reinforced concrete ties prepared with class 50 and 100 MPa concrete mixtures and submitted to tensile forces without inducing any yield in the bar. The purpose of the investigation was to study any changes in bond behavior (over the limited range of slipping values considered) due to the better mechanical features of the 100 MPa concrete, and thus contribute to a better understanding of how high-strength reinforced concrete elements behave in a serviceability state.
{"title":"Tension Stiffening and Cracking Behavior in High-Strength Concrete","authors":"G. Creazza, R. DiMarco","doi":"10.14359/5874","DOIUrl":"https://doi.org/10.14359/5874","url":null,"abstract":"This paper describes a theoretical and experimental analysis designed to characterize the initial branch of the bond-stress/slipping curves for normal-strength and high-strength concretes. The theoretical analysis is used to interpret the results of experimental trials on reinforced concrete ties prepared with class 50 and 100 MPa concrete mixtures and submitted to tensile forces without inducing any yield in the bar. The purpose of the investigation was to study any changes in bond behavior (over the limited range of slipping values considered) due to the better mechanical features of the 100 MPa concrete, and thus contribute to a better understanding of how high-strength reinforced concrete elements behave in a serviceability state.","PeriodicalId":273104,"journal":{"name":"SP-180: Bond and Development of Reinforcement - A Tribute to Dr. Peter Gergely","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129033494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
From pull-out and push-in tests on specimens with short embedment length an empirical relation has been derived, which describes the local bond stress as a function of the local slip and steel stress change. With the help of this bond model the transfer length and the bi-linear relationship for the development length of a pretensioned strand (ACI Building Code 1989, CEB-FIP Model Code 1990) is simulated. It is also used to indicate the influence of strand yielding on the development length. For the estimation of the concrete cover and strand spacing required to prevent the occurrence of visible bond splitting cracks the response of the concrete to the radial displacement of the strand-to-concrete interface is analyzed by means of a so-called thick-walled-cylinder model. The radial interface displacement consists of transverse deformation of the strand coupled with steel stress change (Poisson effect) and wedging action caused by the shape of the strand (lack-of-fit effect) and surface roughness. Besides the section geometry, this model takes into account the softening behaviour of concrete loaded in tension, It is used to explain the influence of various parameters such as concrete cover, strand spacing, strand diameter and concrete strength on the bond properties of strand.
{"title":"Bond Modelling of Prestressing Strand","authors":"den Uijl","doi":"10.14359/5876","DOIUrl":"https://doi.org/10.14359/5876","url":null,"abstract":"From pull-out and push-in tests on specimens with short embedment length an empirical relation has been derived, which describes the local bond stress as a function of the local slip and steel stress change. With the help of this bond model the transfer length and the bi-linear relationship for the development length of a pretensioned strand (ACI Building Code 1989, CEB-FIP Model Code 1990) is simulated. It is also used to indicate the influence of strand yielding on the development length. For the estimation of the concrete cover and strand spacing required to prevent the occurrence of visible bond splitting cracks the response of the concrete to the radial displacement of the strand-to-concrete interface is analyzed by means of a so-called thick-walled-cylinder model. The radial interface displacement consists of transverse deformation of the strand coupled with steel stress change (Poisson effect) and wedging action caused by the shape of the strand (lack-of-fit effect) and surface roughness. Besides the section geometry, this model takes into account the softening behaviour of concrete loaded in tension, It is used to explain the influence of various parameters such as concrete cover, strand spacing, strand diameter and concrete strength on the bond properties of strand.","PeriodicalId":273104,"journal":{"name":"SP-180: Bond and Development of Reinforcement - A Tribute to Dr. Peter Gergely","volume":"314 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116177998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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