This paper presents the results of an experimental investigation on the anchorage of deformed steel bars embedded in bed joints of masonry. The effect of bar diameter, anchorage length and vertical load on the mortar joint is investigated. Although the horizontal bars in masonry are under favorable conditions, such as low strength of mortar, small cover values, lack of bond at places where the bars pass over large holes of the masonry unit, tests have proved that embedment lengths as low as 40 to 40 times the bar diameter seem to be sufficient for the bars to develop their yield strength.
{"title":"Pullout of Horizontal Reinforcement Embedded in Masonry","authors":"E. Vintzileous, N. Psilla","doi":"10.14359/5884","DOIUrl":"https://doi.org/10.14359/5884","url":null,"abstract":"This paper presents the results of an experimental investigation on the anchorage of deformed steel bars embedded in bed joints of masonry. The effect of bar diameter, anchorage length and vertical load on the mortar joint is investigated. Although the horizontal bars in masonry are under favorable conditions, such as low strength of mortar, small cover values, lack of bond at places where the bars pass over large holes of the masonry unit, tests have proved that embedment lengths as low as 40 to 40 times the bar diameter seem to be sufficient for the bars to develop their yield strength.","PeriodicalId":273104,"journal":{"name":"SP-180: Bond and Development of Reinforcement - A Tribute to Dr. Peter Gergely","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125920039","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}
Bond properties are usually described by empirical relations that are based on pull-out tests of bars with short embedment lengths cast in low to medium strength concrete. The limited validity of these formulations is recognized and their applicability in structural analysis is reconsidered. Results of two test series with various confining conditions and concrete strengths provide the basis for the derivation of a new bond model for ribbed bars. Pull-out bond failure in confined concrete and splitting bond failure in unconfined concrete have been studied. Steel yielding is found to have a considerable influence on bond strength. Significant differences in bond of NSC and HSC are confirmed. An analytical bond model for ribbed bars is developed. It is based on the confining capacity of the concrete surrounding the bar. This is evaluated with a thick-walled cylinder model, from which the relation between the radial displacement and the radial compressive stress at the steel-to-concrete interface is derived. The radial displacement at the interface is linked to the slip of the ribbed bar, distinguishing between the two modes of bond failure: pull-out and cover splitting. The model takes into account concrete toughness and bar contraction, also after yielding. Verification of the model against selected experimental results reflects the potential of the model to be used in a broad range of applications. In its present form the model is used for analysis of isolated bond problems using a one-dimensional finite difference approach, but its application is also considered to count for three-dimensional deformations if FE codes that treat the bar as a one-dimensional element.
{"title":"Bond of Ribbed Bars Modeled through Concrete Confinement","authors":"A. Bigaj, J. D. Uijl, J. Walraven","doi":"10.14359/5878","DOIUrl":"https://doi.org/10.14359/5878","url":null,"abstract":"Bond properties are usually described by empirical relations that are based on pull-out tests of bars with short embedment lengths cast in low to medium strength concrete. The limited validity of these formulations is recognized and their applicability in structural analysis is reconsidered. Results of two test series with various confining conditions and concrete strengths provide the basis for the derivation of a new bond model for ribbed bars. Pull-out bond failure in confined concrete and splitting bond failure in unconfined concrete have been studied. Steel yielding is found to have a considerable influence on bond strength. Significant differences in bond of NSC and HSC are confirmed. An analytical bond model for ribbed bars is developed. It is based on the confining capacity of the concrete surrounding the bar. This is evaluated with a thick-walled cylinder model, from which the relation between the radial displacement and the radial compressive stress at the steel-to-concrete interface is derived. The radial displacement at the interface is linked to the slip of the ribbed bar, distinguishing between the two modes of bond failure: pull-out and cover splitting. The model takes into account concrete toughness and bar contraction, also after yielding. Verification of the model against selected experimental results reflects the potential of the model to be used in a broad range of applications. In its present form the model is used for analysis of isolated bond problems using a one-dimensional finite difference approach, but its application is also considered to count for three-dimensional deformations if FE codes that treat the bar as a one-dimensional element.","PeriodicalId":273104,"journal":{"name":"SP-180: Bond and Development of Reinforcement - A Tribute to Dr. Peter Gergely","volume":"327 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115153589","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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