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Book Effect of Deformation Porperties on Bond slip Characteristics of Reinforcing Bars

Download or read book Effect of Deformation Porperties on Bond slip Characteristics of Reinforcing Bars written by Ghassan Khaled Jumah and published by . This book was released on 1992 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: The theory of reinforced concrete is based on stress transfer between steel and concrete. In order for the steel to develop its full yield force in tension, there should be some bond between that steel and the surrounding concrete. With the deformed bars, used in reinforced concrete construction since many decades, the problem of bond was the topic for many research programs dedicated for the investigation of the factors influencing that bond, Some of these factors are : bar size, cover thickness, spacing between embedded bars, and deformation properties of the bar itself. The objective of our research work was to investigate the effect of rib geometry or rib deformation properties on the bond-slip characteristics of deformed reinforcing bars. For that purpose, plain round Grade 60 bars 20.6 mm (0.811 in.) in diameter were machined to simulate #6 bars. Fifty six of these test bars were tested in eccentric pullout tests. The specimen was a concrete block with a 10-in. length and a 12in.xl2in. cross section. The bar was embedded along the 10-in. length and was loaded in tension until failure of the specimen in a V-notch splitting mode, where the test was halted. Such a short embedment length (10 in.^ for the test bar was chosen in order to avoid yielding of the bar and to minimize the difference in tensile stresses between the loaded-end and the free-end of the bar. The load and the free-end slip of the bar was monitored during the test. Seven series of pullout specimens were prepared and tested, and replicates were included to check the reliability of the test setup and the obtained results. In series ONE and FOUR, the main variable was the rib face angle where five rib face angles were investigated, 30, 45, 60, 75, and 90 degrees. The concrete compressive strength in series ONE was 3000 psi while in series SIX, it was 6000 psi. The main variable in series TWO and FIVE was the rib spacing. Five values of rib spacings were investigated, 0.3 in. (0.37 db), 0.35 in. (0.43 dO, 0.4 in. (0.49 db), 0.45 in. (0.55 db), and 0.5 in. (0.62 db). The rib height was investigated in series THREE and SIX with two different concrete compressive strengths, 3000 and 6000 psi respectively. Four values of rib heights were investigated; 0.04 in. (0.05 db), 0.06 in. (0.074 db), 0.08 in. (0.1 db), and 0.1 in. (0.124 db). Based on the test results of the first six series, the values for the variables in the seventh series were decided upon. In this last series, the rib spacing was kept constant and equal to 0.4 in. (0.49 db), and four combinations of rib face angles and rib heights were tested. The first two combinations had a rib face of 45 degrees and two different rib heights, 0.06 in. (0.074 db) and 0.08 in. (0.1 db), while the other two had a rib face angle 60 degrees with two different rib heights, 0.06 in. (0.074db) and 0.08 in. (0.1 db).

Book Effect of Deformation Properties on the Comparative Bond slip Behavior of Painted and Unpainted Reinforcing Bars

Download or read book Effect of Deformation Properties on the Comparative Bond slip Behavior of Painted and Unpainted Reinforcing Bars written by Bechara Patrick Alfred Sifri and published by . This book was released on 1993 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Characteristics of Reinforced Concrete Bond at High Strain Rates

Download or read book Characteristics of Reinforced Concrete Bond at High Strain Rates written by Eric Jacques and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the on-going intensity of research in the field of protective structural design, one topic that has been largely ignored in the literature is the effect of high strain rates on the bond between reinforcing steel and the surrounding concrete. Therefore, a comprehensive research program was undertaken to establish the effect of high strain rates on reinforced concrete bond. The experimental research consisted of the construction and testing of fourteen flexural beam-end bond specimens and twenty-five lap-spliced reinforced concrete beams. The physical and material properties of the specimens were selected based on a range of design parameters known to significantly influence bond strength. In order to establish a baseline for comparison, approximately half of the total number of specimens were subjected to static testing, while the remainder were subjected to dynamic loading generated using a shock tube. The strain rates generated using the shock tube were consistent with those obtained for mid- and far-field explosive detonation. Results of the beam-end and lap splice beam tests showed that the flexural behaviour of reinforced concrete was significantly stronger and stiffer when subjected to dynamic loading. Furthermore, the high strain rate bond strength was always greater than the corresponding low strain rate values, yielding an average dynamic increase factor (DIF) applied to ultimate bond strength of 1.28. Analysis of the low and high strain rate test results led to the development of empirical expressions describing the observed strain rate sensitivity of reinforced concrete bond for spliced and developed bars with and without transverse reinforcement. The predictive accuracy of the proposed DIF expressions was assessed against the experimental results and data from the literature. It was found that the dynamic bond strength of reinforced concrete can be predicted with reasonably good accuracy and that the proposed DIF expressions can be used for analysis and design of protective structures. An analytical method was also developed to predict the flexural load-deformation behaviour of reinforced concrete members containing tension lap splices. The analysis incorporated the effect of reinforcement slip through the use of pseudo-material stress-strain relationships, in addition to giving consideration to the effect of high strain rates on bond-slip characteristics and on the material properties of concrete and steel. A comparison of the analytical predictions with experimental data demonstrated that the proposed analysis technique can reasonably predict the flexural response of beams with tension lap splices. The results also demonstrated that the model is equally applicable for use at low- and high-strain rates, such as those generated during blast and impact.

Book Bond and Anchorage of Lap Splices of Reinforcing Bars with Different Deformation Properties

Download or read book Bond and Anchorage of Lap Splices of Reinforcing Bars with Different Deformation Properties written by Antoine Makhlouf and published by . This book was released on 1993 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beams were designed to include two reinforcing bars in tension, spliced at the center of the span. The splice length was selected so that the bars would fail in bond, splitting the concrete cover in the splice region, before reaching the yield point. The bars were plain round Grade 60 bars with the splice length machined to simulate #6 (20 mm) deformed bars with parallel deformation pattern and different deformation geometries. No transverse reinforcement was provided in the splice region. The beam was loaded in positive bending and designed with constant moment region at the center of the beam. At each load increment, the deflection at the center of the beam was recorded and flexural cracks were marked and their widths measured. The variables were the bar rib face angle, rib spacing, and rib height. The results of this study were combined with results of previous investigations by Prof. Hamad to come up with recommendations concerning optimum rib geometries of deformed bars with superior bond-slip characteristics.

Book Bond Stress slip Characteristics of FRP Rebars

Download or read book Bond Stress slip Characteristics of FRP Rebars written by L. Javier Malvar and published by . This book was released on 1994 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Improving Development Characteristics of Reinforcing Bars

Download or read book Improving Development Characteristics of Reinforcing Bars written by Civil Engineering Research Foundation and published by American Society of Civil Engineers. This book was released on 1994 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the development and implications of a new concrete reinforcing bar with significantly improved bond strength.

Book ACI Structural Journal

Download or read book ACI Structural Journal written by and published by . This book was released on 2009 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Bond of Reinforcemen Under Controlled Confinement

Download or read book Bond of Reinforcemen Under Controlled Confinement written by and published by . This book was released on 1991 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: Twelve specimens were tested to determine the local bond stress-slip characteristics of a No. 6 rebar embedded in a 3-inch diameter concrete cylinder. Radial confining stress around the concrete specimen and radial deformation were assumed to be fundamental variables, together with bond stress and slip, needed to properly describe the interface behavior. Configuration independent bond stress-slip, relationships for a short five-lug embedded length were obtained for various degrees of confining pressure. Maximum bond stresses could be increased almost threefold by increasing the confining stress from 500 to 4500 psi at the bar level. Two types of No. 6 bars with different deformations were investigated. In many reinforced concrete structures, the mode of failure is tensile cracking of the concrete. Where it is important to predict failure or severe damage, proper representation of bond is crucial. Principal gain from inclusion of actual bond-slip properties in the interface between steel rebar and concrete is a realistic prediction of cracking. The spacing, width, and extent of cracks in reinforced concrete are dependent on the assumed bond-slip characteristics. Critical Navy reinforced concrete structures, such as missile test cells and graving drydocks, are designed to withstand large deformations under severe blast and strong-motion earthquake loads. The development of design criteria for these structures requires evaluation of their response where severe deterioration of steel concrete interfaces takes place.

Book Case for Changing Reinforcing Bar Deformation Spacing Requirements

Download or read book Case for Changing Reinforcing Bar Deformation Spacing Requirements written by David Darwin and published by . This book was released on 2014 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The bond strength of four sets of reinforcing bars is evaluated, two each with No. 5 and No. 10 (No. 16 and No. 32) bars, which have, respectively, nominal diameters of 0.625 and 1.27 in. (15.9 and 32.3 mm). One bar of each size satisfies the criterion for maximum deformation spacing in ASTM reinforcing bar specifications, while the other has deformations that exceed the maximum spacing. All bars exceed the requirements for minimum deformation height. Research related to the effect of deformation properties on bond strength, including the research used to establish the requirements for deformations in ASTM reinforcing bar specifications, is also reviewed. The test results match earlier research and demonstrate that (1) bond strength is not governed by the specific value of deformation height or spacing, but by the combination of the two as represented by the relative rib area of the bars and (2) the bond strength of the bars with deformation spacings that exceed those in ASTM reinforcing bar specifications is similar to the bond strength of the bars that meet the specification. Based on this and prior research, it is recommended that ASTM reinforcing bar specifications be modified to allow for deformation spacing up to 90 % (currently a maximum of 70 %) of the bar diameter provided the ratio of deformation height to deformation spacing is greater than or equal to the minimum ratio for bar deformations meeting the current requirements in ASTM reinforcing bar specifications.

Book fib Model Code for Concrete Structures 2010

Download or read book fib Model Code for Concrete Structures 2010 written by fib - federation internationale du beton and published by John Wiley & Sons. This book was released on 2013-12-04 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International Federation for Structural Concrete (fib) is a pre-normative organization. 'Pre-normative' implies pioneering work in codification. This work has now been realized with the fib Model Code 2010. The objectives of the fib Model Code 2010 are to serve as a basis for future codes for concrete structures, and present new developments with regard to concrete structures, structural materials and new ideas in order to achieve optimum behaviour. The fib Model Code 2010 is now the most comprehensive code on concrete structures, including their complete life cycle: conceptual design, dimensioning, construction, conservation and dismantlement. It is expected to become an important document for both national and international code committees, practitioners and researchers. The fib Model Code 2010 was produced during the last ten years through an exceptional effort by Joost Walraven (Convener; Delft University of Technology, The Netherlands), Agnieszka Bigaj-van Vliet (Technical Secretary; TNO Built Environment and Geosciences, The Netherlands) as well as experts out of 44 countries from five continents.

Book Tests of Bond Between Concrete and Steel

Download or read book Tests of Bond Between Concrete and Steel written by Duff A. B. 1880 Abrams and published by Palala Press. This book was released on 2016-05-02 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

Book Scientific and Technical Aerospace Reports

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: