Download or read book Experimental and Analytical Evaluation of the Behavior of Continuous Concrete Beams Prestressed with External Tendons written by Jack Adel al-Hajj and published by . This book was released on 2001 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: After a short introduction of the electron spin resonance theory, the theory of the g-factor, and a discussion of the asymmetry of the spectra, a survey of the literature on the phenoxazines is presented. Two specific ways of preparation of free radicals have been described in detail. The experiment shows that two free radicals are obtained from resazurin. The first one is proved to be the free radical of resazurin, while the second one is shown to belong to resorufin, which is obtained from resazurin by breaking the N-0 bond. The spectra of phenoxazine, resorufin, and resazurin are analyzed and the hyperfine structure constants are compared with the calculation of spin densities based on Hfickel Molecular Orbital theory. In the case of resorufin and resazurin, better agreement is obtained than in the case of phenoxazine* The g-values of the above molecules have been measured accurately. The asymmetry of the obtained spectra has been interpreted and is found to be in accordance with the relaxation theory presented in the literature.
Download or read book Experimental and Analytical Evaluation of the Behavior of Concrete T Beams with External Prestressing written by Nada Emile Khairallah and published by . This book was released on 1997 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: The behavior and flexural resistance of reinforced concrete T beams strengthened using external prestressing were experimentally and analytically investigated. The behavior at both serviceability and limit states were evaluated. A total of twelve beams was tested. The main test variables included ratio of the ordinary reinforcing steel, magnitude of the external prestressing force (or area of external prestressing steel), and profile of the external prestressing tendons. The results indicated clearly that external prestressing is a very powerful technique for strengthening concrete flexural members. The use of external prestressing delayed the formation of flexural cracks, reduced the service load deflections, enhanced the shear performance, and increased the ultimate flexural strength up to 14percent in comparison with conventional reinforced concrete specimens. However, the corresponding improvement in the strength and behavior is accompanied by reduction in the ductility of flexural failure. Everything else being constant, external tendons with deviated profile were more effective in increasing the flexural strength than tendons with straight profile. The experimental results were reproduced analytically using a nonlinear analysis method. The nonlinear analysis method requires constitutive analytical relationships of the stress-strain curves of the constituent materials, namely, concrete, prestressing steel, and ordinary steel, and iteration procedure to satisfy deformation compatibility and force equilibrium at every stage during the load-deformation response of the member. The analytical results based on nonlinear analysis were in very good agreement with the experimental results. Furthermore, comparison was made between the experimental results of the stress in the external prestressing steel and available design equations. Based on this comparison, it was found that the stress in the external prestressing steel and the nominal flexural resistance of externally prestressed members can be predicted with reasonable accuracy using the ACI Building Code approach for beams prestressed with internal unbonded tendons.
Download or read book Experimental and Analytical Study of the Behavior of Concrete Beams Prestressed with Unbonded Tendons written by Muhamed H. Harajli and published by . This book was released on 1990 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flexural Behavior of Concrete Beams Prestressed with Bonded and Unbonded Tendons written by Adi Abu-Obeidah and published by . This book was released on 2017 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of unbonded tendons in prestressed concrete beams has been widely utilized in bridges, parking structures, and residential buildings for strengthening, rehabilitation or repair of such members. With the growth of live load and the increase of damaged concrete members, there is a need to develop and utilize new techniques for more efficient and improved designs in prestressed concrete members. This research presents an experimental and analytical investigation for the use of combination of bonded and unbonded tendons in the same concrete members. With the availability of high strength concrete, as well as the development of new prestressing technologies, the process can be easily performed at the site for repair or capacity upgrading resulting in longer spans for the same section depth or shallower sections. There is a knowledge gap on the behavior of concrete beams prestressed with hybrid tendons and a need to fully understand their overall behavior under full service loads. The hybrid technique introduces unbonded CFRP tendons, which is resistant to corrosion. In addition, CFRP tendons exhibit linear stress-strain relationship resulting in more accurate predictions for the tendon stress at ultimate. This hybrid system presents a challenge in developing an analytical model that could predict their behavior since the unbonded tendon is not bonded with the concrete. This investigation included the testing of 15 High Strength Concrete (HSC) beams prestressed with hybrid tendons. Results from the experimental study included number of cracks, load-deflection behavior, and strains in prestressing strand, reinforcing steel, and concrete. This study emphasizes the prediction of the ultimate stress of the unbonded tendon (fps) in unbonded or hybrid system for computing the ultimate moment resistance. Finite element modeling and analysis of various beams is performed. Based on a comparison of equations available in the literature as well as code provisions with the experimental results, a simplified prediction equation for predicting the stress in the unbonded tendons at ultimate is recommended.
Download or read book ACI Materials Journal written by and published by . This book was released on 2008 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Durability and Behavior of Prestressed Concrete Beams written by E. C. Roshore and published by . This book was released on 1971 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An experimental and analytical study of prestressed concrete beams made continuous by local post stressing with particular reference to ultimate moment distribution written by Hosagrahar Chandrasekharaiya Visvesvaraya and published by . This book was released on 1956 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ON THE FLEXURAL BEHAVIOR OF CONCRETE BEAMS PRESTRESSED WITH UNBONDED INTERNAL AND EXTERNAL TENDONS UNBONDED TENDONS BEAMS written by FADI MAAZ ALKHAIRI and published by . This book was released on 1991 with total page 916 pages. Available in PDF, EPUB and Kindle. Book excerpt: from 15 different investigations. Excellent correlation was obtained between predicted vs. experimental results. The present investigation suggests that shear deformations may have some effect on the stress increase in unbonded tendons for beams having low span-to-depth ratios, while eccentricity variations in external tendons significantly affect the overall behavior for beams having high span-to-depth ratios.
Download or read book Full Range Behaviour of Concrete Beams Partially Prestressed with Unbonded Tendons written by Karmen Tso and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Full-range Behaviour of Concrete Beams Partially Prestressed With Unbonded Tendons" by Karmen, Tso, 曹嘉雯, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: ABSTRACT OF THESIS ENTITLED Full-range Behaviour of Concrete Beams Partially Prestressed with Unbonded Tendons submitted by TSO Karmen for the degree of Master of Philosophy at The University of Hong Kong in February 2007 External prestressing can be applied to both new construction and retrofitting of existing reinforced and prestressed concrete structures. The behaviour of prestressed concrete structures with unbonded tendons differs significantly from that of those with bonded tendons after the working stage. To assess the safety of such structures, it is necessary to carry out full-range analysis, with particular attention to the post-peak behaviour. This thesis presents the results of an experimental study of externally prestressed concrete beams with either conventional or non-conventional tendons, which were tested to failure. The specimens tested all had T-sections prestressed by two external tendons with one on each side. Two types of tendon were used, namely 7-wire steel strands of 10.5 mm diameter and aramid fibre reinforced polymer (AFRP) tendons of 13.5 mm diameter. Unlike the steel tendons, the fibre reinforced polymer (FRP) tendons are not prone to corrosion. However, the prestressing operations for FRP tendons had to be modified to suit. In the experiments, different factors were taken into consideration. They included the level of prestressing force, concrete strength, area of non-prestressed steel reinforcement and partial prestressing ratio. - 1 - The full-range behaviour of partially prestressed concrete with either external unbonded steel or fibre reinforced polymer (FRP) tendons was significantly affected by second-order effects, as demonstrated in the strain profiles of top and bottom non- prestressed reinforcement and the variations of curvature and neutral axis depth. During the investigation of tendon force, the friction loss at deviator was found to be much greater than the friction loss estimated from the coefficients of friction given by the manufacturers. The equivalent coefficients of friction of steel and AFRP tendon were studied. Lastly, by using various ductility and deformability indices, the ductility or deformability of partially prestressed concrete with external unbonded tendons were investigated. The most suitable ductility or deformability index is proposed. (TSO Karmen) (302 words) - 2 - DOI: 10.5353/th_b3822557 Subjects: Tendons (Prestressed concrete) - Testing Prestressed concrete beams - Testing
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1992 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plastic Behaviour of Continuous Prestressed Concrete Beams written by Syed Bashir Ali and published by . This book was released on 1961 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Steel Structures ICASS 96 written by S.L. Chan and published by Elsevier. This book was released on 1996-12-06 with total page 655 pages. Available in PDF, EPUB and Kindle. Book excerpt: These two volumes of proceedings contain 11 invited keynote papers and 172 contributed papers presented at the International Conference on Advances in Steel Structures held on 11-14 December 1996 in Hong Kong. The papers cover a wide spectrum of topics and have been contributed from over 20 countries around the world. The conference, the first ever of its kind in Hong Kong, provided a forum for discussion and dissemination by researchers and designers of recent advances in the analysis, behaviour, design and construction of steel structures.The papers in the proceedings report the current state-of-the-art and point to the future directions of structural steel research. Volume I contains 93 papers on the analysis, behaviour, design and construction of framed structures and bridges, with 90 papers in Volume II dealing with plates, shells, analysis, optimization and computer applications, dynamics and seismic design, fatigue, and soil-structure interaction.
Download or read book Concrete Solutions 2014 written by Michael Grantham and published by CRC Press. This book was released on 2014-08-18 with total page 834 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Concrete Solutions series of International Conferences on Concrete Repair began in 2003 with a conference held in St. Malo, France in association with INSA Rennes. Subsequent conferences have seen us partnering with the University of Padua in 2009 and with TU Dresden in 2011. This conference is being held for the first time in the UK, in associ
Download or read book Proceedings of the 2023 4th International Conference on Management Science and Engineering Management ICMSEM 2023 written by Suhaiza Hanim Binti Dato Mohamad Zailani and published by Springer Nature. This book was released on 2023-11-10 with total page 1820 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an open access book.Management science aims to study the dynamic study of human use of limited resources in management activities to achieve organizational goals: complex and innovative social behavior and its laws. And engineering management refers to the management of important and complex new products, equipment and devices in the process of development, manufacturing and production, and also includes the study and management of technological innovation, technological transformation, transformation, transformation, layout and strategy of industrial engineering technology development. The development or breakthrough of management theory is accompanied by the development and progress of science and technology, and the level of science and technology and the level of management theory in each historical period are mutually adaptive, and it can be said that the progress of science and technology plays an important role in promoting the development of management. At the same time, the rapid development and progress of science and technology give a strong injection to the development of engineering, and provide the possibility for engineering construction can use new technology, new equipment, new technology and new materials. Modern management is an important development direction of management science nowadays. And the use of modern management in engineering has an important role in saving social costs, ensuring project quality, and improving safety awareness and behavior. ICMSEM 2023 will focus on modern management, discuss about the benefits that modernization brings to engineering. ICMSEM 2023 aims to: Develop and advance management science through the study and application of certain issues. Open up new perspectives in the sharing of speakers and inspire the audience to new ways of managing in engineering. Create a forum for sharing, research and exchange at the international level, so that the participants can be informed of the latest research directions, results and contents of management science, which will inspire them to new ideas for research and practice.
Download or read book Advances in Steel Structures written by S.L. Chan and published by Elsevier. This book was released on 1996-12-06 with total page 655 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volumes and section headings: Volume I. Keynote Papers. Beams and Columns. Frames and Trusses. Space Structures. Connections. Composite Construction. Bridges. Design and Construction. Volume II. Keynote Papers. Plates. Shells. Analysis. Optimization and Computer Applications. Dynamics and Seismic Design. Fatigue. Soil Structure Interaction.
Download or read book Proceedings of the Tenth U S Japan Conference on Composite Materials written by Fu-Kuo Chang and published by DEStech Publications, Inc. This book was released on 2002 with total page 1136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presentations by advanced materials specialists from around the world. Of special interest in this volume are the presentations on application areas such as automotive and civil engineering, nanomaterials, ceramic/metal composites, smart materials, and composite structures.
Download or read book Simplified Method for Failure Analysis Oc Concrete Beams Prestressed with External Tendons written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
