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Book Shear Strengthening of RC Deep Beams with Large Openings Using Carbon Fiber Reinforced Polymers  CFRP

Download or read book Shear Strengthening of RC Deep Beams with Large Openings Using Carbon Fiber Reinforced Polymers CFRP written by Foo Sheng Tong and published by . This book was released on 2015 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research deals with the experimental study of the behaviour of reinforced concrete deep beams with or without large rectangular openings as well as openings strengthened using externally bonded Carbon Fiber Reinforced Polymer (CFRP) composites in shear. The structural behaviour, including the load deflection, cracking patterns, failure mode, and effectiveness of the CFRP wraps were investigated. A total of four (4) specimens of beams with compressive strength of 35 MPa were tested to induce shear failure under 4 points loading test, which included one solid deep beam acted as a control beam (CB), one of which was tested without strengthening (US-BRO), and the remaining beams were strengthened with CFRP wraps in varying configurations around the opening (S-BRO-1, S-BRO-2). The beam had a cross section of 120 mm in width and 600 mm in depth as well as a length of 2400 mm. All the test specimens had a same geometry, main reinforcement arrangements and openings location. All the preparatory works of specimen materials were conducted in Laboratory FKASA. The examined parameter was the effect of configurations of the CFRP wraps used for the shear strengthening. The inclusion of un-strengthened large rectangular openings in the shear zone of a reinforced concrete deep beam leads to a reduction of ultimate beam strength by approximately 70%. The application of CFRP wraps with the presented strengthening configurations restricted the propagation of the diagonal crack and effectively increases ultimate load-carrying capacity as well as the ductility of the beam. The strength re-gains by U-shaped strengthening configuration around the openings was approximately 36% as compared to the beam with un-strengthened openings. However, the deep beam with U-shaped CFRP with horizontal fiber strengthened at the top and bottom chords of the openings were not capable to restore the control beam's original structural strength remarkably. The beam only managed to re-gain about 41% of the control beam's capacity.

Book Strengthening of Reinforced Concrete Deep Beams Having Large Square Openings in Shear Zone with Carbon Fiber Reinforced Polymer  CFRP  Wrap

Download or read book Strengthening of Reinforced Concrete Deep Beams Having Large Square Openings in Shear Zone with Carbon Fiber Reinforced Polymer CFRP Wrap written by Kin Mun Ng and published by . This book was released on 2015 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: Typically, the reinforced concrete (RC) deep beam with large openings are facing some severe problems such as the interruption of natural load transfer by concrete struts acting in compression which can cause an intensive reduction in strength; and the clearly visible cracks in serviceability conditions. The CFRP has become an alternative solution to this issue and being extensively used as an external reinforcement to resolve the strength requirements in structural systems due to extremely strong yet light weight, outstanding fatigue properties, excellent corrosion resistance and easy yet efficient application on concrete. This experimental study is focuses on the investigation of the effect of CFRP wrap in strengthening RC deep beams with large square openings located in shear zone. Three approaches are under consideration; the first is the determination of natural load transfer in normal deep beam without opening, the second is the large square openings in deep beam without CFRP strengthening, and the third is the large square openings in deep beam with CFRP attached around the openings. A total of four RC deep beams which included a solid RC control beam, a deep beam with two large square openings, and two beams with two large square openings strengthened by using CFRP strips in different strengthening configurations, were tested to failure under four point loading to determine the relative structural behaviour such as ultimate load, failure mode, crack patterns, and load deflection behaviour. All RC deep beams were designed in a dimension of 120 x 600 mm and 2400 mm in length. The width and height of large square openings were in a dimension of 270 x 270 mm and located 300 mm from the edge of the deep beam. The loading point and support were located at 800 mm and 300 mm from the edge of the deep beam, respectively. RC deep beam with large square openings, US-BSO was significantly reduced the beam capacity by 61.76 % as compared to solid control beam, CB. However, the RC deep beam with large square openings strengthened by CFRP strips wrapped in U-shaped, SU-BSO has increases the beam capacity by 62.77 % compared to US-BSO. From the results obtained, it was found that the most effective CFRP strengthening method for RC deep beam with large square openings was U-shaped, which recovered the beam capacity up to 62.24 % as compared to solid control beam.

Book Reinforced Concrete Deep Beams

Download or read book Reinforced Concrete Deep Beams written by F K Kong and published by CRC Press. This book was released on 1991-05-01 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: The contents of this book have been chosen with the following main aims: to review the present coverage of the major design codes and the CIRIA guide, and to explain the fundamental behaviour of deep beams; to provide information on design topics which are inadequately covered by the current codes and design manuals; and to give authoritative revie

Book Experimental Study on the Behaviour of Reinforced Concrete Deep Beams with Large Circular Openings Strengthened Using CFRP

Download or read book Experimental Study on the Behaviour of Reinforced Concrete Deep Beams with Large Circular Openings Strengthened Using CFRP written by Wen Khai Chong and published by . This book was released on 2015 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: This experimental research was conducted to study the behaviour of unstrengthen RC deep beams with openings and strengthened using Carbon Fiber Reinforced Polymer (CFRP). Strengthening configuration of CFRP-wrap used in this study were U-wrap and surface-wrap which applied with one layer of CFRP and in vertical alignment (90o). Four RC deep beams which included a solid control beam, a beam with two large circular openings, beams with two large circular openings strengthened using U-wrap and surface-wrap were tested to failure under four-point loading. All the beam specimens were in a dimension of 120 x 600 mm and 2400 mm in length. The support and loading point were located at 300 mm and 800 mm from the edge of the RC deep beams, respectively. Circular openings was designed with a standard of 0.45h which considered as large circular openings in a diameter of 270 mm that located 435 mm from the edge of the RC deep beams. Shear span-to-depth ratio (a/h) in this study was 0.83 in which the distance between the loading point and the support was 500 mm in order for the beam specimens to fail in shear region. RC deep beam with large circular openings, NS-BCO greatly reduced the beam strength, approximately 51.20 % as compared to the control beam. On the other hand, RC deep beam with circular openings strengthened using U-wrap, UW-BCO increases the beam strength up to almost 85.0 % as compared to NS-BCO. Hence, the most effective strengthening method was U-wrap, UW-BCO which re-gained the beam strength up to 90.28 % as compared to control beam.

Book Concrete Beams with Openings

Download or read book Concrete Beams with Openings written by M. A. Mansur and published by CRC Press. This book was released on 1999-01-29 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book compiles state-of-the-art information on the behavior, analysis, and design of concrete beams containing transverse openings. Discussions include the need, effects, and classification of openings as well as the general requirements for fulfilling design pure bending, combined bending, and shear - illustrated with numerical examples torsion alone or in combination with bending and shear large rectangular openings as well as opening size and location on beam behavior methods for analyzing ultimate strength and serviceability requirements effects of torsion in beams large openings in continuous beams and their effects on possible redistribution of internal forces as well as guidelines and procedures for the design of such beams effect of prestressing on the serviceability and strength of beams with web openings design against cracking at openings and ultimate loads Concrete Beams with Openings serves as an invaluable source of information for designers and practicing engineers, especially useful since little or no provision or guidelines are currently available in most building codes.

Book Shear Strengthening of Reinforced Concrete Beams Using Fiber Reinforced Polymer Wraps

Download or read book Shear Strengthening of Reinforced Concrete Beams Using Fiber Reinforced Polymer Wraps written by and published by DIANE Publishing. This book was released on with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Finite Element Analysis of RC Deep Beams with Openings Strengthened by Carbon Fiber Reinforced Polymer  CFRP

Download or read book Finite Element Analysis of RC Deep Beams with Openings Strengthened by Carbon Fiber Reinforced Polymer CFRP written by Chun Mun Seow and published by . This book was released on 2015 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Shear Strengthening of Reinforced Concrete Beams with Bi directional Carbon Fiber Reinforced Polymer  CFRP  Strips and CFRP Anchors

Download or read book Shear Strengthening of Reinforced Concrete Beams with Bi directional Carbon Fiber Reinforced Polymer CFRP Strips and CFRP Anchors written by Nawaf Khaled Alotaibi and published by . This book was released on 2014 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of externally bounded Carbon Fiber Reinforced Polymer (CFRP) for strengthening existing RC structures has shown promising results. Although CFRP materials have high tensile strength, the ability to utilize that strength is limited by debonding of the CFRP laminates from the concrete surface. In order to prevent or delay debonding, CFRP anchors were used to provide an alternative means of transferring forces from CFRP strips to the concrete. Previous tests on prestressed I-girders strengthened with uni-directional and bi-directional CFRP strips showed that bi-directional CFRP application resulted in significant shear strength gain in comparison to a uni-directional application. The objective of this thesis is to evaluate the behavior of reinforced concrete beams strengthened in shear with bi-directional CFRP strips and CFRP anchors so that the findings from the previous work can be understood and implemented. Four 24 in. deep T-beams were fabricated at the Phil M. Ferguson Structural Engineering Laboratory at The University of Texas at Austin. Eight tests were conducted on these specimens to examine the effect of the bi-directional layout of CFRP on the shear strength. Specimens with 14-in. web width were selected as a part of the experimental program to allow for direct comparison with test results from the previous project. Additional beams with a web width of 8 in. were included to evaluate thinner webs similar to those in the I-girders. Test results indicate a significant increase in shear strength due to the bi-directional application of CFRP strips with CFRP anchors installed on beams with a shear span-to-depth ratio (a/d) of 3. Substantial shear strength gain up to 62% was achieved in beams with 14-in. webs. and up to 43% for beams with 8-in. webs. However, negligible shear strength gain was observed in beams with a/d of 1.5 (deep beams). Experimental test results demonstrate an interaction between the contribution of concrete, transverse steel and CFRP to the shear resistance of a reinforced concrete beam. The findings of this research contribute to a better understanding of the shear behavior of reinforced concrete members strengthened with externally bonded CFRP applied bi-directionally. Experimental results from this research project provide data needed in the field of CFRP shear strengthening since limited data are available on large-scale tests.

Book Strengthening of Concrete Deep Beams with Extreme Discontinuities Using Near surface Mounted Composites

Download or read book Strengthening of Concrete Deep Beams with Extreme Discontinuities Using Near surface Mounted Composites written by Moustafa Seifeddin Mansour and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Installation of a web opening that fully interrupts the natural load path in concrete deep beams produces regions of extreme discontinuities and reduces the shear strength. This research examined the effectiveness of using near-surface-mounted carbon fiber-reinforced polymer (NSM-CFRP) reinforcement to restore the shear strength of deep beams with extreme discontinuities. The strut-and-tie model (STM) procedures were utilized to develop three different strengthening solutions around the discontinuity regions. A total of eight deep beam specimens (150 x 500 x2700 mm) with a shear span-to-depth ratio of a/h = 0.8 were constructed and tested. One beam was solid. Seven beams had a square opening in the middle of the shear span with an opening height ratio of ho/h = 0.2. Six beams were strengthened with NSM-CFRP around the discontinuity regions. Three-dimensional finite element (FE) models were developed to simulate the nonlinear behavior of the tested specimens. Experimental results were compared to predictions of the FE models and the STM design solutions to examine their accuracy and validity. Installation of the web opening resulted in a 40% reduction in the shear strength. The NSM-CFRP strengthening solutions fully restored the original shear strength, except in two cases where only 93% and 94% of the capacity were restored. The laboratory test results were used to determine the optimal NSM-CFRP strengthening solution. The STM based on provisions of the American Concrete Institute provided realistic and consistent predictions for the nominal strength of the tested specimens with an average predicted-to-measured strength ratio of 1.01±0.09. In contrast, the STM predictions based on provisions of the Canadian Standards Association tended to be conservative with an average predicted-to-measured strength ratio of 0.71±0.29. Predictions of the FE models were sensitive to the mesh size and the concrete constitutive law adopted in the analysis. The inclusion of a bond-slip model between the CFRP and concrete resulted in up to a 5% reduction in the predicted strength. The use of a small mesh size of 15 mm and a “user” concrete constitutive law rather than a “default” law yielded more accurate predictions that were insignificantly different from those obtained from the tests

Book Numerical Analysis on the Behaviour of CFRP Shear strengthened RC Deep Beams with Large Square and Circular Openings

Download or read book Numerical Analysis on the Behaviour of CFRP Shear strengthened RC Deep Beams with Large Square and Circular Openings written by Chee Wei Shim and published by . This book was released on 2015 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study presents a finite element analysis to investigate the behaviour of reinforced concrete deep beams with square and circular openings. Deep beams are always constructed at the lower floors as transfer beams to transfer the loads from the entire building to the foundations. Reinforced concrete (RC) acts as one of the most essential building materials and it is widely used in the construction due to its low pricing, efficiency and strength of the reinforced concretes as well as its stiffness. Openings are inevitable for the architectural and mechanical purpose to accommodate the conduits. However, presence of openings in the deep beams will significantly reduce the load capacity of the deep beams, as well as excessive cracking and deflection. Strengthening by Carbon Fibre Reinforced Polymer helps in regain the load bearing capacity of the deep beams. Researches were focus on the experimental work and hence this study conducted in terms of the numerical aspects and finite element analysis. ANSYS CivilFEM 12.0, a finite element modelling and analysis software, was used to analysis the deep beams. Three - dimensional modelling of RC deep beams was adopted in this study. A total of 14 beams including one control beam were modelled as simply supported beam with openings where the locations of the openings were at the support which was 300 mm from the edge of the beams. Two incremental loads were applied at the 800 mm from the edge of the beams. The beams was symmetrical in shape. The beams had the cross sections of 120 mm x 600 mm and 2400 mm in length with square and circular openings. The objectives of this study were to determine the most effective strengthening method by using CFRP in terms of load-deflection behaviours, crack patterns, stress and strain contours. This study was validated by experimental results. Various strengthening methods were used to identify the most effective method of strengthening which included orientation of CFRP in vertical alignment (90o), horizontal alignment (0o), whole piece, cut strips, surface strengthening and U-wrap strengthening. Deep beams with openings failed due to shear cracks because of the sharp edges of the openings. From the finding, the square opening and circular opening experienced a reduction of 62.0% and 51.3% in beam capacity, respectively. From the various strengthening configurations of CFRP, configuration with vertical alignment, whole piece and U-wrap strengthening method was the most effective method. CFRP restored the load bearing capacity with most effective method by 63.0% and 85.0% for deep beams with square and circular openings respectively. A comparison between the numerical and experiments results showed that a comparable agreement on the load deflection behaviours and strong agreement on the crack patterns.

Book Shear Strengthening of Reinforced Concrete Beams with Carbon Fiber Reinforced Polymer  CFRP  and Improved Anchor Details

Download or read book Shear Strengthening of Reinforced Concrete Beams with Carbon Fiber Reinforced Polymer CFRP and Improved Anchor Details written by Kevin Timothy Quinn and published by . This book was released on 2009 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fifteen tests were conducted to evaluate the shear performance of beams with carbon fiber reinforced polymer (CFRP) laminates and CFRP anchors. The specimens consisted of 24-in. deep T-beams. The specimens were strengthened in shear with CFRP laminates that were anchored using several different CFRP end anchorage details. Load was applied to the reinforced concrete members at three different shear span-to-depth ratios. Observations of the behavior and data from the tests were used to evaluate the performance of the CFRP laminates and CFRP anchors. Overall, a 30-40% increase in shear strength was observed when anchored CFRP laminates were installed on members loaded at a shear span-to-depth ratio greater than two. The CFRP strengthening system performed well when properly detailed CFRP anchors were installed. Design recommendations regarding the installation of the CFRP anchors were developed. The CFRP anchorage detail developed in this study provided additional CFRP material in critical locations to reinforce the anchor and prevent premature failures from occurring due to anchor rupture. Theoretical calculations predicting the shear strength of the retrofitted concrete members were carried out and compared to the measured strengths of the members. Based on this analysis, a design equation was developed that produced conservative results for all of the specimens tested.

Book Shear Strengthening of Reinforced Concrete Beams Using Fiber Reinforced Polymer Wraps

Download or read book Shear Strengthening of Reinforced Concrete Beams Using Fiber Reinforced Polymer Wraps written by and published by . This book was released on 1998 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies have shown that fiber-reinforced polymer (FRP) wraps can improve the capacity of rectangular beam sections. This technology has potential application to highway bridges that may have less shear capacity than flexural capacity or require added load capacity to handle current traffic demands. Compared with steel repair materials FRP offers several benefits, such as corrosion resistance and field-workability. Several studies have investigated the use of externally bonded FRP sheets to improve strength and stiffness of reinforced concrete (R/C) beams, but most have addressed flexural strength, not shear. The objective of the current study was to test the effectiveness of FRP wraps in repairing full-scale prestressed high-strength concrete joists fabricated with insufficient shear reinforcement. Four prestressed high-strength concrete tee-beams (joists) with integral web openings were tested. Two of the joists were repaired or upgraded with FRP wraps to improve shear performance and two were used as control specimens. Performance criteria were specified, and standard structural engineering practice for shear design was employed to determine wrap thickness. The results of the tests indicate that significant increases in the shear strength of R/C beams with insufficient shear capacity can be achieved by proper application of FRP wraps.

Book Shear Strengthening of Reinforced Concrete Beams with Carbon Fiber Reinforced Polymer  CFRP  Under Fatigue and Sustained Loading Applications

Download or read book Shear Strengthening of Reinforced Concrete Beams with Carbon Fiber Reinforced Polymer CFRP Under Fatigue and Sustained Loading Applications written by Christopher Neil Satrom and published by . This book was released on 2011 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Four specimens were tested to evaluate the shear performance of beams with carbon fiber reinforced polymer (CFRP) laminates and CFRP anchors under fatigue and sustained loading applications. The specimens consisted of 24-in. deep T-beams that were constructed and tested at Phil M. Ferguson Structural Engineering Laboratory at the University of Texas at Austin. The specimens were strengthened in shear with CFRP laminates anchored with CFRP anchors. One end of each specimen was strengthened using bonded CFRP laminates while the other end was strengthened using unbonded CFRP laminates. Two specimens were used for fatigue testing and two were used for sustained load testing. For each set of tests, one specimen was strengthened using CFRP laminates prior to cracking and one specimen was strengthened using CFRP laminates following the initial cracking of the specimen. The CFRP laminates showed no signs of deteriorations in strength during fatigue testing, with only small increases in strain occurring in the CFRP laminates during testing. After fatigue loading was completed, the specimens were monotonically loaded to failure. The failure loads were 5 to 15% lower than beams that were not subjected to fatigue loading. Sustained load tests were subjected to a constant midpoint load based on service load requirements for a period of 217 days. CFRP laminates performed well during sustained loading. CFRP strains increased slightly throughout testing, but no signs of deterioration were observed. For both types of tests, specimens strengthened using bonded CFRP laminates demonstrated an increased stiffness resulting in smaller crack widths and lower strains in the internal steel. These benefits were not as great in specimens strengthened after the initial cracking of the specimen.

Book Behaviour of Shear critical Reinforced Concrete Beams Strengthened with Fiber Reinforced Cementitious Mortar

Download or read book Behaviour of Shear critical Reinforced Concrete Beams Strengthened with Fiber Reinforced Cementitious Mortar written by Rizwan Azam and published by . This book was released on 2016 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extensive research has been conducted on strengthening of shear-critical reinforced concrete (RC) beams, particularly using fiber reinforced polymer (FRP) strengthening systems. This previous research has helped to better understand the behaviour of shear strengthening systems and has improved the performance of existing shear strengthening systems. However, there is still a potential to further improve upon the performance of existing shear strengthening systems. A cement-based composite system is an innovative strengthening system that has similar benefits (such as light weight, ease of installation and non-corroding) to FRP systems, but overcomes some of the draw backs (such as poor compatibility with concrete substrate, lack of vapour permeability and fire resistance) of using epoxy as bonding agent in FRP systems. A cement-based composite replaces the epoxy with cementitious mortar and the fiber sheets with fabric or grids. The current study presents the results of an experimental study conducted to investigate the effectiveness of cement-based composite systems in comparison to an existing epoxy-based system (carbon fiber reinforced polymer, CFRP) to strengthen shear-critical RC beams. Two types of cement-based systems were investigated in this study: carbon fiber reinforced polymer (CFRP) grid embedded in mortar (CGM) and carbon fabric reinforced cementitious mortar (CFRCM). The experimental study consisted of two phases. Phase I focused on flexural testing of seven medium-scale shear-critical reinforced concrete (RC) beams. The objective of this phase was to evaluate the potential of FRCM shear strengthening. The test variables included the type of FRCM (carbon FRCM or CFRCM and glass FRCM or GFRCM) and the strengthening scheme (side bonded vs. U-wrapped). Phase II was designed based on results of Phase I study, and it consisted of flexural testing of twenty (20) large-scale shear-critical RC beams strengthened with cement-based systems. The objective of this phase was to evaluate the effectiveness of the two types of cement-based strengthening systems in comparison to the existing epoxy-based FRP system. The test variables included: the shear span to depth ratio (slender and deep beams), amount of internal transverse steel reinforcement and type of strengthening system (CFRCM, CGM and CFRP). The results showed that the cement-based systems (CFRP grid in mortar and CFRCM) performed better compared to the epoxy-based system (CFRP sheet) in terms of the increase in shear capacity relative to the ultimate strength of the strengthening systems. The results also showed that the bond of cement-based system with the concrete substrate was sufficient that u-wrapping may not be required; the studied side-bonded systems did not exhibit signs of premature debonding. This is in contrast to most FRP fabric strengthening systems were u-wrapping is required for adequate bond. In addition, cement-based systems exhibited a better ability to control diagonal (shear) crack widths compared to the epoxy-based system tested, providing a greater reduction in diagonal crack width despite the relative lower ultimate strength and stiffness of the cement-based systems. Shear strengthening resulted in reduced shear strength contribution from stirrups. The strengthened beams with stirrups exhibited steeper shear cracks compared to control unstrengthened beams with stirrups. Similarly, the presence of stirrups reduces the shear strength contribution from strengthening. Again, the addition of stirrups results in steeper shear cracks which intersect fewer fibers tows in the strengthening system which results in a reduced shear strength contribution from strengthening layer. Lastly, the existing models to predict the ultimate load of strengthened shear-critical RC beams were evaluated and modifications to these methods were proposed.

Book Effect of Shear Span to depth Ratio on Shear Strengthening of Beams with CFRP

Download or read book Effect of Shear Span to depth Ratio on Shear Strengthening of Beams with CFRP written by Bilal Khalil and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research investigates the often-neglected area of enhancing the shear strength of reinforced concrete beams with Carbon Fiber Reinforced Polymer (CFRP) composites, specifically focusing on the impact of the Shear Span-to-Depth (a/d) ratio. Shear capacity is a crucial factor in structural design, and the use of CFRP composites provides a promising solution for its improvement. However, there is still a research gap in optimizing the effectiveness of CFRP, particularly when it comes to the a/d ratio.To achieve this, an experimental program was executed which involved testing two concrete beams with varying a/d ratio as part of a comprehensive research plan. The CFRP rods were bonded externally to the shear critical regions of the beams to assess their effectiveness in improving shear capacity.The study examined the impact of varying Shear Span-to-Depth ratios on reinforced concrete beams. a/d ratio of four performed best, emphasizing its significance in optimizing real-world performance.

Book Shear Strengthening of Reinforced and Prestressed Concrete Beams Using Carbon Fiber Reinforced Polymer  CFRP  Sheets and Anchors

Download or read book Shear Strengthening of Reinforced and Prestressed Concrete Beams Using Carbon Fiber Reinforced Polymer CFRP Sheets and Anchors written by Yungon Kim and published by . This book was released on 2012 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability to quickly apply carbon fiber reinforced polymer (CFRP) materials with a minimum of disruption to the use of a structure and with virtually no change in the geometry or weight of the element makes CFRP a viable and attractive material for strengthening existing elements. However, without adequate anchorage of CFRP sheets to the concrete surface, premature failures by debonding of the CFRP from the concrete significantly limit the capacity of CFRP strengthening systems. The objective of the study was to demonstrate the feasibility of using anchored CFRP for shear strengthening of large bridge girders or supporting elements. An extensive experimental program was undertaken on several full-scale T-beams and I girders to achieve project objectives. CFRP anchors used in the study performed well and were able to develop the full capacity of CFRP sheets thereby precluding debonding failures. Studied anchored CFRP systems were thus able to generate significant shear strength gains of up to 50 percent of the unstrengthened beam capacity. Experimental results, installation procedures for CFRP sheets and anchors, specifications for fabrication and installation of CFRP anchors, and anchored CFRP shear design guidelines are presented.

Book Strengthening and Repairing of RC Deep Beams Using CFRP and GFRP

Download or read book Strengthening and Repairing of RC Deep Beams Using CFRP and GFRP written by Amr Hussein A. Zaher and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are many reasons to upgrade an existing structure such as building code changes, accidents, design errors or building use changes. Few years ago the construction industry began using fibre reinforced polymer (FRP) for structural reinforcement, typically in combination with other building materials such as wood, steel and concrete. FRP show multiple attractive properties, such as low weight to strength ratio, non-corrosiveness high fatigue strength, and case of application. This study investigated different techniques to improve the performance of RC deep beams under two concentrated vertical loads using advanced composite materials (CFRP and GFRP sheets). The primary aim of this research was to study the behaviour of deep beams strengthened and repaired in shear using carbon and glass fibres.Thirteen RC deep beam specimens were simply supported with span lengths L=1500 mm and cross sections 140 x 450 mm. The tested beams were subjected to the effects of two concentrated loads with spacing of 560, 360 and 160 mm and were divided into five groups. The test results show that the deep beams strengthened by CFRP sheets & GFRP sheets provided improvement in ultimate loads. The maximum increase in ultimate loads reached 106% & 81% respectively and the decrease in deflection for beams was attributed to the type, configurations and orientation of the FRP sheets. An analytical model was done based on code equations to predict the deformational behaviour of RC deep beams shear-strengthened with FRP composites , and obtain the failure loads by using three codes equations and compare the results with the experimental results. The proposed analytical model gave good compliance with the experimental results.