Journal articles: 'FRP-retrofitted concrete'

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Li, Peng, Ya Ping Peng, and Er Lei Yao. "Restoring Force Model of Joints of RC Frame Retrofitted by FRP." Applied Mechanics and Materials 256-259 (December 2012): 693–96. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.693.

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In order to evaluate the seismic performance of reinforced concrete (RC) frames retrofitted by FRP, the experiment of RC frames retrofitted at joints by FRP was carried out. The enhancement in seismic performance of the retrofitted frames is evaluated in hysteretic performance, bearing capacity, stiffness degradation and energy dissipation. And the strengthening effect of the frame retrofitted by CFRP and C/GFRP was compared in the experiment. The restoring force model of RC frame joints retrofitted with FRP was proposed and ranges of the characteristic parameters were determined. The equation of restoring force model for joints strengthened by C/GFRP was suggested. The result show that seismic performance of RC frame retrofitted by FRP based on joints can be improved remarkably. The restoring force model which proposed can be used in seismic elasto-plastic analysis of RC frame structure retrofitted by FRP and practical engineering seismic retrofitting design by FRP.

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Awari, Shloka. "Review Paper on Effective Methods for The Retrofitting of Reinforced Concrete Structures." International Journal for Research in Applied Science and Engineering Technology 10, no. 6 (June 30, 2022): 1956–59. http://dx.doi.org/10.22214/ijraset.2022.44203.

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Abstract: Existing structures are retrofitted to make them more bearable for earthquakes, earth motion, and other natural disasters. Many existing reinforced concrete elements throughout the world are in desperate need to be rehabilitated, repaired, or replaced due to degradation caused by a variety of causes such as corrosion, lack of detail, and failure of beam-column joint bonding, among others. The construction industry has embraced Fibre Reinforced Polymer (FRP) composites as a promising alternative for repairing and strengthening RCC structures. This study observes reinforced concrete beams that have been externally retrofitted with FRP. The goal of this research is to summarise the behaviour beams after they have been retrofitted with FRP. The main objective of the research is to repair structurally weak elements and make them useful in flexure and shear.

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Suliman, Nurul Huda, A. Abu Bakar, Siti Hawa Hamzah, and Norzahiah Shahar. "Crack Behaviour of Retrofitted Pre-Tensioned Concrete Beam." Applied Mechanics and Materials 752-753 (April 2015): 605–9. http://dx.doi.org/10.4028/www.scientific.net/amm.752-753.605.

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Crack is a common cause of the degradation of concrete and may affect its structural durability. In order to ensure the bridge is safe utilized in anticipated period of their future service, a proper maintenance process and procedure should be taken. Therefore in this study, static load test were performed on a pre-tensioned (PRT) concrete beam to investigate crack behaviour before and after retrofitting process as well as to determine the effectiveness of the retrofitting method. A control beam named PRTB1 will fully loaded until fail to determine its maximum load capacity and critical load of the beam. Hence another beam named PRTB-FRP will be loaded until it reached it critical load capacity before retrofitted using Fiber Reinforced Polymer (FRP) plates located beneath the centre of the beam. After the retrofitting process PRTB-FRP will be put again under the static load. The load capacity of PRTB-FRP increased compared to PRTB1 with some improvement in crack propagation behaviour after retrofitted.

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Lin, Xiaoshan, and Y. X. Zhang. "Nonlinear Finite Element Analysis of FRP-Strengthened Reinforced Concrete Panels Under Blast Loads." International Journal of Computational Methods 13, no. 04 (July 4, 2016): 1641002. http://dx.doi.org/10.1142/s0219876216410024.

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A finite element model is developed in this paper for numerical modeling of the structural responses of FRP-strengthened reinforced concrete panels under blast loading. Strain rate effects for concrete in tension and compression, steel reinforcements and FRP sheets are taken into account in the finite element model. The commercial explicit hydrocode LS-DYNA is employed to carry out the numerical analysis. The proposed finite element model is validated by comparing the computed results of a conventional reinforced concrete panel and FRP-strengthened reinforced concrete panels under blast loading with the test data from the literature. In addition, the effects of FRP thickness, retrofitted surface, standoff distance and the charge mass on the blast resistance of FRP-strengthened reinforced concrete panels are investigated in this paper.

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Sheikh, Shamim A., and S. Mukhtar Homam. "Resilience and sustainability of FRP-retrofitted concrete structures." International Journal of Sustainable Materials and Structural Systems 5, no. 1/2 (2021): 35. http://dx.doi.org/10.1504/ijsmss.2021.10038716.

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Homam, S. Mukhtar, and Shamim A. Sheikh. "Resilience and sustainability of FRP-retrofitted concrete structures." International Journal of Sustainable Materials and Structural Systems 5, no. 1/2 (2021): 35. http://dx.doi.org/10.1504/ijsmss.2021.115785.

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Ming Zhao, Ming, Yongtao Dong, Yang Zhao, Adam Tennant, and Farhad Ansari. "Monitoring of Bond in FRP Retrofitted Concrete Structures." Journal of Intelligent Material Systems and Structures 18, no. 8 (March 29, 2007): 853–60. http://dx.doi.org/10.1177/1045389x06074571.

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Hadigheh, S. A., S. S. Mahini, and M. R. Maheri. "Seismic Behavior of FRP-Retrofitted Reinforced Concrete Frames." Journal of Earthquake Engineering 18, no. 8 (May 22, 2014): 1171–97. http://dx.doi.org/10.1080/13632469.2014.926301.

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Van Cao, Vui, and Son Quang Pham. "FRP Composite in Mitigating Seismic Risk of RC Structures in Near-Fault Regions with/without Aftershocks." Advances in Civil Engineering 2020 (July 8, 2020): 1–17. http://dx.doi.org/10.1155/2020/2847027.

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The literature related to earthquakes and fibre reinforced polymer (FRP) retrofitting can be divided into two main categories: (1) the applications of FRP to retrofit structures subjected to single traditional earthquakes and (2) the effects of mainshock-aftershock sequences on original structures (without FRP retrofitting). Research on using FRP to mitigate the risk of pulse-type mainshock-aftershock sequences for reinforced concrete (RC) structures located in near-fault regions is hardly found in the literature and is thus the aim of this study. To achieve this aim, a four-storey RC frame, near-fault mainshocks, and seismic sequences were selected. The frame was retrofitted using FRP wraps at plastic hinge locations. Nonlinear time history and damage analyses of the original and FRP-retrofitted frames subjected to these near-fault mainshocks and seismic sequences were conducted. The results showed that aftershocks significantly increase the damage indices of the frames, shifting the damage state of the original frame from severe damage to collapse and the damage state of the FRP-retrofitted frame from light damage to moderate damage. FRP retrofitting successfully reduced the risk of seismic sequences by reducing the damage two levels, shifting the damage state of the original frame from collapse to moderate damage.

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TAN, K. H., and T. BALENDRA. "RETROFIT OF EXISTING BUILDINGS FOR EARTHQUAKE RESISTANCE." Journal of Earthquake and Tsunami 01, no. 02 (June 2007): 161–69. http://dx.doi.org/10.1142/s1793431107000110.

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Buildings sited on soft soils are sometimes subjected to tremors due to earthquakes occurring some 400 to 700 kilometers away as a result of the amplifying effect of soft soils on low-frequency, long-distance waves. This study focuses on the seismic vulnerability of existing reinforced concrete (RC) buildings in Singapore that are designed primarily for gravity loads, and examines the use of externally bonded glass fiber-reinforced polymer (FRP) systems in retrofitting these buildings to resist lateral forces due to seismic action. Two case studies were considered: (1) a four-story frame building, representing typical low-rise buildings; and (2) a 25-story shear wall-frame building, representing typical high-rise buildings. Pushover tests were carried out correspondingly on 1/2-scale sub-frames and 1/5-scale shear walls. The one-and-a-half bay, two-storey frame specimens represent the critical part of the low-rise building while the I-shaped wall specimens represent the lower critical 2.6 stories of the high-rise building. Test results revealed a strong column–weak beam failure mechanism for both the un-retrofitted and retrofitted frames. The retrofitted frame was 30 percent higher in ultimate strength but 12 percent lesser in ultimate drift ratio compared to the un-retrofitted frame. For the wall specimens, sudden failure of the un-retrofitted shear wall was observed at the base of the side walls due to shear. Failure of the retrofitted wall was however more ductile with FRP debonding, followed by concrete crushing and FRP rupture at the compressive base of the side wall. The ultimate load capacity and lateral displacement of the retrofitted wall increased respectively by 45 and 66 percent.

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Sun, Wen Bin, Qiang Qiang Zhu, and Wei Zhong He. "Experimental Study of the Carbon FRP Retrofitted Reinforced Concrete Panels under Explosion." Applied Mechanics and Materials 405-408 (September 2013): 831–34. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.831.

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Explosions, such as a bomb explosion and a gas explosion, can cause catastrophic damage on the buildings. In fact, an explosion may result in large dynamic loads, greater than the original design loads, of many structures. Two RC specimens were tested under explosive loading. The first specimen was used as a control for the experiment, while the other was retrofitted with 6 near surface mounted (NSM) Carbon FRP strips on each face. Both specimens were subjected to a 60g Pentolite at stand off distances of 0.6m. The aim of this experiment was to observe and compare the behavior of the two specimens, and their ability to resist blast loads respectively. Of particular interest was the response of the retrofitted RC specimens NSM Carbon FRP. The experimental results showed that NSM retrofitting with Carbon FRP is an effective way to provide extra strength when retrofitting against blast loading.

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Dong, Jing, Junhai Zhao, and Dongfang Zhang. "Numerical Evaluation of Reinforced Concrete Columns Retrofitted with FRP for Blast Mitigation." Advances in Civil Engineering 2020 (September 16, 2020): 1–14. http://dx.doi.org/10.1155/2020/8884133.

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Fiber reinforced polymer (FRP) material is commonly applied in retrofitting structures due to the advantages of high strength and well corrosion resistance. Previous studies indicated that retrofitting with FRP sheet was an effective way for protecting the existing structures to resist the blast loads, but little research made comprehensive comparison study on the blast response of RC columns with different retrofitting strategies. This paper proposed a series of FRP retrofitting strategies and evaluated their effect on blast mitigation using numerical analysis approach. Comparison studies were conducted on the effect of FRP type, FRP thickness, and retrofitting mode on blast mitigation. A finite element model of RC columns retrofitted with FRP under blast loading was developed. The model considered the strain rate effect of steel and concrete and the orthotropic property of FRP composites. The reliability of the proposed model was validated against the data from a field blast test. Based on the verified model, the blast responses of RC columns with different retrofitting strategies were numerically investigated. According to the result analysis, appropriate FRP type, FRP thickness, retrofitting mode, and retrofitting length were recommended.

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Mahrenholtz, Philipp, Jae-Yeol Cho, Ja-Min Park, and Rolf Eligehausen. "Characterization of Shear Strength of FRP Anchors." MATEC Web of Conferences 199 (2018): 09008. http://dx.doi.org/10.1051/matecconf/201819909008.

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A critical performance aspect of FRP retrofitted concrete elements is the bonding of the FRP sheet to the concrete surface. In general, the performance is limited by the debonding of the loaded FRP sheets from the concrete surface. One method to delay debonding and enhance the capacity is the use of FRP anchors which interlock the FRP sheet to the concrete body. FRP anchors are made of rolled FRP fibres epoxied into in predrilled boreholes. There are a considerable number of studies on FRP strengthening methods available, and also FRP anchors attract more attention of the research community recently. However, to date FRP anchors were tested in a system together with the FRP sheet attached to the concrete, inhibiting the development of general design models. Moreover, the anchor behaviour was never tested for cyclic loads, though most applications are for seismic retrofitting schemes and cyclic shear loading generally results in reduced load capacity due to fatigue failure. To overcome the deficit in knowledge, shear tests on various FRP anchors were carried out. For these tests, FRP anchors were installed in concrete specimens on a separating steel section. The FRP anchor was then directly loaded to determine the capacity of the isolated component. This paper describes the testing approach and procedure. Details on the experimental results for static tests are presented and an outlook on seismic tests is given.

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Buyukozturk, Oral, and Brian Hearing. "Failure Behavior of Precracked Concrete Beams Retrofitted with FRP." Journal of Composites for Construction 2, no. 3 (August 1998): 138–44. http://dx.doi.org/10.1061/(asce)1090-0268(1998)2:3(138).

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Nguyen, Huy Q., Tri N. M. Nguyen, Do Hyung Lee, and Jung J. Kim. "The Effects of Bond–Slip Laws on the Debonding Failure and Behavior of Flexural Strengthened RC Slabs in Hybrid FRP Retrofit Systems." Materials 15, no. 21 (October 24, 2022): 7453. http://dx.doi.org/10.3390/ma15217453.

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The hybrid retrofit system using FRP and concrete overlay applied on the top of slabs has proven effective in strengthening and overcoming logistical constraints, compared with conventional strengthening techniques using externally bonded composite materials to the underside of the slabs. Nevertheless, the performance of retrofitted slabs is governed by debonding failure due to the low bond strength between CFRP and concrete overlay. Thus, this study investigates the behavior of flexural strengthened slabs with FRP retrofit systems and the effect of bond–slip laws on debonding failure. Firstly, two full-scale RC slabs with and without a retrofit system were tested in a four-point bending setup as the control specimens. Then, the same retrofitted slab was simulated by utilizing the commercial program ABAQUS. A sensitivity analysis was conducted to consider the influence of bond–slip laws to predict the failure mechanism of the retrofitted slabs based on load–deflection relationships. The results showed that the strengthened slab enhanced the load-carrying capacity by 59%, stiffness by 111%, and toughness by 29%. The initial stiffness of 0.1K0 and maximum shear stress of 0.13τmax, compared with the corresponding values of Neubauer’s and Rostasy’s bond–slip law, can be used to simulate the global response of the retrofitted slab validated by experiment results.

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Jasmine, N., S. Hemavathi, B. N. Brinila Bright, and M. B. Shanmuharajan. "Experimental Study on Retrofitted RC T-BEAM Using FRP." Volume 5 - 2020, Issue 8 - August 5, no. 8 (September 12, 2020): 1444–48. http://dx.doi.org/10.38124/ijisrt20aug476.

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Retrofitting is the method of strengthening of accessible structure to build them more challenging to earthquake activity etc. Fiber Reinforced Polymer (FRP) composite was acknowledged in the building trade as alternate for repair and for accelerating the potency of RCC. This paper presents an investigational study on retrofitting of reinforced concrete beams using FRP

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Bedirhanoglu, Idris. "Retrofitting of Shear Compression Failure-Critic Short Columns with a New Technique." Buildings 12, no. 12 (December 19, 2022): 2266. http://dx.doi.org/10.3390/buildings12122266.

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One of the reasons that cause the collapse of buildings is deficient short columns, which need to be retrofitted to prevent the collapse of the building in a potential earthquake. External reinforced concrete (RC), steel plates, and fiber-reinforced polymer (FRP) jacketing are standard retrofitting methods to retrofit columns to increase their shear capacity. However, in compression shear failure, the effectiveness of steel and FRP jacketing is quite limited due to the premature buckling of the FRP and steel material. On the other hand, RC jacketing is not practical because it requires more labor and covers more architectural places. Thus, the main motivation of this study is to present the effectiveness of a new method to retrofit short columns, including those with dominated shear compression failure. For this purpose, HSPRCC (high-performance steel plate-reinforced cementitious composite) was adapted to retrofit such short columns. This method is a combination of high-performance concrete and perforated steel plates. Short-column specimens representing existing RC buildings were retrofitted using the HSPRCC and tested. Perforated steel plates anchored to the specimen by steel bolts and repair mortar are used as a matrix. The retrofitted specimens were found to exhibit much better performance both in terms of shear strength and deformation capacity. It was also observed that the retrofitting method is effective in contributing to increasing the compression shear capacity.

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Li, Weiwen, Wei Liu, Xu Yang, and Feng Xing. "Experimental Study on FRP-to-Concrete Bonded Joints with FRP Sheet Anchor System." Advances in Materials Science and Engineering 2020 (March 18, 2020): 1–13. http://dx.doi.org/10.1155/2020/2514313.

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Fiber-reinforced polymer (FRP) has been widely used for retrofitting and strengthening concrete structures over the past two decades. Because concrete members retrofitted by externally bonded FRP sheets can fail prematurely in debonding because of the fracture between FRP and concrete, FRP tensile strength cannot be fully utilized in engineering practices. Numerous useful investigations have been conducted to develop effective anchor systems to restrict FRP debonding. Thus, an FRP sheet-anchor system was developed and observed to be one of the most effective and convenient anchor systems. The FRP sheet-anchor system is applied to reinforced concrete beams strengthened with U-wrapping and side-bonded FRP configurations in few design guidelines. However, only a few investigations have focused on the failure mechanism of the FRP sheet-anchor system in the existing literature. Therefore, the main objective of this study is analyzing the effect of the carbon FRP (CFRP) sheet-anchor system on the bonding behavior of the CFRP-concrete interface, particularly the effect of the width and stiffness of the CFRP sheet-anchor system. In addition, the anchor-strengthened stage is defined by the load-slip response, which is different from that of specimens without the CFRP sheet-anchor system. Based on the experimental results, three linear stage models of the bond-slip constitutive relationship are proposed in this study.

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Cao, Vui Van, and Son Quang Pham. "Damage-Based Seismic Retrofitting Approach for Nonductile Reinforced Concrete Structures Using FRP Composite Wraps." Advances in Civil Engineering 2020 (May 30, 2020): 1–21. http://dx.doi.org/10.1155/2020/7564684.

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Applying similar amount of fibre reinforced polymer (FRP) for all plastic hinge locations in a structure is not an ideal approach as damage occurring at these critical locations may vary considerably. Building owners also always want to keep FRP retrofitting cost and associated interruption to a minimum. In this context, the current paper proposes an FRP retrofitting approach, in which FRP is selectively distributed based on the distribution of seismic damage in structures. The proposed approach, characterized by both quantitative and qualitative criteria, is simple but very effective in simultaneously reducing the seismic damage, amount of FRP to be used, and time of installation. For the considered cases of low- and mid-rise nonductile building structures, the FRP amount reduced approximately by 31% compared to the cases in which FRP was evenly distributed, leading to lower installation cost and less interruption time. Interestingly, although 31% FRP was saved, the damage indices of the FRP retrofitted frames were significantly lower than those in cases of even FRP distribution because FRP effectively served for critical locations. Due to its simplicity and technical/economical effectiveness, the proposed FRP retrofitting approach can be useful for engineering practice.

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Zheng, R., P. Zohrevand, H. Erdogan, and A. Mirmiran. "Performance of frp-retrofitted concrete bridge columns under blast loading." International Journal of Computational Methods and Experimental Measurements 2, no. 4 (December 31, 2014): 346–61. http://dx.doi.org/10.2495/cmem-v2-n4-346-361.

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Handiana Devi, Rida, Senot Sangadji, and Halwan Alfisa Saifullah. "Fragility curve of low-to-mid-rise concrete frame retrofitted with FRP." E3S Web of Conferences 156 (2020): 03006. http://dx.doi.org/10.1051/e3sconf/202015603006.

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In order to achieve satisfactory global seismic behaviour of a concrete fame structure and to prevent undesirable local failures of its structural element, local strengthening of structural members by means of FRP wrap is one of the cost effective retrofitting strategy. This FRP wrapped column will increase the ductility of the element as well as the capacity that in turn will allow attaining more energy dissipating global performance. This on-going research aims to demonstrate the seismic performance of Low-to-Mid-Rise Concrete Frame retrofitted by FRP wrap in several configurations. The fragility curves of the structure before and after to local strengthening will be developed and analysed. Fragility curve will describe the probability of the structure that will exceed certain damage states given the ground shaking intensity during its service life. This curve allows evaluation for the retrofitting strategy is carried out rationally.

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Chandra, Anuj. "Retrofitting of the Structure using Composite Material FRP." International Journal for Research in Applied Science and Engineering Technology 9, no. 10 (October 31, 2021): 1242–52. http://dx.doi.org/10.22214/ijraset.2021.38601.

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Abstract: Retrofitting is the process of modifying existing structures in order to increase their performance and durability. Dayto-day concrete structures may require retrofitting owing to a variety of issues such as corrosion, detailing laceration, and bonding failure, among others. Fiber reinforced polymers (FRP) are a relatively recent method used in retrofitting to strengthen and repair structural damage. The goal of this research is to go over the advantages, applications, and major challenges of employing FRP as a composite material. To begin, the paper will describe the principles of FRP composites, including the definition and description of components such as fibers and matrices. We have collected significant information properties of composite materials and uses in retrofitting process to improve strength and durability of the structure and studying the behavior of reinforced concrete structure strengthened (retrofitted) using composite materials in this paper on Retrofitting of the Structure using Composite material FRP. Our research included a fact study and prediction analysis of key records and data connected to our research purpose, which assisted us in reaching a conclusion on Retrofitting of the Structure Using Composite Material FRP and also comparative analysis between steel retrofitting and composites materials (FRP) retrofitting of the existing structure. Keywords: Retrofitting, FRP, Concrete reinforced, Matrix, Rehabilitation

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Elhamnike, Seyed Mehrdad, Rasoul Abbaszadeh, Vahid Razavinasab, and Hadi Ziaadiny. "Behavior and modeling of post-heated circular concrete specimens repaired with fiber-reinforced polymer composites." Advances in Structural Engineering 25, no. 3 (December 9, 2021): 541–51. http://dx.doi.org/10.1177/13694332211058532.

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Exposure of buildings to fire is one of the unexpected events during the life of the structure. The heat from the fire can reduce the strength of structural members, and these damaged members need to be strengthened. Repair and strengthening of concrete members by fiber-reinforced polymer (FRP) composites has been one of the most popular methods in recent years and can be used in fire-damaged concrete members. In this paper, in order to provide further data and information about the behavior of post-heated circular concrete columns confined with FRP composites, 30 cylindrical concrete specimens were prepared and subjected under four exposure temperatures of 300, 500, 700, and 900. Then, specimens were repaired by carbon fiber reinforced polymer composites and tested under axial compression. Results indicate that heating causes the color change, cracks, and weight loss of concrete. Also, with the increase of heating temperature, the shape of stress–strain curve of FRP-retrofitted specimens will change. Therefore, the main parts of the stress–strain curve such as ultimate stress and strain and the elastic modulus will change. Thus, a new stress–strain model is proposed for post-heated circular concrete columns confined by FRP composites. Results indicate that the proposed model is in a good agreement with the experimental data.

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Amini Pishro, Ahad, Shiquan Zhang, Zhengrui Zhang, Yana Zhao, Mojdeh Amini Pishro, Lili Zhang, Qihong Yang, and Victor Postel. "Structural Behavior of FRP-Retrofitted RC Beams under Combined Torsion and Bending." Materials 15, no. 9 (April 29, 2022): 3213. http://dx.doi.org/10.3390/ma15093213.

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Fiber-reinforced polymers (FRPs) retrofit reinforced concrete (RC) structures. ABAQUS finite element software was used to perform numerical parametric analysis on a group of RC beams in this research. All specimens were retrofitted by FRP strips as an external retrofitting and experimentally tested up to previous researchers’ failure points. The range of subjects examined in these RC beams included cracking torque, ultimate torque, angle of twist, and the effect of using FRP on these subjects. We applied artificial neural networks (ANNs) to predict the structural behavior of RC beams under combined torsion and bending to develop the research accuracy. After testing, the ANN results were compared with the ABAQUS results. Consequently, a reasonable examination of the determined mathematical and trial results confirmed this study’s logical accuracy in predicting retrofitted RC beams’ structural behavior under combined loading.

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Liu, Xiangdong, Antonio Nanni, and Pedro F. Silva. "Rehabilitation of Compression Steel Members Using FRP Pipes Filled with Non-Expansive and Expansive Light-Weight Concrete." Advances in Structural Engineering 8, no. 2 (April 2005): 129–42. http://dx.doi.org/10.1260/1369433054038029.

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This paper presents the experimental and analytical evaluation of the feasibility of a proposed fiber reinforced polymer (FRP) retrofit method to strengthen corroded steel columns. This method consists of two steps: (1) wrapping the corroded steel column with an FRP jacket, and (2) filling the jacket with expansive light-weight concrete. Seven steel columns were tested in the laboratory including five strengthened columns with the proposed technique. The first two were used as control units where one was a virgin shape and the second was notched in the center zone to simulate the loss of section due to corrosion. The remaining five were all notched, and confined with FRP composite pipes within the simulated corroded zone and subsequently filled with light-weight concrete. All specimens were axially loaded to failure while strain and displacement readings were measured to demonstrate the feasibility of this repair concept. Test results show that the proposed FRP retrofit method for steel columns can be successfully applied. Furthermore, an analytical model was developed that can predict the load capacity of the FRP retrofitted steel column.

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Rhim, Hong C., Sang Kyun Woo, and Young Chul Song. "Detection of Debonding in Concrete Members Retrofitted with FRP Using Electromagnetic and Ultrasonic Methods." Key Engineering Materials 321-323 (October 2006): 390–93. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.390.

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Microwave and ultrasonic methods have been used for the detection of debonding between concrete and fiber-reinforced plastic (FRP). To determine the capability of the microwave method in detecting thin delamination between two materials of concrete and FRP, concrete specimens are made with the dimensions of 600 mm (length) x 600 mm (width) x 50 mm (depth). Specimens have artificial delamination of 5 and 10 mm thick Styrofoam, which represent debonding in structures. Then, the specimens are partially covered with 1.5 mm thick FRP on the top of 3 mm thick epoxy. A horn antenna with a center frequency of 15 GHz and a frequency bandwidth of 10 GHz is used for the measurements. By transmitting and receiving microwave signals from the horn antenna, differences have been detected for the different types of the targets. Also, measurements using ultrasonic method at 5 kHz have been made on the same series of specimens. This work is directed toward a development of an effective and practical microwave based non-destructive evaluation methodology for the detection and quantification of damages in FRP-covered reinforced concrete members in bridges and buildings.

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Bae, B. I., B. K. Park, Hyun Ki Choi, and Chang Sik Choi. "Retrofitting Effect of Unreinforced Masonry Walls Using FRPs." Key Engineering Materials 452-453 (November 2010): 765–68. http://dx.doi.org/10.4028/www.scientific.net/kem.452-453.765.

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Unreinforced masonry buildings have significant portion of existing and historical buildings around the world. Recent earthquakes have shown the needs of seismic retrofitting for these types of buildings. There are many types of retrofitting materials for URM(unreinforced masonry buildings) such as shotcrete, ECC and FRPs. Many engineers use many types of fiber reinforced polymers because these types of material enhance the shear strength of wall without expansion of wall sectional area and additional weight of total structure. However, the complexity of mechanical behavior of masonry shear wall and the lack of experimental data of masonry wall which was retrofitted by FRPs may cause the problem that engineers hard to determine the retrofitting level. Determining and providing the information for retrofitting effect of FRPs for masonry shear wall, this paper investigate in-plane shear behavior of URM and retrofitted masonry shear walls using two types of different FRP materials. Specimens were designed to idealize the wall of low rise apartment which was built in 1970s Korea with no seismic reinforcements and have 1 aspect ratio. Retrofitting materials were carbon FRP and Hybrid sheet which have different elastic modulus and ultimate strain. Consequently, this study will evaluate the structural capacity of masonry shear wall and retrofitting effect of FRP sheet for in plane shear behavior comparing with evaluation method for reinforced concrete beam which was retrofitted by FRPs.

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Xu, Ying, Soonkyu Hwang, Qingyuan Wang, Donggun Kim, Congcong Luo, Jinyeol Yang, and Hoon Sohn. "Laser active thermography for debonding detection in FRP retrofitted concrete structures." NDT & E International 114 (September 2020): 102285. http://dx.doi.org/10.1016/j.ndteint.2020.102285.

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Kim, Ho Jin, Na Hyun Yi, Sung Bae Kim, Jin Won Nam, Ju Hyung Ha, and Jang-Ho Jay Kim. "Debonding failure analysis of FRP-retrofitted concrete panel under blast loading." Structural Engineering and Mechanics 38, no. 4 (May 25, 2011): 479–501. http://dx.doi.org/10.12989/sem.2011.38.4.479.

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Zhang, Pengpeng, and Xinsheng Xu. "Size effect of concrete column retrofitted by fiber-reinforced polymer (FRP)." IOP Conference Series: Earth and Environmental Science 61 (April 2017): 012060. http://dx.doi.org/10.1088/1755-1315/61/1/012060.

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Deng, Jun, Yifeng Zheng, Yi Wang, Tonghua Liu, and Hui Li. "Study on Axial Compressive Capacity of FRP-Confined Concrete-Filled Steel Tubes and Its Comparisons with Other Composite Structural Systems." International Journal of Polymer Science 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/6272754.

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Concrete-filled steel tubular (CFST) columns have been widely used for constructions in recent decades because of their high axial strength. In CFSTs, however, steel tubes are susceptible to degradation due to corrosion, which results in the decrease of axial strength of CFSTs. To further improve the axial strength of CFST columns, carbon fiber reinforced polymer (CFRP) sheets and basalt fiber reinforced polymer (BFRP) sheets are applied to warp the CFSTs. This paper presents an experimental study on the axial compressive capacity of CFRP-confined CFSTs and BFRP-confined CFSTs, which verified the analytical model with considering the effect of concrete self-stressing. CFSTs wrapped with FRP exhibited a higher ductile behavior. Wrapping with CFRP and BFRP improves the axial compressive capacity of CFSTs by 61.4% and 17.7%, respectively. Compared with the previous composite structural systems of concrete-filled FRP tubes (CFFTs) and double-skin tubular columns (DSTCs), FRP-confined CFSTs were convenient in reinforcing existing structures because of softness of the FRP sheets. Moreover, axial compressive capacity of CFSTs wrapped with CFRP sheets was higher than CFFTs and DSTCs, while the compressive strength of DSTCs was higher than the retrofitted CFSTs.

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32

Pohoryles, Daniel A., Jose Melo, and Tiziana Rossetto. "Combined Flexural and Shear Strengthening of RC T-Beams with FRP and TRM: Experimental Study and Parametric Finite Element Analyses." Buildings 11, no. 11 (November 6, 2021): 520. http://dx.doi.org/10.3390/buildings11110520.

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Due to inadequacies of reinforcement design in older structures and changes in building codes, but also the change of building use in existing structures, reinforced concrete (RC) beams often require upgrading during building renovation. The combined shear and flexural strengthening with composite materials, fibre-reinforced polymer sheets (FRP) and textile reinforced mortars (TRM), is assessed in this study. An experimental campaign on twelve half-scale retrofitted RC beams is presented, looking at various parameters of interest, including the effect of the steel reinforcement ratio on the retrofit effectiveness, the amount of composite material used for strengthening and the effect of the shear span, as well as the difference in effectiveness of FRP and TRM in strengthening RC beams. Significant effects on the shear capacity of composite retrofitted beams are observed for all studied parameters. The experimental study is used as a basis for developing a detailed finite element (FE) model for RC beams strengthened with FRP. The results of the FE model are compared to the experimental results and used to design a parametric study to further study the effect of the investigated parameters on the retrofit effectiveness.

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33

Altun, F., and F. Birdal. "Analytical investigation of a three-dimensional FRP-retrofitted reinforced concrete structure's behaviour under earthquake load effect in ANSYS program." Natural Hazards and Earth System Sciences 12, no. 12 (December 18, 2012): 3701–7. http://dx.doi.org/10.5194/nhess-12-3701-2012.

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Abstract. In this study, a 1:3 scaled, three-storey, FRP (Fiber Reinforced Polymer) retrofitted reinforced concrete model structure whose behaviour and crack development were identified experimentally in the laboratory was investigated analytically. Determination of structural behaviour under earthquake load is only possible in a laboratory environment with a specific scale, as carrying out structural experiments is difficult due to the evaluation of increased parameter numbers and because it requires an expensive laboratory setup. In an analytical study, structure was modelled using ANSYS Finite Element Package Program (2007), and its behaviour and crack development were revealed. When experimental difficulties are taken into consideration, analytical investigation of structure behaviour is more economic and much faster. At the end of the study, experimental results of structural behaviour and crack development were compared with analytical data. It was concluded that in a model structure retrofitted with FRP, the behaviour and cracking model can be determined without testing by determining the reasons for the points where analytical results are not converged with experimental data. Better understanding of structural behaviour is analytically enabled with the study.

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34

Zhou, Ying Wu, Ling Yi Wu, Li Li Sui, and Feng Xing. "Experimental Studies on the Mechanical Performances of Corroded Reinforced Concrete Columns Retrofitted with FRP." Applied Mechanics and Materials 405-408 (September 2013): 726–30. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.726.

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Due to the superiority of high corrosion resistance of FRP materials, more and more attentions have been attracted to the retrofitting of corroded reinforced concrete (RC) columns with FRP. This paper thus presents an experimental study on mechanical performances of corroded RC columns strengthened with FRP, focusing on the effects of different corrosion rates of the reinforcements and the retrofitting scheme. The effectiveness of externally bonded FRP to the corroded RC column to increase its load capacity and ductility is tested; the mechanical performances of the strengthened columns are theoretically investigated. The results indicate that the effectiveness of retrofitting the existing corroded RC columns with FRP jackets is much more significant than that of retrofitting the newly built columns with FRP jackets and externally wrapped with FRP jackets is much more effective to improving the structural performances of heavily corroded columns.

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35

Ghatte, Hamid F., Mustafa Comert, Cem Demir, and Alper Ilki. "Seismic Performance of Full-Scale FRP Retrofitted Substandard RC Columns Loaded in the Weak Direction." Applied Mechanics and Materials 847 (July 2016): 347–53. http://dx.doi.org/10.4028/www.scientific.net/amm.847.347.

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FRP confinement of sub-standard columns with low quality concrete, light transverse reinforcement and improper reinforcement detailing is widely accepted as an efficient retrofitting strategy. This paper introduces an improved method using carbon fiber reinforced polymers (CFRP) and external steel ties for seismic retrofitting of full-scale rectangular reinforced concrete columns loaded in their weak directions. Three cantilever columns with a cross-sectional aspect ratio of two (600 mm x 300 mm) are tested under constant axial load and reversed cyclic lateral loads. The columns are representative of existing substandard members with characteristics such as low concrete quality, low transverse reinforcement ratio, plain bars and high axial load level. The test results indicate that columns retrofitted with FRP jacketing and external steel ties significantly benefit from the applied retrofit scheme particularly in terms of ductility and energy dissipation. Additionally, the experimental results are compared with the performance predictions of seismic assessment and design documents.

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Jafari, Saeed, and Seyed Saeed Mahini. "Enhancement of the Fragility Capacity of RC Frames Using FRPs with Different Configurations at Joints." Polymers 15, no. 3 (January 25, 2023): 618. http://dx.doi.org/10.3390/polym15030618.

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This paper reports the results of an investigation into the effectiveness of different lengths of Fiber-Reinforced Polymer (FRP) sheets in retrofitting the joints of Reinforced Concrete (RC) frames to improve the fragility function of ordinary RC frames. Several 8-storey RC buildings were investigated through FE modelling. The accuracy of the FE models was verified using peer research results. Fragility curves of FRP-retrofitting joints of two referenced RC frames were carried out by OpenSees, through Incremental Dynamic Analysis (IDA) analysis under 22 far-field earthquake records from 0.1 g to 4.0 g (with 0.1 g interments), based on FEMA P-695. Two types of retrofitting methods, web and flange bonding, were modeled and studied. The results showed that the fragility capacity of the retrofitted RC frames was significantly improved. Moreover, frames with longer sheets of FRP showed increased performance. In the complete state, the range of probability of exceedance grew from 2–2.5 g to 3–3.5 g (nearly 1 g), whereas, in the minor state, this growth was nearly 0.05 g. However, the fragility function of the flange-bonding was enhanced at a higher rate compared with that of the web-bonding RC frames. Carbon Fiber-Reinforced Polymer (CFRP) and Glass Fiber-Reinforced Polymer (GFRP) materials improved the probability of exceedance of the complete state from 3 g to 4.5 g and 4.8 g in flange bonding frames. This enhancement for both types of frames was more significant when joints were retrofitted with 400 and 500 mm compared with 600, 700, and 800 mm. The midpoint of the PGA at the complete damage state in the web-bonding frame increased from 1.076 g to 1.664 g and in the flange-bonding frame retrofitted with GFRP and CFRP raised from 1.551 g to 2.769 and 3.076, respectively. The collapse margin ratio (CMR) indicates an acceptable improvement in the retrofitted frames. Overall, the rate of enhancement in fragility function from the original frame to the frame with 500 mm FRP was significant; however, the slope of this rate declined for longer FRP sheets. The fragility performance improvement resulted in controlling plastic hinging by FRPs.

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Chalioris, Constantin E., Adamantis G. Zapris, and Chris G. Karayannis. "U-Jacketing Applications of Fiber-Reinforced Polymers in Reinforced Concrete T-Beams against Shear—Tests and Design." Fibers 8, no. 2 (February 17, 2020): 13. http://dx.doi.org/10.3390/fib8020013.

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The application of externally bonded fiber-reinforced polymer (EB-FRP) as shear transverse reinforcement applied in vulnerable reinforced concrete (RC) beams has been proved to be a promising strengthening technique. However, past studies revealed that the effectiveness of this method depends on how well the reinforcement is bonded to the concrete surface. Thus, although the application of EB-FRP wrapping around the perimeter of rectangular cross-sections leads to outstanding results, U-jacketing in shear-critical T-beams seems to undergo premature debonding failures resulting in significant reductions of the predictable strength. In this work, five shear-critical RC beams with T-shaped cross-section were constructed, strengthened and tested in four-point bending. Epoxy bonded carbon FRP (C-FRP) sheets were applied on the three sides and along the entire length of the shear-strengthened T-beams as external transverse reinforcement. Furthermore, the potential enhancement of the C-FRP sheets anchorage using bolted steel laminates has been examined. Test results indicated that although the C-FRP strengthened beams exhibited increased shear capacity, the brittle failure mode was not prevented due to the debonding of the FRP from the concrete surface. Nevertheless, the applied mechanical anchor of the C-FRP sheets delayed the debonding. Moreover, the design provisions of three different code standards (Greek Code of Interventions, Eurocode 8 and ACI Committee 440) concerning the shear capacity of T-shaped RC beams retrofitted with EB-FRP jackets or strips in U-jacketing configuration are investigated. The ability of these code standards to predict safe design estimations is checked against 165 test data from the current experimental project and data available in the literature.

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38

Fanaradelli, Theodora D., and Theodoros C. Rousakis. "3D Finite Element Pseudodynamic Analysis of Deficient RC Rectangular Columns Confined with Fiber Reinforced Polymers under Axial Compression." Polymers 12, no. 11 (October 30, 2020): 2546. http://dx.doi.org/10.3390/polym12112546.

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This paper utilizes the advanced potential of pseudodynamic three-dimensional finite-element modeling to study the axial mechanical behavior of square and rectangular reinforced concrete columns, confined with fiber reinforced polymer (FRP) jackets and continuous composite ropes in seismic applications. The rigorous and versatile Riedel-Hiermaier-Thoma (RHT) material model for concrete is suitably calibrated/modified to reproduce the variable behavior of characteristic retrofitted columns with deficient internal steel reinforcement detailing, suffering nonuniform local concrete cracking and crushing or bulging and bar buckling. Similarly, the 3D FRP jacket or rope confinement models may account for damage distribution, local fracture initiation and different interfacial bonding conditions. The satisfactory accuracy of the reproduced experimental stress-strain envelope behavior enables the analytical investigation of several critical design parameters that are difficult to measure reliably during experiments. Additional parametric analyses are conducted to assess the effects of steel quality. The significant variation of the field of developed strains on the FRP jacket at the ultimate and of the developed strains and deformations on steel cages among different columns are thoroughly investigated. This advanced analytical insight may be directly utilized to address missing critical parameters and allow for more reliable FRP retrofit design of seismic resistant reinforced concrete (RC) columns. Further, it allows for arbitrary 3D seismic analysis of columns (loading, unloading, cyclic or loading rate effects or preloading) or addresses predamages.

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39

Tian, Ying, and Shive K. Chaturvedi. "A Seismic Retrofit Design Methodology for R/C Bridge Columns Using Fiber Composites." Earthquake Spectra 20, no. 2 (May 2004): 483–502. http://dx.doi.org/10.1193/1.1711817.

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Fiber-reinforced polymers (FRP) are attractive materials for seismic upgrading. This paper proposes a design approach for retrofitting reinforced concrete bridge piers with fiber composites in which the nonlinear behavior of the retrofitted column is taken into account. The flexural and shear capacities are investigated and some intuitive conclusions are advanced and utilized in design at the component level. In a multiperformance-based design approach, the capacity spectrum method is utilized to identify the feasibility of using FRP as a retrofit scheme by solving a nonlinear programming problem and then determining the seismic demand. A design example is provided to illustrate the proposed retrofit design procedures.

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40

Abbass, Ammar, Reza Attarnejad, and Mehdi Ghassemieh. "Seismic Assessment of RC Bridge Columns Retrofitted with Near-Surface Mounted Shape Memory Alloy Technique." Materials 13, no. 7 (April 5, 2020): 1701. http://dx.doi.org/10.3390/ma13071701.

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From past earthquakes, it has been found that the large residual displacement of bridges after seismic events could be one of the major causes of instability and serviceability disruption of the bridge. The shape memory alloy bars have the ability to reduce permanent deformations of concrete structures. This paper represents a new approach for retrofitting and seismic rehabilitation of previously designed bridge columns. In this concept, the RC bridge column was divided into three zones. The first zone in the critical region of the column where the plastic hinge is possible to occur was retrofitted with near-surface mounted shape memory alloy technique and wrapped with FRP sheets. The second zone, being above the plastic hinge, was confined with Fiber-Reinforced Polymer (FRP) jacket only, and the rest of the column left without any retrofitting. For this purpose, five types of shape memory alloy bars were used. One rectangular and one circular RC bridge column was selected and retrofitted with this proposed technique. The retrofitted columns were numerically investigated under nonlinear static and lateral cyclic loading using 2D fiber element modeling in OpenSees software. The results were normalized and compared with the as-built column. The results indicated that the relative self-centering capacity of RC bridge piers retrofitted with this new approach was highly greater than that of the as-built column. In addition, enhancements in strength and ductility were observed.

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41

Dai, Kuang-Yu, Xiao-Hui Yu, Kai Qian, and Dai-Yu Wang. "Deformation capacity of FRP retrofitted reinforced concrete columns with corroded reinforcing bars." Engineering Structures 254 (March 2022): 113834. http://dx.doi.org/10.1016/j.engstruct.2021.113834.

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42

Li, Yue, Xiongfei Liu, and Jiaqi Li. "Experimental Study of Retrofitted Cracked Concrete with FRP and Nanomodified Epoxy Resin." Journal of Materials in Civil Engineering 29, no. 5 (May 2017): 04016275. http://dx.doi.org/10.1061/(asce)mt.1943-5533.0001810.

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43

Kalayci, Ahmet Serhat, Baris Yalim, and Amir Mirmiran. "Effect of Untreated Surface Disbonds on Performance of FRP-Retrofitted Concrete Beams." Journal of Composites for Construction 13, no. 6 (December 2009): 476–85. http://dx.doi.org/10.1061/(asce)cc.1943-5614.0000032.

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44

Wu, C., D. J. Oehlers, M. Rebentrost, J. Leach, and A. S. Whittaker. "Blast testing of ultra-high performance fibre and FRP-retrofitted concrete slabs." Engineering Structures 31, no. 9 (September 2009): 2060–69. http://dx.doi.org/10.1016/j.engstruct.2009.03.020.

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45

Guo, Yong Chang, Han Lin Huang, Li Juan Li, Jun Deng, and Gen Quan Zhong. "Effect of Crack on Interfacial Stresses of RC Beam Strengthened with CFRP." Key Engineering Materials 462-463 (January 2011): 559–62. http://dx.doi.org/10.4028/www.scientific.net/kem.462-463.559.

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External bonding of fiber reinforced polymer (FRP) plates or sheets, because of their advantages, such as high strength to weight ratio and good resistance to corrosion, has become a popular technique for the strengthening and upgrading of structurally inadequate or damaged reinforced concrete (RC) structures. Interface debonding failure is one of the most common failure modes of the FRP strengthened RC structures. In this paper, the damaged concrete constitutive model is established and the effects of crack on the interfacial stresses of RC beam strengthened with CFRP are investigated. Longitudinal stress in the CFRP, shear stress in the adhesive layer and the first principal stress in the concrete at the crack tips of the retrofitted RC beams with cracks at different locations are analyzed. The results show that when cracks locate at the loading position, the longitudinal stress in the CFRP is the largest and the tensile failure of the CFRP is the most likely occurred.

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46

Nguyen, Huy Q., Kijae Yang, and Jung J. Kim. "An Efficient Method for Optimizing HPC-FRP Retrofit Systems of Flexural Strengthened One-Way Continuous Slabs Based on ACI 440.2R." Materials 15, no. 23 (November 26, 2022): 8430. http://dx.doi.org/10.3390/ma15238430.

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An innovative retrofit system consisting of fiber-reinforced polymers (FRP) and high-performance concrete (HPC) considering the difficulty of the accessibility and installation of FRP on the underside of reinforced concrete (RC) slabs was found to be efficient in the flexural strengthening of existing RC slabs. It is important to note that continuous slabs using the FRP-HPC retrofit systems are less effective in exploiting FRP tensile strength and can cause sudden failure once excessively enhanced flexural strength exceeds shear strength. A design method to ensure ductile failure mode was also proposed for strengthened continuous RC slabs in the previous literature. Thus, it is necessary to optimize retrofit systems in terms of mechanical performance aspects to improve the efficiency of retrofitted slabs in serviceability. This study proposes a design method for optimizing the strength of materials and inducing ductile failure of continuous slab retrofitting FRP-HPC systems. The proposed approach demonstrated its effectiveness for strengthening a continuous RC slab with various FRP-HPC retrofit systems through a case study. The results show that the design factored load in the serviceability limit state does not change appreciably from a decrease in carbon fiber-reinforced polymers (CFRP) of 38%; the design factored load decreased only by 9% and the ultimate failure load by 13% while reducing CFRP by 20% and HPC by 25%.

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Hojatkashani, Ata, and Mohammad Zaman Kabir. "Innovative experimental and finite element assessments of the performance of CFRP-retrofitted RC beams under fatigue loading." Science and Engineering of Composite Materials 25, no. 4 (July 26, 2018): 661–78. http://dx.doi.org/10.1515/secm-2016-0101.

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Abstract Numerous experimental studies have proven the efficiency of externally bonded fiber-reinforced polymer (FRP) systems on structural concrete elements, such as reinforced concrete (RC) beams. The current paper presents an analytical formulation of mechanical constants based on the results of experimental data, which were acquired from fatigue testing of intact and CFRP-retrofitted RC beams. A total of six scaled RC beams were prepared for the test, three of which were strengthened with carbon fiber-reinforced polymers (CFRPs). A specific finite element model coupled with experimental results from the proposed RC beams made it possible to compare the theoretical and experimental fatigue behavior of RC beams with and without composite reinforcement. The developed numerical model was then extended to evaluate a higher number of fatigue load cycles, as recommended by bridge codes. This was carried out to monitor the performance of CFRP-retrofitted RC beams in terms of flexural stiffness deterioration and damage propagation. The relationships presented in this paper were calibrated to the tested specimens. Moreover, they were useful for the design of RC and CFRP-retrofitted RC beams and for predicting fatigue performance, including the damage behavior of constituent materials.

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Mourão, R., A. Maazoun, F. Teixeira-Dias, J. Vantomme, and D. Lecompte. "Load-Displacement Assessment of One-Way Reinforced Concrete (RC) Slabs Externally Strengthened Using CFRP Strips under Blast Loads." Proceedings 2, no. 8 (July 12, 2018): 541. http://dx.doi.org/10.3390/icem18-05435.

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Dynamic behaviour of Reinforced Concrete (RC) structures can be assessed using a Single-Degree-of-Freedom (SDOF) approach. Such a method is highly dependent on the resistance curve of the structure which is generally represented by a bilinear elasto-perfectly-plastic approximation. This approximation might lead to erroneous results when it refers to the use of externally bonded Fibre Reinforced composites for flexural capacity upgrade of Reinforced Concrete (RC), mainly when the concrete-to-FRP interface failure is to be included. One-way slabs are experimentally and numerically investigated in this study in a 3-point flexural configuration. Assessment on the load-displacement behaviour of a reference specimen and its retrofitted counterpart is performed. Special attention is given to the behaviour of the structure after the concrete-to-FRP failure. Comparison is made between experimental and numerical results and a good agreement is obtained. A complementary analytical study based on the SDOF method is conducted to understand the influence of several resistance curves on the overall displacement of the same structure when subjected to different pressure-impulse combinations.

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Irandegani, Mohammad Ali, Daxu Zhang, Mahdi Shadabfar, Denise-Penelope Kontoni, and Mudassir Iqbal. "Failure Modes of RC Structural Elements and Masonry Members Retrofitted with Fabric-Reinforced Cementitious Matrix (FRCM) System: A Review." Buildings 12, no. 5 (May 13, 2022): 653. http://dx.doi.org/10.3390/buildings12050653.

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Much research has been conducted and published on the examination of the behavior of reinforced steel and concrete structures with a FRP system. Nevertheless, the performance of FRP differs from that of FRCM, particularly at high temperature and ultimate strength. The present study provides a review of previous research on structural elements (viz. beams, columns, arches, slabs, and walls) retrofitted with FRCM systems, taking account of various parameters, such as layers, composite types, configurations, and anchors for controlling or delaying failure modes (FMs). Additionally, this paper discussed the details of different FMs observed during experimental tests, such as crushed concrete or bricks, fiber debonding from substrate materials, slippage, fiber rupture, and telescopic failure for strengthened specimens. Moreover, this paper investigated where and how fractures may develop in structural elements retrofitted with the FRCM system under various retrofit scenarios. To this end, in addition to the review of the relevant literature, a large dataset has been compiled from different (RC) structural elements and masonry members. Next, a relationship is developed between failure modes (FMS) and influential parameters, i.e., the number of layers and the type of composite, based on this dataset. This can be used as a benchmark example in future studies, as there is no such basis available in the literature, to the best of the authors’ knowledge.

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Abbas, Husain, S. M. Ibrahim, Naif Al-Hazmi, Hussein Elsanadedy, Tarek Almusallam, and Yousef Al-Salloum. "Axial Compression Behavior of Wall-Like Reinforced Concrete Columns Retrofitted Using Different FRP Schemes." Buildings 13, no. 1 (December 22, 2022): 26. http://dx.doi.org/10.3390/buildings13010026.

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Experimental and numerical investigations on the retrofitting of half-scale wall-like reinforced concrete (RC) columns were conducted. The axial compressive behavior of the control un-strengthened wall-like RC column (having a section aspect ratio of four) was compared with the strengthened columns. The columns were strengthened by employing external confinement through fiber-reinforced polymer (FRP) wraps and/or steel/FRP strips with/without modification of the column cross-section. The characteristics of axial load versus displacement and strain curves were discussed. The experimental results were also compared with the numerical models, which were first validated against the previous studies. A reasonably close agreement was achieved between the numerical and the test results with an error in prediction of less than 10% for the peak load. With the different schemes used for confinement, the enhancement in the load capacity of strengthened columns was in the range of 30–42% of the control column. In addition, significant ductility improvements were seen in schemes that employed the FRP wraps after shape modification.

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Journal articles on the topic 'FRP-retrofitted concrete'

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