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1	Cyclic and Impact Resistance of FRP Repaired Poles Mohsin, Zainab 01 January 2015 (has links) Sign and signal structures involved in vehicular accidents are often partially damaged, and it is possible to repair them instead of replacing them, even when the extent and severity of the damage are substantial. The replacement of these poles is costly and involves interruption for pedestrians and traffic. Therefore, some trials were performed to retrofit these poles in-situ with low cost and short time. Previous research has substantiated that the damage can decrease the strength of the these structures with increasing the dent depth and the use of externally-bonded fiber-reinforced polymer (FRP) composites are beneficial to repair them. The composite systems were comprised of glass or basalt fibers paired with epoxy or polyurethane matrices. The effectiveness of FRP in repairing the damaged poles was demonstrated in previous tests on dented poles using 3-point, 4-point, and cantilever bending tests. The repair systems were able to develop the load carrying capacity of the damaged poles, and their behaviors were controlled by various types of failure modes like yielding of the metallic substrate, FRP tensile rupture, FRP compressive buckling, and debonding of FRP from the substrate. This thesis investigates the resistance of repaired full-scale metallic poles retrieved from the field for monotonic, cyclic, and impact loading. These poles, which have rounded and multi-sided cross sections with and without access ports, were dented in the field or dented mechanically in the laboratory and repaired with the same repair systems mentioned previously. Six of these poles were mounted horizontally in a cantilever configuration to test them monotonically, while three of them were tested cyclically. In both tests, the load was applied as a point load at 9 ft from the base plate. Additionally, two poles were mounted vertically using a cantilever configuration to test them for impact. This test was performed by hitting the poles using an impact pendulum with a 1100 kg mass.The results of static tests show that the repair systems failed because of the aforementioned failure modes. However, most of the failure was located outside the dented region, which indicates the effectiveness of these repair systems in restoring the capacity of the damaged area. During the fatigue tests, the repair experienced no damage before weld rupture in the original steel tube-base plate connection. Moreover, the repair systems proved their effectiveness in resisting the impact load, because they were ruptured at the contact region between the pole and the impactor at the time the poles were deformed at the free side of the poles, as well as the impact side, during the test. In all these tests, the access ports affected the behavior of the repaired poles. Depending on the geometry of the pole, metal substrate, and dent depth and location, FRP repair system recommendations will be presented. Frp repaired poles Engineering
2	Impact behaviour of reinforced concrete beams strengthened or repaired with carbon fibre reinforced polymer (CFRP) Al-Farttoosi, Mahdi January 2016 (has links) War, terrorist attacks, explosions, progressive collapse and other unforeseen circumstances have damaged many structures, including buildings and bridges in war- torn countries such as Iraq. Most of the damaged structural members, for example, beams, columns and slabs, have not totally collapsed and can be repaired. Nowadays, carbon fibre reinforced polymer (CFRP) is widely used in strengthening and retrofitting structural members. CFRP can restore the load- carrying capacity of damaged structural members to make them serviceable. The effect of using CFRP to repair the damaged beams has not been not properly addressed in the literature. This research has the aim of providing a better understanding of the behaviour of reinforced concrete beams strengthened or repaired with CFRP strip under impact loading. Experimental and analytical work were conducted in this research to investigate the performance of RC beams strengthened or repaired using CFRP. To study the impact behaviour of the CFRP reinforced concrete beams, a new heavy drop weight impact test machine has been designed and manufactured to conduct the experimental work. Twelve RC beams were tested experimentally under impact load. The experimental work was divided into two stages; stage 1 (strengthened) and stage 2 (repair). At stage 1, three pairs of beams were tested under impact loading. External bonded reinforcement (EBR) and near surface mounted (NSM) techniques were used to strengthen the RC beams to find the most effective technique. Three pairs of beams were tested in stage 2 (repair). Different degrees of damages were induced using different impact energies. NSM technique was used to repair the damaged beams using CFRP strip. Stiffness degradation method was used to assess the degree of damage in beams due to impact. The study investigated the stiffness, bending load, impact energy, deflection and mode of failure of CFRP strengthened or repaired beams under impact loading. The distribution of the stresses, strains, accelerations, inertia forces, and cracks in the beam under impact loading was also investigated in this study. Empirical equations were proposed in this research to predict the bending load and maximum deflection of the damaged and repaired beams under impact loading. For validation purposes, finite element analysis was used with the LUSAS package. The FEA results were compared with the experimental load-deflection curves and ultimate failure load results. In this research, to simulate a real situation, different models were used to simulate the bonding between the CFRP and concrete and also between steel bars and concrete. In these FEA models, the bonding between the concrete and the CFRP was modelled using the Drucker-Prager model. To simulate the bonding between steel and concrete, a joint element was used with spring constants to model the bond between steel bars and surrounding concrete. The analytical results were compared with the experimental results. In most previous research, FEA has been used to simulate the RC beams under impact loading without any damage. In this thesis, a new 3D FEA model was proposed to simulate and analyse the damaged RC beams under impact loading with different degrees of damage. The effect of the damage on concrete stiffness and the bonding between the steel bars and the concrete were investigated in FEA model. The damage was modelled by reducing the mechanical properties of the concrete and the bonding between steel bars and concrete. This thesis has contributed to improving knowledge of the behaviour of damaged beams repaired with CFRP, and the experimental work conducted, together with the numerical analysis, have provided essential data in the process of preparing a universal standard of CFRP design and construction. In the FEA model, the damage to the beams due to impact loading was successfully modelled by reducing the beam stiffness. 620.1
3	Bond strength of the interface between concrete substrate and overlay concrete containing fly ash exposed to high temperature Behforouz, B., Tavakoli, D., Gharghani, M., Ahsraf, Ashour F. 25 October 2022 (has links) Yes / Bond between substrate and overlay concretes is a key factor for the success of the repair method and significantly influences the structural performance of the repaired element. This study investigated the effect of fly ash and the surface preparation method on the bond strength of repaired concrete after exposure to high temperatures, that has not been comprehensively studied in the literature. For this purpose, overlay concretes containing 0, 5, 10, 15, and 20% fly ash as a replacement by weight of cement were cast on the original concrete surface prepared by four methods namely, as-cast, wire brushed, grooved and grooved-wire brushed. The bond strength of the interface between concrete substrate and overlay concrete was evaluated after exposure to 23, 200, 400, and 600oC temperatures for 1 hour. The results showed that partial replacement of cement by fly ash in the overlay concrete increased the bond strength of repaired concrete by up to 71%, depending on the amount of fly ash used, surface preparation method, and the temperature to which the sample was exposed. The maximum increase of bond strength was recorded for concrete containing 20% fly ash when the wire brushed preparation method was adopted at temperature of 200oC. However, surface preparation was the most influential parameter, achieving a bond strength gradual increase in order from as-cast, wire brushed, grooved to grooved-wire brushed methods. The results also showed that for most of the samples having similar surface preparation and the same percentage of fly ash, bond strength decreased with the increase of exposure to temperature; for example, for overlay concretes without fly ash, in as-cast and wire brushed surface preparation methods at temperatures of 400 and 600 oC, the bond strength has reached zero. On the other hand, for grooved and grooved-wire brushed surface preparation methods, the bond strength reduction was about 63%, when temperature increased from 23 to 600oC. / The full-text of this article will be released for public view at the end of the publisher embargo, 12 month from first publication. Bond strength Fly ash High temperature Repaired concrete Substrate
4	A vítima no processo penal e a reparação do dano pelo juízo criminal Lopes Junior, Vianey Mreis 17 October 2012 (has links) Made available in DSpace on 2016-04-26T20:21:17Z (GMT). No. of bitstreams: 1 Vianey Mreis Lopes Junior.pdf: 327076 bytes, checksum: 06ef2cf33fc3f1ef76da6f643d9f461d (MD5) Previous issue date: 2012-10-17 / The present paper intends to demonstrate the victim´s historical position in the penal process and their evolution as a character in the penal process, starting at the time of their greatest protagonism, with the revenge, up to their present situation at the time of the State´s monopoly, where the victim must be supported by the State and compensated by the delinquent for the crime. We intend to demonstrate that the victim, under the protection of the Rule of Law and the Principle of the Dignity of the Human Being, which are eternity clauses in the federal Constitution of 1988 and guiding lines of this study, in face of the moral and material damages suffered as a result of the crime needs to have those damages, both moral and material, repaired, the delinquent being required to do so as well as the State, which must provide the conditions for their total rehabilitation. The study of the legislative reform introduced by Law 11.719/2008, interpreted under the constitutional realm, supported by principles and jurisprudence, still incipient, proves those aspects with their clear re-valuation, in this context. Furthermore, we point out the need for extensive action by the Criminal Court, which had added to its scope of actions the ascertainment of the defendant´s responsibility as related to the victim´s damages, with no offense to the already accomplished constitutional principles of the penal process, and the need for the consequent determination of an effective compensation so that the victim´s claims can be satisfied, so that the international treaties can be validated, and so that the civil court can be released of the extra burden of unnecessary filing for new requests of compensation / O presente trabalho analisa a posição da vítima ao longo da história, ora como principal protagonista do processo, ora afastada e substituída pelo Estado Juiz. A Constituição Federal de 1988, ao eleger o Estado Democrático de Direito sob a luz do Princípio da Dignidade Humana após estabelecer inúmeras garantias, revalorizou a vítima da criminalidade violenta, trazendo explicitamente a obrigação de amparo e assistência. A vítima foi revalorizada por extensa legislação ordinária posterior à Constituição e finalmente com a Lei 11.719/2008 de 11/06 de 2008 que tratou de sua indenização em sede do Juízo Criminal, na busca por reparação de danos sofridos em virtude do crime. A reparação agora determinada pelo Juízo Criminal com evidente intenção de celeridade e eficiência, aferindo o dano e estipulando a indenização, com evidente alargamento de sua competência. Neste diapasão ainda estuda-se a forte corrente que gradativamente propõe ser o Estado concorrente e solidário na responsabilidade pela reparação dos danos decorrentes dos danos sofridos pela vítima oriundos da criminalidade violenta Vítima Reparação do dano Juízo criminal Estado democrático de direito Princípio da dignidade humana Victim Rule of law Principle of the dignity of the human Repaired
5	Rehabilitation of Exterior RC Beam-Column Joints using Web-Bonded FRP Sheets Mahini, Seyed Saeid Unknown Date (has links) In a Reinforced Concrete (RC) building subjected to lateral loads such as earthquake and wind pressure, the beam to column joints constitute one of the critical regions, especially the exterior ones, and they must be designed and detailed to dissipate large amounts of energy without a significant loss of, strength, stiffness and ductility. This would be achieved when the beam-column joints are designed in such a way that the plastic hinges form at a distance away from the column face and the joint region remain elastic. In existing frames, an easy and practical way to implement this behaviour following the accepted design philosophy of the strong-column weak-beam concept is the use a Fibre Reinforced Plastic (FRP) retrofitting system. In the case of damaged buildings, this can be achieved through a FRP repairing system. In the experimental part of this study, seven scaled down exterior subassemblies were tested under monotonic or cyclic loads. All specimens were designed following the strong-column weak-beam principal. The three categories selected for this investigation included the FRP-repaired and FRP-retrofitted specimens under monotonic loads and FRP-retrofitted specimen under cyclic loads. All repairing/retrofitting was performed using a new technique called a web-bonded FRP system, which was developed for the first time in the current study. On the basis of test results, it was concluded that the FRP repairing/retrofitting system can restore/upgrade the integrity of the joint, keeping/upgrading its strength, stiffness and ductility, and shifting the plastic hinges from the column face toward the beam in such a way that the joint remains elastic. In the analytical part of this study, a closed-form solution was developed in order to predict the physical behaviour of the repaired/retrofitted specimens. Firstly, an analytical model was developed to calculate the ultimate moment capacity of the web-bonded FRP sections considering two failure modes, FRP rupture and tension failure, followed by an extended formulation for estimating the beam-tip displacement. Based on the analytical model and the extended formulation, failure mechanisms of the test specimens were implemented into a computer program to facilitate the calculations. All seven subassemblies were analysed using this program, and the results were found to be in good agreement with those obtained from experimental study. Design curves were also developed to be used by practicing engineers. In the numerical part of this study, all specimens were analysed by a nonlinear finite element method using ANSYS software. Numerical analysis was performed for three purposes: to calculate the first yield load of the specimens in order to manage the tests; to investigate the ability of the web-bonded FRP system to relocate the plastic hinge from the column face toward the beam; and to calibrate and confirm the results obtained from the experiments. It was concluded that numerical analysis using ANSYS could be considered as a practical tool in the design of the web-bonded FRP beam-column joints. Reinforced concrete Reinforcement Bar strong-column weak-beam principal Exterior Beam-Column Joints Core Small scale modelling Experimental Test set-up Control Plain specimen Rehabilitation Retrofitting retrofitted Repair Repaired Repairing Strengthening Controlling Relocating Plastic hinge Pre-cracking Cracking Crushing Post-cracking Crack Cracked Penetration Damaged Pre-cracked Web-Bonded Wrapping De-bonding Fibre Reinforced Plastic FRP Sheets Composite Confinement Monotonic loads Cyclic loading Loads Displacement control Load control Regime Phase Loading sequence Procedure Available ductility factor Curvature ductility factor Ultimate First yield Flexural yielding Strength Moment Stiffness Failure mechanism Modes Sudden Brittle failure Measured beam-tip displacement Deflection Numerical analysis ANSYS Solid65 Solid45 Link8 Non-linear Finite Element (FE) Convergence criteria Analytical Closed from FRP rupture tension failure Compression failure Minimum thickness Maximum thickness Compressive Tensile Steel Ratio Design charts Effective Moment of Inertia Compatibility Strain Stress

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