Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 95-99). Also available on the World Wide Web.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 148-162). Also available in electronic version.

Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

Thesis (M. Phil.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

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.

Submitted as the dissertation component in partial fulfillment of the requirements for the Masters Diploma in Technology (Electrical engineering - heavy current), Electrical Engineering, ML Sultan Technikon, 1998. / The use of pre-stressed concrete poles for the Inwabi Plateau rural distribution line has presented unforseen problems for the Durban Electricity Service Unit, such as poor line performance and structural damage to the poles. The effects are thought to be due to lightning. This dissertation deals with an investigation into the cause of the damage as well as recommendations regarding the repair and prevention of future damage. To achieve this, an evaluation of the line Basic Insulation Level (B.I.L.) together with a review of the existing literature on the effects of lightning to overhead lines was used in order to establish what the specific damage mechanisms are. Field and laboratory tests were also undertaken as part of the investigation. Based on the results obtained, the overhead line was modified in terms of it's B.I.L. A preliminary evaluation of the modifications was done, with recommendations regarding further work to be done in the future. / M

This investigation represents a comparative study of the flexural behavior of lightweight and normal weight concrete. Both theoretical and experimental moment-curvature characteristics of the tested specimens were used to study the flexural behavior. A generalized computer program to determine the moment-curvature relationships of a singly reinforced rectangular concrete beam was developed. For this limited study it was observed that lightweight concrete beams when compared to normal concrete beams achieve comparable moment capacity (about 92% of normal weight concrete) but exhibit higher deflections (about 40% more than normal weight concrete).

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Methods are presented for the predication of the short-term and sustained load behaviour of reinforced concrete frames. These procedures are evaluated by an experimental program using a particular structure and loading configuration. The results of two short-term tests and one sustained load test are compared with the analytic predictions. The inadequacy of classical methods of structural analysis for sustained load problems is also discussed. It is concluded that the methods using small elements, numerical integration and successive iterations can provide accurate predictions of short-term and sustained load behaviour of reinforced concrete beams. / Thesis / Master of Engineering (ME)