A Master of Science thesis in Civil Engineering by Raed Abokwiek entitled, "Strengthening of Reinforced Concrete Columns Using Composite of Near Surface Mounted CFRP Strips and Fabric," submitted in January 2016. Thesis advisor is Dr. Jamal A. Abdalla, thesis co-advisors are Dr. Rami A. Hawileh and Dr. Tamer El Maaddawy. Soft and hard copy available.
In this study, the efficiency of using near surface mounted (NSM) carbon fiber reinforced polymer (CFRP) strips with CFRP confinement for strengthening reinforced concrete (RC) columns was investigated. The columns were subjected to concentric load and eccentric load which resulted in uniaxial and biaxial bending. Twenty seven specimens of RC columns with different reinforcement ratios were used. The specimens were divided into three groups; Axial, Uniaxial and Biaxial groups. Each group was subdivided into multiple subgroups with a control un-strengthened specimen. Experimental testing was carried out in order to study the effect of using NSM CFRP strips reinforcement on short columns considering the effect of several parameters. Likewise, the determination of the efficient increase in capacity of the RC columns by varying the number of CFRP strips to be used as reinforcement was studied. Moreover, a comparison was carried out between the efficiency of using NSM CFRP reinforcement with CFRP confinement and without the confinement. Besides, examination of the correlation between the loading pattern, load eccentricity and the effect of NSM CFRP strip on the column capacity was examined. Furthermore, the columns were well instrumented to measure lateral deflection, axial deflection and longitudinal and transverse strains. Failure modes, load-deflections and load-strains relationships were investigated. The strengthened specimens showed a significant increase in the load-carrying capacity and ductility over the control specimens. The increase in the load-carrying capacity for confined columns strengthened with strips in axial, uniaxial and biaxial bending ranged from 36 to 49%, 48 to 95% and 76 to 128%, respectively. The results showed that strengthening RC columns with NSM CFRP composites enhances the capacity and ductility consistently with respect to certain applied eccentricity ratio. In addition, an analytical model to predict the structural behavior of the NSM CFRP strengthened RC columns was developed and presented in this thesis showing fair agreement with the experimental results with deviations ranging from 1 to 18%. Finally, validation of the experimental results against the developed model was done in order to perform future parametric studies and to gain complete understanding of each parameter effect, separately.