Saudi Cultural Missions Theses & Dissertations
Permanent URI for this communityhttps://drepo.sdl.edu.sa/handle/20.500.14154/10
Browse
2 results
Search Results
Item Embargo Structural behaviour of FRP strengthened reinforced concrete members subjected to axial compression and lateral impact loading(The University of Manchester, 2024) Almatrafi, Abdulrahman; Cunningham, LeeStructural members are designed to different types of loadings which ideally designed to withstand them. Structural members can be vulnerable to impact load generated from different sources such as vehicle collision, falling debris or impact risk that appears post-construction. Fibre Reinforced Polymer (FRP) proved to be effective to increase the capacity of different structural members under static loading and is also commercially available, lightweight and practical for external installation. Therefore, assessing the effectiveness of using FRP to strengthen existing axially loaded reinforced concrete (RC) members against impact loading is the primary focus of this research. This work investigates the dynamic behaviour of CFRP strengthened axially loaded RC members subjected to impact loading using experiment and extensive numerical modelling. To achieve this aim, a series of experiments were conducted including impacting un-strengthened and strengthened members under different impact energies, pre-axial loading levels and CFRP configurations. To further expand the understanding of the dynamic behaviour, a numerical model was developed using ABAQUS CAE and validated against the experimental results and related published experiments followed by a parametric study of different variables such as wrapping region, sheet thickness and impact location. Lastly, a full-scale sized column under a typical impact event was then undertaken to apply this understanding to real-life applications. The results show the ability of CFRP to effectively resist impact load in terms of load, deflection, strains, local and global damage. Although a fully wrapped configuration reduced lateral displacement by 30%, a discrete banding configuration achieved comparable performance while saving around 40% of the CFRP material. Axial loading levels of >5%, 25% and 50% positively affect limiting damage and reducing lateral displacement at higher loading levels. The results suggest that CFRP can effectively prevent concrete column failure up to a 40 km/h impact velocity, though limitations emerge beyond this threshold.38 0Item Restricted Behavior of Reinforced Concrete Beams Strengthened with Anchored FRP Sheets under Cyclic Load Reversals(Kansas State University, 2024-07-23) Alshamrani, Salman; Rasheed, HayderThe use of carbon fiber reinforced polymer (CFRP) composites is a widely accepted method for externally strengthening reinforced concrete members. However, there is a notable gap in the literature regarding the behavior of CFRP-strengthened beams fiber anchors under reversed cyclic loading. This study addresses this gap by examining the performance of normal and low-strength concrete, with a moderate steel ratio (0.005) and low steel ratio (0.0034), in constructing fourteen identical full-scale rectangular beams. These beams were strengthened with both unanchored and anchored CFRP sheets. Based on the concrete strength, steel ratio, and CFRP scheme, the beams were categorized into three groups. The first group comprised five beams with lightly reinforced steel and low-strength concrete. This group included a control specimen, as well as strengthened specimens with thin sheets with and without fiber anchors and strengthened specimens with thick sheets with and without fiber anchors. The second group replicated the first group in terms of CFRP scheme, but with a moderate steel ratio and higher-strength concrete. The third group consisted of four beams, two with the same lightly reinforced steel and low-strength concrete as those of group 1, and two with the same moderate steel ratio and higher-strength concrete as those of group 2. This third group consisted of two beams strengthened with double thick CFRP sheets top and bottom secured with fiber anchors. The other two were strengthened using a recent patent concept suggesting the use of a small steel plate as a ductility fuse by sandwiching it in between two layers of FRP at the critical plastic hinge region. All specimens underwent cyclic testing under displacement control, following the AC 125 loading protocol (Acceptance Criterion 125, ICC). The failure modes varied among all three groups, including excessive yielding, CFRP sheet debonding, CFRP sheet rupture, shear failure, and cover delamination. The hysteresis response loops of the different specimens were compared, including ultimate capacity, ductility, stiffness degradation, and energy dissipation. Furthermore, this study involved the development of a phenomenological model to predict the response behavior of RC beams subjected to fully reversed loading cycles until failure. The comparative discussion and analysis of the results with the phenomenological model exhibited a promising correspondence. Finally, experimental observations were conducted to investigate the behavior of the structural systems with the indicated innovative materials under reverse cyclic loading, as well as the load-deflection, and the moment-curvature response. These observations aim to establish a basis for future analytical modeling of the hysteresis response of RC beams strengthened with CFRP sheets with and without fiber anchors.14 0