Seismic Performance Of Rc Shear Walls With Openings Strengthened With Advanced Composites

Over the past few years or so, retrofitting of existing buildings, rather than new construction, became more popular due to economic reasons and the benefit of shorter service interruptions of constructed facilities. Remodeling of existing structures may require removal of portions of the structural members such as introducing door and window openings in an existing shear wall. In these scenarios, a remedial retrofitting is needed to restore the structural integrity and the seismic ductility of the building. This study focuses on developing, validating and modeling of innovative retrofit composite system for reinforced concrete (RC) shear walls with and without openings. The research comprised of two major interrelated parts; (i) Theoretical and numerical modeling, and (ii) Large-scale experimental verification. Specifically, the following tasks were accomplished: (i) Large-scale experimental evaluation of wall specimens with and without retrofit with different opening geometry, (ii) Design and development of external FRP composite retrofit techniques for RC shear walls with openings, (iii) Development and validation of finite element (FE) models capable of predicting the behavior of both the as-built and retrofitted wall specimens, and (iv) Providing research conclusions and recommendations for future research. The experimental results obtained from this study indicated that the proposed carbon/epoxy FRP (CFRP) strengthening systems for RC shear walls with openings were successful in significantly enhancing both the strength and ductility of the retrofitted walls. The average strength gain and ductility enhancement of the retrofitted walls, as compared to the "as-built" walls ranged from 28% and 20%, respectively. The non-linear FE models were successful in simulating the capacities of the wall specimens with an accuracy ranging from 78% to 99%. In addition, the results obtained from the simplified analytical procedures developed in this study were found to be satisfactory in designing such retrofitted walls. It is anticipated that the results of this pioneering study will provide structural engineers with an alternative innovative retrofitting techniques offering flexibility, and economic benefits for enhancing structural behavior of RC shear walls with openings. The results of this study will form basis for establishing a new design procedures that can the basis for building codes in USA.