An analytical procedure to determine the need for concrete confinement at the boundaries of the RC structural walls subjected to earthquake load is presented by relating the displacement demand of the building system to the local deformation in the wall cross section. The primary variables used to determine the need for confinement are the ratio of wall cross sectional area, the wall axial load and the wall reinforcement ratio. The validity of the analytical approach is demonstrated by evaluating two existing buildings in Bangladesh and also by comparison with the experimental study of a two-third scale shear wall conducted in this study. The proposed approach can be used for evaluation of existing shear wall buildings as well as to verify current force-based procedure to determine the need for confinement of shear wall in Bangladesh.
Parallel to the evaluation of need for confinement at the boundaries of shear wall, experimental study has also been performed to evaluate the effectiveness of using externally bonded carbon fiber sheet (CFS) to increase the confinement of boundary elements of RC shear wall. The experimental program comprises three two-third scale wall panels representing the control wall and two CFS-retrofitted wall panel using two different retrofit schemes. Based on the procedure in ACI 440.2R-08 for strengthening RC structures by externally bonded FRP systems, an analytical procedure for retrofit design of shear wall to improve ductility, has been presented and verified by the experimental results.