Concrete walls with cutout openings strengthened by FRP confinement

Abstract

Redesigning buildings to improve their space efficiency and allow changes in use is often essential during their service lives to comply with shifts in living standards and functional demands. This may require the introduction of new openings in elements such as beams,walls, and slabs, which inevitably reduces their structural performance and hence requires repair or strengthening. However, there are uncertainties regarding both the effects of openings and the best remedial options for them. Here, the authors report on an experimental investigation of the effectiveness of fiber-reinforced polymer (FRP)–based strengthening for restoring the axial capacity of a solid RC wall after cutting openings. Nine half-scale specimens, designed to represent typical wall panels in residential buildings with and without door-type openings, were tested to failure. It was found that FRP-confinement and mechanical anchorages increased the axial capacity of walls with small and large openings (which had 25 and 50% reductions in cross-sectional area, respectively) by 34–50% and 13–27%, to 85–94.8% and 56.5–63.4% of their precutting capacity, respectively.