Strengthening of Prestressed Concrete Hollow-Core Slab Openings Using Near-Surface-Mounted Carbonfiber- Reinforced Polymer Reinforcement

The effect of openings on the behavior of prestressed concrete hollow-core slabs and the efficiency of near-surface-mounted reinforcement as a strengthening technique are investigated. Five full-scale prestressed concrete hollow-core slabs were tested: one with no opening, two with openings in different locations, and two with identical openings strengthened with near-surface-mounted carbon-fiber-reinforced polymer (CFRP) strips. The slabs were tested in four-point bending. The openings were cut either in the pure flexural span or in the shear span. Test results showed that the presence of an opening along the flexure span or the shear span significantly decreased the postcracking flexural stiffness and capacity of the slab. In addition, strengthening openings with near-surface-mounted CFRP strips effectively enhanced the postcracking stiffness, increased the ductility of the member, restored the flexural strength deficit incurred as a result of cutting the openings, and provided a net increase in flexural capacity.