In some cases, openings must be introduced after slab construction to accommodate ducts, pipes, utilities, and elevators. This study involves the development of three-dimensional, complex, nonlinear finite elementanalysis (FEA) models of precast concrete slabs with and without openings. One solid precast concrete slab and five slabs with various opening shapes but equal areas were considered. The openings in the slabs were retrofitted with carbon-fiber-reinforced polymer (CFRP) sheets around their perimeters to restore the original flexural strength and stiffness of the floors. Rectangular, circular, square, elliptical, diamond-shaped openings were investigated for the control specimens and the corresponding CFRP-strengthened slab models. An experimental study on a reinforced concrete solid slab and as-built and CFRP-strength-ened slabs with rectangular openings reported in the literature was used to validate the accuracy of the proposed FEA models. The FEA results revealed that the slabs with rectangular and elliptical openings outperformed the slabs with other opening shapes in terms of stiffness and ultimate-flexural-strength capacity. CFRP strengthening enhanced the performance of all of the slabs with openings compared with their corresponding control models. Through CFRP reinforcement, the losses in stiffness and flexural strength caused by the cutouts were restored. In the case of the slab with rectangular openings, similar flexural strength and increased stiffness were attained compared with the slab without any opening.
