A mixed finite element model for FRP-strengthened RC slabs based on sequential linear analysis

The aim of the present study is to develop a quasi-3D finite element model for predicting the nonlinear behavior of reinforced concrete (RC) slabs strengthened with fiber-reinforced polymers (FRP). The equivalent layered concept is adopted for modelling the constituent parts of the slab, including steel reinforcements, FRP sheets, concrete, and adhesive layers. The kinematical relation of the FRP-strengthened RC slab is approximated by using a mixed stress-displacement field plate theory. Material nonlinearity of the slab's constituents is included in the formulation. To overcome the convergence problems that traditional nonlinear algorithms are usually encountered with them, the sequential linear analysis approach is employed for simulating the crack propagation process. To evaluate the accuracy, numerical results obtained from the presented sequential linear FE model are compared with other similar numerical and experimental results available in the literature. The comparisons show that the proposed formulation is a simple and efficient tool for predicting the nonlinear behavior of FRPstrengthened RC slabs.