Modeling of Reinforced Concrete Slabs Strengthened with Fiber-Reinforced Polymer or Steel Plates

This research aims to create precise finite element models for strengthened two-way slab-column connections. The connections are categorized according to the strengthening type as flexural or punching shear specimens. Two different strengthening techniques are modeled using steel plates or fiber-reinforced polymer (FRP) strips or laminates. FRP-strengthened connections are subjected to central axial loads. The connections that use an assembly of steel plates and bolts are subjected to a central load or a combination of central load and moment. The three-dimensional (3D) assembly of the slab and column of the connections is simulated. In addition, the interfacial behavior between the FRP materials and concrete is taken into account. Furthermore, a user-defined subroutine for the microplane model for concrete is incorporated in the finite element package. Results are presented in terms of the ultimate load capacities, load-slip relationships, load-interfacial stress relationships, and stress distributions in the strengthening materials.