Retrofit of Concrete Slabs with FRP to Resist Progressive Collapse

The application of Fiber Reinforced Polymer (FRP) strips as Tie Elements in strengthening of existing concrete slabs to resist progressive collapse is investigated. In the Tie Force approach it is essential that the FRP strips, designed to behave as Tie Elements, possess the deformation capacity required for large deflections to develop catenary action. The Tie Force approach and the behavior of FRP strips acting as Tie Elements are discussed. The properties of Carbon Fiber Reinforced Polymers (CFRP) and Glass Fiber Reinforced Polymers (GFRP) are compared and it is concluded that the GFRP is more adequate as Tie Element to fulfill the requirement of slabs to undergo a rotation of 0.2 rad. In order to transfer the gravity loads away from the damaged area, an application of Fiber Anchors is introduced to properly connect the concrete slab to the strips. The FRP strips and the FRP anchors from a current retrofit project will be presented.