Diagnostic Load Test of a Scaled Post-Tensioned Flat Plate Concrete Slab

A flat plate floor system is a concrete system that has uniform thickness. They are generally cast-in-place or they may be casted at the ground level and lifted into their final position by the use of jacks at the columns. This system can be post-tensioned. Flat plate post tensioned concrete slabs are widely used in office buildings, institutional structures, parking structures, apartment buildings, and hotels. Therefore, it is important to have a good understanding of the behavior of these elements that form the fabric of the total structural system. The main goal of this work was to perform a design evaluation on a constructed scaled post-tensioned 4 ft x 4 ft flat plate concrete slab with American Concrete Institute (ACI) design provisions. The 28 days compressive strength of concrete was 5000 psi. The slab thickness was 1/2 in, and 1/16 in post-tensioning cables inside a plastic sheathing were used as the reinforcement. The slab was loaded using a designed water tank of 4 ft x 4 ft x 6 ft dimensions. The water depth generated the distributed load on the slab and a dial gauge measured the slab deflections. Distributed load and deflection data were collected. The design evaluations were carried out with respect to deflections, stresses, shear and flexural capacity using a developed ACI provisioned spreadsheet and experimentally obtained load and deflection data. The scaled constructed concrete slab satisfied the ACI design provisions.