A Simple Decision Tool to Ensure the Safety of Coastal Home Elevation Process for Flood Mitigation

Slab-on-grade (SOG) homes along the Gulf of Mexico and other coastal areas are elevated above the base flood elevation to mitigate damage caused by repeated flooding events. This changes the slab support condition from uniform soil to column and beam supports, leading to unanticipated stress/strain changes, concrete cracks, and slab failure. However, no state or national code has design provisions for such risky operations. The current research was conducted to bridge this knowledge gap by developing a user-friendly App utilizing experimental and numerical study results. The experimental investigation evaluated the performance of elevated two- and four-panel specimens built per the construction practice along the Gulf Coast. The gathered deflection data from the test was used to calibrate a finite element model. Extrapolating on the slab model, five full-sized home foundation slab models were developed with differing support conditions, such as the number and spacing of columns and the presence of concrete grade or steel support beams. Model A could support up to 3.8 kPa without failure, while models B through E experienced welded wire fabric yielding at various configurations of column spacing. The induced stresses in the slab elements obtained from the parametric study were then compiled into a database used as the building block of the decision-making App. The tool allows users to choose a specific elevated slab and support configuration. It then outputs capacity and checks if it meets the minimum design live load established by the International Residential Code.