Date of Award
12-24-2025
Date Published
January 2026
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Civil and Environmental Engineering
Advisor(s)
Dawit Negussey
Keywords
Amphibious Foundation;Cold-Region & Permafrost Foundation Design;EPS Geofoam;Flood Mitigation;Geotechnical Engineering;Sustainable Design
Subject Categories
Civil and Environmental Engineering | Civil Engineering | Engineering
Abstract
Flood frequency and severity continue to rise due to climate change enhanced sea level rise, heavier rainfall, and abnormal snowmelt, as well as continued development and population increase in flood-prone areas. Such events have caused repeated billion-dollar losses in the United States and globally, with housing among the most severely affected sectors. To quantify recent impacts, this study examined the spatial distribution and economic losses of major U.S. flood disasters from 1980 to 2025 based on records from NOAA National Centers for Environmental Information (NCEI). All historical loss data were inflation-adjusted to 2025 prices. Additional archival sources, including regional news reports, municipal flood logs, and documented field observations, were reviewed to contextualize event-scale impacts. To extend the historical perspective, flood losses over the past 150 years were retrieved from the NOAA National Weather Service (NWS). Traditional flood hazard mitigation measures, such as sandbags, berms, and other Federal Emergency Management Agency (FEMA)-recognized options (elevation, barriers, rebuilding, relocating, dry and wet floodproofing), remain widely used but often provide limited protection, require significant labor and time, and are less accessible to low-income communities. These mitigation options were compared based on U. S. Army Corps of Engineers (USACE) post-flood inspection reports and emergency barrier systems evaluations. The record of documented failures of flood resistant barriers and FEMA-endorsed mitigation practices indicate success rate of only about 23% for protecting homes during major floods. Floating homes are common along some canals, riverbanks and lake shores in many countries. Floating homes rise with flood levels and remain relatively immune to flood-induced hazards. Amphibious homes remain ground supported on dry land but become buoyant during flooding. Upon recession of flooding, amphibious homes gradually transition back to ground supported dwellings. FEMA guidelines and recommendations for alternative flood hazard mitigation options do not include amphibious homes. The development and types of amphibious homes were reviewed and compared to inform the improvement direction covered in this investigation. So far, amphibious homes rely on separate support systems for dry land and floating states or depend on watertight dry floodproofing. The inherent limitations and disadvantages of separate support systems and dry floodproofing are addressed in the thesis. This study proposes an amphibious shallow foundation system using expanded polystyrene (EPS) geofoam mat that can also float the house at times of flooding. The proposed system overcomes both separate support and dry floodproofing system limitations. The feasibility assessment of the proposed alternative model was developed based on ASCE and FEMA criteria and advisory guidelines. Both the compression load bearing and uplift capacity in buoyancy of the EPS geofoam foundation system were simulated in ABAQUS finite element models. The material characterization parameters for the EPS blocks were selected based on review of lab test results and data from field observations. Prior experience and results of finite element simulations indicate EPS geofoam blocks of 1.25 pcf (20 kg/m3) density can support homes on dry land and float houses during flooding. Indicated compression stresses and strains under design loads were small and tolerable. EPS blocks of 2 ft (0.6 m) thickness provide adequate buoyancy to float houses with about 1 ft (0.3 m) freeboard or factor of safety of 2. Simulations of heat flow and insulation performance suggest amphibious foundations can maintain a livable house floor level over multiple cycles of freezing and thawing, as in places like Nunapitchuk, Alaska. Overall, the research results encourage trial consideration to include amphibious foundations in advisory flood hazard mitigation and freeze / thaw damage reduction strategies.
Access
Open Access
Recommended Citation
Sun, Zhiwen, "Amphibious Foundation for Flood Hazard Mitigation" (2025). Dissertations - ALL. 2240.
https://surface.syr.edu/etd/2240
