Polyurethane Foam Foundation Footings for Load-Bearing Structures
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Solution Overview
Problem
Conventional concrete footings for raised foundation systems are inefficient due to high labor costs, carbon footprint, porosity, and limitations in cold temperatures, and they require large water quantities, while existing polyurethane foam applications do not effectively increase load-bearing capacity.
Innovation Solution
The use of closed-cell, hydrophobic polyurethane foam compositions with a mixture of polyisocyanate and active hydrogen-containing compounds to create a foundation footing system where the foam fills the gap around a post, providing a strong adhesive bond and increased load-bearing capacity, and can be cured quickly in various temperatures, including below freezing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional concrete footings are used for raised foundation systems, then the footing provides structural support, but labor costs and carbon footprint increase significantly
Solution Approach 1:
The patent changes the material parameter from concrete to polyurethane foam, which has different physical and chemical properties including lower density, faster curing time, and reduced carbon footprint while maintaining adequate load-bearing capacity through proper formulation and cell structure control
Solution Approach 2:
The patent replaces the mechanical mixing and pouring process of concrete with a chemical foam expansion process where liquid polyurethane components react and expand in-situ, eliminating the need for heavy machinery, formwork, and extended curing time associated with concrete
2Strength
If conventional concrete footings are used, then structural support is provided, but carbon footprint and environmental impact increase
Solution Approach 1:
The patent changes the material composition from cement-based concrete to polyurethane foam, which has significantly lower embodied carbon and environmental impact while providing equivalent or superior structural performance through its cellular structure and material properties
3Strength
If conventional concrete footings are used, then footing structure is formed, but porosity and water absorption occur
Solution Approach 1:
The patent uses polyurethane foam with a controlled cellular structure that provides the desired mechanical properties while being inherently water-resistant, eliminating the porosity and water absorption problems associated with concrete through the closed-cell foam structure
Solution Approach 2:
The patent employs polyurethane foam as a composite material that combines the benefits of light weight, structural integrity, and water resistance in a single material system, whereas concrete requires additional waterproofing treatments to achieve similar performance
4Strength
If conventional concrete footings are used, then foundation support is provided, but large quantities of water are required
Solution Approach 1:
The patent changes the material from concrete to polyurethane foam, which does not require water for mixing or curing, eliminating the water consumption associated with concrete production and installation while maintaining footing capacity through the foam's structural properties
5Strength
If conventional concrete footings are used in cold temperatures, then footing can be formed, but curing time increases and strength development is limited
Solution Approach 1:
The patent changes the material from concrete to polyurethane foam, which cures through a chemical reaction that is not dependent on temperature-driven hydration processes, allowing for rapid strength development even in cold temperatures where concrete curing would be severely limited
Solution Approach 2:
The patent replaces the temperature-dependent chemical hydration process of concrete with a polyurethane foam expansion and curing process that can proceed effectively across a wider temperature range, eliminating the curing time delays that occur in cold weather concrete construction
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The polyurethane foam system reduces labor and transportation costs, is more environmentally friendly, and provides a durable, water-resistant footing that can support loads effectively, with adhesive bond strengths exceeding 1200 pounds per foot and compressive strengths between 40 to 100 psi, allowing for efficient load distribution and resistance to frost heave.
Implementation Method 1
a cured, closed-cell, polyurethane foam surrounding the post, wherein the polyurethane foam fills the gap between the post and sides of the hole, the polyurethane foam comprising a cured mixture of a polyurethane composition comprising polyisocyanate and at least one active hydrogen containing compound
Implementation Method 2
closed-cell, hydrophobic polyurethane foam compositions
Data Source
AI summary
Foundation footing system for a load-bearing structure comprising a hole in the ground and a post in the hole extending above the hole. A gap present between the sides of the post and the sides of the hole contains a cured, hydrophobic, closed-cell, polyurethane foam to firmly hold the post in place and protect the post from moisture. Alternatively, a foundation footing system for a load-bearing structure comprising a hole in the ground filled with a cured, hydrophobic, closed-cell, polyurethane foam and a post place on and connected to the top of the foam.