A slab-on-grade foundation involves pouring a monolithic concrete slab that serves the primary structural element and rests directly on prepared subgrade soil. This type of foundation is engineered for efficient load transfer and simplified construction under specific ground conditions. Below is a breakdown of the slab-on-grade foundation system:
Structural and Material Specifications
Concrete Slab Specifications: The slab typically has a 100 mm to 200 mm thickness and is reinforced with A615 steel rebar or ASTM A185 welded wire mesh. It is key that the slab can handle varying loads and environmental pressures. We use a reinforcement schedule that strengthens it, reducing the risk of cracking.
Before pouring the concrete, it’s crucial to prepare the ground thoroughly. The subgrade is compacted and graded thoroughly to distribute the weight evenly and keep the structure solid. Soil tests help determine how compact it needs to be to avoid uneven settling.
To prevent moisture from causing problems like heaving or cracking, it’s important to install a special barrier made of high-density polyethylene plastic. This barrier stops moisture from seeping up from the ground into the concrete.
In places where the ground freezes, add insulation around the edges and under the slab. This insulation, usually made of a type of foam, helps keep the temperature steady and prevents frost from pushing the slab up.
Design Considerations
Load-Bearing Capacity: The slab-on-grade is specifically made to distribute imposed loads directly to the supportive soil stratum. Finite element analysis may be employed to simulate load distribution and identify potential stress concentration points.
Thermal Dynamics: Thermal modelling assesses the slab’s response to structure fluctuations, particularly in regions with significant seasonal variations, to enhance the slab’s resistance timing and thawing cycles.
Types of Slab-on-Grade Foundations
Integrated Monolithic Slabs: These are characterized by a continuous pour that forms both the footing and the slab. The periphery of the slab is thickened to serve as the footing, enhancing the foundation’s load-bearing capabilities and structural resilience.
Independent Floating Slabs: These are decoupled from the footing or foundation walls and designed to float independently to accommodate soil movement caused by moisture variations or other dynamic soil conditions.
Advantages
Cost-Effectiveness: This foundation type is generally less resource-intensive, requiring fewer materials and labour, translating into lower overall construction costs.
Construction Expediency: Eliminating complex foundation layering reduces construction phases, facilitating a faster project turnaround.
Limitations
Geotechnical Restrictions: The applicability of slab-on-grade foundations is contingent on the absence of expansive clay soils and areas devoid of deep frost penetration unless specifically engineered with adaptive measures.
Maintenance of Embedded Utilities: Modifications or repairs to utilities embedded within the slab, such as hydraulic or electrical conduits, require invasive procedures that can disrupt the slab’s structural slab’.
Typical Applications
Slab-on-grade foundations are optimal for structures within temperate to warm climates. They are predominantly utilized in residential, commercial, and light industrial buildings with stable and non-reactive ground conditions.
For Your Reliable Foundation Repair Needs – Just a Call Away!
