Breaking it Down - Understanding Foundations for your Build, Soil Movement and Ensuring Building Stability
The Hidden Choreography of Buildings
Ever wondered why your home seems to have its own subtle dance moves? Buildings can sway and groove, not just figuratively, but literally. This intricate dance is often tied to the foundation soil beneath your feet. In this blog, we’ll uncover the rhythm of building movements and explore the soil types that play a major role.
Unveiling the Soil Types: Granular vs. Clay
The foundation soil beneath residential areas is like the stage where this dance unfolds. Meet the main performers – granular and clay soils. Often, it’s a mix of both. Granular types might be prone to erosion, while clay soils face challenges like saturation and swell/shrink issues.
Decoding Soil Classifications: Navigating the Unreliable Terrain
Classifying soils in your area might sound like a straightforward task, but it often resembles a dance with uncertainty. Local authorities provide classifications, but their reliability can be questionable. Enter the geotechnical report – your trusted dance partner in understanding the soil beneath your home. As most buildings grapple with movement issues on clay soils, we’ll emphasize classifying soils based on their swell and shrink tendencies. Check out Table 2.1 from AS 2870, the Residential Slab and Footing Code, for a clearer view. https://ncc.abcb.gov.au/editions/2019-a1/ncc-2019-volume-two-amendment-1/part-32-footings-and-slabs/part-325-footing
Causes of Movement: From Construction Waltzes to Erosion Jigs
Construction sets the tone for the dance of settlement. Immediate settlement, where the building finds its footing, can vary based on soil types. Cohesive clay mitigates against it, but granular soils, especially sandy ones, are more susceptible. Consolidation settlement, a feature of clay soil, might take months or even years to fully unfold. These are challenges for the builder, and Building Technology File 19 (BTF 19) is the playbook that addresses them head-on.
Erosion, Saturation, and the Seasonal Waltz
Soils are vulnerable to erosion, with sandy soil being the prima ballerina in this scenario. Clay soils, on the other hand, can drown in saturation, losing their bearing capacity. Seasonal swelling and shrinkage, the slow dance of clays with water, bring their own set of challenges. Discover how these movements impact your home and learn how to keep the dance floor stable.
Shear Failure: When the Music Stops
Shear failure is the point where the music stops – when the foundation soil can’t bear the weight of the footing. Post-construction causes include significant load increases, reduced lateral support, and, in clay soils, saturation issues. It’s the grand finale of challenges, and we’ll help you understand the moves to prevent it.
Site Classes: Where Your Home Likes to Groove
We conclude with a cheat sheet of site classes, from the ‘Stable Dance Floor’ to the ‘Watch Your Step’ zones. Discover where your home likes to groove and ensure it’s on solid ground.
Conclusion: Navigating the Dance Floor of Homeownership
Understanding the dance of building movements is crucial for any homeowner. Armed with knowledge, you can ensure your home sways with elegance rather than stumbling through instability. So, let’s keep the dance floor steady, and may your home continue to waltz through the years with grace and resilience.
General Definitions of Site Classes
Most sand and rock sites with little or no ground movement from moisture changes.
***Stay tuned for more insights into the fascinating world beneath your home.***