Soil testing and site classification is conducted to identify a variety of issues which must be considered when planning to build on a specific site. Reduced bearing capacity is a problem that must be recognised and addressed. This is a common issue in Brisbane where many suburbs are built on natural clay deposits.

Where a site is to be built on clays, the same moisture susceptibility that caused shrinking and swelling of clays also reduces their capacity to bear weight. As these clays absorb water, they become soft, much like playdough. When a load such as a footing or foundation is applied to these soft, low bearing capacity soils, the foundations move and affect the stability of the building. Damage may occur as a result.

It is not uncommon to see fill brought to a site that contains a significant amount of clay. Often this material is placed over what are otherwise stable local soils. It is possible in this situation to “import” problems to your site when utilising uncontrolled fill. This problem can be avoided by utilising controlled fill for which engineering properties are known.

The post Potential Issues Identified in Soil Testing and Site Classification – Bearing Capacity. first appeared on Express Soil Testing.

In the early 1990’s, rules were introduced to ensure that every new building and extension or development project would have a soil test and site classification completed prior to construction. Prior to this there had been increasing concern regarding construction standards of footings and foundations as numbers of defective houses steadily increased. A lack of knowledge and consideration for local site conditions resulted in poorly designed slabs and footings which in turn resulted in damage to building structures over time. In the past damage to structures due to site soil conditions has varied from minor to sever and in the worst cases led to buildings being demolished due to safety concerns. Australian Standards hence created the AS 2870 site classification standard to limit building damage due to site movement and provide a set of standardised foundation designs particular to certain site parameters. In the case where potentially hazardous site conditions are identified during a site classification and soil test inspection, a site specific design must be created with the input of a qualified engineer. This standard is adhered to today by councils across Australia including Brisbane, the Sunshine Coast and the Gold Coast. All building development applications, including extensions, must now be accompanied by a site soil test report and site classification when submitted to local council.

The post Why do I need a Soil Test? first appeared on Express Soil Testing.