Soil testing and site classification glossary of terms

Design documentation glossary

The following are definitions of words commonly used in site classification reports and other engineering documentation.

Allowable Bearing Capacity

Maximum bearing pressure that can be sustained by the foundation from the proposed footing system under service loads which should avoid failure or excessive settlement.

Articulated full masonry

Full masonry construction in which special provision is made for movement by articulation.

Articulated masonry veneer

Masonry veneer construction in which the provisions for articulated masonry have been applied to the masonry veneer.

Bored pier

In-situ concrete cylindrical load support element.

Bulk pier

In-situ concrete load support element excavated by backhoe or similar.

Clad frame

Timber or metal frame construction with the exterior wall clad with timber or sheet material not sensitive to minor movements. Includes substructure masonry walls up to 1.5m high.

Clay

Fine-grained soil with plastic properties when wet. Includes sandy or silty clays.

Continuous footing

Footing of rectangular section.

Controlled fill

Material that has been placed and compacted in layers by compaction equipment within a defined moisture range to a defined density requirement in accordance with Clause 6.4.2(a) of AS 2870-2011 and AS 3798-2007.

Dynamic Cone Penetrometer (D.C.P)

Field equipment used to determine underlying soil strength by measuring the penetration of the device into the soil after each hammer blow.

Edge beam

Beam at the edge of a slab-on-ground or stiffened raft.

Edge footing

Footing at the edge of a footing slab. 

Foundation

Ground which supports the building.

Footing

Construction which transfers the load from the building to the foundation.

Footing system

General term used to refer to slabs, footings, piers and pile systems used to transfer load from the structure to the foundations.

Full masonry

Construction with masonry double-leaf external walls and masonry single-leaf internal walls without full articulation.

House

Detached single dwelling constructed as Class 1, or Class 10a as defined in the National Construction Code, with limitations as stated in AS 2870-2011.

Liquid limit (wl)

Moisture content at which the soil passes from plastic to the liquid state as determined by the liquid limit test.

Linear Shrinkage (LS)

Decrease in length expressed as a percentage of the original length when a sample of soil is oven-dried from a moisture content of about the liquid limit as determined by the linear shrinkage test.

Load-bearing wall

Any wall imposing on the footing a service load greater than 10 kN/m.

Masonry

Stone, brick, terracotta block, concrete block, or other similar building unit single or in combination assembled together unit by unit.

Masonry veneer

Hhouse construction consisting of a load-bearing frame clad with an outer leaf of masonry.

Pad footing

Concrete footing used to support a pier or stump.

Pier and Beam

Footing system incorporating bored piers, bulk piers or piles supporting a suspended slab and including a slab partly supported on piers and partly supported on ground.

Plastic limit (wp)

Moisture content at which the soil becomes too dry to be in a plastic condition as determined by the plastic limit test.

Plasticity index (lp)

Numerical difference between the liquid limit and the plastic limit of a soil.

Pocket penetrometer (PP)

Instrument used to evaluate consistency and approximate unconfined compressive strength of saturated cohesive soils.

Rock

Strong material including shaley material and strongly cemented sand or gravel that does not soften in water. Material that cannot readily be excavated by a backhoe may be taken to be rock.

Reactive site

Site consisting of a clay soil which swells on wetting and shrinks on drying by an amount that can damage buildings on light strip footings or unstiffened slabs. Includes sites classified as S, M, H, or E in accordance with Clause 2.1.

Sand

Granular soil that may contain a small proportion of fines including silt or clay. The amount of fines may be assessed as small by visual inspection or if the amount passing a 425 um sieve is 15% or less. Material with a higher proportion of fines shall be treated as silt or clay.

Services

Means all underground services to the site including but not limited to power, telephone, sewerage, water & stormwater.

Site

Address and/or lot description

Slit

Fine grained soil that is non-cohesive and non-plastic when wet, can include some sand and clay.

Slab-on-ground

Concrete floor supported on the ground and incorporating integral edge beams.

Surface movement (Ys)

Estimated movement at the surface of a reactive site caused by moisture changes.

Standard residential allotment

Means that if the lot/allotment is larger than 650 metres square then the client needs to identify where the proposed dwelling structure is to be erected.

Stiffened raft

Concrete slab on ground stiffened by integral beams and a grid of internal beams.

Stump

Element supported on a footing used for the support of a frame construction.

Waffle raft

A stiffened raft with closely spaced ribs constructed on the ground and with slab panels suspended between ribs.

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