Concrete Footings Pouring

The main hazards include trench collapse (especially in sandy or waterlogged soils), concrete burns from alkaline wet concrete (pH 12-13), struck-by from concrete trucks and pump booms, manual handling injuries from heavy work in confined trenches, underground services strikes, silica dust from cutting operations, and noise/vibration from concrete vibrators.

Under WHS Regulations, any trench deeper than 1.5m requires shoring, shielding, or battering unless a geotechnical assessment confirms the soil is stable. However, all trenches should be assessed by a competent person regardless of depth, as shallow trenches in sandy or waterlogged soil can also collapse.

Wet concrete has a pH of 12-13 (highly alkaline) due to calcium hydroxide content. This causes severe chemical burns that may not be immediately painful. Burns can progress to third-degree within 2 hours of skin contact. Always wear alkali-resistant gloves, waterproof boots, and cover all skin.

BYDA (Before You Dig Australia, formerly Dial Before You Dig) is a free referral service that provides plans showing the location of underground services (electrical, gas, water, telecommunications). It is a legal requirement to check for underground services before any excavation work. Over 20,000 underground utility strikes occur in Australia annually.

Workers should avoid entering trenches during concrete placement wherever possible. The weight of wet concrete (approximately 2.4 tonnes per cubic metre) and vibration from concrete vibrators can destabilise trench walls. If entry is necessary, the trench must be shored and a competent person must assess conditions.

Essential PPE includes alkali-resistant gloves (nitrile or butyl rubber), waterproof safety boots with steel caps, safety glasses, hard hat near plant and trucks, high-visibility vest, and long clothing covering all skin. Add hearing protection when operating concrete vibrators and P2 respirator for any cutting operations.

AS 2870:2011 (Residential Slabs and Footings) is the primary standard for residential footing design. AS 3600:2018 (Concrete Structures) covers concrete quality and placement requirements. AS 1379:2007 specifies concrete supply requirements including maximum placement temperature of 35°C.

Concrete footings should cure for minimum 7 days under Australian conditions before any loading. Full design strength is typically achieved at 28 days. Curing should begin immediately after finishing - apply curing compound or cover with wet hessian and plastic sheeting to retain moisture.

Call 000 immediately. Do NOT enter the collapsed trench as there is a high risk of secondary collapse. Do not attempt manual digging to rescue buried workers. Account for all workers on site. Keep bystanders clear. Wait for emergency services with appropriate technical rescue equipment.

A competent person must inspect and sign off formwork before concrete is ordered. Checks include: formwork dimensions match engineering drawings, bracing is secure, bearing surfaces are stable, connections are tight, no damage or warping, reinforcement is correctly positioned and tied, cover blocks are in place, and formwork is clean and oiled.