Construction methods · Cast-in-place concrete decks

Falsework and temporary works engineering

Every cast-in-place method relies on a temporary structure that carries the wet concrete, the crew and the plant. Falsework has killed more construction workers than any permanent structure; the procedures that prevent it are as much a method as any formwork.

How bridges get built · Cast-in-place concrete decks · Falsework and temporary works engineering

Also called: temporary works design, falsework check, temporary works coordinator

Falsework and temporary works engineering — concept diagram — Concept diagram (TheBridgeEng)

How it is done

Appoint a temporary works coordinator; register every temporary structure with a design and an independent check.
Design for wet concrete, construction live load, wind, lateral loads (2.5 % of vertical minimum), pump surge and foundation settlement.
Inspect before loading with a permit to load; monitor during the pour; strike only on the engineer's release after strength tests.

Where it fits

Every project with formwork, falsework, cofferdams, travellers, gantries or trestles.

Where it does not

Treating the supplier's catalogue as a design; loading before the permit.

Plant, pace and money

PlantNone; it is procedure and engineering.

ProductivityAdds days of engineering, saves lives.

Cost1-3 % of temporary works cost.

Risks and controls

What goes wrong

The collapse of falsework, cofferdams and gantries: Willow Island (1978), Injaka (1998), several MSS collapses since 2000.

Quality assurance

Design and check certificates, permit-to-load records, striking release records.

Examples

BS 5975 in the UK codifies the whole procedure.