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Structural Concrete Frames 367
Soldiers
to sides
Struts
Formwork for
internal beams
Plywood decking to floor
Bearers
Ledgers on
steel props
Adjustable
steel props
Ply sides and base
to beam formwork
100 × 75 mm
bearers at 300 mm
centres
150 × 75 mm ledgers
19 mm plywood lining
to column formwork
100 × 75 mm
backing members
Adjustable steel
props as falsework
Steel column clamps
Figure 6.15 Formwork and falsework.
Figure 6.17. Falsework consists of adjustable steel props fixed as struts to the sides. Temporary
falsework and formwork are struck and removed once the concrete they support
and contain has developed sufficient strength to be self-supporting. In normal weather
conditions, the minimum period after placing ordinary Portland cement concrete that
formwork can be struck is from 9 to 12 hours for columns, walls and sides of large beams,
11–14 days for the soffit of slabs and 15–21 days for the soffit of beams.
Column formwork
Column formwork can be constructed from short wall panels, with the ends of the panel
overlapping (Figure 6.15, Figure 6.16 and Figure 6.17), or it can be constructed using specially
designed and fabricated column formwork (Figure 6.18, Figure 6.19 and Figure 6.20