Ciria Report 108 Concrete Pressure On Formwork

The report doesn't give one number; it gives a maximum pressure (( P_max )) based on the slower of two rates:

Pressure characteristics and influencing factors ciria report 108 concrete pressure on formwork

Published in 1985, CIRIA Report 108 ( Concrete Pressure on Formwork The report doesn't give one number; it gives

That’s where comes in. Despite being nearly 40 years old, it remains the gold standard guidance for calculating lateral pressure on vertical formwork in the UK and beyond. But the report details five distinct concrete types

Most engineers memorize the rule of thumb: Pressure is 110 kN/m² or ( 2.4 \times R ), whichever is lower. But the report details five distinct concrete types (ST1 to ST5) and their rheology.

Back to Basics: Why CIRIA Report 108 Still Rules Concrete Pressure Design

The primary criticism of R108 is its age. The concrete mixes tested in the 1980s differ from modern high-performance mixes. Today's self-compacting concrete (SCC) and heavily admixed designs behave differently; SCC, for example, exerts nearly full hydrostatic pressure because it remains fluid longer and lacks the internal friction of standard mixes. R108’s formulas may underestimate pressures for these modern specialized mixes.