Ciria Report 108 Concrete Pressure On Formwork =link=

Prevent catastrophic blowouts that endanger site workers.

Using the correct pressure values ensures formwork does not bulge or fail (blowout).

The methodology outlines a step-by-step mathematical approach to determine the design lateral pressure, ensuring formwork is neither under-designed for safety nor over-designed to the point of financial waste. Step 1: Determine the Concrete Mix Group ciria report 108 concrete pressure on formwork

The report provides a comprehensive review of the factors influencing concrete pressure on formwork and offers practical guidance on how to:

High-dose retarding agents and advanced superplasticizers alter hydration kinetics beyond what the original CIRIA 108 charts anticipated. 5. Practical Site Tips for Formwork Safety Prevent catastrophic blowouts that endanger site workers

CIRIA 108 assumes internal vibration is stopped 1.5m below the current concrete level. If you over-vibrate (running the head too deep), you liquify the stiffened concrete, resetting the pressure to hydrostatic at that depth.

If placing concrete in winter, reduce the pour rate to compensate for the delayed setting times caused by low ambient temperatures. Step 1: Determine the Concrete Mix Group The

The report was written before the widespread use of highly fluid Self-Compacting Concrete (SCC). SCC typically requires designing for full hydrostatic pressure unless specialized testing proves otherwise.

Applying CIRIA 108, they measured the setting time (E) of the site mix (a high-density concrete with PFA) at 3.5 hours and controlled the rate of rise (R) to 1.2 m/hour. The resulting P_max was just 120 kN/m².