Ciria Report 108 Concrete Pressure On Formwork -

Concrete with higher workability (slump) generally causes higher pressures. 3. The CIRIA Report 108 Calculation Model

Categorized by specific modern consistency classes (F1 to F6). Detailed assessment of modern chemical additives. Not fully covered (developed post-report). Explicitly covers SCC up to full hydrostatic pressure. Integrates SCC characteristics. Limitations of CIRIA 108

Do you still use the CIRIA 108 nomographs, or have you moved to pressure sensors and digital monitoring?

): The vertical speed at which the formwork is filled (measured in meters per hour). Faster pouring rates create higher pressures because the concrete climbs higher before the lower layers can set. Concrete Temperature (

), which often led to massive over-designing of formwork. CIRIA 108 recognized that concrete is not a perfect fluid; it undergoes stiffening, hydration, and internal friction during the pouring process, which limits the maximum pressure exerted at the bottom of a tall pour. 2. Key Factors Influencing Formwork Pressure ciria report 108 concrete pressure on formwork

CIRIA Report 108 remains the definitive guide for calculating lateral pressures of fresh concrete on vertical and inclined formwork in the UK construction industry. While it predates the current European standards (EN 12812), it is widely regarded as the most practical and reliable document for this specific aspect of temporary works design. It bridges the gap between complex rheological theory and the pragmatic needs of a site engineer.

ACI uses distinct empirical formulas split explicitly between walls and columns. ACI relies heavily on chemistry factors ( CCcap C cap C ) and unit weight factors ( CWcap C cap W

CIRIA Report 108 (1985) serves as a foundational technical guide for calculating lateral concrete pressure on formwork, offering methods based on concrete mix, placement rate, and temperature. While widely adopted for temporary works design and standards like BS 5975, the method has limitations with highly flowable or self-compacting concrete. For the full report, visit CIRIA Bookstore AI responses may include mistakes. Learn more Form pressure generated by fresh concrete

vary depending on whether the structure is classified as a wall or a column, dictated by the cross-sectional dimensions). (Temperature Coefficient): Calculated as Detailed assessment of modern chemical additives

ACI 347 uses empirical curves based on column size. CIRIA 108 is more scientific for walls and unusual geometries because it explicitly accounts for the concrete's hydration chemistry. For complex projects, many engineers run both and use the higher (safer) value.

(Deducted 0.5 only due to the need for supplementary guidance on modern admixtures).

Establish the planned rate of pour (R) in m/h, concrete temperature, and density. Calculate Maximum Pressure ( Pmaxcap P sub m a x end-sub ): Use the formulas to find the maximum lateral pressure.

Based on the recommendations in CIRIA Report 108, here are some best practices for managing concrete pressure on formwork: Integrates SCC characteristics

CIRIA Report 108: Concrete Pressure on Formwork (1985) is a seminal industry standard used to calculate the lateral forces exerted by fresh concrete on vertical formwork. It replaced the older CIRIA Report 1 (1965) to better account for modern developments like chemical admixtures and blended cements. Core Calculation Methodology

) based on concrete density, rate of rise, and temperature coefficients, distinguishing between wall and column applications. Detailed information on the 1985 report is available at CIRIA . Concrete Pressure Analysis per CIRIA 108 | PDF - Scribd

CIRIA Report 108: Evaluation of Concrete Pressure ... - Studocu