The "H" method, as presented in CIRIA Report 108, is a widely used approach for estimating concrete pressure on formwork. The method assumes a linear pressure distribution with depth, with the maximum pressure occurring at the bottom of the pour. The pressure (P) at any point is calculated using the following equation:
P = (ρ × g × h) × (1 + (α × V))
A case study was conducted on a recent high-rise building project in London. The project involved pouring a large concrete slab using a climbing formwork system. The CIRIA Report 108 method was used to estimate the concrete pressure on the formwork. The results showed that the maximum pressure occurred at the bottom of the pour, with a value of 65 kN/m². The formwork was designed to withstand this pressure, and the pour was completed successfully without any incidents. ciria report 108 concrete pressure on formwork