It focuses on the calculation methodology, load combinations, and reinforcement design based on Eurocode requirements applicable around 2021 (incorporating the UK National Annex, though principles apply across Europe).
- Minimum reinforcement: $\rho_min = 0.26 \cdot (f_ctm/f_yk)$ but not less than $0.0013$ for slabs.
- Crack control (for watertightness, serviceability):
Maximum crack width $w_max = 0.2 , mm$ (for culverts with groundwater exposure).
Note: Recent 2021+ updates to the second generation (e.g., EN 1992-1-1:2023) are merging these into a single part to cover bridges and liquid retaining structures simultaneously.
Define the clear internal dimensions (width $W$, height $H$) and preliminary wall/slab thickness ($t$). A common rule of thumb for initial thickness is:
For serviceability limit state (SLS): γ_G = 1.0, γ_Q = 1.0 (rare combination) or 0.6 for quasi-permanent.