Box Culvert: Design Calculations Eurocode 2021

For a 1m strip, given design moment M_Ed (kNm/m):

Example check for min/max reinforcement: A_s,min = 0.12% of concrete cross-section for C30/37 (ratio 0.0012). A_s,max = 0.04 A_c.

Eurocode 2021 permits:

Software compatibility: Most 2021 design software (SOFiSTiK, TEDDS, MIDAS Civil) now include EC2 2021 crack width recalibration.

For a 3 m span × 2 m height culvert with 1.2 m earth cover (γ_soil=18 kN/m³), LM1 traffic (UDL=9 kN/m² + TS=400 kN/axle reduced by deep cover factor α=0.8). box culvert design calculations eurocode 2021

ULM permanent load:
q_perm = γ_G × (weight of earth + self-weight) = 1.35 × (1.2×18 + 0.3×25) = 1.35 × (21.6 + 7.5) = 39.3 kN/m².

ULM variable load:
q_var = γ_Q × (reduced LM1) = 1.5 × (9 + 400/(3×2)) ≈ 1.5 × (9 + 66.7) = 113.6 kN/m². For a 1m strip, given design moment M_Ed (kNm/m):

Total design load q_U = 152.9 kN/m².

Mid-span +Moment (fixed-fixed frame approximate):
M_span = q_U × L² / 24 = 152.9 × 9 / 24 = 57.3 kNm/m width. Example check for min/max reinforcement: A_s,min = 0

Box culverts are typically analyzed as 2D frames (unit width strip). The 2021 updates encourage nonlinear soil-structure interaction using the Bedding Spring Method (EN 1997‑1, Annex H).

Box culverts are analyzed as rigid frames.