Box Culvert Design Calculations Eurocode 2021 May 2026

Box Culvert Design Calculations — Eurocode (2021) — Quick Practical Guide

Scope & assumptions

• Purpose: reinforced-concrete rectangular box culvert for highway drainage.
• Design code: Eurocode suite (EN 1990 / EN 1991 / EN 1992 / EN 1997) as consolidated to 2021 guidance.
• Typical assumptions used here: concrete C30/37, steel B500B, exposure class XC2, service life 50 years, design working life ultimate limit state (ULS) and serviceability limit state (SLS) considered. Adopt partial factors per Eurocode (γM, γF) typical values: γM = 1.15 (material), γF = 1.35 (actions) for ULS. Use SI units.

Cracks & detailing: Provide H10 @ 150 mm secondary reinforcement on inner face (temperature & shrinkage). Corner U-bars: 2H16 each leg, L-bars with 50 mm cover.

Load Model 1 (LM1):

1. Self-weight (dead) – 25 × 0.25 = 6.25 kN/m² (slabs), walls = 6.25 kN/m run.
2. Earth vertical – 30 kPa on top slab.
3. Earth horizontal – triangular on walls (15 to 35 kPa).
4. Traffic surcharge – 66 kPa patch positioned at critical location (midspan for top slab, or edge for wall bending).

Step 3 – Bending moments (linear elastic frame): box culvert design calculations eurocode 2021