Types of Structural Loads
Dead Loads (Permanent Loads)
Dead loads are the self-weight of structural and non-structural elements that remain constant:
- Concrete slab: ~24 kN/m³
- Steel sections: ~78.5 kN/m³
- Brick masonry: ~20 kN/m³
Live Loads (Variable Loads)
Live loads vary during the structure's lifespan. Typical design values per EN 1991-1-1:
| Occupancy Category | Live Load (kN/m²) |
|---|---|
| Residential floors | 2.0 |
| Office floors | 3.0 |
| Retail floors | 4.0 |
| Assembly areas | 5.0 |
| Parking (cars) | 2.5 |
Load Combinations
For ultimate limit state (ULS) design per Eurocode:
F_d = 1.35 × G_k + 1.5 × Q_k
Where G_k is the characteristic dead load and Q_k is the characteristic live load.
Simply Supported Beam — Key Formulas
For a beam of span L with uniformly distributed load w (kN/m):
| Result | Formula |
|---|---|
| Max reaction | R = wL/2 |
| Max moment | M_max = wL²/8 |
| Max deflection | δ_max = 5wL⁴/(384EI) |
References
- EN 1990:2002 — Basis of structural design
- EN 1991-1-1:2002 — Actions on structures — Densities, self-weight and imposed loads