Calculations › RC One-Way Slab
RC One-Way Slab
EN 1992-1-1
Checks a one-way spanning RC slab in bending, shear and deflection to EN 1992-1-1.
Diagram
Example inputs
Span4000 mm
Slab thickness h180 mm
Cover25 mm
Superimposed dead load (gk)1.5 kN/m²
Imposed load (qk)3 kN/m²
Concrete gradeC25/30
National annexUK
Results
RC Slab — 180mm, 4000mm span
C25/30 · EN 1992-1-1
Results
✓ Bending PASS
util 0.4825.20EN 1992-1-1 §6.1
| Self-weight = h × γc | 4.5 | kN/m² | |
| wEd total ULS load = 1.35(gk+sw) + 1.5qk | 12.6 | kN/m | |
| d effective depth = h − cover − φ/2 | 149 | mm | |
| MEd design moment = wEd × L² / 8 | 25.2 | kNm/m | EN 1992-1-1 §6.1 |
| K bending parameter = MEd / (fcd × b × d²) | 0.08 | — | |
| K' limiting parameter | 0.168 | — | |
| z lever arm = d[0.5 + √(0.25 − K/1.134)] | 137.62 | mm | |
| As,req reinforcement = MEd / (fyd × z) | 421.16 | mm²/m | EN 1992-1-1 §6.1 |
✓ Shear PASS
util 0.2625.20EN 1992-1-1 §6.2.2
| VEd design shear = wEd × L / 2 | 25.2 | kN/m | EN 1992-1-1 §6.2.2 |
| k size effect factor = 1 + √(200/d) | 2 | — | |
| vRd,c concrete shear strength = 0.18/γC × k × (100ρfck)^(1/3) | 0.651 | N/mm² | EN 1992-1-1 §6.2.2 |
| VRd,c shear resistance = vRd,c × b × d | 97 | kN/m | EN 1992-1-1 §6.2.2 |
✓ Deflection PASS
util 0.6726.85EN 1992-1-1 §7.4.2
| ρ0 reference reinforcement ratio = √fck / 1000 | 0.005 | — | |
| ρ required reinforcement ratio = As,req / (b × d) | 0.003 | — | |
| Basic span/depth ratio = EN 1992-1-1 Eq 7.16 | 35.06 | — | EN 1992-1-1 §7.4.2 |
| σs steel stress (quasi-permanent) = fyd × wQP / wEd | 207.04 | N/mm² | EN 1992-1-1 §7.4.2 |
| Stress correction factor = 310 / σs | 1.497 | — | EN 1992-1-1 Eq 7.17 |
| L/d actual = span / d | 26.85 | — | |
| L/d limit = basic ratio × stress correction | 40 | — | EN 1992-1-1 §7.4.2 Table 7.4N |
WARNINGS
Shear check uses minimum concrete capacity — no shear links assumed. Verify this is appropriate.
Deflection check uses span/depth ratio method with assumed As,prov = As,req.
Try it yourself
Run this calc with your own inputs