Retaining & slopes · Reinforced soil & gabions
MSE wall with steel strips calculator
External sliding, overturning and bearing, plus Kr, maximum tension, pull-out and tension checks at every strip layer of an inextensible-reinforcement wall.
Standard: FHWA-NHI-10-024 simplified method · AS 4678 concepts
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Inputs in the worked example
The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.
| Input | Value | Unit |
|---|---|---|
| Wall height H | 6 | m |
| Strip length L | 4.8 | m |
| Vertical spacing Sv | 0.75 | m |
| Horizontal strip spacing Sh | 0.75 | m |
| Strip width b | 50 | mm |
| Allowable tension per strip (after corrosion loss) | 40 | kN |
| Pull-out factor F* at the top (≤ 2.0) | 2 | |
| Reinforced fill γ | 20 | kN/m³ |
| Reinforced fill φ′ | 34 | ° |
| Retained soil γ | 19 | kN/m³ |
| Retained soil φ′ | 30 | ° |
| Foundation φ′ | 30 | ° |
| Foundation γ | 19 | kN/m³ |
| Surcharge q | 10 | kPa |
| Surcharge | Permanent (counts for pull-out) |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Ka (fill) / Ka (retained) | 0.283 / 0.333 | |
| Layers | 8 | |
| Max strip tension Tmax | 23.99 | kN |
| Lowest pull-out FS | 1.77 | at z = 5.63 m |
| Sliding FS | 2.48 | |
| Overturning FS | 4.80 | |
| Eccentricity e (limit L/6 = 0.80) | 0.500 | m |
| Bearing pressure (Meyerhof) | 161 | kPa |
| Ultimate bearing | 825 | kPa |
| Bearing FS | 5.13 |
- ✓ Sliding FS ≥ 1.5
- ✓ Overturning FS ≥ 2.0
- ✓ e ≤ L/6
- ✓ Bearing FS ≥ 2.5
- ✓ Pull-out FS ≥ 1.5 at every layer — 1.77
- ✓ Tmax ≤ allowable per strip
- ✓ L ≥ max(0.7H, 2.4 m)
Method, formulas and assumptions
- Kr/Ka = 1.7 at the top falling to 1.2 at 6 m and below (steel strips)
- Tmax = Kr·σv·Sv·Sh, σv = γr·z + q
- F* = 2 at the top falling to tan φ′r at 6 m; Pr = F*·α·σv·Le·C·b with C = 2, α = 1
- Active zone (coherent gravity): 0.3H wide in the top half, 0.6(H − z) below; Le = L − La
- z = 0.38 m: Kr 0.472, Tmax 4.64 kN, Le 3.00 m, Pr 10.07 kN, FS 2.17
- z = 1.13 m: Kr 0.454, Tmax 8.30 kN, Le 3.00 m, Pr 17.08 kN, FS 2.06
- z = 1.88 m: Kr 0.436, Tmax 11.66 kN, Le 3.00 m, Pr 22.60 kN, FS 1.94
- z = 2.63 m: Kr 0.419, Tmax 14.72 kN, Le 3.00 m, Pr 26.63 kN, FS 1.81
- z = 3.38 m: Kr 0.401, Tmax 17.49 kN, Le 3.22 m, Pr 31.35 kN, FS 1.79
- z = 4.13 m: Kr 0.383, Tmax 19.95 kN, Le 3.68 m, Pr 37.01 kN, FS 1.86
- z = 4.88 m: Kr 0.366, Tmax 22.12 kN, Le 4.13 m, Pr 40.93 kN, FS 1.85
- z = 5.63 m: Kr 0.348, Tmax 23.99 kN, Le 4.58 m, Pr 42.44 kN, FS 1.77
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.