Tools › User guides › Retaining Wall Design Studio
The Retaining Wall Design Studio designs cantilever and counterfort retaining walls by the limit state method of IS 456: earth pressure (Coulomb or Rankine), optional seismic pressure by Mononobe–Okabe (IS 1893), stability against overturning, sliding and bearing, and the toe, heel, stem, counterfort and shear key with trial reinforcement you can adjust.
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| Field | What to enter | Typical value | Tip |
|---|---|---|---|
| Wall type | Cantilever or Counterfort (switch at the top). | Cantilever up to about 6–7 m | |
| Overall height of wall H | Top of wall to underside of base. | ||
| Founding depth below GL at toe Df | 1.2 – 1.8 m | ||
| Stem width at top / at base | Cantilever wall (uniform stem for counterfort). | top 0.2 – 0.3 m; base ≈ H/10 – H/12 | |
| Base slab thickness tb | ≈ stem base width | ||
| Toe / heel projection | Base width ≈ 0.5H – 0.7H; toe ≈ ⅓ of the base. | ||
| Length of wall | For quantities. | ||
| Counterfort spacing / width | Counterfort walls only. | S ≈ H/3 – H/2, width 0.3 – 0.5 m |
| Field | What to enter | Typical value | Tip |
|---|---|---|---|
| Unit weight of backfill γ | 18 – 20 kN/m³ | ||
| Angle of shearing resistance φ | 30° – 35° | ||
| Earth pressure theory | Coulomb or Rankine. | Rankine for vertical back / level fill | |
| Wall friction angle δ | Coulomb only. | ⅓ φ – ⅔ φ | |
| Backfill slope i | Slope of the fill above the wall. | 0° if level | |
| Pressure surface / thrust acts at | Vertical plane at heel or inclined stem face; H/3 or 0.42H. | Vertical plane, H/3 | |
| Uniform surcharge q | Traffic or stored load on the fill. | 10 – 20 kN/m² for roads | |
| Coefficient of base friction µ | 0.5 | ||
| Safe bearing capacity | From the soil report. | ||
| Unit weight of concrete | 25 kN/m³ | ||
| Fill wedge / soil over toe / shear key | Tick boxes; key depth and width when a key is provided. | A shear key helps when sliding fails. |
| Field | What to enter | Typical value | Tip |
|---|---|---|---|
| Include seismic case | Mononobe–Okabe pressure. | Zones III–V | |
| Zone factor Z, importance I, R, Sa/g, Av/Ah | IS 1893 values. | Z 0.16, I 1.2, R 2.5, Sa/g 2.5, Av/Ah ⅔ | |
| Add inertia of wall mass | Ah × W of the wall. | Ticked |
| Field | What to enter | Typical value | Tip |
|---|---|---|---|
| Grade of concrete / steel | M20 – M40; Fe 415 – Fe 550. | M25 – M30, Fe 500 | |
| Clear cover | Earth-facing faces. | 50 – 75 mm | |
| Toe, heel, stem, distribution, counterfort, ties, shear key bars | Diameter and spacing of trial bars. | Change them and every check updates; the summary shows pass / fail. |
Results: earth pressure coefficients, forces and moments, factor of safety against overturning (≥ 1.55) and sliding (≥ 1.4), base pressures within SBC, then the design of each part, a design summary, the reinforcement schedule and a section sketch with the base pressure diagram.
Cantilever walls are economical up to about 6–7 m; above that, counterforts tie the stem to the base and reduce the stem thickness and steel.
Increase the heel, tick “Provide shear key under base”, or include the soil over the toe if it will stay in place.