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Rankine Active Earth Pressure with Surcharge Calculator

Compute the Rankine active earth pressure resultant on a wall, including an additional uniform surcharge load behind it.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax
9.84 ft
Schematic, drawn to the proportions you entered — not to scale on screen.

Active pressure resultant

37 kN/m

Check your inputs

Assumes a uniform surcharge covering the full retained soil surface — a surcharge limited to only part of the backfill (e.g. a small equipment pad) distributes differently and needs a more detailed analysis.

Rankine active coefficient (Ka)
0.33
Soil weight component
27 kN/m
Surcharge component
10 kN/m

With the figures above, the active pressure resultant comes to 37 kN/m. Behind that figure, soil weight component is the biggest single quantity at 27 kN/m; start there if the total looks wrong. The method behind this is well established, though site conditions and material batches will move it somewhat. This is calculated for United States and cites IRC 2024. Building in another market? Change the selector above so the units and code reference follow.

Add the equipment this sizes

This result is a specification — 37 kN/m — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Rankine active earth pressure with a uniform surcharge: Pa = 0.5 x Ka x γ x H² + q x Ka x H, where q is the uniform surcharge pressure applied at the ground surface behind the wall

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Frequently asked questions

How does a surcharge increase pressure on the wall?
Any additional load on the ground surface behind the wall adds extra vertical stress throughout the retained soil, which the same active pressure coefficient converts into extra horizontal pressure — the surcharge effect is uniform with depth, unlike the soil's own weight, which increases with depth.
What common surcharges should I check for?
Parked vehicles, construction equipment, material stockpiles, adjacent building foundations, and even a sloped backfill (equivalent surcharge) — anything adding load to the ground surface within roughly the wall height's distance behind the wall.
Does this include a live-load impact factor?
No — for surcharges from vehicle traffic near the wall, check your local code for whether an impact factor or minimum design surcharge (many codes specify a default like 2 ft of equivalent soil height for vehicular areas) applies.