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Soil Nail Pull-Out Safety Factor Calculator

Check a soil nail's pull-out safety factor against the standard FHWA minimum of 2.0.

Computed in your browser — nothing you enter is uploaded. Figures are presented in United States units and terminology, and each formula’s basis is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

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

Pull-out safety factor

3.557 (target ≥2.0)

High confidence

PASSES the standard FHWA minimum pullout safety factor of 2.0.

Pullout capacity
284.57 kN

With the figures above, the pull-out safety factor comes to 3.56 (target ≥2.0). This is presented for United States. Building in another market? Change the selector above and the units and terminology follow.

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 — a confirmed fix gets a permanent check of its own, so the same mistake cannot come back.

Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.

Regulatory standards & verification citations

  • FHWA GEC No. 7 soil nail wall design: pullout capacity = nominal bond strength x pi x drill hole diameter x bonded length; a minimum pullout safety factor of 2.0 is standard practice

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Frequently asked questions

Why does soil nailing need a pullout safety factor specifically?
Pullout (the grout column sliding out of the surrounding soil) is one of the primary failure modes for a soil nail — the safety factor ensures a comfortable margin between the design load and the actual resistance the bond can provide.
What if my bonded length seems very long?
Weaker soils (lower bond strength) need proportionally longer bonded lengths to develop the same capacity — this is normal and expected in soft or loose soil conditions.
Should I always use FHWA GEC-7 bond strength values?
They're a reasonable starting point for preliminary design, but site-specific pullout testing (required on most soil nail projects before or during production) gives a much more reliable bond strength value for your actual soil and installation method.