Sheet pile wall
A steel sheet pile wall, cantilever or with one row of anchors, in layered soil with water on both sides and a uniform surcharge: the penetration, the anchor force, the moment and first yield of the section, by UFS 3-220-20 (DM7.2, 2026) 4-7.
Inputs of the sheet pile #
- Retained height H, anchor depth, surcharge. DM7.2 4-4.2: about 300 psf is common for storage and equipment.
- Water behind and in front: depths below the top. The difference is a net water pressure, carried to the tip with no drop for seepage, as in DM7.2's example. A depth past the tip means dry.
- Soil layers: up to 6, top down, the last running on. Moist and saturated unit weights, φ, c or su. For clay in undrained terms, φ 0 and c the undrained strength. Ka, Kp: 0 takes Rankine. Enter a log spiral Kp with wall friction if your geotechnical engineer gives one.
- Factor of safety on passive: divides passive pressure. Enter 1.0 if your Kp is already factored. DM7.2 uses 1.5 to 2.
- Factor on the depth: 1.2 for scour and future dredging.
- S, I, Fy, E per foot of wall: from the manufacturer. 18.1 in³/ft and 84.4 in⁴/ft are PZ-22 (DM7.2 Table B-9), prefilled with its 38.5 ksi. There is no sheet pile table in the app, so auto-design is not offered.
- Rowe's reduction: anchored walls only, for penetration in medium dense or better sand. None is the safe side.
- Loss to corrosion: a share of S. Default 0, with an advisory, as the service life and exposure are yours.
The design method sets the steel check only: H with its load factor, 1.6, against φ Mn; or H against Mn / Ω. Earth pressures stay unfactored with the factor on passive.
Checks performed #
| Result | Basis |
|---|---|
| Net pressure | DM7.2 4-7: active plus water behind, factored passive in front |
| Anchored: D from moments about the anchor, T from equilibrium | DM7.2 Figure 4-37, free earth support |
| Cantilever: rotation point and D from force and moment equilibrium | DM7.2 Figure 4-41 |
| Design penetration | D × your factor, rounded up to a foot |
| Rowe | DM7.2 Eq. 4-31, Figure 4-36 |
| Flexure, first yield | Mn = Fy S, AISC 360-22 Chapter F factors |
| Advisory: corrosion | Left at 0 |
Limitations #
- Not checked: global stability, seepage and piping, basal heave, interlock strength, deflection, axial load, and the driving of the pile.
- The anchor rod, wale, connections and deadman are not designed. One row only.
- Level ground, no sloped backfill. No tapering of net water below the dredge line. No limited surcharges: use the Lateral pressure from surface loads type and judge how to carry it over.
- Rowe reduces the anchored moment only as DM7.2 states it.
Verification examples #
Verification status: 14 values compared in 3 examples (3 published, 0 hand calculations from the cited equations): 13 within tolerance, 1 recorded deviations. Code basis: the provisions it uses were read in the target edition.
| Example | Source | Values |
|---|---|---|
| Anchored bulkhead, 24 ft | UFS 3-220-20 Appendix B-2, pp. 606 to 614 | D 14.45 ft, design 18 ft, T 9,568 lb/ft, connections 11,400 lb/ft, zero shear 4.57 ft, M 63.4 kip-ft/ft, ρ 18.52, factor 0.62, design M 39.3 kip-ft/ft, S 12.25 in³/ft |
| Cantilever in sand, 15 ft | Figure 4-43, p. 245 | D 14.25 ft and M 31,590 lb-ft/ft read off a chart |
| Cantilever, sand over clay, 20 ft | Figure 4-45, p. 247 | D 17.2 ft and M 51,840 lb-ft/ft read off a chart |
The cantilevers come from DM7.2's charts, not from a calculation shown line by line, so they compare at 5 %. The Figure 4-43 moment, run on the example's stated soil, is 8 % below the printed value, a documented deviation on the less conservative side. Caltrans Trenching and Shoring Chapter 7 has only soldier pile examples. The steel check has no published value here: DM7.2's example divides by Fy with no margin. USACE EM 1110-2-2504 and USS Steel Sheet Piling Design Manual would add examples and a section table, and they were not on hand.