Straight-web sheet piles are calculated using the traditional earth pressure distribution method, without considering anchor point displacement or redistribution of earth pressure. For hot-rolled steel sheet piles, the calculated maximum bending moment can be reduced by 1/3 or multiplied by a reduction factor of 0.7-0.8 to serve as the standard bending moment for sheet pile cofferdams.

However, reductions are not permitted in the following situations:

1. Straight-web sheet piles lack tie rods, or the tie rods are not firmly anchored. Displacement may occur when the pile tip enters the soil, but earth pressure redistribution will not occur in this case;

2. Unconsolidated clay soil exists behind the wall;

3. The soil behind the wall does not reach the anchor rod elevation;

4. The soil behind the hot-rolled steel sheet piles from the harbor basin to the anchor system is backfill;

5. High-stiffness reinforced concrete sheet pile walls

High-stiffness reinforced concrete sheet pile walls have a per-meter stiffness n greater than 0.06. In these cases, the sheet pile wall should be calculated as a free-end load-bearing beam, and the resulting sheet pile bending moment should not be reduced. If n ≤ 0.06, it is recommended that the sheet pile wall be considered a flexible wall, constructed or partially embedded in the soil. The per-meter stiffness is calculated as follows:

In the United States, PS straight-web sheet piles are commonly used for cofferdams. Elsewhere, Arcelor AS sheet piles are more popular.

PS Sheet Piling Catalog