Flat web sheet piles work differently from other sheet piles. Most sheet piles rely on their bending strength and stiffness to retain the soil or water. Flat sheet piles are formed in circles and arcs to create gravity cells. The cells are held together through the tensile strength of the interlock. The tensile strength of the lock and the allowable rotation of the lock are the two main design characteristics. The flat sheet pile cells can be made to huge diameters and heights and withstand a great deal of pressure.
AS Sheet Piles are the strongest flat sheets piling in the world. The high interlock strength allows very tall, large diameter cells to be built. The AS sheets can swing 4.5 degrees per interlock for most piles and any pile over 65.6 feet (20 m), in length has 4.0 degrees of allowable swing. There are a total of five different thicknesses for the AS 500 series, allowing the piles to be sized to fit almost any project.
The PS Sheet Piles are an American-made flat sheet with a very large allowable swing. The 6.2 degree swing per interlock allows designers to configure very small cells. There are currently two PS sections made and they can handle almost all flat sheet piling requirements.