The steel grade of sheet pile

Sheet piles are widely used for earth-retaining structures. These can be designed as cantilever walls for continuous retaining walls and cofferdams, or as braced cuts when dealing with deep excavations for building.

A sheet pile wall must resist the following loads once it has been installed at the site:

1. Lateral earth pressures under static conditions

2. Lateral earth pressures due to earthquakes

3. Hydrostatic pressures due to porewater pressure buildup at the retained side

 4. Surcharge load at the top of the retained side (e.g., traffic load, construction load)

A sheet pile wall is generally idealized as a flexural member, as it mainly resists bending stresses from the abovementioned loads. Its strength can be determined from two components: the geometric property of the sheet pile, and the grade of the material to be used.

 For a sheet pile wall, a large portion of the cross-sectional area is located far from the neutral axis of the section. Should a sheet pile section have a large depth, higher values for the moment of inertia, I, and the section modulus, S, are expected. This in turn makes the sheet pile perform better in terms of bending.



Apart from the geometric properties of the sheet pile, the grade of the material shall also be considered when selecting the appropriate section. Sheet piles are most often made of structural steel. Compared to other construction materials, steel has yield strength, and is generally ductile in nature. The yield strength of steel varies widely and is dependent on various factors such as the chemical composition and manufacturing process. Material and testing standards also play a critical role in steel yield strength, as some projects would require certain material standards and/or specifications to be met as part of the detailed engineering design.