What type of pile should only be used for a level load?

The selection of sheet piles is appropriate for level loads because they are specifically designed to provide lateral support and containment for soil, water, or other materials. Sheet piles are typically used in applications such as retaining walls or cofferdams, where they help maintain the stability of the structure under horizontal pressure exerted by the retained material. Their construction allows them to effectively resist horizontal loads, meaning they perform best when the load is evenly distributed and level.

In contrast, wood piles, bearing piles, and shell piles are designed to handle vertical loads or have different applications that do not primarily focus on level loads. Wood piles, for example, are generally used to support load-bearing structures and transfer vertical loads to the soil below. Bearing piles are designed to carry heavy loads and are driven deep into the ground, while shell piles are used for specific vertical applications, such as foundations. These differing purposes underscore why sheet piles are the correct choice for situations that involve level loads.