The design of cantilever retaining wall piers involves the structural engineering aspects of constructing a retaining wall using cantilever piers. These piers are designed to withstand the lateral pressure from the soil or earth they are supporting. The design process typically includes determining the soil properties, the load the wall will need to support, and the required stability of the structure. This involves calculations for the reinforcement, concrete mix design, and detailing the structural components to ensure the wall's integrity and longevity.