Few building materials available today offer the economy, flexibility and reliability of precast prestressed concrete. These general products are specially made for specific applications. Typical shapes of precast prestressed concrete piling are square, hexagonal, octagonal and round - solid or hollow. Piles are designed to resist compression, tension, bending and torsion forces during the manufacture, transportation, handling and installation so the structural integrity and design purpose are achieved. The CPCI Design Manual lists factored resistance for various pile cross-sections and concrete strengths. The capacity of a pile is determined by the ultimate shearing resistance of the soil along the sided of the pile and the resistance of the bearing strata underneath the pile tip. Commonly used methods to evaluate the bearing capacity of a pile are load testing, dynamic resistance to penetration during driving and static resistance analyses based on soil data and soil mechanics.