This Architectural Drawing of AutoCAD of Sectional plan of Pile cap. All piles shall be reinforced with not less than 4 longitudinal steel bars having an area of not less than 1.25 percent and not more than 4.0 percent of the gross cross-sectional area of the pile. The materials used are long steel bars with longitudinal protrusions between the piles held in shape by thinner tie wires. Once this steel mat is laid, timber is attached around the perimeter to contain the wet concrete mixture. For more details and information download the drawing file.