This code covers the geotechnical and structural design, construction, and execution of various types of concrete pile foundations (driven, bored, cast-in-situ, and precast). It provides comprehensive guidelines for estimating pile load capacities, group spacing, concrete mix requirements, and installation tolerances.
Provides comprehensive guidelines for the design and construction of various types of pile foundations for structures.
Quick Reference Values
ratio of under ream to shaft diameter2 to 3 (usually 2.5)
minimum spacing between piles2 times under-ream diameter (2Du)
minimum grade of concreteM 20
minimum longitudinal reinforcement0.4 percent of the gross cross-sectional area of the pile shaft
minimum clear cover to longitudinal reinforcement40 mm
vertical spacing between two under reams1.25 to 1.5 times the under-ream diameter
Key Formulas
Qu = Ap * Nc * cp + α * c * As + ... (Static formula for ultimate bearing capacity of under-reamed pile in clay)
Safe Load = Ultimate Bearing Capacity / Factor of Safety (Usually 2.5)
Practical Notes
Under-reamed piles are highly effective in expansive soils to counteract heave due to moisture changes.
Ensure proper cleaning of the borehole base and under-reamed bulbs using a bucket auger before placing concrete.
If high groundwater table is encountered, concrete must be placed using a tremie pipe to prevent cement wash-out and segregation.