📊 Dynamic Piling Formula (Driven Piles)

Engineers use the Engineering News-Record (ENR) Formula to determine allowable pile capacity. [2]

Ra = 2 x E x W x H / ( S +C)

Key Variables

• Ra: Allowable pile capacity.
• W: Weight of the ram.
• H: Height of the fall.
• E: Hammer efficiency rating.
• S: Final penetration per blow.
• C: Empirical constant (based on hammer type).

🧪 Bored Piling Formula (Cast-in-Place) [6]

For drilled shafts, total capacity combines skin friction and end bearing resistance.

Qu = Qs + Qb = f_s x A_s + q_b x A_b

Key Variables

• Qu: Ultimate pile capacity.
• Qs: Shaft resistance (skin friction).
• Qb: Base resistance (end bearing).
• fs: Unit skin friction.
• As: Surface area of shaft.
• qb: Unit base resistance.
• Ab: Cross-sectional area of base.