What factor of safety is used for pile design?

Traditional ASD: FOS = 2.0-3.0 on ultimate capacity. FOS = 2.0 when load tested, 2.5 when wave equation analysis used, 3.0 based on static analysis alone. LRFD resistance factors: φ = 0.45-0.75 (AASHTO).

What is the difference between friction and end-bearing piles?

Friction (floating) piles derive capacity mainly from skin friction along shaft. End-bearing piles reach hard stratum and derive capacity from tip. Most piles have both components; design philosophy depends on soil profile.

How is skin friction calculated by the alpha method?

Alpha method (cohesive soils): f_s = α·c_u where α = adhesion factor (0.5-1.0 depending on c_u). API method (offshore): α = 1.0 for c_u < 25 kPa, decreasing to 0.5 for c_u = 100 kPa.

Pile Capacity Calculator

Calculate ultimate pile capacity: Q_ult = Q_tip + Q_skin = q_p·A_p + f_s·A_s. Meyerhof method for driven piles. Alpha method for cohesive soils. Beta method for effective stress. Allowable Q = Q_ult/FOS (FOS=2-3).

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)

σy — Normal Stress Y (MPa)

τxy — Shear Stress (MPa)

⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.

How to Use

Enter the values for the patient or scenario you are assessing. Calculate ultimate pile capacity: Q_ult = Q_tip + Q_skin = q_p·A_p + f_s·A_s. Meyerhof method for driven piles. Alpha method for cohesive soils. Beta method for effective stress. Allowable Q = Q_ult/FOS (FOS=2-3). Use the pile capacity result to inform your clinical assessment.

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Frequently Asked Questions

What factor of safety is used for pile design?

What is the difference between friction and end-bearing piles?

How is skin friction calculated by the alpha method?