Pile Driving Energy & Dynamic Formula Calculator
Estimate pile bearing capacity using Engineering News Record (ENR) and dynamic principles. Features a database of hammer efficiencies and material compression constants.
About
Estimating the static load-bearing capacity of driven piles is a fundamental task in deep foundation engineering. While static load tests are the most accurate they are expensive and time-consuming. Dynamic formulas allow engineers to estimate capacity in real-time based on the behavior of the pile during the driving process specifically the "set" or penetration per blow.
This calculator employs a modified Engineering News Record (ENR) approach solving for ultimate resistance based on hammer energy delivered to the pile head. It accounts for system losses through efficiency ratings and temporary elastic compression of the pile cap and soil. This ensures a more realistic safe load estimation than simple gravitational potential energy calculations.
Formulas
The tool estimates Ultimate Bearing Capacity (R) using a dynamic energy balance equation:
Where S is the final set (penetration per blow), C is the temporary compression constant, and Eff is hammer efficiency. Note that a Factor of Safety (usually 6.0 for standard ENR) must be applied for Allowable Load.
Reference Data
| Hammer Type | Efficiency (Eff) | Typical Energy Range |
|---|---|---|
| Drop Hammer (Winched) | 0.70 - 0.75 | 10 - 50 kJ |
| Diesel (Single Acting) | 0.75 - 0.85 | 20 - 100 kJ |
| Hydraulic Hammer | 0.85 - 0.95 | 30 - 300 kJ |
| Pile Material | Compression (C) | Elasticity Note |
| Concrete Pre-cast | 2.5 mm | Low Elasticity |
| Timber / Wood | 5.0 mm | High Elasticity |
| Steel H-Pile | 1.0 - 2.0 mm | Very Stiff |