Screw Pile Torque Monitoring: Direct vs Pressure
Screw-pile installation torque can be monitored in more than one way, but the methods are not equivalent. Contractors should understand the difference between direct driveline torque measurement and torque estimated from hydraulic pressure.
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Direct Torque Measurement
A direct torque monitor measures torque in the mechanical driveline between the hydraulic drive and the pile connection. Systems such as Torq-Hub and Torq Spool are intended to provide direct installation-torque data and can also support jobsite documentation depending on configuration.
Direct measurement avoids having to infer torque solely from hydraulic pressure.
Hydraulic Pressure-Derived Torque
A hydraulic pressure gauge measures system pressure—not torque directly. Pressure can be converted to an estimated drive output torque only when a valid pressure-to-torque relationship is available for the exact hydraulic motor/gearbox configuration.
The relationship is not universal. Motor efficiency, gearbox efficiency, pressure losses, relief-valve settings and the specific drive configuration all affect the result.
Installation Torque Is Not Automatically Pile Capacity
Helical-pile systems often use an empirical torque-to-capacity relationship such as Q = Kt × T. The torque factor Kt depends on the pile system, shaft geometry and supporting technical data. It should not be treated as one universal conversion factor for every pile.
The pile manufacturer and/or project engineer should establish the required installation torque, allowable pile torque, capacity relationship and acceptance criteria for the project.
Effective Torque vs Instantaneous Torque
Some pile systems use an average or “effective” installation torque over a specified final installation interval rather than one instantaneous peak reading. Follow the pile manufacturer's or project engineer's procedure for the specific pile system.
When a Pressure Gauge Is Useful
- Monitoring hydraulic pressure
- Setting or verifying pressure-relief limits
- Using a manufacturer-approved drive-specific pressure/torque chart
- Diagnosing hydraulic performance
When Direct Torque Monitoring Is Useful
- Recording actual driveline torque during installation
- Projects requiring torque documentation
- Reducing dependence on pressure-derived estimates
- Comparing installation torque consistently across a job
Choose the Right Interface
Torque monitors must match the drive/pile interface and required torque range. Rev-Pile carries Torq-Hub and Torq Spool configurations for multiple hex and square interfaces.
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