Frequently Asked Questions

What’s the difference between single and double-acting tension jacks?

Single-acting jacks push in one direction using hydraulic power (extending) but rely on springs or gravity for return. Double-acting models use hydraulic force for both extension AND retraction, giving you better control. Double-acting post-tension and stressing jacks cost more but offer precision during the critical release phase when tensioning concrete structures.

How do I determine the right stroke length of the post tension jack for my tensioning project?

Consider your anchor type and embedment depth. Longer strokes save time by reducing the number of “resets” during tensioning but add weight and bulk. Most contractors match stroke length to their typical tendon elongation plus some safety margin. For residential slabs, 6” strokes usually suffice. Multi-story structures might need 10-12” strokes for efficiency. Tell us your project specifics for targeted recommendations.

What safety precautions should I take when using post tensioning equipment?

Never stand in line with the tender! Catastrophic failures send cables whipping with deadly force. Check hoses for damage before pressurizing the post tension jack. Use calibrated gauges and never exceed the manufacturer's pressure ratings. Secure the jack heads properly on anchors. Never put your hands between the jack and the concrete during operations. Wear safety glasses and gloves. And always assume cables could break, positioning yourself accordingly.

Why is my hydraulic post tension or stressing jack not building pressure?

First, check your pump’s release valve – it is often accidentally left open. Next, inspect hydraulic connections for leaks or loose fittings. Air in the system? Bleed it by cycling the jack without a load. Low oil level in your pump reservoir can also cause this problem. If these quick fixes don’t work for your post tension jack, look for internal bypass issues, which may require a seal replacement kit.

How often should my post tensioning equipment and jacks be calibrated?

It is industry-standard to have calibration every 6 months or 500 tensioning cycles, whichever comes first. Some inspectors demand certificates dated within 90 days of use. Between formal calibrations, use a load cell to spot-check occasionally. Erratic pressure readings or drifting forces definitely indicate that recalibration is needed ASAP!

Can I use any hydraulic pump with these tensioning jacks?

It’s important to note that not just any pump will do! The post tension jack’s requirements must be matched to the pump’s pressure rating – typically 10,000 PSI for post-tensioning work. Flow rate affects tensioning speed: for most, 45-65 in³/min works best for efficiency without overheating.

What maintenance extends the life of post tension orstressing jacks?

Clean your jack after EACH use – concrete dust is the enemy! Store with the piston retracted to protect the chrome from damage. Change hydraulic oil every 500 working hours using ISO 32 or equivalent. Inspect seals monthly for leakage. Those tiny drips? They’re not harmless – they can indicate the post tension jack’s impending failure. Apply grease to the threads and pivot points weekly during heavy use.