- OUR PRODUCTS
Current wedges supplied, both 2,64mm and 4mm wedges respectively are split into two segments and are held together using a wire clip.
2,64mm and 4mm wedges respectively have an ultimate load of 60KN and a maximum service load of 40KN
Only ever use the wedges and barrels we supply together with one another as it is advised by our supplier that uniformity is of utmost importance.
- HOW IT WORKS
The prestressing process is one in which allows for prestressed wire to be stressed to a certain capacity whereby once achieved, the barrels and wedges hold the prestressed wire in place eliminating slippage.
Prestressing is usually handled from one side of the casting bed.
When stressing is conducted using a hydraulic jacking system, the jack should be held directly inline with the casting bed to ensure no barrels, wedges or wire failure occurs. The jack should be placed over the prestressed wire and held flush up against the barrel and wedge whereby the jaw will clamp the wire and pull the wire directly towards the ram of the jack. We recommend that jacks with an ease off option be used as if the jack releases suddenly, both barrel and wedge could be damaged in the process.
On release, wedges and barrels should never be struck when removed by an object. Such could cause damage to the teeth of the wedges and could crack the structure making the product unusable.
- QUALITY CONTROL
Barrels are manufactured from high quality alloy steels that have undergone crack testing and prove to be free of distortion.
Wedges are manufactured from case-hardened steel and once produced, undergo a series of tests to ensure the highest possible quality.
Barrels are guaranteed by our supplier to be free of cracks and are tested twice before leaving our suppliers
factory via ultrasonic equipment. Once approved, the barrels are stamped and sent out.
Our supplier ensures us that wedges undergo a series of static and tensile tests.
The testing process done by our supplier proves to be both manual and automatic.
- CLEANING AND MAINTAINCE
Maintenance is key for these barrels and wedges after each use and ensures greater longevity. The products should be brushed and lubricated regularly. Lubrication doesn’t only allow for maximum usage but also saves time and effort when detensioning after casting. Some of the most popular lubricants are:
- Powdered graphite
- Moly type aeresol spray
- Teflon sprays
Instructions are given by the manufacturer of lubricant on how to use the lubricants in the correct way.
- SAFETY INFORMATION
It is prohibited to use prestressing steel (strand) of an actual strength exceeding 2200 MPa.
OnIy use carefully cleaned, inspected and lubricated wedges since the failure of wedges can lead to life-threatening situations.
It is crucial that barrels and wedges never be hit/knocked/struck in any way with a hard solid object
Unnecessary high wearing situations that should be avoided are as follows:
- The length of the wire being tensioned at the ends of the bed is too short, causing the wedge“jaws”to fracture.
- Incorrect detensioning of individual wires resulting in slippage.
- SERVICE LIFE
Herewith, we reference service life of the product directly from our supplier:
The service life of the wedges depends very much on how well they are cleaned and lubricated but the hardness of the prestressing wires or strands and their shape and the stressing force applied also affects the life of the wedges and so it is impossible to give any absolute indication of how many times the wedges
can be used. The information given below is thus a very rough guide. The actual life of the wedges will vary from one application to another.
Service life of clamping jaws in hydraulic stressing grips: 500-5000 stressing operations
Service life of clamping jaws in mechanical stressing grips: 100-1000 stressing operations