Four Common Problems and Solutions for Prestressed Anchorages

There are always some small problems with prestressed anchorages through production and cooperation with customers. Here, we have done sorting and analysis and listed four common problems and solutions to share with everyone.

1. The rust of anchorages, steel strands, and wedges causes slippage

The principle of the self-anchoring system is to bite the steel strand through the alveolar of the wedges and insert the wedges into the hole of the anchor head to lock the prestress. If the wedges cannot bite the steel strand because the rusty alveolar is filled with rust or other dirt, or the alveolar itself is rusted and the strength of the alveolar itself is reduced, it may cause slippage. In addition, the corrosion of the surface of the steel strand or the corrosion in the anchor head hole may cause resistance to the fit between the wedge and the anchor ring hole, which may cause the slip. If this happens, be sure to replace the steel strands and anchorages with new ones. And remind the construction personnel to try not to install the anchorages too early to prevent from rusting.

2. Mixed-use of anchorages, tool anchors, limit plates, and wedges from different manufacturers

In some projects, due to material procurement reasons, products from different manufacturers may coexist. Please handle this situation properly. The matching angle of the anchor head and wedges between different manufacturers is usually different, and it is absolutely not allowed to mix them. Once mixed, the consequences will be disastrous. In addition, the size of the limit plate of each manufacturer is also different, and the arrangement of the holes and the design of the limit size are also different. If they are mixed, it is easy to cause accidents.

3. The hole in the bearing plate is blocked

This problem is often encountered, and it is also a problem that is easily overlooked. The steel strand passes through the anchor head and passes through the bearing plate. If there is concrete in the bearing plate at this time, it just hits the steel strand, causing the steel strand to be unevenly stressed and even bent, which is very easy to break the strand. There may be no problem at the time of tension, the wedges and steel strand will suddenly fly out at a certain time after the tension, which is very dangerous.

4. The limit plate is installed incorrectly or not installed

An important part of the tensioning process is the limit plate. When installing, please remember that the anchor head must be completely installed in the groove of the limit plate in parallel. Each hole of the anchor head is required to pass through the limit plate in an unobstructed arrangement. The limit size must be consistent with the specified size by the manufacturer. If the limit size is too large or too small, problems are likely to occur.