Introduction of Prestressed Anchorages for Bridges

prestressed anchorage for bridges
  1. YJM15 series, YJM13 series stressing anchorages are also called circular anchorages.

YJM13 series anchorages can anchor Φ12.7 steel strands, and YJM15 series can anchor Φ15.24 steel strands. This anchorage has good anchoring performance and self-anchoring performance. Tensioning these anchorages generally use YDC series multi-strand jacks.

The stressing-end anchorage is composed of four parts: anchor head, wedge, bearing plate, and spiral reinforcement. The wedge is the key part of the anchor system, and it is in the form of two-piece or three-piece, and is made of high-quality alloy steel.

  1. BJM15 series, BJM13 series flat anchorages

Flat anchorages are mainly used for lateral prestressing of bridge decks, hollow slabs, and low-height box girders to make the stress distribution more uniform and reasonable, and further reduce the thickness of the structure. Tensioning flat anchorages generally use QYC series mono-strand jack.

Prestressed anchorage tensioning precautions:

  1. The prestressed anchorages should be properly kept, and there should be no rust, water and other dirt when using, and no current should be conducted. Before installing the anchorage, please remove the rust and dirt on the steel strand of the anchoring section, so as to avoid the rust and dirt filling the tooth of the wedge and causing slippage during tensioning.
  2. Please strictly check the strength and diameter of the steel strand. When the steel strand is corroded, it cannot be tensioned. Before installing the anchor head, please check whether there is a phenomenon of leaking slurry bonding the prestressed tendons in the tunnel, and if so, it should be removed in time.
  3. The working wedge can be used after removing the wrapping paper. However, when the prestressed tendon is longer (over 36 meters) or the single tendon exceeds 12 strands, a small amount of lubricant should be applied to the hole of the anchor heade so that the wedge can be withdrawn and anchored to avoid wire breakage.
  4. When installing the anchorage, the anchor head should be aligned with the mouth of the bearing plate, and the wedge should be flush after installation. Use special tools to tap lightly when necessary, but do not damage the wedge with heavy knocking.
  5. During the tension, it is necessary to match the corresponding limit plate and tool anchor head according to the standard of the working anchor.
  6. During the tension, the operator shall not move directly in front of the anchorage, and shall not hit the steel strand or anchorage with gravity. When removing excess steel strands, the anchors should be protected from the heat of cutting, and it is recommended to use the grinding wheel for cutting, and electric welding and oxygen cutting are prohibited.
  7. Before sampling the static load test, the wedge and anchor head holes should be cleaned, and the wedge device should be symmetrical and flush, otherwise it will affect the static load test performance.

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