The Function and Installation of Prestressed Spiral Reinforcement of Anchorage
Everyone has a high level of concern or debate on the issue of prestressed anchorages, and one of the issues is the role of the spiral reinforcement of the prestressed anchorage. Some friends said that during the construction of the project, the construction team removed the spiral reinforcement of the anchorages. I wonder if there will be problems?
First of all, it needs to be explained that although the specifications and forms of anchorages are diverse in China, the basic working principles and components of the accessories are basically the same.
As an important part of the prestressed anchorage, spiral reinforcement has a very important role in engineering. In other words, since the manufacturer has configured spiral reinforcements in both the bridge anchorage and the rock/soil anchorage, the spiral reinforcement must play a very important role in the force of the prestressed tendon. Otherwise, manufacturers will not bother to produce spiral reinforcements.
In fact, the main function of spiral reinforcement is to improve the local compressive strength of reinforced concrete structures such as anti-slide piles, frames, ground beams, cushions, crossbeams, etc. at the anchor head.
Because the bearing plate is subjected to the pressure formed by the strong prestress of the anchor cable, in order to prevent the strong compressive stress from causing compression and shear damage to the reinforced concrete of the reaction structure, the use of spiral reinforcement can effectively form the stirrup effect in the structure. Form constraints on the reinforced concrete under the anchor. This effectively controls the compression fracture surface of the concrete under pressure.
Of course, as an auxiliary measure in the reaction force concrete structure, the spiral reinforcement needs to be sleeved together with the bearing plate on the reaction force structure before tying the reinforcement of the reaction force structure such as the frame, and closely connected with the steel reinforcement in the beam body. In the later stage of concrete pouring, it forms an overall force system with the reaction structure.
Installation of prestressed anchorage and spiral reinforcement
In the specific installation process, the spiral reinforcement must retain the thickness of the protective layer, and it needs to be close to the end mold, and then firmly welded to the main rib.
The installation sequence of prestressed anchorages should be spiral reinforcement, bearing plate, working anchor head, wedge, stressing jack, and tool anchorage from inside to outside.
At present, the main application of prestressed anchorages is the relevant specifications of the machinery industry, such as JGJ 85-2010 “Technical specification for application of anchorage, grip and coupler for prestressing tendons”.