12.7mm unbonded PC Strand

12.7 A brief introduction to unbonded prestressed steel strands I. Basic concepts 12.7 Unbonded prestressed steel strands are a special type of steel used in prestressed concrete structures. Their "unbonded" characteristics mean that the steel strands are not directly bonded to the concrete, but isolated by a protective layer wrapped around the outside of the steel strands. This design allows the steel strands to slide freely when subjected to force, thereby reducing friction losses and improving the durability and construction convenience of the structure. II. Structural composition and specifications Structural composition Steel strand body: usually made of 7 high-strength steel wires, with a diameter of about 12.7mm, and a standard tensile strength of 1860MPa (high-strength steel). Protective layer: The outer layer is wrapped with a high-density polyethylene (HDPE) sheath, and the interior is filled with anti-corrosion lubricating grease, which plays a role in waterproofing, corrosi…