Brief introduction of bonded prestressed steel strands
I. Definition and core structure
Basic concept: The steel strands are bonded to concrete as a whole through grouting. After tensioning, the channels are filled with cement slurry to form a coordinated force system.
Structural composition: It is composed of 7 high-strength steel wires twisted together (commonly used diameter 15.2mm), with a smooth or scored surface, and relies on the grouting layer to achieve bonding with concrete.
II. Key characteristics
Bonded force: Stress is transmitted to the concrete through the grouting layer, and the whole section works together with good crack resistance.
Low relaxation advantage: Stress relaxation rate after heat treatment is ≤2.5% (small deformation under long-term load).
Anti-corrosion dependence: The grouting layer isolates corrosion, but the density must be ensured (such as vacuum-assisted grouting).
III. Application scenarios
Bridge engineering: prefabricated T-beams, continuous box…