| What is pre-stressed strand, what performance characteristics |
Standard official name: prestressed concrete strand Steel Strand for Prestressed Concrete
Actually used "pre-stressed strand" This referred to Prestressing steel strand, PC Strand
Prestressing strand is 2,3,7 or 19 high-strength steel wire rope consisting of twisted, and by eliminating the stress treatment (stabilized) for prestressed concrete or similar purposes.
Classification
According to a strand of wire can be divided into the number 2 wire strand, 3 strand wire, 7 wire strand and 19 strand wire. Smooth surface morphology can be divided according to strand, strand nicks, pull the strand die (compact), galvanized steel wire, epoxy coated strand and so on. Can also follow the diameter, or intensity level, or standard classification.
Specifications meaning
In the description and list of tables we seen, there are 15-7Φ5 ,12-7Φ5 ,9-7Φ5 other model specifications prestressed strand. To 15-7Φ5, for example, 5 indicates the nominal diameter of 5.0mm wire, 7Φ5 said the seven components of such a steel wire strand, while 15 said that 15 of this strand composed of a bunch of steel, the overall meaning is " a bunch of 7 from the 15 wire (diameter of each wire 5mm) steel strand composed of. "
Manufacturing methods
High-carbon steel wire rod, cold drawn through the surface treatment into the wire, and then press the strand structure of the synthesis of a certain number of shares of twisted steel wire, through the elimination of stress from the stabilization process. To extend the durability, the wire can be metal or non-metallic coating or coatings, such as galvanized, coated with epoxy resins. To increase the bond strength with concrete, the surface can have nicks and so on. Mode pulling the prestressed steel strand after strand through a die in the compression process, the structure is more compact, more suitable anchor grip surface. Produced no strand (unbonded steel strand) the ordinary pre-stressed strand, anti-corrosion grease or paraffin coated high-density polyethylene bag (HDPE) to become.
Features
The main characteristics of prestressing strand, high strength and relaxation properties, and the other to start, than straight. 1860 MPa tensile strength level is common, there 1720,1770,1960,2000,2100 MPa kind of intensity level. This higher yield strength of steel,
Application
In most post-tensioned and pre-tensioned prestressed project, smooth strand is the most widely used in prestressed steel. Mode is mainly used to enhance the engineering strand pulling, but also for projects like nuclear power. Galvanized steel wire commonly used in bridge tie, cable and external prestressing works. The use of epoxy coated strand and galvanized prestressed strand similar.
National standards
Countries have standards for pre-stressed strand, such as: China Standard GB / T 5224, American Standard ASTM A416, British Standard BS 5896 and the Japanese standard JIS G3536, Australia and New Zealand Standard AS / NZS 4672, the Brazilian Standard NBR-7483 |
|
