Prestressed anchor for PC steel strand used in bridge, railway sleeper, ground anchor
2019-11-04 13:34:27
Concrete prestressed anchor was first used at the end of the 19th century and its development has exceeded pre-tensioning, including post tensioning, which was carried out after casting concrete. The tension system can be divided into single strands (where each strand of strand or wire is separately stressed) or multiple strands (all strands or wires in one of the strands are simultaneously stressed). The ribs can be located within the concrete volume (internal prestressed) or outside the concrete volume (external prestressed). Prestressed concrete anchor uses ribs that are directly bonded to the concrete, while post-tensioned concrete can use bonded or unbonded ribs.
Prestressed anchor anchorage is a variant of prestressed concrete in which the tendons are tensioned prior to casting the concrete. The concrete is bonded to the tendons during the solidification process, and then the ends of the tendons are released and anchored, and the tendon tension is transmitted to the concrete by static friction as compression.
Prestressed anchorage is a common prefabrication technique in which the final concrete component is manufactured remotely from the final structural location and transported to the site once cured. It requires a firm and stable end anchorage point that stretches between these anchor points. These anchors form the ends of the "casting bed" which may be many times the length of the concrete element being manufactured. This allows multiple components to be constructed end-to-end in a pre-tensioning operation, resulting in significant productivity gains and economies of scale.
This compression is produced by tensioning high-strength "ribs" located inside or adjacent to the concrete and can improve the performance of the concrete in use. Tendons can be made up of single-strand, multi-strand or threaded rods, which are usually made of high-strength steel, carbon fiber or aramid fiber. The essence of pretension prestressed anchor is that once the initial compressive force is applied, the resulting material has the characteristics of high-strength concrete when subjected to any subsequent compressive forces, and has the characteristics of ductile high-strength steel when subjected to tensile forces. In many cases, this can increase structural capacity and/or service life compared to conventional reinforced concrete. In prestressing concrete members, internal stresses are introduced in a planned manner to offset the stresses generated by the superimposed loads to the desired extent.
Compared to simple reinforced concrete, concrete prestressed anchor can be used in a wide variety of architectural and civil buildings, and their improved properties extend the span, reduce structural thickness and save material. Typical applications include high-rise buildings, residential slabs, foundation systems, bridge and dam structures, silos and storage tanks, industrial pavements and nuclear containment structures.
