The manufacturing process is divided into monofilament manufacturing and stranded wire manufacturing. Monofilaments are made by (cold) drawing technology. Depending on the product material, it can be high carbon steel wire rod, stainless steel wire rods wire rod or medium and low carbon steel wire rod. If zinc plating is required, the monofilament should be electroplated or hot-plated. In the manufacturing process of steel strand, many steel wires are twisted by twisting machine to make products, and the prestressed steel strand needs to be stabilized continuously after forming, and the final product is generally concentrated on a reel or the finished product is reel-free.

applied range

Galvanized steel strand is usually used for suspension wire, stay wire, core wire or reinforcement. It can also be used as grounding wire/ground wire for overhead transmission, obstacle cable on both sides of highway or structural cable in building structure. Prestressed steel strand is commonly used in uncoated prestressed concrete steel strand and galvanized steel strand, which are often used in bridges, buildings, water conservancy, energy and geotechnical engineering, and unbonded steel strand or single strand is often used in floor and foundation engineering.

Tension value calculation

Calculation of tension value of steel strand

The design control tension of prestressed tensioning construction of steel strand refers to the tension of steel strand before anchorage after prestressed tensioning is completed. Therefore, when calculating the theoretical elongation of prestressed tensioning of steel strand, the distance between anchorage points at both ends of steel strand should be taken as the calculated length of steel strand, but the control tension of steel strand during prestressed tensioning is controlled at the anchorage of jack tool, so for the convenience of control and calculation, the distance between anchorage points at both ends of steel strand plus the working length of steel strand in tensioning jack is generally taken as the calculated length of theoretical elongation of prestressed tensioning of steel strand. When the prestressed steel strand is tensioned, most of the exposed part of the steel strand is wrapped by the anchor and jack, so it is impossible to directly measure the tensile elongation of the steel strand. The tensile elongation of the steel strand can only be calculated by measuring the piston stroke of the tensioning jack, but at the same time, the retraction of the anchor should be reduced in the whole process of tensioning the steel strand. The bearing capacity of steel strand should be 4-6 times of total traction.

(Refer to Technical Code for Construction of Highway Bridges and Culverts) The general calculation formula is Δ L = Δ L1+Δ L2-b-c (1), where Δ L1:refers to the initial tension of the jack piston (generally 10%~25% specified in the bridge construction code) Δ L2: calculated elongation at initial stretching (calculated according to specifications); B: retraction amount of tool anchor plug; C: retraction of working anchor plug.