Custom Bridge Construction Machine Prestressed Post Tension Hydraulic Stressing Jack

Features of Hydraulic Core Hollow Jack​

1. YDC Types Stressing jack is a general-purpose prestressed through-heart jack, which is used for tensioning operations of various steel strand anchorages. Widely used in post-tensioning large buildings, structures, prestressed concrete bridges, rock anchoring, hydraulic structures, foundation anchoring, and other major projects.
2. The main parts of the jack are made of high-strength steel, which has the characteristics of compact structure, lightweight, small volume, short axial length, and short reserved tension length of steel strand, which can save steel strand material. And the hoisting is flexible, durable, easy to operate, and easy to maintain.
3. YDC type jack is a kind of feed-through jack, which is a multi-purpose prestressed tensioning equipment. It is easy to operate, mainly used for single-hole tensioning, and can also be used for long and short preloading. Tensioning and troubleshooting, and suitable for high-strength steel wire bundles and strands of various specifications.

Installation of Post-Tension Jack and Anchorage

1. The steel strand shall be threaded into the reserved gallery of the structure, and the exposed length of the steel strand at the tensioning end is required to be 200-250mm longer than the working length of the jack. The steel strand must be cut with a thin disc grinder without loose ends or "rough ends" to avoid difficult perforation.

2. Cover the end of the steel wire bundle of the working anchor plate, push it to the anchor base plate, and align it with the spigot.

3. Installation of working anchor clips: before installing clips, use steel rings to clamp each pair of clips together, then push them into the taper hole of the anchor plate along the steel strand, and then push them until they do not move.

4. Installation of limit plate: the limit plate is designed according to the working anchor plate and matched with the hole of the anchor plate.

5. Installation of jack: first bind the end of the steel strand bundle with a wire pin, then lift the jack and put it on the steel strand, and put the support opening of the front cover of the jack on the outside of the limit plate. At this time, the jack can be coaxially aligned.

6. Install the tool anchor on the support lip at the end of the piston.

Background Technique of Post-Tension Jack and Anchorage
Prestressing engineering is to apply pre-tensioning stress to the steel bars in the tension module before the structural components of the engineering are subjected to external loads, so as to improve the stiffness of the components, delay the appearance of cracks, and increase the durability of the components. Generally, a through-type dry jack is used for prestressed tendon tensioning construction. There is a through-type dry jack as shown in Figure 1, which includes a cylindrical oil cylinder 105 and a piston 103 installed in the oil cylinder 105. The piston 103 A through-center sleeve 104 is inserted, and the through-center sleeve 104 is installed in the oil cylinder 105 through the rear sealing plate 102. The oil cylinder 105 is located at the outer end of the rear sealing plate 102 and is provided with a rear end cover 101 crimped with the through-center sleeve 104. The oil cylinder The front end of 105 is fitted with a front sealing plate 106. Because the feed-through sleeve is installed and fixed in the oil cylinder by the rear sealing plate and the rear end cover, the feed-through jack is large in size and heavy in weight. The maximum working oil pressure is about 50MPa, and the working load (ton) and body weight (kg) ratio is 1:0.7~1.5, that is, the weight of the feed-through dry jack with a working load of 100 tons is 70Kg~150Kg; it is difficult to move during the prestressed tendon tensioning construction operation, the construction efficiency is low, and the operator labor intensity is high.