Description of Automatic Hydraulic Stressing Jack

The prestressed tensioning jack is a special tensioning jack used for prestressed construction such as tensioning steel hinge lines. The prestressed jacks are all through-center hydraulic double-acting jacks. The prestressed jacks need to be used in conjunction with the high-pressure oil pump. The power for tensioning and returning to the top is provided by the high-pressure oil of the high-pressure oil pump. According to the different structures, it is divided into a mono jack and a multi-strand jack.

Technical Parameter of Automatic Hydraulic Stressing Jack

Features of Automatic Hydraulic Stressing Jack​

1. The prestressed jack has a compact structure, works smoothly during tensioning, and has a large tension force due to high oil pressure. It is widely used in prestressed construction projects such as highway bridges, railway bridges, hydropower dams, and high-rise buildings. The tension jack has the characteristics of large output force, lightweight and long-distance operation;

2. The electric hydraulic jack is equipped with the ultra-high pressure electric hydraulic pump station of our factory, which can realize jacking, pushing, pulling, extrusion (up, down, left, right Direction), and other forms of operations, electro-hydraulic jacks are widely used;

3. Modification of simple presses (low or high-pressure type), bridge displacement, falling beams, replacement of rubber bearings (thin synchronous jacks), static load tests, pile foundation detection, trenchless engineering pipe jacking, large equipment jacking, factory maintenance, and other industries have been widely used.

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.

Precautions of Post-Tension Jack

1. Before using the jack, it must be timely calibrated by the legal metrological technical organization authorized by the competent department according to the requirements to determine the correction coefficient of the jack, oil pump, and oil pressure gauge. During tensioning, the jack must be installed and used in strict accordance with the oil pump number, oil gauge number, and jack number indicated on the calibration report.

2. Before tensioning, the corresponding value between the oil gauge reading and the tensioning force shall be calculated according to the correction factor formula. Re-calibration shall be conducted under the following conditions: before the first use of the new jack; When the pointer of the oil pressure gauge cannot return to zero, the jack, oil pressure gauge, and oil pipe have been replaced or repaired; When the jack is used for more than 6 months or tensioned for more than 200 times; Other abnormal phenomena occur during use.

3. When using the jack, pay attention to the stability during lifting. After lifting the heavy object slightly, check whether there is any abnormal condition. If there is no abnormal condition, continue to lift the jack.

4. When several jacks are working at the same time, it is necessary to have a specially assigned person to command, so that the lifting or lowering can be carried out synchronously. Wood blocks shall be supported between two adjacent jacks to ensure spacing to prevent sliding.