How to determine the tonnage of the tension jack?
Tensioning jacks are special jacks used for tensioning prestressed tendons such as steel hinge wires. The tensioning jack needs to be used in conjunction with the tensioning oil pump, and the power for tensioning and jacking is provided by the high-pressure oil of the tensioning oil pump.
Determination method of tension jack
The tension jack is generally calculated according to a force of 20 tons, and the number of holes on the working anchor is multiplied by 2. Then add a safety factor of tens of tons. A bundle of steel strands is 19.5t. Assume that M15-19 anchors are used. , then the anchorage is 19 bundles, 19.5*19=370.5t, but there is a coefficient for the tension of the jack, and the rated tension of the tension jack is declared to be 1.5 times the required tension, and not less than 1.2 times.
Generally, the PMAX corresponding to a 100-ton jack is 60MPa, and other corresponding relationships are 150, 62.5; 200, 63; 320, 60: 600, 62. These are also in the instruction manual of the jack. The relationship between output and oil pressure is related to the effective area of the oil cylinder of the jack. You can’t simply look at the oil pressure. Various measuring instruments have certain errors, so there are instructions from the manufacturer.
Factors affecting the elongation value of the tensioning jack
1. Since the arrangement of straight lines and curves will affect the elongation value of prestressing to a certain extent, we must first know whether the prestressing tunnel is arranged in a straight line or a curve, and then make a judgment.
2. The number of stretching dry jack companies is increasing, so each company's technology is also different. The sequence of stretching is different, and the recorded forms will be different. The prestressed stretching elongation value is naturally will be different.
