Handan Zhongfu Industrial And Mining Accessories Co., Ltd.
Handan ZhongFu company is a professional manufacturer for underground mining supporting products with over ten year experience. We can manufacture Split sets ,friction bolt, Combi split sets, Expandable friction bolt,Swellex, Threaded bar bolt, Cable bolt, Combi cable bolt, Welded mesh, Domed plate, Nuts, other mining Equipment.
The safety matters of pre-stressing wedge and barrel：
(1) The cutting of prestressing tendons shall be done by grinding wheel saw, and electric arc cutting shall not be used;
(2) The stranded wires shall be straightened out one by one and bundled into bundles without any disorder when making up the bundles. Extruded anchorage or embossed anchorage at the fixed end of the strand should be assembled with the bearing plate and spiral tendon beforehand;
(3) The machinery and equipment and instrumentation used for applying prestressing force should be maintained and calibrated on a regular basis.
(4) Before the prestressing tendon is tensioned, the report of the test pressure for the strength of the concrete should be provided. When the compressive strength of concrete meets the design requirements and is not less than 75% of the design strength grade, prestressing force can be applied; (5) Before tensioning the prestressing tendons, the surface of the bearing plate should be cleaned up and the quality of the concrete behind the bearing plate should be checked. If there is a cavity in the concrete, it should be repaired with epoxy mortar before tensioning;
(6) When the anchorage is installed, the anchor plate should be positive, the clamping piece should be tightened, and the piece position should be even: however, it should not be hit too hard when tightening the clamping piece, so as not to knock the clamping piece out of shape;
(7) Before the formal tensioning of large tonnage pre-stressing tendons, it should be test-tensioned together with the professional personnel. Confirm that the tensioning process is reasonable, the tensioning elongation value is normal, and no harmful cracks appear before batch tensioning, and if necessary, determine the actual hole loss, the curve of the prestressing beam shall not use a small jack single tensioning; so as not to cause unnecessary loss of prestressing force. During tensioning, the operator must stand in the safety zone and take protective measures, and note that the operator is strictly prohibited to stand at the front end of the prestressing tendon during tensioning and tensioning:
(8) When the prestressing tendon is tensioned, it should be loaded from zero to the initial tension at the starting point of the measured elongation value first, and then loaded to the required tension in a graded manner,
(9) Tensioning of prestressing tendon is managed to take the stress control, and elongation is calibrated. The permissible deviation between the actual elongation value and the calculated elongation value is -5%+10%. If the value exceeds the value, tensioning should be suspended; measures to be adjusted before continuing to tension; such as elongation value is small, can be taken to overtensioning measures but the tension limit shall not be greater than 0.8fptk value; in the multi-wave curve prestressing tendons, in order to improve the tension stress at the inner support, reduce the tension stress at the lower mouth of the anchorage after tensioning, can be taken to overtension back to relaxation technology;
(10) Orifice grouting requirements are dense, cement paste Strength grade should not be less than C30, the aperture should be wet and clean before grouting, and the grouting should be carried out slowly and evenly without interruption, and it should be ventilated and smooth. If the borehole is blocked, the grouting port must be replaced, but the cement slurry must be discharged for the first time, so as to avoid the existence of gas between the two grouts. After filling the hole and closing the exhaust hole, it is appropriate to continue to pressurize to 0.5-0.6Mpa, and then close the grouting hole later. The grouting pressure of vertical orifices shall be determined according to the grouting height.
(11) The grouting of orifices with connectors connecting multiple spans of continuous prestressing tendons shall be grouted after tensioning one span and then grouting another span, and shall not be grouted at one time after all the spans have been tensioned.
(12) The length of the exposed length of the prestressing tendons after anchoring shall not be less than 30mm, and the anchorage shall be protected by sealing end concrete. When long-term exposure should take measures to prevent corrosion; when the strand has floating rust, please anchor the clamping section and the outer end of the strand floating rust and dirt clean, so as not to install and tension floating rust, dirt filled with clip sheet red slot and caused by slippery wire;
(13) The tool clip for the three-piece type, the work clip for the two, the two can not be used as a mix. Work anchor can not be used as a tool anchor can not be reused;
(14) Anchor should be properly stored, the use of rust, water and other debris shall not be stained. Work clip can be used by removing the foam in the box, but when the pre-stressing beam is long and must be repeatedly tensioned and anchored, it is recommended to apply a small amount of lubricant (such as retreating anchor spirit) in the tapered hole of the anchor plate, which is conducive to the work of the clip to follow up and retreat the anchor but also conducive to the anchorage of the anchorage for a number of times; the outer surface of the tool clip and the inner surface of the tapered hole of the anchor plate is coated with lubricant before use, and often remove debris on the surface of the clip to make the retreat flexible, but when the clip is open or tooth surface destruction, it is not allowed to have rust, water and contamination of other sundry matters. But when the clip sheet open intense or tooth surface damage is snow replacement, shall not be used again:
(15) tensioning should be safety measures, tensioning jacks can not stand after people:
(16) anchoring system should be used in conjunction with, can not be mixed with other systems. If you want to do static load test, please use organic solvent (e.g. gasoline) to clean the clamping piece and wipe the rust-proof oil of the anchor plate hole clean, otherwise it will affect the anchorage performance;
(17) Prestressing construction should be carried out by a professional construction team, and the construction personnel should be professionally trained and licensed.
Our address
West Side Of Jianshe Street, Southwest Industrial Zone, Linmingguan Town, Handan, Hebei, China
Phone Number
+8615830050566
zfgongkuang@aliyun.com
