Steel strand tensioning anchorage is a very common material in pre-stressing anchorage system, which is often written as YJM/YM15-N, YJM/YM13-N in engineering terminology, where Y is usually understood as round anchor, which is also one of the meanings of tensioning anchorage; M represents the anchorage; 15/13 represents the steel strand; and N represents the number of holes of the anchor. For example, YM15-3 is a 3-hole anchorage with 15.24mm steel strand. Next, let's talk about one of the features of the steel strand anchorage: tensioning, and its precautions.
(1). Anchorage should be properly stored and applied without embroidery, water and other dirt; No current diversion. Before installation of anchorage, please remove the floating rust and dirt from the steel strand to avoid slippage caused by floating rust and dirt filling the teeth groove of the clamp during tensioning.
(2). Please strictly verify the strength and diameter of the steel strand, which cannot be used for tensioning and anchoring when it is corroded. Please check whether there is any leakage of bonded pre-stressing tendons in the pre-stressing orifice before installing anchor plate, if there is, it should be cleaned up.
(3). The clamp can be installed into the anchor plate to fasten the steel strand when removing the package. When the pre-stressing bundle is long (more than 36 meters) or the single bundle is more than 12 steel strands, a few lubricants (such as anchor withdrawing oil) should be applied to the tapered hole of the anchor plate to facilitate the follow up, withdrawal and anchoring of the clamping piece to avoid wire breakage.
(4). When installing the anchor, the anchor plate should be aligned with the gasket stop; the clamp should be flush after installation, and lightly knocked with a special object if necessary, but do not damage the clamp by heavy knocking.
(5). When tensioning for construction, it is necessary to match the corresponding limit plate and stuff anchor according to the standard of work anchor.
(6). During the period from the application of pre-stressing force to the encapsulation after anchoring, the operator shall not move in front of the anchor, and shall not hit the steel strand or the anchor hard unless a useful shielding method is adopted; when removing the excess steel strand, ensure that the anchor is not affected by the cutting heat, it is recommended to cut it with abrasive wheels, and it is prohibited to cut it with welding and oxygen.
(7). Before sampling static load test, the user should wipe the clamp and anchor plate hole clean, and the clamp device should be symmetrical and flush, otherwise it will have an effect on the function of static load test.
(8). The anchor material has a great influence on the anchor clip, that is, even for the same steel number and production manufacturers, if raw materials are different, it would be very different, and may lead to the unstable quality of anchor production. The technical content of anchorage is very high, and the producer must be qualified. The standards, scales and technical parameters of different types of pre-stressing anchorages, such as the way, scale, point of view and tooth shape of the clips are determined by the planning, which can’t be produced randomly as it requires high techniques. It is necessary to process in accordance with the planning diagram and there must be qualification for the manufacturing of the anchor.