Hengshui Kaixiang Rubber Products Co., Ltd.

Preparation work: The heading diameter of the steel wire is m. Test results: The heading strength is ~% of the actual base metal strength, and the damaged part is at the base metal.
The geometric dimensions and hardness of the heading anchorage are fully in compliance with the requirements of specification B after inspection.
Test device and process
The prestressed steel wire bundles and anchors used for the test are assembled according to the actual application status. The free length of the prestressed steel wire in the specimen is taken.
Before the test, secure the steel wire bundle heading anchor assembly in place. Directly use a synchronous hydraulic jack to load the heading anchor, and load it in four stages to % of the standard tensile strength of the prestressed steel wire, then hold the load h, and then load again until failure. To break its load elongation curve.
Steel wire force uniformity test test method
Paste a certain number of resistors on the outer and inner rings of the steel wire bundle, generally not less than % of the total number of steel wires. The resistor is generally arranged at one end of the steel wire bundle. During the test, the tension ends are alternately placed at both ends, and the stress of the steel wire at the tension end and the fixed end is measured respectively. Combining engineering practice and laboratory research, the measurement results of different types of straight beams and curved beams are shown in the table.
Steel strand cutting and threading
The steel strands used for QM anchors do not need to be cut to equal lengths. They can be estimated based on the net length of the component hole and the required working length of the anchor and jack. It is advisable to use a fast
sheet grinder to cut the steel strand to ensure that the cut is smooth and the wire ends are not scattered. In actual projects, manual threading is used. In order to reduce the threading resistance, a guide cap can be placed on the end of the steel strand. When encountering multi-span or difficult curves, a beam-piercing machine or winch can be used to speed up the progress and reduce labor intensity.
Steel strand tensioning
Before installing the QM anchor, the steel strands, anchor plate holes, clips, etc. should be cleaned. When installing the anchor, you should first install the working anchor plate on the steel strand, push it to the trumpet-shaped pad surface, align it with the circular stop on the pad, and insert the clips into the steel strand one by one. , push it into the tapered hole of the anchor plate, and use the casing to tighten until the anchor plate enters the seam of the backing plate and the exposed clips on the anchor plate are flush.
In addition to taking the tensile force according to the design value during construction, the friction loss caused by the edges and corners of the steel strands at the entrance of the pad and anchor plate should also be considered
When the steel strands are anchored, the anchors are exposed The length of the clip and the shrinkage value of the anchor can be controlled by a suitable limit plate. The shrinkage value of the anchor in the actual project is ~m
, which is smaller than the expected value (mm).
Cut off the excess steel strand before wrapping the anchor head, but the exposed length of the anchor's outer steel strand should not be less than m, and the thickness of the concrete protective layer at the end of the steel strand should be ensured
not less than m.
1. The design requirements of connectors and anchors must meet the matching accuracy requirements with steel bars.
The yield load and failure load shall not be less than the yield load and failure load of the steel bars, and there should be a certain reserve.
The length of connectors and anchors must not only meet the shear resistance requirements of the threads, but also the threads must not undergo excessive deformation during tensioning and anchoring.
The maximum outer diameter of the connector should meet the requirements of the reserved hole diameter as much as possible.
Material Selection
The selected materials should meet the load-bearing requirements of connectors and anchors, and should also have good craftsmanship and economy.
In order to understand the stress distribution of each section of the connector under tension, a stress distribution test was conducted. Tests show that the maximum stress section is located in the middle third of the connector, and then decreases linearly toward both ends, so the connector is designed to have a variable cross-section.
The maximum outer diameter of the connector is designed to be greater than the failure load of the steel bar and to allow it to have a certain reserve capacity. The minimum diameter of the end is designed with reference to the stress distribution curve of the cross-section and determined through physical damage tests. If the end section is too small, although it can still meet the tensile requirements, due to insufficient stiffness, the end will become oval under the action of tension, which will cause the steel bar to slip from the connector.
Hengshui Kaixiang Rubber Products Co., Ltd.
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Contact person: Manager Hou
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Address: Beitian Village, Pengdu Township, Binhu New District, Hengshui, Hebei Province