Key Points of Quality Supervision of Hollow Anchor Bar Materials
Hollow anchor bars are generally used in railway, tunnel support, and similar projects. Compared with solid bars, hollow anchor bars have stronger shear strength. The outer surface of the hollow anchor bar is threaded throughout the body, which increases the bonding area between the anchor rod body and the rock and soil compared with the smooth rod body, thus enhancing the anchoring force. However, there are some problems with the raw materials and re-inspection of the hollow anchor bars used in some projects at present, and there is a lack of quality control of the raw materials of the hollow anchor bars in the quality supervision process.
Key Points of Quality Supervision of Hollow Anchor Raw Materials
First of all, check whether the hollow anchor bar used in the project has a quality guarantee that meets the requirements. The warranty is a product certification document provided by the manufacturer to prove whether the product is qualified.
Check whether the content of the warranty is consistent with the design drawings: whether the standard of the raw material of the hollow anchor bar designed on the drawing is consistent with the quality assurance document; whether the designation, specification, yield strength, ultimate strength and other indicators of the hollow anchor bars designed on the drawing are consistent with the quality assurance document. If the value does not match, it means that the material of the hollow anchor bar does not match the design and cannot be used in construction.
Sampling re-inspection should be carried out on the raw materials of anchor bars in the project site. It can be used only after passing the re-inspection. If the re-inspection fails, double-sample re-inspection can be carried out following the requirements of the standard specification. Resolutely put an end to the use of unqualified materials. If unqualified materials are used in the project, the structural performance of the project can only be downgraded after the design check and calculation or reinforced, or the part of the unqualified materials used in the project can be removed.
The raw materials used on the project site should be randomly inspected according to the inspection batches required by the standard specifications to prevent missed or under-inspected phenomena. Sampling testing should be carried out on suspicious or controversial materials during use to ensure that materials used in the project are monitored around the clock.
The authenticity of the material testing process should be supervised. Raw materials should be submitted for inspection under the witness of supervisory representatives throughout the process to prevent the sample sender from replacing the sample during the sample delivery process; the testing agency should be a third-party testing agency that has passed the national certification.
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