A, what is concealed engineering?

Concealed engineering refers to buildings, structures, building materials or components buried in objects during construction, which are covered and invisible. Such as housing foundation, steel bars, hydropower components, equipment foundation and other sub-projects.

Second, what are the contents of the hidden works of highway engineering?

(1) Foundation and foundation, including soil conditions, geometric dimensions, elevation and foundation treatment of trench foundation;

(2) The rebar in each part of the main structure, including the variety, specification, quantity, spacing, joint, rust removal and substitution of rebar;

(three) the diameter, position, slope, joint treatment and binding of prestressed tendons and reserved holes in bridges and other structures;

(4) On-site structural welding, including covered electrode brand (model), joint specification, weld length, height and appearance slag removal;

(five) the flatness, slope, bridge end transition slab position and size of the leveling layer under the waterproof layer of the bridge deck;

(6) Specification, quantity and embedding position of embedded parts for bridge deck expansion joints;

(7) Internal and external thermal insulation and anticorrosion of steel pipes and pipelines;

(8) Ellipticity of steel pipes with a diameter of 1200mm or more;

(9) Rainwater and sewage pipes: concealed parts of concrete pipe seats, pipe belts and ancillary structures;

(10) Thermal pipeline: pipeline insulation, trench and waterproof outside the cabinet;

(eleven) hydraulic structures and asphalt waterproof engineering, including waterproof deformation joints of each layer under the waterproof layer;

(12) communication pipeline project;

(thirteen) the size, maintenance, grade and surface elevation of steel bars for equipment foundation and cement concrete;

(14) Layout of optical cable, reserved length, physical and electrical properties of joint, excavation and backfilling of cable trench and connection of optical cable;

(15) Burying and introduction of grounding body, grounding resistance (wet and dry), rust prevention and anti-corrosion treatment of mechanical and electrical equipment support box.

Third, the completion process of concealed works

Because it is a concealed project, if there is a quality problem, it will have to be covered again, causing heavy losses such as rework. In order to avoid the waste of resources and the loss of both parties, and ensure the project quality and smooth completion, the contractor shall notify the employer to check before the concealed works are concealed, and the concealed works can be carried out only after the employer has passed the inspection. In practice, when the project is covered and concealed, the contractor should first conduct self-inspection. After passing the self-inspection, the owner or the site representative stationed by the owner shall be informed in time to check the concealed works, and participate in the operation of the concealed works before the concealed works are concealed. The notice includes the contractor's self-inspection records, hidden contents, inspection time and place. After receiving the notice, the Employer or its on-site representative shall arrive at the concealed site within the required time to check the concealed works. After passing the inspection, the employer or its representative stationed at the site shall sign the inspection record, and the contractor may carry out concealed construction only after passing the inspection. The Employer shall have the right to require the Contractor to improve the engineering conditions within a certain period of time when it finds that the concealed engineering conditions are unqualified. If the conditions of concealed works meet the requirements of the specification, and the Employer or its representative in the site refuses to sign the inspection record after inspection, it can be regarded as the employer's approval in practice, and the contractor can carry out concealed works.