What are the cable ditch cover plate materials?
1. There are many kinds of materials for cable ditch cover plate: steel fiber concrete, composite resin, regeneration of resin, polymer-based composite materials, etc.
1. Steel fiber reinforced concrete:
Steel fiber is bulky and inconvenient to construct or maintain, but the price is the cheapest.
2. Regeneration of resin and polymer-based composites:
Poor temperature resistance, fragile in winter, easy to expand in summer, poor application effect, short service life and higher price than steel fiber concrete.
3. Composite resin material:
That is to say, BMC is mainly composed of unsaturated resin, chopped glass fiber, filament, some fillers and reinforced skeleton. The product has stable performance, strong temperature resistance, acid and alkali resistance, compression resistance, bending resistance, impact resistance and flame retardancy. The price is relatively higher than that of steel fiber reinforced concrete, regeneration of resin and polymer-based composites, but it is more cost-effective in terms of service life and product performance.
Second, it is divided into ordinary cement cable ditch cover plate, composite cable ditch cover plate and glass fiber reinforced plastic cable ditch cover plate according to different materials.
Among them, composite cable ditch cover plate is widely used, based on cement, supplemented by fine orthopedics, glass fiber, ore and modifier, to solve some application deficiencies of cement products. It has the characteristics of light weight, high strength, long service life and easy operation and construction. This material has been certified by the Science and Technology Department of the Ministry of Railways, and it is recommended to be used in railway ancillary construction. After years of accumulation, the ancillary structures made of this material have been successfully applied to key projects such as passenger dedicated lines and urban traffic.
According to the use characteristics of ditch cover plate cable products, new high-end composite materials are widely used in the world, and the reinforced thermosetting composite cable ditch cover plate is developed and produced, which completely overcomes many defects of other cover plates. Products can be applied to different regions, different conditions and different development needs, with good corrosion resistance, flame retardancy, high strength and simple installation. As an auxiliary facility of urban cable trench, the cable ditch cover plate material has been made of cast iron and cement for a long time. Affect the safety of use, short service life.
Available range
Manufacture and installation of concrete cover plate for cable trench and other passages in substation engineering
process flow
Construction preparation angle steel skeleton production angle steel skeleton galvanized steel bar production installation concrete pouring maintenance cover plate installation quality inspection and evaluation
Description of process flow and main quality control points:
Construction preparation (1) Material preparation: sand and stone should have re-inspection report, and cement should have factory certificate and re-inspection report; The reinforcement shall be inspected for appearance and data (quality certificate) and passed the second interview after the sample is submitted; Angle steel should have a certificate of approval, appearance inspection should be carried out when entering the site, no deformation and warping phenomenon, specifications, models and wall thickness should meet the design requirements. Covered electrode should have a certificate of approval, and the welder should have a job certificate.
(2) Preparation of prefabrication site: The prefabrication site shall be located in the substation area that does not affect the construction site, and the site size shall be determined according to the prefabrication quantity and service time. The surface of the site should be calendered, and the calendered surface should be flat, smooth and solid (cable ditch cover plate production site
(3) Technical preparation: 1) Drawing review: Do a good job in drawing review in strict accordance with the requirements of State Grid Corporation's Guidelines for Construction Technology Management of Electric Power Construction Projects (hereinafter referred to as the Guidelines). 2) Technical disclosure: Technical disclosure shall be made for all subdivisional works according to the guidelines. The content of technical disclosure should be substantive, targeted and instructive, and all personnel involved in the construction should participate in the disclosure and sign it to form a written disclosure record.
According to the pay-off size of the angle iron frame, the angle iron will be cut by a special person, the two ends of the angle iron will be cut at 45 degrees, and the angle iron frame will be welded at 45 degrees. There should be no overheating, undercut and slag inclusion when welding the angle iron frame. When welding, in order to ensure the unity of the size and deformation of the angle iron frame, a flat steel plate can be placed at the bottom of the frame, and the wire is stretched on the steel plate, and the angle steel is used to weld the angle iron frame model around. When welding, put the angle iron into the model for welding. In order to ensure that the concrete in the frame is firmly bonded with the galvanized frame, several threaded steel bars can be welded on the inside of the frame. After the frame is welded, it will be sent to the galvanizing plant for hot galvanizing treatment. The frame is easy to deform after zinc plating. Before pouring, it should be corrected to make the diagonal, flatness and size of the frame meet the requirements.
Fabrication and installation of steel bars
According to the requirements of the drawings, steel bars, hook I-beams, steel bar nodes are all bound with lead wires, and the steel bars reserved for mesh bars and angle steel frames should also be bound.
Concrete pouring: the angle steel frame is horizontally placed on the prefabrication site, and the bottom of the frame is paved with 3mm thick rubber skin to ensure that the bottom of the molded cover plate does not leak slurry, and the bottom surface is flat and smooth, and the concrete at the bottom is not higher than the angle steel frame.
In order to ensure the uniform color of the surface of the concrete protective layer, the concrete raw materials shall enter the site once as far as possible and be stacked separately. The concrete raw materials shall be measured by special personnel and evenly mixed.
Spread a layer of concrete in the angle steel formwork, vibrate it with a flat vibrator (small flat plate) for compaction, put the steel mesh into the formwork, then add the concrete to spread the angle steel cover plate, and vibrate it with a flat vibrator for compaction until the surface is radiant with protoplasm. Before the final set of concrete, the calender shall be not less than 3 times. After calendering, there shall be no scratches on the surface, and pits and sand holes are strictly prohibited. After pouring, remove the concrete and mortar around the frame.
Maintenance:
At room temperature, after concrete cover plate is poured 12h, the surface is covered with film, and it is watered and maintained for not less than 7d.
Installation of cover plate: the direction of cover plate should be considered during transportation, and the cover plate is easy to break due to reverse force. Put the cover plate on the cable trench, and use theodolite at both ends of the cable trench to fix points every 20 meters. Pull the cable to adjust the straightness and flatness of the cover plate. 3mm thick rubber pad is placed at the bottom of the cover plate resting point to adjust the stability and surface flatness of the cover plate.
Quality acceptance:
Quality inspection and evaluation shall be carried out in accordance with the relevant clauses in Code for Acceptance and Evaluation of Construction Quality of Electric Power Construction Projects Part 1 Part: Civil Engineering DL/T52 10. 1-2005. The main quality standards are:
◆ Steel frame with channel steel cover plate: the length deviation is 3mm；; Width deviation is 3 mm; Diagonal difference ≤3mm.
◆ Channel cover plate: the length deviation is 5mm；; Width deviation plus or minus 5 mm; Thickness deviation is 3 mm; Diagonal deviation ≤ 5 mm; Surface flatness deviation ≤ 5mm.