Selection of horizontal bends for bridges
    1 In the engineering design, the horizontal bending of the bridge, the layout of polymer cable trays should be based on economic rationality, technical feasibility, operational safety and other factors. Compare and determine the solution, but also fully meet the requirements of construction, maintenance, repair and cable laying.
    2. When the cable tray is laid horizontally, the height from the ground is generally not less than 2. 5m. When laying vertically, the part below the ground of 1.8m should be protected by metal cover, but it is laid in Except when in an electrical dedicated room. The cable tray is laid horizontally on the equipment mezzanine or the upper man's road and is less than 2.5m. Protective grounding measures should be taken.
    3. Cable trays, trunkings and their hangers are used in corrosive environments and should be made of corrosion-resistant rigid materials. Or take anti-corrosion treatment, anti-corrosion treatment should meet the requirements of engineering environment and durability. For places where corrosion resistance is required or where cleaning is required, aluminum alloy cable trays should be used. 4. Cable trays in the section with fire protection requirements, bridges, can be added to the cable ladders, trays with refractory or flame retardant properties, nets and other materials constitute closed or half Closed structure, and measures such as applying fireproof coating on the surface of the bridge and its support and hanger. Its overall fire resistance should meet the requirements of relevant national standards or standards. In places where engineering fire protection requirements are high. It is not advisable to use aluminum alloy cable trays.
    5. Cable lines that need to shield electromagnetic interference. Or protective external shadows such as outdoor sunshine, bridge reducer joints, oil, corrosive liquids, flammable dust and other environmental requirements. A non-porous tray cable tray should be used.
    6. In places where dust is easy to accumulate, the cable tray should be covered with a cover; cross the road section in public passage or outdoor. A pad or a non-porous tray should be used on the bottom bridge.