Trenches for electric cables, Elements of cable racks
Application of elements of cable racks at design, construction and reconstruction of cable transitions provides:
- installation on bridges with steel concrete and metal flying structures, driving on top and low, with different designs of coastal support;
- any arrangement of a trench on the bridge in the plan and a profile;
- placement in a trench of connection sleeves and stocks of a cable;
- laying to the trench of the feeding cables and their separate placement with signal cables;
- protection against unauthorized access to cables, convenience and simplicity of service.
Cable transitions in a metal trench are located on portable brackets from a bridge outside. The design and a way of fastening of portable brackets depends on type of flying structures and coastal support of the railway bridge. Standard materials for design provide:
- the brackets fixed by means of high-strength bolts in the place of the drilled rivets to the lower belt of flying structures with driving low;
- the brackets fixed by means of bolts to racks of a perilny obstacle of coastal support and steel concrete structures with driving on top;
- the brackets fixed to sidewalls of coastal support by means of anchor bolts.
Fastening of brackets to racks of a perilny obstacle or consoles of a sidewalk flooring can be made by welding. Brackets allow to regulate height of fastening and a departure of sections of a trench out of bridge limits.
The cable rack gathers from separate sections 2,0 m long.
Sections of a cable rack gather from the bottom and a folding cover. On the basis of section guides of a mobile joint for compensation of temperature movements at joints of flying structures of the bridge are welded on.
The flying, end and widened sections of a cable rack are issued. End sections of a trench are intended for burying in soil of river banks, the widened sections - for placement of connection sleeves and stocks of a cable.
Sections of a trench are supplied with openings for a condensate drain.
The standard design decision has provided the section of a cable rack 140×200 by mm. Also trenches with the following sections are made: 140×300 mm, 140×400 mm,
200×300 mm, 200×400 mm.
The covers of sections of a trench serving for ensuring access to cables open outside. Covers of the flying and widened sections have an emphasis for fixing in open situation and are supplied with special locking devices.
For additional protection of cables against damages of section of a trench are supplied with the elastic basis from glass wool or basalt fiber.
In need of separate placement in a trench of the alarm and feeding cables, sections of a trench can be in addition supplied with dividing partitions.
Elements of cable racks have the anticorrosion coating expected operation in environmental conditions
The order of elements of cable racks is carried out according to recommendations and the table of the order.