Cable Overpasses

**CABLE TRESTLES**

A **cable trestle** is a special engineering structure, featuring a long-span design, intended for the open laying of cable communications on the territory of industrial, metallurgical, or oil refining enterprises. Its purpose is to optimally utilize overhead space and to be used in cases where excavation work is not feasible.

**Cable line trestles** are distinguished as either **pass-through (walk-through)** or **non-pass-through (non-walk-through)** types. Each of these, according to the **PUE (Electrical Installation Code)**, is designed for laying more than twenty conditional cables.

• **Non-pass-through cable trestles**, constructed from reinforced concrete and rolled steel, can only be serviced by personnel using special vehicles or cranes due to the lack of access to cable communications within the structure itself.

• **Pass-through trestles**, which have reinforced concrete, metal, or combined structures, are serviced from special platforms or gangways that are elements of the structure itself. A fully or partially enclosed long-span pass-through structure is called a **cable gallery**.

**TYPES OF METAL STRUCTURE CONNECTIONS**

**Cable trestles** are above-ground metal structures used for securing cables, including power cables, above the ground. Most often, such structures are used at industrial facilities where underground channels are difficult or impossible to construct, or where they are already occupied by other utilities. Furthermore, this method of cable laying avoids the negative effects of chemical compounds contained in the soil and significantly simplifies the process of inspecting cable conditions, their repair, and replacement.

Since any industrial enterprise uses a large number of pieces of equipment, a cable trestle must be able to withstand a significant weight and volume of networks, be resistant to wind and snow, and withstand the negative effects of atmospheric precipitation without losing its characteristics, partly due to the presence of special anti-corrosion coatings.

**Cable trestles** can be **technological** or **special**. Technological trestles are structures used not only for laying cables themselves but also for securing other equipment. Special structures are used exclusively for cable installation.

The **design of a cable trestle** may imply that in the future the structure will be used for two-sided or one-sided cable laying. Two-sided products are more expensive structures but quickly justify the investment due to their capacity for securing a larger number of cables (up to 60 units).

**Non-pass-through and pass-through cable trestles** are also distinguished. Pass-through trestles are equipped with special gangways for cable maintenance. Non-pass-through trestles are serviced by means of special mechanisms.

**Installation of cable trestles** is most often carried out on a foundation made using screw piles, or on a reinforced concrete foundation. Such structures are delivered to the installation site in a disassembled form, which significantly simplifies and reduces the cost of their transportation.

Required data for making an inquiry:

• total route length;

• required laying height above ground;

• required column spacing;

• cable load in kg/m;

• number of crossings over roads, their height and length;

• installation area of the trestle for calculating snow and wind loads;

• general laying plan indicating turns, branches, and crossings;

• cross-sections indicating cable trays, quantity, and types of laid cable.