Tunnel support system

Cable Ladder type TOE 

TOE is a cable ladder system suitable for long support spacing, for heavy loads and where vibration can occur. The cable ladder system is typically used for supporting cabling for HVAC, lighting, surveillance, radio, communications and signage. The TOE system is suitable for use in a variety of infrastructure environments including land and subsea tunnels. The rungs of this cable ladder system are particularly strong, and the system has support spacing typically ranging from 3 to 6 m. It is complemented by a wide range of accessories including expansion splices, radio wire holders and lighting accessories to name just a few.

Central Support in Tunnels

We offer specific solutions for both concrete culverts, entry zones and exit zones. Our solutions include consoles for fixing from rock bolts, threaded rods and in precast sections and deliver the possibility to adjust 20 mm sideways (to adapt for unaligned bolts) and 60 mm height adjustment. The construction height below the cable ladder is maximum 10 mm with our solutions which is far below the maximum 50 mm set by the Norwegian Public Roads administration technical handbook. Our consoles for central support in tunnels makes it especially simple to install light fixtures, as you can slide the fixture over the console.

Solutions for unaligned Rock Bolts

Unaligned rock bolts in tunnels is a common issue. If the rock bolts are not installed within the tolerance requirements (+ /- 20 mm), it can be a time-consuming and often extremely challenging task to align the rock bolt. We have suitable equipment to simplify the assembly without removing and repositioning the rock bolt. We offer both plates for offsetting and brackets to align the bolts.

Stabilization of Cable Ladders

There is no simple answer for when cable ladders require bracing, however we have broad and long experience in this area, and are able to recommend considering bracing in entry zones, when there is long pendular channels, uneven loading or long distance to the ground. This also applies when camera surveillance is installed directly onto the cable ladders, because it will be sensitive to vibration.

When installing bracing it is also important to consider expansion. The bracing must be designed to allow for the expansion and contraction which occurs in the installation due to temperature variations.

Expansion Splice Connector

We offer splice connectors with an expansion zone for attaching long rungs of TOE/LOE ladders together. The expansion zone prevents deformation of the cable ladder due to expansion and contraction due to temperature variations. We also offer bonding jumpers at expansion splices.

To ensure proper installation, we have developed a calculation program to give guidance on where and how many expansion joints are required based on the various factors of the installation including the temperatures for installation and operation. 

Fitting and Equipment Plates

We offer a range of fitting and equipment plates for radio signal cables, junction boxes, signage boxes, light fixtures, detectors and other equipment. We have a wide range of standard products to cover all project needs, and we can also offer customized solutions to suit special project requirements.

Fireproof cable protection for tunnel rehabilitation

When older tunnels are rehabilitated, extra fire ventilation and surveillance equipment are often installed. The cabling is then exposed and challenges with fireproofing these cables behind the vault often occurs.

To solve this problem, we have developed a firebox that fits on the cable ladder where these cables are situated. The firebox is isolated with a flame-retardant material that protects the cables in case of a fire. The temperature increase in the protected zone is also reduced to ensure the operation of critical equipment such as fans and emergency lights until the tunnel is evacuated.

Please contact us to discuss the right solution for your project.