Emtelle Power Protect+ HV Cable ducts chosen to carry 132kV, 33kV, 11kV, pilot and telecomm cables across the new White Rose Bridge Crossing, Doncaster
Project: White Rose Railway Crossing. The A 6182 Improvement Scheme.
Client: Doncaster Municipal Borough Council.
Contractor: Balfour Beatty Civil Engineering Ltd.
Bridge Length: 184 metres span, total ducted section 220 metres.
Special considerations: uPVC HV Cable ducts will expand 7 times that of steel per degree centigrade. The temperature range is from -10 degree Celsius low winter to + 75 degree Celsius maximum cable operating temperature.
Virgin polymer solid wall uPVC ducts to ENATS 12/24 (2008).
- 160mm x 6mtr Class 1 duct with taper socket push-fit joints. (450N Compression @ 75 degree Celsius)
- 125mm x 6mtr Class 1 duct with taper socket push-fit joints. (450N Compression @ 75 degree Celsius)
- 5mm x 6mtr Class 2 duct with taper socket push-fit joints. (450N Compression @ 50 degree Celsius)
- 160mm x 600mm Rotek Expansion Couplings.
- 125mm x 600mm Extruded Expansion Sleeves
- 5mm x 600mm Fabricated Expansion Units.
To cope with the temperature range of 85 degree Celsius and the expected1.3 metres of thermal movement, the ducts were solvent welded together into continuous ‘rods’ of duct between expansion units.
This method was chosen owing to the controllability of the expected expansion and contraction without ‘shunting’ out of seal-ring joints.
To maintain duct directional stability, the ducts were loosely clipped in place with the ‘Band-it’ stainless steel strapping which allows the duct to expand and contract but restraining the ducts in the event of cable spasm.
At mid-point between expansion units, the ducts were anchored directly to the Speedwell ‘Unitrunk Ladder system of continuous support framework’
This-in-turn is directly fixed to the main bridge steelwork.
This then controls the direction of any differential thermal movement either side of the anchor point towards the carefully sited expansion units.
The 132kV, 33kV and 11kV cables are carried inside 160mm Emtelle Class 1 Power-Protect+ ducts to ENATS 12-24 (2008).
The thermal movement is absorbed by the 160mm ‘Rotek’ ‘O’ ring seal expansion units.
The Pilot cables are housed inside 125mm Class 1 ducts. The thermal movement is absorbed by 125mm expansion sleeves.
The DTS and fibre telecom cables are housed inside 96.5mm Class 2 ducts. The thermal
movement is absorbed by fabricated 96.5mm expansion sleeves.
Also visible are the expansion units anchoring brackets, holding these expansion units and sleeves firmly in place. The solvent welded ducts being free to expand and contract into these units.
The ducts are now installed inside the duct area of the bridge section.
This particular 84 metre section is the central northern span of the bridge over the railway line.
This area will be covered by steel sheeting and then this section will be craned by a 1,200 tonne crane to the installation site some 300 metres south west of the assembly site where eventually the road finish will be laid.
The duct sections will be solvent welded to the 2 x 50 metre previous craned sections prior to cabling.
Emtelle UK Ltd personnel were present at the design stage, on site to give instruction by demonstration in-situ and to ensure that the installation was as required by the Specification.
After a long wait for a rail closure permit and ideal wind free weather conditions, the bridge sections were craned into position and the cable duct jointed with anchored sliding seal connectors.
Since that time, the carriageway sections have been covered and the road surface applied. The White Rose Way Bridge road now takes traffic whilst providing a safe cable path for the HV cables and other services within its core.
For more information:
Please contact Andy Martin. UK Power Sales Manager. Emtelle UK Limited.
Phone: 07979 538967 E-mail: firstname.lastname@example.org