Take a tour of the Elizabeth line’s new stations, art & public space this summer
In 2012 RIBA launched a competition to design a new pylon structure for the UK. The existing design has not changed since 1927 and they asked that the designs explore the relationship between our energy infrastructure and the relationship between our energy infrastructure and the environment within which it needs to be located, producing highly innovative and imaginative solutions that also respond to the exacting technical requirements.
We have concentrated on investigating how we could work with readily available materials and construction methods and create a structure that could be sympathetically integrated into the environment. The form is dynamic; a simple sculptural statement. Primary steelwork expresses the function and a secondary layer of structural mesh creates pattern and texture. The main visual mass is centred on the core with a deliberate lightness of structure for the suspension elements. The use of materials and finishes has been selected to ensure that the design can be manufactured and constructed on site with the greatest of simplicity.
The pylon is in the geometric form of a twisted helix, comprising of warped modules that stack together to achieve the required height. Each module is constructed from 250×250 SHS with rigid connections which bolt together on site to provide structural continuity. The suspension arms are constructed from 219Ø CHS and are held in position by three tie rods pinned back to the corner points of the modules. Lateral stability for the pylon is provided by both the rigidity of the modules and from the continuous steel mesh that follows a single surface from the base to the top of the pylon.
The design’s modular construction allows variations in height that can be assembled in different configurations to suit local conditions. We have designed an option for integrating a wind turbine within the structural core and this is detailed in the design report.
The construction of the pylon utilises bolted and pin connections, which enables parts to be easily replaced on site. Service operatives can climb the lattice structure and work on one side at a time as specified in the brief.
The pylon design utilises readily available materials and manufacturing which can be produced by a number of steel fabricators thereby reducing the capital cost. After its design life of 80 years the modular and bolted structure can be easily decommissioned with minimal specialised equipment and all steelwork and components recycled.