RAY HOLE ARCHITECTS
SNOWDONIA NATIONAL PARK AUTHORITY
Hafod Eryri is a single storey braced steel frame located on the summit of Snowdon which replaces the original building constructed in the 1930s. The adoption of a steel frame enabled the client to change the design radically from the original concept, allowing the building to be opened up so that the view from the summit could be fully appreciated.
A major benefit of using steel for this project was the fact that it is lighter to transport than precast concrete, as all materials had to taken up to the summit by train. Transporting over 100 tonnes of steel and more than 2,500 bolts up the mountainside was never going to be an easy feat – everything had to fit on a 11m long x 2.5m wide bespoke flat bed truck. All the parts of the steel frame had to be precisely numbered, distributed in numerical order and each phase was colour coded, so that they would reach the summit in the correct order ready for unloading and construction.
Design was undertaken to withstand the onerous applied loads and constraints such as:
- 150mph winds
- 5m high snowdrifts
- freezing temperatures (in winter temperatures can reach -40°C – galvanized steel is durable even at these temperatures)
- heavy roof cladding (there is approximately 90 tonnes of granite slabs on the roof)
- deep roof build-up reduced the maximum depth of the 13m long beams
The main café area does not have a vertical column, most are raked in both planes to create the complicated shape. Roof beams over the main café also had to be tapered at the ends to suit the ceiling. Services zones were provided to avoid passing services through the beams which were already working hard.
The visual aspect of the exposed steelwork determined the choice of material – stainless steel CHS columns were used in the glazed areas. The isolation of the stainless and mild steels was essential even at complicated junctions where large forces had to be transferred from one member to another.
Fabrication, erection and on-site checking was made easier due to the trial assembly which also assisted the design of the other items, such as cladding, windows and the roofing system etc. A trial construction of the frame was carried out offsite before being galvanized to ensure that the plant and machinery were suitable, and that the phasing would work due to the unusual shape of the building. Everything was also checked for fit before going to site.
In terms of its environmental impact, the building is clad with granite and the whole roof is covered in granite slabs. This helps the building blend in with its environment, plus its weight also keeps the building from blowing away. The outer cloaking is designed to be all self-finished where possible. The majority of the steelwork is galvanized to ensure the durability of the steel frame. Where the steelwork is exposed, it is stainless and has been given the ceramic ball blast treatment to give it a high quality finish.
Hafod Eryri has been designed to be inherently a non-combustible building as evacuating the building would be more dangerous, due its location, than staying inside.
Rarely can a site and logistics be more challenging than this. The largely granite cladding and roof required a heavy steel frame, carefully modularised for tightly planned transport to the summit on the narrow-gauge railway.
It all worked well in very tough conditions – a meritorious effort by all the team.