Hafod Eryri - Snowdon Summit Building

Description – single storey braced steel frame located on the summit of Snowdon to replace original building constructed in the 1930s.

Evadx were proud to have been chosen as the main steelwork contractor of the summit building which was modelled and detailed on StruCAD, each phase of the project was subsequently fabricated at our premises in North Wales. Transporting over 100 tonnes of steel and more than 2,500 bolts up the mountainside was never going to be an easy feat and was mad a lot more difficult by freak June rainfall. A trial construction of the frame was carried out at the Corus site at Deeside before the frame was galvanised to ensure the plant and machinery were suitable and the phasing would work due to the unusual shape.

Planning and architecture.

The new Snowdon Summit Building, Hafod Eryi was designed by Ray Hole Architects for Snowdonia National Parks Authority with Carillion as the Main Contractor. Hafod Eryi was the name given to the building, (“Eryri” is the Welsh name for the mountain and “Hafod” means “a dwelling on high land”). The client had expected a more cave like experience inside the structure, as they had mainly considered a traditional form of construction using masonry and concrete. This was at a very early stage, before they fully considered the use of a steel frame, and was governed by the size and weight of materials that could be taken to site by train. The adoption of a steel frame enabled them to change the design radically and open up the building so that the view from the summit could be fully appreciated. In terms of its environmental impact, the building is clad in granite and the steel frame is strong enough to support a whole roof covering of granite slabs. This helps the building blend in with its environment, in that anything other than a rock finish would look out of place. Its weight also keeps the building from blowing away. The curved and organic shape of the building is architecturally very pleasing, and again, aided the 3D model of the steelwork, it is the frame beneath the finish that allows this to happen. The outer cloaking is designed to be all self finished where possible. When it came to anything on the outside of the building, the client would say “would you do that on a Pyramid?”. So it was no to paint, no to render, no to letterboxes! Etc Where the steelwork is exposed, it is stainless and has been given the ceramic ball blast treatment to give it a high quality finish. The building is very efficient and as self reliant as possible. It got a Very Good BREEAM rating.Energy conservation is aided by CHP Generators, maximizing solar gain to the South elevation, and rainwater harvesting.

Benefits achieved by using steel construction

  • Recyclable – can be demounted at the end of the design life and reused
  • Strength: gives good strength and stiffness to resist the extreme conditions
  • Lighter to transport than precast concrete: all materials had to shipped via the mountain railway which had limited capacity (length of load , weight, number of trips)
  • Straightforward to maintain: in winter there is no heating and temperatures can reach -40°C. Galvanised steel is durable even at these temperatures
  • Flexibility: the building had a trial assembly and at this relatively late stage several connections were able to be welded up to reduce the number of elements to be transported
  • Speed of erection
  • Size of elements: steel is stiffer than concrete or timber, so element dimensions were minimised
  • Reinforced insitu concrete had to be minimised as transport was an issue (segregation on the train, setting issues). Precast concrete elements were limited due to weight issues.

Efficiency of design, fabrication and erection

  • 3-D CAD used by Architect, Engineer, Steelwork Contractor. No fabrication drawings issued above baseplate details – steelwork checked by overlaying the Architect, Engineers and Steel Fabricators 3D Models in a SDNF file. New and innovative transfer of information.

Design was undertaken to withstand the onerous applied loads and constraints:-

  • 150mph winds
  • 5m high snowdrifts
  • Freezing temperatures
  • Heavy roof cladding – approx 90T granite slabs on the roof
  • Deep roof build-up reduced the maximum depth of the 13m long beams. Beams also had to be tapered at the ends to suit the architecture
  • Fabrication, erection and on site checking was made easier due to the trial assembly, where several connections were able to be welded up to reduce the number of elements to be fitted on site.
  • Trial assembly also assisted the design of the other items – cladding, windows, the Corus Kalzip roofing system etc. Everything was checked for fit before going to site.
  • Success! No significant queries were raised when work was underway at the summit as every problem had been eliminated.
  • Everything taken to site had to fit on a 11m long x 2.5m wide bespoke flat bed truck. Skill and workmanship
  • To a high level. Trial erection helped as it ensured that the erection could be undertaken in a carefully controlled environment.
  • Skill – erecting a building on top of a mountain says everything.
  • For Health and Safety reasons the least amount of work required on the summit the better – the trial erection enabled several connections to be welded up to reduce the number of elements to be fitted on site.

Integration of Structure and Services to meet Architectural requirements.

  • The architectural form governed the design.
  • 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 – the stainless steel CHS columns in the glazed areas.
  • Stainless – mild interface. The isolation of the two materials was essential even at complicated junctions where large forces had to be transferred from one member to another – see Cruciform connection detail.

Efficiency and effectiveness of fire and corrosion protectionThe majority of the steelwork is galvanised. This will 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. This will ensure the durability of the steel frame. All galvanised steel was sent to various galvanisers across the country, this was due to some of the unusual shapes of steelwork and finding galvanising dipping tanks to suit these shapes became quite a challenge.

It was designed to be inherently a non-combustible building and evacuating it would be more dangerous, due its location, and staying inside would therefore be the safer option. Innovation of design, build and manufacturing technique

After fabrication, galvanising and transportation to site the project was erected by the Evadx team after it was painstakingly lifted piece-by-piece up the mountainside on the mountains dedicated railway link. Carillion worked with the Snowdon Mountain Railway Company to arrange travel for workers and material to and from the summit before and after tourist trips. This was enabled through specially arranging trains, and through manufacture and use of a bespoke flatbed truck for material transportation. As a consequence of this unconventional journey 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.