The Dome of Discovery.
The Dome of Discovery dominated the Festival of Britain site. When completed just in time for the opening of the Festival in May 1951 the dome, with the adjoining and needle-like Skylon, became the instant visual symbols of the Festival. Both were to appear in The Eagle comic, where they were analysed and explained for the delight and edification of the nation's mechanically minded youth and, standing side by side, they made quite a sight. Percy Levy, a director of the demolition company chat was eventually to dismande both the dome and the Skylon, still chuckles at the memory: `it was a phallic symbol really, the dome and the thrusting spire. Every exhibition has to have something like this'.
This interpretation of this pair of pioneering structures would, no doubt, have come as a surprise to the serious young architects who created them. Powell and Moya in the case of the Skylon and, for the dome, Ralph Tubbs. The Skylon was the odd-man-out of the major Festival structures. It was a monument pure and simple with no functional purpose beyond housing an anemometer at the tip of its 300 foot high spire. The Festival organisers had asked for a `vertical feature' and Powell and Moya won the competition with their remarkable post-tensioned cable design. As Moya admitted just before his death last July, the daring nature of the structure -- with its tall, cigar-shaped aluminium-clad body suspended almost invisibly by only three cables -- was the work of his former tutor at the Architectural Association and brilliant engineer Felix Samuely; `By an amazing stroke of genius he arranged a system of hydraulic jacks underneath the three smaller pylons. Once the whole structure was assembled, he pumped up these jacks and raised the pylons. This put tension or stresses into all the cables and by doing that the whole dining became a stressed structure. This reduced the number of wires needed to anchor the Skylon and halved the amount of oscillation in the structure. This lack of support made the structure look tremendously hazardous. You felt that there weren't enough wires to hold it up, which made it tremendously exciting.'
The dome was a structure of a very different order, but no less radical and pioneering in its concept and its construction. Indeed, if the dome had lasted longer than a mere I I months, and if its lessons had been accessible to later generations of architects, then it would no doubt now be regarded as one of the seminal buildings of post-war Britain. As it is, the fascinating story of the design and construction of this remarkable building has to be gleaned from contemporary drawings, photographs, descriptions and, by great good fortune, from the architect himself.
Ralph Tubbs, now aged 80, was one of the key figures in the development of the architecture and planning of the Festival. He had written a series of books during the 1940s, including Living in Cities, (1942) and The Englishman Builds (1945). These had caught the attention of the organisers of the Festival, notably Gerald Barry, the editor of the News Chronicle. Consequently Tubbs found himself one of the architects, along with Hugh Casson, enlisted onto the Festival design team in 1948. Initially, as Tubbs explains it, the team was charged with evolving designs that `would tell a story about what Britain had done in the past'. Ultimately, as part of the realisation of the ideas generated by the team, Tubbs was to be given responsibility for the layout of the upstream side of the Thames-side Festival site with Casson taking responsibility for the downstream portion.
Tubbs retains a series of drawings, possibly the last set in existence, which throw a fascinating light on the evolution of the design of the Festival site and on the development of several of the key Festival buildings -- notably the Dome of Discovery. Among the earliest drawings is a `sketch layout' by Tubbs for the entire site. Dated 26 August 1948, the layout shows a `concert hall' located where the Royal Festival Hall was ultimately to be built, and a `walkway and travelling seats' attached to Hungerford Bridge to link the Festival site with the north bank of the Thames. But, most interesting, on the site of the future Dome of Discovery, Tubbs shows a large round excavation which was to accommodate an `underground display [about] mining and tunnelling'. 80 already the idea of a large round feature for this part of the Festival site was established.
At about this time, as Tubbs remembers, `the design group resolved that the Festival should have at least one building that was technologically unique, a step forward that had not been taken before. `By extraordinary coincidence', says Tubbs, `the design group, at this critical moment, received an advertisement in the post from a firm that made aluminium domes. Suddenly it became clear that the round feature could be domed, the largest in the world and constructed using latest building technology and materials. It would be a showcase of inventiveness and of British discoveries housed in a structure which itself was a display of pioneering British invention. It was to be a monument to the ingenuity of the twentieth century. As Tubbs explains, `we got together with the firm and asked them if they could make a bigger dome. They said they could'.
A drawing by Tubbs dated 17 November shows the mighty round hole of August transformed into a circular, domed and buttressed building. As the legend explains, it was to be a pavilion dedicated to "creative though"' with displays on the `dissemination of ideas', medicine and exploration.
But who was to mastermind the design, detailing and construction of this pioneering piece of highly engineered architecture? Tubbs seemed the obvious candidate since he was the architect responsible for the design of that portion of the Festival that the dome would grace. The design group had already taken advice about the feasibility of the project from veteran engineer Ralph Freeman of Freeman Fox. Armed with Freeman's advice and enthusiastic support for the scheme, Tubbs felt ready to take on the challenge.
Tubbs's own background made him an eminently suitable choice. He had studied at the Architectural Association, then `far and away the best school' claims Tubbs (and as regards the discussion of Modern architecture and construction this was probably true) and left in 1935 to work for Erno Goldfinger. `I wanted to know all about modern construction and decided that the best man for me was Goldfinger.' Tubbs worked for Goldfinger for no wages for a year and then returned in the late 1930s to work on the design of Goldfinger's own house in Willow Road, Hampstead. Tubbs then worked for Gropius and Fry, which was `not as stimulating as working for Erno', was the secretary of the MARS group in 1939 and spent `most of the war as a fire-watcher on St Paul's Cathedral because I could not get into the services due to a stiff right leg'.
Ralph Freeman was also the right man for the job. Although Tubbs was 36 and Freeman 70 there was, says Tubbs, `a wonderful sense of collaboration'. This was partly due, no doubt, to Tubbs's admiration for Freeman who had engineered the mighty Sydney Harbour Bridge (`more a pair of huge cantilevers than a bridge' observes Tubbs) and to Freeman's obvious interest and enthusiasm for the dome: `the old boy got quite excited about it -- it was something new for him'.
The dome was to push back the boundaries of building technology in Britain. Its 365 foot diameter (chosen because `it was an easy figure to remember' says Tubbs innocently) made it the biggest dome in the world. But the architect and engineer were not only concerned with the structural problems presented by the vast scale of the structure. They also had to design a building that could be built very quickly and fairly economically and which would be of imposing, futuristic appearance and contain the right type of internal space to make it memorable as an exhibition gallery.
One of the earliest challenges was to design a structure for the dome which would keep the total number of parts to the minimum and with members that could be prefabricated, transported to site and erected with the greatest possible ease, speed and efficiency. The response to this challenge led to the development of the extraordinary system of geometry which determined the dome's form and the design of its structural members. As Tubbs now explains `the dome was a kind of mathematical poem'. In the centre of the site was a brass pin from which all the dimensions were measured. From here was fixed the dome's 365 foot diameter. Eccentric smaller circles were centred on a similar pin 29 feet away; these determined the edges of the galleries within the dome, and generated the asymmetrical form of the aluminium apron undercutting inwards below the soffit of the dome.
Tubbs explained the aesthetic as well as practical thinking behind this aspect of the dome's geometry when addressing a meeting at the Institution of Civil Engineers in April 1951. The report of the meeting in the Institution's Journal for October 1951 explains that Tubbs stated that `there were three reasons for the undercutting apron and the eccentricity. First, a very large circular building in the middle of the exhibition would, if vertical walls had been constructed, have provided a 1000 foot run of identical view to the visitor walking around it, giving a sense of monotony and exclusion from the dome itself...It was essential that there should be a constantly changing view around the perimeter. Secondly, by providing the undercut an interlocking of inner and outer space was obtained...Thirdly, there was a need for shelter from the rain immediately accessible to the vast crowds in the open air'.
Related to these was the geometry of the dome structure. As Gilbert Roberts, of Freeman Fox, explained to the April 1951 meeting at the Institution of Civil Engineers: `The most important and urgent decision to be made in starting on the structural design was that of the type of construction to be adopted in the dome roof...After consideration of various arrangements of framing, a treble intersection system of ribs, all of which lay on great circles of the dome for the whole or part of their length, were adopted'. Nine ribs lying wholly on `great circles' (as segments of a giant circle) were arranged in three groups of three, set diagonally to each other, to determine the profile of the dome. These nine ribs formed the primary structure of the dome. This geometry had an intensely practical purpose. As Roberts explained: `The primary framework of ribs were conceived as segments of great circles because "the time allowed for construction was very short for a job of this size and it was realised that no structural firm could reasonably be expected to build the framework in its works...On the other hand, setting all these ribs at the site with their intersections all at exactly the correct level and then drilling all the joints in position was considered an unsatisfactory procedure [since] there would be no automatic check on the accuracy of the erection...It was desirable that as much drilling as possible should be done in the shop before erection [and I] thought this could be done provided the ribs lay on continuous great circles"'.
Another early decision was to limit the number of materials used. Concrete made the foundations, floors, galleries and the massive fins which supported the underside of the dome and the internal structure. Aluminium was used for the structural members of the dome and for its covering. As Tubbs observes `the advantage of aluminium was that its strength was adequate while being light. The only real problem with aluminium is that, unlike steel, if you bend it cold you weaken it at the joint or along the curve'. Since the structural members had to be curved to form the dome this problem had to be tackled with some urgency. The answer was to extrude the aluminium booms of the girders in the usual way and bend them to the correct curve while they were still hot. This technique of shaping the aluminium was proved not to weaken the metal.
Aluminium was also used for cladding the dome. This gave it the desirable futuristic sparkle. The sheeting was treated merely as weather facing -- not as a stress-carrying member as initially intended -- and was free to move in any direction tangential to the dome. The only steel used in the main structure was in the large box-section ring beam that formed one of the primary structural elements, taking all the bending and horizontal thrusts from the dome.
Keeping the dome stable in different weather conditions and the need to restrain its outward thrust were obviously major problems. Tubbs wanted to express the construction, and he and Freeman played initially with the idea of strong vertical piers connected to the under edge of the dome with sliding joints to take up movement. But it was soon realised that this type of construction could mean that loads were capable of being dispersed eccentrically. Indeed, it was theoretically possible for wind pressure to place the entire load of the dome on just a few piers.
Eventually Freeman came up with the idea of light but firmly held aluminium struts, each of which raked from a pin joint at the soffit of the dome to another pin joint in the concrete ring that formed the foundations. In this system the struts could move to distribute loads round the ring.
The interior of the dome must have been breathtaking. Tubbs devised a particularly theatrical means of entry. An escalator -- the longest unsupported escalator then built -- carried visitors into the dome with the interior being concealed until the actual point of entry. Then all was revealed, tiers of galleries and a majestically curving roof of gleaming latticed purlins and rafters cries-crossing in a pleasingly complex manner.
The Dome of Discovery could have survived. But the Festival of Britain had been a populist event and a brainchild of the Labour Government. The Conservatives came into power in 1952 and they could not see the back of the Festival and its buildings fast enough.
Tubbs pleaded for his dome but got nowhere. Lord Eccles showed some interest but eventually told Tubbs that he felt `tine dome had served its purpose and, anyway, how could he be sure that it would not leak in the future if it was preserved'. Tubbs with Freeman Fox sought alternative locations and uses. Negotiations began for its transportation to Sao Paulo for use as a sports arena, to Montevideo, to Coventry, where City Architect Donald Gibson declared its proposed demolition a `shocking waste of public funds', and to Sydenham -- the former site of the Crystal Palace. Transport of the dome to this London suburb was costed by Freeman Fox: total expenditure would have been 55 000[pounds sterling], including repairs and new bolts and rivets. But all efforts were to no avail.
In March 1952 the demolition contract was advertised for the dome along with most of the Festival buildings. Eventually the dome's aluminium was sold back to to its original suppliers, ICI, for 24 000[pounds sterling]. It had cost 300 000[pounds sterling] to purchase. The site of the dome was not built on.
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|Title Annotation:||pavilion in 1951 Festival of Britain|
|Publication:||The Architectural Review|
|Date:||Jan 1, 1995|
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