Alinghi Base for the 32Nd America's Cup, Valencia, Spain
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Alinghi Base for the 32nd America’s Cup, Valencia, Spain Peter Tanner, Civil Eng.; and Juan Luis Bellod, Civil Eng.; Cesma Ingenieros, Madrid, Spain Introduction bases were unknown during the design lounge. The roof is also fitted with a stage, the organization decided to pro- bar. On 2 March 2003, Team Alinghi went vide the shell only, leaving the outfit- down in history for defeating Team ting to each individual team. Further New Zealand to bring the America’s to Team Alinghi’s service criteria, its Conceptual Design Cup (AC) to Europe for the first time base is double the size of the standard in over 150 years. After that victory, base defined by the AC organizers. Overall System the Société Nautique de Genève, Swit- From the outside, the viewer sees a The framework envisaged for the Alin- zerland, on whose behalf Team Alinghi prism-shaped building, 68 m long, 39 ghi Base was fairly conventional, with competed, together with the Challe- m wide and 13,5 m high (Fig. 1). The steel columns, composite beams and nger of Record, the Golden Gate sea-side south facade has two large composite slabs (Fig. 1). The design Yacht Club, announced the creation of entrances to the boatshed, positioned called for continuous columns, from America’s Cup Management (ACM), between axes 2’ and 4’ and 5’ and 8. A the foundations to the roof (Fig. 2). an independent company mandated to third opening (between axes 12 and 13) Longitudinally, they were spaced from organize the 32nd AC. On 26 Novem- corresponds to a corridor that crosses 5 to 18 m, whereas transversally the ber 2003, ACM announced that Valen- the entire building to provide access to standard spacing was 5 m, except in cia, Spain, would host the 32nd AC. The the jetty from the building’s street-side the corridor between axes B and C programme for this edition of the AC facade. The rest of the south facade is (Fig. 1(c)), where columns were spaced included an ambitious 4-year schedule panelled or glazed, the latter particu- at 5,5 m for architectural reasons. Fi- of regattas starting in 2004 and culmi- larly on the second storey, where the nally, the corridor running from axis nating in the AC Match, to be held be- 4,5 m wide balcony off the VIP lounge A’ to axis B was to be bounded by the tween 23 June and 7 July 2007. is accessed through glass doors. This slanted glass facade, varying in width As a result and within the framework of balcony also stretches around half of from 0,7 m on the ground to 2,9 m on a more ambitious urban development the length of the east facade, likewise the second storey. On all storeys, the project, the Inner Harbour of the Port windowed at this level. The street-side main beams were to run parallel to facade consists in a slanted glass wall. the longitudinal facades of the build- of Valencia has been reconditioned for 2 the AC event. The infrastructure works The total usable area, nearly 7000 m ing. The distance between these beams included, among others, 12 bases that counting the four storeys (including was to be spanned by a composite slab would serve as homes before and dur- the accessible roof) into which the with shaped steel sheeting to avoid the ing the regattas for the defender, Team building is divided, is occupied by of- need for any transverse beams, except Alinghi, and each of the 11 challengers fices, meeting rooms, a gymnasium, a around the edges to tie the structure from all over the world. In an environ- restaurant and a shop, in addition to together during construction. This lay- ment in which the most recent scien- the aforementioned boatshed and VIP out, free of any secondary steel girders, tific and technological innovations are put immediately into practice in pursuit of lighter and faster boats, the (a) 122′ 344′ 5 5′6 7 8 9 10 11 12 13 14 15 16 challenge was to deliver sound build- A Street A′ ings based on modern structural solu- B tions, in which the design objectives C of safety, serviceability, economy and D elegance were to be achieved mainly E by means of coherent conceptual de- F 39,15 sign, efficient use of materials and G good detailing. This paper describes H the structural concept underlying the I J Alinghi Base, along with the solutions Sea for a number of structural details and 68,0 certain constructional considerations. (b) (c) A A′ B C DEFG HJI Keywords: Alinghi Base; composite variable structure; hollow section; bolted con- min. + 13,4 nection; composite joint; glass facade. – 0,35 Street Sea Architectural Design 7 10,5 6,910,6 18 5 55 4,5 3,65 5,56 × 5 4,5 Inasmuch as the various AC partici- Fig. 1: Alinghi Base structure (a) plan view at first storey level; (b) longitudinal section; pants’ needs and preferences for their (c) cross-section (Units: m) 192 Structures Worldwide Structural Engineering International 2/2008 xx316.indd316.indd 119292 44/14/08/14/08 12:26:3712:26:37 PMPM HEA 360 sections (Fig. 1(b)). For the composite roof beams with span lengths of 18 m, however, the design specified 1005 mm high steel I gird- ers to withstand the loads generated by the accessible roof and suspended second storey. These beams would also have to accommodate large web per- forations for mechanical and electrical services, with heights of up to 50% of the girder height. As the first storey beams between axes 8 and 12 were to be exposed, composite truss girders were to be used in this area for rea- sons of aesthetics. With a total height of 1270 mm, these trusses would con- sist in HEB 180 shapes on the top and bottom chords and HEB 120 sections for the diagonals. Fig. 2: Alinghi Base during construction, view from the jetty In each composite beam, the composite slab would constitute the top flange, to which the respective steel girder was allows to minimize the number of ele- impact, using the adjacent columns to be connected. The total slab depth ments and on-site connections. as chords. On the sides of the build- envisaged was either 0,12 m (first sto- ing, the bracing systems were there- rey between axes 1 and 8) or 0,18 m 2 A 640 m column-free area was envis- fore positioned between axes C and D, (all other areas), depending primarily aged for sail drying on the ground while on the slanted facade they were on the magnitude of the live loads. The and first storeys, between axes 8 and set between axes 1 and 2, for here only viability of the composite slabs, with 12 and B and I, respectively (Fig. 1). the area bounded by axes 4’ and 15 span lengths of up to 5,5 m and the Owing to spatial limitations in the sec- was to be glazed. The composite slabs aforementioned overall depths – for ond storey that affected the compos- would act as diaphragms, transmitting slenderness ratios of 46 and 30, respec- ite system, the longitudinal beams had any horizontal forces to the bracing tively – would be dependent upon the intermediate supports in the form of systems. use of lightweight aggregate concrete, hangers connected to the roof beams, LC, with a density of 1800 kg/m3 and a the strength and stiffness of which characteristic compressive strength of Structural Members were to be enhanced accordingly. By 40 N/mm2. Given the seaside location contrast, the height available in the The engineer’s design called for col- and the presence of large openings in first storey system sufficed to solve umns made of square, 8 mm steel hol- the south facade of the building, the the 18 m span length between the col- low sections measuring 300 mm on each admissible chloride content estab- umns at axes 8 and 12 with simply sup- side, which up to the first storey would lished was 0,1% of the bulk weight ported composite truss girders spaced be filled with concrete. The latter was of the binder. While there are manda- at 5 m centres. a safety measure adopted to increase tory standards in prestressed concrete, the fire resistance of the columns, in such a requirement is not normally Although Valencia is not a seismic re- light of the type of work conducted in applied in composite structures. The gion, the building was to be fitted with the boatshed. Wherever possible, stan- overall depth of the steel sheeting to a bracing system to transmit the hori- dard rolled steel I sections were used be used in the composite slabs posi- zontal forces due to wind action and for the composite beams. With a stan- tioned transversally to the beams was sway imperfections to the foundations, dard spacing between beams of 5 m, 75 mm. With the span lengths adopted, a solution that entails a series of advan- IPE 400 shapes were used in the first the steel sheeting available would tages over the sway frame design. Both storey areas subject to small live loads have been unable to transmit the hori- horizontal displacements and column (characteristic value = 2 kN/m2) and zontal shear at the interface between buckling lengths can be reduced, the having a maximum span length of 7 m the sheet and the concrete by means former being particularly important (between axes 1 and 2’, Fig. 1(a)). In of mechanical and frictional interlock- to ensure the appropriate behaviour all areas with live loads ranging from ing alone.