Cloud Tower / By The next ENTERprise - Architects

Grafenegg, Austria
The next ENTERprise - Architects
Post By:Kitticoon Poopong

Photo © Courtesy of Lukas Schaller

The site for the open-air pavilion is a park based on the model of an English landscape garden. In the 250 years of its existence, successive periods have left their traces, and this stylistic variety is one of the reasons for the park’s appeal.

Photo © Courtesy of Lukas Schaller

The area, with a castle and moat at its centre, has a size of approx. 31 ha. Parallel to the pavilion’s construction, works for a subtle contemporary replanting and restructuring of the historical park have been undertaken.

Photo © Courtesy of Lukas Schaller

The open-air pavilion is accessible year-round – as an attraction for flaneurs and excursionists and as stage during festival season in summer – changing its appearance with the atmospheric conditions and the seasons.

Photo © Courtesy of Lukas Schaller

The pavilion is inserted into the existing relational field of entrance gate, riding school, castle, ‘Black Gate’ and the ‘Große Senke’ (lit. transl.: large depression) and in the process re-contextualizes the network of views in the landscape. Through its topographical configuration it reinterprets formal elements of the landscape garden – the play with perspective and visual relations, with contraction and expansion, with enclosure and opening.

Photo © Courtesy of Lukas Schaller

The basic rule of acoustics for open-air stages, ‘what you see is what you hear’ serves as a cue to explore affinities between perspective and acoustic space. The topography of the existing depression – the ‘Große Senke’ – was emphasized by modeling the terrain. Artificial hillocks are created by further excavating the depression and subsequently redistributing the soil at its perimeter, thus creating the auditorium tiers. Clearly distinguished from the natural terrain by their geometry, stage and auditorium nonetheless merge fluidly with the topography of the site.

Photo © Courtesy of Lukas Schaller

As a spatial figure the pavilion is generated from elements of the landscape – the depression, the slope, the incision, the hillock – and the architectural folding of the roof. The ‘Schneise’ (loosely translated: an incision in the landscape) creates a vista linking the riding school to the ‘Black Gate’, and serves as an entrance to and a passage through the auditorium area. The staging of views and spatial sequences, the framing and hiding of points of attraction, often achieved by the meandering layout of paths in the traditional landscape garden, is a theme taken up by varying the elevation of the incision to achieve these effects.

Photo © Courtesy of Lukas Schaller

Coming from the main entrance, the visitor is enticed to proceed by the silhouette of the stage roof, visible behind an artificial mound. Immersing himself into the incision, he tunnels through the hill and – after passing this deep and narrow space – enters the wide arena of the auditorium and the stage, the stage roof suspended above it.

Photo © Courtesy of Lukas Schaller

TECHNICAL / STRUCTURAL

Acoustics Conceptually the pavilion is based on the idea of a structure that is not bound by any particular purpose and that is perceived as a stage only during performances. How can such a free structure serve as an acoustical instrument, able to focus sound energy and direct it to 1700 seats for an ideal music experience?

Photo © Courtesy of Lukas Schaller

Open-air stages are special acoustic cases, since strictly speaking they do not provide a spatial enclosure. Without reflection, direct sound prevails and music in these spaces is characterized by high transparency and clarity, coupled to extremely low spatiality.

Photo © Courtesy of Lukas Schaller

Topography was used to place the stage at a lower level relative to the surrounding terrain and to form the basis for the amphitheater-like tier arrangement of the auditorium, thus creating ideal conditions for an outdoor music venue. Additionally the structured geometry of the stage-roof and enclosing walls frame the orchestra and are crucial to build and direct the necessary sound energy. Convex metal panels suspended from the roof’s ceiling enhance the musicians’ reciprocal hearing. To ensure ideal hearing conditions for the audience, the average distance between stage and auditorium seat is limited to 30 meters, with the most distant seats positioned at a distance of 40 meters.

Photo © Courtesy of Lukas Schaller

Structurally the concrete lower part of the stage emerges from the topography of the terrain to support the metallic stage roof, suspended above the ground at the level of the surrounding treetops. The complex geometry and plasticity in both concrete and steel are structurally advantageous. The spatial distribution of loads in the folded structure activates membrane-tensions and reduces flexural stress, resulting in the use of slim, resource-saving elements. At the same time these characteristics required an exceptionally high degree of detailing and a precise preparation of the construction process.

Photo © Courtesy of Lukas Schaller

The folded concrete structure consists of slabs arranged at different angles around a 13 meter high concrete slab. All exposed concrete elements serve as climatic envelope, without additional weather-proofing.

Photo © Courtesy of Lukas Schaller

Special attention was devoted to the connection between concrete base and steel roof, since materials with different thermal conductivity meet. In summer, temperature differences of up to 40 K are to be expected, with the steel roof heating up to a maximum of 80°C. In order to avoid temperature-induced tensions at the interface between the two materials, the roof is placed on bearings.

site plan--drawing © Courtesy of The next ENTERprise - Architects

MATERIAL:

Conceptually, materials were chosen to underscore the open-air character of the site and to strengthen the bond between built structure and landscape. The stage is a monolithic structure of fair-faced concrete, embedded into an enveloping hillock.

floor plan--drawing © Courtesy of The next ENTERprise - Architects

The stage roof is designed as an autonomous, sculptured object. Suspended above the landscape on a level with the tree canopies it is placed among the groups of trees as if it were one more of them. The shiny metal surface on the outside reflects the sky and the trees, turning the roof into a cloud-tower. The audience tiers were designed using prefabricated concrete elements, compacted gravel surfaces and lawn-covered, geometrically precise hillocks.

section AA--drawing © Courtesy of The next ENTERprise - Architects

The hillocks take up a tradition for contrasting flowing, natural landscape formations with geometrical lawn-pyramids and exactly defined slopes that reaches back to the early years of the landscape garden, such as Prince Pückler-Muskau’s lawn pyramids at Branitz.

section BB--drawing © Courtesy of The next ENTERprise - Architects

The play of light on the surfaces gains in atmospheric density through the plasticity of the stage geometry. The materials chosen for enveloping the stage – steel and reinforced concrete – have the added advantage of being highly reflective and serve to build the necessary acoustic strength. The selection of colors – warm reds and browns used for some of the enclosing surfaces reflects the color spectrum of string instruments, and introduce an intimate element usually associated with indoor spaces to the stage area.

section CC--drawing © Courtesy of The next ENTERprise - Architects

Project Data
Project name: Cloud Tower
Location: Grafenegg 10, A-3485 Grafenegg, Austria
Program: music Pavilion, stage and auditorium with 1700 outdoor seats

Competition: Feburary 2005
Planning phase since: August 2005
construction since: July 2006
Completion year: June 2007
Stage structure: concrete; stage roof: steel/glass; auditorium: prefabricated concrete; stage backdrop: double-layered lightweight structure.

Seats: 1.670 auditorium seats, 300 lawn seats
Height of stage roof: 23 m
Stage width: approx. 20 m
Stage depth: approx. 11 m
Maximum orchestra stength: approx. 200 artists
Net floor area: 651 m²
 stage: 228 m² 
backstage area: 203 m²
 artists’ washrooms: 27 m² 
 Acoustic buffer: 16 m²
 artists’ wardrobes: 35 m² piano storage: 11 m²
 HVAC room: 15 m² Audience washrooms: 115 m²
Park area: 31,5 ha

The people

Client: Grafenegg Kultur Betriebsges.m.b.H., St. Pölten, A

Architects: The next ENTERprise - Architects - e.j.fuchs | mth.harnoncourt
Project team: Paul Vabitsch, Egon Niedertscheider, Hannes Oswald, Maja Ozvaldic, Marianna Milioni, Daniel Harrer, Waltraud Hoheneder, Claudia Cavallar

Overall planning: ARGE the next ENTERprise | Land in Sicht

Landscaping: Land in Sicht, Thomas Proksch, Wien / Vienna
Structural engineering: Ingenieurteam GmbH Bergmeister, Josef Taferner, Jochen Ehmann, Vahrn / Varna, I
Acoustics: Müller-BBM GmbH, Prof. Karlheinz Müller, München / Munich, D
Light design: Ploderer & Partner, Christian Ploderer, Wien / Vienna
Light planning: Wiltschko Lichtplanung, Berndorf, A
Calculation: sglw architekten, Werner Silbermayr, Wien / Vienna
Reinforced concrete materials consulting
: Ingenieurbüro Prof. Schießl, Christian Sodeikat, München / Munich, D.

Resident orchestra: Tonkünstler-Orchester Niederösterreich
Artistic director Grafenegg International Music Festival: Rudolf Buchbinder

Project management: NÖ Hypo Bauplanungs- und Bauträgergesellschaft m.b.H., Johannes Reiterlehner, St. Pölten
Controlling: Azberger-Höss ZT GmbH, St. Pölten

Construction supervision: BM Horst Pratter, Judendorf-Straßengel
Supervision landscaping: Land in Sicht, Andreas Beneš
Building physics: Wolfgang Hebenstreit, Wien / Vienna
Geological survey: Mario J. Pototschnik, Wien / Vienna
Site survey: Gerhard Senftner, St. Pölten
HKLSE-Planung: Christian Koppensteiner, Wien / Vienna

General contractor: Alpine Mayreder Bau GmbH, Zweigniederlassung NÖ, Horn
Steel construction: Pagitz Metalltechnik GmbH, Wien / Vienna
Prefabricated concrete: Alfred Trepka GmbH, Ober-Grafendorf
Drywall: Perchtold Trockenbau GesmbH, Wiener Neudorf
Schlosserarbeiten: Heinrich Renner Ges.m.b.H., Langenlois
Carpenter: Pöchlhacker Holzbau GmbH, Ybbs
Glazing: Rigo-Glas GmbH, Wien / Vienna
Paint: Farben Traht, Etsdorf am Kamp
Electrical installation & equipment: Eichinger&Stuber, Langenlois
Plumbing equipment & installation: Caliqua Gebäudetechnik GmbH, Wiener Neudorf
Garden & landscape gardening: Kanovsky Gmbh, Klagenfurt

Photographs: © Lukas Schaller

Note>>Location in this map, It could indicate city/country but not exact address.

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