Mecanoo

■ EDIFICIO PRE ESISTENTE - SCALA 1:1000 EXISTING OFFICE BUILDING - SCALE 1:1000
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EDIFICIO SMANTELLATO - SCALE 1:1000 STRIPPED OFFICE BUILDING - SCALE 1:1000
Alkmaar’s new Cultural Centre on strategically situated Canadaplein square on the edge of the historical town centre houses the Municipal History Museum, Central Library and the Artiance Music School. The architectural challenge was to combine three different functions in one building on a narrow site, and integrate an existing structure: the former 1970’s Interkruis building. Although comprising one volume with a common auditorium, the design preserves the individuality of the three institutions, which are set side by side in an east-west array so that each faces onto the main square. The library to the south is largely contained in the former Interkruis building. Warm materials like Oregon pine and sandy-coloured linoleum give it a restful, comfortable atmosphere. A succession of patios and cleverly arranged empty spaces allow daylight to penetrate deep into the building. The music school to the north has a three-storey entrance onto the square. Steel and birch doors and black linoleum add further elegance. Daylight pours in from the glazing at the end of corridors. The municipal museum, requiring minimum daylight, occupies the central strip. Its glazed roof gives the feel of a covered urban square leading to the central hall and lends this compact structure a striking transparency and lightness. A major feature is the common auditorium which hangs in the central hall like an weightless white box. The old building has a skin of wooden slats which cover the glass façade of the new structure while at the same time giving an enticing glimpse of old-new contrast. The overall layered effect is soft and transparent, creating an ideal blend with nearby buildings: a large, imposing church and the small buildings of the old town centre. On the technical level, the pre-stressed concrete floors belonging to the former building were preser ved since their carr ying capacity of 6kN/m2 was sufficient for the building’s new function. The ground floor slab did not meet specifications, however, and was replaced with a new 230 mm composite flooring system laid on the existing foundations. Where necessary, steel beams were placed for extra support. During excavation of the basement, high groundwater level was a problem. The building pit had to be drained continuously until sufficient weight had been added to counter groundwater pressure. Since watertight walls and floors in the basement allowing fail-safe moisture control are prime requirements for a museum containing valuable works of art, intricately structured horizontal reinforcement and concrete with a water/cement ratio of <0.45 were used. Because of the large spans (up to 13 m) and high groundwater pressure, 400 mm flooring was laid. 800 and 900 mm weighted strips were added at intervals. Integrated reinforcement steel beams allowed considerable reduction of total floor thickness. Part of the building’s supporting framework functions threedimensionally. Walls are not placed on top of each other but “hang” between other cross-placed walls. Indeed, it is sometimes unclear how they transfer their load. The effect is often surprising, accentuated by the frequent use of voids. Several staircases are 120 mm prefab concrete steps protruding 1.80 m from the concrete walls. As steps and landings were mounted after the walls were constructed, placement required the utmost accuracy.
022Βιβλιοθήκη 023Il nuovo Centro Culturale di Alkmaar situato nella Piazza Canadaplein, punto strategico ai margini del centro storico della città, ospita Il Museo di Storia Municipale, la Libreria Centrale e la Scuola di Musica Artiance. Da un punto di vista architettonico la sfida è stata quella di combinare tre differenti funzioni in un unico edificio su un’area ristretta, inglobando una struttura preesistente: l’edificio Interkruis costruito negli anni ’70. Per quanto si tratti di un unico volume con una parte di uso comune il progetto salvaguarda l’individualità delle tre istituzioni che sono posizionate una di fianco all’altra con allineamento est-ovest in modo da permettere ad ognuna di affacciarsi sulla piazza principale. La libreria, a sud, è comodamente sistemata nel precedente edificio Interkruis. Un materiale caldo come il pi