The use of reinforced concrete, cast in-situ was essential to realise the design intent, which was for a voluminous concrete shell with interlocking volumes and expansive openings to bring light in and views out. This concrete shell is rigorously engineered and the plastic nature of the material fully exploited; long openings offer panoramic views where people sit while the tall portico that is the finale to the spatial sequence provides a portrait view of sea and sky. The sky lights the main library space through openings between the V beams that span the space.
The monochromatic, light-coloured concrete is more than a neutral background; this cast material literally moulds the space, and required craft in its making. Cast-in-situ concrete is in effect constructed twice; an on-site workshop was set up to make with precision the plywood forms that encase the liquid mix. Once the concrete was poured, forms and props removed, the shape and form of the building was gradually revealed.
The enormous “V” beams were made off-site using ship-like steel shutters and delivered at night to be tentatively eased on to their concrete perches, high above the reading room. These beams were then lined on one side with oak slats that absorb sound and screen the automated ventilation openings. Primary structural elements are elsewhere put into service for environmental systems. The spine of concrete shafts that define the plan are primary structural elements that also transport air extracted or supplied through the building assisted by the roof turrets.
The Awards jury said, “In this civic building, the use of large elements of concrete was a choice rather than a requirement. Having made this choice, the architect and design team have exploited the use of concrete to the full. The large, open well-finished concrete elements appear a near-perfect material for the spaces created – finished in areas with oak slats. The massive precast roof beams were a complex piece of construction well delivered. The contractor is also to be congratulated for the overall quality of finish achieved. Extensive use in this building clearly shows what concrete can add to an award-winning structure.”
Rue d'Arlon 55 - 1040 Brussels