Central Library TU Delft

The fascinating site for the new library on the 1960s campus of the Delft University of Technology is overshadowed by a large, brutalist concrete auditorium from the Team Ten architects, Van den Broek & Bakema. The concrete surroundings inspired a radical change. The university needed a campus atmosphere: lawns with flowers and trees where students and professors meet informally on broad stairs. A library recalls the image of endless rows of books in cases reaching up to the ceiling. A modern library however is served by computers, books are stored in basements. It is a building where technique is displayed. In this way the program was formulated.
The Van den Broek & Bakema auditorium sits like a huge frog in the green grass. The vast lawn is lifted on one edge like a sheet of paper and shapes the roof of the new library. A roof that can be walked upon. The grass roof of the library is freely accessible for walking and lounging, creating a new amenity for the whole campus.
It is supported by slender steel columns in a huge hall enclosed with canted, fully glazed walls. The base of the slope to the west is marked by a broad flight of steps leading up to a recessed entrance. A huge cone pierces the green expanse, articulated by a 1500 mm wide necklace of glazing in the plane of the roof. Supported on splayed steel columns, the cone houses four levels of traditional study spaces connected by a helical stair. Within the cone, a central void provides daylight from a glazed roof to the internal reading spaces. The apex of the cone is formed by an open frame. Extending forty metres above grade and floodlit at night, the cone acts as a beacon on the campus day and night.
The density of the mass of the planted roof has significant insulating properties, so that the interior of the building is less susceptible to changes in temperature. In addition, the mass provides excellent soundproofing, and gradual evaporation of rainwater held by the vegetation provides natural cooling in the summer. To avoid disfiguring the roof landscape with mechanical cooling units, and also for ecological reasons, cold storage - the capacity to store cold or heat in ground water - is used. For this building, the storage is in a layer of sand at a depth of 45 to 70 metres below grade. The sand is sealed off above and below by an impenetrable layer of clay. Two tubes stand vertically in the sand 60 metres apart. In winter relatively warm ground water is pumped up through one tube, used to temper the building until it cools, and then pumped back into the other tube. In summer the water takes the opposite route, with the relatively cold ground water being used to cool the building.
The glazed facades also play a critical role in the environmental strategy of the building. These facades consist of an outer double glazed unit, a 140 mm wide ventilated air cavity with solar shading, and a sliding inner leaf of toughened glass. Air is supplied into the cavity at floor level and sucked out at high level on each floor. Opening windows incorporated in the facade are small so as to disrupt the flow of air within the cavity aslittle as possible.
The building provides approximately 1000 study spaces, 300 of which are equipped with computer terminals. In addition to the study areas within the cone, spaces are provided at ground and first floor levels adjacent to the glazed north facade. In contrast, most of the books are kept in temperature and humidity controlled storerooms in the basement. They may be requested for retrieval by library staff and are delivered to the circulation desk by a glazed elevator. Some 80,000 volumes of the most recent publications are available to the public. These are tangibly close at hand, displayed in a four-story, suspended steel-framed bookcase silhouetted against an ultramarine wall. Finally, thousands of current periodicals are on open display at ground level. In addition to serving the local needs of university students and staff, the library provides distance reference and information services for many companies and industries. Designated as the national library for technical and natural sciences, the facility is also connected electronically to major libraries around the world. The library thus satisfies both electronic needs and the sensory pleasures derived from being able to touch and smell the books.
Staff offices are planned at the perimeter of the building, rising to five stories at the southeast corner. The east wing is designed as a double loaded corridor with support facilities on the dark interior side and offices along the glazed outer edge. The offices look out through a slender canted colonnade to a row of mature trees along the street. The south wing is single loaded, with open circulation galleries and stairs expressed within the large central space of the library. The office wall along this corridor is a collage of transparent and several kinds of translucent glass, and the exterior window wall of the offices is fully glazed. The rich quality of dappled light admitted into the heart of the building through these many layers of glass helps to activate the vast interior space. Likewise a book shop and a coffee bar activate the library socially.