1.Location of the building on the designated site

The Baobab Library accommodating the Modern-Age Collections and Services of the National Library of the Czech Republic inserts itself as a translucent and hyper-compact monolith in the Borough of Letnà nearby the boundary and within the protective area of the Prague Protected Monument Area. The minimal, sober and poetic architecture of this new building located on the Prague’s plateau is divided into two interconnected volumes : the HUB and the BELVEDERE.

1.1.The horizontal HUB :

The HUB is a horizontal volume that covers the whole site. As its structure is relatively low, it hangs to the typology of the surrounding buildings. A planted coverage on its exterior façades as well as on its roof changes it into a landscape origami. Its plan is opened and split in different functional entities, that are punctuated by planted interior gardens and gathered around the main library hall. The interior streets are dedicated to the public and are the natural continuation of the exterior urban flows from the underground station and tram stop on Milady Horakové Avenue in the North, from the Park Letenske Sady in the South-East and from the tram stop in Badeniho Street in the South. The entrance access emphasises thus the main existing pedestrian paths. The roof of the hub is not put on the main entrance along the Avenue and creates thus a square that connects the geographical difference in level. The bookshop and the exhibition room animated this square. On the southern side, the literary café invited the park walkers whereas on the eastern and western sides the two patios planted with bamboos mark the entrances of the 300 employees.

1.2.The vertical BELVEDERE :

The BELVEDERE is a vertical volume located in the centre of the hub from where all the vertical flows are connected by linking the Library. It distinguishes itself from the Prague’s Skyline and imposes through the purity of its lines an extreme romanticism respecting the beauty of the nature. It is a cube with a double bioclimatic layer, whose lone position with all façades equally exposed will stress the urban skyline. It takes the most advantage of the opening configuration on the historical panoramic landscape of the Letenske Sady Park and the Letenska plain. It is a great urban space offering to the public panoramic views by dominating Prague’s Castle with St. Vitus's Cathedral and Petrin hill with its sightseeing tower.

2.General concept of the architectural design

2.1.The BAOBAB, a maximal interconnection of the operation scheme :

The two main monolithic volumes of the project, the HUB and the BELVEDERE, are linked together by the BAOBAB with an organic architecture. It is the heart of the spatial system of the New National Library of the Czech Republic.

From the public space of the Avenue to the top of the Belvedere, the baobab links up with fluidity the different levels of access and safety necessary to the good functioning of the project. As metaphor, we can compare it to a true tree growing in the bowels of the building. It is actually composed of a trunk (the vertical circulations), of branches (the reading rooms and the work places) and of buds (the access ways to the National Archival Collection).

2.1.1.The Trunk : It gathered all the vertical circulations and organises the flows and the control areas of the public, the employees, the external entities. It is the main support structural element of the baobab.

2.1.2.The Branches : They house all the reading rooms opened to the public, the workplaces of the employees, as well as the restaurant, the café and the convention centre. Each branch of the baobab crosses through and through the cube of the belvedere and creates then scenic views and an exceptional workspace towards the Flatland in the North and the Letna valley in the South. Their ends open themselves on wide panoramic terraces, true de relaxation and meditation spaces. Conversely, the storage rooms and their 10 million items, are disposed in balconies between these branches and the auto-supporting concrete lattice layer of the belvedere. The spatial organisation of each room is studied in order to be totally flexible, modular, easily dismountable and according to modifiable solutions.

2.1.3. The Buds : The storages rooms of the national Archival collections are all directly connected to the work and study places contained in the branches of the baobab by footbridges named buds. They enable to create the interfaces of control.

2.2.The maximal opening on the City with minimal environmental impacts :

Further to the methodical organisation of the internal programmation of the project, the building is expected to use modern technologies reducing energy requirements and saving total operational costs.

2.2.1. The scenery origami : the HUB and its planted coverage in relation with the Letenske Sady Park will also enable to absorb the noise pollution and the the CO2 discharges. Composed as a vertical garden that folds and unfolds itself, this Japanese origami will form a case of nature varying according to the seasons and will offer itself to the surrounding buildings especially to the Embassy of India and to the Christian Community of the Czech Republic on the western side.

2.2.2. The double layer : The BELVEDERE is made of a double layer. On the one hand, the exterior layer is composed of inflatable cushions in polycarbonate film. This light and totally transparent layer creates thus a buffer zone managing the temperature differences between inside and outside. On the other hand, the layer of the interior cube is made of a concrete lattice accumulating the heat coming from the sun radiation. This one heats then the in-between that is naturally ventilated and moderate the interior atmosphere. The lattice becomes progressively denser so as to create an effect of mass and a protector screen around the collections. Moreover, the emergency stairs go along the 4 façades and offer a continuous oblique promenade all around the building. At night or when the library is closed, the double layer illuminates itself according to a parameterized colorimetric range related to the intensity of the traffic of the avenue.

3.Description of operational and spatial relations inside the building

The parking planned for 400 cars and the technical rooms are organised on four underground levels. They are arranged so as to respect withdrawal areas for the building of a new city ring road tunnel. A direct access is planned from the tunnel to the first parking level of 3.50 m height under beams. The vertical cores lead to the ground floor in the public area. From the hall, all the programme functions superpose themselves vertically in the baobab and are layed out at each level by the storage balconies of the National Library Collection. The split axonometry shows clearly the integration of the operational scheme by respecting the colour code of each function.

The conception of the new building of the National Library of the Czech Republic is focused mainly on users and their well-being in relation with the landscape. The challenge is to open an institution which is traditionally withdrawn on itself because of its first nature of National Archival Collection. Thanks to a welcoming architecture, the objective of this library is to clearly establish its role of institution opened on the world by reinforcing its social and cultural identity. The library do not have to be intrusive but omnipresent !

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