Municipal Library Viana do Castelo

The Municipal Council of Viana do Castelo intended to build a BM3-type library on the strip of land between River Lima and Marginal Avenue. The building is part of the Plan for the Marginal of Viana, whose author is Prof. Fernando Távora. Furthermore, this Plan foresees the development of external spaces, and the construction of a multi-purpose hall and two buildings equipped with two office buildings, framing Liberdade Square and the monument to April 25th.

The building area was agreed with Prof. Fernando Távora and the rest of the architects involved (Eduardo Souto de Moura, José Bernardo Távora and Adalberto Dias). Located at the eastern end of the planned sequence of construction, the Library consists of an elevated volume of 45x45 m which includes a central opening of 20x20 m. This volume extends to the east on the ground fl oor, which is “L”-shaped and has a dwarf wall framing the riverside gardens. The building programme follows the Services and Areas Proposal and the recommendations issued by the General Directorate for Book and Libraries (IPLB) regarding the National Network of Public Libraries, as well as other directives laid down by the Municipal Council and the POLIS Programme. 

The layout of the building is as follows:

Ground Floor (Level 0) 

- Public Facilities: Atrium, Information Desk, Bar, Storage room of Bar, Multi-purpose Room, Storage room, Toilets. – Staff facilities: Reception/Maintenance, Director’s office, Work rooms, Technical support services, Meeting room, Computer room, Staffroom, Toilets, Storage rooms.

1st Floor (Level 1) 

- Atrium, Reprographic Services, Toilets, Adults section, Children’s section.

The communication between the two floors is by means of two stair/ lift cores, one of them for the public and the other for staff. There is also an external escape stair. Public access to the library’s atrium is via the space defined by the elevated volume and its corresponding central opening, the ground floor being elevated 65 cm above ground level. The difference in height is overcome by a ramp with a gradient of four degrees. Staff access is through the public Atrium and a covered space located on the east side of the Library, which is planned to be used as a staff car park. The P.T. and the boiler are next to this covered space. The proposed architectural expression arises from the following conditions: - Views over the river from many parts of the building, due to its elevated position, supported at both ends (East and West) by means of two “L”-shaped pillars, and from the built area on the ground floor.

- Orthogonality of the floor plan and elevation.

- Predominance of large horizontal openings, illuminated with spotlights.

- Sun protection or adequate orientation of the openings.

- Exposed white concrete façade partially clad in stone, which forms

the basis of the building.

- Volumetric definition intentionally subject to the dialogue garden/construction.

Structural Description: The Municipal Library of Viana do Castelo building has two floors which are structurally divided into two different areas: The first one (zone 1) spreads in a continuous manner across the ground floor over the foundations, and the second area (zone 2) is supported by the former zone and by two “L”-shaped pillars, freeing space on the lower floor as it was envisaged in the project. Foundations: The existing ground is characterised by its heterogeneous terrain, with stone blocks of different types over a rock layer that varies in depth from 10 m in the north of the site to 20 m in the south. For this reason, the foundations are built up indirectly by means of jet-grout columns covering micro-piles (Type IV) sealed to the rock. The predictable difficulty in carrying out piling works led us to choose this option. The part of the building that rests on the ground is made up of slabs and walls with orthogonal mesh, resting on those columns in a continuous run along the walls. The “L”-shaped pillars from the elevated section stand on a reinforced concrete block anchored in groups of jet-grout columns and micro-piles. Superstructure: There are two different situations to be considered: Zone 1: solid or steel/concrete mixed slabs resting on reinforced concrete walls. Zone 2: The structure here takes account of the existing openings and the exposed concrete finish, and it is made up of a structural steel framework covered with reinforced concrete.

The adopted structural plan consists of a grid of interconnected beams at roof level that rest on zone 1 of the building and on two cross-shaped metal supports, which turn into two “L”s under the first floor and which, for architectural reasons, have one of their wings oriented in the least favourable direction, causing stresses on the outside of that wing. This metal grid supports the Library’s first floor by means of ties. That floor is made up of a mixed structure of metal beams and reinforced concrete plates on both its upper and lower sides (exposed concrete). Taking into account that the whole elevation should suffer the least possible strain, the stressed area of the cross-shaped supports is reinforced with Dywidag bars, whereas the mixed slabs from the suspended floor are post-tensioned.

Finally, the use of exposed concrete and white concrete, the particular characteristics of the work, the stereotomy design, the presence of metal structures, its proximity to the sea, the different concrete thicknesses, etc. requires a rigorous study of their composition and of the formwork. The building contractor’s remarkable collaboration in the direction and planning of the works, made it possible to reach a satisfactory outcome and with the required quality.