By Livio Dell’oro, Stefano Guanziroli, Giulio Gerosa & Elena Campagnari (Studio LDA - IDeCOM)
The city of Lecco, closed between its mountains and the famous lake, is surely not an overpopulated town, but it requires additional space. Its horizontal expansion is limited by the environmental boundaries and the forthcoming urban planning strictly undertakes the “reuse of the existing”. The increase of density within the City center assets is an ongoing process.
Furthermore, most of the public buildings require of extension and retrofit.
Light and sustainable construction materials, such as wood, allow to gain relevant performances minimizing the impact on the existing buildings in a seismic vulnerable environment.
The concept is inspired by the necessity of the Municipality to group offices actually spread into different areas.
The existing City Hall is composed by two main bodies: the historically valuable complex, hosting the Major and the Council offices, connected with to the old archives, a rather crumbling building requiring for massive structural and architectural refurbishing.
The complex is adjacent to the railway station, standing between recent commercial and residential constructions and the old city center facing the lakefront. The railway position, physically cutting the urban fabric, is a historical problem for Lecco.
The challenge is to match the requalification of the old building archives with the request of a new infrastructure, solving the disconnection in direct interaction with the railway.
Here the two main features of the composition: the building and the bridge. Both these items are technically conceived along the same fil rouge, the vertical extensions with wood structural systems and the rehabilitation of the existing.
The building vertical extension is reached by means of wood frames, radially arranged around the central block. The elliptical shape of the footprint brings to transversal moment frames each with different shape and span. The frames are connected with external and internal rings. Kerto-S/Q LVL elements are used for the frames composition.
The bridge is cable-stayed type. The inclined pylon is made with a composite wood structure: panels are installed at each cables level and connected axially with radial elements, resulting in its spindled shape.
The pylon is anchored above the reinforced concrete structure of an existing elevated water tank, a dismissed facility which, thanks to its strategic position, can be converted becoming the focal point of the new system.
Both the structures are modular and the “light bridge concept” is reproducible, considering the relevant amount of dismissed constructions (i.e. water tanks, pylons, industrial facilities) found close to the main networks, which might be overridden by pedestrian paths.
The new building is conceived as the new communication hub of the government towards the community, a space of interaction showing the public activities, collecting all the services having public interest.
The bridge is penetrating the building, in a game between structure and architecture. Here the social value of this infrastructure, which is creating an open corridor close to City Congress hall. This space, sided by a full height glass wall, is completely sheer towards citizens, transiting for personal reasons or using the bridge to assist to political disputes.