In accordance with the functional and aesthetic consistency objectives, two main types of underground station were designed in Brescia: deep-level and semi-underground ones. The deep-level station, having the platform level 22 meters below street level (the so-called zero level) is a type of station that repeats, with small modifications, in Casazza, Ospedale, Marconi, Stazione FS, Bresciadue and Volta. The semi-underground station, having the platform level 7 meters below street level, is repeated for Prealpino, Mompiano, Europa and San Polo. In these stations the basic principles of the project are all met. This result was achieved thanks to the competence of Cremonesi Workshop and technological-constructive know-how used by the construction company of civil works: Astaldi S.p.A.
The deep-level station is undoubtedly the most complex and the most significant one. In order to bring the natural light on the platform and visually communicate with the zero level the first problem to be solved was emptying the space above the platform, which was an obstacle to the set design specifications. It was therefore decided to divide the volume of the station in two asymmetric parts, one for access of the public, the other for the systems. In order to define these two features is an inclined wall located on one side to support the ceiling and the intermediate floors of the system area and, on the other hand, to define the station as a single volume, sometimes dilated and sometimes compressed, crossed only by light gangways and escalators. The continuation toward the outside of this wall also allowed to create some skylights able to penetrate the natural light to the platforms. Form, function and technique were thus solved by a single structural aspect that by defining the architecture of the station, evenly organized its space.
The material selection criteria
The choice of having stations that are all the same, aimed at giving strong uniformity to the whole project, led to design the same finishes for all the stations. The criteria used in the selection of materials to be used in the stations and in complementary items had technological and performance reasons (highly efficient materials in terms of durability, strength, health and curability) and aesthetic, perceptual and of environmental comfort reasons (materials suitable for projects with articulated geometries, from colours and diverse morphologies and able to provide an excellent real and perceived environmental quality. The synthesis was represented by the choice of four main materials: natural stone, porcelain stonewear, metal and glass.
The areas accessible by users, the floor and some surfaces and items are in diorite. It is a natural stone halfway in the family of granite and gabbro. It has excellent characteristics of strength, durability and serviceability and is specifically indicated in city contexts and infrastructures where critical conditions occur from the point of wear and safety. Suitably machined to the surface, it is shown to the user already at the exit facilities and of connection between the city surface level and the hypogeal spaces of the underground offer. In this context, the stone features the cladding of external parapets and partially of the vertical walls of escalators and fixed stairs. The flights of stairs are also diorite-cladded, both at the tread and the riser.
Interaction between background noise and signal
The conformation of the volume of the station emphasizes two dominant elements: the vertical façade and the surface of the inclined wall. The first, in porcelain stoneware in grey/light blue shades, dig the space in the soil thus creating the "box". The second, panelled with electrocoloured stainless steel reflective panels, with its diagonal "remarking" profile, is on one side the bearing item of the overhead ceiling, and on the other hand "measures" the emptiness of the inside space by expanding and contracting it. To these two elements the horizontal surface of the floor is then added, to a lesser extent as quantity, but equal as perceptual impact. From the colour point, amongst these three items, the "background noise" derives, for quantity reasons, from the vertical facades.