RENOVATION PROJECT WITH INCREASE OF USEFUL SURFACE AT THE HEADQUARTERS OF THE COMPANY METALMOBILE S.A.S. LOCATED IN VIA GESSO 140 – ZOLA PREDOSA (BO)
CLIENT: Fin Mobile S.a.s. di Fabio Bastianini & Co.
SERVICES RENDERED: preliminary, definitive, executive project, DL and safety, civil, structural.
AMOUNT OF WORKS: 1.400.000 €
BEGINNING/END OF WORKS: 2008/2011
CONTRACTOR: EDIL 48 S.r.l., via vittoria 23 – San Lazzaro di Savena (BO) and FERRETTI FERNANDO di Ferretti Federico, via Agucchi 84/20 – Bologna
1. General criteria
The structural design of the work has provided various areas of intervention listed below:
- Design of a new building with independent reinforced concrete structure adjacent to a portion of the existing production plant and design of new external perimeter containment walls;
- Design of demolition and complete reconstruction with independent reinforced concrete structure of a portion of the building adjacent to the existing production plant;
- Construction of a staircase and elevator, with independent reinforced concrete structure, inside a portion of the existing production plant;
- Construction of a new deck on the 1st floor of a portion of the existing building, made with metal structure and floors in sheets collaborating with concrete casting and prior demolition of the existing floor.
The structural design was carried out in compliance with the Ministerial Decrees of 1996 relating to Technical Standards and Seismic Standards. However, given the imminent entry of the new Technical Regulations, it was considered appropriate to introduce some concepts of seismic design also already present in the circular Min. LL.PP. of 10.04.1997, n. 65/AA.GG not binding. This choice has resulted in the following actions:
- Application of the limit states method;
- Application of anti-seismic criteria on reinforcements and geometries in relation to: minimum quantities, construction and distribution criteria of the stirrups, geometry of the beams (limitations for beams in thickness), limits on planimetric eccentricity between beam and column axes, control of the failure modes of beams in ductile field;
- Total independence of new structures from existing ones through the insertion of seismic joints appropriately sized.
The structural analysis and the current verifications on the structural elements have been carried out using the Win-Strand calculation code produced by ENEXSYS S.r.L. Via Tizzano 46/2 Casalecchio di Reno (Bologna) and the post processors dedicated to the structures in reinforced concrete and steel named respectively WDisCa and Win AciVer, together with electronic spreadsheets specifically elaborated.
2. Foundation structures
According to the characterization of the ground, an inverted beam typology has been planned for the new buildings in order to contain the differential settlements. The geometry of the foundations was definitely influenced by the inclined trend of the longitudinal profile of the ground, the overall height difference is equal to about 4.30m and for this reason the vertical core of the inverted beams reaches heights greater than 2.50m, thus becoming real baffles. In order to realize the external accommodations are provided for retaining walls with heights varying from about 1.0m to 4.0m. The structures of the staircase and elevator inside the existing building are founded on slab.
3. Elevation Structures
The structures in elevation are generally constituted by spatial frames of beams and pillars in reinforced concrete which is entrusted with the function of resisting static and seismic actions.
The floors are of unidirectional type in pre-compressed slabs lightened with polystyrene blocks of variable spans from 8.0m to 6.0m, respectively for the new building and for the one to be rebuilt. All new structures in elevation are disconnected from the existing ones by seismic joints of variable thickness depending on the altimetrical quotas.
1. New building: the planimetric disposition of the structures is of rectangular shape with a footprint of 8.30×33.35m for a maximum height above ground of 12.50m divided by two intermediate floors and a ceiling. Two systems of seismic-resistant frame are foreseen, the first realized with two longitudinal frames of pillars and beams recalculated in correspondence of the perimeter infill walls, the second composed of eight transversal frames of pillars and beams in thickness of limited width according to the dimensions of the pillars.
2. Rebuilt building: The planimetric arrangement of the structures is rectangular in shape with a footprint of 7.65×12.20m for a maximum above-ground height of about 5.50m divided by a raised floor compared to the current ground level and a covering floor. The raised floor directly weighs on the cores of the foundation beams.
3. New metallic deck: the structure has plan dimensions of 11.30×8.0m, composed of HEA profiles with maximum spans of 8.0m. These profiles have been doubled and equipped with calastrons in correspondence of the central beam and edge on the border with the new wing. The secondary beams have a maximum span of about 6.10m. Inside the deck will be obtained the opening necessary to accommodate the stairwell and elevator. The floor of completion will be the type of corrugated sheet and concrete casting collaborating with a total height of 130mm. The connections are all made with bolted unions to cut while the connections to the pillars in c.c.a. existing are made through special saddles equipped with heavy anchorage systems on c.c.a. by means of chemical bars M20 through equipped with counter plate.
4. Stairwell and elevator: the structures in elevation consist of beams and pillars supporting ramps and landings of the stairwell and the box structure of the elevator shaft. The planimetric disposition of the structures is of rectangular shape with a footprint of 4.55×4.80m for a maximum height above ground of 6.80m at the head of the elevator shaft.