Rothoblaas: Our expansion under the banner of technological innovation (Sponsored content)

THE CONSTRUCTION SITE

The self-supporting warehouse, located adjacent to the headquarters, is located in the province of Bolzano, in the municipality of Cortaccia sulla Strada del Vino. The construction site is located in the former bed of the Adige River, which was reclaimed by Maria Theresa of Austria at the end of the 18th century in order to obtain land for agricultural use. This aspect had an important influence on the structural design of the foundation system, forcing the choice of a slab foundation, resting on drilled piles with a continuous helix, with a diameter of 40 centimetres and a length of 27 meters. The three hundred piles made are the roots of the forest above consisting of five hundred glulam columns, which support the shelving and the warehouse itself.

ARCHITECTURAL CONCEPT

The architectural and compositional aspects recall the choices made for the existing headquarters, which are characterized by large windows and a significant presence of timber, used both for structures and for flooring and coverings. Fire safety requirements, however, have imposed different solutions for the automatic warehouse. For this reason, the new construction will be almost entirely covered in aluminium, while the current sloping windows will be replaced by high-quality three-dimensional coatings made of larch strips, recalling the internal timber structures.

STRUCTURAL CONCEPT

The special feature of a self-supporting warehouse is that the shelves, which transfer the weights of the stored goods to the ground, also act as a load-bearing structure for the warehouse itself. The main challenge for such a structure is represented by the resistance to horizontal actions (earthquake and wind).

The warehouse is fitted with two independent bracing systems in the two directions: for the north-south direction (long side) twelve bracing towers consisting of a box section in LVL and glulam measuring 1 x 2.5 meters have been used. These are embedded in the foundation by means of plates pre-inserted in the poured concrete.

All the shelving is connected to the bracing towers to transfer the seismic forces onto them. In the east-west direction, the bracing system is constituted by the shelving itself, with the five hundred columns interlocked at the base and connected to each other only at the roof: the roof is constituted by a framework of glulam beams and CLT panels, which create a rigid diaphragm.

The main critical point of these structures is the deformability towards wind actions, which must be limited to allow the operation of the machines. In fact, the project includes a displacement at the top (at a height of 20 meters) of only 19 millimetres in the east-west direction and 12 in the north-south direction.

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SEISMIC SAFETY

The works, as mentioned above, are located in northern Italy, in an area classified as low seismic hazard. However, given the height of the building and the isostatic construction system, the design for horizontal forces (earthquake and wind) was particularly challenging. Therefore, a non-dissipative design was chosen, with a structure factor of 1.5 according to EN 1998-1.

Since the building adheres to the existing building, it was necessary to create a seismic joint to decouple the dynamic behaviour between old and new structures.

FIRE SAFETY

One of the major design challenges of the self-supporting warehouse was the structure's fire safety: various solutions were evaluated, including the use of an automatic sprinkler system, which was discarded due to the impossibility of having a sufficient water flow.

The final solution that has been adopted is therefore based on a fire resistance requirement of R30 for all the structures of the warehouse, which is relatively easy to achieve with properly designed timber structures. The R30 requirement also shifted the design of connections to solutions without exposed plates, using innovative timber-based materials instead of steel plates. Solutions with intumescent coatings to protect the steel were adopted where this was deemed unfeasible.

TECHNICAL DATA

• 3200 m2 of new storage area  
• 800 m2 for goods handling (entrance + sorting ramps) 
• 1200 m2 for new offices  
• Total dimensions of the construction 40x80m and 20m height
• 200 Kw/h photovoltaic system
• Bracing system consisting of 16 glulam GL24 and LVL (Laminated Veneer Lumber) combined towers
• Glulam shelving
• Structure fire resistance class R30