Location: Milan, Italy
Market: Façades & Cladding
Product: Hollo-Bolt^® by Lindapter
Quantity: 6,800
Contractor: MAP Carpenteria

The Isola district of Milan has recently undergone a major transformation, making it one of the most attractive areas of the city. Due to the prime location of De Castillia 23 and its excellent transport links, Gruppo Unipol decided to renovate the building and occupy it as their headquarters. 

Unipol wanted to create an innovative, contemporary building in keeping with the area. The restoration work aimed to completely change the building’s aesthetic features, but also to improve its functionality, energy performance and the overall efficiency of the building’s management.

The architects, Progetto CMR, proposed an unusual glass prism façade design, aimed at reflecting sunlight in a constantly different way. This required a method of connecting the glass support brackets to the hollow tubular sections forming the façade.

The structural engineer for this project decided to specify the Flush Fit Hollo-Bolt by Lindapter, an expansion bolt that requires access to only one side of a Hollow Structural Section (HSS).

Hollo-Bolt was chosen as it offered significant benefits including fast installation, high strength capacity, clean visual finish, and a range of independent technical accreditations, which include the CE mark and ETA to achieve a design compliant with Eurocode 3.

The main contractor MAP Carpenteria used a total of 6,800 size 5/16" Hollo-Bolts to connect the glass support brackets to the façade framework of two buildings. Installation was quick and easy as each bolt is simply inserted into pre-drilled holes and tightened with a torque wrench to recommended tightening torque to provide the necessary clamping force. The brackets then securely held each glass panel in the required position to create the elegant façade.

The specification of Hollo-Bolts provided an approved connection design compliant with Eurocode 3 that met the structural engineers requirements.

Hollo-Bolts also provided a clean architectural appearance, due to the flush fit head type, and excellent corrosion protection thanks to the zinc plated finish.

• Fast, cost saving installation from one side
• Suitable for square, rectangular and circular hollow sections
• High resistance to shear and tension
• Unique high clamping force design