Architect: Gerkan, Marg and Partners (GMP)
Type of works: supply and installation of Lindapter's Hollo-Bolt^® Flush Fit structural steelwork connection.

Lindapter’s new Hollo-Bolt^® Flush Fit was specified as a structural steelwork connection in HafenCity’s Brooktorkai quarter, securing a wide spanning glass roof and multi story windowed front without the fixings being visible. The revolutionary Hollo-Bolt creates immense opportunity for architectural design as the unique fixing is concealed within the steelwork with no protruding bolt head or nut.

Architect GMP (Gerkan, Marg and Partners) designed the Brooktorkai quarter utilising clinker-brick facades as a reference to nearby historic buildings, while marrying with clean, modern lines of large glass enclosed open spaces. The prominent glazed feature of the Germanischer Lloyd building guarantees expansive views over the old warehouse district and creates a striking entranceway to the company’s new head office.

The Lindapter M12 Hollo-Bolt Flush Fit was used to construct the glazing support frame with a connection design that included splice joints inside the adjoining pre-drilled SHS sections, allowing the fixings to be simply inserted and tightened with a torque wrench for a rapid installation. The cost-effective solution required no specialist equipment or labour and dramatically less work at height in comparison to traditional welding or through-bolting methods. The resulting steelwork is not only structurally sound, but aesthetically pleasing, presenting a clean symmetrical appearance.

Lindapter’s latest innovation merges the technical advantages of its distinguished Hollo-Bolt with the aesthetic benefits of a discreet fixing. The Hollo-Bolt is independently approved as a primary structural connection and is the only cavity fixing to feature in the SCI/BCSA joint publication ‘Joints in Steel Construction – Simple Connections’. Typical applications include: primary and secondary steelwork, cladding, balconies and staircases.