Bumax selected by Skanska to supply fasteners for Stockholm lock project

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Swedish manufacturer of stainless steel fasteners Bumax has been chosen to supply high-strength and corrosion-resistant fasteners to global construction giant Skanska for the high-profile Slussen infrastructure project in Stockholm, Sweden.

Skanska has ordered approximately 15,000 premium Bumax fasteners for the Slussen infrastructure project in central Stockholm to be used on the new water lock’s sluice hatches.

The Slussen area in central Stockholm is being redeveloped with new stainless steel sluice and flood gates – to help the region cope with the anticipated sea level rise in the coming century. It is a massive and essential nine-year SEK 15.8bn (USD 1.6bn; EUR 1.3bn) project in the heart of Stockholm, one of the biggest infrastructure projects in Sweden in recent decades. It includes road and rail infrastructure as well as rebuilding the lock and sluice system and is expected to be complete in 2025.

The gates are among the largest of their type in the world and designed to resist corrosion in the brackish water environment over a 100-year lifespan. As they cannot be removed once they are in operation, their strength and corrosion resistance are of great importance. The gates simply cannot be allowed to fail during their long lifespan.

Skanska turned to Bumax to provide premium high strength and corrosion resistant stainless steel fasteners for the Slussen sluice hatches. The company ordered approximately 15,000 Bumax fasteners for the project. The fasteners specified were a mixture of Bumax 88 (A4/316L) and Bumax SDX 109 (Super Duplex), which are said to provide high strength and excellent corrosion resistance. This solution catered for conditions posed by brackish water from Lake Mälaren and also the higher salinity of the sea water from the Baltic Sea.

Around 90 different types of Bumax fasteners were ordered for the Slussen project. The largest of these fasteners were Bumax SDX threaded rods M48x1225 and M36x1125, in class 80.

Due to the size and strength of these largest rods, Bumax collaborated with RISE (the Research Institute of Sweden) to utilise specialist testing equipment, in order to test the mechanical strength of the fasteners. These tests showed that the rods could reach loads of 886kN prior to yield and 1,221kN on fracture.