§ DWG-005 · the building
One line across the harbour.
The inlet at Bjørvika had been crossable only by ferry or a long detour up the eastern arm of the harbour. The brief, from the Oslo municipality, was for a single-span bridge carrying a light-rail line, two cycle lanes, and a generous pedestrian deck — built within thirty months and assembled without disturbing the shipping channel below. We answered with a Warren truss in S355 weathering steel, fabricated off-site in two halves and floated into position on a single November tide.
The truss is the bridge. No suspension cables, no arch, no separate parapet — the diagonals do the parapet's work, and the deck slips through the truss web at the third-points. Members are box-section, 1.2 m × 1.6 m at the chord, hot-rolled S355, with site welds at the splice points only. The bridge weighed 4,200 tonnes when it floated; six tugs walked it from the fabrication yard at Verdal to Oslo in three days.
The pier foundations are 6-metre-diameter cast-in-place concrete on driven steel piles that reach bedrock at −18 metres. The light rail opened across the bridge in December 2020, eighty days after the float-in. The Norwegian Steel Prize followed the next spring.