Scale Lane Bridge, Hull

Structural Steel Design Awards 2014 - Commendation

This innovative swing bridge over the River Hull is believed to be the first bridge in the world that allows pedestrians the unique experience of riding on it while it opens.

Its black steel appearance and distinct robust form make it a memorable landmark that reflects Hull’s industrial and maritime heritage.

With a 57m span, the 1,000t pedestrian and cycle swing bridge provides a new route that connects the city centre and Old Town Conservation Area to The Deep on the east bank of the River Hull.

The client’s brief was for a bridge that would become an iconic landmark, increase connectivity across the city, unlock regeneration potential and increase the use of the river frontage. The brief also required navigation clearances to be maintained at all times for small boats and the bridge to be able to open for larger vessels.

The bridge’s sweeping form creates a choice of two curving pedestrian routes – one gently sloping, the other stepped. The circular geometry of the bridge’s hub means the walkway is always in contact with the river’s west bank as it swings open, allowing people to walk on and off as it moves.

The structure can carry up to 1,000 people while opening and up to 4,000 people when closed.

The use of steel has allowed the design to incorporate the sweeping curves developed by the architect, while retaining the inherent strength of the steel plate required within the structural design.

Structurally, the bridge consists of a curving steel spine cantilevering from a three-dimensional braced ring that is approximately 15m in diameter. The spine is a hybrid structure with the root section conceived as a diagrid/shell and the tip as a shell. Steel plates clad the surface of the walkways while horizontal bracing provides additional longitudinal stiffness.

The hub structure consists of columns connected to horizontal steel wheel structures forming both levels of the three-dimensional ring. The circular hub section acts as a counterbalance to the cantilever section, with concrete slabs at both levels.

It is supported vertically on a central pintle and six single and four double wheel assemblies running on a flat circular track, secured to a drum supported on 1.6m diameter 30m long piles. Three electric bevel gear units drive the bridge which pivots around a central slew bearing.

The bridge was fabricated in sections at Qualter Hall’s works using temporary support jigs to replicate the finished shape, and trial assembled before transport to site.

On site, the sections were welded together to form the whole bridge structure before being lifted into position in a single operation.

Architect	McDowell+Benedetti
Structural Engineer	Alan Baxter & Associates
Steelwork Contractor	Qualter Hall & Co Ltd
Main Contractor	Qualter Hall & Co Ltd
Client	Hull City Council

Judges' comment

This swing bridge over the River Hull offers the memorable experience of riding on the bridge whilst it opens. The judges appreciated the high quality detail and fabrication of the hybrid spine structure, which forms the sweeping shape.

The team successfully integrated a number of complex mechanical, electrical and structural components into this unique rotating structure.

The bridge is greatly enjoyed by the public.