WAN AWARDS 13 Transport

Scale Lane Bridge on River Hull in full swing

An innovative swing bridge over the River Hull has opened to the public, offering pedestrians the unique experience of riding on the bridge as it opens and closes to river traffic, believed to be a World’s first.

The black steel bridge has a distinctive robust character and curving form, making it a memorable landmark that is unique to Hull and its industrial and maritime heritage.

The winning entry in an international 3-stage design competition held in 2005, the bridge has been built to the original concept by the competition team, main contractor and M&E engineers Qualter Hall, architects McDowell+Benedetti and structural engineers Alan Baxter Associates. The scheme includes a new landscaped garden and square designed by landscape architects Grontmij with lighting by Sutton Vane Associates and an integrated public artwork by Nayan Kulkarni.

Located in Kingston upon Hull east of Hull city centre the bridge connects Hull’s Old Town Conservation Area to the undeveloped industrial landscape of the east bank. Designed as the first stage of a wider masterplan it will unlock the potential of the riverside to promote wider regeneration in the areas east of the city centre. Scale Lane Staith on the west bank has been re-landscaped with a series of stepped gardens leading to a new public square at the threshold of the bridge. The bridge provides a walkable route connecting the Museums Quarter on the west bank to Hull’s major attraction The Deep.

The River Hull has a tidal range of almost 7 metres and has exposed mud banks on the west side. The 16 metre diameter drum of the bridge sits snugly into the raised river bed on the west bank and cantilevers 35 metres over the water to the east side. The spine of the bridge arches up and over the river, allowing enough room for smaller boats to pass under without need to operate the bridge, and rotates using an electrical drive mechanism to open the route to river traffic when required.

The bridge’s sweeping form creates two generous pedestrian routes, one gently sloping and a shorter stepped walkway. The roof of the drum provides an upper viewing deck with a seamless steel balustrade, which gives the feeling of being on board a docked ocean liner.

The central structural spine of the bridge includes seating areas, creating a variety of places for people to pause on route to relax and enjoy the riverscape views. The spine rises into a back-lit rooflight which provides a marker for the bridge at night.

When activated the mechanical movement of the bridge is sufficiently slow to allow passengers to safely step onto the bridge from the west bank whilst it is rotating.

Artist Nayan Kulkarni has created a public artwork on the bridge, a sonic landscape in which to enjoy the riverscape. When the bridge opening is activated a new sequence of rhythmic bells is triggered which increases in urgency and combines with a pulsing light developed by lighting consultants Sutton Vane Associates. This has a practical purpose in alerting pedestrians to the imminent opening rotation and it heightens the drama of the ‘ride’.

At night low level fluorescents integrated into the parapet posts light the profile of the bridge and bring colour and sparkle to the blackened industrial riverscape.

Hull City Council is now actively seeking a tenant to occupy the restaurant space in the bridge hub. Once in place Scale Lane Bridge will become a lively animated public place at all times of the day, fulfilling the design team’s intention to create more than just a crossing but a destination in its own right.

At the official opening on 28 June 2013 Councillor Nadine Fudge, Lord Mayor of Hull and Admiral of the Humber, said:
“It’s an honour to open this unique footbridge on behalf of the city, which links the Old Town to the east banks of Hull. Our Old Town has wonderful museums and attractions and it’s great that we’re able to add another experience for people to enjoy. Hull’s strong maritime history is echoed in the ships bells ringing as the bridge opens and we should be proud that we are continuing to reflect on our heritage.”

Jacquie Boulton, Area Manager at the Homes and Communities Agency said:
"The opening of this bridge gives the city an excellent opportunity to connect the east bank of the river to the city centre creating opportunities for new economic development. It is great that we have been able to work with our partners to create a bridge that is not only useful to local residents and visitors to the city but is also such a fantastic design."


Project credits:
Main Contractor: Qualter Hall
Architect: McDowell+Benedetti
Structural Consultants: Alan Baxter Associates
M&E Engineer: Qualter Hall
Lighting Consultant: Sutton Vane Associates
Landscape Architect: Grontmij
Public Art/Sound: Nayan Kulkarni, NK Projects (UK) Ltd
Civil Design: HBPW LLP
Civils - Bridge: A Torn Construction
Civils - Landscaping: Jackson Civil Engineering
Photos: © Timothy Soar


Structure
The structure consists of a steel spine cantilevering around from a 3-dimensional braced ring structure approximately 16m in diameter. The spine is a hybrid structure with the ‘root’ section conceived as a diagrid/shell structure and the tip as a shell structure. Steel plates clad the surface of the walkways whilst horizontal bracing provides additional longitudinal stiffness.

The ring/drum/hub structure consists of columns connected to horizontal steel “wheel” structures forming both levels of the 3D ring. The circular hub section acts as a counterbalance to the cantilever section, with heavy RC slabs at both levels of the 3D ring structure. Braced frames provide stability of the ring structure.

The hub is supported vertically on a central pintle and six single / four double wheel assemblies running on a 16m diameter flat circular track, secured to a concrete drum supported on ten 1.6m dia. piles over 30m long.

Mechanical operation
The bridge is supported on a series of wheels running on a circular 16m diameter track below the hub, like a railway turntable. Three electric bevel gear units drive the bridge which pivots around a central slew bearing.

The bridge is operated from a radio pendant. The whole sequence takes around 2 minutes. The bridge operator closes a gate at the East bank triggering the opening of the bridge. There are no barriers at the west bank so people can freely walk on and off while it is in motion. The speed of rotation at that edge is slow - less than 0.15m/sec, (less than half the speed of the London Eye) so can be stepped across safely.

Lighting
Sutton Vane Associates were commissioned to design the lighting for the bridge and the landscaping at both ends. The lighting provides functional and energy efficient illumination of the deck of the bridge by specially designed small fittings that are integrated within the balustrade. These fittings were designed to deliberately allow a little light out over the water so at night the shape of the bridge is defined by the points of light from the line of fittings. On the fin of the bridge Sutton Vane Associates designed tiny points of light that emphasise the shape and which come on when the bridge moves. Around the joint between the bank and the bridge is a row of recessed lights which also spring into life when the bridge moves. The lighting adds to the drama when this extraordinary structure moves.

Landscaping
The west bank of the bridge, which leads to the Old Town and is part of the Old Town Conservation Area, has been re-landscaped by Grontmij. A car park along Scale Lane Staith has been replaced with a series of informal ‘garden rooms’ stepping up to the river side.(with its increased flood defence level) and leading to a new paved square which will eventually provide space for al fresco seating for the restaurant. The original cobbles of the original staith have been retained and re-laid. A green wall of planting will provides a cohesive edge and screen the adjacent building once it matures.

On the east bank, pending future redevelopment of the riverside site, a temporary ramped path has been laid which orientates pedestrians to Hull’s main visitor attraction The Deep.


Public Art: ‘From Mizzenmast to Sandstroke’
In July 2008 Nayan Kulkarni won the commission to create an integrated public art work on the site of the bridge. ‘From Mizzenmast to Sandstroke’ is a light and sound installation developed by Kulkarni in collaboration with Shauna McMullen. Bronze strips measure out the space and incorporate the sparkle of back-lit text naming the parts of an historical merchant ship. Speakers concealed in the bridge seating and throughout the west bank play a range of sounds including birdsong, creating a gentle and varying spatial soundscape.

When the bridge is due to open the light and sound installation switches to an opening sequence to signal the rotation. Rhythmic bells and a pulsing light, designed by Sutton Vane Associates, emanating from the roof light fin and LED lights embedded in the bridge path serve to alert pedestrians to the imminent opening without recourse to a conventional ‘keep off’ hazard light and sound warning system.
The activity climaxes at the moment the movement begins, continues during the movement cycle and subsides as it comes to a stop.