The first major steel section of Lowestoft’s iconic Gullwing bridge, has been moved into position over the East Suffolk rail line during a 52-hour possession which went seamlessly thanks, in part, to HBPW’s meticulous temporary works designs.
Suffolk’s much heralded £145m structure – also known as the Lake Lothing Third Crossing – is set to become one of the region’s most iconic landmarks when it opens next year, however, without certain engineering considerations the hugely successful project might have told a very different story.
HBPW Partner, Paul Monaghan said: “The operation required the use of Self-Propelled Modular Transporter units (SPMT), a vehicle composed of a platform supported by computer-controlled axles, in order to move the 20m x 60m North Approach Viaduct section – (NAV1) – into place. It weighed just short of 1500 tonnes.”
To avoid endorse lessons learnt on recent bridge installations using SPMT Transporters, HBPWs temporary works designs provided for an aluminium trackway, supported on top of ballast and timber matting, enabling the SPMT to seamlessly move the bridge section into place between Pier 7 and the north abutment at the northern end of the bridge.
“The solution was developed by mitigating risk and the threat of localised settlement under the SPMTs wheels,” added Paul. The operation began at midnight on Friday evening and concluded on Monday at 5am when the line was returned to Network Rail.
“As usual it was a combined effort by a raft of supply chain partners and, although highly complex, the project was delivered on time and to plan, testimonial to the intricate two-year planning period by a range of people including HBPW’s temporary works team.”
Stage 1 took place earlier when ‘NAV1’ had arrived at the construction site on a barge following a 32-hour crossing from Victor Buyck Steel Construction in Ghent, Belgium.
It weighed in at 380 tonnes and required the temporary assessment of existing quay walls, and the temporary works support, to allow the casting of the bridge deck which increased the weight to 1450 tonnes.
Challenging soil conditions required the design and installation of a large concrete raft foundation which limited temporary deflections associated with casting the bridge deck.
The Gullwing will not only open a host of economic opportunities in the region, but also reduce traffic congestion in the town, regenerate the area and attract new investment for the local economy.
Client: Suffolk County Council
Contractor: Farrans Construction