Essential Maintenance On Humber Bridge Completed

VolkerLaser has completed essential maintenance works on the Humber Bridge, acting as the principal contractor for the Humber Bridge Board.

The bridge, which opened in 1981, is notable for being the UK’s longest single-span suspension structure, measuring 2,200m in length and standing 30m above the River Humber. It is a Grade I Listed structure, characterised by its two 155m-high towers designed with a remarkable precision to accommodate the curvature of the Earth, with their tops positioned 36mm further apart than their bases.

The maintenance project began with a detailed inspection of the central bolted splice on each gantry, carried out by rope access teams. Following inspections, the gantries were then transported to predetermined locations using a sophisticated combination of tirfors (winches) and rigging systems. A lift cradle was installed under each gantry, facilitating their safe lowering, which commenced with the Hessle Side span. The gantries were secured onto trestles before moving on to the Barton Side Span, which was lowered and dismantled with the help of an excavator wielding hydraulic shears.

Significantly, the lowering of the main span gantries involved a 35m by 11m barge accompanied by two tug vessels, highlighting the intricate planning and coordination necessary to align operations with the morning high tide. This phase required close collaboration with various parties, including the Port Authority, marine contractors, crane hire firms and salvage yards, while carefully considering weather conditions and tidal variations throughout the project.

The scope of work included the relocation and removal of four underdeck inspection gantries. Specifically, the Hessle Side Span gantry was moved approximately 280m and lowered for storage at the north anchorage compound. The Hessle Main Span gantry and the Barton Main Span gantry were each moved into the estuary and lowered onto barges for transportation. In the south anchorage compound, the Barton Side Span gantry was transported 530m, where it was dismantled and disposed of properly.

Despite the challenges posed by operating in a busy shipping lane with a 5m tidal range, the maintenance team successfully executed the gantry relocations and removals within tight time constraints. To limit disruption, operations were conducted from one side of the bridge’s footpaths, with the east footpath generally closed to the public. However, traffic on the bridge’s carriageway remained unaffected, ensuring a continuous flow for vehicles and pedestrians alike.

VolkerLaser reported that the project was completed on schedule and within budget, reinforcing the importance of routine maintenance for such a critical infrastructure asset.

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