Innovative rail bridge launch by ALE

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Innovative Rail Bridge Launch at Key Interchange

ALE has assisted to replace two girder frame bridges built in early 1920s and install a new bridge at Duisberg Hauptbahnhof which is a busy interchange point.

The current bridge serves approximately 110,000 passengers daily and lies at the meeting point of many important national and international railway lines. Just north of this station, seven lines run to crossings of the River Ruhr.

The smaller of the two existing bridges was removed first, using Mega Jack 800 cassettes positioned on top of 6 axle, 4-file SPMT. During this operation, 15t of ballast weight was positioned on top of the bridge for stability.

The bridge was lifted from its bearings using the stroke of the SPMT, and a 75m transportation performed over rough terrain to an adjacent site. From here the 150t, 35m long structure was lifted in tandem by two 350t cranes to ground level, allowing it to be demolished.

The second, 450t bridge was then removed. To achieve this, a configuration of pontoons was prepared half a kilometre away, consisting of two stabilisation pontoons and a lifting pontoon equipped with the Mega Jack 800 system, winches and ballast pumps.

This flotilla was manoeuvred underneath the bridge using the winches, then the Mega Jack 800 was raised to a height of 10m, allowing it to lift the bridge from its bearings. Following transportation to the quay, the bridge was jacked-down to the fullest extent possible with the Mega Jack 800, and then, using eight 150t climbing jacks, to a total clearance of 0.6m between pontoon deck and bridge girder.

The combined height of all items was 10.3m, allowing the 75m long bridge to pass under the A40 highway en route to its demolition point.

The engineering expertise of ALE allowed the new bridge to be built just 75m from its installation site and then lifted a short distance into place, helping reduce overall disruption during the construction project.

Innovative Rail Bridge Launch at Key Interchange
Innovative Rail Bridge Launch at Key Interchange

From a starting position 1.5m from the ground, the 1,600t structure was lifted to 5.7m using four 500t climbing jacks. This allowed two sets of SPMT equipped with Mega Jack 5200 beams to be driven underneath the bridge structure, and then lift it using the stroke of the SPMTs.

Meanwhile, two pontoons were prepared with support structures 9.5m high, topped with four 650t cylinders each. The new bridge was driven towards the water’s edge until a sufficient overhang was in place to allow the first pontoon to be positioned underneath the overhanging section and take its weight.

From here, the bridge was launched over the water by driving the SPMTs forward, in so doing moving the pontoon across the water’s surface. Having been launched partway across the water, the second pontoon was floated into position, such that the weight of the bridge was borne entirely by the two pontoons.

A similar procedure was then performed, whereby the bridge was brought to overhang the opposite bank and was then lifted by SPMT there, positioned transversally to allow the bridge to be manoeuvred to the correct angle. Having been correctly oriented, the bridge was transferred to four 500t climbing jacks and jacked-down onto its final bearings.

The new structure is larger than both of those it replaced, measuring 135m x 8.25m x 16.65m.

The various lifts required differing equipment to complete. The smallest bridge required 12 axle lines of SPMT and 16 Mega Jack 800 cassettes to remove. The larger bridge required the main pontoon measuring 43.5m x 10.3m x 3m, two stabilisation pontoons of 30m x 3.5m x 3m, 40 Mega Jack 800 cassettes and eight 150t climbing jacks.

The installation phase required 80 axle lines of SPMT in challenging combinations and angles, two pontoons measuring 65m x 11.4m x 3.5m, four 500t climbing jacks and 36 Mega Jack 5200 beams.

This innovative launching methodology allowed the new bridge to be launched around many surrounding structures, utilising nearby infrastructure to provide a solution best suited to the local environment. Care was also taken to preserve important drainage canals and to protect soft verges through use of load-spreading equipment.

The new rail bridge installed by ALE has a working life of 100 years and will carry over four billion passengers over the Ruhr river in this time.

Source: ALE