ALE’S Mega Jack performs first jack-up in Europe17 August 2016 by Sotiris Kanaris
ALE’s Mega Jack system, engineered to push structures of staggering weights and sizes, has been used to jack-up the main bridge of a bridge heightening project in Genk, Belgium.
This was the first time the giant modular jacking system has been used in Europe. Each modular tower uses four 1,300t capacity jacks, for a lifting power of 5,200t per tower. The flexible design of the system means many tower can be used together: for example, a ten tower system can lift 52,000t.
On previous jobs in Europe, ALE has deployed the smaller but conceptually similar Mega Jack 800, which offers a capacity of 800t per tower, in a simple system designed for easy integration with other systems like this. Until this job, the much larger Mega Jack had mainly been put to use on oil and gas projects around the world.
Jacking-up the bridge sections was the first phase of Albert Kanaal project. The main bridge, with a span of 180m and weight of 4,500t, along with the two side bridges, weighing 536t each, were jacked-up 2.9m in three consecutive days.
Jos Baelemans, project engineer, said: “One of the challenges was to utilise a computerised jacking system with a jacking accuracy of +/- 0.3mm and a read-out accuracy of +/- 0.01mm. Furthermore, as the bridge foundations were located close to the quayside, a system was required with a high jacking capacity and a small footprint. Given the extreme weight of the bridge, we believe the optimum solution would be to use our Mega Jack System.”
For both side bridges, a computerised jacking system with a total of 2,000t capacity and oversized steel beams was used, which allowed for the bridge to be jacked-up on all 14 bearing points simultaneously.
Eventually, the height allowance of the bridge for ships to pass under was increased by 2.4m.
The bridge heightening is part of the Albert Kanaal Project, in which over 50 bridges will eventually have a free passing height of 9.1m to allow ships with four layers of containers to pass through the channel. Some bridges need to be completely replaced, other bridges only need to be heightened and some bridges already have the sufficient height.
ALE has also been awarded the contract to launch the new bridge at Zolder, weighing approximately 1,200t. This bridge is also part of Albert Kanaal project and the launching will take place in the autumn of 2016.