VIDEO: Bridge removal system on SPMT
16 February 2024
Airport bridge removal by Denzai deploying a jack up lifting system and SPMT. Alex Dahm reports.
Putting jack up lifting equipment on self propelled modular transporter (SPMT) made a mobile lifting system that allowed a project to be completed overnight with minimal disruption.
The Enerpac JS 250 jack up took the weight of the 150 tonne concrete bridge at it was cut through at each end, into a 21.5 metre long section before being moved away on the SPMT.
Denzai Engineering Corporation used an Enerpac JS 250 Jack up lifting system to remove a bridge at Narita City in Chiba, Japan. Removing the 150 tonne Shihongi #1 overpass road bridge was part of the preliminary work in preparation for a planned runway extension at Narita International Airport. Mounting the JS 250 towers on the Goldhofer SPMT meant the job could be done overnight in a 9 pm to 5 am window as quickly as possible with minimal traffic disruption on the busy Higashi-Kanto Expressway.
Extending Runway B at Narita Airport requires construction of a new grade-separated intersection between the Higashi-Kanto Expressway and the extended section of Runway B. It involves replacing 430 metres of the Expressway with a tunnel under the extended runway. Removing the bridge allowed the Expressway to be temporarily rerouted during the intersection construction.
The 150 tonne bridge would have been within the capacity range of a mobile crane but a shortage of space prevented the use of one. Denzai’s solution was to use the JS 250 Jack up system for its lifting capacity, stability and compactness, the company said.
How things stacked up
Two JS 250 towers were mounted on each of two rows of Goldhofer PST-SLE six axle SPMT modules side by side. A steel support platform placed on top supported the 21.5 metre long and 5 metre wide bridge deck as it was lifted and transported to a rigging location near the Expressway about 200 metres away.
Removal of the first bridge was followed on another night by a similar operation with the Shihongi Bridge #3, weighing nearer 500 tonnes.
On the move: Transporting the bridge 210 metres away to the off highway rigging location.
About the JS Series lifters
Several multi-point JS Series systems are available from Enerpac, including 125, 250, 500 and 750 tonne capacity models. Combined into sets of four towers, as they often are, with one under each corner of a load, gives total lifting capacities of 500, 1,000, 2,000 and 3,000 tonnes, respectively. More than four towers can be combined for heavier loads.
Each tower has four hydraulic lifting cylinders, one in each corner, powered by an electro-hydraulic power pack. The load is lifted synchronously using remote control in increments as dictated by the stroke of the cylinders. The void between the cylinders created as they lift is filled with steel ‘barrels’ like stillages. As the load rises these are stacked together to form lifting towers.
The barrels are sturdy structures weighing from 2.2 tonnes for the smallest (the JS 125) to 24 tonnes for each JS 750 barrel. Maximum lifting heights for the smallest and largest systems are six and 20 metres, respectively.
Only one operator is needed and the system actuates the lifting and lowering operations of all towers simultaneously.
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