Two MDT 128 topless cranes from Potain are playing a crucial role in the construction of the Hardanger Bridge in Norway, set to be one of the longest suspension bridges in the world. The 6 t cranes are placing suspension cables, and making other lifts, at the top of one of the bridge’s pylons, where working heights exceed 200 m.
The cranes are owned by Ajos, a leading crane rental company and the Potain dealer for Denmark. Ajos supplied the cranes to MT Hojgaard, one of the largest contractors in Scandinavia. The company also provided two of its most skilled operators to the project, whose ability to control the lifts in harsh working conditions enables the job to keep moving ahead on schedule.
The exposed site means the Potain cranes have no protection from the harsh Scandinavian weather, where temperatures fall as low as –40˚C and wind speeds can reach up to 217 km/h. Such extreme conditions mean the cranes enter out of service conditions, but even when temperatures rise and wind speeds fall to acceptable levels for operations, maintaining lift schedules on the project remains a challenge. Work is continuing 24 hours a day on the job, meaning highly durable equipment is required, plus the latest lifting technology.
For the Hardanger job, the MDT 128 cranes have been fitted with Potain’s powerful 50 LVF GH Optima winch, and both are working with four falls of wire rope. This configuration allows the cranes to lift their maximum capacity, and also allows both high-speed hook operation and more precise movements when placing loads in their final position. The cranes are currently configured with 35 m jibs.
Assembling the cranes presented a challenge as steep valley walls lead down to the base of the pylon, and minimal space is available at ground level. The two Potain cranes were erected after the main support towers for the pylon had been built by an existing tower crane that was unable to climb any further. The cranes are located on a platform half way up the pylon, meaning that they cannot be reached from ground level and will have to be dismantled by helicopter.
Jørgen Egede Saabye, technical manager at Ajos, said the MDT 128s were performing well and have needed no attention aside from regular maintenance.
“We service the cranes every two months and they have the durability and reliability to handle the demanding workload in a very hostile environment,” he said. “This is a high-profile project on a tight schedule and when you’re working this high up, you need to have confidence in your equipment. With these MDT cranes we have that.”
Located over Hardangerfjord near Bergen in south-western Norway, the €300 million Hardanger Bridge will span 1,310 m – 20 m longer than the Golden Gate Bridge in San Francisco. Construction began in early 2011 and is scheduled for completion in 2013.