Global crane manufacturer, Manitowoc, has supplied six Potain cranes to German construction giant, Max Bögl that is constructing a new bridge in Germany from the A3 freeway near Limburg. Working over some breath taking views of more than 230 ft. (70 m) high, the cranes tower over Lahn Valley.
The cranes for this project were supplied by Max Bögl’s subsidiary company, Max Bögl Transport & Geräte GmbH & Co. KG. Three topless Potain MDT 222 with tip heights up to 250 ft. (76.2 m) and a radius up to 197 ft. (60 m) were deployed. Two of them are mobile and one has been erected stationary. In addition, a stationary Potain MD 150 with a tip height of 98 ft. (29.8 m) and radius of 180 ft. (55 m), and a Potain MD 235 J12 crane with a tip height of 116 ft. (35.4 m) and a radius of 180 ft. is on site. Also, a topless Potain MDT 268A J12 with a tip height of 207 ft. (63.1 m) and a radius of 197 ft. (60 m) has also been erected moveable and is being rented from Manitowoc’s fleet for 15 months.
Enormous repair and maintenance costs necessitated the construction of the new Lahn Valley bridge, which involves rerouting the freeway. Additionally, the new structure will be designed with a noise barrier. The foundations of the new bridge are classic bored pile foundations but the abutment head will be poured, so two auxiliary piers are needed for this. They will be erected by a slip form method next to the future structural piers and after completion of the abutment head, two shoring structures will be built on it.
The new track is being created step-by-step in both directions and every week 16 ft. (5 m) long track sections will be built, utilizing the free cantilever method. As soon as the track towards Cologne has been completed, the Potain cranes and auxiliary piers will be shifted sideways for the same task, constructing the second bridge’s superstructure.
For the track towards Frankfurt, the cranes will be moved on a rail system. The auxiliary piers weighing almost 500 t on steel skid ways and plain bearings, utilize a hydraulic shifting system.
"Due to the special job site conditions here with a busy freeway and a railway at the south shore, all cranes had to be equipped with an operating limit system,” says Herbert Wieseckl, department manager for structural engineering technology at Max Bögl Transport & Geräte.
Selection of the crane specifications had to be taken into account because of the frame work weighing up to 8 t, which was supposed to be transferred across the Lahn River to the next crane. For the same reason, mounting heights allowing overlapping swivel movements had to be selected.
Deployment of the V63A undercarriage, a reinforced version of the V60, was necessary in order to achieve the free-standing tip heights and related capacities. Up to the first tower section, the V63A is higher than the V60, therefore it can handle 180 t of ballast instead of 132 t.
“At such tip heights, the load duty cycle performance is important,” says Manfred May, site manager in Limburg. “Therefore, the cranes have been equipped with the high performance 75 LVF hoist and all cranes have a rescue system from heights. Each crane operator has been trained for this to ensure safety. Also, concrete pumps can only be utilized up to a certain construction height so some concreting work was done by the cranes. With Potain cranes, we could pour up to 18 m³ of concrete an hour. That's quite an accomplishment.”
Enhancing the reliability of Potain cranes, the manufacturer's Manitowoc Crane Star division offers a remote diagnostic tool, which provides online readouts of error messages enabling the operator to correct faults in advance.
“Another important aspect of this construction site is the temperature, because now the authorities prohibit working at temperatures exceeding 38 oC,” adds May. This validates Potain's decision to design all cranes with air conditioning as standard equipment.
The old Lahn Valley bridge was built in 1964 and is about 1,300 ft. (400 m) long and almost 200 ft. (60 m) high, according to the Federal Highway Research Institute. Its daily traffic volume exceeds 100,000 vehicles, which makes this bridge one of the most heavily used bridges in Germany. The old Lahn River bridge was beyond saving and after completion of the new bridge, the old one will be demolished.