One of the largest video modules in Europe is suspended in Bucharest and held in place by Demag hoist technology. Weighing some 36 tonnes, the multimedia element is integrated into a wire rope suspension system that is installed above the new national stadium in the Romanian capital. Four Demag rope hoists and Demag drive components help to ensure that the video module can be lowered and lifted again safely and precisely depending on the needs of the event.
Responsible for the development, planning and installation of the video module is the S[quadrat] GmbH company, based in Schwanstetten, Germany. “For the project in Bucharest, we looked for and found a partner with a proven track record of technical expertise and experience in the implementation of comparable solutions”, explains Mark Siedentopf, General Manager of S[quadrat]. The company has grown to become a leading supplier of multimedia information systems. “Demag Cranes also provided us with good advice on safety and efficiency. Precision, time management and logistics were specified and delivered.”
The state of Romania and the city of Bucharest invested some EUR 140 million in the construction of the new national stadium “Arena Națională”, which was officially inaugurated at the beginning of August 2011. The arena, which measures 210 meters long and 190 meters wide, can accommodate 55,000 spectators and is the largest football stadium in the country. It will also host UEFA Champions League games. The video module, which is 11.5 meters wide, 9 meters long and 9.2 meters high, is installed above the center of the playing field. Visitors to the stadium can follow events on the pitch in high detail and perfect image quality on four 32-square meter displays.
Dr. Thomas Bönker, Head of Components at Demag Cranes, states: “We had already realized a similar project at the Commerzbank Arena, the former Waldstadion in Frankfurt am Main, Germany. The experience we gained there was valuable and enabled us to manage the many challenges resulting from the tight schedule to the satisfaction of all concerned.”
Special coupled hoist unit
Depending on the wind and weather, the interior roof over the arena – a membrane structure incorporating steel wire rope – can be opened or closed within 15 minutes. For this purpose, the video module is first lowered several meters by the four Demag hoist units, each of which is rated for loads of 18 tonnes, and therefore twice their rated capacity. The module is subsequently raised again to its parked position. Thanks to the use of frequency inverters, the lifting and lowering speed can be infinitely adjusted between 0.5 and 5 meters per minute.
In addition, Demag Cranes supplied the hoists as parallel units featuring a coaxial coupling arrangement. This ensures that the hoist units perform synchronized operating motions and that parallel motions are possible in the vertical direction.
Maximum possible hook path required
The four Demag DH hoist units, which are rated for a total load capacity of 36 tonnes, are driven by two Demag ZBA cylindrical-rotor motors and have been specially prepared for operation outdoors. To achieve a maximum possible hook path, Demag Cranes employed special rope drums with a high-strength wire rope that is specially optimized for this application. Consequently, a hook path of 41.5 meters was achieved thanks to the use of ropes with a diameter of just 16.2 millimeters. This arrangement also makes it possible to lower the video module to a point where it can be reached for maintenance purposes from the pitch.
Lower maintenance requirement, lasting cost reduction
S[quadrat] followed recommendations by Demag Cranes when it decided to employ coupled rope hoists as the lifting solution for the video module. Arguments in favor of this solution included its compact design, its long hook path and the high availability of the hoist units. In addition, only four rope hoists rated for higher load capacities and two motors are sufficient to hold the weight of the video module and to handle it safely. As a result, the maintenance requirement is also reduced. On balance, this is also reflected by lower costs both for the procurement as well as for operation of the video module.
Specification according to BGV C1 safety regulations
The rope hoists had to meet special project engineering requirements according to BGV C1 accident prevention regulations for event and production facilities for stage presentations. This means that unlike normal industrial applications, the rope hoists had to be designed and adequately rated for special hazards and loads that occur during this type of operation. This due to the fact that people who have to be present beneath the load, which weighs many tonnes and seems to be suspended in mid air, must not be exposed danger under any circumstances. Demag DH 1000 rope hoists meet the requirements of this regulation, also thanks to their safety factor of 10 with reference to the calculated breaking force.
In addition, Demag Cranes equipped the rope hoists with special holding brakes and, therefore, satisfies the BGV C1 regulations for the mechanical components. Limitation of the lifting range is provided by operating limit switches. An electronic load detector integrated into the return sheave ensures that the system is automatically switched off when the rated load capacity is exceeded by a factor of 1.2.