Online exclusive - Air springs lift the roof

Air springs from ContiTech, Hannover, Germany, play a key role in building modern hall constructions. Montur, a Spanish company specializing in industrial constructions, has developed a construction design for large halls in which the roof construction is first laid out on ground level and then raised in one piece by synchronized pneumatic pillars. Air spring systems from ContiTech ensure that the roof construction remains level at all times during the process.

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Compared to conventional beam and trellis designs, the hall design created by Montur presents considerable benefits. Construction time is reduced by a third and the construction itself has become much safer. Also, industrial installations such as lighting, air-conditioners, or fire extinguishing systems can be fixed to the roof before it is raised. First, the self-supporting roof construction is built, and then the roof is raised slowly. The lifting device is composed of a varying number of synchronized pneumatic pillars. Each pillar consists of fixed column elements, mobile column elements and a pneumatic system with four air springs. A hydraulic system regulates the tension of the mounting brackets and a controlling device that monitors the synchronization of the pneumatic pillars.

Each pneumatic pillar can carry a weight of 100 ton. Its modular construction allows for a levitation height up to 38 m. For that matter the pillar is lifted by 400 mm by air springs from ContiTech and step-by-step expanded by further column elements.

"The task of lifting is carried out by the very strong FT 5450-44 triple convolution air springs from ContiTech. During construction, each supporting pillar rests on four air springs. All of the air springs are then inflated synchronously with compressed air, and the entire construction is lifted uniformly," explains Mariano Alvaro, product manager at ContiTech in Spain. Since the bellows don’t contain a piston rod, the entire construction is very space saving. The minimum block height of e.g. type FT 5450-44 is 140 mm.

For a 10,000-square-meter factory hall, the load per air spring is 25 ton. Once the roof has reached the proper height, the pneumatic pillars will be replaced by conventional ones. During construction, the air springs can be subjected to all sorts of weather conditions. They are resistant to water, oil and other materials, and are also maintenance free.