Elastic Support of Power Plant Equipment

Floating Floors

GERB offers elastic systems consisting of helical compression springs and damping elements to protect power plant buildings and technical equipment from exposure to low frequent destructive vibration.

The following mechanical and natural excitation mechanisms pose the risk of damage to power plant buildings or technical equipment

  • power plant machinery like coal mills, blowers, pumps and turbines produce quantifiable periodic mechanical forces, vibration and structureborne noise;
  • sudden impacts like earthquakes or aircraft crashes and
  • creeping incidents like soil settlements

Furthermore an impairment to the work force’s perception, health and work performance can be expected.
Mechanical forces caused by machinery should be reduced directly at the source but in some cases secondary measures are inevitable

GERB Floating Floor Systems are using mainly two kinds of spring elements:

Embedded “jack up” Spring Elements
Embedded in the concrete slab, jack-up type spring elements are the preferred choice in terms of simplified installation, high flexibility / re-adjustability and low system height.

Supporting spring elements
Supporting spring type elements are arranged below the floating slab or the complete control room; they are designed to carry high loads and can easily be adjusted to actual loads.

Both systems protect power plant buildings, technical equipment and plant staff against low frequent vibration and structureborne noise from the surrounding over the plant’s lifetime.


Technical characteristics of the GERB Floating Floor Systems:

  • Different springs are available to provide system natural frequencies between 2.5 - 7 Hz ensuring best vibration isolation. The system is adapted to the specified requirements and decouples e.g. main control rooms from the base foundation
  • Springs are accessible and can be replaced to match different load capacities or to compensate soil settlements
  • Slab leveling is achieved with different spring element types and/or load capacity -combined in a system layout that addresses irregular slab loadings
  • Slab construction and installation of the spring elements is very simple for both types
  • Especially for earthquake endangered regions the spring elements can be equipped with a damping system in order to stabilize the floating slab and improve the vibration performance at higher frequencies
  • The minimum slab thickness for “jack-up” installations is 125 mm
  • Acoustic pads below the steel spring housings reduce transmitted structureborne noise.

Please find hereafter some sketches / photos showing the installation of the “Jack-up” spring system – this system is decoupling the floor.

Cross section of the “jack-up” spring element

Rebars for slab arranged with housings placed

Concrete has been poured and levelled - cover of housings still visible


“Supporting spring systems”, as shown below are used to elastically support complete Main Control Rooms (MCR). A major benefit is that the MCR can be built outside the power plant area at reduced costs and independent of ongoing construction work. After completion of the foundation and the spring system installation, the complete control unit will be positioned on top of the spring elements.
The same system can also used to elastically support complete Power Plant Buildings / Nuclear Islands. The “supporting spring” system has been widely used in existing Nuclear Power Plants to decouple control rooms from damaging effects described above.

Cross section of the “Supporting Spring Element System”

Spring element placed on concrete deck

Steel construction placed on spring elements - still accessible


Many power plants have been equipped with these systems. Please ask for our reference list.

Scope of GERB Services

  • Technical consultancy from GERB vibration isolation experts;
  • Vibration measurements and evaluation according to engineering standards and specifications;
  • Support to prove the system’s “warranty of fitness” for power plant applications;
  • Selection of appropriate floating floor systems meeting specified requirements;
  • Full civil engineering design from Lay-Out - to Formwork - and Reinforcement Drawings;
  • Design, manufacture, test and supply spring elements and accessories;
  • Installation of system or supervision on behalf of contracting party;
  • Technical support from engineering to installation and final functional approval;
  • Conduct inspections.

All activities are carried out in close contact with the contracting party, structural engineers and architects.
Similar applications of floating floors are possible for residential buildings or offices and more details are available here Building Isolation.