Vibration measurement and location determination of a gravimeter in the GeoSN
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Project data
| Titel | Title Schwingungsmessung und Festlegung eines Standortes für ein Gravimeter im GeoSN | Vibration measurement and location determination of a gravimeter in the GeoSN Auftraggeber | Client Staatsbetrieb Sächsisches Immobilien- und Baumanagement, Niederlassung Dresden Zeitraum | Period 05.2013 – 06.2013 Leiter | Project Manager Prof. Dr.-Ing. Dr.-Ing. E.h. Manfred Curbach (Institut für Massivbau, TU Dresden), Bearbeiter | Contributors Dipl.-Ing. (FH) Sabine Wellner, Heiko Wachtel, Dr.-Ing. Torsten Hampel |
Report in the yearbook 2013
Vibration measurement in GeoSN
Accelerometer applied to the floor
For the determination of the location of a gravimeter in the State Enterprise for Geographic Information in Dresden GeoSN, the Otto Mohr Laboratory was commissioned to measure the influence of the existing traffic and the vibrations registered within the building. For this purpose, vibration measurements were carried out in a total of five rooms.
In general, vibrations or shocks in buildings are always transmitted if there is no decoupling between the individual building components. This can result in damage to the building, among other things. The gravimeter available in GeoSN is used to calibrate other gravimeters, so its data is used to determine how much deviation there is from the nominal position in other gravimeters. Thus, even the smallest vibrations in the tenth of a millimeter range are important for determining the position of a gravimeter.
Static accelerometers were used to measure the vibrations transmitted through the floor of the room in both the horizontal and vertical directions over a period of seven days at a measurement rate of 200 Hz. Spring-mass accelerometers with a measurement range of ±3 g were used for this purpose. A total of around 1.45 billion values were recorded. Depending on the location of the room within the building, different levels of vibration were detected. Subsequent comparison of the accelerations measured in the individual rooms made it possible to determine the most suitable location for the gravimeter including base.
Basically, however, the measurements showed that none of the examined rooms is free of vibrations, since more or less large and more or less frequent vibrations were measured everywhere. To achieve decoupling of the base from the floor slab, the floor under the base would have to be separated with a circumferential joint by saw cuts and sealed with a highly damping material. Another option is to use a damping platform that separates the vibrations from the gravimeter. In this way, an object can be dynamically decoupled from its environment and the transmission of vibrations and structure-borne sound can be reduced. Isolation is achieved by installing elastic materials or components, such as passive diaphragm air springs, air bearings or active vibration isolation systems.