engleski

Dimensioning Machine Structure for Earthquake Resistance in Design Stage

In the course of the design of powerplants and large chemical plants up to the middle of 20th century, the equipment has been designed and calculated taking into account standard and predictable loads ( temperature, pressure, rotational speed, wind) Through the design of large fossil and nuclear power plants and large chemical and petrochemical plants, mechanical and electrical engineers have encountered the need to evaluate the construction regarding possible earthquake. Designers started to perform earthquake calculations as well, significantly improving knowledge about earthquakes and response of different structures and machines [Singh 1992]. Demands on the safe operation of large plant equipment have became stricter during the last several years. The designers are faced with the demands of continuous operation or slight damages of the equipment during excess situations, which include earthquake. Gas turbines and steam turbines are mostly standardised products, which are installed in various locations in the world, and redesign to accommodate to local earthquake demands can be expensive and time consuming. However, earthquakes are partially random events, and there is no deterministic method, which fulfils all demands thoroughly. National and international bureaus of standards in different countries of the world try to overcome these problems [UBC 1977] , [EUROCODE 1994]. Because earthquakes are basically statistical events, buildings and plants are only statistically (probabilistically) safe to earthquakes. Risks of earthquake are classified for different constructions and purposes of construction, such as: apartments, workshops and office buildings ; public buildings, and infrastructure constructions. Most of the previously mentioned is the reason to design machines which would satisfy most location earthquake requirements in the world, but at the same time will not be too expensive to cover all locations. In this paper, an optimal seismic intensity for calculations is proposed, as well as the method of earthquake response calculation of the machinery structure.

earthquake; seismic acceleration; frequency response

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