Seismic Analysis: Past, Present And The Future
Free (open access)
D. Mestrovic, D. Cizmar & P. Roncevic
This paper summarizes earthquake calculations according to Eurocode regulations and codes applied in Croatia (Europe). The paper shows past, present and future methods for determination of seismic forces – an overview of all methods used is given. A simple pseudo static calculation is analyzed and compared to seismic forces according to Eurocode. An overview of spectral analysis according to Eurocode and Croatian code is given and discussed. Finally, time history analysis is discussed because as computer power increases with the availability of the strong motion database, the real records are becoming more popular for defining the input to dynamic analyses. The paper discuses three basic methods of input data – artificial records, synthetics accelograms and real records recorded during earthquakes. The possibility of using real records (for both linear and non-linear time history) is analyzed and discussed. A conclusion about the use of real accelograms (time history) versus spectral analysis is given. Keywords: seismic analysis, time history, accelogram. 1 Introduction An earthquake is a phenomenon that results from the sudden release of stored energy in the Earth's crust that creates seismic waves. At the Earth's surface, earthquakes manifest themselves by a shaking or displacement of the ground. Earthquakes are related to the tectonic nature of the Earth. The Earth's lithosphere is a composed of plates in very slow but constant motion caused by the heat in the Earth's mantle and core. Plate boundaries can grind past each other, creating frictional stress. When the frictional stress exceeds a critical value, a sudden failure occurs. The boundary of tectonic plates along which failure occurs is called the fault plane. When the failure at the fault plane results in a displacement of the Earth's crust, the elastic strain energy is released and
seismic analysis, time history, accelogram.