Behaviour of masonry buildings during the earthquake of Bovec of July 12, 2004

摘要

On July 12, 2004, a magnitude M= 4,9 earthquake affected the area of the city of Bovec and vicinity. Although the earthquake was not strong by the magnitude, peak ground accelerations of a_(max) = 0,47g have been recorded in the epicentral zone and damage to structural walls has been observed in a number of buildings strengthened after the previous earthquake which occurred in the same area in 1998. Preliminary analysis of the record and ground soil amplification effects indicated that the intensity of the earthquake was equal or very close to the intensity of the design earthquake for the area of Bovec. Using advantage of the ground acceleration time history records, the response of typical strengthened masonry buildings has been analysed. The analysis has shown that the buildings vibrated in the non-linear range, although their seismic resistance was of the level of the one required by Eurocode 8. In most cases, the maximum calculated amplitudes of vibration have been far from the ultimate, so that the ductility and energy capacity of the buildings has not yet been fully utilized. As the observed damage state after the earthquake is in good correlation with calculations, the conclusion can be made that the design seismic loads, determined for masonry buildings according to the requirements of Eurocode 8, have realistic values.