No abstract

An evaluation is presented of the response of a 3-storey R/C structure during the destructive Lefkada earthquake of 14/08/2003. Key aspects of the event include: (1) the unusually strong levels of ground motion (PGA = 0.48 g, SA max = 2.2 g) recorded approximately 10 km from fault, in downtown Lefkada; (2) the surprisingly low structural damage in the area; (3) the very soft soil conditions (V s,max = 150 m/s). Structural, geotechnical and seismological aspects of the earthquake are discussed. The study focuses on a 3-storey building, an elongated structure of rectangular plan supported on strip footings, that suffered severe column damage in the longitudinal direction, yet minor damage in the transverse one. Detailed spectral and time-history analyses highlight the interplay of soil, foundation and superstructure in modifying seismic demand in the two orthogonal directions of the building. It is shown that soil-structure interaction may affect inelastic seismic response and alter the dynamic behavior even for relatively flexible systems such as the structure at hand.

Two strong earthquakes hit Thessaly region on March 3rd, 2021 (Mw = 6.3) and on March 4th, 2021 (Mw = 6.1). The epicentres of the earthquakes were located at approximately 23 and 29 km respectively NW of Larissa, one of the most populous cities in Greece. Several aftershocks followed thereafter. Although no injuries were recorded, several structures suffered significant damage close to the epicentre, while some others collapsed. Approximately 300 residents of the village of Damasi were transferred to temporary settlements and tents. The event occurred during the COVID19 lockdown and created significant stress and disruption to residents. This paper focuses on the earthquake swarm itself as well as the damages observed in residential buildings, schools, and churches in the earthquake-stricken region. The earthquakes mainly impacted low-rise domestic masonry buildings, while the more modern reinforced concrete structures built following the recent seismic regulations were almost unaffected. The typology of buildings in the region, together with photographs demonstrating the extent of damage are presented herein. Despite the rather satisfactory performance of modern buildings in recent earthquakes in Greece, the preliminary investigations from the Thessaly Earthquakes showed that there is still a significant level of vulnerability in existing masonry building stock constructed using traditional methods and materials. This issue could re-emerge in future earthquakes striking other rural areas of Greece, something that needs to be addressed systematically in the future.

<p>A comparative study of codes from seismically active regions of various countries is presented covering US, European, Italian, Greek, Romanian, Brazilian and Bulgarian Standards. The study focuses on the comparison of certain critical points: recurrence periods; seismic zonation and design ground motion parameter values; shape of the response spectrum; soil amplification; importance levels; seismic force-resisting systems; behavior factors; structural irregularities; story drift limits; procedures for seismic analysis. Following the comparison of the text of the codes, their application on the seismic design of an ordinary reinforced concrete structure is presented. The structure is subjected to the seismic input according to the above set of codes and obtained results are compared highlighting the differences between the codes. Overall this study aims to assist to the future improvement of the various seismic standards.</p>

<p>The Task Group 1.1 of IABSE has proposed studies of comparisons among seismic codes, in order to find out discrepancies and similarities among them. The idea of the study is to select major international seismic design codes to be analyzed and compared among them. A comparative study of codes from seismically active regions of various countries is presented herein covering European, United States, Brazilian, Bulgarian, Canadian, French, Italian, Greek, Japanese, Mexican, New Zealander, Portuguese and Turkish codes and National Annexes of Eurocode 8. The study is focused in the criteria for the design of conventional (residential and commercial) buildings, analyzing some critical topics. A prototype reinforced concrete building is analyzed, considering all the codes under analyses and main results derived form the seismic design are compared.</p>