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Seismic strengthening of buildings and seismic instrumentation — Two priorities for seismic risk reduction in Romania

Lungu, D. / Aldea, A. / Demetriu, S. / Craifaleanu, I.

Abstract According to the number of people lost in earthquakes during 20th century as well as in a single (March 4, 1977) earthquake during this century (1574 people, including 1424 in Bucharest), Romania can be ranked the 3rd country in Europe, after Italy and Turkey. Romania is followed by the former Yugoslavia and by the Greece (Bolt 1995, Coburn and Spence 1992). The World Bank loss estimation after the 1977 earthquake (Report No. P-2240-RO, 1978) indicates that from the total loss (2.05 Billion US $) more than 2/3 was in Bucharest, where 32 tall buildings collapsed. Half of the total loss was accumulated from buildings damage. The 1977 direct loss and indirect consequences of loss mark probably the starting point of economical decay of Romania during the next decade. They also explain the present concern of civil engineers and Romanian Government for assessment and reduction of seismic risk in Romania. The World Map of Natural Hazards prepared by the Münich Re (1998) indicates for Bucharest: “Large city with Mexico-city effect”. The map focuses the dangerous phenomenon of long (1.6 s) predominant period of soil vibration in Bucharest during strong Carpathians Vrancea earthquakes. The Bucharest and Lisbon are the only two European cities falling into Mexico-city category. International experts and organizations agreed that Bucharest is the capital city in Europe characterised by the highest seismic risk. The paper presents: Codes and standards for design of earthquake resistance of structures (1940–2000) and the draft of the new seismic Romanian code P100The structure of existing building stock in BucharestThe most vulnerable to earthquake categories of buildings, located on the soft soil condition of Bucharest tall reinforced concrete buildings in central Bucharest built prior to 1940 and severely damaged by the past 1977 eventtall reinforced concrete buildings with soft ground-floor built in Bucharest prior to 1977. Hospitals buildings, university buildings and other buildings, classified as having a high risk of severe damage/collapse in case of a strong earthquakeEnlargement of the existing seismic networks of Romania by two recent projects of INCERC and State Inspectorate for Construction and of NCERR and Japan International Cooperation Agency. In the last 6 months in Romania, the two projects provided about 50 (18 in Bucharest) digital Kinemetrics instruments (K2 and ETNA): in free field condition, in deep boreholes as well as in tall buildings.