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domingo, 25 de enero de 2009

Seismic Risk, Class I

The Municipality of Bucharest is one of the capitals with the highest seismic risk in the world, suffering the impact of the earthquakes generated in the Vrancea seismic source, at 150 - 170 km epicentral distance. Historical information over one thousand years suggests a rate of 2-3 damaging earthquakes per century. In XX Century, there has been four major Vrancea earthquakes:

Date Moment Magnitude
10th Nov 1940 7,7 Mw
4th March 1977 7,4 Mw
31st August 1986 6,9 Mw
30th May 1990 7,1 Mw

The 1940 earthquake led to a first regulation of the Ministry of Public Works for earthquake resistant design (1943). On 4th March 1977, 21.20 local time, a 7,4-magnitude earthquake occurred, killing 1.570 people in Romania, and injuring around 11.000. The damages affected around 33.000 buildings and more than 700 factories, and were estimated by World Bank in two billion US dollars. Bucharest was severely affected: the earthquake caused the collapse of 32 buildings of 8-12 storeys, killing 1.424 people (90% of total casualties in Romania), while about 150 old buildings of 6 to 9-storeys were strongly damaged, many of them being subsequently demolished.

The earthquake affected specially to tall (more than 6-7 storeys plus 2-3 setbacks) reinforced concrete buildings built in Bucharest historical centre before 1940, on the soft soil of city centre characterized by a long predominant period of ground vibration (1.4-1.6s), and designed without earthquake requirements. However, cheap concrete shear wall constructions built after that date were also damaged, showing the inadequacy of 1940 regulation with regards to the actual earthquake threat in the area. Thus, anti-seismic construction requirements were raised; after 1989, the anti-seismic regulation was reviewed again, out ruling some unsafe kind of buildings still being built until that date.

The 1986 and 1990 earthquakes took place at noticeably different depths than the 1940 and 1977 earthquakes, and caused no remarkable damages in Bucharest; however, the risk of seismic catastrophe remains high, giving the collapse probabilities of the existing pre-1940/45 buildings. In Bucharest there's 180-200 blocks of flats of this kind, with more than 27.000 inhabitants. In fact, only the 40% of the population of Bucharest live in safe ductile buildings built after the 1977 earthquake: 1,2 million people are subject to different degrees of risk in case of earthquake.

Thus, anti-seismic policy, that has received constant support by international organizations and development agencies -World Bank funding and technical assistance from the Japanese JICA), is an important issue: amongst the prevention actions, the rehabilitation programme of Bucharest historical centre is one of the critical ones.

Clădire Clasa I risc seismic

All over Romania, buildings pass a technical audit in order to catalogue them according to their damage probabilities in case of earthquake, and there's both national and local programmes of inspection and rehabilitation (consolidation) of old buildings considered at risk.

Following technical audit, the buildings are divided in 4 types:
- Class 4. No major risk in case of earthquake.
- Class 3. Small damages in walls or decorations that can endanger the safety of the inhabitants.
- Class 2. No major risk of collapsing in case of earthquake, but risk of structural damages. This kind of buildings has been only partially catalogued.
- Class I. Major risk of collapsing in case of an earthquake with a magnitude higher than 7. In general, pre-1940 buildings, already affected by previous earthquakes. Of these, blocks of flats of more than 6 storeys (that is, highly populated) are considered a public danger, and its consolidation compulsory. Most (if not all) of these building has already passed technical audit in the 1990s.

All buildings class I are marked with a "red spot" indicating its state, and, despite what one might think, those "spotted" buildings are far of being empty or emptying: shops, restaurants, nice hotels and offices can be found in buildings showing the red signal.

Besides, the list of buildings that has passed the audit, and its classification, can be consulted at Bucharest City Hall and Regional Development and Housing Ministry websites. According to this list, 2639 buildings were inspected between 1993 and 2001, and 392 are catalogued as Seismic Risk Class I (126 of them, considered a public danger). According to Bucharest City Hall data (updated November 2008), only 16 buildings have been consolidated...

Bd. Regina Elisabeta nr. 47

I don't know if this is a exhaustive list; or rather, I doubt it is exhaustive, as I haven't found any reference to the 1910 building at Bd. Regina Elisabeta nr. 47, of great significance, as it is the Bucharest City Hall & Prefecture:

The red spot is not shown at the main façade, but in the right lateral, Strada Elie Radu, maybe to hide the shame. From my point of view, it's not a shame to be in a pretty building that happened to be built in 1910 and have some problems to be resolved, but to have been audited 10-15 years ago, with no consolidation works having been performed yet. It is difficult to trust an institution managing the local anti-seismic rehabilitation programme that has been, so far, incapable to rehabilitate its own headquarters.

I have found some references on the consolidation project of the Bucharest City Hall Building in the Internet, which gives us some tips on corruption problems, political problems and administrative problems delaying this and other equally important projects included in Romanian development plans:

- November 1999. The Ministry publishes the list of buildings at major risk in case of earthquake (Class I), which includes Bucharest City Hall. The Mayor, Viorel Lis, signs a contract (without tender) of 12 million EUR for a 5-year consolidation project.

- 2000. The new Major, Traian Băsescu (currently Romanian President), cancel the contract. No tender for procurement is published for the project.

(...)

- June 2007. The City Council (Mayor: Adriean Videanu) approves a consolidation project. The cost of the works is estimated in 15 million EUR, and the works would begin in 2007 and finish by 2010.

- 1 June 2008. Local and regional Elections. Sorin Oprescu is elected new Bucharest City Mayor. He stops many of the projects of the previous mayor; the City Hall consolidation, although suffer some delays, is assumed. (The future of other mayor projects regarding parking, road infrastructures, etc., remain unclear, as they have been redefined completely).

- January 2009. Tender for procurement closes (budget: 12 million EUR). The contract will be awarded in the following weeks, and the works should begin in March, lasting one year and a half, approximately.

miércoles, 21 de enero de 2009

Those quiet evenings / Esas tardes en calma

No lo negaré: a veces Bucarest puede conmigo. Tal vez por eso me gustan tante las tardes en las que vuelvo a casa paseando. Paseando, sí: porque hay movimiento pero las calles no están hechas un lío, el tráfico es fluido y no hay demasiados coches aparcados en las aceras, y puedo andar descuidadamente, un poco en las nubes, un poco en la tierra. Esas tardes en las que incluso disfruto con la iluminación afectada y fantasmagórica del monumento que hay en la Plaza de la Revolución, que me recuerda que uno no tiene que vivir en una ciudad con una belleza sin fisuras para sentirse bien. Intentaré no olvidarlo.

I won 't deny it: Bucharest sometimes gets on my nerves. That's why I like those evenings where I walk back home and, strangely, the city is busy but not messy, with fluid traffic and a reasonable amount of cars parked on the sidewalks, leaving some room to walk carelessly, even wander. Those evenings where I even look with fondness at the ghostly iluminated Monument at Revolution Square, which reminds me that you don't have to be in a undoubtedly pretty city to be at ease. I'll try not to forget.

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