The project “RISKSOLVE – Evaluation and investigation of seismic risk reduction solutions for buildings, before and after earthquakes” – a starting point in the scientific cooperation of NIRD URBAN-INCERC, Romania, with IEM Harbin, P.R. of China (original) (raw)
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Engineering , State & Insurance Efforts for Reduction of Seismic Risk in Romania
2000
The paper describes procedures and actions adopted for assessment and reduction of seismic risk in Romania. The study is based on following information: (i) Design provisions for earthquake resistance of structures during 6 generations of seismic codes (1941 1998); (ii) Probabilistic hazard assessment in the influence area of subcrustal (60÷170 km) Vrancea source in Eastern Europe; (iii) Classification of model buildings of the Romanian building stock (iv) Vulnerability curves for typical RC and masonry model buildings and (vi) Expertise reports for the most damaged by earthquakes buildings in Bucharest. Using FEMA/HAZUS methodology (1997), the paper presents Guidelines for selection of the damage function for building structures in Romania, based on building age and seismic zonation map valid during construction of the building. Two Governmental countermeasures documents aiming at providing safety to strong earthquakes for the building stock of Romania are presented: Order No.6173/...
Seismic risk assessment of Faculty of Land Reclamation and Enviromental Engineering - Bucharest
Scientific Papers Series E Land Reclamation Earth Observation Surveying Environment Engineering, 2012
Increased vulnerability of human society to natural hazards is not so much due to a change in the way phenomena manifest, but also to anthropogenic causes, which require more than ever, a pertinent analysis of risk factors and constant involvement of specialists in all fields activity in reducing the negative effects they may cause to people, to the infrastructure or to environmental factors. Safety of structures is one of the main performance requirements for buildings. Expressed in a quality-like manner, this requirement must be completed with quantitative factors.
2002
A proposal for a new earthquake resistant design code (P100-2003) was developed in 2003 at Technical University of Civil Engineering Bucharest. It follows EUROCODE 8 [1] format. The present paper focuses on the representation of seismic action. A predictive contour map for peak ground acceleration PGA was prepared using GIS technology. The map also includes the contributions of all crustal sources affecting Romanian territory. The paper presents the zonation of the control period of response spectra Tc for the strong ground motions recorded in Romania, and the new proposed design spectra.
INTEGRATED SEISMIC RISK MANAGEMENT – THE DIFFERENCE BETWEEN THE CODES AND THE REAL LIFE PRACTICE
Earthquake Engineering emerged during the time from 1910 to 1930's, resulting with first building codes which included earthquake activities as loads. Seismic engineering need was triggered by devastating earthquakes in Northern California, and Messina -Italy. Since then, and especially during the last decades, earthquake engineering has increasingly advanced ever changing the norms and building codes. By now the preventive measures of earthquake risk mitigation have drastically evolved suggesting protection not only for new buildings, but also for the existing ones which make the majority of our surrounding built world.
EGUGA, 2014
Bucharest, capital of Romania (with 1678000 inhabitants in 2011), is one of the most exposed big cities in Europe to seismic damage. The major earthquakes affecting the city have their origin in the Vrancea region. The Vrancea intermediate-depth source generates, statistically, 2-3 shocks with moment magnitude >7.0 per century. Although the focal distance is greater than 170 km, the historical records (from the 1838, 1894, 1908, 1940 and 1977 events) reveal severe effects in the Bucharest area, e.g. intensities IX (MSK) for the case of 1940 event. During the 1977 earthquake, 1420 people were killed and 33 large buildings collapsed. The nowadays building stock is vulnerable both due to construction (material, age) and soil conditions (high amplification, generated within the weak consolidated Quaternary deposits, their thickness is varying 250-500m throughout the city). A number of 373 old buildings, out of 2563, evaluated by experts are more likely to experience severe damage/collapse in the next major earthquake. The total number of residential buildings, in 2011, was 113900. In order to guide the mitigation measures, different studies tried to estimate the seismic risk of Bucharest, in terms of buildings, population or economic damage probability. Unfortunately, most of them were based on incomplete sets of data, whether regarding the hazard or the building stock in detail. However, during the DACEA Project, the National Institute for Earth Physics, together with the Technical University of Civil Engineering Bucharest and NORSAR Institute managed to compile a database for buildings in southern Romania (according to the 1999 census), with 48 associated capacity and fragility curves. Until now, the developed real-time estimation system was not implemented for Bucharest. This paper presents more than an adaptation of this system to Bucharest; first, we analyze the previous seismic risk studies, from a SWOT perspective. This reveals that most of the studies don't use a very local-dependent hazard. Also, for major earthquakes, nonlinear effects need to be considered. This problem is treated accordingly, by using recent microzonation studies, together with real data recorded at 4 events with Mw≥6. Different ground motion prediction equations are also analyzed, and improvement of them is investigated. For the buildings and population damage assessment, two open-source software are used and compared: SELENA and ELER. The damage probability for buildings is obtained through capacity-spectrum based methods. The spectral content is used for spectral acceleration at 0.2, 0.3 and 1 seconds. As the level of analysis (6 sectors for all the city) has not the best resolution with respect to the Bucharest hazard scenarios defined, we propose a procedure on how to divide the data into smaller units, taking into consideration the construction code (4 periods) and material. This approach relies on free data available from real estate agencies web-sites. The study provides an insight view on the seismic risk analysis for Bucharest and an improvement of the realtime emergency system. Most important, the system is also evaluated through real data and relevant scenarios. State-of-the art GIS maps are also presented, both for seismic hazard and risk.
14 th World Conference on …, 2008
The paper investigates alternatives for design and/or strengthening of buildings, for structural and life safety, under extreme loadings, starting from earthquake engineering constraints. The Romanian Earthquake Code P100-1/2006 and EC 8 relate the life safety ultimate state and life safety criteria to collapse prevention through the mean recurrence interval of the design action. The recent EN 1991-1-7:2006 refers only to some accidental actions and internal explosions, but excludes external blasts, military actions and sabotage or tornadoes. The paper aims to cover this gap by a multi-hazard approach, with an integrated design of architectural and structural members. In Romania, many low-rise buildings are stiffer, made of masonry and concrete, while high-rise reinforced concrete structures are slender and are more vulnerable to Vrancea long-period seismic motions. The new urban landscape evolves to higher steel structures, with glass envelopes, atria, covered canopies, outside elevators, underground and overground spaces, where there is a danger of blast pressure and fire spreading on vertical and horizontal direction. Advanced earthquake resistant design is an asset but some members are sight exposed, have higher risk exposure and reduced redundancy to other extreme actions. We have studied plan and volume solutions vs. robustness and progressive collapse criteria and the use of safe rooms against risks caused by collapse or shattering and projection of debris. A strengthening solution was tested in INCERC on masonry specimens under diagonal compression, using CF plates, with good results.
2008
The paper investigates alternatives for design and/or strengthening of buildings, for structural and life safety, under extreme loadings, starting from earthquake engineering constraints. The Romanian Earthquake Code P100-1/2006 and EC 8 relate the life safety ultimate state and life safety criteria to collapse prevention through the mean recurrence interval of the design action. The recent EN 1991-1-7:2006 refers only to some accidental actions and internal explosions, but excludes external blasts, military actions and sabotage or tornadoes. The paper aims to cover this gap by a multi-hazard approach, with an integrated design of architectural and structural members. In Romania, many low-rise buildings are stiffer, made of masonry and concrete, while high-rise reinforced concrete structures are slender and are more vulnerable to Vrancea long-period seismic motions. The new urban landscape evolves to higher steel structures, with glass envelopes, atria, covered canopies, outside elevators, underground and overground spaces, where there is a danger of blast pressure and fire spreading on vertical and horizontal direction. Advanced earthquake resistant design is an asset but some members are sight exposed, have higher risk exposure and reduced redundancy to other extreme actions. We have studied plan and volume solutions vs. robustness and progressive collapse criteria and the use of safe rooms against risks caused by collapse or shattering and projection of debris. A strengthening solution was tested in INCERC on masonry specimens under diagonal compression, using CF plates, with good results.
Earthquake risk assessment for Romania
2000
Strong earthquakes in the Romanian Vrancea area have caused a high toll of casualties and extensive damage over the last centuries. The average recurrence rates make another strong event within the next 2 decades highly probable and provide a challenge to mitigate its impact. Romanian and German scientists from various fields (geology, seismology, civil engineering, operation research) organized themselves in the Collaborative Research Center (CRC) 461 'Strong Earthquakes: A Challenge for Geosciences and Civil Engineering' (Germany) and the Romanian Group for Strong Vrancea Earthquakes (RGVE) in a multidisciplinary attempt towards earthquake mitigation [17]. Key objectives of joint research activities are: • Understanding of the tectonic processes that are responsible for the strong intermediate depth seismicity beneath Vrancea. • Developing realistic models and predictions of ground motion. • Development of damage projections for the inner city of Bucharest based on seismological data, quantification of site effects and analysis of the built environment. • Detailed experimental study of the entire sequence relevant in earthquake engineering: source physics, wave propagation, site effects, soil-structure interaction, building performance. The Multidisciplinary Seismic Test Site located at INCERC, in the Eastern part of Bucharest serves as a focus to verify theoretical predictions by experimental data. Non-linear soil behaviour is a key issue in this context. • Development of novel approaches for mitigation of earthquake risk such as dynamic disaster management, new techniques for rescue and retrieval, retrofitting with fiber glass materials, rapid assessment of damage with photogrammetric methods and post-event shake maps.