The paper presents results from an experimental program implemented for three representative buildings in Bucharest metropolitan area and aimed to explore the potential of various dynamic identification methods in providing information about building state changes. The objective is to establish reference values of potential use in rapid earthquake damage detection systems. Each of the selected buildings was designed according to a different seismic code, in force at the time of its construction. The methods employed for this study were: the analysis of Fourier spectra, the analysis of the transfer function and the random decrement technique. To validate the results, the fundamental periods of vibration determined experimentally were compared with the corresponding values predicted by the empirical formulas specified in the corresponding editions of the Romanian seismic code. The results revealed consistent values for both the fundamental period and the damping ratio of the buildings. However, small variations of the two parameters were identified, depending on the time the recordings were performed, noise sources and levels and building occupancy. The results, in terms of validated data on the dynamic characteristics of Romanian building stock and of assessment of methods performance, add up to the information pool needed for the development of countrywide pre-and post-earthquake assisted decision tools.
The aim of this article is to analyze the background, current status, and outlook of seismic monitoring products and services in Bulgaria, Moldova, Romania, and Ukraine. These countries manage seismic networks that contribute to the European Integrated Data Archive node in the framework of the Observatories and Research Facilities for European Seismology, which represents a collaborative effort in coordinating observational seismology across the European region through the collection, archiving, and dissemination of seismic waveform data, metadata, and related products. All of the aforementioned countries share a common threat: strong earthquakes occurring in the Vrancea area located in central-eastern Romania at intermediate depths (usually in the 60–180 km interval). Events such as the ones on 10 November 1940 and 4 March 1977 generated high damage in Romania, northern Bulgaria, and Moldova. In addition to Vrancea, crustal earthquakes in areas such as Shabla or Dulovo can lead to cross-border damage. Therefore, understanding the way national seismic networks are distributed, how they cooperate, and the products and services that they provide in (near) real time and their terms is of significant interest in the context of necessary hazard harmonization and joint emergency intervention and risk mitigation actions.
Based on the background and expertise gained during almost two decades of development and implementation of virtual laboratory applications for teaching mechanics in engineering faculties, the authors propose a novel approach for this field, in which students themselves become developers of educational computer simulations. The method, called DYOVL ("Do Your Own Virtual Laboratory"), was applied, first experimentally and then on a regular basis, with gradual optimization during consecutive years, within the practical sessions of the mechanics course taught to students in automatic control and computers. An educational website, containing application examples and several downloadable resources, was recently developed, to assist teaching by the new method. The co-creative character of this process is manifold, as students work together with the teaching staff and with their team colleagues to program virtual laboratory applications or to suggest improvements for the existing ones. The method demonstrated favorable outcomes in terms of engagement, motivation, and inclusiveness, as well as a positive attitude of the students, shown both by pre-and during-COVID satisfaction surveys. To assist potentially interested academic staff in implementing this approach in their universities, detailed methodological guidance is provided.
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