Papers by Alexandru Aldea
Springer Proceedings in Earth and Environmental Sciences
The construction industry, as a main energy consumer and a foremost contributor to greenhouse gas... more The construction industry, as a main energy consumer and a foremost contributor to greenhouse gas emissions, has been undergoing a “green revolution” in the recent years. Sustainability has become a prominent issue, therefore a framework for including energy efficiency and sustainability in the design of buildings is badly needed. Sustainability is the core of the European Renovation Wave strategy and of the New European Bauhaus initiative.A design approach, named SAFESUST (SAFEty and SUSTainability) has been proposed at the Joint Research Centre of the European Commission, able to address at the same time structural safety, energy and environmental performances. The output of this approach is a unique parameter, expressed in monetary terms, which helps in identifying the most appropriate design solution.More recently, the Joint Research Centre, under mandate of the European Parliament, has activated a European Pilot Project named “Integrated techniques for the seismic strengthening...
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Frontiers in Earth Science, Apr 7, 2022
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Harmonization of Seismic Hazard in Vrancea Zone
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Constructii: Journal of Civil Engineering Research, 2020
Timber framed masonry houses represent a traditional type of house that can be found in many coun... more Timber framed masonry houses represent a traditional type of house that can be found in many countries in the world, having small differences in details though. In Romania, this type of house is spread around the Vrancea seismic source, but not limited to that area. Until now, no studies were done on the Romanian timber framed masonry houses in terms of ambient vibration testing and analysis. This paper presents the first study of this kind, conducted on a house with timber frames and masonry infills, which is located in the National Village Museum, namely representing Sarbova area, Timiş County. Ambient vibration tests were done using velocity sensors, and thus determining the modal frequencies, and a simplified analytical study was further conducted leading to similar results as the experiment.
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Digital seismic instrumentation donated by Japan International Cooperation Agency (JICA) to the N... more Digital seismic instrumentation donated by Japan International Cooperation Agency (JICA) to the National
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Seismic Hazard and Risk Assessment, 2018
The paper presents an overview of available data concerning ground types for seismic design in Ro... more The paper presents an overview of available data concerning ground types for seismic design in Romania. A short overview of a ground information database created during BIGSEES Romanian project is presented. A comparison of shear wave velocity for 19 sites in Bucharest determined by PS logging measurements and by Wald topographic slope method is discussed. The paper reiterates the conclusion of a study regarding the Eurocode soil factor S derived from the Romanian seismic motions. The need for an enlarged database of in situ determined ground condition is underlined, at least at the location of seismic stations. Based on borehole-specific data (geotechnical properties, hydrologic factors) and velocity profiles, evaluations of soil liquefaction potential and related indices were performed by using empirical equations proposed in literature. The application of GIS tools provided a spatial distribution of liquefaction susceptibility of Quaternary alluvial sediments in Bucharest.
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The southern part of Romania is characterized by special soil conditions, i.e. thick soil deposit... more The southern part of Romania is characterized by special soil conditions, i.e. thick soil deposits of Romanian Plain, leading to a long corner period of response spectra Tc=1.6s with associated large displacement demands in the Romanian Seismic Design Code P100-1 (2013). The stiffening approach to control the structural seismic response may therefore not be successful but the alternative solution of base isolation is promising. The first step towards this solution is to properly estimate the dynamic characteristics of buildings. The reinforced concrete frame structure of a hospital built in 2014 in the capital city Bucharest is investigated. It has an underground level and five stories and its shape is irregular. Its elastic dynamic characteristics under small amplitude vibrations are estimated using multi-sensor ambient vibration measurements combined with classical spectral analysis. The results are compared with numerical results obtained from the computation of a structural mode...
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The issue of correlation models of strong ground motions is widely discussed in the literature. N... more The issue of correlation models of strong ground motions is widely discussed in the literature. Numerous investigations of residuals obtained on various datasets of strong ground motions with different ground motion prediction equations offer spatial correlation models for either peak ground parameters or spectral response acceleration values. In this study, a dataset of 431 triaxial accelerograms recorded during ten earthquakes originating in the Vrancea intermediate-depth seismic source is used to obtain correlation models for peak ground accelerations and spectral response acceleration values. The interand intra-event residuals are obtained using a ground motion prediction equation for the geometric mean of two horizontal orthogonal components developed purposely for Vrancea intermediate-depth seismic source. The observed correlation coefficients for the geometric mean of the two orthogonal horizontal components and for the randomly orientated horizontal component at different vi...
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Seismic protection of cultural heritage constructions is a priority in earthquake prone countries... more Seismic protection of cultural heritage constructions is a priority in earthquake prone countries, due to their cultural, historical and touristic importance. The paper presents a first step toward the seismic evaluation of the “Carol I” Royal Mosque in Constanța, Romania: ambient vibration measurements and the assessment of the existing damage state induced by previous earthquakes and/or other actions (index R2 according to the Romanian code for seismic evaluation of existing buildings P100-3/2008). The mosque was built in 1910–1913 and has a masonry structure with a 26 m height reinforced concrete dome. It has an approximately 40 m height RC minaret and thus it is between the first civil constructions using reinforced concrete in Romania. The construction experienced the major earthquakes of 1940 (M W = 7.7) and 1977 (M W = 7.5) and several other medium size events originating from Vrancea subcrustal seismic source without significant damage. However, the long-term climatic aggres...
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This article presents a method to assess the sustainability of concrete based on three elements: ... more This article presents a method to assess the sustainability of concrete based on three elements: service life, performance and environmental impact. The method proposes - to achieve similar performance and service life times, regardless of the component materials used, so that the sustainability assessment ultimately depends on the environmental impact criterion. To this end, specific experimental methods are used to determine the performance of concrete in terms of compressive strength and carbonation resistance for concrete cast with two blended cement types. The procedure needed to classify the concrete through carbonation resistance is detailed, in relationship with the performance obtained for compressive strength. The obtained results highlight the concrete formulations to be used to ensure similar performances regardless of the cement type used. In conclusion, the simplicity in the application of the method, which is closely related to the performance approach on concrete dur...
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International Journal of Disaster Risk Reduction, 2021
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Czasopismo Techniczne, 2019
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E3S Web of Conferences, 2019
The population growth and/or its use and development of the land is a continuous preoccupation of... more The population growth and/or its use and development of the land is a continuous preoccupation of the decision factors regarding the water supply system in general and the development of the potable water distribution networks in particular. This issue is even more critical especially in the areas of big cities and important urban growing. As the urbanization of land outgrows the existing water supply systems, one of the possible solutions is to expand the water distribution network in order to cover this urban growth. The present paper analyses further the possibilities to define and use certain indices of urban development together with water loss indices in order to determine trends or issues related with the provision of water supply services and connectivity.
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Journal of Seismology, 2017
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Earthquakes and Structures, 2014
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Springer Natural Hazards, 2016
The seismic activity in Romania is dominated by the earthquakes generated at intermediate depths ... more The seismic activity in Romania is dominated by the earthquakes generated at intermediate depths (60÷180 km) in the Vrancea region, located at the bend of the South-Eastern Carpathians. The seismicity concentrates in a narrow high-velocity lithospheric volume embedded in the upper mantle. The rate of seismic moment per volume, ~ 0.8 x 1019 Nm/yr, is comparable to southern California (Wenzel et al., 1998). The event produced on 10th November 1940 (Mw = 7.7) was the largest instrumentally recorded earthquake in Romania, was felt in several other countries ( Bulgaria, Republic of Moldova, Ukraine, Russia, Greece, Turkey, Hungary, Yugoslavia, etc.) and produced victims and damage on a wide area beyond Romania’s borders. The large magnitude, the huge macroseismic field (with seismic intensities reaching X), the relatively large number of victims, altogether rank the Vrancea 1940 earthquake as one of the major European seismic events.
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Mathematical Modelling in Civil Engineering, 2015
The paper presents the modal characteristics of a tall building in Bucharest (BRD-SG Tower) ident... more The paper presents the modal characteristics of a tall building in Bucharest (BRD-SG Tower) identified from earthquake and ambient vibration records. The building was built in the early 2000’s and has a reinforced concrete structure (inner shear wall tube and perimeter frames) with 3 underground stories, ground floor and 18 stories. The seismic instrumentation of the building consists of a seismic station with two triaxial acceleration sensors located at the top of the building (+69.6 m) and at the third basement (−9.3 m). The dynamic characteristics of the building are estimated from the seismic records from 23 earthquakes (with moment magnitudes M
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International Conference „Earthquake Engineering in 21st Century”, Skopje & Ohrid, 2005 A... more International Conference „Earthquake Engineering in 21st Century”, Skopje & Ohrid, 2005 Authors: Dan Lungu, Sorin Demetriu, Iolanda-Gabriela Craifaleanu, Alexandru Aldea
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Strong Motion Instrumentation for Civil Engineering Structures, 2001
The accelerogram (0.2g peak ground acceleration and 1.6s long predominant period of soil vibratio... more The accelerogram (0.2g peak ground acceleration and 1.6s long predominant period of soil vibration) was recorded on a SMAC-B Japanese instrument and further digitized and processed by the Observational Committee ofStrong Motion Earthquake of the Building Research ...
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Papers by Alexandru Aldea