CONSTRUCTII Journal

The paper presents some of the main scientific results achieved in the framework of a recently completed NATO Science for Peace and Security research project. The project aimed to harmonize the different seismic hazard maps of Romania, Moldova and Bulgaria and to develop standard maps in Eurocode 8 format, reflecting the real transboundary geophysical effects of the seismic phenomenon. In order to achieve these results, an important amount of research work in the field was carried out by the project teams of the three countries. The project also involved training of young scientists in the fields of seismic hazard, vulnerability and risk, organizing of seminars and workshops with international experts and upgrading the national seismic networks with new digital equipments. The general coordination of project activities and the evaluation of the project progress were performed by a scientific team from the Middle East Technical University (METU) in Ankara, Turkey.

The present paper is dedicated to Dr. Horea Sandi, a prominent scientist of Romanian structural and earthquake engineering, to honor his endeavours dedicated to the research school created in INCERC and in Romania, to his contribution in EAEE Working groups, to his life -time work on a conceptual and applicative framework in seismic risk and vulnerability analysis to fit specific patterns of Vrancea and Romania conditions. The 80-th anniversary of Dr. Horea Sandi is a perfect opportunity to review results from our recent research related to the consequences of the 1977 Vrancea earthquake, 35 years after its occurrence, as the authors benefited of first hand knowledge, warm guidance and cooperation from Dr. Sandi along decades. ABSTRACT Although its socio-economic disaster pattern was obvious, the March 4, 1977 Vrancea, Romania earthquake was studied mainly in seismological and earthquake engineering terms. In 1977, the loss data released in Romania, referred to 32,900 collapsed or heavily damaged dwellings, 35,000 homeless families, thousands of damaged buildings, many other damages and destructions in industry and economy, 1,578 people killed, 11,321 people injured (with 90% of the killed and 67% of the injured being in the city of Bucharest). The Romanian government reported the economic losses from this event in December 1977, as being US$ 2 billion. For a long time, the evaluation of human casualties vs. collapse pattern of buildings in 1977 was not addressed and we still miss integral data. The recovery and reevaluation of economic and social impacts of the 1977 disaster was a concern of the authors, with the intent to better understand its consequences and prepare a new strategy of seismic risk reduction in view of future earthquakes in Romania, and in order to fill that gap the authors recovered many unpublished and obscure data.

An industrially manufacturing recipe of foam glass gravel (FGG) from glass waste by an unconventional heating technique, using simultaneously a liquid foaming agent (glycerol) and a solid one (calcium carbonate) was tested on a 10 kW-microwave oven. Using a ceramic crucible based on silicon carbide with large dimensions, placed in a horizontal position, inside which a metal mold containing the finely ground pressed raw material mixture was inserted, the conditions were created to experiment the manufacture of a much higher quantity and on a significantly extended surface of 725 cm2 of foamed product compared to previous tests performed on a 0.8 kW-microwave oven. In terms of quality, the results were appropriate, the characteristics of FGG samples manufactured by sintering at 834-840 ºC using the conversion of microwave power to heat being within the limits of values required for this type of thermal insulation material (bulk density of 0.20-0.25 g/cm3, thermal conductivity of 0.062-0.070 W/m•K, compressive strength of 7.1-7.4 MPa, water absorption below 3% and pore size between 0.10-0.65 mm).

This paper is part of the series of pre-standardization research aimed to analyze the existing methods of calculating the Buildings Energy Performance (PEC) in view of their correction of completing. The entire research activity aims to experimentally validate the PEC Calculation Algorithm as well as the comparative application, on the support of several case studies focused on representative buildings of the stock of buildings in Romania, of the PEC calculation methodology for buildings equipped with occupied spaces heating systems. The targets of the report are the experimental testing of the calculation models so far known (NP 048-2000, Mc 001-2006, SR EN 13790:2009), on the support provided by the CE INCERC Bucharest experimental building, together with the complex calculation algorithms specific to the dynamic modeling, for the evaluation of the occupied spaces heat demand in the cold season, specific to the traditional buildings and to modern buildings equipped with solar radiation passive systems, of the ventilated solar space type. The schedule of the measurements performed in the 2008-2009 cold season is presented as well as the primary processing of the measured data and the experimental validation of the heat demand monthly calculation methods, on the support of CE INCERC Bucharest. The calculation error per heating season (153 days of measurements) between the measured heat demand and the calculated one was of 0.61%, an exceptional value confirming the phenomenological nature of the INCERC method, NP 048-2006. The mathematical model specific to the hourly thermal balance is recurrent – decisional with alternating paces. The experimental validation of the theoretical model is based on the measurements performed on the CE INCERC Bucharest building, within a time lag of 57 days (06.01-04.03.2009). The measurements performed on the CE INCERC Bucharest building confirm the accuracy of the hourly calculation model by comparison to the values provided by measurements and to those provided by the monthly calculation (NP 048-2006). The deviations of 1.45% and 2.2% respectively validate the hourly calculation model, as they actually have no physical significance. The report presents a phenomenological analysis of the building transfer functions synthesized as tev (τ), functions which attest their phenomenological objectivity in macro and hourly terms. The case studies completing the calculation models experimental validation emphasize unacceptably large differences between the results provided by the use of standardized calculation methods (Mc 001 / 2-2006 and SR EN 13790:2009) and those specific to the methods referred to in this report, experimentally validated.

The purpose of this paper is to present a procedure used in the assessment of the real heat transfer characteristic of shell and tube and plate heat exchangers. The theoretical fundamentals of the procedure are introduced as well as the measured data collection and processing. The theoretical analysis is focused on the adoption of criterial equations which, subjected to certain verification criteria presented in the paper, provide the most credible value of the convection heat transfer coefficients inside the circular and flat tubes. In the end two case studies are presented, one concerning a shell and tube heat exchanger operational at INCERC Thermal Substation and the other concerning a plate heat exchanger tested on the Laboratory Stand of the Department of Building Services and Efficient Use of Energy in Buildings of INCERC Bucharest.

The paper presents the environmental impact on steel structures and the corrosivity of atmospheric environments. It defines the principles and criteria for the evaluation of atmospheric-corrosivity classes, according to European standard, which were introduced in the new technical national regulations in the field of corrosion protection of steel structures. It shows the equivalence between the new corrosivity classes and the old aggressivity classes according to Romanian standard, still in force. The examples of typical environments corresponding to the corrosivity classes are also presented.

The dimensioning of the heating systems equipping new and existing buildings, in the case of their energy-related upgrading is an extremely important activity in the context of reaching the targets of the European Directive 31 /2010 / UE concerning the Buildings Energy Performance (PEC). The accurate determination, phenomenological based, of the buildings thermal response leads to determining the climatic parameters representative for the climatic zones and for the buildings structure.Unlike the EN 12831: 2003 European Regulation, the design outdoor temperature in the conditions of Romania’s various zones was determined by the identification of the thermal response specific to the transient conditions of the heat transfer through the composite structures of the opaque and glazing closing components with the thermal response in idealized, steadystate conditions; thus, the design outdoor temperature was determined, which is conditioned by an acceptable discomfort during the coldest pentads of a 48 years climatic statistics (1961-2008). The climatic parameter which generates the modeling similitude is the virtual outdoor temperature which allows the use of the steady-state conditions mathematical formalism in issues of heat transfer in transient conditions. A dependency relation between the design indoor temperature, identical to the resulting indoor temperature (different from the operational temperature) and the air volume average temperature is emphasized.Special attention is given to the heat transfer at the building-soil boundary, in the form of various practical solutions (buildings the basement of which is not directly heated, equipped or not with heating systems, directly heated and occupied, as well as buildings on plinths); in all the cases, the solutions approached are specific to the envelope which is or not thermally insulated.

The identification of the real thermal characteristic of an existing building implies mainly the assessment of the invariants specific to that structure, namely the equivalent thermal conductivity of the materials used for the opaque external envelope of the dwelling space. The paper focuses on the problem of identifying the thermal characteristic of the opaque external envelope of the apartment buildings with central heating system and implicitly with heating units in the dwelling and commune. The method used is of the inverse modelling type, based on the building global balance and on the thermal response of the heating system to random climatic conditions. The problem implies two phases as follows: - the preliminary phase, consisting in the integration of the heat balance differential equation of the dwelling spaces; - the final phase, based on the thermal response characteristic of the heating system in real operation conditions.

In the fall of 1963 I began my second year at the faculty of Civil, Industrial and Agricultural Engineering. After attending the first class of Strength of Materials with professor Mazilu, slightly intimidated by his fame, I was sitting in the seminar room anxious to meet his teaching assistant. Mr. Horea Sandi, a serious gentleman with a slightly timid air, entered the room and with a calm and smooth voice started explaining the slide rule. Little by little, we progressed through the curriculum and the seminars went on well. To the relief of many of my colleagues, I liked to volunteer and come up to the board; hence I acquired a solid knowledge base during the course of the semester. Professor Mazilu occasionally attended seminars and such visits kept everybody on their toes. Strangely, no visit was made to our group. At the time I did not know how to interpret this lack of visits to our seminars. I only later understood that Professor Mazilu saw no need to probe the quality of Mr. Sandi's seminars. During the exams period consultation sessions were held a few days before each examination. Mr. Sandi held our session and proved to be the first teacher that answered all questions to the point, without reiterating general concepts from their beginning. I was struck by how quickly and directly his answers shed light on issues I hadn't fully understood before. Later on I realized this is a privilege of those that fully understand concepts to their roots. In the end, when asked if the maximum grade at the exam was achievable he answered that I shouldn't be so materialistic. In my third university year, Mr. Sandi encouraged me to take part in the faculty's scientific session. I gladly took on the challenge and was keen on exploring beyond the level of the course. It was a good experience and it made me realize how little I knew and how many new problems one can imagine around aspects that seem clear at the first sight. The following year we benefitted from the same teaching crew for the Elasticity and Structural Dynamics courses. The atmosphere was much more relaxed at the course, as professor Mazilu had become pro-rector and he often amused us with adventures related to his new administrative position. However, the seminar classes remained unchanged. Despite knowing we would be allowed to openly consult our notes, we were not exactly at ease in the elasticity exam's eve. For the oral examinations, students drew three subjects from the pool and went away with their notes to prepare the answers. As usually, the examination stretched well into the evening. While professor Mazilu occasionally lost his patience and raised his voice, the teaching assistants kept a good humour which helped us deal with the stressful circumstances. Out of the three subjects I presented two to the professor and one to Mr. Sandi. Professor's Mazilu examination procedure seemed light in contrast with that of his teaching assistant. Mr Sandi waited for me to present the subject and when I finished my demonstration and thought everything was sorted out, he started a fairly long series of "what if" questions. And all this took place after 9 PM in a winter day. In the end it seems I coped well with the questions, but more importantly it served me as a great example of how to probe someone's intellectual abilities.

The proposal presented subsequently was forwarded by the author, in August 2010, on the eve of the 14 th European Conference on Earthquake Engineering, to: -Prof. Atilla Ansal, Secretary General, EAEE; -Dr. Mariano García-Fernández, Secretary General, ESC. This proposal was to a high extent a follow up of the project "Quantification of seismic action on structures" (2005-2008), in which research groups of institutes of Romania (coordination), Russian Federation and Republic Moldova were involved. A summary outcome of the project referred to is represented by the volume [Sandi & al., 2010a]. A brief presentation of the volume referred to is given in its foreword, reproduced in Annex II. The correspondence related to the submission of the proposal is reproduced in Annex III. A paper on this subject, [Sandi & al., 2010b], presented at the 14 th European Conference on Earthquake Engineering, is also reproduced in this issue of the journal.

The object of the paper is represented by an attempt to contribute to an adaptation of the concept of seismic intensity to the needs of engineering activities. A first condition in this connection is to pay the attention due to the spectral contents of ground motion. A case where rough approaches have led to erroneous estimates of ground motion severity, resulting in erroneous hazard estimates is presented. The main conclusion derived is represented by the strong need to specify the spectral interval for which macroseismic data are relevant and, as a consequence, to consider (and even to define) seismic intensity derived from post-earthquake surveys as related to a certain spectral interval. A methodology proposed in order to define and determine seismic intensity on the basis of instrumental data and, moreover, to define and determine seismic intensity spectra is then presented. Some illustrative examples are given.

Record levels of air pollution, leading to environmental degradation, deteriorating health and climate change, are affecting cities around the world. However, due to the confinement measures imposed at the beginning of the COVID-19 pandemic, reductions in nitrogen dioxide (NO2) concentrations - one of the main traffic pollutants - have been reported in many cities in Europe and around the world: by over 50% in Barcelona as of March 21, 2020, 64% in other cities in Spain, about 40% in London or about 50% of carbon monoxide (CO) levels in New York. In this context, the paper presents the results of monitoring NO2 concentrations within the INCERC Bucharest Branch, located in the eastern part of Bucharest, the capital of Romania. Keywords: outdoor air; COVID-19 pandemic; nitrogen dioxide; health

The frequency-dependent spectrum based seismic intensity, also called instrumental intensity, is calculated basically from the integration of the square values of spectral acceleration ordinates. The values of the instrumental intensity are calibrated to match the values of the EMS-98 intensity scale, providing a promising analytical indicator for estimating the destructive potential of earthquakes. Previous studies have shown that the proposed index could be used as a basis for the development of a new improved seismic intensity scale. The paper presents a set of maps describing the spatial distribution of the instrumental intensity ordinates for three seismic events recorded in 1986 and 1990. These events, generated by the Vrancea source, are the strongest earthquakes that occurred in Romania and for which accelerographic data was recorded at multiple stations. Intensity maps were generated for separate significant frequency bands, in order to reveal the destructiveness of the considered earthquakes for different building categories. Results were compared and correlated with previous research on Vrancea earthquakes and with information provided by building damage reports from the considered earthquakes.

The construction field represents an important part of the Romanian economy (and of UE), with a strong social impact on the quality of citizen life. Naturally, the research from the construction field should be a priority in research and innovation activity. However, the research programs recently launched (Horizon 2020, from EU, and the Strategy of Research and Innovation 2014-2020 in Romania), don’t mention the construction field as an explicit priority. Under these conditions, we can speak of a real identity crisis of the research in construction, a crisis which may worsen in the next seven years, as an effect of limiting the access to material and human resources, caused by the field marginalization. In this paper, a detailed analysis of the mentioned research programs is done, in order to identify possible connections with research in construction and some research directions, additional to the priority directions. Some probable causes that led to the crisis in construction research are identifies, as well as possible measures, actions, directions and research topics that can rally researchers in the field. From the conclusions drawn in the final section, it results that the identity, place and role of research in construction can be found in the interaction and close collaboration with research from other areas, in inter-, multi-, or trans-disciplinary teams.

A recently proposed method for scaling real accelerograms to obtain sets of code-compliant records is assessed. The method, which uses combined time and amplitude scaling, corroborated with an imposed value of an instrumental, Arias type intensity, allows the generation of sets of accelerograms for which the values of the mean response spectrum for a given period range are not less than 90% of the elastic response spectrum specified by the code. The method, which is compliant with both for the Romanian seismic code, P100-1/2006, and Eurocode 8, was described in previous papers. Based on dynamic analyses of single-degree-of freedom (SDOF) and of multi degree-of-freedom (MDOF) systems, a detailed application and assessment of the method is performed, for the case of the long corner period design spectrum in Bucharest. Conclusions are drawn on the advantages of the method, as well as on its potential improvement in the future.

Ultra-High Performance Concrete (UHPC) is a relatively new concrete. According to [11] UHPC is that concrete which features compressive strength over C100/115 class. Up to this point standards for this type of concrete were not adopted, although its characteristic strength exceeds those specified in [33]. Its main property is high compressive strength. This provides the possibility of reducing the section of elements (beams or columns) made of this type of concrete, while the load capacity remains high. The study consists in blending mixtures of UHPC made of varying proportions of materials. The authors have obtained strengths of up to 160 MPa. The materials used are: Portland cement, silica fume, quartz powder, steel fibers, superplasticiser, sand and crushed aggregate for concrete - andesite.

External environment can act on colored coating products used as construction finishing materials through climatic factors (UV radiation, moisture, temperature) causing photochemical degradation reactions at the structural level, with direct implications on the aesthetic character through loss of the colorimetric properties but also on the protective role by reducing physical and mechanical properties. From this perspective, accelerated test exposure to UV radiation under conditions that simulate the action of climatic factors from natural environment are of particular importance and evaluating methods for colored coating products degradation at the end of exposure offers the possibility to obtain the data about their behavior in service. The article presents methods of visual evaluation on colored coating products degradation, which are based exclusively on qualitative evaluations influenced by the examiner, compared to the instrumental methods that allow to reduce the uncertainty induced by the human factor and to obtain accurate and quantifiable results to contribute in establishing the sustainability and the performances of the finishing coating materials.

Polluting emissions from building materials are among the construction " problems " , but when they occur along with other factors (particle allergens, cigarette smoke, gas exhaust, electromagnetic fields, etc.) together can lead to so-called syndrome " sick-building ". Why should we so intensely interested in the hazards present in our houses? The answer is: because the highest dose of exposure to toxic substances is right here in our houses or in the spaces in which we work. REZUMAT Emisiile poluante ale materialelor de construcţii se numără printre " problemele " construcţiilor, îns atunci când acestea se produc concomitent cu alţi factori (particule alergene, fum de ţigară, gaze de eşapament, câmpuri electromagnetice etc.), împreun pot conduce la aparicia aşa-numitului sindrom " sick-building " (cas bolnav). De ce ar trebui să ne intereseze atât de mult noxele prezente în casă? Răspunsul este: pentru că cea mai mare doză de expunere la substanţe toxice se află chiar în casa în care locuim sau în spaţiile în care lucărm.

The Alto Douro Wine Region, located in the northeast of Portugal, a UNESCO World Heritage Site, presents a relevant tabique building stock, a traditional vernacular building technology. A technology based on a timber framed structure filled with a composite earth-based material. Meanwhile, previous research works have revealed that, principally in rural areas, this Portuguese heritage is highly deteriorated and damaged because of the rareness of conservation and strengthening works, which is partly related to the non-engineered character of this technology and to the growing phenomenon of rural to urban migration. Those aspects associated with the lack of scientific studies related to this technology motivated the writing of this paper, whose main purpose is the physical and chemical characterization of the earth-based material applied in the tabique buildings of that region. Consequently, an experimental work was conducted and the results obtained allowed, among others, the proposal of a particle size distribution envelope in respect to this material. This information will provide the means to assess the suitability of a given earth-based material in regard to this technology. The knowledge from this study could be very useful for the development of future normative documents and as a reference for architects and engineers that work with earth to guide and regulate future conservation, rehabilitation or construction processes helping to preserve this fabulous legacy. REZUMAT Regiunea viticolă Alto Douro, localizată in nord-estul Portugaliei, o regiune aflată în Patrimoniul UNESCO, prezintă o multitudine de clădiri construite prin metoda tabique, o tehnologie tradiţională, vernaculară, de construcţie. Această tehnologie se bazează pe o structură în cadre de lemn umplute cu un compozit având pământul ca material de bază. Între timp, cercetările anterioare au arătat faptul că, în principal în zonele rurale, această moştenire portugheză se pierde în timp datorită rarităţii lucrărilor de conservare şi consolidare, caracterului neingineresc al acestei tehnologii şi creşterii fenomenului de migraţie rurală către zonele urbane. Aceste aspecte, asociate cu lipsa studiilor ştiinţifice legate de această tehnologie, au motivat scrierea articolului de faţă, al cărui scop principal este caracterizarea fizică şi chimică a materialului pe bază de pământ folosit in construcţiile realizate din tabique în regiunea respectivă. Astfel, a fost realizat un studiu experimental, iar rezultatele obţinute au permis, între altele, propunerea unei înfăşurători (a unei curbe granulometrice) a distribuţiei mărimii particulelor din componenţa materialului menţionat. Această informaţie va oferi mijloacele pentru a evalua adecvarea unui material de bază de pământ, utilizat în cadrul tehnologiei respective. Cunoştinţele dobândite în urma studiului pot fi foarte utile pentru dezvoltarea de documente normative viitoare, precum şi ca referintă pentru arhitecţii şi inginerii interesaţi, pentru îndrumarea şi reglementarea viitoarelor lucrări de conservare, reabilitare şi construcţie, sprijinind ocrotirea acestei minunate moşteniri. Cuvinte cheie: Regiunea viticolă Alto Douro; tabique; tehnici tradiţionale de construcţii; teste de caracterizare; compozite pe bază de pământ.

This paper presents an analysis of a study carried out within the CA2 European project, the topic of which is the estimation of the rate of the activities carried out in view of the issuing of the new and existing dwelling and public buildings energy performance certificate. It results that the simplification of the methods of calculation of the Buildings Energy Performance is a real target of the activity devoted to the buildings certification activity, especially supported in the case of the individual and collective dwelling buildings. The statistical analysis of the existing building stock and of the trend in building performance in the last 5 years in Romania leads to the conclusion that it is necessary to equally approach the certification of the collective and of the individual buildings. The simplifications proposed in this paper are based on the processing of the data provided by the thermal bridges catalogues as well as on the use of the data provided by the processing of the calculation model corresponding to the conventional block of flats, used in the case of some representative localities in the climatic zones of the country.

The energy footprint of a building is an operational characteristic specific to the building structure as well as to the energy-related operational conditions of the building. This paper presents the experimental program carried out on the support of the experimental house INCERC Bucharest experimental building in the 2008-2009 cold season and the results obtained in the form of the building energy footprint. At the same time, the building energy footprint before the energy-related upgrading (2003-2004 cold season) are presented, as well as those subsequent to the energy-related upgrading (thermal protection, equipping with a ventilated solar space and heating system replacement). The character natural laws of the energy footprint is emphasized. This paper presents a theoretical substantiation of the use of the energy footprint method in the case of condominiums in the form of the operational method, which is useful in settling the functional characteristic in any climatic conditions and in any operational conditions.

The paper presents the main antiseismic devices, as component elements of the base isolation systems, in such a manner that the functional and constructive parameters are correlated with the inertial and stiffness characteristics of the dynamic isolated building. Also, each device will be characterized through a rheological model, which conditions the eigenvalues and eigenvectors spectrum, as well as the dynamic response to an exterior excitation of a seismic nature. In this context, antiseismic devices defined and characterized by the European Standard EN 15129 will be presented. Based on the requirements formulated in the norm, the devices can be identified and their laws of evolution established and checked as follows: antiseismic devices with permanent rigid connection; antiseismic devices with rigid connections with respect to the instantaneous displacement and antiseismic devices dependent on the velocity and on the velocity variation in time.

The paper presents the seismic performance assessment of a reinforced concrete frame structure representative for existing buildings in Bucharest. The assessment was performed using deterministic and probabilistic approaches, the last using Response Surface Methodology. Finally, fragility curves were obtained considering the peak ground acceleration as seismic intensity measure.

The Response Surface Methodology is a useful way for assessing the seismic performance of structures. A description of this methodology and a short introduction into the Design of Experiments are presented. By using the cumulative probability density obtained after 10,000 Monte Carlo simulations on the response surface functions, it is illustrated, by a case study, the way in which the probability of a system of being in a damage state can be estimated.

The educational habitat is one of the critical social infrastructures in a society, the first place for social activity and the most important indoor environment for children, besides their home. The increasing interest in indoor environmental quality of the educational habitat has been emphasized by the rising incidence of respiratory infections and allergic diseases among children, who spend a substantial part of their lives on the school premises. Scientific knowledge on the monitoring of indoor pollutants for their quantitative and qualitative identification, on the sources identification of them, and associated health risks among children are essential to the evaluation and assurance of the educational habitat health, through the adequacy and cost effectiveness of the measures for mitigating the indoor environment issues. REZUMAT Habitatul educațional este una dintre infrastructurile sociale critice într-o societate, primul loc pentru activitatea socială și cel mai important mediu interior pentru copii, pe lângă locuință. Interesul crescând manifestat pentru calitatea mediului interior specific habitatului educațional a fost susținut de creșterea incidenței infecțiilor respiratorii și a bolilor alergice la copii, care își petrec o parte substanțială din viața lor în spațiile școlare. Cunoștințele științifice privind monitorizarea poluanților din mediul interior pentru identificarea lor cantitativă și calitativă, identificarea surselor și a riscurilor asociate pentru sănătate în rândul copiilor sunt esențiale pentru evaluarea și asigurarea sănătății habitatelor educaționale, prin adecvarea și rentabilitatea măsurilor pentru atenuarea problemelor privind calitatea aerului interior.

One of the main causes of casualties in major earthquakes around the world is the collapse of low earthquake resistant masonry structures. Retrofitting of these types of structures is the key issue for earthquake disaster mitigation in developing countries because it is the only way to significantly reduce casualties in future earthquakes. This paper presents an innovative retrofitting method for masonry houses, which consists of polypropylene bands (PP-band) arranged in a mesh fashion. The PP-band technology aims to prevent or, at least, put off wall collapse by providing both sides with the mesh made of a cheap packthread and keeping the integrity of the walls. In order to verify the suitability of the proposed method, a series of masonry wallettes, with and without retrofitting, was tested under in-plane and out-of-plane loads. Although the retrofitted wall peak strength was almost the same as that of the bare wall, its post-peak strength was larger and sustained for lateral drifts. In order to investigate the proposed retrofitting features for different material properties and mesh configurations, tests on number of masonry wallettes were performed.

Self-compacting concrete (SCC) is a new generation of high-performance concrete, known for its excellent deformability and high resistance to segregation and bleeding. Nonetheless, SCC may be incapable of resisting shear because the shear resistance mechanisms of this concrete are uncertain, especially the aggregate interlock mechanism. This uncertainty is attributed to the fact that SCC contains a smaller amount of coarse aggregates than normal concrete (NC) does. This study focuses on the shear strength of self-compacting reinforced concrete (RC) beams with and without shear reinforcement. A total of 16 RC beam specimens was manufactured and tested in terms of shear span-to-depth ratio and flexural and shear reinforcement ratio. The test results were compared with those of the shear design equations developed by ACI, BS, CAN and NZ codes. Results show that an increase in web reinforcement enhanced cracking strength and ultimate load. Shear-tension failure was the control failure in all tested beams.

The paper presents conclusions from a technical benchmarking study, performed in order to analyze the performance of the provisions concerning seismic design of reinforced concrete frame structures, as specified by the Romanian seismic code (P 100-1 / 2006). The Romanian code is analyzed with respect to the European standard EN 1998-1 : 2004, including its National Annex, and with the U. S. codes IBC2009 and ACI 318 08. The benchmarking analyses were performed by designing a standard reinforced concrete structure according to each of the considered codes and by evaluating the seismic behavior of the structural designs thus obtained. Comparative assessments are made, as well as suggestions concerning potential future research directions, aimed to the improvement of the Romanian provisions in the field.

The paper presents a study on modelling the wind drifting of the snow deposited on the flat roofs of buildings in wind tunnel. The physical model of snow drifting in wind tunnel simulating the urban exposure to wind action is not frequently reported in literature, but is justified by the serious damages under accidental important snow falls combined with strong wind actions on the roofs of various buildings. A uniform layer of snow deposited on the flat roof was exposed to wind action in order to obtain the drifting. The parameters involved in the modelling at reduced scale, with particles of glass beads, of the phenomenon of transportation of the snow from the roof were analysed, particularly the roughness length and the friction wind speed. A numerical simulation in ANSYS CFX program was developed in parallel, by which a more accurate visualization of the particularities of the wind flow over the roof was possible, in the specific areas where the phenomenon of snow transportation was more susceptible to occur. Modified roughness length and friction wind speed were determined through methods used in the literature, an attempt being made in this work to analyse the factors that influence their values.

Infrastructure is an indispensable and decisive requirement for the economic development of a country; it is directly linked to the set of structural economic activities and serves as the foundation for the development of other activities. In this context, the bridges have fundamental importance to the social and economical development of the cities, because the roads are to ensure the entry of inputs on farms, as well as the disposal of products and free movement of populations. The aim of this study is to present a survey of the existing bridges in the south region of Brazil, more specifically in the city of Pato Branco, identifying the most recurrent damages, in order to provide bases to administrators, with the intention of ensuring the correct functioning of the transport infrastructure and in the preservation of public property and security for the users. Data collection was conducted through visits, using the method of visual and photographic records. After the analysis was done, we identified several pathological manifestations, both in concrete and wood bridges, such as moisture stains, cracks, corrosion, erosion, clogging of drains; wood decay, lack of verticality of the pillars and foundation repression, among others. Moreover, there was little or no maintenance on the existing bridges. Similar conditions can be observed in most cities in the south region of the country.

As it is well known, Romania and its capital, Bucharest, suffered building collapses, heavy damage and casualties in the 1940 and 1977 Vrancea earthquakes. The paper presents methods for the assessment of urban multi-hazard risks for emergency planning, using affordable tools. The scenarios for night and day time impact in the pilot study protected area have shown that: - Earthquake damage and casualties can be significant; for the seismic intensity I = VIII, a number of 63 buildings would suffer considerable damage, while for I = VIII½, the damage would affect 165 buildings, mostly low-rise structures. The number of heavy injured persons would be 29 and 64, while live loss will be 59 and 92, respectively, for the considered intensities. The damage would affect safety of living for about 1,809 to 3,061 people. - The scenario of climatic and hydrologic hazards is dominated by an extreme event of accidental flooding, in which the water cover could be as high as 2.5 m; - The terrorist blasting scenario has shown that, as the explosive quantity increases, the impacts would have great potential of damage, injured people and casualties.

The world is changing, and it is changing fast within a liquid society. However, the benefits of this change have not equally spread throughout the world. To tackle these issues, in 2015 the United Nations (UN) outlined 17 Sustainable Development Goals to be reached by 2030. The 11th goal is focused on the sustainable development of cities. Contemporary cities are the main stages for social, cultural and technological changes. Within the discourse on contemporary cities, Landry identifies the Civic City as an entity which "tries to find a pathway through the major faultiness, dilemmas and potentials of our time". In this context, Civic Design attempts at answering its wicked problems, aiming at fostering community resilience through design-driven interventions. The article first explores the state of the art of the notion of Civic Design, then focuses on how Civic Design experiences enable resilient communities, by linking Civic Design capabilities to the notion of "evolutionary resilience". Full article here: http://www.sustainablemediterraneanconstruction.eu/SMC/The_Magazine_n.12_files/1226.pdf

Romania currently undergoes a development of the software used in assessing Buildings Energy Performance. In order to grant the free movement of the products and services in the European space, the Buildings Energy Performance software cannot be subjected to a certain design algorithm based on a regularized mathematical model. Therefore it is necessary to develop a pattern which should provide the possibility of testing the commercial software using different design and structuring algorithms. A maximum level of the necessary input data is settled as well as a minimum level of the data resulted from calculations. The assessment of the software is based on a synthetic report including the input data and the values provided by calculations, for a variable number of testing sheets. The software used in assessing the similar commercial products must be based on experimentally validated calculation methods. The dynamic calculation mathematical models included in the structure of the Validation software do not mark the difference between the seasons (hot-cold) and may be adapted to any initial conditions operating as input data. According to the validation procedure, the mathematical models substantiating the calculation methods specific to the Standard Validation / Attesting Software (PCVE) are experimentally validated by long-term measurements performed on full-scale models, in a controlled microclimate. The development of the patterns of validating the calculation methods and the software offers a new approach of the Buildings Energy Performance Calculation Methodology focusing the regulated contents on the EPB quantification methodological principles, phenomenologically substantiated as well as on providing the calculation support by software attested by the procedure of inter-validation in terms of the Standard Validation Software, experimentally validated. The new approach may represent a determining step forward in harmonizing the EPB calculation methodologies and in providing a highly accurate computer based management of the EPBD implementation national strategies. This article presents the phases in preparing and finalizing the national pattern of validating the software to be used in drafting CPEA according to the Romanian legislation.

Currently, a large number of seismic records, obtained over the years on instrumented buildings with various heights, located in urban environment, are available at global scale. The valorization of these records is important, as frequently no other information exists for the corresponding or neighboring locations. Several studies carried out recently have shown that the influence of the building can be separated, if certain characteristics of the structure-foundation-soil system are known. The paper presents the first results of an investigation concerning the usability of seismic records obtained in the past on stations located on buildings from densely urbanized areas in Romania. The reconsideration of the information provided by these stations could provide new perspectives on the spatial distribution of the ground motion parameters for the past earthquakes and, implicitly, a better understanding of the characteristics of seismic hazard in Romania.

A brief account on the characteristics of the seismic region and events in Chile reveals interesting indices in understanding the present day Chilean seismic design code. The present article points out some of the most important provision in the Chilean code that could have led to the relatively small number of casualties at the seismic event of February 27th 2010. By comparing the Chilean code to the Romanian one, the goal is to underline the differences and the similarities regarding both the conceptual and formal aspects. Observations are pointed out by means of comparative graphs of significant parameters. Based on statistics of recorded damage published after the earthquake, some comments are made about the importance of the quality of seismic codes and of the effectiveness of their enforcement.

The paper presents experimental results of the research carried out in order to obtain an innovative finishing/protection product for plasterboard surfaces, using sunflower seed husks, waste generated by the edible oils industry. In the form of an addition consisting of one or two-dimensional fractions, sunflower seed hulls have been incorporated into a finishing/protective coating product, the latter acting as a binder. The multilayered application of the resulting products, on gypsum board surfaces, led to a coating having good adhesion to the support as well as good thermal insulation characteristics (between 0.165 W/m.K and 0.095W/m.K), despite the small thicknesses of the coating (between 3.15 mm and 5.10 mm) compared to the traditional products with thermal insulating properties. REZUMAT Lucrarea prezintă rezultate experimentale ale cercetărilor efectuate în vederea obținerii unui produs inovator de finisare/protecție a suprafețelor de gips carton, prin utilizarea de coji de semințe de floarea-soarelui, deșeu generat de industria uleiurilor comestibile. Sub forma unui adaos alcătuit din una sau două fracțiuni dimensionale, cojile de semințe de floarea-soarelui au fost înglobate într-un produs peliculogen de finisare / protecție, ultimul având rol de liant. Aplicarea în sistem multistrat a produselor rezultate, pe suprafețe de gips-carton, a condus la obținerea unor acoperiri cu o bună aderență la suport precum și cu bune caracteristici de izolare termică (între 0,165 W/m.K și 0,095W/m.K), în ciuda grosimilor mici ale acoperirii (între 3,15 mm și 5,10 mm) comparativ cu produsele tradiționale cu proprietăți termoizolatoare. Cuvinte cheie: deșeu vegetal; finisaj; izolare termică; sistem multistrat.

In this study the risk for progressive collapse of RC framed buildings located in seismic areas in Romania is investigated. Structures with three, six and ten stories, each in turn are designed for three distinct seismic zones: low (ag=0.08g), moderate (ag=0.16g) and high (ag=0.24g). Using the provisions provided by the GSA (2003) Guidelines, a nonlinear dynamic analysis is carried out first in order to establish the risk for progressive collapse of the models under investigation. It is shown that all the structures are not expected to fail when subjected to abnormal loading (sudden column removal). A nonlinear incremental dynamic analysis is conducted next in order to estimate with the maximum accuracy the ultimate load bearing capacity to progressive collapse of the damaged models. Based on the capacity curves provided by this procedure, it is shown that all the structures are capable of sustaining a higher load than the standard GSA loading before failure. Using these capacity curves, the influence of the seismic design on the progressive collapse resistance is quantified as well.

Determining the concrete compressive strength is an important issue for both existing and new constructions. Existing constructions, subject to retrofit and / or extension, require the determination of concrete compressive strength in specific elements, for the realistic and correct evaluation of the structure in terms of overall strength and stability. New constructions, on the other hand, may face situations when there are doubts about the quality of the delivered concrete, the casting operations or other technological or design flaws. The correct determination of the actual concrete compressive strength may be essential in evaluating the structural health and identifying the optimum design and technological solutions for the evaluated building. Non-destructive methods for determining the concrete strength are, by definition, minimally invasive methods, namely they do not affect the integrity of the structure. This paper provides a comparison between the combined non-destructive method and the destructive, classical method for compressive strength determination. REZUMAT Determinarea rezistenţei la compresiune a betonului reprezintă un deziderat important atât pentru construcţiile existente, cât şi pentru construcţiile noi. Construcţiile existente, supuse unor consolidări şi / sau extinderi, necesită determinarea rezistenţei la compresiune a anumitor elemente, pentru a putea efectua o evaluare realistă şi corectă a structurii din punct de vedere al rezistenţei şi stabilităţii. Construcţiile noi, pe de altă parte, se pot confrunta cu situaţiile când există dubii cu privire la calitatea betonului livrat, cu modul de punere în operă sau cu alte abateri tehnologice sau de proiectare. Determinarea corectă a rezistenţei efective la compresiune a betonului poate fi esenţială în evaluarea sănătăţii structurale şi în identificarea şi alegerea soluţiilor optime, de proiectare şi tehnologice, pentru clădirea evaluată. Metodele nedistructive de determinare a rezistenţei betonului sunt, prin definiţie, metode minim invazive, în sensul că nu afectează integritatea structurii. Articolul oferă o comparaţie între metoda nedistructivă combinată şi metoda standard, clasică, de determinare a rezistenţei la compresiune.

Indoor environment affects equally the health, the productivity and the occupants comfort, the costs for employers, owners of the buildings and the society being significantly larger, in the case of an inadequate interior ambient. Therefore, a good indoor air, in the office spaces, leads to the improvement of the work performance and to the decreasing of the absenteeism. Moreover, the occupants of discomfortable spaces will have the tendency to react in order to reduce their own discomfort, with consequences on the energy consumption. REZUMAT Mediul interior afectează în mod egal sănătatea, productivitatea şi confortul ocupanţilor, costurile pentru angajatori, proprietari ai clădirilor şi societate, fiind considerabil mai mari, în cazul unei ambianţe interioare necorespunzătoare. Prin urmare, un aer interior de bună calitate, în spaţiile de birouri, conduce la îmbunătăţirea performanţelor de muncă şi la reducerea absenteismului. În plus, ocupanţii unor spaţii inconfortabile vor avea tendinţa de a recţiona în vederea reducerii disconfortului propriu, cu consecinţe asupra consumului de energie.

The paper is mainly focused on the investigation of the seismic response of reinforced concrete frames with masonry infills. Numerical results obtained with a strut model built in ETABS 2016 software are compared with the experimental results obtained on a full-size model. Tests were conducted in 2018, at the Technical University of Civil Engineering of Bucharest, on a reinforced concrete frame with masonry infills and on a bare reinforced concrete frame under compressive and shear loading. A static pushover analysis method was selected, and results were fairly compatible, even though some differences in the initial stiffness, as well as in the post-yielding stage, were observed between numerical and experimental results. The model is presented, proposing a simple engineering method to be used in calculations.

Concrete is the most used material in construction. By improving the performance of materials and of technologies, concretes with outstanding performances were also developed, in the past two decades. Concrete with dispersed reinforcement represents a new generation of reinforced concrete that combines a good behavior of concrete compressive strength with an increased tensile strength of steel fibers. Using this material, monolithic and prefabricated concrete elements with high mechanical strengths and high durability can be obtained. Technological processes for preparation of concrete with dispersed reinforcement are similar to the conventional methods and do not involve using additional equipment for dosing the dispersed reinforcement. The study aimed the development of road plates made with optimized disperse- reinforced concrete. The first tests were done on plates from the gutter roadway, having a classic reinforcement, using different percentages of fibre reinforcement in the concrete composition, leading to the development of a new optimized economical solution. The results prove the enhanced characteristics of the disperse-reinforced concrete versus conventional concrete, and hence of the developed concrete plates.

Crack analysis is vital to explain behavior of concrete structures. In the present study, an interface element with softening spring is used to simulate cohesive zone model (CZM) in beam to accurately explain the propagation for mixed-mode crack. Modified crack closure integral method is implemented to model propagation of fracture process zone (FPZ) and stress-free region. An element stiffness matrix is used to derive forces in nodes due to normal and shear stress in the FPZ. Size effects such as depth of the beam, effective crack and initial notch are considered in calculation of the FPZ length and crack extension. By using this model, energy release rate is calculated directly by virtual crack closure technique (VCCT) by considering the variation of work done by external loads. The model decreases computational time and complexity for discrete cracks and provides accuracy as compared to other previous research.