Bulletin of the Polytechnic Institute of Jassy, CONSTRUCTIONS. ARCHITECTURE Section

Online ISSN: 1224-3884
Publications
Article
The interpretation, using methodological elements developed in INCERC, of data of instrumental nature obtained in Jassy during the 1986 and 1990 Vrancea earthquakes, is the main goal of the paper. The response spectra (for 12 azimuthally equidistant horizontal directions) of strong motion records, the global parameters which characterize an individual (horizontal) component of a record (effective peak values and corner (control) periods), and the instrumental intensity (global and averaged upon a frequency interval, based on destructiveness spectrum and on response spectrum) are the main numerical results obtained for the seismic records at hand. Finally, an evaluation of results, as well as conclusions useful for the aseismic design of buildings in Jassy, is presented.
 
Parabola-rectangle stress block for rectangular singly reinforced section.
Nondimensional Limits between Ductile and Brittle Failure Classes Steel ξ lim ω lim μ lim
Stress and strain diagram for doubly reinforced section.
Article
In the next decades the design of the civil structures will be ruled by Eurocodes. For reinforced concrete structures the Eurocode2 will became of paramount importance to the design of the structural members. An important aspect of designing represents the relation between stress and strain to the design of the section for structural members. In this respect the EC2 defines 14 classes of concrete with different stress–strain relationships. The first stress–strain relation mentioned of EC2 for design is the parabola–rectangle stress distribution on concrete section, and further the simplified rectangle stress–strain shape is mentioned. Therefore, an aspect of the design, poorly emphasized in the national rule, is the design considering parabola–rectangle stress distribution on concrete section. The exposed issues in this paper concern with the design of the reinforced concrete section subjected to bending using two stress–strain relationships mentioned by EC2, and the differences are underlined. The design to bending using parabola–rectangle stress distribution for rectangular section is largely presented, and also the reliability for a fast designing is emphasized. Design relations for a parabola–rectangle stress distribution on section are mentioned. Also, aspects about the boundary between the single reinforcing domain and the double reinforcing domain are emphasized.
 
Article
The main idea of meshless methods is to approximate the unknown field by a linear combination of shape functions built without having recourse to a mesh of the domain. The computational domain is discretized using a set of scattered nodes. The shape functions associated with a given node is then built considering the weight functions whose support overlaps the one of the weight function of this node; thus, there is actually no need to establish connectivities between the different nodes as in the finite element method. Monte-Carlo integration techniques are promising schemes in the context of meshless techniques. The purpose of the present paper is to implement in EFG a new body integration technique for the evaluation of the stiffness matrix that does not rely on a partition of the domain into cells, but rather points. Numerical examples based on three-dimensional elasticity problems are presented to examine the accuracy and convergence of the proposed method. In this context, Quasi-Monte Carlo integration techniques are used. The results are compared to traditional EFG. Conclusions are drawn concerning the proposed techniques and its capabilities.
 
Article
The procedure Bubble Deck was applied untill now in Europe, in countries like Austria, Belgium, Denmark, Germany, Iceland, Italy, United Kingdom, Holland, also in other continents, in Canada or USA. This constructive system could not be brought into practice in so many projects achieved, only based on fundamental research to prove its validity, therefore tests were made concerning: bending behavior, reaction to shear force, the behavior of mountings, the reaction to fire, the acoustic behavior of these floors and economic analysis.
 
Article
In classical art, form was considered to be reproduced in the most faithful way, representing a naturalistic reality. On the other hand, contemporary art strive to achieve its value by abstraction, and by intelectual and psychological approach. Corresponding to contextual art, the architectural rehabilitation of industrial buildings opens new paths towards form and space abstracting.
 
Article
Integral bridges, or integral abutment and jointless bridges, as they are more commonly known in the USA, are constructed without any movement joints between spans or between spans and abutments. Typically these bridges have stub-type abutments supported on piles and continuous bridge deck from one embankment to the other. Foundations are usually designed to be small and flexible to facilitate horizontal movement or rocking of the support. Integrally bridges are simple or multiple span ones that have their superstructure cast integrally with their substructure. The jointless bridges cost less to construct and require less maintenance then equivalent bridges with expansion joints. Integral bridges present a challenge for load distribution calculations because the bridge deck, piers, abutments, embankments and soil must all be considered as single compliant system. This paper presents some of the important features of integral abutment and jointless bridge design and some guidelines to achieve improved design. The goal of this paper is to enhance the awareness among the engineering community to use integral abutment and jointless bridges in Romania.
 
Article
Researches conducted at the Faculty of Construction in Jassy showed several factors that may help finding technical solutions which will make possible to economically apply acceleration procedures of concrete hardening by thermal treatment with solar energy. It has to be mentioned the fact that the thermal treatment do not exclude, but it is based on the acceleration methods of concrete hardening through composition with or without the usage of different additives -- plasticizer type (to reduce the quantity of water from the concrete) and accelerators for cement binding or hardening. These methods also take into account the climate where the process of hardening takes place.
 
Location of the damaged columns and the composite steel-concrete section of the ground-floor columns. 
a-Variation of the bending moment ratios for the column structures RC/RCS. 
Article
This paper provides initially an overview of some general issues associated with the robustness of structures. Firstly, a brief discussion related to the progressive collapse, from its basic definition, to the inherent difficulties of understanding, analysing and mitigating this phenomenon is presented. Attention is also drawn to the potential sources of abnormal loads that should be examined when designing for progressive collapse performance. In addition, some of the design standards that have been developed, and methods for designing to progressive collapse hazards, are discussed. Finally, a numerical analysis of a four storey reinforced concrete frame structure has been carried out and the results concerning the assessment of a progressively damaged structure are presented.
 
Article
Because of the economic changes from our country and also of the rapid adjusting necessity to the requirement of a market economy, it is observed a huge request for information, and especially techniques, tools, methodologies that would facilitate the managerial activity in any field. In the construction field the problem is even more serious because of specific aspects and of the traditional information system that is very stiff. Formal and bureaucratic, and this makes the adjusting process of specialist to the economic realities to be more difficult.
 
Article
After realizing numerous constructions in the world, which use Bubble Deck concrete slabs with spherical gaps, valuable information were gathered, allowing a rigorous processing and systematization, with the purpose of realizing an experimental and documentary study. The paper presents some experimental programs which refer to concrete slabs with spherical gaps, existing in similar execution and loading conditions as those from a real construction; this implies the realization of a monolithic slab element at a scale of 1:1, which will be subjected to static gravitational loadings in order to determine the deformation (deflection), cracking and failing characteristics. The resultant conclusions will be used in defining the failing mechanisms, very useful in the formulation of an adequate mathematical model. The research proposed in the project offers an answer to the major objectives of the development of calculus methods and existent prescriptions of the concrete slabs with spherical gaps. The realization of the proposed objectives involves documentation activities, theoretical study, collaboration with different other partners, gathering and processing of the results obtained in laboratory and even in situ.
 
Forme de la courbe d'interaction, M-N, pour un poteau complètement enrobé en béton.
Comparaison entre les courbes d'interaction M-N.
Courbe d'interaction plastique M(N).
Article
Depuis près d’un siècle, le système de construction basé sur des portiques en acier ou mixtes acier béton est devenu l’un des types les plus utilisés dans le domaine du génie civil. Plusieurs générations d’ingénieurs se sont préoccupées du développement des méthodes de calcul et des technologies de fabrication relatives à ces structures. En vue d’un dimensionnement optimal des structures, les ingénieurs sont tenus de trouver un compromis entre les exigences structurales de résistance, rigidité et ductilité d’une part, et les objectifs d’utilisation et de fonction relevant d’exigences architecturales d’autre part. Cette article fait une comparaison entre différents méthodes de dimensionnement des poteaux mixtes acier béton, en tenant compte des plusieurs paramètres.
 
Article
For more than one hundred years the construction system based on steel or composite steel -- concrete frames became one of the more utilized types of building in civil engineering domain. For an optimal dimensioning of the structure, the engineers had to found a compromise between the structural exigency for the resistance, stiffness and ductility, on one side, and architectural exigency on the other side. Three monotonic tests and nine cyclic tests according to ECCS loading procedure were carried out in Cluj Laboratory of Concrete. The tested composite columns of fully encased type were subject to a variable transverse load at one end while keeping a constant value of the axial compression force into them. An analytical interpretation is given for the calculus of column stiffness for the monotonic tests, making a comparation with the latest versions of the Eurocode 4 stiffness formula.
 
The computation of the resultant coefficient.
ariation of the wind pressure in the group of solar collectors placed on the building with a total height of P + 4E with B/H = 0.7; H/L = 0.7 (a), placed in separate groups (b), or in a compact group (c).
Air flow upon solar collectors placed on flat roofs: a-general flow, b-visualization of the turbulent flow between the rows of solar collectors.
Article
The interest in the non-conventional energy resources, a consequence of the severe restrictions imposed towards pollution of any kind, arises again the interest in using solar collectors. Implanting them on the terraces of new or existent home residencies, or any kind of other buildings, means to solve a sum of engineering problems, among them being also the stages of safely designing the plane panels for collectors and the sustaining skeleton, made in steel as well as the fixing systems adopted for the interface with the building itself. The necessity of considering the maximum wind speeds actions along other dynamic effects of its turbulence is the result of a many years experience, specially if one must also think in terms of efficiency and costs both for construction and exploitation. The pattern of the wind flow field suffers intricate alterations in the proximity of these collectors placed in the vicinity of the building surface and, in these situations, it is common to test the models at a reduced scale in wind tunnels with atmospheric boundary layers. The experimental study presented in this paper was undertaken in the Laboratory of Aerodynamics of the Faculty of Construction and Building Services in Iaşi and it reveals the results and the conclusions drawn from the analysis of the wind flow over a row of collectors differently arranged in order to evaluate the wind pressure coefficients used in design.
 
Article
The paper describes a calculus procedure to determine the elastic--plastic rotation capacity of steel structural members. The rotation capacity calculus is very important for the design of steel structures exposed to seismic action. The calculus procedure is based on the equivalent elastic--plastic bending moment. This calculus procedure was applied on two types of structural members (beams, columns).
 
Article
This paper refers to the assessment of the performance level of a building for a given seismic hazard level. Building performance level describes the expected seismic performance given by the computation of R3 Nominal Assurance Degree to Seismic Action of the Existing Masonry Dwellings and Monumental Buildings according to the Romanian Norm P100:1992 [1], modified on 1996 with the chapters 11 and 12, until the Part 3 of P100-1:2006 [2], will be performed for the Assessment and Strengthening Structural Design of the Seismic Vulnerable, Existing Buildings, in the frame of SR EN 1998-1:2004 EC8 [3]. The framing of damages into the potential risk degrees has a social and economic impact. Assessment and retrofitting of the existing buildings have represented a huge engineering challenge as a distinct problem versus a new building design. The performance level of a vulnerable existing building shows us the expected seismic performance level due to the classified damages, the pattern of cracks, the interruption of function, the economic losses and the needed interventions, all in function of the importance class of building on next life span of use. On recommends the computation of R (R3) Nominal Assurance Degree to Seismic Action of the Vulnerable Dwellings for the assessing and strengthening design, in comparison to both norms because of the bearing conventional seismic load computed by [1], will result less than the value which will be computed by the Part 3 of P100-1:2006, i.e. the norm P100:1992 is more severe. In the case of the breakable fracture probability of the existing structural masonry members, one recommends a bigger value of ? – reduction factor unless the given values by [1] for a new structure with a high ductility, especially for the deflections calibration on the same limit state.
 
Basic Value of the Behaviour Factor, q 0 , for Systems Regular in Elevation
Response Reduction Factors According to BSLJ 2004
Article
The concept of ductility estimates the capacity of the structural system and its components to deform prior to collapse, without a substantial loss of strength, but with an important energy amount dissipated. Consistent with the „Applied Technology Council” (ATC-34), from 1995, it was agreed that the reduction seismic response factor to decrease the design force. The purpose of this factor is to transpose the nonlinear behaviour of the structure and the energy dissipation capacity in a simplified form that can be used in the design stage. Depending on the particular structural model and the design standard the used values are different. The paper presents the characteristics of the ductility concept for the structural system. Along with this the general way of computing the reserve factor with the necessary explanations for the parameters that determine the behaviour factor are described. The purpose of this paper is to make a comparison between different international norms for the values and the distribution of the behaviour factor. The norms from the following countries are taken into consideration: the United States of America, New Zealand, Japan, Romania and the European general seismic code.
 
Article
Ce qui suit représente une approche pertinente des aspects actuels du développement de Bucarest et de la perspective de la capitale de la Roumanie de devenir, en 2025, une véritable métropole. Dans la premiere partie de cette étude la metropole est définie en tant qu’une localité qui a plus de 200,000 habitants, qui est directement connectée au continent européen (aéroport international) et qui attire des institutions internationales et des activités multinationales de production abstraite (services représentés par des banques, des quartiers généraux et des filiales de grandes compagnies, etc.) et de production concrete (industrie d’excellence). Si l’on envisage les objectifs stratégiques de développement de chaque localité, compte tenu du niveau d’évolution, Bucarest se remarque par: a) un sous-dimensionnement évident de la Région Bucarest-Ilfov (1,821 km$^2$) par rapport a d’autres régions, comme par exemple la Région Métropolitaine de Budapest (8,930 km$^2$) ou la Zone Métropolitaine de Prague (3,913 km$^2$), se situant, compte tenu des dimensions réelles, entre les agglomerations urbaines de Budapest (2,536 km$^2$) et de Prague (1,667 km$^2$); b) un évident sous-dimensionnement du territoire du Municipe de Bucarest, qui a une densité d’habitants au moins double comparativement a d’autres capitales (Bucarest--8,893 habitants/km$^2$, par rapport a Prague, Varsovie et Budapest--2,418, 3,284 et, respectivement, 3,554 habitants/km$^2$), ce qui explique l’extension de certaines fonctions au territoire des communes environnantes et la nécessité future d’un développement corrélé a celui des communes de l’agglomeration urbaine. On présente, également, le cadre général de développement économico-social du Municipe de Bucarest, l’histoire du développement de la localité, sa position géographique ayant des influences directes sur l’évolution et la tendance économico-sociale dans la période 1990--2006. Dans un travail prochain, on présentera des aspects relatifs a la place de la Capitale dans l’économie du pays, son potentiel économique et certains éléments concernant la qualité de la vie et le comportement des habitants de la Roumanie.
 
Article
L’article ci-présent représente la suite de l’article paru dans le numéro antérieur de la revue et présente des aspects concernant les conditions que Bucarest doit remplir pour qu’a l’horizon de l’an 2025 il puisse acquérir le statut de métropole européenne, ayant un rôle spécifique régional, continental et intercontinental. L’économie du Municipe de Bucarest sera prioritairement axée sur des activités de services, sphere qui concentrera une grande partie de la population occupée et ou l’on réalisera quelque 85% du total du Produit Intérieur Brut de la Capitale, a l’horizon de l’an 2025. La qualité de la vie, évalue compte tenu du degré de développement des activités et des services directement visant assurer une vie décente a la population (degré exprime par des indicateurs économico - financieres), ainsi que par les appréciations faites par la communauté, connaitra des améliorations considérables. Pour que le Municipe de Bucarest puisse parcourir toute la trajectoire qui lui assure la possibilité de devenir, d’une Capitale d’envergure européenne, une Capitale européenne d’envergure, ayant les traits caractéristiques d’une authentique métropole du troisieme millenium, il faudra remplir les conditions sine-qua-non suivantes: réaliser des mutations profondes de l’état économique de la Capitale et de sa population; moderniser progressivement le profil économique de Bucarest, pour obtenir des décalages importants dans le positionnement du secteur tertiaire et des industries faisant appel aux nouvelles technologies; structurer, afin de renouveler, le domaine de l’équipement commercial et a services, tout en établissant de nouveaux équilibres entre le commerce de grandes surfaces et le commerce de proximité, a divers degrés de spécialisation; amener, a un standard européen de qualité, les rues des zones extra centrales (pavage, réseau d’eau et canalisation, gas); revigorer certains services traditionnels pour la population de Bucarest: services de réparations, confectionnement sur commande, entretien du patrimoine immobilier; approfondir les facteurs de qualité de la vie, des relations interhumaines et du développement de la culture; repenser la trame des rues, créant de nouvelles axes de circulation majeure, y compris un systeme annulaire de transport, connecte aux corridors européens de transport IV (Vienne – Budapest – Bucarest) et VII (Liov – Bucarest – Giurgiu); créer un systeme d’arteres routieres et de transport public avance (passages dénivelés, moyens modernes de transport); réhabiliter le Centre historique et rénover les bâtiments anciens; organiser des activités d’ampleur européenne, constituer un puissant centre commercial et d’affaires dans cette partie de l’ Europe; finaliser les aménagements sur les rivieres Arges et Dambovita: raccorder Bucarest, apres 2015, a la principale artere transeuropéenne de navigation Rhin-Main-Danube.
 
Article
The improvement of causeway’s bitumen adhesiveness is becoming a current practice in our country, especially when is used acid (siliceous) aggregate. One of the most important properties of bitumen is its adhesiveness to aggregate, and this property determine the using of bitumen in causeways area. Usually the adhesiveness is defined as the capacity of a binder to cover an aggregate without dispersing itself when touching the water or the traffic aggressions. Therefore, the adhesiveness additives are products that improve the adhesiveness of the bitumen to a certain aggregate. The used additives – ADETEN type (A01 and A03) have a high stocking stability, a low toxicity degree toward the amine, diamine, polyamine-based additives and are liquid products perfectly compatible with all bitumens and easy to use, in comparison to the paste or solid additives, which must be made liquid to be used. But a very important condition, which must be fulfilled by these promoters is the heat-resisting condition.
 
Article
The results of laboratory tests for two additives: ADIROL ALCAMID F and ADIROL ALCAMID FS are presented. Three mixtures were made in laboratory, with two types of bitumen of four dosages each, in order to assess characteristic physical and mechanical values of mixtures made with bitumen having 0.5% additives. The analysis of obtained results shows a substantial improvement of the characteristic physical and mechanical values of these mixtures as compared to mixtures made with non-additive bitumen.
 
Article
For determining the adherence stresses concrete-to-concrete a device for wrestling of added layer to the support is used, according to the Romanian norms. The connection to the determination apparatus is realized by a metallic plate bonded with special adhesive. The value of this stress is in many cases bigger than the adhesive strength, therefore the metallic plate detaches oneself before the separation of the added concrete.
 
Article
Mechanical joining techniques are used in construction industry all over the world on a daily basis. A further method of joining has proven to be highly successful – adhesive bonding. Known for thousands of years, adhesive bonding has become as important as other joining techniques as a result of the pace of developments in recent years. In many areas, this bonding technology has become a key technology. Virtually, all solid materials can be connected with one another using adhesives. Although bonding fibre reinforced polymeric composites to the concrete substrate is a relatively simple technique, the proper installation of the fibre reinforced polymeric composites is essential to ensure the adequate performance of the hybrid system. Since the installation procedures differ from one system to another, appropriate specifications will be clearly presented. The paper will include requirements to provide a quality joint assembly, meaning the special pre-treatments of the concrete surface. The material to be bonded is cleaned and prepared so that adhesives can adhere better to them.
 
Article
The estimation of the capacity of coverage in the laboratory may be made visually as well. The operator ’s subjective perspective, the angle of view, the luminosity, the nature and colour of aggregates are many factors that may influence the result. The computer-assisted image analysis qualifies and quantifies objectively enough the capacity of coverage of bitumen on aggregates, removing any exterior influences. It is a simple, repeatable and reproducible used method.
 
Article
In recent decades, tremendous success has been achieved in the advancement of chemical admixtures for Portland cement concrete. Most efforts have centered on improving the properties of concrete with minimal investments by ready-mix suppliers and contractors in the way of specialized equipment or special skills and education of their labor forces. This approach has resulted in construction cost reductions and universally accepted ready-made remedies for unexpected problems during construction. The behavior of concrete improved with superplasticizers additives is studied.
 
Article
Whether built in the 17th or in the 20th centuries, adobe buildings share common problems of maintenance and deterioration. These types of buildings represent today in Romania a traditional house for country people. It also makes recommendations for preserving adobe buildings. By its composition, adobe construction is inclined to deteriorate; however, the buildings can be made durable and renewable when properly maintained.
 
Article
Concrete is the most undisputable and indispensable material being used in infrastructure development throughout the world. Umpteen varieties of concretes (FAC, HVFAC, FRC, HPC, HSC, and others) were researched in several laboratories and brought to the field to suit the specific needs. Although natural fine aggregates (i.e., river sand) are so far and/or will be superior to any other material in making concrete, their availability is continuously being depleted due to the intentional overexploitation through out the Globe. Hence, partial or full replacement of fine aggregates by the other compatible materials like sintered fly ash, crushed rock dust, quarry dust, glass powder, recycled concrete dust, and others are being researched from past two decades, in view of conserving the ecological balance. In this direction, an experimental investigation of strength and durability was undertaken to use “Spent Fire Bricks” (SFB) (i.e. waste material from foundry bed and walls; and lining of chimney which is adopted in many industries) for partial replacement of fine aggregate in concrete.
 
Article
In the present paper is analysed concrete behavior from strength structure elements, subjected to combined sulphatic and magnesian aggressive actions. In order to clearly relieve cement influence regarding corrosion behavior and to be as close as possible of concrete structural characteristics, tests are realized on standard mortars, which from compositional point of view are mocro-concretes. These were used different W/C ratios in order to obtain different structural characteristics, knowing that in the first period after casting, when concrete porosity is sensibly higher, corrosion process is more emphatic, with subsequent negative effects. It was taken into account the fact that sulphatic corrosion effect appears after a long duration of aggressive agent action, in the present paper proposing a three year duration for aggressive attack. In the same time it was considered the fact that usual cement for structural elements is composite cement type CEM II/A-S 32,5, studying combined sulphatic and magnesian corrosion evolution on a large type of micro-concrete compositions with different compactness and aggressive agent concentrations.
 
Article
Several micro-concrete recipes with varied composition characteristic are presented, in which the binding material is a composite cement of II/ A-S 32,5 type (Pa 35 equivalent) and their behavior in to analyse their behavior in environment with magnesian aggressivity, when the composition factor varies.
 
Article
Under the conditions of present society in which providing an optimum interior comfort is confronted with the necessity of the energy consumption reduction, solving this problem depends on the factors which contribute to the achievements of this comfort. Modern buildings -- implicitly teaching unit -- may be equipped with installations which have low energy consumption, respective a heating, cooling and ventilating integrated system with heat pumps system which can assure all the required comfort conditions. This paper underlines the necessity to use the heat pump in heating system for a teaching unit, energetic and economic guides and the possibility to increase them when using cooling and heating mixed. The solution of heat pumps for heating of the teaching unit and the energetic and economic advantages of the system is made in study.
 
Article
The present paper proposes the analysis of the efficiency of water to air heat exchanger with heat pipes for the mechanical ventilation system. The performed study is based on the necessity of the unconventional energy forms capitalization, increasing of the energy efficiency and the energy consumption decrease in concordance with the sustainable development concept.
 
– Heat flux, Q.  
– Convective heat transfer, α 1 water .  
Article
The present paper presents a heat-recovery apparatus with heat pipes, originally designed by the authors for the controlled mechanical ventila-tion systems to ensure the comfort in the insulated buildings. The paper highlights a close correlation between the heat pipes heat exchangers and the concepts of thermal comfort, energy economy, environment, etc.
 
Article
Une nouvelle classe de fluides composée par des nanoparticules métalliques en suspension dans un liquide, appelée nanofluide, est apparue récemment. Quelques études numériques et expérimentales ont montré que ces nouveaux fluides possedent une puissance d’échange thermique remarquable, comparée aux liquides conventionnels. L’étude qui suit a le bout de montrer par voie expérimentale les performances thermiques d’un nanofluide composé d’oxyde d’alumine dispersé dans de l’éthylene-glycol en différentes concentrations, allant de 0 a 2%. Le dispositif expérimental est un échangeur a tubes concentriques en inox, avec écoulement du fluide chaud dans le tube central et du fluide froid dans le tube annulaire. Les résultats obtenus montrent que la présence des nanoparticules dans le fluide de base a pour effet une augmentation considérable du transfert thermique.
 
-Schematic representation .
– Experimental set up. 
shows the variation of viscosity of the nanofluid considered as function of the temperature as well as of the particle volume concentration.
-Variation of Nusselt number.
-Variation convection.
Article
Recently, a new class of fluid made up of metal nano-particles in suspension in a liquid, called nanofluid, appeared. Some numerical studies have shown that these new fluids have a higher heat transfer performance, compared with the conventional liquids. In the present study, we have attempted to study, by experimentation, the thermal performances of a particular nanofluid composed of aluminum oxide ($gamma$ce{Al2O3}) particles dispersed in water for various concentrations ranging from 0 to 4%. The experimental set up is a coaxial exchanger, which is destined to solar application, in which the heating liquid used is the nanofluid studied.
 
Article
The sanitary comfort and the effective cost of maintenance in the civil buildings (block of flats) are badly affected by the absence of the consumption hot water recirculation. From the technical point of view, the classical solution imposes the doubling of the transport and distribution pipes on the entire route, between the source and the consumption points. The materialization of the solution requires important financial investment, discouraging most of the time and the postponement of the problem solving with important consequences. This paper proposes an alternative technical solution which limits to a minimum the intervention, only in the interior hot water distribution system.
 
Article
High strength concretes incorporating large amounts of silica fume (SF) are analyzed for different types of admixtures. Properties of fresh and hardened concrete were analyzed for dosages of SF between 30% and 50% and were compared with 10% SF. Influence of admixtures in the case of large amounts of SF is significant only in the case of fresh concrete. In the case of hardened concrete, for admixture type super plasticizer containing calcium sulfonat can be obtained the best results.
 
b on a représenté l'organigramme des sous-programmes qui sont utilisés dans le programme principal CORMAT de correction de la matrice de rigidité d'un modèle de calcul en utilisant comme données d'entrée seulement celles enregistrées pendant les essais expérimentaux.  
– Validation du programme CORMAT: a – le modèle expérimental; b – l'emplacement des traducteurs.  
Article
La procédure de correction d’un modele analytique adopté pour une structure de construction est précédée d’une comparaison entre le set des données expérimentales et celui des données analytiques, pour une vérification préliminaire concernant la correspondance raisonnable entre ces données. Pour l’identification dynamique des parametres ont été élaborées diverses méthodes de correction des matrices de rigidité et de l’amortissement qui ont a leur base la méthode des moindres carrés dans le domaine des fréquences. L’algorithme proposé a comme résultat la correction de la matrice de rigidité d’un modele de calcul en utilisant comme données d’entrée seulement celles enregistrées pendant les essais expérimentaux.
 
Article
A new method for the seismic risk identification is proposed based on the average measure of the expected annualized losses from earthquake occurrence. We show up how can be identified the risk for insurance decisional purposes. The analysis is useful for insured as well as for insurance company. When risk is considered from time dynamical perspective we emphasize the advantage of diversification for earthquake risk mitigation.
 
Article
L’objectif visé dans cette étude est la définition et la validation des modèles de simulation hydraulique et thermique des installations de chauffage à eau, bitube, à circulation forcée, avec des radiateurs équipés de robinets thermostatiques. Dans l’environnement du logiciel de simulation TRNSYS, le modèle de simulation de l’installation de chauffage, couplé à un modèle représentatif d’un bâtiment multizone, est ensuite utilisé pour évaluer les économies d’énergie apportées par la mise en place des pompes à vitesse variable. L’étude simulée du fonctionnement et des performances est réalisée pour une installation de chauffage d’un petit bâtiment tertiaire qui aboitte des bureaux. Les simulations sont effectuées dans l’ensemble de la saison de chauffage à l’aide de fichiers météorologiques au pas horaire. L’analyse porte principalement sur les économies d’énergie apportées par la mise en place d’une pompe à vitesse variable avec les deux types de réglage (H=const. et H -- proportionnelle).
 
Article
General numerical methods based on the discretization of the surface between structure and soil in finite elements are developed and, by their help, the stiffness matrix is determined. There are considered the medium model of linear elastic, homogeneous and isotropic half-space and anisotropic half-space, respectively. In case of rigid structures or with rigid base, it is essentially for their response evaluation to know the stiffness coefficients.
 
Article
The art of film, the most popular art of the 20th century, can represent for architecture a means of teaching and promoting its specific values, an inspirational source and a good example of efficient and accessible cultural communication. The architecture presents many resemblances with the world of film regarding the concept and space exploring for communicating some ideas or concepts. Both film and architecture have narrative qualities, work with the world of illusions and representations and compose various elements in order to carry on certain significances. The film makers are making available the suggestive and semantic potential of architecture to render states and attitudes, to outline certain meanings or to emit opinions and comments on political, psychological and social issues.
 
Article
The modern landscape architecture being a profession that has an important impact on the environment, tries and succeeds to cover a very wide area. Because of its complex preoccupations area, the profession of the landscape architect may find itself in a nebula regarding the comprehension and the reaction of the public and cities mayors towards it. The landscape architecture has as purpose the realization of an ambience that is favourable to the human life progress, having in view the increasing of life’s quality and of the urban comfort, the maintenance of the ecological equilibrium. Despite the complexity of its preoccupations, the landscape architecture has been often lowered to the same level with the exclusive arrangement of green spaces.
 
Article
The theory architecture considers the whole sphere of architecture as a study matter and has applications in fields belonging both to the practice and the knowledge. These are: architectural experience and architectural output (designing), to which we must add the architectural research, the history of architecture and the architecture criticism. The theory enables us to understand the architectural experience, our perceptions in the „lived” architecture. It also defines the factors which determine the creation of an architectural work and makes possible the critical estimate of the quality of a certain solution in a concrete case. The theory gives a conceptual base to the architectural research, pointing out the problems and putting its results in order; without o coherent theoretical basis, both architectural research and history of architecture lead only to knowledge without profoundness. Each of these application fields goes through its own dynamic process, and, in its turn, the theory of architecture, having multiple interconnections with them, is a complex subject, in a continuous evolution.
 
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Performing the diggings nearby and/under the implantation quota of some existing buildings may trigger on the structural elements and/or over the arrangement site states of efforts or additional deformations, which may diminish the reinforcing capacity and/or loss of local/general stability given certain conditions of induced load. The paper herein presents situation generated by the execution of a section of domestic sewage, near and under the implantation foundation of a retaining wall having the role of maintaining stability of the arrangement site of residential buildings.
 
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Romanian higher education began a long time ago, having its own national specificity but being also influenced by the education from other developed countries. Between 1813 -- 1840 Gh. Asachi created the School of Terminal Engineering, establi-shing the foundations of the Technical Engineering University. In Moldavia, higher education in engineering, in the field of roads and bridges, coincides with the official opening of the Faculty of Construction of Jassy, in 1941, as part of the Polytechnic Institute, today the „Gheorghe Asachi” Technical University. Over the years, this type of education has evolved and developed, under the influence of schools of engineering such as The School of Bridges and Roads in France. The French School of Bridges and Roads was created by a decree of the king, on the 14th of February 1747. In two and a half centuries, it has trained about 15,000 engineers, who accomplished great works both in their native country and abroad. The reputation of this school is based especially on the discoveries, the accomplishments and the activity of these engineers, who have a great impact on the development of this institution. Most of these engineers did not go down in history (we seldom know the name of the person who built a bridge or a road). We remember some of them by a formula, a machine, a plate on a road, without actually knowing who is the person behind the name. Shaping their portraits, we could bring them back to the memory of the public, emphasizing the common aspects of their professional training at the School of Bridges and Roads. A free professional background, of a high scientific level, comprising a lot of practical issues, based on public transport in the beginning, where reflection and action play an important part. Except a lot of great scientists (among them, a Nobel prize laureate), inventors, entrepreneurs, engineers with prestigious accomplishments, there are also politicians (even a president), writers, a navigator. The selection of these personalities was difficult and can be contested. It was not intented to establish a hierarchy, but only to create a gallery of portraits, the only criterion taken into account being the exclusion of those engineers who are still alive. Unfortunately, there is no woman among these portraits, because their access was only permitted in 1959 for civil engineers and in 1975 for the others. We hope that this anomaly will be redressed in the paper celebrating 300 years of existence of this school. After a quarter of a millennium, in the 21st century, the oldest civil school of engineers in the world, created during the reign of Louis XV, remains what it has always been: a way of modern training in the benefit of the nation and of society, having the ambition to instruct a quality personnel, able to adapt to the problems and needs of its epoch. With a prestigious heritage, the School of Bridges and Roads has evolved and transformed during its 250 years of existence, always remaining proud of its past and at the same time open towards the future. Many authors have already mentioned the history, rich in events, of this institution. We shall try to describe it concisely in the present paper. We shall present some portaits of well-known engineers: great constructors, inventors, scientists, making themselves known in other areas than their initial training, they illustrate a less known aspect of the life of the roads and bridges engineer, a rich, intense, varied life and activity. The objective of this paper is to allow a better understanding of what has been, over the past 250 years, the french School of Roads and Bridges.
 
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The paper is structured in three main parts. In the first part, there is a classification of the critical systems existing in the urban background, which are part of an extremely urging informational infrastructure in case of a seismic event. The critical systems are identified as those systems whose malfunction may lead to disasters affecting the human being and the environment as well. The second part focuses on the underground pipe networks, presenting at the same time, their classification into three categories of great importance in case of an earthquake, and last but not least, the final part contains the presentation of an analysis methodology of seismic behavior of the underground pipe networks, considered as part of the existing critical systems, in case of a seismic event in an urban area.
 
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Traditional steel based reinforcement systems for concrete elements are facing with serious problems mainly caused by corrosion due to chemically aggressive environments and salts used in deicing procedures, especially in case of bridge steel reinforced concrete girders. Also in some cases special applications require structural members with magnetic transparency. An alternative to this major problem has recently become the use of fiber reinforced polymer (FPR) composite bars as internal reinforcement for concrete beams. The particularities of their mechanical properties are making the design process a difficult task for engineers, numerous research centers being involved in correcting this situation. The general aspects concerning the conceiving of FR.P reinforced concrete beams are firstly analyzed, compared to those reinforced with steel bars. Some results of a Finite Element Analysis, as part of a complex program which also implies full scale testing of FRP reinforced beams subjected to bending, are given and discussed in the paper. The low elasticity modulus presented by glass fiber reinforced polymer (GFRP) bars does not justify its use from structural point of view when deflection is the limiting condition but for corrosive resistance reasons and special electromagnetic properties this system can be promoted.
 
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The author’s experimental researches presented in this paper were focused on the building materials obtained by using ultra-fine fly ash and silica fume (like heavy mortars or compacted lightweight concretes). From experimental determinations there have been studied the following characteristics: the water absorption in function of mass, apparent density, tensile and compression strength (at 7 and 28 days), technical efficiency at 28 days and shrinkage.
 
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This paper presents the lab results for four types of filler used in producing the asphalt mixture in Romania, as well as other physical-chemical characteristics of a new type of filler, derivate of the grinding of the bituminous shists through a ball mill/crusher. Knowing these physical-chemical characteristics is crucial for asphalt mixtures due to the complex purpose of the filler.
 
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The high costs of the quarry crushed aggregates (producer costs to which additional railroad transport costs are taken into account) result in the fact that at large distance away from quarry lesser amounts of chippings and crushing sands are provided only. The initiation of the crushed aggregates production manufactured out of steelworks crushed slag. Lidonit, at a competitive delivering price, has led to the first series of laboratory tests. In the first stage two asphalt concrete mixtures were made in cube-shaped and cylinder-shaped (Marshall) test-tubes on which physical and mechanical characteristic values are determined. The results of these first tests outlined the real opportunity of using these products in supplying the roads and streets with asphalt mix for pavements.
 
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The first coloured bitumen was obtained by using bitumen from Peru and then bitumen from the Middle East, with a low content of asphaltenes, also called "colourable" bitumens. The colours obtained by adding iron oxides led nevertheless to dark colours, due to the presence of asphaltenes. Nowadays the coloured asphalt is obtained from synthesis binders with translucent aspect. The colours are obtained by adding inorganic pigments, mainly iron oxide for red, chromic oxide for green, titanic dioxide for white. The properties and behaviour of the coloured bitumen during its lifetime are comparable with the ones of classic bitumen, sometimes even better.
 
Top-cited authors
Nicolae Taranu
  • Gheorghe Asachi Technical University of Iasi
Iancu-Bogdan Teodoru
  • Gheorghe Asachi Technical University of Iasi
Gabriel Oprisan
  • Gheorghe Asachi Technical University of Iasi
Luca Septimiu
  • Gheorghe Asachi Technical University of Iasi
Ionut Ovidiu Toma
  • Gheorghe Asachi Technical University of Iasi