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  Numarul 1/2016

Volumul 7 (2016), Nr. 1

Efecte produse de montarea unei noi termoizolatii externe asupra cladirilor cu pereti din zidarie de caramida plina presata
Effects due to new external thermal insulation fitting on the existing solid brick masonry building
Daniel Stoica, Ion Mierlus-Mazilu

In ultimul timp s-a folosit foarte des ideea de aplicare a unei termozolatii exterioare perimetrale la cladirile existente, indiferent de tipul de pereti exteriori. Aceasta lucrare, deocamdata, se refera numai la cladirile cu pereti exteriori din zidarie. Ideea a pornit de la discutii secventiale cu domnul profesor ASANACHE. Din nefericire LA ACEA VREME nu stiam cum sa facem iar domnul profesor a trecut intre timp la cele vesnice… Acum stim, dar munca e infinit mai grea fara dansul…

Lately often used the idea of applying an external perimeter thermal insulation for an existing buildings, regardless of the type of exterior walls. This work, is just about solid brick masonry buildings exterior walls. The idea came from sequential discussions with Professor ASANACHE. Unfortunately at THAT time we did not know how to do and unfortunately the professor has just passed away ... Now WE know, but the work is infinitely more difficult without him...

Performanta energetica (Doset-PEC și Pre-Design Tool) vs. performanta exergetica (Pre-Design Tool) - Cladiri de locuit unifamiliale –
Energy Performance (PEC Doset and Pre-Design Tool) vs. Energy Performance (Pre-Design Tool) - Single-family residential buildings -
Brata Silviana, Cotorobai Victoria, Dobosi Ioan Silviu, Bistran Ioan

La nivelul Romaniei, Comunitatii Europene dar si global, in ultimul deceniu se pune un accent deosebit pe promovarea politicilor de eficientizare energetica si ecologica a cladirilor de locuit, cei mai mari consumatori de energie. In acest sens s-au promovat Directivele europene 2010/31, 2006/32/CE si 2009/28/CE care impun exigente speciale cladirilor. In prezenta lucrare se prezinta o metoda de analiza a performantelor energetice ale cladirilor, respectiv metoda de evaloare a joasei exergii care permite o mai corecta si detaliata analiza, si care ofera un instrument de selectie performant pentru noile cladiri NZBE. Se prezinta si un studiu de caz pentru Romania.

In Romania, the European Community but also globally in the last decade put particular emphasis on promoting energy efficiency and environmental policies of residential buildings, the largest consumers of energy. In this regard they have promoted European Directives 2010/31, 2006/32 / EC and 2009/28 / EC imposing special requirements of buildings. This paper presents a method for analyzing the energy performance of buildings or assess a low exergy method that allows a more accurate and detailed analysis, and provides a powerful tool for new buildings NZBE selection. It presents a case study for Romania.

Pornirea incalzirii intr-o incapere rece. Comportamentul termic al unui perete exterior tristrat
Turning the heating in a cool room. The thermal behavior of a three-layer outer wall
Prof. dr. ing. Florin Iordache

Lucrarea urmareste in regim termic nestationar declansarea procesului de incalzire a unui perete rece format din 2 categorii de straturi : un strat masiv de beton armat si unul sau doua straturi de izolatie termica plasate pe suprafetele stratului de beton armat. Se prezinta o posibilitate simplificata de modelarea a proceselor de transfer termic in regim nestationar in 2 variante de incalzire a peretelui. Se stabilesc rezultate privind comportamentul termic dinamic al peretelui in 2 cazuri de aranjare a straturilor peretelui si anume stratul de izolatie termica la interior in cazul intai si apoi in cazul al doilea stratul de izolatie termica la interior. Rezultatele obtinute au vizat evolutia in timp a temperaturilor, densitatilor de flux termic si a densitatilor de energie pe fetele si in interiorul peretelui.

The paper aims in unsteady state thermal regime to watch start the heating process of a cold wall with two or tree layer consists of two categories: a massive layer of reinforced concrete and one or two layers of insulation, placed on reinforced concrete surfaces. It shows a simplified process modeling possibility of unsteady state heat transfer in 2 scenario to heating the wall. The results establish the dynamic thermal behavior of the wall in 2 cases the arrangement of layers : the case first - the wall insulation layer on the inner surface of the reinforced concrete layer, and the second case – the layer of insulation on the outer sufaces of the reinforced concrete layer. The results focused on the time evolution of temperature, heat flux density and energy density on the surfaces and inside the wall.

Concepte de proiectare şi dezvoltare regenerativă la clădirile civile rezidențiale
Regenerative Concepts of Design for Residential Buildings Development
Paul-Dorian Parincu, Gabriela Maria Atanasiu

Articolul prezinta analiza calitatii constructiilor rezidentiale existente pe baza criteriilor de performanta ale utilizatorilor, urmarind tranzitia conceptelor de proiectare de la “cladirea verde”, la dezvoltarea sustenabila si regenerativa. Procesul adoptat in constructia unei societati moderne a generat o serie de disfunctionalitati in mediul in care traim, conceptii adanc inradacinate in cultura noastra. Strategiile cladirilor verzi, obiectivele de performanta si metodele de evaluare asociate subliniaza in prezent modalitatile si masura in care cladirile ar trebui sa atenueze epuizarea resurselor si degradarea mediului la nivel global si local. Prin contrast, notiunea de proiectare si dezvoltare regenerativa evidentiaza o relatie co-evolutiva, un parteneriat intre oameni si mediul natural.

The article presents the analysis of the quality of the existing residential contructions based on the performance criteria imposed by the user, following the transition of the design concepts from the green building to sustainable and regenerative designing development. The process adopted in the construction of a modern society has produced a number of failures in the environment in which we live, concepts deeply rooted in our culture. Strategies of green buildings, performance objectives and assessment methods currently associated emphasise the methods and the extent to which buidings should reduce resource depletion and environmental degradation on a global and local level. On the other hand, the concept of regenerative design and development shows a co-evolutionary relationship, a partnership between people and natural environment.

An estimation of change of parameters of indoor microclimate during term of exploitation of building and engineering systems
Viktor Petrenko, Denys Volchok

The lifetime of various buildings has a different age, which is from 25 to 50 years, and after additional studies and examinations may be extended on longer term. The lifetime of engineering systems, depending on their type and purpose is 10 to 25 years, and in some cases much more. Parameters of microclimate, on which the building is designed, do not include lifetime or building envelope or engineering systems. However, there are aging and sometimes destruction of some of the elements that negatively affect the change in the parameters of the microclimate sanitary norms during the operation of the building and its engineering systems. Estimation of parameter changes of indoor microclimate during the life of the building engineering systems will monitor their fluctuations and affect their adjustment to maintain required parameters.

Numerical modeling of wind flow over different terrain types
Angel Terzieva, Rositsa Velichkovaa, Kiril Mavrova

Worldwide, the amount of energy produced by the power of wind rapidly increases. The installed capacity of wind farms has increased nearly 60 times for the last 20 years. The small wind turbines that have been installed 20 years ago are at the end of their operational life. Pretty soon they need to be replaced with bigger ones, which leads to a completely new micro-sitting of the wind farm. In case of a flat terrain the micro-sitting can be easily performed since the wind parameters (wind speed and direction) are known for a long period of time. For a hilly or complex terrains a couple of assumption needs to be made in order to have the most reliable results. Improvement of the results from numerical study is possible with the adjustment of the uncertainty of the used models. Some restrictions about the size of the domain where the numerical procedures will take place are also discussed.

Aspecte caracteristice privind analiza structurala a cladirii de birouri Bucharest One
General considerations regarding the structural analysis of the office building Bucharest One
Claudiu-Anton URSU, Viorel POPA, Mihai DRAGOMIR, Dragos COTOFANA, Serban DIMA, Vasile-Virgil OPRISOREANU

Articolul prezinta metodele de analiza utilizate la proiectarea cladirii de birouri Bucharest One. Cladirea are o inaltime supraterana de 120m fiind formată din trei subsoluri, parter, mezanin, 23 etaje si etaj tehnic. Construcția este amplasata in Bucuresti, strada Barbu Vacarescu nr. 201, fiind formata din două corpuri cu functiuni diferite. La proiectarea si verificarea structurii de rezistenta s-au folosit metode avansate de calcul structural utilizand programe specializate cu elemente finite. Modelele de calcul includ atat suprastructura cat si infrastructura, cu considerarea intrectiunii terenstructura. Datorita inaltimii constructiei, formei in plan a acesteia si clasei de importanta in care se incadreaza s-au utilizat metode de calcul elastic si inelastic (calcul static neliniar si calcul dinamic neliniar). Analizele efectuate s-au realizat cu ajutorul programelor de calcul Etabs 2013 si Perform 3D. Verificarea deplasarilor laterale si dimensionarea preliminara a elementelor suprastructurii s-a realizat pe baza unui calcul elastic, prin utilizarea metodei de calcul modal cu spectre de raspuns. Evaluarea performantei structurale si stabilirea eforturilor maxime la nivelul infrastructurii s-a realizat pe baza analizelor static si dinamic neliniare.

The document presents the analysis methods applied in the structural design of the office building Bucharest One. The tower has a total height of 120 m above ground, three basements levels, ground floor, mezzanine, 23 floors above and one technical floor. It is located in Bucharest on Barbu Văcărescu Street no. 201 and consists of two buildings with different functions. Advanced analysis techniques employing finite element specific software were considered in the structural design. The computation models include both the upper structure and the basement, taking into consideration the soilstructure interaction. Considering the height of the building, its shape and the importance class, elastic and inelastic computations were performed (static and dynamic nonlinear analysis). The analysis was done using Etabs 2013 and Perform 3D software. The verification of the lateral displacements and the dimensioning of the structural elements were performed by elastic response-spectrum modal analysis. The assessment of the structural performance and the maximum forces in the infrastructure were carried out by static and dynamic nonlinear analysis.

Consolidarea Edificiilor Existente Utilizand TiranTi Metalici
Existing Monuments Rehabilitation Using Steel Tie Rods
Madalin COMAN, Mircea CRISAN, Dragos MARCU, Mihai A. GANEA

Prezentul articol reprezinta un studiu de caz asupra utilizarii tirantilor metalici pentru sporirea proprietatilor de ansamblu ale zidariilor vechi. Pentru aceasta sunt trecute in revista lucrari reprezentative de consolidare la care au fost utilizati in regim de pionierat tiranti metalici. Imobilele analizate au structura preponderent din zidarie, ajungand ca la inceputul lucrarilor aceasta sa se afle intr-o severa stare de degradare. Edificiile studiate sunt Biserica Evanghelica din Sibiu, Biserica Sfintii Arhangheli din satul Cicau, Manastirea din satul Sadova, Palatul de Justitie din Bucuresti si Palatul Patriarhiei. Tirantii metalici au fost folositi in toate aceste cazuri pentru consolidarea boltilor, asigurarea efectului de saiba semirigida si pentru sporirea ductilitatii peretilor, reprezentand o metoda de consolidare ce merita insusita de intregul corp profesional specializat.

This paper represents a case-study upon the usage and implementation of steel tie rods for the strengthening and rehabilitation of old masonry structures. The review focuses on four representative structural strengthening projects that used tie rods as a pioneering approach to building strengthening. All buildings are based on masonry structures, which were severely affected when restoration projects commenced. The analysed structures are the Lutheran Cathedral of Sibiu, the Saint Michael & Gabriel Church of Cicău, the Sadova Monastery, the Bucharest Palace of Justice and the Patriarchate Palace. For each of these cases, tie rods were used for vault strengthening, for enhancing the overall structural seismic response, and for increasing the ductility of masonry walls. Such a rehabilitation technique is worth being considered and grasped by any member of the professional body.

Analiza subracirii fluidelor frigorifice in instalatiile frigorifice pentru climatizare cu vaporizare directa
Analysis subcooling refrigeration fluids in refrigeration for direct evaporative air conditioners
drd. ing. Catalin Georgian NEGRUTIU, Prof. Dr. Ing. Dragos HERA

There are a many possibilities to subcool the refrigerants. In this article are analysed these alternatives with advantages and corresponding disadvantages. For different refrigerants used for HVAC applications it will be presented the subcooling effect on the performance of the refrigeration system (COP, Qo).

Influenta conditiilor de contract FIDIC asupra managementului financiar al proiectelor de constructii
The influence of FIDIC conditions of contract on the financial management of construction projects
Augustin Purnus, Constanta-Nicoleta Bodea

Schimbarile economice din ultima decada atat la nivel global, dar mai ales cele manifestate in Romania au condus la cresterea riscurilor cu care se confrunta companiile de constructii din punct de vedere financiar. Nivelul ridicat al competitiei din piata constructiilor corelat cu cheltuielile mari de capital au facut ca organizatiile de constructii sa devina din ce in ce mai vulnerabile. In aceste conditii, companiile de constructii au inceput sa accepte un numar din ce in ce mai mare de riscuri, peste puterea lor de gestionare, doar ca sa ramana in piata. Ca rezultat, acestea participa la licitatii cu preturi din ce in ce mai mici, facandu-le vulnerabile la aparitia evenimentelor neprevazute care sunt inerente oricarui proiect de constructii. Cel mai important aspect care se manifesta in actuala conjunctura politica, economica, sociala si administrativa este reprezentat insa de lipsa de lichiditati atat la nivelul autoritatii contractate, dar mai ales la nivelul contractorului, care conduce la intarzieri in derularea proiectelor, aplicarea de penalitati de intarziere si pierderea oportunitatilor, cu efect direct asupra starii de sanatate a proiectelor si a organizatiilor. Proiectele de constructii de infrastructura au la baza conditiile de contract FIDIC amendate prin conditiile speciale de autoritatile contractante. Lucrarea de fata isi propune sa analizeze efectul conditiilor de contract referitoare la relatia financiara dintre beneficiarul lucrarii si contractor, precum si influenta pe care acestea o au asupra managementului financiar exercitat de contractor, punand la dispozitia acestora un instrument practic de luare a deciziilor.

The economic changes of the last decade both globally and especially those manifested in Romania have increased the risks faced by construction companies financially. The high level of competition in the construction market correlated with higher capital expenditures made the construction organizations become increasingly vulnerable. In such conditions, construction companies have begun to accept a large number of risks beyond their power to manage, just to stay in the market. As a result, they participate in tenders with prices increasingly smaller, making them vulnerable to the occurrence of unforeseen events that are inherent in any construction project. The most important aspect construction companies’ face in the current political situation, economic, social and administrative is represent by the lack of liquidity at the level of the contracting authority, but especially at the contractor, leading to delays in the project implementation of penalties for delay and lost opportunities, with direct effect on the health status of projects and organizations. Infrastructure construction projects based on FIDIC Conditions of Contract amended by special conditions for contracting authorities. This paper aims to examine the effect of conditions of contract relating to the financial relationship between the beneficiary and the contractor work and the influence that they have on the financial management exercised by contractor, providing them a practical tool for decision-making.

 
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