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Archiv článků od 4.5.2015 do 27.7.2015

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27.7.2015
Ing. Václav Ráček, doc. Ing. Jan Vodička, CSc., doc. Ing. Jiří Krátký, CSc.

Utilization of steel fibre reinforced concrete (SFRC) during the design of load-bearing structures presupposes that manufactured SFRC will be classified into the strength classes. For static design, these stated strength in the strength class are necessary: compression, tension when the macrocracks open and agreed limit deflection during the bending test on beams. The paper shows the procedure of determining the strength class of SFRC under such prescriptions. Different arrangement of the test equipment, differences in the ranges of test beams and their modifications affects the procedure for evaluation of tensile strength, including those resulting strength classes. Compressive strength of SFRC is considered in accordance with the evaluation of common (normal) concrete (cylinder/cube). These strength classes, calculated by two methodologies, show the difference in classification of one type of SFRC, in this case by increasing strength of SFRC after formation of the macrocrack caused by higher concentrate of fibres.

20.7.2015
Ing. Jindřich Stodůlka, Ing. Tomáš Petříček, Ph.D., Ing. Markéta Bogárová, Ing. Jan Plachý, Ph.D.

Stabilization of roof waterproofing coating, which uses the technology of mechanical fixing, are among the most commonly used technology not only in the Czech Republic. With an increasing number of roofs which are realized in practice still appear defects in these types of roofs, which are often caused by failure of the fasteners.
The aim of this paper is introduce the reader to the results of experimental measurements and make the statistical analysis of resistance of chosen fasteners supplied to the Czech market, find the possible cause of the failure of mechanically fastened roofs and evaluate the potential impacts on the design of mechanically fastened system.

6.7.2015
doc. Ing. Václav Kupilík, CSc., ČVUT Praha

According to the statistics of the Fire Rescue Service of the Czech Republic, fires in apartment houses are among the most frequent tragedies. Therefore, it is necessary to pay them due attention. Their cause is often the incorrect execution of building construction disrespecting fire safety aspects.

6.7.2015
Ing. Jozef Bednar, PhD., Dr. Martin Teibinger, Dr. Julia Bachinger, Dipl. Ing. Irmgard Matzinger

The present study reveals the influence of typical wind permeability of connections at the eaves on thermal losses. Therefore, a laboratory test and a field test with different insulation materials and different typical geometries of the gap at the eaves were carried out. In order to show the influence on the heat flow rate dependent on insulation material characteristics, three insulations with different densities and air flow resistances were chosen. Furthermore, in the laboratory test the roof inclination, the insulation thickness and the fixation of the roofing underlayment were varied.for the laboratory test, a part of a roof was constructed in the climate chamber. Hence, an influence on the heat flow rate depending on the insulation material has been detected. Where as cellulose insulation and the heavy mineral wool show no significant reaction of the heat flow under different wind velocities and different gap sizes, the investigated lightweight mineral wool insulation shows an important variation of the Uvalue. For the field test, a typically pitched roof was constructed, the eaves placed in the main direction of the wind. It was shown, that the influence of wind on the heat flow rate is negligible if the gaps at the eaves are masked by a projecting roof. The outcome of the research project will lead to a modification of a national construction standard.

29.6.2015
Ing. Pavel Fridrich, Ústav pozemního stavitelství, VUT v Brně

The increased moisture of the building materials causes the change of its mechanical and physical characteristic. In particular the high amount of loose water in construction is harmful to human beings, increase the economic expenses of usage of the building and shorten the lifetime of the building. One of the direct techniques to restore damp proofing and to increase the utility value of the building that have undergone rapid progress in last few years is the injection procedure.With use of experimental methods in my work I deal with evaluation of two injection compounds used in Czech Republic and with its impact on the mechanical characteristics of the mortar.

22.6.2015
Ing. Andrea Nasswettrová, Ph.D., Ing. Pavel Šmíra, Ph.D., Ing. et Ing. Soňa Křivánková

The paper presents the Acoustic Pack device which can record sound emitted by wood-destroying insect larvae while eating wood mass. It records the sound with up to eight sensors at once in several-hour records using high quality acoustic signal recording system. While detecting, it is also possible to hear an activity on a certain element in the structure. This makes it possible to obtain a complete view of the condition of elements with a graphic output of the activity and sound records. Thanks to these advantages, the acoustic system has become a great helper in the detection of damage and in the status analysis of attacked elements in the structure.

22.6.2015
prof. Ing. Jan Tywoniak, CSc., Ing. Antonín Lupíšek, Ph.D., Ing. Julie Hodková, Ing. Michal Bureš, Ing. Martin Volf

This paper describes an own development of a curtain wall panel system. The leading idea of the project was to prepare an alternative solution for replacement of old metallic curtain walls during the refurbishment of nonresidential buildings from the 1960ies – 1970ies. Presented solution use wood and wood based materials (laminated veneer lumbers) for construction of panels, with clear preference to non-oil based materials for thermal insulation. System allows for different type of external cladding (cement based boards, wooden claddings, integrated PV, support for greenery). Integration of other technical components, like venetian blinds, decentralized ventilation units, is possible. Thermal performance, noise protection and fire safety of this new envelope together with environmental oriented assessments are discussed.

15.6.2015
Ing. Aleš Vodička, Ing. Pavel Mlejnek, Ph.D, Ing. Jan Včelák, Ph.D., Ing. Petr Ptáček, Ph.D., doc. Ing. Petr Kuklík, CSc.

The article describes one of the key factors affecting the lifetime of a wooden building – moisture. It shows the most common causes and effects of increased moisture inside a wooden construction. Methods of determining moisture level in it are listed and particular one suitable for continual monitoring is presented. The suitable method is measuring of the resistance and conversion to a moisture level. Corrections of the moisture level for temperature effects and wood type are included.

15.6.2015
Ing. arch. Simona Švecová, doc. Ing. arch. Ivan Vorel, CSc.

The Czech landscape is predominantly a cultural landscape changed for the centuries. It is the cultural heritage connected with the landscape framework – with the terrain relief, water areas, rivers and vegetation. The absence of restriction of the building activities and changes in the use of the territory might cause decline of the historical cultural landscape values and disruption of the landscape cultural identity. The formulation of the cultural landscape value and the method of treatment with it are embodied in the European Convention on the Landscape, in the Preservation of Monuments Act and in the tools of territorial planning. It particularly concerns the designation of the landscape parts as the landscape monument zones, which brings possibilities of the concentrated cultural values protection. It also brings valuable information on the principles of protection for designers and investors. The preservation of the landscape values is embodied in the territorial planning tools. It concerns the principles of territorial development, where the goal characteristics of the landscape are defined; further it concerns the territorial analytic documents of municipalities and a conception of the landscape arrangement in the territorial plans.

8.6.2015
Ing. František Stránský

In buildings registered in preservation zones the preservationists require keeping of the division and shaping of the opening pane girts and respecting of the original look of the facade. Keeping the girt profile, it is nowdays permitted to glaze the window wings using insulation glass. The manufacturers of windows still make many mistakes affecting not only physical characteristics of the opening panes but also their durability – life time.

1.6.2015
Dipl.-Wirtsch.-Ing. (FH) Ondřej Flanderka, Prof. Dr.-Ing. Jörn Krimmling, Ing. Martin Vonka, Ph.D.

In 2013, the World-Green-Building Council (WGBC) made a study to address the influence of sustainable buildings on the international real estate market. In the study, it was revealed that in comparison to normally-built buildings, sustainable buildings

  • have a higher selling value
  • are rented at a higher price
  • can be used more widely.

There are certification systems used to evaluate quality and sustainability of buildings. Besides already renowned systems, e.g. BREEAM and LEED, others have started gaining popularity, for instance DGNB (Deutsche Gesellschaft für Nachhaltiges Bauen) and BNB (Bewertungssystem Nachhaltiges Bauen) in Germany. In the Czech Republic, SBToolCZ (Sustainable Building Tool CZ) was introduced by the Faculty of Civil Engineering of Czech Technical University in Prague in 2010. As part of this study, created on the basis of cooperation between Hochschule Zittau/Görlitz and Czech Technical University in Prague, the BNB (partially similar to the DGNB system) and SBToolCZ systems were compared on an office building.

1.6.2015
Ing. Roman Jirák, Ph.D., DECOEN znalecký ústav s.r.o.

The surface temperature as one of the most watched parametres of the opening panes and light enveopes not only in the Czech Republic is being assessed in a view of risk of water vapour condensation, or more precisely in a view of their health and a hygyenic flaws and ecologically sound environment where inbuilt. The mening is determination if the structure is suitable for the marginal conditions or whether is necessary to choose another structure.

25.5.2015
Ing. et Ing. Jan Dvořák, VUT v Brně, Fakulta stavební, Ústav technologie, mechanizace a řízení staveb

This article deals with the assessment of applicability of OSB boards as the main airtightening layer. Different material thicknesses and various kinds of surface modifications of boards were tested. Measurements were performed with blower-door test in an airtight chamber, which is located in the experimental wooden structure EXDR 1. The article describes a procedure of the experiment and its results.

18.5.2015
Ing. Václav Ráček, doc. Ing. Jan Vodička, CSc.

The paper presents the basic characteristics of fiber reinforced concrete (FRC) that affect its durability and allow to increase service design life of load bearing construction from FRC. This effect is in more detail demonstrated on the test results of the test samples, i.e. strength characteristics, obtained homogeneity and carbonation. The paper focuses on the SFRC, i.e. FRC when using metallic fibres.

18.5.2015
Ing. Pavel Rydlo, manažer technické podpory společnosti Saint-Gobain Construction Products CZ, divize Isover

Grey form of an expanded polystyrene (EPS) insulation have been used in the Czech Republic since 2005. It is necessary to respect application differences in between grey and white form of EPS. It´s not EPS such as EPS, in this case.

18.5.2015
Ing. Roman Jirák, Ph.D., DECOEN znalecký ústav s.r.o.

The surface temperature as one of the most watched parametres of the opening panes and light enveopes not only in the Czech Republic is being assessed in a view of risk of water vapour condensation, or more precisely in a view of their health and a hygyenic flaws and ecologically sound environment where inbuilt. The mening is determination if the structure is suitable for the marginal conditions or whether is necessary to choose another structure.

11.5.2015
Ing. Petr Pohl, projektant pozemních staveb a rozpočtář, jednatel stavební a obchodní firmy

In the article, I would like to draw attention to the issue with an outside window lintel on existing double glazed windows. The lintel is mounted below the other lintel and can therefore when replacing windows in modern window to form a problem. The article presents possible solutions window lintel. The most appropriate way is a solution that includes the total renovation of the building envelope with the replacement of windows.

11.5.2015
doc. Ing. Tomáš Matuška, Ph.D., Ing. Miloš Lain, Ph.D., doc. Ing. Vladimír Zmrhal, Ph.D.

Paper introduces the energy study for old building retrofit for future Centre of Low Energy Buildings in Pisek. Design of the energy efficient buildings with nonuniform user structure (combined residential, administration and technology use) requires the detailed dynamic simulations of buildings and energy system to develop the optimum concept meeting the comfort demand on one side and energy efficiency on the other side with minimized investment costs. Energy study of building retrofit for the Centre has shown how important could be knowledge on future building use in the design stage and has clarified the questionable issues for further design process (high fraction of fan power on electricity demand, suitable extent of PVT collectors use, optimum storage capacity for heat and cold and its cost benefit).

4.5.2015
Ing. Pavel Šmíra, Ph.D., Ing. Andrea Nasswettrová, Ph.D., Ing. et Ing. Soňa Křivánková

The article presents a technological procedure and possibilities for surface treatment of different materials by using compact parts of CO2dry ice. A purifying medium is accelerated in the nozzle of the SDI Select 60 device by compressed air stream to a supersonic speed, and so it reaches high kinetic energy. The impact of CO2 at the temperature −78.8 °C rapidly cools down the surface; dirtiness becomes brittle and loses its base adhesion, causing temperature shock. Simultaneously with this temperature effect, dry ice intensively sublimates, increases its volume and removes, at high inner tension, the impaired surface of dirtiness without any formation of abrasion waste. The device is applicable to the removal of contamination from elements which cannot be saturated with water or when it is necessary to modify elements with no need to dismantle them. The report introduces the technology when removing contamination on the surface of wooden construction elements, artefacts and stone statues, as well as when forming a relief on the native wooden surface and at a surface treatment before the application of paint, or fungicidal and insecticidal agents.


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