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Archiv článků od 7.5.2023 do 15.1.2024

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15.1.2024
Ing. Miroslav Urban, Ph.D., prof. Ing. Karel Kabele, CSc., doc. Dr. Ing. Zbyněk Svoboda, Ing. Ondřej Horák

Starting from January 1, 2023 (in the Czech Republic), on the basis of § 4, paragraph 1 of Decree No. 264/2020 Coll., on the energy efficiency of buildings, it is necessary for buildings or zones with cooling, humidity control or electricity production to calculate the energy efficiency of the building with an interval of one hour. The subject of the article is an approximation of the basic specifics of the hourly step of calculation and a comparison of the results of the calculation and the assessment of energy intensity in the monthly and hourly step of calculation according to the requirements of the applicable legislation.

Foto © goodluz, Fotolia.com
8.1.2024
Ing. Soňa Sopóci, CEO, Affida, s.r.o.

a. Every leader dreams of a motivated team. In this post, you will learn about the anatomy of success, why some individuals are successful, how success ties into ability, and what it truly means to possess ability, about motivation's various types, how to enhance it and provide support.
b. Každý lídr sní o motivovaném týmu. V tomto příspěvku se dozvíte o anatomii úspěchu, o tom, proč jsou někteří jedinci úspěšní, o tom, jak úspěch souvisí se schopnostmi a co to skutečně znamená mít schopnosti, o různých typech motivace, jak ji zvýšit a poskytnout podporu.

Fotometrie činitele denní osvětlenosti, doc. Ing. Jan Kaňka, Ph.D.
8.1.2024
doc. Ing. Jan Kaňka, Ph.D., Ing. Bc. Jaroslav Vychytil, Ph.D.

The article deals with the description of selected graphic-numerical methods used to determine the amount of daylight. The principle of derivation of these methods is explained and the principle of working with the relevant diagrams is described. Nowadays, we rarely see the use of diagrams in practice, but some professional software uses them either directly or at least in their graphical outputs.

Foto © lightfield studios, Fotolia.com
19.12.2023
Vladimír Baletka, eFACILITY consulting s.r.o.

This article focuses on common issues faced by owners and operators of buildings and technical equipment. Key themes include the lack of proper documentation, failure to meet legislative requirements, and frequent mistakes in safety procedures. The author thoroughly discusses various aspects, including missing documentation, insufficient authorizations and training, and non-compliance with safety standards. The article also emphasizes the importance of proper documentation management and compliance with current legislative requirements to ensure safe and efficient operation.

11.12.2023
doc. Ing. Jan Kaňka, Ph.D., člen TNK 76 Osvětlení, ČKAIT Praha

The paper deals with the uniformity of daylight in living rooms. It investigates the effect of the way the size and location of the living space in the living room is determined on the uniformity of light.

Foto © endostock, Fotolia.com
5.12.2023
Juraj Grenčík

The paper presents the concept of maintenance engineering as understood in the new European standard EN 17666:2022 Maintenance - Maintenance engineering - Requirements. The standard introduces maintenance engineering as a discipline that uses competencies, methods, techniques and tools to develop and support maintenance to ensure that (maintenance) item is able to perform its required functions in a safe, sustainable and cost-effective manner throughout its life cycle.

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13.11.2023
Ing. et Ing. Lenka Gábrová, Ph.D., Mendelova univerzita, Lesnická a dřevařská fakulta, Ústav nauky o dřevě a dřevařských technologiích

The article deals with daylighting assessment in habitable rooms according to the currently valid Czech Standard ČSN 73 0580-2 and according to the Draft Czech Decree on Requirements for Constructions. The case study investigates and compares the daylighting availability in rooms which meet the requirements stated in the draft decree.

6.11.2023
Mgr. Vitalii Komlev, prof. Ing. Josef Macháček, DrSc.

The article presents the design of prestressed cable-net glass façades based on the ANSYS software. The suggested model is validated and verified using published tests and published models in another software and used for a parametrical study of façades with point-fixed (“spider”) fittings. The study embodies two dimensions of the net, a spectrum of stainless steel Macalloy single spiral strands and laminated glass panes of various thickness. The cable prestress was taken as 30 % of their design load in accordance with published recommendations. The design respects the valid European standards for glass and loadings in serviceability and ultimate limit states. The results present tables of deflections, glass stresses and cable forces.

30.10.2023
prof. Ing. Josef Macháček, DrSc., ČVUT v Praze, Fakulta stavební

The article deals with preliminary information on design of prestressed cable-nets supporting large glass façades. Described are façade components and examples of prominent realized façades. In the survey of primary publications the trend of experimental and theoretical approaches concerning design problems of these structures is presented (securing of necessary stiffness and load capacity, danger of a glass-cable-net connection failure, failure of anchors or loss of prestressing, dynamic behaviour during failures, blasts and earthquakes, temperature effects). In more details are described publications used in the follow-up Part [31] for validation and verification of the own numerical analysis and parametric studies of these façades.

23.10.2023
Ing. et Ing. Eva Šoulová, Vysoké učení technické v Brně, Fakulta stavební, Ústav pozemního stavitelství

Textile and leather wallpapers are an integral part of the interior of historic buildings. These types of wallpaper are specific in their construction, where they are stretched on wooden frames and form a membrane in front of the wall. Verification of diffusion properties is one of the steps to elucidate the thermal-humidity behaviour of these historical structures. Knowledge of diffuse properties is important for architectural and historical surveys and for the reconstruction of historical buildings. Based on this knowledge, we can assess other properties of wallpaper construction, such as moisture and microbial climate.

22.10.2023
Ing. Jaroslav Baran, Slovenská technická univerzita v Bratislave, Stavebná fakulta

The prepared experimental program focused on the shear resistance of presstressed beams with bonded tendons needed to develop a parametric study, focused on the shear resistance of the designed beams. In the contribution, a parametric study of beam with I - cross section type DPS VP I/10 with total length of 7,0 m and a height of 0.6 m with different levels of prestress and different levels of shear reinforcement is processed. The standardized reinforcement of the cross-section used in practice is supplemented by longitudinal bars. Different design approaches were used to determine the shear resistance of the beam.

© Adobe Stock motortion
9.10.2023
Ing. Tomáš Hrádek, AVETON, s.r.o.

The standard “ČSN 73 0527 Acoustics – Acoustical design of rooms – Rooms for cultural uses – Rooms in schools – Rooms for public purposes” was revised after 18 years. In the framework of this revision, the regulations for determining the optimum reverberation time were updated, especially in relation to commonly used technologies and trends in the use of the spaces in question. A new methodology for determining the standard of acoustic treatment for spaces with lower acoustic requirements was developed and, last but not least, a code for occupancy calculations for measuring reverberation time in unoccupied spaces was defined.

1.10.2023
Ing. Matej Jurgoš, Slovenská technická univerzita v Bratislave, Stavebná fakulta. Katedra betónových konštrukcií a mostov

This paper deals with the effect of recycled aggregate in concrete beams that are subjected to flexural and shear stresses. The beams are reinforced with two types of longitudinal bearing reinforcement. The reliability factor is slightly reduced. For concrete with recycled aggregate, it is 3 % for EC2 and 5 % for prEC2. For concrete with recycled aggregate, brick aggregate it is 13 % for EC2 and 14 % for prEC2.
The reduced modulus of elasticity does not affect the results. The coefficient of variation for reinforced beams GFRP reinforcement is 6.98 % for beams with 10 mm reinforcement and 9.40 % for beams with 16 mm reinforcement. The coefficient of variation for beams reinforced with 10 mm diameter steel reinforcement is 16,79 %, and for beams reinforced with 16 mm diameter steel reinforcement is 9,87 %

28.8.2023
Ing. Vítězslav Novák, Ph.D., Ing. Šimon Baránek, doc. Ing. Jiří Zach, Ph.D., Ing. Jan Bubeník

This post discusses the possibilities of using green walls and their impact on the living environment, micro-climatic conditions and the overall perception of comfort in the interior. Green walls, or vertical gardens, are a desired architectural element of spaces, whether external or internal, for their aesthetic value and significant ability to favorably influence the environment in which we live. Vertical gardens improve acoustics, humidify, freshen and cool the air, capture dust and clean the air. The green wall also functions as a very effective heat and sound insulation system. Any larger green area fundamentally increases the quality of the microclimate, and therefore also people's lives.

26.7.2023
Ing. Jaroslav Prokop, doc. Ing. Ivan Hollý, PhD.

Modern trends in civil engineering are focused at reducing the comprehensive carbon footprint. One way to reduce a building structure's carbon footprint is to replace conventional building materials with suitable alternatives from recycled materials. These products also include recycled steel fibers from waste tires, which have a great potential for use in the form of dispersed reinforcement in concrete. Waste material from industrial production thus creates the possibility of its transformation into a recovered raw material within the so-called circular economy. This paper is focused on evaluation of the fibers in terms of geometric and mechanical properties, as well as experimental research on the properties of fresh and hardened concrete with different doses of recycled steel fibers.

tepelné ostrovy ve městech
23.7.2023
Ing. Jan Vystrčil, Ing. Ondřej Nespěšný, doc. Ing. Karel Šuhajda, Ph.D., Ing. David Bečkovský, Ph.D.

As heat islands are referred areas in urbanized cities where the temperature is significantly higher in the summer than in their surroundings. With advancing climate change, the occurrence of heat islands is more numerous. It is obvious that construction has a direct effect on the creation, or on the contrary, on the regulation of heat islands in cities. Due to the available possibilities of 3D modelling of objects and projecting with the help of the BIM method, it is possible to carry out numerical simulations of the effect of objects on the surroundings and monitor the indicators of the formation of a heat island. Building objects can therefore be designed with a high regard for the environmental aspect of the project. This paper describes selected options for numerical modelling of heat islands.

20.6.2023
Ing. Marek Petreje, doc. Ing. Michal Sněhota, Ph.D., Ing. Tomáš Chorazy, Ph.D., Mgr. Barbora Rybová, Ing. Petra Hečková, Ing. Michal Novotný

Within the project, a new concept of a combination of a constructed wetland and an extensive green roof with the use of grey water for irrigation was designed, built, and tested in experimental operation. In accordance with the principles of circular economy, a substrate for extensive green roofs with an admixture of recycled materials based on recycled demolition waste and pyrolyzed sewage sludge in the form of biochar was designed and initially experimentally tested. The hydrophysical characteristics of the proposed substrate mixtures were determined and two were selected for use on wetland-extensive green roof experimental beds. Water balance, water chemistry at the green roof runoff and vegetation condition were monitored as a function of biochar addition.

Foto ©u_kkioyol4oq- Pixabay.com
8.5.2023
Ing. Pavol Jaroš, PhD., doc. Ing. Marián Vertaľ, PhD., Ing. Richard Slávik, PhD.

In the past, natural stone was among the most used building materials in the Renaissance and Gothic periods. On the territory of the Slovak Republic, sandstone was used for its suitable properties, good compressive strength, appearance, and good machinability. Sandstones still form the supporting elements of sacral and public historical buildings. These building structures are exposed to the weather because the surface finish consists of capillary-active materials or none. From the point of view of monument protection, it is not possible to propose hydrophobic modifications and therefore water coming from driving rain can be absorbed into these structures of historical buildings. This article describes the absorption and redistribution of water in structures using one-dimensional computational simulations of liquid water transfer in selected sandstones from eastern Slovakia using a simulation tool. The results are compared with German sandstones.

Foto ©WikimediaImages- Pixabay.com
7.5.2023
Ing. Jiří Pospíšil, Ing. Jan Valentin, Ph.D., Ing. Pavla Vacková, Ph.D., Ing. Leoš Horníček, Ph.D.

In the Czech Republic, a preparation of high-speed lines construction according to principles adopted from France is currently in process. Its substructure is among others to be made of an asphalt concrete layer. Nevertheless, the requirements on asphalt mixture properties cannot simply be taken from the French standards, as a different procedure for the compaction of test specimens, which are used for mechanical and functional tests, is used in the Czech Republic. This paper presents the results of an experimental study that compares the impact of test specimen compaction methods used in the Czech Republic and in France on selected properties of asphalt concrete. As a part of the study evaluation, a mutual correlation between individual compaction methods is identified and discussed.


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