Archiv článků od 21.3.2016 do 11.12.2017

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Moderní metody pro měření osových sil v prvcích stavebních konstrukcí

Verification and in Situ Application of the Modern Method for Axial Tensile Force Measurement in Elements of Civil Engineering Structures

11.12.2017 | Ing. Tomáš Klier, Pontex Praha, odělení diagnostiky, prof. Ing. Michal Polák, CSc., ČVUT Praha, Fakulta stavební
In many practical cases it is important to know the actual value of tensile forces in prestressed elements of civil engineering structures. Main conclusions from experiments which were carried out within verification process and in situ application of the new method for an experimental estimation of the tensile force are described in the paper. The method is suitable for new structures and especially for existing ones.
© victor zastol'skiy - Fotolia.com

Differences in the Traditional and New Approach to the Daylight Evaluation of Buildings

11.12.2017 | Ing. et Ing. Lenka Gábrová, Ústav pozemního stavitelství, Vysoké učení technické v Brně, Fakulta stavební
The article deals with a comparison of a room area size which is suitable for reading and writing according to two daylight evaluation criteria. The first one is the daylight factor which is determined under the CIE overcast sky model and it is traditionally used for quantitative daylight evaluations of buildings. The second compared evaluation criterion is the daylight autonomy which is one of new daylight metrics whose calculation is based on daylight illuminance values throughout the year and for a specific location.

The Methods of the Geodetic Documentation Creation for the Objects Reconstruction

6.11.2017 | Ing. Ján Ježko, PhD., Katedra geodézie, Stavebná fakulta, STU v Bratislave
The article describes the methods of the surveying data and documentation production. The documentation is used for the process of planning, realisation and reconstruction of transport, energetic, industrial, ecologic and public objects. The documentation is also used in the remediation process and the protection of the buildings and historical objects. In these processes, it is necessary to know the spatial dimension – location data, the location of these objects on the Earth's surface and shape and dimensions of these objects. The activities that lead to the realisation, reconstruction and remediation of building objects require a quality maps, photogrammetric images and geodetic models (3D models), which are mostly realised in a suitable interactive graphic PC system in 3D digital form.
Opravy historických objektů z pozice statiky a z hlediska památkové péče

Repaits of Historic Buildings from the Position of Static Engineering and from the Point of View of Heritage Care

30.10.2017 | doc. ing. Ladislav Klusáček, CSc., doc. ing. Zdeněk Bažant, CSc., VUT FAST Brno
Heritage care specialists in the repair and reconstruction of historical buildings prefer using of previous working methods and especially materials, sometimes too strongly. It is not always easy to satisfy their requirements, with regard to the problematic of static object state. It is necessary to find suitable compromises.
Stavebně-technický průzkum brněnského kina Scala

Building Survey of Scala Cinema

16.10.2017 | doc. Ing. Pavel Schmid, Ph.D., Ing. Iva Rozsypalová, Ing. Ondřej Karel, Ing. Petr Daněk, Ph.D., Ing. Petr Žítt, VUT Brno, Ústav stavebního zkušebnictví
The paper deals with structural-technical survey of Scala cinema in Brno. It is a historic building completed in 1928. The main purpose of the diagnostic survey was passportisation of structure´s defects, determine the quality of concrete and reinforcement, assessment of defects and failures causes, evaluate the condition of the ceiling structure in relation to the considered reconstruction above cinema.
© 100ker - Fotolia.com

Structure of framework (part 1)

7.8.2017 | Ing. Jan Vinař, MURUS, monumenta renovamus, s.r.o.
The paper deals with the principles of structure, function, use, disfunction and repairs of framework (part 1 to 5).
Hydroizolace z asfaltových pásů, ilustrační foto: Petr Bohuslávek, redakce

Verification of the possibility of joining asphalt insulation belt, the results of the strength of their connections

17.7.2017 | Ing. Jindřich Sobotka, Ph.D., VUT v Brně, Fakulta stavební, Ústav pozemního stavitelství
The mutual joint waterproofing aspfalt strips can in practice be done in different ways. But not everyone is the correct one. Also important is the width of the overlapping associated strips. We will deal with strongholds in the modified stress and oxidized asphalt strip and compare the strength of the joints. If the bitumen is used as additional waterproofing is necessary, select the types of bitumen sheets with matching suitable bearing insert. As a waterproofing type we should use the modified asphalt strip. The issue of reliability of waterproofing is associated with a high quality of work performed. This quality is affected not only the human factor, but also the technology used for implementation of waterproofing layers. Another influencing factor is the type of applied asphalt waterproofing strip.

Wooden Construction of the T18 Gyms

3.7.2017 | doc. Ing. Jaroslav Sandanus, PhD., doc. Ing. Kristián Sógel, PhD., Katedra kovových a drevených konštrukcií SvF STU v Bratislave
Between 1975 and 1985, many gyms of T18 type were built in Czechoslovakia. These gyms were mostly intended for schools, specifically primary schools. The manufacturer of these structures was Bučina Zvolen. The index T18 relates to the span of the load-bearing structure which amounts to 18 meters. The ground-plan measurements are 18,8 by 41,15 m.
The gyms were designed as low-cost structures, which also affected the length of their useful life – 20 to 25 years. In the present, many of these structures are still in use even though they are over 40 years old. Since there has been no refurbishment of these structures to this day, they fail to meet any normative criteria, especially concerning the thermal protection of the structure. Due to unsystematic maintenance, defects have in many cases occurred on the load-bearing members. These can result in limits to the structure’s usage and eventually to its complete shutdown. Under some conditions, it is possible to lengthen the useful life of the gym and it should be in the interests of its owners to be able to continue using it. Based on the diagnostics performed on the specific structure in Želiezovce (Slovakia) and the data collected from other gyms of this type, the authors of the presented contribution have elaborated the static calculation of the load-bearing timber structure for the case of enhancing the heat insulation properties to meet the European standards.
Bytové domy v Praze © TZB-info

What are the common parts of residential buildings in the Czech Republic?

19.6.2017 | Ing. Petr Bohuslávek, redakce
The definition of what is a common part of a residential building is essential especially when modifying the building structures and eliminating defects that affect both a common part and residential units. How common parts are defined affects who finances the modifications and reconstructions of such structures and parts. The definition of common parts is based on the new Civil Code (No. 89/2012 Coll.) and on the already abolished Act on Ownership of Housing (No. 72/1994 Coll.).

Thermal-technical evaluation of inner wall cavities within framework of a suggestion of wet masonry rehabilitation

22.5.2017 | doc. Ing. Jaroslav Solař, Ph.D., VŠB TU Ostrava
For excessive wet masonry rehabilitation, except for other methods, the method of air cavities is used. These can be wall or floor cavities. The wall cavities may be situated either on the internal or the external side of the wall. From the height point of view, internal side cavities can be located under the floor or above the floor level. This contribution only deals with the cavities above the floor level. In the projection practice, the air cavities usually are designed only empirically. But it is necessary to carry out their thermal-technical evaluation for their correct capacity. The matter of the evaluation is the topic of the following contribution.
2 comments, last 29.08.2017 08:03

The Effect of Local Thermal Bridges on Thermal Performance of Curtain Walling

17.4.2017 | Ing. Roman Jirák, Ph.D., Ing. Petr Jaroš, Ph.D., DECOEN znalecký ústav s.r.o.
U-value calculation of curtain walling is one from more difficult calculation in the civil engineering. In according to trend of increasing glassing surface of building envelope, the curtain walling has big influence on thermal behaver of buildings. This is why it is necessary to calculate the thermal insulation properties with special attention. This article focuses on influence of different local thermal bridges on curtain walling U-value.

Energy performance of industrial buildings – PART 1 – LEGISLATION

10.4.2017 | Ing. Jiří Cihlář, CEVRE Consultants s.r.o.
Energy efficiency of industrial buildings in not very common topic. However, the quality of design must be based on valid national legislation and technical standards. Task to achieve best energy ratings is more and more frequently laid on building designer and energy specialist directly from investor – developer.

The invention, patent or utility model - who should sort?

8.3.2017 | Ing. Zdeněk Lyčka
The article explains the differences between the invention patents and utility model from the perspective of Czech legislation. Also highlights the confusion individual categories and purposeful fraud by producers and sellers of equipment.
1 comment, 08.03.2017 07:44

Diffusion Properties of Surface Rehabilitation Mortars

6.3.2017 | Ing. Šárka Nenadálová, Ing. Lukáš Balík, Ph.D., Ing. Milan Rydval, Ing. Tomáš Bittner, Kloknerův ústav ČVUT v Praze
Water vapour permeability is one of significant material properties. The value of water vapour resistance factor is necessary to know to be able to rehabilitate structures, mainly after floods. One thing is essential – to know what are the values of water vapour resistance factor of the used material to know how long the structure will take to be dried and users can come back to live there.

Sound attenuation of a wall with finite length

20.2.2017 | doc. Ing. Jan Kaňka, Ph.D., Stavební fakulta ČVUT Praha
This article continues the discussion [4] from 2010. The wave theory light and of its diffraction was substantiated by French physicist Augustin-Jean Fresnel (l788–1827). Soon we will recall the bicentennial of his discovery. In 1819 Fresnel received Prize of the French Academy of Sciences for discussion of wave diffraction. Wave attenuation is caused by interference. Laws of wave diffraction also apply to the sound. According to them two-dimensional problem i.e. the sound attenuation of a wall with finite length can be solved.

Reducing of Noise from Sources of Heat and Propagation of Sound

9.1.2017 | Ing. Miroslav Kučera, Ph.D., ČVUT v Praze, Fakulta strojní, Ústav techniky prostředí, Časopis Vytápění, větrání, instalace
The paper presents an example of solving the propagation of noise from an air/water heat pump installed in the basement of an apartment building. Air intake and exhaust are brought out on the façade of the building, where it is calculated the noise situation in the protected exterior of the building. In the interior it is solved the propagation of sound from the plant room to the protected interior space. In conclusion, the results are compared with the data from the report on measurement at the realized work.

Commentary to revision of the government regulation on health protection against negative effects of noise and vibrations

12.9.2016 | Ing. Pavel Rubáš, Ph.D., Technický a zkušební ústav stavební Praha, s. p.
The values of equivalent sound pressure level and maximum sound pressure level are used in the government regulation on health protection against negative effects of noise and vibration as criteria for expressing noise limits. These limits are applied with regard to negative effects of noise in-situ and workplaces The Czech government approved on 15. 6. 2016 the revision of Decree no. 272/2011 Coll. This amendment includes relevant changes of the on the public health protection law that is valid from 1. 12. 2015.

Water vapor permeability of wood according to the density of the material

25.7.2016 | Ing. Jakub Šlik, Ing. et Ing. Richard Hlaváč, ČVUT v Praze, Fakulta stavební, Katedra konstrukcí pozemních staveb
This thesis deals with the water vapor permeability of wood for the most commonly used types of wood for construction work - Norway spruce (Picea Abies). Diffusion of water vapor is solved according to the density of the material, which varies depending on climatic conditions tree growth. These different conditions are in the Czech Republic mainly characterized by different altitude growing zones. Water vapor permeability is solved in the thesis by a method of measuring the diffusion resistance of materials. Specifically, the method of wet cup and dry cup, which is carried out using EN ISO 12572 knowledge and advices of previous researchers of that method. The results were compared with values reported in the Czech standard and later used for construction project of the typical timbered buildings with respect to contemporary legislation.
1 comment, 25.07.2016 07:31

Extended Sharp’s Method for the Calculation of the Airborne Sound Insulation of Building Structures

11.7.2016 | Ing. Jan Šlechta, Ph.D., ČVUT v Praze, Univerzitní centrum energeticky efektivních budov (UCEEB)
The airborne sound insulation of building structures is a subject of permanent interest of designing engineers and architects. Although the weighted apparent sound reduction index is in the final phase verified by measurements in already established buildings, semi-empirical methods have a potential of non-negligible financial savings in the building design phase. The paper presents a set of equations convenient for the calculation of the airborne sound insulation of single and double building structures which extends the Sharp’s method. The equations are derived by mathematical procedures but the purpose of this paper is to supply the reader with a prepared computational tool and that’s why the derivation is listed in different publications. The set of equations is compared with laboratory measurements and other methods both for single (EN 12354-1, Davy’s and Watters’ method) and double structures (Davy’s and Watters’ method).

Eurocode 5 – Design examples

21.3.2016 | Ing. Bohumil Koželouh, CSc., soudní znalec
Examples 9 to 15. Preface and helping data for calculation see Part 1 to 3.
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