Archiv článků od 11.9.2017 do 12.3.2018

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Resistance of refractories against acidic environment

12.3.2018 | Ing. Daniel Mátl, Ing. Lenka Nevřivová, Ph.D., Ústav technologie stavebních hmot a dílců, Fakulta stavební, Vysoké učení technické v Brně
There are applications of refractory concretes for places where these are exposed to corrosive environments. This text deals with both description the corrosive effects and methodology of their testing. One of the most important properties of materials, affecting the chemical corrosion resistance, is their density. The second part of this text is focused on testing the refractory concretes which are currently used for applications. The aggregates were tested for the resistance to sulfuric acid.

Change of Diffusion Coefficient and Capillarity of Fibreconcrete with Concrete Recyclate in Aggresive Environment of CO2

5.3.2018 | doc. Ing. Michal Stehlík, Ph.D., Ústav stavebního zkušebnictví, Fakulta stavební, Vysoké učení technické v Brně
Adding structural fibres into concrete has an impact, both positive and negative, on the long-term durability of concrete. Polymer fibres do not resist shrinkage of the concrete, steel fibres, on the other hand, create a tough skeleton preventing deformation. Porous structure of fibre concretes exposed for a long time in the environment of CO2 is estimated using the method of determining the coefficient of diffusion resistence and the method of determining the capillary hight. Comparison of measured capillary hight and diffusion coefficient of fibreconcrete samples bring the knowledge, that close correlation between both quantities does not exist, due to the physical difference between determination of both quantities.

Detail of the chimney system passing through the combustible roof and ceiling structure

26.2.2018 | Ing. Zuzana Lacová, doc. Ing. Juraj Olbřímek, PhD., STU Stavebná fakulta, Bratislava, Slovenská republika
The detail of the chimney system passage is one of the possible details, from a fire point of view, that occurred due to the installation of new chimney systems in to the construction of the building. The chimney system passing through the combustible structure is one of the most dangerous details in the building, from a fire safety point of view, and as practice shows, is often very underestimated. An appropriate solution for the chimney passage requires the knowledge and correct design, as well as the realization and consequently correct use of the thermal appliance and the chimney system. The article deals with passage according to the requirements of the national standards for fire segments and design according to STN EN for chimneys.

Influence of Time Factor on Resistance and Serviceability of the Damaged and Subsequently Strengtened by Concrete Elements of Rugged Section

26.2.2018 | Ing. Martin Križma, PhD., Ústav stavebníctva a arcitektúry (ÚSTARCH SAV) Bratislava, doc. Ing. Ľubomír Bolha, PhD., Slovenska technická univerzita (STU) Bratislava, doc. Ing. Martin Moravčík, PhD., Žilinská univerzita, Stavebná fakulta, katedra stavebných konštrukcií a mostov, Mgr. Matúš Holúbek, PhD., Slovenská akadémia vied, Ústav stavebníctva a architektúry SAV Bratislava
With strengthening of damaged concrete linear elements have been engaged since 2003. It is a co – ÚSTARCH SAS Bratislava, FCE University of Zilina, STU Bratislava. Repaired the damaged components – new the coupling plate with reinforced contact, the coupling plate without reinforcement – replacing the geometrical condition of contact. The use of GFRP panels. The effect of the time factor on both the MS.

Beech wood for building structures assessment

19.2.2018 | Ing. Ondrej Bajza, doc. Ing. Alena Rohanová, Katedra drevených stavieb, Drevárska fakulta, Technická univerzita vo Zvolene
The text describes why and under what conditions the use of beech wood in building structures. Given the legislative and experimental requirements for verification of properties of beech sorting into classes of forts "D". Evaluation of the quality beech wood over the strength of the reliable design, production technology class predictive level as well as the durability of wooden building elements.
© M. Schuppich -

Physical and Mechanical Properties of Timber at Various Moisture

29.1.2018 | Ing. Věra Heřmánková, Ph.D., Ing. Ondřej Anton, Ph.D., Ing. Tereza Komárková, VUT Brno, Fakulta stavební, Ústav stavebního zkušebnictví
Article deals with finding of physical and mechanical properties of timber at various moisture and it also verifies addictions of single properties on moisture content of timber. In experimental part of this thesis, the density, the dimensional and volumetric swelling and the compressive strength parallel to fibre will be determined on test samples. After evaluating all the tests, the graphs of these parameters depend on various samples of wood moisture determined by weight will be created.

Study of tobermorite formation in dependence on use of various siliceous compontents

15.1.2018 | Ing. Vít Černý, Ph.D., Ing. Ján Fleischhacker, prof. ing. Rostislav Drochytka, CSc., MBA, VUT FAST Brno
Tobermorite is the main mineral compound of AAC. It increases its mechanical properties. There needs to be done research of influence of type of silica components on the mineralogical compound of AAC. In the presence study, we examine the usage of nature and artificial silicious materials. Closure of the study will be design of the optimal raw material composition, also hydrothermal treatment of autoclaved aerated concrete.
Stavba stanice metra na Náměstí Republiky

History of the use fly ash for concrete production in the Czech Republic

25.12.2017 | Ing. Tomáš Moravec, STACHEMA CZ s.r.o.
The article describes the beginnings of the use of the fly ash mixture for the production of concrete in the Czech Republic, its application on important buildings (Prague subway, Nuclear power plant Temelín) and impacts on the production technology.
Složitá rekonstrukce staršího bytového domu

Complicated Reconstruction of an Older Multi-family House

18.12.2017 | Ing. Jan Koláček, Ph.D., Ústav betonových a zděných konstrukcí, FAST VUT v Brně, doc. Ing. Zdeněk Bažant, CSc., Ústav betonových a zděných konstrukcí, FAST VUT v Brně,
In December of year 2016 has been finished the extensive reconstruction of the multi-family house built in the thirties of last century, located in the district Žabovřesky of the city Brno. Investor with architect desired the modern appearance of interior and facade of the house, which involved a number of difficult renovations and new structures that had to be consulted with structure engineer. The significant steps of the reconstruction of the multi-family house are described in detail in this contribution.
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.
Možnosti aplikace a testování systému nerezových helikálních výztužích

Application and Testing Possibilities of a Stainless Steel Helical Reinforcement for the Concrete Structures Sanation

20.11.2017 | Ing. Ondřej Karel, VUT FAST Brno, Ing. Jiří Kubanek, Saron statika Brno, Ing. Iva Rozsypalová, doc. Ing. Pavel Schmid, Ph.D., VUT Brno, Ústav stavebního zkušebnictví
The article deals with application of stainless steel helical reinforcement to sanitation of concrete structures and its application suitability focused on possible ways of diagnostics. Examples of possible use of this reinforcement are summed up.
Analýza trvanlivosti preimyselných komínov © Imperium Obrazu -

Analysis of the Durability of Industrial Chimneys

13.11.2017 | prof. Ing. Juraj Bilčík, PhD., Ing. Ivan Hollý, PhD., Ing. Natália Gažovičová, Stavebná fakulta STU Bratislava
Industrial chimneys are civil engineering works, which in addition to static and dynamic effects, direct and indirect loads, are also exposed to significant non-stationary environmental loads. Analysis of their durability focuses on the evaluation of vertical cracks, corrosion of concrete and reinforcement, which have a decisive influence on the resistance of the chimney's shaft with regard to the ultimate and serviceability limit states, as well as their durability.

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.
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.
Šetrné diagnostické metody pro hodnocení bezpečnosti dřevěných konstrukcí

Safety assessment of historic timber structures using testing of very small specimens

16.10.2017 | Ing. Michal Kloiber, prof. Ing. Miloš Drdácký, DrSc., dr. h., Ústav teoretické a aplikované mechaniky AV ČR, Centrum excelence Telč
The paper discusses approaches to safety assessment of historic timber structures using testing of very small specimens extracted from a historic structure or by direct in-situ testing. The presented methods must to take into account conditions given by the EN 16085. They further consider environmental influences and correlations of characteristics achieved by various SDTs.
Rekonstrukce dřevěných trámových stropů

Reconstruction of wooden joist ceilings

9.10.2017 | Ing. Zdeněk Vejpustek, Ph.D., doc. Ing. Bohumil Straka, CSc.
The paper shows reasons for carrying out restoration of historic wooden ceiling using “dry method” – interaction between historic wooden beams and wood-based panels. This article summarizes the process of reconstruction of historic wooden ceilings, describes the problems to be addressed and it summarizes experience with completed ceilings in Brno,Czech Republic.
Nanomateriály a vybrané oblasti ich využitia

Nanomaterials and selected areas of their utilization

2.10.2017 | doc. Ing. Ivan Kubovský, PhD., Technická univerzita vo Zvolene, Drevárska fakulta, Katedra fyziky, elektrotechniky a aplikovanej mechaniky, Ing. Miroslav Gašparík, PhD., Česká zemědelská univerzita v Praze, Fakulta lesnická a dřevařská, Katedra základního zpracování dřeva, prof. RNDr. František Kačík, PhD., Technická univerzita vo Zvolene, Drevárska fakulta, Katedra chémie a chemických technológií
The possibilities of using nanomaterials are quite broad – from increasing the hydrophobicity and photostability of surfaces, through improving the mechanical properties of traditional materials, aiding in the diagnosis and therapy of certain diseases, repairing damaged parts of the tissue, and solving problems in decontamination of the environment. Intensive research also takes place in their applications to increase the resistance of wood to wood-boring fungi and wood-destroying insects. Nanomaterials, including nanocellulose, are perspective in the field of wood fire protection, which may be important in the evolving trend of wood building construction.
Otázky sanací betonových konstrukcí parkovacích a garážových objektů

Questions of Rehabilitation a Concrete Construction of Parking Buildings

2.10.2017 | Ing. Vítězslav Vacek, CSc., doc. ing. Jiří Kolísko, Ph.D., ČVUT Praha. Kloknerův ústav
The article deals with the possibilities of rehabilitation of concrete structures the technical and technological aspects in relation to the detected condition, execute, operate and its age.
Kompozitní výztuž do betonu

Concrete and reinforced concrete

18.9.2017 | Ing. Miroslav Procházka, Technický a zkušební ústav stavební Praha, s.p.
The composite materials for strengthening/reinforcement a concrete has become the new construction product set up for compulsory verification pursuant to Act No. 22/1997 Coll. (č. 22/1997 Sb.) as amended by Government Ordinance No. 163/2002 Coll. (č. 163/2002 Sb.) as amended by Government Decree No. 312/2005 Coll. and No. 215/2016 Coll (č. 312/2005 Sb. a č. 215/2016 Sb.) This reinforcement exists in several different types, and accordingly, it also has significantly different properties which must be strictly respected in its use.
Průkazné stanovení vyztužení železobetonové konstrukce a vhodné NDT metody

Proving Non-compliance with the Prescribed Position of Steel Reinforcement in Reinforced Concrete Structures

11.9.2017 | Ing. Ondřej Anton, Ph.D., Ing. Věra Heřmánková, Ph.D., VUT FAST Brno
Despite efforts to maintain quality during the construction of reinforced concrete structures, it is relatively common for improper reinforcement to be used contradicting the project, which can lead to serious structural defects. It is then up to non-destructive testing methods to prove these defects. The key is to choose the appropriate method and device for the task.
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