Nejnavštěvovanější odborný web
pro stavebnictví a technická zařízení budov
estav.tvnový videoportál
Dřevostavby
Archiv článků od 30.1.2012 do 13.8.2012

Archiv recenzovaných článků

zpět na aktuální články

13.8.2012
doc. Ing. Bohumil Straka, CSc., Ing. Milan Šmak, Ph.D.

This paper is based on the results of theoretical, implementation and realization work of load-bearing systems for timber frame houses. The paper contains the conclusions from designing and realization of some selected structures especially of the mountain hotel which is being built in the Krkonoše Mountains (Czech Republic).

LEED 2012 zažehl ostrou debatu o certifikaci dřeva
6.8.2012
Mgr. Radomír Dohnal

Rating of LEED has clearly favored FSC certification (Forest Stewardship Council) over the other, let's say competing types of national and international certification of wood. Critics point to the FSC for example, that in principle there is no clearly identified reason for the creation of an evaluation standard.

30.7.2012
Ing. Eva Dvořáková, Ing. Anna Kuklíková, Ph.D.

The object of this work is a numerical analysis of the behavior of wood-concrete composite ceiling structure, consisting of concrete slab and wooden beams of glued laminated timber. The main objective is to explore the use of concrete slabs, which assists with wooden beams, and using models in ANSYS to investigate its behavior in the load floor construction. The accuracy of numerical analysis of wood-concrete structure fully depends on the material models. Therefore the material models will be later verified by experimental results.

30.7.2012
Ing. Roman Zoufal, doc. Ing. Petr Kuklík, CSc., prof. Ing. František Wald, CSc.

In addressing the fire safety of buildings it is necessary to know the value of fire resistance of building products and constructions of building and to design constructions, which meet required fire resistance values. It is necessary to distinguish two categories of elements: building products and construction.

23.7.2012
Ing. Kamila Horová, prof. Ing. František Wald, CSc.

Determination of the development of fire in the compartment with subsequent detection of temperature in different parts of the structure requires knowledge of many parameters. The most important step is to determine the design fire scenario that matches the extraordinary fire situation best. The design of fire can describe the temperatures in the fire department and determine the heat transfer in structure. Let's look at several models and the thermal and mechanical load of structures.

9.7.2012
doc. Ing. Roman Réh, CSc., Drevárska fakulta Technickej univerzity vo Zvolene

Development of construction industry requires the development of improved properties of various materials. Innovation material properties provide cost advantages over conventional solutions, and can also bring greater flexibility in the construction. The construction applies a wide range of traditional materials, including plywood boards.

2.7.2012
doc. Ing. Petr Kuklík, CSc., Ing. Lenka Melzerová, PhD.

The paper deals with optimizing the thickness and material of the reinforcing plates used for beams of glued laminated timber. It was first mapped in detail twenty unreinforced beams of glued laminated timber, where the great attention paid to accurately determine the elastic modulus in the direction of fibers of individual segments of blades and their localization in the beam.

25.6.2012
doc. Ing. Petr Kuklík, CSc., Ing. Aleš Tajbr

Timber trusses with punched metal plate fasteners are designed as plane structures loaded only in their plane. Actions applied perpendicularly to the truss plane must be transferred by engineered bracing system. Correct design of the bracing system is considered to be one of the essential conditions providing required reliability of the whole roof structure. The CTU in Prague, Faculty of Civil Engineering, Department of Steel and Timber Structures in cooperation with company Vazníky D.N.K. s.r.o. have performed load tests of three different types of engineered bracing truss structures. The aim of the tests was to describe behaviour of the specimen under horizontal load. Numerical model of two common types of bracing frames and a model of a whole roof consisting of 10 timber trusses was made to verify the results obtained from the experiment.

18.6.2012
Ing. Anna Kuklíková, Ph.D., Ing. Pavel Nechanický

Wooden-concrete ceilings are used especially in strengthening the existing ceilings with wooden ceiling beams. They have great potential also as precast concrete ceilings of multi-storey wooden buildings. They significantly increase the stiffness and resistance of the ceiling structure. Wood-concrete ceiling structure parameters are also better in the field of impact and airborne sound insulation and fire resistance, more than traditional wooden ceilings.

4.6.2012
Ing. Ivana Nohová, Ing. Robert Prix, prof. František Wald, ČVUT Praha

Quality of fire protection is achieved by appropriate education and training, research, investment in technical solutions and equipment of buildings, legislation, standards and work of professional and volunteer fire brigades. The Czech Republic in the European and global statistical comparisons, long been high on the success of fire protection of persons and property. The article is important summary of the options in the fire resistance design of structures in the national regulations.

21.5.2012
Akad. arch. Aleš Brotánek

Construction of straw often attracts a supporter of natural building, however we encounter a critical rejection of orthodox among builders. Post of architect Aleš Brotánek analyzes using straw in facades of wooden buildings, which seems to be questionable at present. It defends its environmental advantages, but also a convenient fire resistance of over 120 minutes due to protection (external and internal) non-flammable layers of clay and a thickness of 50 mm and lime plaster thickness of 30 mm. The application of straw is accompanied by practical examples, including installation.

21.5.2012
Ing. Jana Pexová, Ph.D., Vysoké učení technické v Brně, Fakulta stavební, Ústav pozemního stavitelství

The article is focused on the reconstruction of traditional timber joist ceilings with an additionally cast concrete slab. At Faculty of Civil Engineering in Brno conducted experimental work aimed at the analysis and behaviour of composite slab structures. Huge attention was put also on the separation of the concrete from the timber parts of the structure with the help of foils (separation layer) to prevent the movement of moisture from the concrete mixture to the timber elements. Therefore the increase in water content within the wood was also observed during the experimental part of the research together with the effects of the separating film to the characteristic of the coupled elements - coupling slip modulus K [N/mm].

arch. smola
30.4.2012
Ing. arch. Josef Smola, Ing. Martin Růžička

What is the current situation in creating legal standards in the Czech Republic, which crucially limits the design, implementation and operation of buildings in general and then specifically in the field of fire regulations that regulate the implementation possibilities of wooden buildings?

dřevěné konstrukce
9.4.2012
Ing. Jana Pexová, VUT v Brně, Fakulta stavební, Ústav pozemního stavitelství, Veveří

The article is devoted to research on the influence of the separation layer wood-concrete floor structures. Using the separation layer is justified especially in the case of reconstruction of historically valuable floor structures, such as a painted deck or beams, where water during the casting technology may cause damage, or even in the case of concrete applications with a high coefficient of water, where excessive moisture could adversely affect the mechanical properties of wood.
According to the results of the experiments we can say that in the application of concrete with a water factor approximately 0.4, it is not necessary to use concrete structure interlayer separation between concrete and formwork. Using foil separation negatively affects stress coupling elements, and thus the entire composite structure.

řezivo dřevostavby
26.3.2012
Ing. Erika Nunez, Technická univerzita ve Zvoleně

Wood that is used in building construction, requires evaluation of the properties - classification in grade with regard to its mechanical properties. Methods for assessing the quality of structural timber is divided into two groups: a visual method and automated methods based on different principles. Quality of timber is determined by the Slovak technical standards and EN. STN EN 49 1531 provides classes of timber - S0, SI and SII, as well as sorting criteria. The evaluation of quality timber ultrasonic method is classified into the timber strength class C with the corresponding values of density, elastic modulus and characteristic strength according to STN EN 338. Highest reliability and efficiency of sorting structural timber is achieved by a combination of both methods of assessing its quality.

19.3.2012
Ing. Eva Dvořáková, Ing. Anna Kuklíková, Ph.D.

It is necessary to perform fire tests of wood-concrete structures of them trying to get as much knowledge that would allow the develop computational models. This paper focuses on describing the problem of composite wood-concrete structures and an overview of new knowledge about their behaviour under fire.

dřevobetonové konstrukce
12.3.2012
Ing. Pavel Nechanický, ČVUT, České vysoké učení technické v Praze

In recent years we can observe in the Czech Republic increased interest in the buildings of wood and wood-based materials. One of the technologies by which the Czech Republic is growing interest is the designing of composite wood concrete structures. So far, they are mainly used for reinforcement and strengthening of the old roof structure. But their use may also find the construction of residential and commercial multi-storey buildings or for the design of bridges and footbridges.

lepené dřevo, struktura dřeva
5.3.2012
Ing. Jan Vaněrek, Ph.D., Ing. Anna Benešová

Adhesives used for timber are more rigid and more durable than wood, but also have much greater resistance to water. Despite this fact the way of using of different synthetic resins influences design of these members in different service classes. Phenol-formaldehyde (PF), resorcinol-formaldehyde (RF), phenol-resorcinol-formaldehyde (PRF) resins are generally used as a binder for exterior grade members production. Melamine-formaldehyde (MF) and Melamine-urea-formaldehyde resin is slightly less durable than these above. Products bonded with polyvinyl acetate (PVAc) and protein-based adhesives will not withstand prolonged exposure to water or repeated high–low moisture content cycling in bonds of high density woods. Some isocyanate, epoxy, polyurethane, and cross-linked polyvinyl acetate adhesives are durable enough to use on lower density species even under exterior conditions. This paper deals with different types of adhesive from the durability point of view by comparing strength properties, and considering the possibility of IR analyzing.

6.2.2012
Vlastimil Růžička, redakce

The city of Olomouc is the owner of an interesting low-energy building for education center Sluňákov with a focus on developing the relationship between man and nature. Construction was awarded the Grand Prix of architects in 2007.

30.1.2012
Ing. Jaroslav Vychytil, ČVUT v Praze, Fakulta stavební, katedra konstrukcí pozemních staveb

In last time popularity of wood-based structures is increasing. Most parameters in the design phase can be calculated using known procedures, but the acoustics is a problem with the theoretical determination of sound reduction index of wooden structures just, because there are the only reliable methods to determine transmission loss of silicate-based structure. In this paper is presenting the calculation method used to determine the sound reduction index of timber floor structures with visible beams.


zpět na aktuální články
 
 
Reklama