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Archiv článků od 21.7.2014 do 2.2.2015

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2.2.2015
prof. Ing. Rudolf Hela, CSc., FAST VUT Brno

Many various physical, mechanical and deformation properties have to be designed, tested and observed during life of concrete because of possible failures in given service load and climatic conditions. Apart from basic strength characteristics, it is necessary to keep in view water tightness, capillarity, water absorbing capacity, frost resistance, volumetric changes or thermal expansion. Preventing of these failures during the whole life of concrete structures in various exposure classes is the basic condition of achieving required long-term durability. The text below describes several important properties of concrete connected with flaws and failures.
The crucial mechanical properties of concrete are compressive strength, splitting tensile strength, tensile strength, tensile bending strength and shear strength. Deformation properties are connected with volumetric changes and action of external and internal strength; the characteristic mechanical property is defined by static or dynamic elasticity modulus. As regards durability of concrete, the concept is relative and limited depending on the time of action of physical and chemical influences. Corrosion of concrete is the process leading to disintegration of the material by means of chemical processes or physical influences. Durability also includes fire resistance, frost resistance and abrasive quality of concrete.

15.12.2014
Ing.arch. Ondřej Pleštil

This paper deals with the reconstruction of the historical building of the cinema “Varšava” in Liberec, Czech Republic. The building designed and built in the 1920s by the german Liberec architects Effenberger and Noppes is both valuable architectural and constructional monument. However, it has suffered from faulty partial reconstructions done during the 20th century and during 8 years of closure of the building in 2008. For salvation of the building, a a new civic association “Save kino Varšava” was established in 2012. Now, it tries to halt further decay of the valuable monument at start a process which would convert the old cinema to a modern multifuctional hall of the 21th century in the future. Recently, the foyer is reconstructed and minor reconstructions in the hall are taking place. This paper deals mostly with restoration of the original ventilation system and dry rot fungus treatment.

8.12.2014
Ing. arch. Marek Janatka, Ph.D., Katedra urbanismu a územního plánování Fakulta stavební ČVUT v Praze

Prague building regulations currently represent debated and controversial topic among both professionals and the public. This is a new concept of law to which they are greatly implemented basic knowledge of urban theory and practice. The article summarizes the basic principles of the new regulation in the field of building requirements.

8.12.2014
Ing. Jan Ficenec, Ph.D., Ing. Roman Cupal, Dr. Ing. Leoš Červenka

Loggias and balconies are external structures designed for recreation and other activities, which increase the value and the surface of the property. They are positioned as part of the cladding of the building. Actually, these structures are perhaps the most exposed components of a building's cladding, and for this reason, the most degraded. This is why the repairing of these structures should certainly be included in any comprehensive renovation of a building, even though it might not have any financial effect for the owners and tenants, unlike, for example, changing fillings or additional insulation.

1.12.2014
Ing. Lenka Sirochmanová, Bc. Marianna Tomková

Construction waste is a by-product of any construction activity. This needs to be stored somewhere, some way evaluate, respectively. Further construction technology to recycle. Building construction is the engine of the economy of any country. It satisfies demand for basic human needs, adapting to production environmental, economic, technical and design conditions demand. It is a sector in which we can most see the development of science and technically, the progress of modern technologies and building materials. Despite the progress and modernization construction, however, construction industry is still environmentally harmful through production of building materials and products (energy consumption in mining and manufacturing), traffic intensity (weight and intensity of transported material), site (noise, dust, debris) and long-term use of buildings. The theme of waste management is still very actual. This paper among other things provides case studies from different areas of construction with the different method of waste management on construction site. The aim is to detect the most common form of waste management on construction site.

24.11.2014
doc. Ing. Hana Gattermayerová, CSc.

Railings are a safety feature in buildings. They should prevent the fall of people. Their requirements are not only architectural and aesthetic, but also of mechanical resistance and stability. The current designs for the construction of railings include their anchoring to adjacent structures, which have the same requirements as the very structure of the railings. The tests on heat pumps are connected to an article on the tests of solar collectors. The basic operating principles of a heat pump is that it gathers heat from the surrounding environment and then transfers it to a higher temperature level and supplies to according the whether it will be used for heating or hot water. The advantage over collectors is that it works even if the sun is not shining.

3.11.2014
Ing. Róbert Sonnenschein, prof. Ing. Juraj Bilčík, PhD.

Underground spaces in buildings are now often designed and executed as watertight concrete structures. The paper presents selected requirements and concepts for design and execution of “white tanks”.

27.10.2014
Ing. Radovan Nečes, RNDr. Theodor Staněk, Ph.D., Mgr. Miroslav Hroza

The industrial waste materials arise during the rocks mining and treating. No suitable utilization was found for it yet. These materials are stored in pond now. The aim of this work was developing low-energy hydraulic binders using these waste materials as raw component.

27.10.2014
Ing. Bohumil Koželouh, CSc., soudní znalec

Described as the greenest commercial building in the world, the Bullitt Center in Seattle, Washington pushes the envelope in urban sustainability. The six-story, 52,000-square-foot structure is designed to meet stringent requirements of the Living Building Challenge (LBC)—using photovoltaic cells to generate enough electricity to sustain the needs of its tenants, recycling its own water and waste, and reducing energy use by more than 80 percent compared to an average office building.
LBC requirements stipulated that the Bullitt Center meet a number of criteria, including responsible site selection, 100 percent on-site renewable energy generation, 100 percent of water needs provided by harvested rainwater, and on-site waste management.
The aim is to lower CO2 emissions and reduce the environmental footprint of the building. Target life cycle 250-year is a key part of that goal.

Praha
20.10.2014
Ing. arch. Marek Janatka, Ph.D., Katedra urbanismu a územního plánování Fakulta stavební ČVUT v Praze

Prague building regulations currently represent debated and controversial topic among both professionals and the public. This is a new concept of law to which they are greatly implemented basic knowledge of urban theory and practice. The article summarizes the basic principles of the new regulation in the field of territorial requirements.

13.10.2014
doc. Ing. Jaroslav Sandanus, PhD., Ing. Orsolya Katona

In the last few years the engineered building product cross laminated timber (CLT) has become very common in timber engineering applications. CLT is a cost-competitive wood-based solution that complements the existing light and heavy-frame options, and is a suitable substitute for some applications which currently use concrete, masonry and steel. This contribution deals with the analysis and design of CLT, used as floor elements. Different calculation procedures for plates loaded out-of-plane are discussed.

13.10.2014
Ing. Pavel Leber, Ing. Ivana Chromková, Ing. Petr Bibora, Ing. Martin Vyvážil, Ing. Michal Frank

The paper describes research of utilization of solid wastes, which are produced during the manufacture of mineral wool. The aim of the four-year research is to verify the best way of processing of these waste materials and determine the maximum value of their addition into the construction materials, which will not have undesirable effect on requested properties of the final product. The verified applications are vibro-pressed thin-walled concrete blocks, thin-walled glass fiber elements, self leveling mixtures and thermal insulation panels.

6.10.2014
Ing. Bohumil Koželouh, CSc.,

Introduction – General − Timber joist ceiling – Timber ribbed floor (stressed skin panel) – Massive timber ceiling (glued laminated timber flat, Brettstapel ceiling, cross laminated timber, structural laminated veneer lumber) – Coupled timber-concrete ceiling.

28.9.2014
Ing. Martin Štěrba, Ústav technologie, mechanizace a řízení staveb, Fakulta stavební, VUT Brno

The article deals with the working safety regarding lifting mechanism in construction. The author mentions basic legislation that deals with this matter in the introductory part of the article. Then the author attempts to identify basic risks that are often present when lifting mechanisms are used in construction. The author also tries to emphasize the necessity to prevent the risks already in the preparatory phase of the project. The concluding part of the article contains the author´ s encouragement to increase the working safety in construction.

22.9.2014
Ing. Petr Ptáček, Ph.D., Ing. Monika Terebesyová, Ph.D.

In building practice, we often encounter problems of increased moisture in building materials or systems, because the most buildings are exposed to numerous sources of water in different forms. Long-term exposure to moisture in any part of the building structure (roof, walls, foundations...) has the effect of reducing the utility of the building and deterioration of its quality. Microwave heating treatment becomes one of the most effective methods of drying and sterilization of timber products.

21.9.2014
Ing. Bohumil Koželouh, CSc., soudní znalec

1. Placer River pedestrian bridge, Alaska, completed July, 2013. Glulam camelback truss bridge with clear span 83,5 m (280 foot), engineer Western Wood Structures, location Chugach National Forest, Alaska, Placer River. Width 4,5 m, walkway 1,8 m, 7,5 m above the water line, pedestrian load 4,4 kN/m2 (90 psf), snow load 9,7 kN/m2 (200 psf). Preservative-treated Douglas Fir glulam.
2. LeMay – America´s car museum, location Tacoma, Washington, completed spring 2012, engineer Western Wood Structures. The museum houses up to 350 cars, trucks and motorcycles. The curved roof system was created with glulam frames, glulam purlins with plywood sheating, rigid insulation and metal roof.
3. Office building from glulam post-and-beam structure and cross laminated timber in Kelowna, British Columbia/Canada. Three story structure completed in summer 2014 is respectful of its surroundings with low profile, yet modern in its angles and appearance. Cross-laminated timber provides an unprecedented level of structural integrity, design flexibility, and cost-competitiveness. On the exterior, CLT´s cantilever capabilities and key façade featrures.

15.9.2014
doc. Ing. Václav Kupilík, CSc.

Assessed white tanking is a part of flat block in residence zone in Prague. The flat block consists of three tower parts with reinforced concrete monolithically system. It has two underground storeys and it is built on the sloping plot of rectangular shape with the high difference of opposite corners more than 4 m. Arisen cracks in white tanking were sealed by grouting but infiltrated placed were appeared again. The recrystallization painting Xypex also did not help. Additionally realized drainage prevented water leakage.

řezivo
8.9.2014
doc. Ing. Jaroslav Solař, Ph.D., VŠB TU Ostrava

The contribution deals with the problems of the constructional protection of wood from holding water, from capillary rising and from condensation of vapour inside constructions that contain wood components. In the contribution there are formulated the fundamentals constructinal principles for the protection of wooden components against the stated types of hydrophysical strains.

4.8.2014
doc. Ing. Jaroslav Sandanus, PhD., Ing. Miloš Slivanský, PhD., Ing. Kristián Sógel, PhD.

In the paper the results of exceptional experimentation are presented, which focuses on the long-term loading of metal plate connected wood trusses. The uniqueness of research project is given by real dimensions of long-span samples and by the term of loading over one year. The aims of long-term experimentation were detection of two main parameters. The magnitude of additional deflections and time of load action needed for their development. In the paper the recommendations for producers of metal plate connected wood trusses and for structural engineers are mentioned. The purpose of that research project is to increase the safety and reliability of timber load-bearing structures.

21.7.2014
Ing. Marek Novotný, Ph.D., soudní znalec, ČVUT FA Praha, Ústav stavitelství

Failures of basement waterproofing is constatntly frequent subject of discussion among laymen and professionals. This issue is very topical especially with introduction of new materials. Paper deals with two groups of basement waterproofing failures, i.e. failures associated with building movement and failures caused by technological lack of discipline during concreting the basement. Both groups of failures are demonstrated by extensive photodocumentation.


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