Ústav technologie, mechanizace a řízení staveb
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- ItemThe effect of wind on extensive lightweight vegetated roofs(EDP Sciences, 2024-07-16) Sukopová, Dagmar; Mohapl, MartinNowadays, Lightweight vegetated roofs are becoming increasingly popular due to their light weight, low maintenance and water consumption. Even though they are mostly extensive greenery (staghorn bushes, mosses, etc.) they can provide urban areas with a few benefits. In particular, they can make an important contribution to improving the urban microclimate and reducing the negative urban heat island effect. They also contribute to the conservation of biodiversity by providing alternative refuges for a range of animals. However, due to their light weight, these lightweight systems may not withstand adverse weather conditions well, especially at the beginning of their construction. Wind resistance can cause them to erode and wind erosion of the growing medium can occur, especially when the root network is not yet sufficiently anchored in the vegetation system. Roof sections may be rotated, displaced, or even overturned, especially in the outer parts of the roof. The effects of wind action can also be influenced by the slope of Lightweight roofs. Roofs with a pitch of less than 30° may be subject to stronger wind suction effects. Existing research shows that, for example, roofs with a pitch greater than 35° have better resistance to wind pressure. This paper discusses different variants of existing solutions to the given problem.
- ItemNEGRAFICKÁ DATA A JEJICH STRUKUTRA PRO VYUŽITÍ LCA V BIM(Czech Journal of Civil Engineering, 2021-07-31) Brandtner, MichalČlánek se zabývá datovou strukturou pro účely posuzování životního cyklu staveb s využitím informačního modelu budovy (BIM). Posuzování životního cyklu (LCA) je metoda, využitelnápro prokázání vhodnosti navržených materiálů, konstrukcí nebo celých budov z hlediska životního cyklua jeho působení na životní prostředí. Pro samotné hodnocení LCA je stěžejní obstarat vstupní datapro tzv. inventuru životního cyklu (LCI). Cílem článku je definovat, jakou datovou strukturu je nutné získat z BIM modelu pro účely LCI. Nová metodika je postavena na základě informací z datové struktury standardizace negrafických informací modelu,zvané SNIM. Výhody představené metodiky byly prokázány na případové studii. Tyto výsledky jsou vhodné, pro rozšíření BIM modelu o nová data, nezbytná pro výpočty LCA.
- ItemTMELENÍ CEMENTOVÉ DESKY AQUAPANEL A NÁSLEDNÉ TAHOVÉ VLASTNOSTI TMELENÉHO SPOJE(Czech Journal of Civil Engineering, 2022-08-31) Boháček, Adam; Brandtner, MichalTento článek představuje výzkum zabývající se problematikou tmelení materiálů na bázi cementu a tahovými vlastnostmi tmelené spáry. Pro potřeby výzkumu prezentovaného v tomto článku je vybíráno několik druhů použitých materiálů. Jako podkladní materiál je vybrána cementová deska Aquapanel, dále jsou vybrány tmely a to konkrétně jeden zástupce tmelů akrylových a jeden zástupce tmelů polyuretanových. Ke zvoleným tmelů pak jsou použity primery, jež jsou zvoleny na základě doporučení výrobce. Z těchto materiálů jsou vyhotovena zkušební tělesa, které se po řádném vytvrzení a nakondiciování dále zkouší. Zkoušky probíhají podle postupů stanovených evropskou normou ČSN EN ISO 8340. Na základě výsledků zkoušky, lze ke tmelení podkladního materiálu prezentovaného v tomto výzkumu doporučit pouze tmel polyuretanový. Akrylový tmel vykazuje přílišná poškození po vystavení působení zkoušek.
- ItemFacade Renovation - Replacement and Restoration of the Panels in a Monument Protected Object(EDP Sciences, 2018-01-22) Novotný, Michal; Nečasová, BarboraThe article deals with problems of reconstruction of the facade and the associated problem of replacement or repair of the panels. In conventional buildings it is a smooth operation, but it is problematic in monument-protected objects. In the case of a common building, it is possible to choose any modern panels and simply replace them, but for historical objects we have to follow the claims and the rules of monument protection. In practice, it usually means the impossibility of use of modern panels, but at least a combination of old and modern technologies. Another possible solution to the problem is renovation, or repairs to the original state of the existing panels, of course with respect to the functionality of panels. The implementation of such repairs must always be based on the technical and historical survey of the condition of the object and the repairs must be professionally designed. Subsequently, corrections are made, during which it is necessary to pay particular attention to observance of the technological procedures, rules and instructions particularly in terms of monument protection. However, the functionality of the works or elements made with regard to the quality of the environment within the building is not negligible. A common problem is the lack of control of technical requirements and functional requirements. Underestimation of the problems then leads to difficult repairs. The article points to the mistakes and problems of one such construction project on a historically protected chateau building.
- ItemFire resistance of large-scale cross-laminated timber panels(IOP Publishing, 2017-12-21) Henek, Vladan; Venkrbec, Václav; Novotný, MiloslavWooden structures are increasingly being used in the construction of residential buildings. A common and often published reason to avoid wooden structures is their insufficient fire resistance, which reduces bearing capacity. For this reason, composite sandwich structures began to be designed to eliminate this drawback, as well as others. Recently, however, the trend is for a return to the original, wood-only variant and a search is underway for new technical means of improving the properties of such structures. Many timber structure technologies are known, but structures made from cross-laminated timber (CLT) panels have been used very often in recent years. CLT panels, also known as X-LAM, are currently gaining popularity in Europe. In the case of CLT panels composed of several layers of boards, they can be said to offer a certain advantage in that after the surface layer of a board has burnt and the subsurface layer has dried, oxygen is not drawn to the unburned wood for further combustion and thus the burning process ceases. CLT panels do not need to be specially modified or coated with fire resistant materials, although they are usually lined with gypsum-fiber fire resistant boards due to guidelines set out in the relevant standards. This paper presents a new method for the assessment of load-bearing perimeter walls fabricated from CLT panels without the use of an inner fire-retardant lining to ensure fire resistance at the level required by European standards (i.e. those harmonized for the Czech construction industry). The calculations were verified through laboratory tests which show that better parameters can be achieved during the classification of structures from the fire resistance point of view. The aim of the article is to utilize the results of assessment and testing by an accredited laboratory in order to demonstrate the possibilities of using CLT panels for the construction of multistorey as well as multi-purpose buildings in the Czech Republic.