Ústav technologie, mechanizace a řízení staveb
Browse
Recent Submissions
Now showing 1 - 5 of 61
- 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.
- ItemInfluence of Technological Procedures on Mechanical Properties of Bonded Joint(Springer Nature, 2018-12-24) Liška, Pavel; Nečasová, Barbora; Šlanhof, JiříIt would not be an exaggeration to say that adhesive joints have been an essential part of the construction industry for several decades now. However, a substantial disadvantage of bonded joints are the very strict requirements for adherence to the technological procedures defined by the manufacturers of assembly systems. Even a slight deviation from the recommended application steps can have a significant effect on the integrity of the entire system. In the research, five of the most common types of failure to comply with technological procedures in the realization of facade cladding were selected. The aim of the research project was to determine the extent to which a failure to adhere to technological procedures during facade construction can influence the effectiveness of the bonded joint. In construction practice, it is quite common during the implementation of a project that there are failures to comply with multiple requirements, or deviations from the prescribed procedures. For this reason, not only individual types of failure to comply with technological procedures were tested, but also their combinations. Altogether, 31 combinations of selected types of failure to comply with technological procedures were tested on one type of cladding. The adhesive joint was tested for shear strength and the adhesion of the adhesive to the substrate on a total of 352 samples. The results of the tests clearly confirm the hypothesis that failure to comply with technological procedures has a significant effect on the effectiveness of bonded joints. It is mainly the different combinations of failure to comply with technological procedures where the bonded joint loses effectiveness in the order of tens of percentage points.
- ItemAdhesion and Cohesion Testing of Joint Sealants after Artificial Weathering – New Test Method(Elsevier Ltd, 2017-06-02) Nečasová, Barbora; Liška, Pavel; Šlanhof, JiříThe use of construction sealants is an important area not just of the building construction. Each building requires a careful processing of all details and façades are no exception. From today´s point of view we may note that sealing of façade joints and different types of cracks, fissures or gaps is nothing unusual and, therefore, it is astonishing that there still occur defects that often cause a significant decrease of the durability of the structures and sealed structures. This paper deals with testing of a selected group of construction sealants at a so-called ‘real joint’. The real joint is a term defining a set of testing samples when the testing body contains a sealant applied in a manner corresponding to its real application. Cement bonded particleboard board was representing the façade cladding in this research since during the sealing there often occur complications with adhesion of sealants. For the presented experiment the existing testing methods that are used for verification of adhesion of cladding materials were studied and modified. According to the opinion of the authors those modified methods simulate well the parameters of the external environment and thus also the negative influences that may have a significant impact on the sealed joint in practice. The measured results prove that in the application of the sealants it is very important to follow the technology discipline and namely it is necessary upfront to verify whether the chosen materials are compatible. In most tested cases, diversion from the above-given steps resulted in failure of the sealed joint.
- 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.
- ItemRTS BIM PŘI NÁKLADOVÉM OCEŇOVÁNÍ(Czech Journal of Civil Engineering, 2022-08-31) Průcha, AlešTento článek je zaměřen na oceňování s využitím BIM, tedy informačního modelu budovy. Cílem tohoto článku je ocenit stavbu nákladovým způsobem pomocí BIM modelu. Obsahem článku je popis BIM problematiky, dále její zavádění a potřeba využití BIM ve stavebnictví. Článek popisuje metody ocenění a názorně zobrazuje ocenění vybrané konstrukce jednotlivými metodami. Hlavní oceňovací metodou je plugin RTS BIM, který využívá model vytvořený v programu Autodesk Revit. Toto nově představené řešení je poté porovnáno s položkovým rozpočtem, jakožto tradiční metodou ocenění stavby.