Publikační činnost Katedry pozemního stavitelství / Publications of Department of Building Constructions (225)

Permanent URI for this collectionhttp://hdl.handle.net/10084/106272

Kolekce obsahuje bibliografické záznamy publikační činnosti (článků) akademických pracovníků Katedry pozemního stavitelství (225) v časopisech registrovaných ve Web of Science od roku 2003 po současnost.
Do kolekce jsou zařazeny:
a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská-Technická univerzita Ostrava (VŠB-TUO),
b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

Bibliografické záznamy byly původně vytvořeny v kolekci Publikační činnost akademických pracovníků VŠB-TUO, která sleduje publikování akademických pracovníků od roku 1990.

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Now showing 1 - 20 out of 20 results

Mechanical properties of wooden elements with 3D printed reinforcement from polymers and carbon
(MDPI, 2024) Dedek, Jan; Juračka, David; Bujdoš, David; Lehner, Petr
The research presented in this article aimed to investigate the differences in mechanical properties between solid structural timber and the same reinforced element in three different ways. A three-point bending test was performed on wood elements reinforced with carbon-fiber-reinforced polymer (CFRP), 3D printed polycarbonate (3DPC) lamellas, and 3D printed polycarbonate with carbon fiber (3DPCCF) lamellas. In this comparison, the bending strength was large for CFRP samples, which have 8% higher performance than samples with 3DPCCF and 19% higher performance than samples with 3DPC. Conversely, when factoring in theoretical manufacturing costs, the performance of 3DPCCF is almost three times that of CFRP and 3DPC. In addition, 3D materials can be used for more complicated reinforcement shapes than those discussed in the paper.
Regeneration of panel housing estates from the perspective of thermal technology, sustainability and environmental context (case study of the city of Ostrava, Czech Republic)
(MDPI, 2023) Kubečková, Darja
The future of panel housing estates is influenced by a number of factors. Although panel housing estates have seen their share of commentary and analysis from both supporters and de tractors, there has been no comprehensive effort to explore the field of panel housing estates in terms of building thermal regeneration measures. This article focuses on the links between thermo-technical regeneration measures in panel housing estates, and the application of External Thermal Insulation Composite Systems (ETICS) and their impact on the urban environment of panel housing estates. The paper contains three main sections in which we (1) synthesize the literature, sources, building physics context, and assumptions for the occurrence of biodeterization in the facades of prefab residential housing located in housing estates; (2) compare the case studies and their results from the 2010–2021 field reconnaissance, in situ diagnostics, and laboratory analyses; and (3) identify/illustrate common features, the extent to which the quality of prefab residential housing located in housing estates with ETICS exterior surfaces is influenced by the environmental context, whereby we understand the whole process of the environmental assessment framework as an interrelated complexity of the interacting links between the environment, urban planning, architecture and construction sectors, supporting a holistic approach to the issue at hand. The results show that regeneration work, on the one hand, improves the urbanized environment and the energy potential of a housing estate; on the other hand, we encounter new manifestations of defects and disorders in the form of biodegradation of facades that we did not expect.
Probabilistic expression of the function of the change in prestressing force of timber elements depending on climatic conditions in situ
(Elsevier, 2023) Fojtík, Roman; Dubovský, Viktor; Kubíncová, Lenka; Stejskalová, Kateřina; Machovčáková, Eva; Lesňák, Michal
Today demand for sustainability forces us to use an ever-increasing share of renewable materials in construction and the associated increase in their mechanical resistance is related to this. The application of transverse prestress in timber structures will increase the overall stiffness and load-bearing capacity of the structural system. However, the prestressing force and subsequent rectification of the system depends on the relative environmental conditions for the specific location of the construction site. The climatic conditions have a significant impact on changes in the size of the prestressing force. Into the experimental sample, transverse prestressed was introduced by means of prestressing elements. The values of prestressing force and climatic conditions to which the sample was exposed were monitored and recorded. Based on experimentally obtained data, mathematical models were created and evaluated using methods such as principal component method and cross-validation method. The result of the analysis is the function for determining changes in the size of the prestressing force over time depending on the climatic conditions. Using this function, it is possible to determine the time when it is necessary to manually increase the amount of preload in the structure so that it correctly fulfils the purpose for which it was designed.
Software for the multi-criteria design of the external walls based on user priority
(MDPI, 2022) Majer, Jiří; Vavřínová, Nikola; Stejskalová, Kateřina; Pentková, Lenka
The external walls of buildings account for a substantial part of the financial costs of the entire construction, and there can be a loss of up to 35% of thermal energy through them. By properly optimizing the price for the construction of m(2) of the external wall structure and its thermal technical parameters, interesting savings can be achieved. At present, there is no multi-criteria analysis for designing external wall structure compositions involving broader input options according to the user's technical parameters and priorities. There is a large selection of special software in the Czech and European markets, but the software is focused only on the narrower area of design and ignores the issue of building material prices. The aim of this work is to create an algorithm that reliably finds the composition that best meets the user's requirements using a wide database of materials and selected mathematical methods. This article presents an algorithm that would design the ideal composition of an external wall. This algorithm has two options for searching. The first is based on eight technical criteria and the prices of materials used in combination with user priorities. The second option is to find the best composition based only on the specified interval of the selected technical parameters. Materials databases and the use of existing computational methods, such as the Saaty method and the WSM-weighted sum method, applied to the algorithm are essential to find the composition. According to the assignment, the structures will be clearly quantified in values from 1 (best) to 0 (worst). The algorithm, which is based on the analysis of data, sources, and theories of multi-criteria decision-making, should, therefore, facilitate the design of the external wall. At the end of this article, there is a verification of the functionality of the algorithm on a case study. We believe that software that uses the proposed algorithm could be very useful for practice.
Research of mechanical and thermal properties of composite material based on gypsum and straw
(Tech Science Press, 2022) Vavřínová, Nikola; Stejskalová, Kateřina; Teslík, Jiří; Kubenková, Kateřina; Majer, Jiří
This article is focused on the investigation of the mechanical and thermal properties of composite material that could be used for the production of plaster or plasterboards. This composite material is made of gypsum and reinforcing natural fibers. The article verifies whether this natural reinforcement can improve the investigated properties compared to conventional plasters and gypsum plasterboards made of pure gypsum. From this composite material, high-strength plasterboards could then be produced, which meet the higher demands of users than conventional gypsum plasterboards. For their production, natural waste materials would be used efficiently. As part of the development of new building materials, it is necessary to specify essential characteristics for their later use in civil engineering. Crushed wheat straw and three gypsum classes with strengths G2 (2 MPa)-gypsum class I., G5 (5 MPa)-gypsum class II. and G16 (16 MPa)-gypsum class III. were used to create the test samples. Samples were made with different ratios of the two ingredients, with the percentages of straw being 0%, 2.5%, and 5% for each gypsum grade. The first part of the article describes how the increasing proportion of straw affects the composite's mechanical properties (flexural strength and compressive strength). The second part of the article focuses on the change of thermal properties (thermal conductivity and specific heat capacity). The last part of the article mentions the verification of the fire properties (single -flame source fire test and gross heat of combustion) of this composite material. The research has shown that the increasing proportion of straw reinforcement caused a deterioration in the flexural strength (up to 56.49% in the 3. series of gypsum class II.) and compressive strength (up to 80.27% in the 3. series of gypsum class III.) and an improvement in the specific heat capacity and thermal conductivity (up to 31.40% in the 3. series). This composite material is thus not suitable for the production of high-strength plasterboards, but its reduced mechanical properties do not prevent its use for interior plasters. Based on the performed fire tests, it can be said that this composite material can be classified as a non-flammable material of reaction to fire Classes A1 or A2. From an ecological point of view, it is advantageous to use a composite material with a higher straw content.
Time connection of subsequent construction processes estimated by statistical method
(MDPI, 2022) Smugala, Stanislav; Kubečková, Darja
An integral part of managing the construction of investment units is the monitoring of labor productivity using statistical methods in combination with construction software. Such a combination includes a number of methods and modeling, among which is a method for determining the probability of the completion of construction processes based on the recorded mean value of labor productivity and its variations. For investment units consisting of two or more objects, it is necessary to assess the probability of the completion of construction processes related to follow-up activities and which are carried out by the same work crews. Based on the selected probability modeling, the aim of this contribution was to show how statistical methods and software support can contribute to savings in resources, both human and time, in construction production. The aspect is documented in a case study of residential buildings. The Lindeberg-Levy and Moivre-Laplace theory and the Bernoulli principle were used for mathematical modeling. The CONTEC construction software was applied as the software support. The performed modeling showed a decrease in the mean value of performance for all the processes examined compared to the planned values, except for the implementation of reinforced concrete monolithic structures. For these reasons, the working capacities had to be increased in order to meet construction milestones.
The quality of ETICS in the context of energy and social changes (case study)
(MDPI, 2022) Kubečková, Darja
The paper focuses on the quality of external composite ETICS (External Technical Insulation Composite System) facade systems from a long-term perspective in the context of energy and social changes and subsequent paths of housing construction, including reconstructions and renovations of prefabricated housing developments. These changes follow mainly from the EU energy concept and strategy in relation to housing and have an impact potential well beyond 2030. The aim of the paper is to show, based on field research and laboratory diagnostics on a selected reference sample of housing affected by biodegradation, to what extent the quality of ETICS facades is affected by technological aspects during the application of ETICS exterior plasters and during the implementation of photocatalytic coatings. The investigation shows that the influence of the human factor is one of the main aspects of negative impacts.
Mechanical, thermal, and fire properties of composite materials based on gypsum and PCM
(MDPI, 2022) Stejskalová, Kateřina; Bujdoš, David; Procházka, Lukáš; Smetana, Bedřich; Zlá, Simona; Teslík, Jiří
One of the solutions for overheating the interior in the summer without increasing energy consumption is the integration of phase change material (PCM) into interior plasters. However, adding PCM to plasters deteriorates their properties and thus their usability. The aim of this paper is to determine how the microencapsulated PCM affects the mechanical, thermal, and fire properties of plasters and how much PCM can be added to the plaster. Two sets of samples were prepared: in set S, part of the aggregate was replaced by PCM; and in set R, only PCM was added. The bulk density, flexural strength, compressive strength, tensile strength perpendicular to the surface, thermal conductivity coefficient, specific heat capacity, melting, and solidification temperatures and enthalpy were measured. A single-flame source fire test and a gross heat of combustion fire test were performed to determine the reaction to the fire class. The results show that with an increasing proportion of PCM, the strength of the samples of set R decreased more significantly than it did with the samples of set S. It was found that only up to about 10% PCM could be added to set R, while up to 30% PCM could be added to set S.
Experimental investigation of two test setups on straw bales used as load-bearing elements of buildings
(MDPI, 2021) Lehner, Petr; Horňáková, Marie; Vlček, Pavel; Teslík, Jiří
The importance of green and sustainable materials in civil engineering is undeniable. Alongside modern practices that improve the properties of standard building materials, there are ways to revive forgotten techniques, including straw bale buildings. Straw bales are load-bearing structures, which are applied based on handed-down experience and lack standard approaches in testing, design, and application. Therefore, a goal ahead is to describe every aspect of the process in technical detail. The objective of this paper is to highlight practical ideas for testing straw bales on a hydraulic press machine and to provide a basic statistical investigation of the results obtained. Two basic series were prepared, one without a side barrier and the other with a side barrier. The reason for this was to delineate the limits of the real behaviour of the straw bale on the load bearing wall of the house. Due to the assumed slight embedment of adjacent bales, the real result were within these limits. The experimental plan, basic results, simplified correlations, and statistical evaluation are presented. Recommendations for a further testing and evaluation are provided. As expected, the results with and without the lateral barrier differ by almost 18% for the true strain.
Analysis of the fire properties of blown insulation from crushed straw in the buildings
(MDPI, 2021) Teslík, Jiří
Sustainable development in civil engineering is the clear and necessary goal of the current generation. There are many possibilities for reducing the use of depletable resources. One of them is to use renewable and recyclable materials on a larger scale in the construction industry. One possibility is the application of natural thermal insulators. A typical example is a crushed straw, which is generated as agricultural waste in the Czech Republic. Due to its small dimensions and good thermal insulation parameters, this material can also be used as blown thermal insulation. The research aims to examine the fire resistance of crushed straw as blown insulation. The single-flame source fire test results, thermal attack by a single burning item (SBI) test and large-scale test of a perimeter wall segment are shown. The results show that blown insulation made of crushed straw meets the requirements of fire protection. In addition, crushed straw can be also used to protect load-bearing structures due to its behaviour. This article also shows the production process of crushed straw used as blown insulation in brief.
Assessment of the summer thermal stability of the attic room using two different software
(De Gruyter, 2020) Stejskalová, Kateřina; Vavřínová, Nikola
This paper presents the calculations of the summer thermal stability of a critical room of the given building. In this case, the critical room of the building is an attic room. Using two different software (SIMULACE and DesignBuilder), the summer thermal stability of the attic room was evaluated according to the Czech standard CSN 73 0540-2 [1]. This standard compares the calculated and required value of the maximum internal temperature in the summer period. The results from both software were compared with the Czech standard and also with each other. The resulting temperature courses in the interior differ by a few Celsius degrees. In conclusion, the causes of different results are discussed as well as the advantages and disadvantages of both software.
Moisture at contacts of timber-concrete element
(Výskumný ústav papiera a celulózy, 2020) Fojtík, Roman; Kubíncová, Lenka; Dubovský, Viktor; Kozlová, Kateřina
The subject of the article is to monitor the changes of moisture on the contact surface concrete and timber part of the composite timber-concrete beam. The moisture directly affects the properties of timber and causes its volume changes and degradation processes. These effects reduce of durability and load capacity of the structures. The beam was placed at the exterior. The observed contacts of the beam are often critical on real structures, as it is difficult to repair and maintenance in the case of increasing moisture or intrusion of dirt. The experiment was used to monitor and evaluate the dependence of changing moisture in contacts depending on ambient environmental conditions.
The indoor microclimate of prefabricated buildings for housing: Interaction of environmental and construction measures
(MDPI, 2020) Kubečková, Darja; Kraus, Michal; Juhásová Šenitková, Ingrid; Vrbová, Magdaléna
The current knowledge shows that the interior microclimate of residential buildings that were constructed between 1950 and 1990 using panel construction, not only in the Czech Republic but also in Europe, and were renovated in accordance with applicable legislation related to thermal comfort and energy is significantly affected by gaseous pollutants. At increased concentrations and exposure times, these pollutants negatively affect the interior microclimate and at the same time have a negative effect on the health of users. After the implementation of remediation measures, which are mainly focused on improving the thermal technical parameters of the building envelope, the concentration of CO2 in the indoor environment increases. Carbon dioxide is one of the most important active factors and in terms of the quality of the interior microclimate, it is considered a reliable indicator of whether the interior microclimate can be considered a healthy and favorable environment. It is thus clear that the set and de facto systematized measures in the renovation of the housing stock from the second half of the 20th century has led to energy savings on the one hand, but on the other hand, this has contributed to the hygienic damage of housing units and an unhealthy interior microclimate. The paper aims to define the interaction of interdisciplinary contexts that have led to an increase in the indoor air quality (IAQ) of renovated residential panel buildings.
Prestress losses in spruce timber
(Výskumný ústav papiera a celulózy, 2020) Fojtík, Roman; Dubovský, Viktor; Kozlová, Kateřina; Kubíncová, Lenka
Prestressing force and its change is one of the key factors that affect wooden constructions, especially those using methods of transverse prestressing. To achieve a description of a prestress force (P) in transversally prestressed wooden constructions a simulated experiment was done. Prestressing force, external temperature, and moisture were measured during 669 days. The main goal of this article was to model the primary losses of the prestress force at the spruce element of the 138 x 138 mm cross-section with the sensor installed. For this purpose, all measurements were statistically analyzed and the period of primary loss was found. During this period the prestress force was decreasing with time mainly and the influence of temperature and moisture could be omitted. Based on this analysis a mathematical model of losses of the prestress force was found as P = 8.538-0.014.day.
Research of the fiber reinforced strain hardening cementitious composite with high volume of industrial by-products
(Stowarzyszenie producentow cementu, 2019) Jašek, Marek; Stejskalová, Kateřina; Hurta, Jan; Brožovský, Jiří
This work aims at experimental investigation of several variants of fiber reinforced cementitious composite with strain hardening made partially with industrial by-products. This paper describes the manufacturing, testing and evaluating the properties of the composite. Industrial waste produced mainly in Moravia-Silesia Region in the Czech Republic was used for the manufacturing of the fiber reinforced cementitious composite with strain hardening. The basic physical and mechanical properties were measured - volume density of wet and hardened composite, consistency, tensile, flexural and compressive strength and elastic modulus. The findings show that the fiber reinforced cementitious composite made partially with industrial by-products is a suitable material for sustainable constructions.
The impact of changes in the geological conditions of road bedrock layers while the road was in use
(University of Zagreb, Faculty of Civil Engineering, 2019) Smugala, Stanislav; Kubečková, Darja; Indra, František
This article examines the effective road reconstruction technologies applied during construction processes to ensure the required final quality of construction work. The construction quality and especially the overall levelness of roads are influenced by several factors. These factors include high-quality implementation of road structural layers, including active zones, which can be adversely affected by the undisciplined application of technology, insufficient engineering and poor geological surveys. Suitable and effective reconstruction technology provides the required quality of construction work yet does not significantly extend construction time. The authors propose stabilisation using cement or lime during reconstruction. This stabilisation method is used if the structure of the bedrock layers is finely granular. The stabilisation process consists of excavating the unacceptable bedrock layer and mixing it with additives and water. A principally different bedrock stabilisation method consists of completely replacing it with a gravel layer, which is used when individual base layers are diverse and stabilisation using additives would not guarantee the required results, i.e. improved strength characteristics. In some cases, the existing base layers are not suitable for use as road base layers because of their characteristics, such as volumetric instability. For this reason, they must be replaced with more suitable materials. This topic is documented by a practical example.
Infrared thermographic measurement of the surface temperature and emissivity of glossy materials
(Sage, 2018) Alexa, Petr; Solař, Jaroslav; Čmiel, Filip; Valíček, Pavel; Kadulová, Miroslava
Determination of the surface temperature and emissivity of glossy materials is a complicated task due to the relatively wide range of emissivity values and the reflection of infrared radiation from surrounding objects. As a consequence, standard methods used in infrared thermography are not applicable. In this article, an alternative method is proposed for the measurement of the surface temperature and emissivity of glossy materials used in the external structures of buildings that is based on an external source of thermal radiation. It is shown that the method gives quite accurate values of emissivity of both low- and high-emissivity glossy materials, whereas the surface temperature of low-emissivity glossy materials is less accurate and strongly depends on the accuracy of the used thermal camera.
Determination of the airborne sound insulation of a straw bale partition wall
(De Gruyter, 2017) Teslík, Jiří; Fabian, Radek; Hrubá, Barbora
This paper describes the results of a scientific project focused on determining of the Airborne Sound Insulation of a peripheral non-load bearing wall made of straw bales expressed by Weighted Sound Reduction Index. Weighted Sound Reduction Index was determined by measuring in the certified acoustic laboratory at the Faculty of Mechanical Engineering at Brno University of Technology. The measured structure of the straw wall was modified in combinations with various materials, so the results include a wide range of possible compositions of the wall. The key modification was application of plaster on both sides of the straw bale wall. This construction as is frequently done in actual straw houses. The additional measurements were performed on the straw wall with several variants of additional wall of slab materials. The airborne sound insulation value has been also measured in separate stages of the construction. Thus it is possible to compare and determinate the effect of the single layers on the airborne sound insulation.
Principles of the four-point thermographic measurement of the surface temperature and emissivity of glossy materials
(Wiley, 2016) Čmiel, Filip; Solař, Jaroslav; Alexa, Petr
The emissivity and surface temperature of glossy materials are measured in IR thermography by covering the surface with a material with the known emissivity. The quantities can be, however, determined without using materials with the known emissivity. IR radiation is reflected from the measured glossy surface and a thermographer detects such reflection. This paper discusses the measurement of the surface temperature and emissivity of glossy materials which are used in external structures of the buildings – for instance, windows, light external walls or tiles. A four-point method is proposed for a more accurate determination of the surface temperature and emissivity of glossy materials. Results of successful laboratory and field tests of the method are presented.
Unique documentation, analysis of origin and development of an undrained depression in a subsidence basin caused by underground coal mining (Kozinec, Czech Republic)
(Springer, 2014) Marschalko, Marian; Yilmaz, Işık; Lamich, David; Drusa, Marián; Kubečková, Darja; Peňáz, Tomáš; Burkotová, Tereza; Slivka, Vladimír; Bednárik, Martin; Krčmář, David; Duraj, Miloš; Sochorková, Alena
This article aims to explain and demonstrate the origin and development of a subsidence basin caused by coal mining as well as to point out important aspects of this phenomenon in engineering geology. Engineering geology needs to deal with a number of issues related to the origin and development of subsidence basins in areas affected by deep coal mining. An interesting case study from the Upper-Silesian Basin in the northeast of the Czech Republic near the Polish border is presented in this paper. There is a clear time chronological succession in the ground surface changes manifested by a ground subsidence gradation, both in their absolute values as well as in their spatial distribution. The phenomenon is documented by aerial photo time series, which optimally depict the origin and development of the subsidence. In the study area, there are changes in the landscape elements and it is essential to be considered in future land use plans. The marginal conditions of the Quaternary geological structure and hydrogeological conditions are responsible for an unconfined aquifer which manifests there as a water body in an undrained depression in the course of the ground subsidence.

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