rss_2.0Sciendo RSS Feed for Slovak Journal of Civil Engineeringhttps://sciendo.com/journal/SJCEhttps://www.sciendo.comhttps://sciendo-parsed.s3.eu-central-1.amazonaws.com/651653807aef280fe729d1dd/cover-image.jpghttps://sciendo.com/journal/SJCE140216https://sciendo.com/article/10.2478/sjce-2024-0012<abstract> <title style='display:none'>Abstract</title> <p>The interval of time after pouring concrete is an important factor, which directly affects the timing and cost of construction. The case study that was investigated in this research, is a tunnel project located in Iran. Eighteen mix designs were prepared using properties such as different water-cement ratios and the use of two types of superplasticizer with different dosages. The optimal mix designs among the samples were separately specified.</p> <p>Concrete mix designs with different curing ages were made to specify the minimum curing time in which the concrete could gain the required compressive strength. Moreover, the concrete’s compressive strength was measured for different ages in order to determine the minimum time interval. For a better insight, two mathematical equations were derived to estimate the minimum curing time and time interval. Finally, a statistical analysis was conducted in order to determine the proper time intervals. Moreover, the analysis specified the impact rate of the research parameters (i.e. the type and dosage of superplasticizer, curing time, and water-cement ratio) on the compressive strength</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00122024-07-03T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2024-0009<abstract> <title style='display:none'>Abstract</title> <p>Ensuring the sufficient residual resistance of glass structures after the failure of one glass ply to the failure of all the glass plies is an integral part of the design of glass structures. This paper presents an experimental study of bolted connections in laminated glass during three stages of a glass specimen: an intact glass specimen, a specimen with one ply of glass broken, and a specimen with both plies of glass broken. The effect of the type of glass was observed. The experiment proved that laminated glass made from thermally-toughened glass with bolted connections in its unfractured state has significantly higher resistance than laminated glass made from annealed glass. In a state of both plies of glass broken, the specimens made from annealed glass showed a higher residual resistance than specimens made from thermally toughened glass. The performance at this stage was also influenced by the temperature and loading speed. The expected strength of the glass was calculated on the basis of numerical models.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00092024-07-03T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2024-0010<abstract> <title style='display:none'>Abstract</title> <p>Facilities for children and young people should be established in a healthy environment that is protected from external health-damaging factors, such as noise, air pollution, and negative educational influences. A school building should also be a safe and healthy environment for pupils and students, as legally required. However, although some school buildings have been renovated, most were constructed in the last century, and their indoor microclimate remains unsatisfactory. Schools must maintain optimal thermal and humidity conditions to ensure the healthy development of children and their ability to function properly in a classroom. While natural ventilation through opening windows is a good practice, it may not always guarantee sufficient air exchange, especially for schools located in busy traffic areas. This paper presents experimental measurements and a comparison between two primary schools in Bratislava, which describes the current thermal and humidity conditions in the indoor environment of both schools. Experimental measurements were carried out on five school days in each primary school to determine the thermal-humidity conditions and indoor air quality, depending on the concentrations of carbon dioxide.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00102024-07-03T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2024-0008<abstract> <title style='display:none'>Abstract</title> <p>In the paper, we present the results of an analysis of data samples of 282 damaged buildings; the samples include the age of the building, the type of vertical bearing structures, the type of construction of the external walls, the method of the insulation of the walls, the number of floors, the buildings’ functions, and the extent of the damage. The primary objective of the analysis was to evaluate the possibility of using panels of cold-formed thin-walled steel profiles to repair the damaged structures. The results of a study of typical projects of large panel buildings that were constructed in Ukraine and an analysis of the practical experience of repairing these types of buildings after blast actions can also be found. The research tasks are defined for implementing this technology in the process of repairing large panel buildings.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00082024-07-03T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2024-0011<abstract> <title style='display:none'>Abstract</title> <p>The objective of this study is to assess the impact of incorporating rubber tire waste and brick fillers as a substitute for sand in cement mortar samples. The evaluation includes measurements of the bending strength, dynamic modulus of elasticity, and displacement. The replacement of sand by rubber waste (RW) and brick waste (BW) at 0%, 10%, 20% and 30% for rubber waste and 0%, 2.5%, 5.0%, 7.5%, and 10% for brick waste by volume was experimentally conducted. According to the findings, the introduction of rubber waste leads to a significant reduction in the flexural strength, dynamic modulus of elasticity, and displacement. The brick waste can be considered a suitable filler, which minimizes the negative effect of rubber tires and tends to result in suitable mixtures. The optimal values (10.10% for the RW and 10% for the BW) showed good agreement with the experimental results, with differences of 1.85%, -4.73%, and -4.48% for the displacement, flexural strength, and dynamic elastic modulus, respectively.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00112024-07-03T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2024-0013<abstract> <title style='display:none'>Abstract</title> <p>The transportation network is the most important component of an urban infrastructure. The efficiency of a region’s transportation system can be understood by the effectiveness of its transport network arrangement. The current study employs Geographical Information Systems (GIS) to assess the structure of a transport network in various clusters of the Hyderabad Metropolitan Area (HMA). The study focuses on a thorough assessment of the transport (or) road network structure in terms of various criteria such as connectivity, accessibility, maturity, and development. The study also categorizes each Transport Network Structural Evaluation Criteria (TNSEC) level as “very low, low, medium, high, or very high”. The goal of this research is to create a Road Network Structural Performance Index (RNSPI), which is usually used to measure the efficiency of a study area’s transportation network structure. The study’s findings serve as a foundation for city transportation planners to put efforts in the planning to enhance network facilities in the study region. The study also investigates the utility of Arc GIS software in assessing the structure of an urban transport network.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00132024-07-03T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2024-0003<abstract><title style='display:none'>Abstract</title> <p>This article reports on the development, validation, workflow and implementation of a simplified method for evaluating the non-visual (melanopic) potential of daylight in typical side-lit rooms. The method is suitable for climatic areas with a dominant occurrence of cloudy skies. The non-visual daylight evaluation tool is based on a modified average daylight factor method. A simplified daylighting model improves the calculation of the vertical daylight factor and the passage of daylight through a vertical lighting opening. The proposed calculation method makes it possible to determine the illuminance of a vertical plane in the interior. The method is based on the uniform sky and the external diffuse horizontal illuminance at the location of interest. The outputs of the tool can also be used to quickly estimate visual levels of daylight. The article also proposes a classification of the availability of melanopic daylight in side-lit rooms, which is based on the outputs of the proposed calculation method.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00032024-03-30T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2024-0005<abstract><title style='display:none'>Abstract</title> <p>The relationship between stress and strain tensors in soil is described by the soil constitutive equation, which depends on the soil type and deformation conditions. The development of various constitutive models has enabled a better understanding of the macromechanical properties of soil. One such model is hypoplasticity, which was discovered more than three decades ago. The purpose of this study is to determine whether hypoplasticity could accurately represent the behavior of Danube sand, a specific type of sand. The researchers conducted laboratory measurements to obtain the eight basic hypoplastic parameters of Danube sand and employed the intergranular strain concept as an extension of hypoplasticity to achieve a more precise material behavior. All the parameters were then utilized to simulate the cyclic triaxial test using the SoilTest Module of PLAXIS. The results showed that the hypoplastic constitutive simulation model for Danube sand was capable of making relatively accurate predictions for accumulative settlement.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00052024-03-30T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2024-0004<abstract><title style='display:none'>Abstract</title> <p>The concept of smart cities is gaining momentum with efforts to go greener and be more sustainable along with the growing demand for data-driven policies. The European Union (EU) is highly committed to fostering sustainable urban development through targeted funding programs that encourage innovation, collaboration, and practical solutions for climate-neutral and smart cities. We have used data mining on the data of the Community Research and Development Information Service (CORDIS) and Eurostat during 2014 – 2022, to analyze such projects. Firstly, we can report that in absolute measures, Germany, Spain, France, Sweden and Lithuania have obtained the largest amounts of money fromthe EU Horizon program to support the development of smart cities. Secondly, we have found that when accounting for the size of funding per capita, Estonia leads in terms of funds invested in smart cities followed by Luxembourg, the Netherlands, Finland, and Cyprus. Focusing our attention on the cost of outcomes, i.e., the efficiency of spending funds on smart cities, we can see that the leading countries in the EU are Romania, Switzerland, Norway, and Luxembourg. The authors have compared the success of European projects in their different phases, while considering the overall results as most relevant for our evaluation.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00042024-03-30T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2024-0006<abstract><title style='display:none'>Abstract</title> <p>As part of a change in the division of transport work, bicycle transport has made the most progress in recent years. As the largest city in Slovakia Bratislava, is trying to keep up with foreign cities. In recent years, it has developed projects that have made it possible to increase the development of cycling in the city. The last major cycling survey was conducted in 2011 by Cyklokoalicia. This survey aims at determining the momentum of bicycle traffic by identifying its greatest shortcomings or, conversely, the most positives. The data from the analysis given will also be used to develop a concept for the development of bicycle transport in the city of Bratislava.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00062024-03-30T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2024-0001<abstract> <title style='display:none'>Abstract</title> <p>Faced with the increasingly growing need for construction material resources and the strict requirements and conditions for preserving the environment, it has become necessary and relevant to study all possibilities and opportunities for the recycling and valorization of industrial waste and by-products in the construction field. Strapping straps is a product used to bundle and transport goods and construction materials. After its use, it is considered as waste. The objective of this experimental work is to study the possibility of reusing the strapping strap waste as fibers in the production of fiber-reinforced concrete. For this purpose, three families of concrete were composed using strapping strap fibers, steel fibers, and polypropylene fibers, which were introduced into a concrete composition by volumetric substitution (0.4%, 0.8% and 1.2%) of aggregates. The fresh properties were evaluated through slump, density and air content tests. Hardened properties were investigated using the compressive and flexural strengths, pulse velocity, dynamic elastic modulus, and water absorption tests. The results obtained showed that strapping strap waste fibers significantly improve the mechanical properties of fiber-reinforced concrete and have a behavior similar to that of steel fibers. The optimum rates of strapping strap fibers were 0.4% and 1.2% for compressive and flexural strengths respectively. Compared to polypropylene fibers, the strapping strap fibers were found to be more efficient and led to a gradual increase in flexural strength with an increase in the strapping strap fibers. The results obtained also showed that the increase in strapping strap fiber content gradually increased the water absorption of fiber-reinforced concrete.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00012024-03-30T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2024-0002<abstract><title style='display:none'>Abstract</title> <p>This study presents a numerical approach to an analysis of the mechanical behavior of double-layered tensegrity grids. We present a comparative study on the behavior of tensegrity grids through geometric nonlinear analysis (GNA) and combined nonlinear analysis (CNLA) (geometric and material), considering the possible effect of evolution in the elasto-plastic domain of the cable elements. The effect of the relaxation of cable on the amplification of the displacement of these grids was taken into account. The updated Lagrangian formulation, which modifies the Newton-Raphson iterative scheme with incremental loading, was adopted. We have developed a numerical computational model specific to tensegrity structures that simulates the geometric and material nonlinear behavior. The reliability of the calculation tool developed has been validated. Additionally, the results of the application of the numerical model on a grid, which was generated based on demi-cuboctahedral tensegrity cells, are presented.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00022024-03-30T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2024-0007<abstract><title style='display:none'>Abstract</title> <p>In countries that are big producers of olive oil such as Spain, Italy, or Greece, large amounts of olive husk remain as waste from processing olives and pose a serious environmental issue. One of the solutions could be to use this waste to partially replace sand in cement mortar to preserve the environment, decrease the consumption of cement, and improve economic benefits. This work presents our initial results which show the viability of using olive waste as an aggregate in cementitious mortars, indicating that the organic materials studied can be promising for this purpose.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2024-00072024-03-30T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2023-0026<abstract> <title style='display:none'>Abstract</title> <p>The dynamic penetration test was used to investigate the angle of shear strength of Danube gravel. The correlations for its determination are available in the standards and literature. From the data set of the results, the characteristic value of the angles of shear strength was derived according to the recommended statistical procedure from the second generation of Eurocode 7. The characteristic values of the angle of shear strength were evaluated for well-graded gravels, poor-graded gravels, and gravels with fine-grained particles of the Danube. The correlations, which were based on field tests and considered the genesis of the soil, were compared with laboratory test results and a table of the values from the Slovak standard, which are used for purposes of comparison.</p> <p>In our research we compared the characteristic field values of the angle of shear strength obtained in the laboratory to observe the effect of their genesis on the appropriateness of the correlations used. We conclude with recommendations for the regional correlations and suggest values of the angle of shear strength for the classes of gravels tested.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2023-00262023-12-27T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2023-0021<abstract> <title style='display:none'>Abstract</title> <p>In this study, the microbiologically-induced calcium carbonate precipitation (MICP) method was employed to examine its potential for repairing cracks in concrete. In addition, specific gravity and porosity values were measured to examine the effect of calcite formations on concrete surfaces and microstructures. Bacteria-supplemented concrete repaired cracks up to 0.4 mm wide by filling them with CaCO3. Furthermore, this study not only examined the healing of the width but also the length of cracks. However, as the width of the treated cracks decreased, their length increased. This indicated that the MICP treatment is more effective in a limited crack range. Specific gravity values increased, and porosity values decreased in concrete supplemented with calcifying bacteria. SEM analyses showed that calcite is a bacterial product that forms a very tight bond with a cement gel and that calcite fills visible cracks and voids and creates more of a void-free and undamaged concrete structure.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2023-00212023-12-27T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2023-0024<abstract> <title style='display:none'>Abstract</title> <p>This study evaluates the performance of concrete under the effect of the addition of non-straight fibers recovered during the machining of steel parts and then studies the effect of the addition of corrugated fibers (chips) on their behavior in direct traction of the fiber concrete. In order to characterize the mechanical behavior and tearing of these fibers, three lengths of fibers were used (4 cm, 5 cm, and 6 cm); for each length we varied the percentage by volume (0.3%, 0.5%, 0.8%, 1%, and 1.2%). To make a comparative study, a second series of tests was carried out with control concrete (BT) without any fibers of the same composition. The results of the tests carried out indicate that the resistance and stiffness are significantly improved and that the fibers imparted significant ductility to the material compared to the control concrete. It was also observed that the percentage of fibers significantly influences the appearance of cracks. Moreover, with an increase in the percentage of fibers from 0.3% to 0.8%, the resistance increases, but beyond a content of 0.8%, the mechanical characteristics decrease.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2023-00242023-12-27T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2023-0023<abstract> <title style='display:none'>Abstract</title> <p>Algeria is currently undergoing an evolution in civil engineering, which has resulted in a higher use of aggregates, especially sand. This study contributes to the development of locally produced materials. Its goal is to explore how the type of sand and waste marble powder (WMP), which can be used as a partial replacement of cement and aluminum powder (Al) with different percentages as an expansive agent, can affect physico-mechanical properties such as the bulk density and mechanical strength at 28 and 90 days, as well as the thermal conductivity of lightweight cellular concrete. Non-autoclaved cellular concretes (CC) were investigated based on three types of sand, i.e., sea sand (SS), river sand (RS), and waste marble sand (WMS); a hydraulic binder (a mix of cement and waste marble powder), and aluminum powder. The experimental results indicate that the nature and particle size distribution of the sand used had an impact on the properties of the CCs. Furthermore, it can be seen that the increased aluminum contents decrease the density, mechanical strength, and thermal characteristics of the CCs. Using 10-15% WMP as a cement substitute improves the mechanical strength, offers better thermal conductivity values, and contributes to sustainable development by developing a new class of environmentally friendly cellular concrete.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2023-00232023-12-27T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2023-0027<abstract> <title style='display:none'>Abstract</title> <p>Horizontal green areas are becoming valuable, yet extruded spots, and their constant elimination at the expense of commercial and housing developments is disrupting green infrastructure. Interlocked existing urban structures seldom allow for the creation of parks and larger green open spaces, which could provide a habitat for a wide range of insects, birds, and other small animals. The lack of green spaces causes urban heat islands (UHI) over the cities. Vertical gardens are alternative solutions for urban areas, where it is not possible to increase biodiversity by creating new horizontal green areas. They effectively utilise surfaces that would otherwise be unused and transform them into effective green infrastructure elements.</p> <p>Using the example of the historical city district of Bratislava, i.e., Old Town (Staré Mesto) in Slovakia, we present an alternative approach for resolving the lack of green areas. A case study was conducted to create a map of all the potentially suitable areas for the construction of vertical gardens. We divided these spots into three groups, i.e., walls, columns, and free-standing structures and proposed construction methods for each type. Regarding the placement of potentially suitable areas along the roads connecting important transport hubs with the city centre, we created an original proposal for a district-wide network of vertical gardens as orientation elements for tourists and residents with significant aesthetic merit as well as ecological and hygienic values.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2023-00272023-12-27T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2023-0025<abstract> <title style='display:none'>Abstract</title> <p>The article focuses on an analysis of the indoor climate in a small, newly-built auditorium. Providing optimal indoor climate parameters in the interiors of a university is extremely important for students. Meeting these parameters is essential not only from a physiological point of view, but also to achieve desirable student performances. The parameters of CO2 concentration are also influenced by the air distribution system in a small auditorium. The correct positions of the supply and extract air is very important. The first experimental measurements of CO2 concentration were carried out in a small auditorium in an old building. The natural ventilation of the small auditorium was evaluated. The second experimental measurements of the CO2 concentration were made in a small auditorium in a newly-built building. The ventilation system and the modern air distribution system of the small, newly-built auditorium were evaluated based on the CO2 concentration and the PMV index. A Testo 480 was used for the measurements. The conclusion of this paper contains the recommendations for the design of a newly-built ventilation system in a small auditorium.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2023-00252023-12-27T00:00:00.000+00:00https://sciendo.com/article/10.2478/sjce-2023-0022<abstract> <title style='display:none'>Abstract</title> <p>Reinforcing soft soils with good drainage and load-bearing material is a common practice in the construction of embankments. Stone columns are among the granular materials that accelerate consolidation settlements due to their high drainage capacities. This study aims to investigate the behavior of an embankment on stone column-reinforced soft soil. The embankment was analyzed using the Plaxis 2D Finite Element Method. The columns were converted into equivalent walls using the plane strain conversion method. This method was validated with field measurement results from previous studies and showed good agreement. According to the research findings, stone columns significantly reduced deformations and improved consolidation. For instance, the ultimate settlement was decreased from 54.3 mm to 33.1 mm for 10% and 20% area replacement ratios, respectively. As the safety analysis verified, basal geosynthetics contributed substantially to the embankment’s stability. Furthermore, the safety factor values increased for all stages of the construction, and the global safety factor increased at the end of the construction. Stone columns and basal geogrid-reinforced soft soil can reduce settlement and increase the stability of an embankment.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/sjce-2023-00222023-12-27T00:00:00.000+00:00en-us-1