Abstract Failures of structural elements in historical roof trusses pose a significant challenge in the preservation and restoration of a cultural heritage. These trusses, traditionally constructed from wood, are exposed to various factors that contribute to their degradation and damage. The most common factors include moisture, insect activity, fungal decay, and mechanical damage caused by geometric deformations or unprofessional alterations. These defects can compromise the structural integrity of an entire roof truss construction and jeopardize the stability of the building. The restoration and conservation of historical roof trusses require a specialized approach involving detailed diagnostics, modern technologies, and the preservation of original construction elements. This paper focuses on identifying the most common structural defects in historical roof trusses, analysing their causes, and presenting possible repair methods aligned with the protection and care principles of a heritage.

Abstract The study investigates the interaction between the grout curtain and bedrock foundation of the Nosice Dam, which is located in a geologically heterogeneous environment on the Váh river in Slovakia. By applying numerical modeling (the Finite Element Method) and analyzing water pressure test data, the research aims to assess the effectiveness of a grout curtain in controlling seepage. An extensive parametric study examines the impact of different rock permeability values on the reduction of seepage, which aids in the optimization of the depth of a grout curtain. This approach underscores the importance of advanced numerical modeling for dam safety and seepage control. The results could contribute to the knowledge of dam seepage control measures and could provide valuable insights about similar hydraulic structures. They could potentially mitigate risks, such as internal erosion and foundation instability associated with uncontrolled seepage.

Abstract An analysis of the effect of the covering of a ruin by a flat roof of various sizes and positions is presented. The ruin has almost cube-like proportions, with an open roof plane and an open destroyed corner. The coverage of the ruin by a roof is viewed as protection against wind and its associated destructive mechanisms. The effect of the wind flow is illustrated by the minimum and maximum values of the external pressure and the skin friction coefficients. Taking the changes of these values into account, the degree of protection of the ruin by the flat roof alternatives is estimated, and the optimal alternative for the coverage is discussed. Simulations of the wind study were conducted using the Fluent by Ansys, computational fluid dynamics software, 3D Time Steady Reynolds-Averaged Navier-Stokes equations, and the Shear Stress Transport k-ω turbulence model.

Abstract This paper presents the findings of theoretical and empirical research in the area of sustainable Construction 4.0. In the theoretical part of the article, the findings of the potential of BIM technology to support the development of sustainable Construction 4.0 which are based on a literature review study of the works published in the examined area are presented. In the empirical part of the work, the article discusses findings related to the potential of BIM technology in the specific dimensions of sustainable Construction 4.0 based on expert assessments of a sample of 94 experts in construction sector in Slovakia. The potential of BIM technology was identified for social, economic and environmental dimensions of the development of the development of sustainable Construction 4.0. The significance of the differences among the expert estimates for the different sustainability dimensions and among the expert groups are verified.

Abstract The paper describes research focused on the design of a technical vertical slot fish pass. Based on measurements of the depths and velocities conducted on a hydraulic model of a fish pass at the Water Research Institute Laboratory in Bratislava, a 2D model was developed using River2D software. The study specifically targeted the barbel and bream fish zones, which have the most stringent criteria for depth and velocity. The simulation model developed demonstrated a strong predictive capability, with the Mean Square Error root ranging from 0.147 to 0.177, and the Mean Absolute Error ranging from 0.125 to 0.155, depending on the fish zone. A comparison of the results obtained (the velocity field and depths) indicates that the 2D model is a reliable tool for future modifications of this type of fish pass, whether for adjustments in its geometry or subsidizing discharges into the fish pass. Additionally, the visualization of the simulated velocity field, which is a critical factor for upstream migration, can aid in identifying migration routes.

Abstract This article examines the distribution of the indoor air temperature in a two-level underground parking garage in an administrative building located in a densely populated urban area of Bratislava, Slovakia. To analyze the temperature trends, continuous monitoring of the indoor and outdoor air temperatures was conducted using a mini datalogger from 2nd October 2023 to 4th February 2024. Through utilization of the EnergyPlus simulation engine, DesignBuilder software was used for dynamic simulation of the underground parking garage. The zonal model of the parking garage was calibrated using the actual indoor air temperature data measured. The heat gain from an average car in the first hour was approximately 1750 W during an exponential decline. Six simulations with different mechanical ventilation operating states were performed. The simulation results indicate that the average air temperatures in the zones were highest in a hygienic ventilation (HYG) simulation in a parking garage with gates. The lowest air temperatures were recorded in a maximum ventilation (MAX) simulation with holes instead of gates.

Abstract Objective evaluations of ceiling constructions are becoming increasingly significant due to advancements in the construction industry and rising resident complaints, particularly those concerning disturbances from low-frequency noise (<100 Hz). It is important to determine the required values for the maximum impact noise level in residential buildings. While the standard outlines a procedure for determining this level, there are no specific requirements for ceiling constructions related to heavy excitation sources. This study compares four different approaches for rating noise levels in the frequency range of 50 to 630Hz based on LA,Fmax. Through a numerical case study, the research reveals a linear deviation in the ISO-defined procedures based on a room’s volume and reverberation time, while also highlighting the differences in the outcomes of the evaluation between the four methods due to their distinct reference curve approaches. The findings indicate that no single evaluation procedure has emerged as definitively more reliable, thereby emphasizing the need for further investigation into the perception of impact noise and the establishment of standardized requirements.

Abstract 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.

Abstract 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.

Abstract 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.