ABSTRACT. Tensegrity structures are self-equilibrated spatial systems composed of pre-stressed pin-jointed compression and tension members. A tensegrity family is defined as a group of tensegrity structures sharing a common connectivity pattern. Two examples are the Octahedron and the X-Octahedron families, whose members are composed of rhombic and X-rhombic cells, respectively. In both families, the connectivity pattern consists of different levels of connectivity among three groups of cells. Since the struts in these families are grouped into three sets -each characterized by identical lengths and spatial orientations- their final equilibrium geometries can be effectively controlled. The expanded octahedron is the second member of the Octahedron family. It is a classified as a super-stable structure, meaning that its stability is maintained regardless of the prestress level or the specific material properties of its elements. This paper investigates the mechanical behavior of the expanded octahedron to evaluate its feasibility as a fundamental unit in modular construction. Full-scale tests, integrated with finite element (FE) simulations, have been conducted on several specimens with different pre-stress levels. This work presents the results of an initial structural analysis using a simplified finite-element model developed in ANSYS, which shows reasonable agreement with preliminary experimental data. For the configuration and loading case considered, the numerical approach demonstrates that the module exhibits a very high strength-to-weight ratio and tension–compression symmetry. Furthermore, while the global structural response remains essentially the same under tensile and compressive loading, the cables most heavily loaded when the module is tensioned are lightly loaded when the module is under compression, and vice versa, with the force magnitudes remaining virtually identical.

ABSTRACT. Steel lattice columns as extremely slender constructions (engineering complex objects), due to specific geometrical and constructive characteristics, require special conditions in the stages of design, construction, proper and careful exploitation: regular and high-quality maintenance. Occasional extreme climatic exposures of these objects generate the appearance of internal limit voltage states, which can exceed all projected assumptions.Therefore, specific locational exposure implies a direct increase in technical requirements in the design phase, but also in all subsequent phases of their life cycle. On the other hand, their high material value and emphasized social importance, due to the fact that they ensure the functioning of infrastructure, energy and information systems, also implies their high treatment. Due to the fact that, as authors, we have significant experience in the design, professional supervision, construction and specialist inspections of these buildings, in this work we point out the relevant problems in the processes of design, construction, rehabilitation and reconstruction, as well as maintenance during exploitation, which determine the conditions of durability and longevity of these buildings. As a manager and member of the professional expert team that conducted an expert examination on the cause of the fall of the antenna mast on Bjelasica in 2021, we found a number of deficiencies related to the quality of the reconstruction and the way these complex structures are maintained. Through a specialist inspection of the main Montenegrin telecommunication towers, we concluded that the issues of regularity of inspections and the quality of professional supervision and maintenance are not given the prescribed attention. We have also established that the legal and technical regulation in this area is not of high quality and that it needs to be improved and refined.

ABSTRACT. Confined masonry (CM) represents an attractive and cost-effective solution for earthquake-resistant construction of low- to mid-rise buildings in earthquake-prone regions due to its superior performance compared unreinforced masonry buildings. This study numerically investigates the monotonic and cyclic in-plane response of a CM walls using 2D equivalent strut macro-models of different complexity, with particular emphasis on the evaluation of seismic force demands in reinforced concrete (RC) tie-columns. Numerical simulations are performed in the OpenSees framework and validated against results from a full-scale cyclic shear–compression test on CM wall specimens. The results indicate that single-strut models are capable of reproducing the global force–drift response of CM walls; however, they are not adequate for capturing stiffness degradation, pinching behavior, and seismic force demands in RC tie-columns. Conversely, the multi-strut macro-model achieves a closer match with the experimentally observed hysteretic response and allows for a more reliable prediction of axial forces, shear forces, and bending moments in RC tie-columns. Comparison with a previously validated 3D FEM micro-model further confirms the superior capability of the multi-strut approach in capturing internal force distributions. The study highlights the importance of advanced macro-modelling strategies for seismic design and assessment of CM walls. Further validation with additional improvements of the ESM model is recommended to ensure its practical applicability.

ABSTRACT. This paper presents the seismic design of bridges on the Kragujevac Bypass. The Kragujevac Bypass is a new dual-carriageway, 22-kilometers-long highway currently under construction in Serbia, comprising 13 bridges and 5 overpasses. The alignment is located in a seismically active region with a peak ground acceleration (PGA) of 0.2 g and includes bridge columns with heights up to 21 m, which significantly influence the seismic response of the structures. Bridge superstructures consist predominantly of precast prestressed concrete beams, while several bridges are designed as cast-in-place slab structures, with individual span lengths up to 36 m and total bridge lengths reaching 450 m. Due to the presence of potential seismic faults at several bridge locations, results from detailed geophysical investigations were incorporated to define soil characteristics, in addition to conventional geotechnical investigations. A limited ductile behavior was adopted in the structural analysis, using a behavior factor equal to 1.5, in order to control damage and ensure predictable structural performance. The six largest bridges, with a total length exceeding 1845 m, were equipped with seismic isolation systems using low-damping elastomeric bearings. The application of seismic isolation resulted in a significant reduction of seismic demand in the substructures, particularly in bridge piers and foundations, while allowing controlled displacements at the bearing level. The structural design of the bridges was performed using a parametric approach, enabling automated generation of finite element analysis (FEA) models and execution of structural analyses. This approach allowed engineers to reduce modeling effort and shift their focus from technical implementation details in FEA software toward higher-level conceptual design decisions and evaluation of seismic performance.

ABSTRACT. Seismic site response and soil liquefaction are among the main factors controlling earthquake-induced damage in cities founded on young alluvial deposits. Rasht city, located in northern Iran near the Caspian Sea, is characterized by soft soil layers, shallow groundwater conditions, and significant variability in soil properties, which make it particularly vulnerable to seismic amplification and liquefaction phenomena. Accurate estimation of site-specific ground motion parameters is therefore essential for reliable liquefaction assessment.

This study presents an integrated evaluation of seismic site response and liquefaction potential for Rasht city, with a particular focus on Zone 2 selected as a representative case study. One-dimensional equivalent-linear site response analyses were performed using DEEPSOIL to estimate surface peak ground acceleration (PGA) values for a set of 11 selected earthquake records in two horizontal direction. The computed PGA values were subsequently employed as input parameters in simplified liquefaction evaluation procedures to calculate the factor of safety against liquefaction at different depths.

Liquefaction susceptibility was quantified using the Liquefaction Potential Index (LPI), obtained by integrating the depth-dependent liquefaction severity over the soil profile. The results for Zone 2 illustrate the strong influence of site-specific seismic response on liquefaction potential and highlight the importance of coupling site response analysis with simplified liquefaction methods. The findings of this study demonstrate how detailed analysis of a representative zone can provide valuable insight into liquefaction hazard assessment in urban areas with complex soil conditions.

ABSTRACT. The paper provides a concise analysis of selected references on the design of reinforced-concrete retaining walls, as well as the documents regulating this field. The mechanisms of failure of retaining structures are described, together with their connection to the causes of their occurrence. Particular attention is given to failures caused by overturning, sliding, and bearing capacity due to exceeding the soil’s shear strength, rotational resistance, and bearing capacity. The aspects of optimisation in selecting a retaining structure, as well as geotechnical robustness, are also discussed. Since seismic earth pressures on retaining structures differ significantly from active/passive, and at-rest pressures (where the diagram has its maximum ordinate at the base) while seismic pressure increases towards the top following a curvilinear distribution, this is of particular importance for structures in seismically active areas. For that reason, emphasis is placed on reviewing the literature related to theoretical and experimental results concerning seismic pressures on retaining walls, with the aim of clarifying the key mechanisms that govern their behaviour. Furthermore, when analysing the governing documents, special attention is given to the Eurocodes regulating this area. As current design practice still relies on the first-generation Eurocodes from the 1990s, the provisions of Eurocode 8 – Part 5: 2004 and EN 1997 – Geotechnical Design: 2004 (Part 3: Geotechnical Structures, Section 7) (first generation) are presented, as well as those from the second generation adopted in 2024. The focus is placed on the analysis of reinforced-concrete retaining walls, particularly in relation to their seismic response and the reliability of the adopted design assumptions. The methodology for analysing seismic pressures according to various proposed approaches is described in detail, particularly according to the 2004 Eurocode and the second-generation proposal from 2024, highlighting the differences and improvements introduced in the updated standards.

ABSTRACT. The Ibarac tunnel was excavated as part of the Rožaje bypass project in Montenegro. Nearly half of the excavation was carried out in glaciofluvial sediments, consisting of brown sandy clay with gravel and rock fragments. During construction, several collapses occurred within these materials. Ground pressures caused excessive deformation of the installed primary support, necessitating the reprofiling of several tunnel sections. A major collapse occurred within a section containing a parking niche at km 0+473. Although the overburden at this location exceeded 100 m, deformations reached the surface, forming a vertical channel with a diameter of 26m at the surface. Consequently, construction was suspended due to the high costs associated with remediating of this collapse. While these sediments remain stable immediately after excavation allowing installation of primary support, seasonally high groundwater levels encourage the intensive leaching of fine soil particles, which compromises the stability of the excavation. This paper proposes a rehabilitation solution for the major collapse in the Ibarac tunnel using pre-grouting technique. This method is often used to mitigate groundwater seepage and improve soil conditions. In glaciofluvial sediments, it is critical to limit groundwater pressures to prevent further migration of fines particles. Intensive leaching disrupts the soil skeleton, preventing the formation of a stable load bearing arch around the tunnel.

ABSTRACT. This paper describes an integrated procedure for micropile underpinning for foundation repair and seismic retrofit of existing buildings. Micropiles are small-diameter, drilled-and-grouted deep foundation elements, constructed as a composite element capable of carrying significant axial and moderate lateral loads. The installation process causes minimal disturbance, with low vibration and noise, making micropiles particularly suitable for underpinning existing structures with restricted access or low headroom. Unlike conventional piles, micropiles rely primarily on high-strength steel elements occupying up to half of the drillhole cross-section, with loads transferred from the steel through grout to the surrounding ground via friction along the grout-ground interface. Regarding regulatory frameworks, micropile design is governed by different standards in Europe and North America. Both are based on limit-state philosophy but differ in the specificity of guidance. In the United States, the FHWA micropile manual provides comprehensive procedures, including classification systems, empirical correlations for bond strength, and detailed verification procedures. By contrast, European standards do not provide standalone micropile codes; instead, micropiles are treated as specialized piles within Eurocode 7, requiring practitioners to synthesize guidance from multiple standards. Against this backdrop, this paper presents an effort to harmonize FHWA methodologies with Eurocode 7 partial safety factor philosophy through its implementation in a practical case study: the seismic retrofit and underpinning of an existing student dormitory.

ABSTRACT. The construction industry today faces increasing project complexity, a growing number of stakeholders, sustainability demands, and the digitalization of processes. Traditional management methods are often insufficient to ensure efficiency, reduce costs, and minimize delays. Building Information Modeling (BIM) represents a digital framework that integrates all aspects of design, construction, and maintenance of buildings. Through BIM, all project participants have access to a single, up-to-date model, enabling coordination, timely error detection, and resource optimization. This study aims to analyze the role of BIM in optimizing costs and time across various types of construction projects, with particular attention to challenges and implementation strategies in developing countries. A mixed-methods approach was applied, including a systematic literature review (2023–2025), quantitative analysis of 25 projects using BIM and traditional methods, and qualitative interviews with 15 BIM managers and project engineers. Quantitative data analysis indicates an average cost reduction of 12–18% and a project duration reduction of 15–22% for BIM-enabled projects. Results also show a 35–40% reduction in design errors, improved team coordination, and optimized material usage. Qualitative data reveal that key factors for successful BIM implementation include management support, staff training, process standardization, and gradual integration of BIM into critical project phases. Special emphasis is placed on integrating BIM with Digital Twin technology, artificial intelligence (AI), and IoT solutions, enabling real-time project monitoring, predictive maintenance, and additional optimization of costs and resources. The study concludes that BIM is not merely a digitalization tool but a key factor in achieving sustainable, efficient, and predictable construction projects. This paper provides detailed practical guidelines and strategic recommendations for companies, project managers, and regulators, aiming to maximize the benefits of BIM and its integration with advanced digital technologies in modern construction projects.

ABSTRACT. When designing structural concrete elements, long-term structural deformation due to shrinkage and creep must be considered. The incorporation of recycled concrete aggregate (RCA) into concrete increases both shrinkage and creep. RCAs are the highest quality recycled aggregates as they are the closest to natural aggregates. However, the use of RCAs is always associated with greater fluctuations in quality and usually with a deterioration in workability, mechanical properties, and long-term performance. The use of RCA in self-compacting concrete (SCC), where the proportion of aggregate is lower than in conventional concrete, is one way of mitigating the effects of RCAs. In this paper, experimental results of concrete creep measured on SCC with RCA are compared with the predictions of three widely accepted models for the prediction of creep strain in concrete, namely the ACI model given by the American Concrete Institute, the B3 model proposed by Bazant and Baweja, and the Eurocode 2 (EC2) model as proposed in EN 1992-1-1:2023. A comparison of predicted and measured creep is presented for three SCC mixes: one made entirely with crushed natural aggregates, one in which one coarse aggregate fraction is replaced by RCA, and one mix in which all coarse aggregates are replaced with RCA. It was found that the greatest difference between predicted and measured values exists for the mix made entirely with coarse RCA. For this case, all models underestimate creep strain, and the error of estimate increases with concrete age. For mixes made with natural aggregates and with one fraction replaced by RCA, the ACI and B3 models gave better estimates than the EC2 model, even though the EC2 model is the only one that explicitly takes into account the impact of recycled aggregate on creep strain.

ABSTRACT. The central weir of the Čunovo Water Structure represents a key hydraulic component of the Gabčíkovo – Nagymaros Waterworks, regulating discharges into the original Danube riverbed and conveying flood flows through the system. The structure is equipped with three radial gates combined with flap mechanisms, designed under the assumption of favourable downstream outflow conditions, ensuring adequate discharge capacity. However, long-term morphological changes, including significant gravel sedimentation and extensive growth of aquatic vegetation, have progressively deteriorated these conditions. As a result, the discharge capacity of the weir has been reduced, leading to elevated downstream water levels and operational constraints. To assess the impact of altered downstream conditions on the hydraulic performance of the weir, experiments were conducted using a physical scale model with a geometric scale of 1:75. Flood discharges were investigated for downstream water levels ranging from 128.0 m to 131.0 m. The results indicate a pronounced dependence of discharge capacity on downstream water levels, with maximum flows decreasing from approximately 3900 m³·s-1 to 1200 m³·s-1 as tailwater levels increased. These findings highlight the importance of downstream channel conditions for weir efficiency. The study underscores the need for continuous riverbed maintenance and targeted interventions to restore favourable outflow conditions. Future research will focus on riverbed management measures to improve hydraulic performance.

ABSTRACT. Weibull’s distribution is considered as very useful for determining the probability of events in different domains of human activity. One among different applications is in the determination of wind speed probability density function. The main issue in determining the Weibull probability distribution function (PDF) is determination of its coefficients of shape and scale from the empirical data. There are several different models for coefficients the scale and shape determination, such as method of moments and maximal likelihood (MLE) method to mention only those two among the others developed for theoretical and practical application. Consequently, it is possible to state that there is no unique and absolutely accurate model for determination scale and shape of Weibull probability distribution function. This fact opened a question about differences in Weibull probability distribution functions between models applied. In this research authors have designed the simulation model of Weibull PDF adopting true values for scale and shape coefficients and after that the coefficients were determined by moment and MLE method. Further development of the research was provided by utilizing simple iterative and Newton-Raphson methods for determining the scale and shape coefficients of Weibull PDF. After that the least squares method was applied and results were analyzed. The least squares method is the only method which provides the base for further statistical analysis of the differences obtained. The analysis encompassed the PDFs obtained by different methods, their differences and discussion of obtained results.

ABSTRACT. The paper presents a method of repairing specific foundations of a historical bridge that provides base isolation for seismic effects. Namely, several bridges from the Turkish period in Bosnia and Herzegovina were found to be based on multiple layers of cross-placed wooden beams with stone infill. Previous papers have shown that this type of foundation acts as a seismic base isolation, and therefore it is very important to maintain these properties during any repairs. This is illustrated by the example of a bridge over the Neretva River in Glavatičevo, Konjic Municipality, where a rehabilitation project was necessary due to the subsidence of the foundations. This type of damage is common in old bridges with massive central pillars and intense river flows, especially considering the age of the bridges. Erosion and deepening of the river bed can have disastrous consequences for bridges with this type of foundation, as material from under the foundation is washed away, but also wooden beams deteriorate, since they are alternately exposed to water and air. Therefore, the repair method must strengthen the river bed while simultaneously increasing the water level, but without stiffening the foundations themselves, which must remain flexible to prevent the transfer of seismic forces to the bridge. Such requirements are often contradictory to current river bridge foundation practices, which may lead engineers to choose the wrong repair method. With this in mind, the best principle when rehabilitating any historical structures, especially bridges, is to restore the structure to its original condition, in which it survived all those years before.

ABSTRACT. This paper presents the development of a standardized bridge inventory and a screening-based framework for preliminary seismic hazard assessment along the Bar–Ulcinj road section in Montenegro. The main objective is to provide a systematic overview of bridge characteristics and their exposure to seismic action at the network level. A comprehensive field survey was conducted for all bridges along the investigated road section, complemented by a review of available technical documentation. Based on the collected data, a geospatial bridge inventory was developed in a GIS environment, incorporating key geometric, structural and condition-related attributes and enabling typological classification of bridges. The analysed bridge stock consists of reinforced concrete road bridges with different structural systems and geometric characteristics. Using the inventory data, bridges were grouped into representative typological classes relevant for preliminary seismic assessment. Seismic hazard was characterised using the European Seismic Hazard Model ESHM 2020. Peak ground acceleration (PGA) values were extracted for each bridge location and adjusted using dynamic amplification factors to account for local soil conditions, resulting in effective seismic acceleration values. These values were used to identify spatial variations of seismic hazard along the road section. Based on the defined seismic hazard levels and basic indicators of bridge condition and geometry, a preliminary prioritisation of bridges was performed. The results identify bridges exposed to higher seismic demand and unfavourable site conditions, providing a transparent basis for selecting structures that require more detailed seismic assessment. The study demonstrates that a GIS-based bridge inventory combined with seismic hazard screening represents an efficient tool for supporting decision-making and seismic risk management of road transportation infrastructure.

ABSTRACT. Infrastructure systems in the Western Balkans are increasingly exposed to climate-related hazards, including floods, droughts, and extreme weather events, which challenge the long-term resilience of critical assets such as hydropower plant facilities. In this context, Nature-Based Solutions (NbS) are gaining attention as complementary approaches to conventional grey infrastructure, offering adaptive, cost-effective, and environmentally sustainable options. Despite growing interest in NbS, their systematic integration into infrastructure planning at regional level remains limited, particularly in the context of large-scale and legacy infrastructure systems. In addition, fragmented planning practices and limited institutional capacities pose further challenges to their wider adoption. This paper explores a regional approach to integrating NbS into planning for infrastructure resilience, highlighting the conceptual framework, methodological setup, and the status of ongoing activities. The approach focuses on multi-scale assessment, engaging stakeholders, and aligning NbS with existing infrastructure management practices. Special attention is given to how NbS can enhance the resilience of hydropower plant infrastructure and its associated operational components—such as spillways, intake tunnels, service roads, and auxiliary buildings—through ecosystem-based measures that contribute to risk reduction and climate adaptation. Since the activities are still in progress, the paper outlines key challenges, shares preliminary observations, and reflects on potential contributions to regional cooperation and knowledge exchange. Overall, the proposed framework is intended to guide decision-makers and practitioners in gradually incorporating Nature-Based Solutions into infrastructure resilience strategies across the region.

ABSTRACT. This paper presents the results of nonlinear static (pushover) analyses of a 15-story reinforced concrete (RC) coupled wall system building designed according to the second generation of Eurocode 8. The structure consists of core walls interconnected by coupling beams and perimeter columns connected to the walls through the floor slabs. The objective is to explore the global response of the building, the development of internal forces in the core walls, and verify whether the sequence of damage development in the structure is consistent with the design assumptions. The building was represented by a three-dimensional model developed in OpenSees. Pushover analyses were performed independently in the X and Y directions. In the X direction, upon reaching the building’s maximum strength, the overturning moment is equally resisted by frame action through coupling beams and flexural resistance of the walls and columns, whereas in the Y direction, 75% of the overturning moment is resisted through frame action and the remaining 25% through flexural resistance of the walls and columns. The design base shear was approximately 12% of the building's weight, while pushover analysis showed an ultimate capacity of about 24% in both directions. The variation of axial force in some walls led to a higher-than-expected flexural capacity. The damage analysis shows that coupling beams are the first elements to reach the near-collapse (NC) limit state, while columns and walls remain essentially elastic at this stage. The walls reach the NC limit state only after the failure of most coupling beams.

ABSTRACT. The goal of the contribution is to review the possibilities of flood protection of the county City Trebišov against the flood situation that can occur on the Trnávka River flowing along the City. The analysis was performed by mathematical modelling using HEC-RAS software. Based on Trnávka drainage basin reconnaissance, own measurements in situ, and study literature relating thereto, a proposal of several technical measures for safe run-off in the Trnávka River bed has been elaborated and consequently evaluated from a hydraulic point of view. Mitigation of flood discharges was ensured through lateral spillway structures that directed the excessive water flow towards the existing drainage system connected with the Hraň pumping station into the Ondava River. The presented contribution includes the evaluation of the flood situation in 2010 and recommendations for the mitigation of the flood wave. The whole research is a part of nature-based solutions for climate change adaptation in frame of the EU-financed LIFE Strategic Nature and Integrated Projects in Slovakia.

ABSTRACT. Hydropower plants are an important energy source in the electric power system of Slovakia. They are used primarily to cover variable load. They provide a contingency reserve for the system and ensure the balance of the energy supply system by providing so-called ancillary services. The scheduling and operational control of hydropower plants under normal flow conditions is carried out by the dispatch centre of Slovenské elektrárne. From a mathematical point of view, the effective load allocation among individual hydropower plants is a complex optimization problem that can be solved using methods from the field of optimal control theory. The paper describes the currently used method for operation planning of this hydropower plant system by means of a software tool called Hydromodel. This tool is used to model the hydraulic relationships and linkages between individual hydropower plants in the system and to optimally allocate the load demand to the individual elements of the system so that the entire power system operates at minimum cost.

ABSTRACT. Veľká Domaša water structure (WS) was built on the Ondava River in 1967. The hydrological analysis aimed to determine the minimum residual discharge released from the reservoir in a given period of the year. The most important aspect was to ensure a sufficient discharge in the Ondava River under the Veľká Domaša WS from a qualitative and quantitative point of view, as well as guarantee appropriate water level conditions in the reservoir to fulfill all necessary functions from a recreational, flood protection, and hydropower utilization point of view. According to that, all essential hydrological data were provided by the operator - Slovak Water Management Enterprise (SWME) as well as measurement results of chosen qualitative markers in different profiles of the Ondava River reaching from the WS profile (rkm 91.400) down to the Brehov profile (rkm 4.200). These data were replenished by the list of registered contamination sources of the Ondava River (BUKOCEL Hencovce, TP2 – Chemko Strážske, all communal sewage treatment plants) downstream to the confluence with the Topľa River. The reason for changing the handling order was the requirement for a sufficient water level regime in the reservoir of the Veľká Domaša WS for other purposes. The analysis results led to proper changes in handling order of the Veľká Domaša WS.

ABSTRACT. The catchment area of the Niksicko polje, within which the HPP Perucica hydropower system is located, is characterized by highly complex hydrological and hydrogeological conditions resulting from the dominant karst terrain. Reliable monitoring of hydrological and meteorological processes in such an environment represents a fundamental prerequisite for safe and efficient water resources management, as well as for the optimal operation of the hydropower plant. In this context, the hydrological and meteorological monitoring network of HPP Perucica plays a key role in collecting data necessary for water balance analysis, definition of the system’s operating regime, and improvement of water management models.This paper presents an overview of the development of the hydrological and meteorological monitoring network of HPP Perucica, with particular emphasis on the system status prior to modernization and on activities implemented within the Reconstruction and Modernization of HPP Perucica – Phase II project. The analysis of existing hydrological studies and previously available measurements indicated that the available data did not fully meet the requirements of modern water resources management, which necessitated the expansion and modernization of the monitoring system.The modernized system comprises a dense network of hydrological gauging stations, a piezometric network for groundwater monitoring, automatic meteorological stations, and precipitation stations, all equipped with modern measuring devices and remote data transmission. A special part of the paper is dedicated to the reconstruction of the Duklov Most hydrological station, which represents a key location for discharge measurement of the Zeta River and control of inflows into the HPP Perucica system. The applied technical solutions enable accurate and reliable measurements over a wide range of hydrological conditions. The results of the monitoring network modernization provide a reliable basis for improved hydrological analyses, development of hydrological–hydraulic models, and long-term optimization of HPP Perucica operation.

ABSTRACT. Bus rapid transit (BRT) is a transport system based on bus passenger transport that provides fast, convenient and cost-effective mobility services. These benefits are achieved through traffic lanes intended exclusively for buses, fast and highly frequent services. Therefore, a homogeneous system, such as BRT, which includes facilities, services and benefits and has the potential to become an alternative that is far more competitive than unsustainable car-oriented mobility (which is a major source of socioeconomic inequality and climate change impacts around the world), can redefine the city's transport identity itself, especially in cities of less developed countries, such as Montenegro. Modern problems associated with a disproportionate increase in individual motorization in relation to population growth, coupled with inadequate public transport services, make life in cities more difficult. In addition to traffic jams caused not only by increased use of cars, but also by the lack of parking space, environmental impact is also a parameter that should not be avoided and ignored when trying to solve ongoing challenges. Lack of interest in alternative modes of transport is one of the main negative effects that have prevailed in recent decades, especially in cities of less developed countries, such as Montenegro. Podgorica, as the capital, represents the center towards which not only the surrounding, but also other cities in the country gravitate towards. Traffic on all sections of infrastructure corridors within the city is below the required level of service during peak hours, but also outside of them. Among other things, one of the possible alternative solutions that would implement a larger transport capacity, with low (to medium) investment costs, is a modern way of urban passenger transport whose importance is growing globally – the already mentioned fast bus transport.

ABSTRACT. In recent decades, there has been a growing global trend in the research and application of recycled materials in pavement structures with the addition of various alternative materials. The aim of this study is to provide a theoretical justification, through a comparative analysis of the disadvantages and advantages of the observed pavement structures, from the perspective of pavement life-cycle costs, as well as to assess their environmental impact throughout the pavement life cycle. The analysis was conducted using the LCA software PaLATE. A total of eight TYPE3 pavement structures of different compositions were analyzed and grouped into four pairs, in which the economic and environmental impact values of structures without and with alternative materials—used as full or partial replacements, as well as with or without additives—were compared. The mixtures were prepared using the warm mix asphalt (WMA) process, while the following alternative materials were used: RAP (Recycled Asphalt Pavement), RCA (Recycled Concrete Aggregate), C&DW (Construction and Demolition Waste), SS (slag from the steel production process in power plants), polymer lignin, cobalt catalyst, biodegradable materials, and fly ash. The advantages of modern treatments in both the design and construction, as well as the maintenance of pavement structures, represent alternative options for the “greening” of existing pavements, with the aim of approaching the, for now seemingly unattainable, sustainability of pavement structures. The concluding remarks provide a detailed overview of the comparative analysis, clearly indicating the advantages of modern treatments in terms of both economic and environmental impacts on pavement construction and maintenance.

ABSTRACT. This study examines the linear relationship between the Rock Mass Rating (RMR) and anchor density (m/m') in 10 railway tunnels on the Kichevo – Lin section, part of the Pan-European Transport Corridor VIII in Macedonia. Using Pearson correlation analysis on data obtained from the tunnels, the following results were achieved: average RMR = 24.5 (corresponding to Class IV – poor rock mass according to Bieniawski), average anchor density = 31.6 anchors/m, with a Pearson coefficient r = 0.196 (p = 0.588). This coefficient indicates a very weak positive linear correlation (|r| < 0.3 according to Cohen), with an explained variance of only 3.85% and a statistically insignificant relationship (the null hypothesis of no correlation is not rejected). Although the average low RMR logically corresponds to a high need for support, the results show that RMR is not a strong linear predictor for anchor density due to high variability caused by local geological factors (faults, hydrology). The study concludes that RMR should be used as an initial screening tool, supplemented by other systems (such as the Q-system), local modifiers, and multiple regression for precise support design in complex conditions. This opens possibilities for the development of a hybrid predictive model adapted to the local geology of Corridor VIII.

ABSTRACT. The selection of the most optimal highway section variant is a complex process that involves analyzing multiple criteria to ensure the most rational and objective decision-making. This study examines the application of multi-criteria decision-making (MCDM) methods using various evaluation criteria to eliminate subjectivity in the selection process. Three MCDM methods were applied—Weighted Sum Method (WSM), Analytic Hierarchy Process (AHP), and the VIKOR method—on three proposed alternatives for the Prilep–Bitola highway section. The evaluation considered five key criteria: construction investment costs, operational and maintenance costs, technical feasibility, construction duration, and environmental impact. According to the results, Alternative 2 (Green) achieved the best performance across all methods, with the highest score of 0.919 in WSM, the top priority value of 0.46 in AHP, and consistent first-place ranking across all VIKOR scenarios. These consistent outcomes confirm the reliability and robustness of multi-criteria analysis in infrastructure planning. The study contributes a transparent, replicable framework that supports strategic decision-making in the selection of highway corridors, and highlights the importance of balancing economic, technical, and environmental objectives in transportation infrastructure design.

ABSTRACT. Remote sensing represents a key source of spatial data due to its capability to provide large-scale and non-invasive observations of the Earth’s surface. The growing availability of satellite imagery with different spatial resolutions has increased the need for advanced image processing methods that enable efficient extraction of meaningful information. Image segmentation and classification are essential steps in satellite image analysis, as they support the identification of land cover types and spatial objects relevant to urban planning, environmental monitoring, and land management. This paper investigates the applicability of the Segment Anything Model (SAM) for satellite image segmentation across multiple spatial resolutions. The study uses Sentinel-2, WorldView-3, and PlanetScope imagery over the urban area of Novi Sad, Serbia. The segmentation results obtained with SAM are subsequently used for land cover classification employing the Support Vector Machine (SVM) algorithm. Segmentation quality was evaluated using over-segmentation and under-segmentation indicators, while classification performance was assessed based on overall classification accuracy. The results indicate statistically and structurally significant differences in segmentation behavior among datasets with varying spatial resolutions, with very high-resolution WorldView-3 imagery producing a larger number of segments and pronounced over-segmentation. The integration of SAM-based segmentation with SVM classification confirms the feasibility of integrating foundation models within an object-based remote sensing framework, while also highlighting the influence of spatial resolution on segmentation structure and classification accuracy.

ABSTRACT. The establishment of an appropriate geodetic control network is a prerequisite for the construction and safety of tunnel structures. This paper presents the design and validation of a hybrid geodetic network for the “Ošlji rit” tunnel, located in the forested and hard-to-access terrain of the Brajčin laz locality (Čemerno). Due to significant GNSS signal degradation caused by dense forest cover, a hybrid approach was adopted, integrating extended static GNSS observations with local terrestrial micro-triangulation. The geodetic network is stabilized by concrete pillars equipped with plates for forced centering. Statistical validation using the F-test (F = 1.07) confirms the high internal homogeneity of the network and its consistency with the national reference framework. The applied methodology demonstrates that the integration of different geodetic techniques effectively overcomes the limitations of complex terrain, providing a reliable reference framework for precise tunnel breakthrough.

ABSTRACT. The reconstruction of railway infrastructure in Serbia, particularly within the Belgrade railway junction and the Pančevo corridor, required the establishment of a harmonized geodetic framework to ensure spatial integrity across multiple projects. A geodetic reference network (GRN) was defined using GNSS static positioning for surface points and terrestrial surveying for tunnel environments, complemented by geometric levelling for vertical control. Transformation into the national Gauss–Krüger projection was achieved through Helmert similarity transformation, minimizing deviations relative to adjacent projects. Survey campaigns combined GNSS, total station observations, and LiDAR technology (Amberg GRP5000 system), enabling efficient data collection under restricted access conditions. Results confirmed high positional accuracy, with horizontal deviations within 1 cm and vertical consistency across the Danube River verified by GNSS levelling. The study demonstrates the importance of integrating modern surveying technologies with legacy projection requirements, providing a methodological reference for future railway reconstruction projects in complex urban environments.

ABSTRACT. Scan-to-BIM represents a modern approach for the digital reconstruction of buildings and environments, based on the integration of spatial data acquisition technologies and Building Information Modeling (BIM) methodologies. By combining data captured through laser scanning, photogrammetry, and drone imaging with BIM modeling environments, Scan-to-BIM enables the creation of accurate, structured, and information-rich digital representations of real-world objects. This approach plays an increasingly important role in architectural documentation, renovation projects, facility management, and digital heritage preservation. This paper presents a Scan-to-BIM methodology applied within a real case study context. UAV-based photogrammetric data were used to generate a dense point cloud representation of the object, which served as the primary reference for BIM modeling. Modeling was performed directly within the point cloud environment, enabling precise interpretation of spatial geometry and architectural structure. The process integrates spatial data acquisition, point cloud-based modeling, and structured BIM documentation, resulting in a final digital report that includes architectural drawings, 3D views, sections, elevations, and visualizations. The presented methodology demonstrates the reliability of Scan-to-BIM for accurate digital modeling and structured spatial documentation.

ABSTRACT. In controlling a vertical tower (pillar, pole, tower) a ubiquitous problem of its straightness arises simultaneously. In the paper a method for analyze the geometry and verticality of the tower under consideration PERGANALTOWER METHOD proposed by the present author is the subject. At first by measuring the coordinates of tower axis points were determined. For the purpose of examining tower straightness a special method is applied. It comprises the checking of tower axis straightness in two projections, in the horizontal plane and in the characteristic vertical one passing through the axis projection in the horizontal plane. If after the testing the axis straightness is accepted in both projections, in the horizontal and characteristic vertical planes, then the definitive conclusion in favour of tower axis straightness is made. For the purpose of testing the tower axis verticality the axis projection onto the characteristic vertical plane, already defined, is used. In this testing two approaches are used: Approach I – tower axis points belong to the same vertical and Approach II – tower axis slope angle does not exist. In the first approach the geometry axiom according to which tower axis points will belong to the same vertical if the tower is vertical is used. In the second approach the geometry axiom according to which the slope angle of a straight line is zero if it is vertical is used. In approach I the congruence of tower axis points positions in projection onto the horizontal plane is tested. In approach II the axis slope angle in the characteristic vertical plane is tested. In PERGANALTOWER METHOD for tower verticality testing the power of the tests is expressed. The test in approach II has been found to be the most powerful, therefore it is specially recommended for application.

ABSTRACT. The growing maturity of Artificial Intelligence (AI) techniques alongside the widespread adoption of Building Information Modeling (BIM) presents significant opportunities to augment architectural design with data-driven intelligence. While existing research has explored individual applications of AI or BIM, their systematic integration within architectural design workflows remains fragmented. This paper presents an integrative literature review examining how AI can be embedded within BIM-centric processes to support generative design, performance prediction, constructability analysis, and lifecycle-oriented decision-making. Drawing on peer-reviewed studies from architecture, construction engineering, and computer science, the review synthesizes current research into a layered conceptual framework linking BIM data structures, interoperability standards, and AI-enabled decision-support mechanisms. Key application domains identified include AI-driven generative design, accelerated building performance estimation, enhanced clash detection, and lifecycle cost and sustainability analytics. The analysis highlights recurring benefits, such as expanded early-stage design exploration and improved alignment between design intent and performance outcomes, while also identifying persistent challenges related to data quality, semantic interoperability, explainability, governance, and professional accountability. The findings suggest that AI–BIM integration has strong potential to enhance architectural decision-making across design stages, particularly in early-phase exploration and lifecycle assessment. However, the literature reveals notable gaps, including limited empirical validation in real-world projects and the absence of standardized evaluation benchmarks. This paper provides a structured foundation for future empirical research and offers guidance for the responsible adoption of AI-enabled BIM workflows in architectural practice.

ABSTRACT. This paper examines rhythm in architecture, with particular emphasis on the concept of irregular or random rhythm, understood as a rhythm whose process of generation or determination includes a component of randomness. The specificity of such rhythm lies in its association with what is perceived as natural, as identified through psychological research. Different modes of manifestation of this type of rhythm in architectural and urban compositions are identified. As irregular rhythm has become increasingly present in contemporary architectural practice, the paper also explores the ways in which it can be generated. The paper distinguishes three types of irregular or random rhythm: (1) spontaneously formed rhythm (developing over time through accumulation from generation to generation), (2) natural rhythm, and (3) fractal rhythm. With regard to their generative potential, the first type can only be imitated to a certain extent—an approach some authors describe as naive and superficial imitation of a finished form. The second type can be directly or indirectly adopted from the natural environment through measurement and control devices, that is, from the rhythms of change in natural factors. The third type can be generated using objects of fractal geometry from the class of random fractals, viewed as mathematical models of natural rhythms of change or natural distributions of elements. This possibility was initially proposed by Carl Bovill, who designated rhythm determined in this way as fractal rhythm. Two types of fractal objects are considered: fractional Brownian functions and random curds. Fractional Brownian functions can be obtained either by generation using appropriate computer programs or directly from the natural environment by recording changes in the values of certain natural variables. In the case of random curds, instead of adopting pre-existing fractal objects, they can be generated using the mathematical method of curdling.

ABSTRACT. Cost management represents one of the most critical, but also the most problematic aspects of managing transport infrastructure projects, as confirmed by chronic budget overruns around the world. The aim of this paper is to identify the causes of this situation and propose a modern approach for improvement in the Republic of Serbia through a comparative analysis of foreign and domestic cost estimation practices. The research is based on a systematic review of the literature, a detailed analysis of international standards and a comparative study of the practice of developed countries. The results clearly indicate that innovative, modern approaches to the cost estimation of transport infrastructure projects achieve significantly better cost control. As a key contribution, the paper proposes an integrated approach for improving domestic practice, which includes: adoption of internationally recognized standards; development of national guidelines for cost estimation inspired by best practice; application of modern technologies such as integrated BIM (Building Information Modeling) and machine learning for decision support and cost forecasting; training experts and building a national database of previous projects and estimated costs. The conclusion of the paper points out that a precise cost estimate, especially in the early, conceptual phases of the project, is the foundation of successful implementation. The implementation of the proposed integrated approach would enable developing countries to overcome existing challenges, reduce the risk of budget overruns and improve the efficiency of managing strategically important transport infrastructure projects.

ABSTRACT. Accurate cost estimation for investment projects, particularly in the construction and transport infrastructure sectors, is essential for ensuring economic efficiency, financial stability, and long-term socio-economic development. Despite its importance, budget overruns remain a persistent and widespread challenge in large-scale infrastructure projects worldwide, occurring across different countries, project types, and stages of implementation. This paper examines the economic and managerial significance of accurate cost estimation during the early, conceptual phases of infrastructure projects, where key decisions with long-term financial consequences are made. The analysis is based on selected international case studies of major transport infrastructure projects, including the Big Dig (USA), London Crossrail (UK), the Channel Tunnel (UK/France), the Gotthard Base Tunnel (Switzerland), and the California High-Speed Rail (USA). These projects illustrate recurring patterns of cost overruns driven by unrealistic initial estimates, scope changes, technical and geological uncertainties, regulatory and political influences, and deficiencies in project management and risk control. Furthermore, the paper reviews international standards, guidelines, and best practices in cost estimation and cost management, emphasising the role of standardised methodologies, transparent procedures, and structured decision-making frameworks. The findings highlight that systematic and realistic early-stage cost estimation, supported by robust regulatory frameworks and continuous risk management, is critical for reducing budget overruns. The paper concludes that the consistent application of best practices in cost estimation and project governance is essential for improving project performance, optimising resource allocation, and maximising the economic and social benefits of public infrastructure investments.

ABSTRACT. The construction industry continues to struggle with schedule delays, cost overruns, labor shortages, and stricter expectations around sustainability and occupational safety. In response, many organizations have accelerated digitalization efforts, with AI increasingly being used alongside Building Information Modeling (BIM), computer vision, and data analytics to support decision-making and day-to-day project work. This paper has two objectives: (1) to briefly outline the main areas where AI is currently applied in construction, and (2) to compare four software tools that represent different stages of the project life cycle – Autodesk Forma (early-stage design and planning), OpenSpace (site documentation and progress tracking), PlanRadar (quality management, task handling, and documentation workflows), and Togal.AI (automated quantity takeoff for estimating and bidding). The comparison is based on consistent criteria: intended purpose and project phase, AI-supported features, input and data requirements, implementation effort, licensing and pricing approach, suitability for different company sizes, and key strengths and limitations. The findings suggest that these tools serve different needs rather than competing directly. Used together, they can support multiple phases of a project, from early planning to site execution and cost control. As a result, the “best” choice depends largely on what the organization is trying to improve, what resources it can commit, and how mature its internal processes already are. By connecting tool capabilities with common construction use cases, the analysis aims to help organizations make more grounded and practical selection decisions.

ABSTRACT. The design of seismically resistant pile-supported structures represents a highly complex engineering task, particularly with respect to the reliable assessment of the design seismic action. Such an assessment cannot be performed without a comprehensive analysis of the dynamic soil–pile–structure interaction (SPS interaction). Structural engineers in Montenegro are practically faced with this problem on a daily basis. At many locations along the Montenegrin coastal area, the engineering geological characteristics of soil are highly unfavourable, making pile foundation necessary for structures (buildings). Furthermore, it is well known that this region is characterized by very intense seismic activity and, consequently, by a high level of seismic hazard. Unfortunately, current national and international regulations do not yet sufficiently consider the seismic performance of pile-supported structures, nor do they provide guidance that fully satisfies the practical requirements of structural design engineers. Within the national scientific research project entitled “Seismic Loading of Structures Founded on Piles”, whose primary objective is to provide a more detailed assessment of seismic action and seismic resistance of pile-supported structures, the authors of this paper conducted an extensive investigation of the engineering geological characteristics of the ground along the Montenegrin coastal area. Based on this investigation, all zones for which it can be reliably concluded that the ground conditions require pile foundations, were identified and mapped. For each of zones, representative engineering geological ground cross sections were defined. Some of these sections will be presented in this paper. Accordingly, the main input data required for carried out dynamic SPS interaction analyses were compiled.

ABSTRACT. Except in cases where a structure is founded on very stiff and rigid soil (rock), a real response of structure to seismic excitation cannot be determined without considering its interaction with the foundation soil during the excitation (seismic soil–structure interaction, SSI). In other words, obtaining a real seismic response of a structure requires consideration of the foundation soil flexibility (deformability, real stiffness). Naturally, this is far from straightforward, as the mechanical behavior of soil as a natural material under dynamic shear loading, in drained and particularly in undrained conditions, is very complex and therefore extremely demanding in terms of mathematical formulation. The situation is further complicated in the case of pile-supported structures. The deformability and stiffness of the foundation soil are further affected by the presence of piles, especially when they are closely spaced. At the same time, the contact zones between the piles and the surrounding soil represent additional locations for potential seismic energy dissipation, along with the possible occurrence of plastic deformations in the soil around the piles, or the formation of plastic hinges in the piles themselves, which requires special caution. In this paper, two different approaches for the numerical analysis of the seismic response of pile-supported structures are presented. Both approaches consider soil–pile–structure interaction (SPS interaction) during the seismic excitation, in a more or less demanding and complex way. The direct numerical method and the substructure numerical method are analyzed in more detail, with a clear emphasis on their main advantages and disadvantages

ABSTRACT. Earthworks and subgrade construction constitute a major cost component in road engineering projects, necessitating the search for sustainable and cost-effective soil improvement methods. This study investigates a design-oriented approach to select consolidation loads for silty sand from the Odra proglacial valley, stabilized with cement and granodiorite dust recovered from aggregate processing. To align with circular economy principles and reduce the carbon footprint of traditional binders, two specific mixtures were evaluated: 4% cement (C4) and a composite of 2% cement and 2% mineral dust (C2+2). Cylindrical specimens were prepared and cured for 28 and 365 days in controlled moisture conditions to simulate field environments. Uniaxial compression tests were performed, and the instantaneous elastic stress–strain response was accurately described using a Power-Law model (PLM) fitted via the least-squares method. During the post-consolidation series, specimens underwent two loading cycles to target stress levels, focusing strictly on instantaneous deformations while excluding time-dependent creep. The findings demonstrate that consolidation triggers a favorable transformation in the material's behavior, shifting from a brittle response (n>1) to a significantly stiffer and more stable consolidated state (n<1). Predictive exponential relationships for PLM parameters were established with high statistical accuracy, generally exceeding R2=0.96. Remarkably, while the C4 mix is approximately 9.6% stiffer than the C2+2 mix, this small advantage requires double the amount of cement. These results confirm that a 50% reduction in cement content leads to only marginal performance loss, proving that granodiorite dust effectively complements the cementitious matrix while promoting environmental responsibility.

ABSTRACT. This study examines how the use of different interpretation methods affects the result when obtaining the ultimate capacity of a bored pile from load-settlement curves. A series of two-dimensional axisymmetric models were developed to simulate a single bored pile in cohesive soil strata. The primary variable in the parametric analysis is the soil stiffness modulus, which varied across a range representative of soft to very stiff cohesive soils. Results were obtained from numerical models with E1/E2 ratio variations ranging from 0.1 to 1, where E1 and E2 are stiffness modules of the top and bottom layer, respectively. This analysis focused on extracting load-settlement curves, ultimate bearing capacities and load-transfer mechanisms along the pile shaft and base. The mechanical characteristics of the soil were not altered, only the stiffness modulus of the layers varied to create the different profiles. For each of the six different stiffness ratios simulated, a load-settlement curve was generated. Six interpretation methods were used, Double-Tangent, Davisson, Brinch-Hansen, Chin-Kondner, Decourt and DeBeer. Among these methods, there are significant differences between the obtained capacities with the highest and lowest prediction differing by nearly 60% under certain soil profile conditions. The Brinch-Hansen and Decourt methods predict on average the highest capacities, while DeBeer estimates are the lowest. Differences between the predicted capacities narrow as the soil profile approaches a homogenous condition. The obtained results show that the calculated capacity depends significantly on which interpretation method is used.

ABSTRACT. Soft discontinuous rock masses pose significant challenges in engineering geology and geotechnics due to the complex interactions between the physical-mechanical properties of the rock and the geometry of discontinuities. Traditional laboratory tests predominantly use small samples, limiting the ability to replicate the natural fracture and layer structures, and consequently the monitoring of time-dependent deformations. This paper presents a unique experimental approach to investigating soft discontinuous rock masses, emphasizing the use of large samples that simulate the natural discontinuity geometry and allow the observation of shear and rheological behavior. A literature review shows that previous studies have not enabled the quantification of scaling effects, roughness, normal stress, and time-dependent phenomena in an experimental context. The author’s experiment addresses these gaps, providing an empirical basis for the development and validation of numerical models. The experiment is designed to combine improvised laboratory equipment with larger samples, enabling the study of phenomena that standard equipment cannot replicate. This approach has significant engineering applications, including the design of tunnels, slopes, retaining structures, foundations, and other geotechnical structures, and contributes to a better understanding of time-dependent deformations, shear strength, and layer-fracture interactions. Although the paper does not present specific results, it emphasizes the methodological and conceptual significance of large samples and improvised methods in experimental research, highlighting the innovation and uniqueness of the experimental approach compared to previous studies. The conclusion is that this approach enables higher-quality modeling, improved understanding of soft discontinuous rock masses, and provides a foundation for further experimental research and practical engineering applications.

ABSTRACT. Settlement of piles represents one of the key parameters in geotechnical design, as the accuracy of settlement prediction directly affects the safety, serviceability and long-term performance of foundations and structures. Therefore, understanding pile behaviour under axial loading and selecting appropriate settlement prediction methods are of fundamental importance in engineering practice.

This paper presents a comparative analysis of settlement prediction for a single vertically loaded bored pile using three commonly applied approaches: an analytical method according to Vesić, a numerical analysis based on the finite element method implemented in the software Phase2 (RS2), and an empirical approach based on cone penetration test (CPT) data using the software GEO5 – Pile CPT. The analyses were carried out for a selected geotechnical profile derived from CPT investigations and classified according to the Robertson soil behaviour type classification, under a working load of 1000 kN.

The numerical model was developed in an axisymmetric domain using an elastoplastic constitutive model with explicit modelling of the pile–soil interface, enabling a realistic representation of load transfer mechanisms. The numerical analysis resulted in a total pile head settlement of 11.7 mm, with 22% of the applied load transferred through the pile base and 78% through shaft resistance.

The CPT-based empirical method yielded a settlement value of 11.3 mm, showing good agreement with the numerical results. In contrast, the analytical method according to Vesić predicted a lower settlement of 7.9 mm due to simplified assumptions regarding soil behaviour and load transfer mechanisms.

The results indicate that numerical analysis and CPT-based methods provide mutually consistent settlement predictions for the analysed bored pile at the serviceability limit state, in accordance with the principles of Eurocode 7 and the NEN 6743 standard, while analytical approaches are mainly suitable for preliminary settlement assessment.

ABSTRACT. Smart and multifunctional concrete can be defined as an intelligent material with properties quite different from those of conventional concrete. The change in the properties of concrete can be obtained through a multitude of possibilities. Among such different possibilities the use of carbon-based materials such as carbon nanotubes, carbon fibers, graphene, carbon black, or combinations of these, has been used. Piezoresistive composite sensors offer a simple and low-cost approach for embedded stress monitoring in geotechnical and pavement systems; however, their performance under soil confinement and moisture exposure remains insufficiently documented. The aim of this paper is to present and discuss some results concerning the development of cement composites integrating carbon materials for traffic monitoring purposes. It investigates the sensing capacities of piezoresistive cement-based composites incorporating carbon black particles to develop embedded strain sensors for traffic monitoring applications. This study experimentally evaluates the electromechanical response of piezoresistive sensors embedded in compacted soil and subjected to controlled impact loading. Two sensors were installed at depths of 6 cm and 14 cm and monitored using an oscilloscope-based acquisition system. All functional sensors exhibited clear voltage transients associated with impact events, confirming preserved piezoresistive behavior. These results demonstrate the feasibility of piezoresistive composites for embedded soil and pavement monitoring applications.

ABSTRACT. Climate change is driven by greenhouse gas emissions, with the construction sector contributing significantly due to high energy consumption and CO₂ emissions. As most buildings and infrastructure that will be in use in Europe by 2050 already exist, achieving climate targets depends on improving their environmental performance and reducing embodied carbon. Evaluating such interventions requires life cycle assessment (LCA), although its application to rehabilitation and retrofitting is complex due to existing contributions, material removal, waste management, and the use of emission-intensive new materials such as cement-based composites. This study applies LCA to environmentally friendly UHPC mixtures incorporating industrial by-products to assess their performance at the laboratory level, noting the limitation that service life impacts are not evaluated due to data constraints. The results show that UHPC can be designed with consideration for both material properties and environmental aspects. The main contributing factor is the replacement of a portion of Portland cement with a combination of metakaolin and limestone filler, achieving the required mechanical properties while substantially reducing the overall carbon footprint. Additionally, the use of recycled and waste fibres supports the circular economy with further improvement in environmental impact.

ABSTRACT. Over the past two decades, extensive research has been devoted to investigate the structural performance of concrete columns internally reinforced with fiber-reinforced polymer (FRP) bars. These studies have primarily aimed to develop predictive models for estimating the axial load-bearing capacity (ALBC) of such columns subjected to compression. Despite notable progress, many of the existing ALBC prediction models are derived from limited experimental datasets and are predominantly based on conventional regression approaches. As a result, their prediction accuracy is limited. Recent advances in artificial intelligence (AI) and machine learning techniques offer a powerful alternative for modeling complex structural behavior by capturing nonlinear interactions among multiple influencing variables. In this study, a novel AI-based predictive model is proposed to estimate the ALBC of FRP-reinforced concrete columns with improved accuracy and robustness. The proposed model was developed using a machine learning framework and trained on an extensive experimental database comprising 308 FRP-reinforced concrete column specimens collected from previously published studies. To evaluate the effectiveness of the proposed model, a comprehensive comparative analysis was conducted against fifteen well-established ALBC models available in the literature. The comparison was performed using three widely accepted statistical performance indicators, namely the coefficient of determination, root mean square error, and mean absolute error. The results demonstrate that the proposed AI-based model significantly outperforms all already known existing models.

ABSTRACT. This paper investigates the sorption and desorption behaviour of expanded polystyrene (EPS) containing a certain proportion of mechanically recycled EPS material. Experimental water vapor sorption tests were carried out in a climatic chamber, and sorption–desorption isotherms were determined, with particular emphasis on the hysteresis phenomenon. The experimentally obtained results were compared with predictions of selected mathematical models in order to assess their suitability for describing the hygroscopic behaviour of mechanically recycled EPS. The results revealed a pronounced sorption–desorption hysteresis and larger deviations of model predictions in the desorption range. Based on the comparison and residual analysis, the Peleg model showed the best agreement with the experimental data, while the Oswin model proved to be the least suitable. The findings contribute to a better understanding of the sorption behaviour of EPS with recycled content and provide a basis for practical application of heat, air and moisture transport modelling of construction elements.

ABSTRACT. In recent decades, sustainability requirements have driven the need for longer service life and rehabilitation of existing infrastructure. To enhance the durability of reinforced concrete (RC) structures, new protective methods and products are continually being developed, particularly for structures exposed to aggressive environments. A common problem in older RC structures is reinforcement corrosion caused by concrete carbonation and chloride exposure, resulting from increased CO₂ levels and inadequate concrete quality or cover. To ensure safe continued use, such structures require rehabilitation and protection systems that prevent further corrosion. One effective method is the use of migratory corrosion inhibitors in accordance with EN 1504-9, Principle 11. This paper presents a comparative laboratory study of a migratory corrosion inhibitor product, with and without additional concrete protection systems. Accelerated electrochemical corrosion was induced through cyclic exposure to water and chlorides, and reinforcement corrosion was assessed by monitoring changes in electrical resistance and current density.

ABSTRACT. The role of the Engineer has evolved through different versions of FIDIC Red Books, in particular FIDIC 1987, FIDIC 1999 and FIDIC 2017. Initially the Engineer was expressly determined as impartial (FIDIC 1987). However, the impartiality clause is excluded from FIDIC 1999 and FIDIC 2017 editions. Not only that the impartiality clause is excluded, the GCC of FIDIC 1999 and FIDIC 2017 editions state that the Engineer acts on behalf of the Employer. The only case in which the Engineer does not act in accordance with Employer’s interests is when deciding upon claims raised by the Contractor and the Employer. In these situations, the Engineer must make a fair determination (FIDIC 1999) or act neutrally between the contracting parties (FIDIC 2017). The scope of Engineer’s autonomy as determined in the contracts concluded between the Contractor and the Employer, as per Red Books, also may influence the legal nature of the Consultant Services Agreement concluded between the Engineer and the Employer based on FIDIC White Book. Depending on the will of the contracting parties and the amendments made through PCC, the Consultant Services Agreement may include elements of the contract for services and a contract for mandate. The answer to the question on legal nature of the Consultant Services Agreement hinges on the scope of the Engineer’s autonomy in performing services and project management, which is specified in both the contract concluded between the Contractor and the Employer and the Consultant Services Agreement itself. If the Engineer’s role is determined as impartial, the Consultant Services Agreement prevails with the legal characteristics of the contract for services. Otherwise, if the Engineer is subject to receiving instructions from the Employer and acting on their behalf, the Consultant Services Agreement prevails with the legal characteristics of the contract for mandate.

ABSTRACT. Building structures are exposed to risks of structural failure due to the effects of earthquakes, fires, floods, etc. Furthermore, there is a need for building maintenance management data. In urban areas, building structures have different characteristics (age, applied materials, applied design and construction methods). In order to perform a global assessment of individual damage risks, as well as to prepare the basic foundations for organizing the facility maintenance process, a range of facility data is required. Analyzing the availability of facilities data in urban areas, it was concluded that there are no adequate databases on built facilities that would provide appropriate bases for assessing vulnerability and organizing the facility maintenance. The paper presents the required data on building structures for the purpose of assessing vulnerability, the basis for managing the facility maintenance, as well as other relevant analyses. Urban areas comprise a vast number of buildings requiring rapid and systematic data collection. Systematized data on facilities of the built environment was the basis for creating a software application (a type of expert system) that enables uniform data collection on-site, using a tablet or smartphone. All collected data are stored on the server in the form of application collection, as well as in the form of a database within Excel, which enables further analysis and connection with other software applications. The paper describes the organization of data collection and the BuildCollector software application created for that purpose.

ABSTRACT. Construction and demolition (C&D) waste management is a key lever for circular economy implementation in the built environment, particularly in dense urban projects where logistics and environmental constraints limit available options. This paper presents a data-driven C&D waste management approach for a phased reconstruction of an emergency medical facility in Belgrade (Serbia), where continuous operation requires strict phasing and limited on-site space. The methodology integrates: (i) waste stream mapping and quantity estimates from the project waste management plan; (ii) laboratory classification of the mixed mineral fraction (EWC 17 01 07) using leaching tests and calorific value assessment; (iii) interpretation of on-site environmental monitoring results (noise and particulate matter) relevant to on-site processing; and (iv) a simplified Building Resource Passport concept to structure material data for traceability and future urban mining. The plan shows that preparatory and demolition works dominate mass flows, including ~450 t of concrete (EWC 17 01 01), ~350 t of iron and steel (EWC 17 04 05), ~248 t of bituminous mixtures (EWC 17 03 02) and ~2,500 m³ of excavated soil/stones (EWC 17 05 04), alongside ceramics, cables, gypsum-based materials and packaging, while construction adds further streams (e.g., ~50 t of concrete and ~50 t of iron/steel). Laboratory results confirm the tested mixed inert fraction as non-hazardous, with low leaching and a low lower heating value (<1 MJ/kg), supporting material recovery. Air monitoring indicates compliance of PM10 (31.4 µg/m³) and PM2.5 (19.7 µg/m³) with daily limits, whereas noise monitoring records exceedances, highlighting the need for mitigation if on-site crushing is applied. A circularity-enhanced pathway is proposed, prioritizing selective demolition, on-site crushing and reuse of mineral aggregates, reuse of clean excavated soil, recycling of metals and bituminous mixtures, and separate collection of gypsum- and insulation-based materials. The approach is operationalized through circularity indicators.

ABSTRACT. The paper analyzes the impact of construction activity and public investment on Serbia's economy. Construction is an important economic activity that can have a multiplicative effect on the country's gross domestic product (GDP) in the short term, which is why it is considered an important activity for overcoming economic recession and stimulating economic growth. In the long term, investments in transport infrastructure are an important basis for increasing the production base of a country, since they stimulate the inflow of foreign investment in production capacities, as well as domestic investment, facilitate the transport of goods and people, and thus facilitate the connection and inclusion in international production, supply, and logistics chains. In Serbia, the chosen model of economic growth is based on encouraging foreign direct investment (FDI), but over the past five years, extremely high state investment in construction has been evident. They include investments in road and railway infrastructure, as well as in other public facilities that lack direct production potential (national stadium, EXPO project), which is why they are subject to criticism for their questionable economic effects, especially given the costs they entail. The paper shows that construction activity in Serbia is influenced by various economic, legal, and social factors, especially when these factors increase uncertainty and risk. In this context, the decline in construction activity in Serbia during 2025 contributed to the slowdown in economic growth.

ABSTRACT. For nearly three decades, the Silesian University of Technology (SUT) has progressively advanced its approach to civil engineering education, evolving from an Integrated Project and supervised industrial placements to an institution‑wide Project‑/Problem‑Based Learning (PBL) framework. Drawing on British and Danish pedagogical models, the Faculty of Civil Engineering pioneered the Integrated Project in the late 1990s, leading to the establishment in 2000 of Poland’s first English‑taught, two‑cycle civil engineering programme with a double degree delivered jointly with a Danish institution. Since 2018, the expansion of PBL through the POWER 3.5 programme and the Excellence Initiative – Research University (IDUB) has enabled more than two hundred projects and involved over one thousand students. In civil engineering, this strategy has modernised the curriculum around authentic design–make–test cycles, digital tools, sustainability and safety, and structured reflection, while strengthening student leadership and employability through IPS pathways and dual‑study formats. The article summarises methods and outcomes, evidences the educational impact, and highlights how EURECA‑PRO and the EAGER IMPRESS‑U project support the development of resilient civil engineering education in the context of contemporary crises.

ABSTRACT. Civil engineering education is increasingly challenged to respond to environmental pressures, sustainable construction demands, and the growing complexity of contemporary built environments. Traditional classroom- and laboratory-based teaching models often fail to reflect the interdisciplinary and practice-oriented nature of real engineering processes. This paper explores the application of the living laboratory concept in civil engineering education, using green roofs as full-scale, operational systems that integrate structural, technological, and environmental aspects of building design and execution. The study is based on experiences from the Green Roofs Technician Training Program, an Erasmus+-funded international initiative coordinated by the Silesian University of Technology, which introduced internship-based learning centered on green roof projects. The paper analyzes the educational outcomes of this approach, focusing on competence development in technical analysis, constructability-oriented thinking, and system-level understanding of building performance. Results indicate that embedding students in real construction processes enhances the integration of theoretical knowledge with practical decision-making and fosters adaptive engineering thinking in an international and multidisciplinary context. Furthermore, the paper discusses the transferability of the green roof-based living laboratory model to existing civil engineering curricula, demonstrating its potential as a scalable and modular educational framework. The findings suggest that green roofs can function not only as sustainable building solutions but also as effective educational infrastructure supporting the modernization of civil engineering training.

ABSTRACT. Engineering Mechanics is a foundational course in civil engineering programmes, yet it is frequently associated with high cognitive load, student passivity, and limited engagement. Traditional board-based instruction reinforces a teacher-centred model that restricts student responsibility and discourages active problem solving. This paper presents a case study of a pedagogical redesign aimed at strengthening student agency through structured Team-Based Learning (TBL). The study was conducted in the second semester of a Bachelor’s programme and draws on two years of implementation. Instructor-led demonstrations were replaced by scaffolded team-based problem solving with rotating roles, peer verification, and preserved individual summative assessment. The instructor’s role shifted from solution presenter to facilitator of analytical reasoning. The redesign remained aligned with existing learning outcomes and programme-level requirements. Qualitative evidence from teaching observations, institutional surveys, and student interviews indicates increased responsibility, peer interaction, and willingness to engage with complex problems, alongside reduced anxiety related to public error-making. Peer explanation and structured verification emerged as central mechanisms supporting deeper processing of canonical calculation tasks. Longitudinal grade distribution and success-rate data suggest that strengthened agency did not compromise procedural rigor or formal academic standards. The study demonstrates that student agency can be deliberately supported in calculation-intensive courses through process-level redesign that redistributes epistemic responsibility while maintaining analytical structure and individual accountability. These findings contribute to ongoing discussions on how foundational engineering subjects can simultaneously sustain disciplinary coherence and foster the development of self-regulated and professionally relevant learning practices.

ABSTRACT. The challenge of climate change, with its’ disastrous consequences for society, needs to be overcome, which is highly dependent on achieving the Millennium Goals, as well as the goals of Green and Digital transition. The use of digital technologies is crucial for achievement of the European Green Deal objectives and for reaching climate neutrality by 2050. In today’s rapidly evolving academic landscape, the conversation surrounding digital transformation and the green transition has expanded far beyond technological innovation or environmental stewardship. Instead, it has become a defining imperative for the future of education, work, and society. Within this shifting paradigm, universities play a pivotal role as drivers of progress and stewards of knowledge. As hubs of learning, research, and innovation, they exert substantial influence in shaping the digital competencies, ecological awareness, and responsible behaviors of future generations. The SKILL2SUSTAIN – Boosting Digital and Green Skills for a Resilient and Sustainable Western Balkan Society project is a regional initiative funded by the European Union, aimed at supporting Higher Education Institutions and key societal stakeholders across the Western Balkans in developing the competencies required for the digital and green transition, contributing to a more resilient and sustainable society. The result of stakeholders’ needs investigation in Montenegro is presented in this paper.

ABSTRACT. This paper presents a comparative numerical analysis of seismic slope stability using the Limit Equilibrium Method (LEM) and the Finite Element Method (FEM). Both methods were applied to identical geometric and material models and subjected to the same pseudo-static seismic loading in order to ensure methodological consistency. The influence of slope inclination and horizontal seismic coefficient on the factor of safety and deformation behaviour was investigated. LEM analysis indicates a systematic decrease in the factor of safety with increasing slope inclination and seismic loading, confirming its effectiveness for rapid global stability assessment. FEM analysis, performed using the strength reduction method, yields comparable factors of safety while additionally enabling the evaluation of displacement fields and plastic zone development. A mesh sensitivity study demonstrates that FEM mesh optimisation plays a crucial role in the reliability of numerical results. The adoption of a graded mesh with six-noded elements ensures stable convergence, clearer identification of deformation patterns, and good agreement with LEM results at acceptable computational cost. The study confirms that while LEM is suitable for ordinaty analyses, FEM is essential for detailed seismic performance evaluation of slopes. The results show that similar factors of safety may correspond to significantly different displacement levels, particularly under higher seismic demand, highlighting the limitations of stability assessment based solely on the factor of safety. FEM results further indicate that seismic slope failure develops progressively, with deformation concentrating near the slope crest.

ABSTRACT. In seismically active regions, adding new storeys to older reinforced concrete (RC) buildings designed with outdated codes may significantly alter dynamic characteristics. That’s why in the laboratory at IZIIS, comparative assessment of the seismic performance of RC frame structures with added floors from different lightweight extension typologies: steel frame (STL), light timber frame (LTF), cross-laminated timber panels (XLAM), and timber frames with glass panels (GLS) was done. The goal of these tests was to examine the impact of vertical extension on the structural behavior under seismic loads. To validate the experimental findings, numerical analyses using OpenSees software were conducted. Initially, modal (eigen) analyses were performed to determine the natural frequencies and vibration mode shapes of the structure. Dynamic analyses under seismic ground motion were performed to further assess the behavior of the structure with diferent types of extension. Additionally, incremental dynamic analyses (IDA) were used to develop fragility curves and assess the collapse vulnerability of each system under increasing seismic intensity. The results demonstrate that the structural typology and material characteristics of the added stories significantly influence both the seismic capacity and ductility demand of the base structure. Steel and XLAM extensions exhibited higher stiffness, while LTF and GLS systems showed moderate values consistent with their lightweight and flexible behaviour.

ABSTRACT. This paper focuses on the numerical evaluation of the seismic behavior of a reinforced concrete frame structure without diagonal steel reinforcement elements and five strengthened variants using different steel profiles. Variants include steel diagonal elements with different profiles (CHS 114.3×5, HEA 100, IPE 120, RHS 120×80×5 and UNP 120, all steel grade S235). Comparison is made according to numerical calculation results of structure loaded with seismic action. Paper focuses on comparing lateral displacements and material efficiency of different steel diagonal variants. Structural models are made in the SCIA Engineer 2026 software. Structure is loaded with seismic load from two orthogonal horizontal directions according to Eurocode 8 with return period of 95 years (serviceability limit state). Reinforced concrete frame structure without diagonal steel reinforcement elements demonstrated significant lateral displacements. By implementing steel diagonal reinforcement elements, a notable reduction in structural lateral displacements was achieved, reaching up to approximately 90%. The comparative analysis of different diagonal steel reinforcement elements demonstrated that all strengthening variants significantly improved the global stiffness and seismic resistance of the structure, with the HEA 100 profile providing the most effective performance while consuming highest steel quantity. Numerical results of all analyzed variants confirm that diagonal steel reinforcement elements represent an efficient and practical strengthening solution for existing reinforced concrete frame structures in seismic regions.

ABSTRACT. This study presents a nonlinear time-history analysis of a multi-family reinforced concrete (RC) building located in Herceg Novi, designed with a G+M+5F configuration. The structural system consists of monolithic RC columns, walls, beams, and inter-floor slabs. Vertical and horizontal elements were modeled using linear and surface finite elements, with slabs simulated as rigid diaphragms. Seismic analyses were performed using SAP2000 v21, considering material and geometric nonlinearities, P–Δ effects, and hysteretic behavior of concrete (Takeda model) and steel. Plastic hinges were defined at the ends of beams, columns and walls to capture deformations under earthquake action. A representative set of seven accelerograms from the Montenegro (1979) and Campano–Lucano (1980) earthquakes was applied in the longitudinal direction. The analysis tracked roof displacements, inter-story drifts, base shear, and the moment–plastic rotation relationship. Results indicate that the structure exhibits a stable and ductile response, with plastic rotations developing at the designed locations, effective energy dissipation, and no approach to limited-functionality or ultimate rotation limits. The findings confirm that the building meets all relevant design criteria for load-bearing capacity, stability, and serviceability, ensuring high reliability, long service life, and safety under seismic excitations.

ABSTRACT. The differences between the new generation and old Euro norms represent a crucial area of research in earthquake engineering, as these differences significantly impact the performance of existing buildings. In this context, understanding both the similarities and the critical modifications is essential for ensuring structural safety and resilience. This study investigates the behavior of reinforced concrete buildings that were designed according to older Euro norms when subjected to seismic loads defined by the newer standards. The methodology employed for this research involves pushover analysis that provides in-depth insights into inter-story drifts while remaining relatively straightforward to execute. The case study focuses on a reinforced concrete (RC) frame building subjected to experimental testing in laboratory conditions. A calibrated numerical model is used to perform the pushover analysis, allowing for the precise evaluation of inter-story drifts at various loading stages. These inter-story drifts are calculated for multiple performance levels and are compared against thresholds established by both the old and new Euro norms, as well as different peak ground acceleration levels. This comparison is particularly pertinent as it highlights the varying responses of buildings under contemporary assessment criteria. The results of the analysis reveal differences in inter-story drift values when contrasting the new-generation seismic design code with the earlier version of Eurocode 8. Specifically, the study emphasizes that most scenarios yield larger target displacements under the current code, with notable exceptions for certain soil types at high acceleration levels. This information is crucial for engineers as it elucidates how the updated determination of seismic loads influences the structural performance of reinforced concrete frame buildings. Ultimately, this research contributes to the ongoing dialogue regarding the importance of aligning structural design practices with the latest seismic standards to enhance the overall resilience, profitability and, most importantly, safety of existing and new buildings.

ABSTRACT. In the city of Zagreb, and in other cities across ex Yugoslavia, ex USSR and United states, there is a significant building stock of large panel buildings (LPBs) built before adequate seismic codes were introduced. Large panel buildings are made using large precast reinforced concrete panels, which are connected in situ. LPBs, especially the older ones, usually have poor connections with inadequate detailing between their precast elements, resulting in premature fracture, usually with lower than adequate ductility. Due to a lack of consideration for all failure mechanisms in the original design, it is often very difficult to model behavior of these buildings correctly. This paper focuses on model validation and methodology, and one potential retrofit strategy, through one case study. The building selected for the case study is names JU-61Z, a variant of buildings made using JU-61 system produced by Yugomont. The selected building was made in 16 mostly identical instances in Zagreb, housing about 10 000 residents. Firstly, the structures characteristics and the process of modelling are briefly described. 5 seismic records are selected to represent 475-year return period ground motions. These ground motions are applied on a full scale structural model of the building. Story drifts, base shear and internal forces are observed, with particular attention on the internal forces experienced by individual wall panel element. A small scale sensitivity analysis is conducted with regard to the properties of the wall panel elements and their effect on building story drifts, base shear and internal forces are discussed.