Abstract: This research proposes a robust multi-objective NSGA-II heuristic optimization framework for CFRP (Carbon Fiber Reinforced Polymer) wrapping to promote seismic-resilient and low-carbon high-rise infrastructure. The method integrates nonlinear time-history analysis with a multi-objective genetic algorithm to determine optimal CFRP application conditions, including whether floors require CFRP wrapping, mortar jacketing, steel jacketing, or combinations thereof. It further optimizes CFRP thickness, orientation, design pattern (unilinear, bidirectional, hybrid), coverage, and anchorage details. Optimization simultaneously minimizes overall cost, torsional irregularity index, Park–Ang damage index, and seismic sensitivity while maintaining structural reliability under seismic loading. Simulation results indicate that proposed CFRP framework reduces torsional impacts by approximately 35%, enhancing seismic resilience. Hybrid CFRP configurations combined with 20–40 MPa mortar and optional 10–40 mm steel jacketing showed improved structural performance. Anchorage of 0–2 per end per face reduced torsional drift to ≤0.5–1.0%. For a 10-storey building, lower floors benefit from CFRP with mortar/steel jacketing up to ±45°, mid-level floors from hybrid (0/±45°) configurations, and upper floors from predominantly ±45° CFRP with occasional 90° bands. CFRP thickness of 0–3 mm (0–6 plies) achieved improved seismic resilience, cost efficiency, and structural reliability, supporting its potential for seismic-resilient infrastructure policy and design.

Abstract: The article presents a case study of an event that occurred in Gdańsk, Poland, in 1994. During a rock concert at the old Gdańsk Shipyard Arena, a fire started. The audience was evacuated in a state of emotional agitation. This event resulted in the death of seven people and left many people injured, some of which had permanent injuries. This article presents the technical characteristics of the building where the event occurred and the event course. Based on the analysis of many source materials, the fire course as well as rescue and firefighting operations are described. The fire course was accurately recreated using computer simulations. Analyses conducted immediately after the event 30 years ago primarily concluded that all emergency exits being open would have been sufficient for the evacuation of the crowd in the building. A total of nine evacuation scenarios were simulated, the first of which was the recreation of the real event. In the other scenarios, the conditions were modified to investigate the impacts of the number of people and availability of emergency exits on the outcomes. As a result of the conducted research, the hypothesis regarding the recognition of blocked emergency doors as the main cause of death and injuries of the participants of the analysed event was questioned. The second issue that should be considered innovative was the description of the blocking pile phenomenon. An attempt was made to identify similar situations reported in the literature and elucidate this phenomenon.

Abstract: Soil suction is a crucial factor affecting the hydraulic and mechanical property of unsaturated soils, playing an important role in geotechnical, geoenvironmental, and hydrological engineering applications such as slope stability, foundation design and irrigation planning. Conventionally, measuring and modeling soil suction and its associated curves like Soil Water Characteristic Curve (SWCC) and Soil Water Retention Curve (SWRC) require extensive, time-consuming tests in the laboratory. Recent progress in Machine Learning (ML) offers powerful as well as data-driven and reliable alternatives ways that can enhance the efficiency and accuracy of suction-related predictions across a wide range of soil conditions. This study aims to cover the current state of the art research on the integration of ML techniques into the prediction and analysis of soil suction behavior. Studies utilized various algorithms including Random Forest (RF), Extreme Gradient Boosting (XGBoost), Artificial Neural Networks (ANNs), Support Vector Machine (SVM), Multi-Expression Programming (MEP), K-Nearest Neighbors (KNN), and AdaBoost (AB) to predict soil suction. These models demonstrated high predictive performance (R² > 0.90 in majority cases) based on soil parameters which can be easily evaluated like soil texture, bulk density, climate parameters, and remotely sensed data. Overall, this study covers the understanding of the current research gap related to SWCC and SWRC using different data driven and ML techniques.

Abstract: Three-dimensional printing (3DP) has attracted growing attention in the construction industry due to labor shortages and the need for greater efficiency. However, there have been only a few previous studies focused on mixture design strategies that address the thixotropy of fiber-reinforced mortars for 3DP. In addition, the relationships among thixotropy, printability, and interlayer stability have not been sufficiently verified. This study aims to establish a quantitative method for evaluating the thixotropic properties of mortars used in construction 3DP, specifically on their practical applicability at construction sites. Vane shear and 15-stroke flow tests are conducted on mortars incorporating polyvinyl alcohol (PVA) fibers to assess their thixotropic behavior under static and dynamic conditions. Fiber-reinforced mortar mixtures are prepared, and their compressive and flexural strength developments over time are examined. The results indicate that the vane shear test is a sensitive and effective method for detecting changes in mortar rheology, particularly in response to variations in fiber content and admixture dosage. The inclusion of PVA fibers increased the maximum shear stress owing to fiber aggregation, resulting in atypical thixotropic behavior compared to that of fiber-free mortars. While the 15-stroke flow test provided supplementary information on flowability, the vane shear test exhibited a stronger correlation with mechanical properties and printed build quality. These findings suggest that vane shear testing offers a practical and reliable means of evaluating and managing the thixotropic properties of mortars for 3DP, thereby enhancing quality control in additive construction.

Abstract: This study analyzes the spatiotemporal variability of carbon monoxide (CO) column density along the Lima–Huancayo section of the Central Highway in Peru during the 2019–2024 period, using data from the TROPOMI instrument onboard the Sentinel-5P satellite and official records of vehicular traffic flow. An approach based on remote sensing and exploratory statistical analysis is employed to examine the spatial and temporal patterns of atmospheric CO and its co-variability with vehicular activity at representative control points along the highway corridor. The results show heterogeneous spatial patterns and differentiated temporal behaviors, as well as statistical associations between traffic variability and CO column density at a regional and long-term scale. Given that satellite observations represent vertically integrated atmospheric content and that explicit meteorological variables are not incorporated, the findings should be interpreted as exploratory, non-causal relationships that contribute to understanding the regional dynamics of CO in transportation corridors located in complex Andean environments.

Abstract: The most common defect in reinforced concrete structures is corrosion damage to the working reinforcement within the concrete. The primary risks associated with corrosion damage include: the volumetric expansion of corrosion products, which induces additional tensile stresses in the concrete along the bar length leading to spalling of the protective layer; reduction of the working reinforcement diameter; and localized exposure of reinforcement due to the destruction of the protective layer. Numerous methods exist for assessing the stress-strain state of damaged structures, but specific refinements to calculation methods are required for each damage type. This paper presents an analysis of domestic and international literature on the assessment of reinforcement bonding with concrete, along with the authors' experimental test results evaluating bond loss in corrosion-damaged reinforcing bars embedded in concrete.

Abstract: Accurate prediction of transverse shear deformation is essential for the serviceability assessment, durability-oriented design, and structural health monitoring of hybrid and heterogeneous beam members. This is particularly relevant for lightweight composite components in which a porous cementitious matrix (e.g., perlite-based material) is combined with an embedded steel I-section, yielding strong stiffness contrasts and spatially nonuniform shear transfer. In this study, an energy-consistent analytical–numerical framework is proposed to determine the effective shear correction factor k_s for such non-homogeneous cross-sections within the Timoshenko beam theory. The formulation enforces equivalence between the real heterogeneous shear strain energy, governed by a spatial shear modulus field G(y,z), and its beam-theory representation based on k_s(G_ref A). A pixel/voxel discretization is introduced to evaluate the generalized shear-energy integral and to quantify the deviation of k_s from classical homogeneous benchmarks. The results demonstrate that shear stiffness may be controlled by localized energy concentrations near weak matrix regions and phase interfaces, which can lead to non-negligible errors in deflection predictions when standard shear correction factors are adopted. The proposed framework provides a transparent and computationally efficient tool to support reliability-driven stiffness identification, model updating, and health monitoring strategies for heterogeneous and hybrid beam components.

Abstract: Coal gangue (CG) is one of ranks among China's most significant industrial by-products. In response to China's carbon neutrality commitments and the growing emphasis on resource recycling, finding effective ways to valorize CG has emerged as a pressing concern. Based on the mineral composition and chemical composition characteristics of CG, this study systematically investigated the enhancement effects of three alkali activators (sodium silicate, NaOH, and Ca(OH)₂) on the cementitious properties of CG. Through different dosage and compressive strength tests, the efficiency ranking of the three activators was determined as: sodium silicate > Ca(OH)₂ > NaOH. A 10% sodium silicate dosage combined with 28-day curing was identified as the optimal condition for achieving sufficient reaction and structural densification. Under these conditions, the compressive strength of CG cementitious material reached 6.4 MPa, representing an increase of 190.9% compared to the blank group (2.2 MPa), significantly superior to Ca(OH)₂ (69.55%) and NaOH (62.27%). X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analyses revealed thatalkali activators function primarily by disrupting the crystalline framework of CG, promote the cross-linking polymerization of silicon-aluminum monomers to generate dense cementitious products, thereby improving material performance. The sodium silicate is attributed to its “dual activation effect”, providing OH⁻ to create an alkaline environment while supplying reactive silicate ions (SiO₃²⁻) to accelerate N-A-S-H gel and C-A-S-H gel formation. These findings offer guidance for optimizing CG-based cementitious formulations for the formula optimization and large-scale utilization of CG cementitious materials.

Abstract: Rising damp is one of the most common problems affecting older buildings. This phenomenon also leads to material degradation, reduced indoor air quality, increased energy consumption, and possible respiratory diseases in people who are exposed to such an environment for long periods of time. This article presents the results of long-term research focused on assessing the effectiveness of undercutting masonry as a remediation measure against rising damp. The moisture condition of the structure was monitored for several years at several designated locations, both before and after remediation. The results obtained show a gradual but permanent reduction in moisture. This fact confirms the high effectiveness of the proposed remediation technology. The study further discusses the consequences of possible residual moisture for the possibility of subsequent application of thermal insulation. It pays particular attention to the limitations of some contact insulation systems and the potential of active thermal protection as a possible alternative approach. This proposal is identified as a promising strategy for improving the thermal and moisture properties of the structure.

Abstract: In geotechnical engineering, operations such as foundation pit excavation, slope cutting, and tunnel boring often involve lateral unloading under plane strain conditions. This unloading pattern exhibits significant differences from the traditional axisymmetric triaxial loading path. To investigate the mechanical behavior of silt under such conditions, a series of plane strain tests were conducted using a self-designed plane strain apparatus, focusing on both vertical loading (constant lateral stress) and lateral unloading (constant vertical stress) paths. The results indicate that the failure of soil during unloading can be identified as the stage where the vertical deformation rate first increases and then decreases, corresponding to a distinct inflection in the stress-strain curve. The internal friction angle remained essentially constant regardless of the stress path, dry density, or consolidation stress ratio, while cohesion was higher under loading than under unloading. Failure deviatoric stress increased linearly with vertical consolidation stress and was unaffected by the consolidation stress ratio. The classical limit equilibrium condition remains valid for unloading under both isotropic and anisotropic consolidation. These findings provide a practical criterion for failure detection and highlight the necessity of adopting plane strain parameters in the design of lateral unloading engineering works.

Abstract: Carbonation degrades reinforced concrete structures and reduces their service life, and it raises environmental concerns. Moreover, the cement industry faces increasing pressure to mitigate CO2 emissions. Therefore, this study developed a functional mortar incorporating microcapsule (MC) technology to suppress carbonation and enhance CO2 absorption. Two types of MCs were prepared: alkali-supplying MCs for carbonation resistance and CO2-absorbing MCs for carbon fixation. Mortars incorporating these MCs were evaluated using compressive strength tests, accelerated carbonation tests, and CO2 absorption measurements. The alkali-supplying MCs effectively suppressed carbonation, particularly at a dosage of 10%. However, the compressive strength decreased owing to the low strength and density of the MCs. The CO2-absorbing MCs significantly increased the CO2 uptake, particularly when impregnated with amines such as trioctylamine. However, they did not suppress carbonation, and their absorption capacities decreased over time. MCs without amine impregnation absorbed CO2, although they did not affect the carbonation depth owing to the absence of reactive components. These findings demonstrate the potential of MC-based mortars to improve the durability of concrete and promote carbon management. The use of cementitious materials with CO2-absorbing and protective functions is a promising approach for sustainable construction and long-term infrastructure resilience.

Abstract: This research investigates the validation of hermeticity in 3D-printed vacuum enclosures for smart façade systems, highlighting the critical need for airtightness in architectural applications. Using a pressure decay leak testing method under vacuum, guided by BS EN 1779:1999 criteria for method selection and based on ASTM F2095 − 07 (Reapproved 2021) standards, we created a controlled depressurization of the enclosure up to 1 bar with a manual vacuum pump. Different depression values were read at intervals of 20, 40 and every 60 minutes to detect any drops indicative of leakage. The results demonstrated that our method reliably identified even minor leaks, with constant pressure stability confirming the hermetic integrity of the housing. These findings suggest that our approach provides a practical, low-cost, and non-destructive measure for complex 3D printed components in advanced façade systems. Moreover, the methodology is adaptable to various geometries and materials, providing manufacturers with an effective tool to ensure the reliability and performance of integrated facades of smart buildings.

Abstract: Topological optimization has established as an efficient tool for the design of structures with high complexity and rational use of material, especially in problems involving multiple constraints and conflicting objectives. This work presents a new multi-material topology optimization approach based on the ESO smoothing method (SESO), formulated as a multi-objective optimization problem in a MATLAB environment. The multi-objective formulation simultaneously considers the minimization of the maximum von Mises equivalent stress and the maximum displacement, fundamental criteria for structural engineering design. The proposed methodology also incorporates a reliability analysis using the First-Order Reliability Method (FORM). The uncertainties associated with the applied force, volume fraction, and elastic modulus are modelled using normal and lognormal probability distributions, with a target reliability index of β_target=3.0. The consistency of the reliability analysis was evaluated through Monte Carlo simulations, used to validate the reliability indices obtained by the FORM method. The approach was applied to two classic three-dimensional numerical examples, a bottom-loaded cantilever beam and center-loaded cantilever beam, considering two widely used commercial materials, steel and concrete. The results indicated better multi-material distribution in the design domain and increased structural robustness against unfavorable loading planes, elastic modulus, and volume constraints imposed by the FORM formulation. Furthermore, the minimum yield stress is calibrated to incorporate the uncertainties inherent in the design process, establishing the minimum value required to achieve the target reliability index β. Thus, this method highlights the integration of the SESO method with multi-material, multi-objective, and reliability-based optimization as a consistent and robust strategy with potential for future applications in structural engineering design.

Abstract: Performance‑based evaluation of reinforced soil retaining structures often relies on numerical analyses that require substantial time and expert judgment due to the complex interactions among soils, reinforcements, facings, and seismic loading. This study presents an efficient approach for developing seismic resisting capacity curves for reinforced slopes using a computer program based on the Force Equilibrium Finite Displacement Method (FFDM). The resulting curves resemble the monotonic pushover curves widely used in structural engineering, indicating that the framework is aligned with established performance‑based methodologies. The method is demonstrated by revisiting the Tanada Wall, a geosynthetic reinforced soil retaining wall with a full height rigid facing that experienced strong shaking during the 1995 Hyogoken Nambu earthquake (ML = 7.2). Using parameters available in published databases, the FFDM generates realistic seismic resistance curves and directly computes seismic displacements. Three advantages distinguish the FFDM from LEM based Newmark approaches: explicit incorporation of peak soil strength and post peak degradation along the slip surface; direct use of peak ground acceleration (HPGA/g) as input, avoiding uncertainties in selecting representative seismographs; and capability for back analysis, enabling soil parameters calibrated from small observed displacements to be used for predicting performance under stronger shaking. A conceptual back analysis procedure is introduced to illustrate this potential.

Abstract: Counter and concurrent flow in channels separated by membrane were studied to simulate the mass transfer through the membranes in many experimental and theoretical published research, where limited of them use the computational fluid dynamics (CFD). The current study aims to numerically simulate and physically describe the mass transfer in the counter current flow by solving Navier–Stokes (N-S) equations in the channel and membrane holes (vertical channels), while most of the previous studies, the channel flow is simulated by using N-S equations and ultra-filtration flow (membrane holes-vertical channel) is simulated by using Darcy’s Law. Consequently, the current study was implemented by using CFD to achieve several significances: avoiding the experimental tests execution, reducing the effort of module design for expensive and time-consuming, and easy observing of the variations in pressure, horizontal and vertical velocity for the model. Two-dimensional CFD Methods directly simulated the flow in channels and membrane holes to solve the Navier-Stokes (N-S) equations in each point in the whole domain where the velocity (horizontal and vertical) and pressure are calculated. In the current study it was found that the pressure decreases from inlet to the outlet of the upper and lower channel, the horizontal velocity decreases from the inlet to middle of the upper and lower channel length and increases to the outlet of the upper and lower channel, and the vertical velocity decreases from the inlet to the middle of the upper and lower channel length and increases to the outlet of the upper and lower channel. The results perfectly explored and displayed the flow distribution patterns inside channels and described the ultra-filtration profiles along the surface and in the holes of the porous membrane which is like the hemodialysis process.

Abstract: Based on the scientific and technological revolutions that have characterized Structural Engineering during the last two centuries, we can acknowledge how the historical scale doubling of suspension bridges has occurred for at least four times, from the beginning of the XIX to the end of the XX Century. These four revolutions represent the tangible mankind’s challenge against natural forces: gravity, wind, earthquake. In this context, the prospective scale doubling requested by next-generation bridges (e.g., the Messina Straits Bridge) could take place only if significant scientific and/or technological innovations occur. This opportunity is presently offered by Fracture Mechanics, since any appropriate advanced design approach should take into account also brittleness size-scale effects, in addition to loading-capacity size-scale effects, which are well-known since Galileo’s studies. From the technological point of view, the open problem of physical similitude could be effectively solved by using fibre-reinforcement.

Abstract:

This study investigates the critical interplay between cement grade (32.5, 42.5, 52.5) and fiber/cement ratio (1/2 to 1/5) in determining the performance of cement-bonded fiberboards. Experimental results highlighted a fundamental trade-off: while reducing the fiber content significantly enhanced mechanical strength and moisture resistance, it naturally diminished thermal insulation capabilities. The analysis identified the 42.5 cement at a 1/4 ratio as the optimal formulation, offering the most effective balance between structural integrity and physical stability. To understand the mechanism behind this performance, the study employed multi-scale characterization using FTIR, XRD, and SEM. These analyses revealed that the superior properties of the optimal formulation stem from a denser hydration product network and improved fiber encapsulation. Specifically, the 42.5 cement facilitated a more robust Calcium-Silicate-Hydrate (C-S-H) gel formation compared to the 32.5 types, creating a stronger fiber-matrix interface. These findings provide a scientific basis for tailoring fiberboard production, demonstrating that material properties can be precisely engineered for either load-bearing or insulating applications.

Abstract: This study presents a multi-index performance method to measure the synergy of nano-silica-enhanced binders in resource efficient alkali-activated composites based on the Strength Activity Index (SAI) as a reference index according to ASTM C618. High-calcium fly ash (HCFA) and low-calcium fly ash (LCFA) were used with fine aggregate replacement level is kept constant at 20% by mass and nano-silica was incorporated at 0, 1, 2, and 3 wt% of the binder to prepare alkali-activated slag fly ash composites. The fresh state performance was assessed using the Initial Flow Index (IFI) and Flow Retention Index (FRI), while the mechanical performance was evaluated using the compressive, tensile, and flexural indices (SAI, TSI, and FSI). These results indicate that with an increase in nano-silica content, flowability and workability retention reduces systematically, with LCFA-based mixtures always exhibiting higher fresh-state retention than HCFA systems. Optimal mechanical performance was achieved with an intermediate nano-silica concentration of about 2 wt%, with consequent maximum SAI performance of about 120% at 28 days with HCFA-based mixtures and 118% at 28 days with LCFA-based mixtures, as well as a uniform improvement in TSI and FSI. Correlation analyses between SAI and tensile and flexural indices revealed clear linearity (R² of about 0.91-0.95) which indicated that compressive strength is not a sufficient measure of total mechanical performance. The mineralogical and microstructural analyses assisted by X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that the performance trends observed depend on the interactions of the calcium supply, amorphous aluminosilicate and the nucleation effects of nano-silica. The proposed solution provides a performance-based approach towards the optimal utilization of nano-silica-modified alkali-activated composites to be used in sustainable infrastructure applications.

Abstract: In caving mining, irregular large top coal blocks formed due to overburden pressure and gravity often obstruct the drawing mouth, reducing efficiency, yet studies on their crush-ing characteristics remain limited. This study aims to investigate how fracture modes and geometry affect the fragmentation behavior of such coal blocks. Uniaxial compression tests were conducted on irregular top coal samples from a Gansu mine, with numerical simulations employed to analyze the influence of microscopic parameters. Results indi-cate that among four fracture modes, multi-peak and flat coal blocks exhibit better frag-mentation but higher crushing strength, while single-peak and blade-shaped blocks break unevenly with lower strength. Numerical simulations reveal that porosity affects both crushing strength and fracture direction concentration; elastic modulus influences break-ing time; bond stress impacts strength and breaking time; and loading rate alters crushing characteristics. The findings provide a basis for optimizing caving parameters and pre-venting blockages, contributing to improved mining efficiency.

Abstract: Engineering education faces growing demands to prepare graduates capable of addressing complex sustainability challenges, public safety concerns, and ethical responsibilities. However, sustainability and ethical education are often delivered as supplementary content, limiting their integration with core engineering instruction. This study examines and evaluates a curriculum reform of a Building Water Supply and Drainage Engineering course that systematically integrates sustainability, ethical responsibility, and human-centered values into technical teaching through a CDIO-oriented approach. A quasi-experimental pre–post design was employed with a full cohort of 100 undergraduate engineering students. Data were collected using a sustainability-oriented questionnaire, project-based assessment rubrics, and student reflection reports. Quantitative data were analyzed using paired-sample t-tests and effect size calculations, while qualitative data were thematically coded to support interpretation of the results. The findings demonstrate statistically significant and practically meaningful improvements in students’ sustainability awareness, ethical responsibility, human-centered design thinking, and systems thinking. Project assessment results further reveal students’ ability to apply sustainability principles and ethical considerations in engineering design tasks. These results provide empirical evidence that value integration within core engineering courses enhances both technical competence and professional responsibility. This study contributes empirical evidence to Education for Sustainable Development in engineering education by demonstrating a transferable pedagogical model that embeds sustainability and ethics into discipline-specific engineering instruction without increasing curricular load.