Search Results (985)

Structural health assessment of historic buildings frequently relies on finite element (FE) model updating, yet high-dimensional parameter identification under sparse, noise-contaminated modal data can reduce robustness and lead to prohibitive computational cost. This paper proposes an application-oriented integrated workflow that improves identification stability while accelerating the updating process. A multi-indicator objective function is formulated by combining residuals of natural frequencies and mode shapes with sensitivity-based consistency relations. The inverse problem is solved using the Mayfly Algorithm (MA), and a deep neural network (DNN) surrogate is introduced to replace repeated FE modal analyses during the optimization, thereby reducing the overall computational burden. The proposed workflow is demonstrated on the Christian Lutheran Church in Wuhan, China, constructed from 1923 to 1924, using operational modal testing data collected at 25 measurement points. A refined FE model is updated by identifying 24 grouped stiffness reduction coefficients that represent columns, beams, walls, and slabs across different floors. The updated model shows substantially improved agreement with the measured first four natural frequencies and corresponding mode shapes, enabling a quantitative diagnosis of stiffness degradation and supporting stiffness-oriented reinforcement planning. A stiffness enhancement target of 20% is adopted to guide intervention measures, and an analytical modal enhancement check is provided to relate the stiffness target to the expected frequency gain. The workflow offers a reproducible route for data-informed decision support in heritage building assessment and rehabilitation, while uncertainty quantification and post-intervention validation are identified as key priorities for future work. Under the available sparse modal information, the inverse problem is underdetermined; therefore, the reported stiffness-reduction coefficients should be interpreted as non-unique grouped solutions affected by modelling and measurement uncertainty, and the reinforcement measures are presented only as planning-level design proposals requiring post-intervention verification. Full article

This paper introduces a comprehensive framework for optimizing daylight performance in architectural drawing rooms located in hot-arid climates through the integration of building performance simulation and political optimizer algorithms. The study investigates the key challenge of balancing daylight availability with visual comfort in educational spaces characterized by high solar radiation intensities. A sophisticated 3D simulation model was created using MATLAB, embedding 15 CIE standard sky types to accurately represent the dynamic luminous environment of hot-dry regions. Empirical validation conducted in Biskra, Algeria, demonstrated high model accuracy with a mean error of 3.5%. The political optimizer algorithm was employed to solve a multi-objective optimization problem addressing three key performance indicators: illuminance uniformity, Useful Daylight Illuminance (UDI 300–3000 lux), and task-specific illumination levels (300–500 lux). Optimization results indicated marked improvements, with UDI occupancy rates increasing from 20.66% to 37.66%, representing an 82% relative enhancement. The optimal configuration identified includes a 30% window-to-wall ratio, 70% glazing transmittance, and strategic surface reflectances (ceiling: 80%, walls: 65%, floor: 35%). This research provides a validated computational framework that allows architects to make evidence-based design decisions for educational spaces in climatically challenging settings, effectively bridging the gap between building performance simulation and practical architectural applications. Full article

Lean Six Sigma (LSS) improvement work increasingly depends on information-intensive activities such as document handling, data interpretation, reporting, and communication, yet current discussions of Artificial Intelligence in LSS remain largely technology-centric. This paper proposes a task-first, process-centric framework to support the governed application of Large Language Model (LLM)-enabled tools in such environments. The study makes three contributions: (i) a set of cross-functional organizational process types relevant to LSS practice, (ii) a functional classification of recurring tasks and LLM-enabled tool categories, and (iii) a dual-encoded task–tool matching matrix that separates alignment strength from interaction mode, distinguishing capability fit from governance logic. The framework is empirically anchored through two real-world industrial applications: customs document processing and shop-floor data digitalization and reporting. The results show that (i) stronger outcomes emerge when LLM-enabled support is matched to bounded, repetitive, and structured work, or when analytical support is built on stable and traceable data layers; (ii) operational value depends not only on technical capability, but on workflow embeddedness, data readiness, and human validation checkpoints. The framework also clarifies where support, augmentation, and partial automation are appropriate for different task classes and under explicit accountability constraints in information-intensive administrative work connected to improvement practice and governance. Full article

To improve construction efficiency for large-section tunnels in sandstone–mudstone strata, this study investigates the applicability of the two-bench method and the three-bench method for grade IV and grade V surrounding rock, respectively. Based on FLAC3D, numerical simulations of excavation and support for the two benching methods were conducted to analyze deformation responses, including ground settlement, crown settlement, haunch convergence, floor uplift, and face extrusion. The simulation results were then compared and validated against field monitoring data to evaluate the applicability and feasibility of the construction methods. The results show that, for grade IV surrounding rock excavated using the two-bench method, crown settlement, floor uplift, and horizontal convergence converge and stabilize on days 17, 15, and 25, with stable values of 14.0 mm, 10.3 mm, and 13.2 mm, respectively. For grade V surrounding rock excavated using the three-bench method, these indices stabilize on days 24, 22, and 32, with stable values of 26.3 mm, 20.3 mm, and 20.8 mm, respectively. The surrounding rock pressures at the crown and spandrel gradually attenuate after excavation and stabilize at 1–4 MPa after approximately 20–26 days, whereas stress release at the haunch lasts longer and the stabilized stress level remains higher. Meanwhile, the anchor bolt axial force at the haunch is significantly greater than that at the spandrel, indicating that the haunch is a critical zone for support load-bearing and deformation control. The benching method can effectively control surrounding rock deformation under grade IV and V surrounding rock conditions in sandstone–mudstone strata; however, in engineering practice, the haunch should be treated as a key monitoring target, and targeted support and reinforcement measures should be implemented. Full article

Background: Mandibular second molars show notable variability in root canal structures and C-shaped morphology, with possible differences among populations. Methods: This retrospective cross-sectional CBCT study included 500 patients attending the Department of Dentistry at IRCCS Ospedale San Raffaele (Milan, Italy) with bilateral mandibular second molars and was reported according to STROBE guidelines. CBCT scans (Hyperion X5; voxel size 0.125 mm) were assessed by two endodontists using standardized criteria. Root-based canal configurations were classified according to Vertucci in cases with complete bilateral coding of homologous mesial and distal roots; C-shaped morphology was classified using Fan’s system and analyzed separately because Vertucci coding is not applicable to C-shaped systems. Categorical variables were analyzed using χ² or Fisher’s exact test, continuous variables with parametric or non-parametric tests, and right–left comparisons with paired-sample tests (p < 0.05). Results: Complete bilateral Vertucci coding was feasible in 494/500 patients (98.8%), yielding 988 mesial and 988 distal roots for analysis. C-shaped canal configuration was detected in 1.2% of patients (6/500; 95% CI 0.44–2.59%); females showed a higher proportion than males (2.0% vs. 0.4%), with no evidence of a sex association (Fisher’s exact test, p = 0.216). Fan subtype annotation was available for 5/6 patients and 7 teeth; C1, C3, and C4 patterns were observed. In the Vertucci dataset, mesial roots most frequently exhibited Types II (52.0%) and IV (26.5%), whereas distal roots were predominantly Type I (62.4%), followed by Type III (29.8%). Contralateral symmetry was observed in 27.3% of mesial roots (135/494; 95% CI 23.4–31.5%) and 59.1% of distal roots (292/494; 95% CI 54.6–63.5%). Mean pulp chamber roof-to-floor distance was 2.623 ± 0.263 mm on the right and 2.567 ± 0.343 mm on the left (paired p < 0.001; mean difference 0.056 mm; 95% CI 0.023–0.089 mm). Conclusions: In this cohort, C-shaped morphology was rare, and no evidence of a sex association was found, although the small number of cases limits statistical power. Mesial roots showed more variability than distal roots, and contralateral symmetry was moderate and greater for distal roots than for mesial roots, supporting contralateral anatomy as a helpful—rather than predictive—clinical reference. Full article

Background/Objectives: A marked anteroposterior gradient of nasal fossa pneumatisation over the posterior maxillary alveolar base has been documented at the second premolar level, yet whether this gradient extends to the second upper molar (M2)—the primary site for posterior implant rehabilitation—remains uncharacterised. We aimed to quantify this gradient by classifying pneumatisation patterns above the maxillary alveolar base at M2 (Type 1: pure antral; Type 2: antral with palatine recess; Type 3: Big Nose pattern with combined antral and nasal involvement), assess bilateral symmetry and sex distribution, and compare findings with published second premolar data. Methods: A retrospective study was conducted on 165 cone-beam computed tomography scans (330 sides) from a Romanian population. Patterns were classified as Type 1 (pure antral), Type 2 (antral with palatine recess), or Type 3 (Big Nose pattern). Bilateral symmetry was assessed using Cohen’s kappa, and sex differences using Fisher’s exact test. Results: Type 1 was observed in 93.3% of sides, Type 2 in 4.2%, and Type 3 in 2.4%. Bilateral symmetry was 98.8% (kappa = 0.904), with all Type 3 cases occurring bilaterally. No significant sex difference was found (p = 0.363), although Type 3 showed a non-significant male predominance (OR = 4.55; p = 0.305). The Big Nose pattern was 6.8-fold less prevalent at M2 than at the second premolar level. Conclusions: A 6.8-fold reduction in Big Nose prevalence from the second premolar (16.2%) to M2 (2.4%) confirms a pronounced anteroposterior gradient in nasal fossa involvement over the posterior maxillary alveolar base—the central finding of this study. At M2, the maxillary sinus dominates exclusively in 97.6% of sides, rendering standard sinus floor elevation highly predictable. The invariable bilaterality of the Big Nose pattern at M2 supports contralaterally symmetrical surgical planning. These findings provide a gradient-based clinical framework: nasal-floor-aware augmentation planning is essential anteriorly (premolar region), whereas standard sinus augmentation protocols are reliably applicable at M2. Full article

Waste tire disposal and high-ground-stress soft rock roadway instability are pressing global challenges. This study develops sustainable rubber granule concrete (RGC) using waste tire rubber as a key component, aiming to realize waste valorization and floor heave control. RGC’s mechanical properties (uniaxial/triaxial compression, compressibility, ductility) were systematically tested, and its pressure relief mechanism was validated via finite element analysis (ABAQUS/FLAC) and 60-day field monitoring. Results show that RGC with optimal parameters (12% rubber content, 3–4 GPa elastic modulus, 250–350 mm thickness) achieves 64% bottom stress reduction and >40% displacement control. The material’s excellent energy absorption and flexibility address the brittleness of conventional concrete, ensuring stable support in high-stress environments. This work provides a sustainable, cost-effective concrete modification strategy, bridging waste recycling and geotechnical engineering, with broad implications for low-intensity, high-toughness material applications. Full article

Background: Artificial intelligence (AI) has shown promise in the interpretation of electrocardiograms (ECGs) using signal-based deep learning models. In parallel, large language models (LLMs) have gained increasing visibility in clinical practice, including exploratory applications in ECG analysis. Whether a general-purpose LLM can meaningfully discriminate cardiovascular disease from athlete ECGs during PPS remains unknown. We aimed to evaluate the diagnostic performance of a general-purpose LLM for this task. Methods: In this multicentre diagnostic accuracy study, we evaluated a commercially available LLM (ChatGPT, version 5) in 2950 competitive athletes undergoing PPS. All athletes underwent resting 12-lead ECG, with second- and third-line investigations performed when clinically indicated. The reference outcome was confirmed cardiovascular disease after full diagnostic work-up (n = 450, 15.3%). For each ECG, the LLM generated a numeric score (0–100) representing the inferred likelihood of underlying disease using a standardized prompt and without task-specific fine-tuning. Discriminative performance was assessed using receiver operating characteristic (ROC) analysis. Misclassification patterns were analysed according to International ECG Criteria. Results: GPT-derived scores demonstrated a marked floor effect, with a median value of 0 (IQR 0–2) in both diseased and non-diseased athletes and substantial overlap between groups. The area under the ROC curve was 0.52 (95% CI 0.49–0.55), indicating performance close to random classification. At the Youden-derived threshold, 79% of athletes with confirmed disease were incorrectly classified as negative. False-negative cases were predominantly characterized by borderline ECG patterns (82%), and a substantial number of red-flag ECG abnormalities were also missed. Conclusions: In this PPS cohort, a general-purpose LLM used in a naïve configuration showed no clinically meaningful ability to discriminate between cardiovascular disease and athlete ECGs. Without task-specific training or domain adaptation, such models should not be used for diagnostic triage in athlete screening. Full article

Damping modeling significantly influences the numerical seismic response of buildings, something that, despite being repeatedly emphasized in earthquake engineering research, is still overlooked even by seismic codes. It is a fact that, for simplification and ease of application, modern seismic design provisions assume damping for buildings entirely composed of a single material, e.g., reinforced concrete or structural steel. The current codes offer no guidance on damping assumptions for so-called mixed buildings comprising a lower part (stories) of reinforced concrete and an upper part (stories) of structural steel. Despite the growing use of mixed reinforced concrete-structural steel buildings, damping modeling of their seismic response remains almost unexplored. This study aims to contribute to this field by investigating the effect of different damping models on the elastic and inelastic seismic response of realistic three-dimensional mixed buildings. Modal response spectrum and time-history analyses served for this purpose. Key seismic response parameters, including interstory drift ratios, floor accelerations, and base shear demands, are extracted and systematically compared for the examined damping models. The results highlight the sensitivity of computed seismic demands to the assumed damping model. Guidance on selecting a damping model for the seismic analysis of mixed reinforced concrete-structural steel buildings is provided. Full article

Accelerated industrial development, mass production, economic viability, and environmental sustainability impose new requirements on contemporary materials, positioning basalt as a promising, cost-effective, and abundant environmentally benign raw material. This study explores the influence of sintering temperature on the physical properties of ceramics obtained from andesite basalt aggregate. Relative density, shrinkage, and color changes were monitored to optimize the sintering temperature for the serial production of high-density ceramics. Varying the sintering temperature by 10 °C within the 1040–1080 °C range, while maintaining a constant sintering time of 60 min, leads to significant changes in relative density, shrinkage, and color. Beyond visual appearance, color changes can be quantified with coordinates in color spaces, usually in the CIELAB color space, standardized by the Commission Internationale de l’Eclairage (CIE). The best physical properties were achieved at a sintering temperature of 1060 °C for 60 min with a relative density of 99.501%, shrinkage of 12.811%, and color coordinates L*(32.03), a*(9.25), and b*(7.58) according to the CIELAB analysis. The favorable physical properties and distinctive reddish-brown color of sintered andesite basalt ceramics make them promising for floor and wall tile applications. Full article

This article analyses the possibility of the application of advanced fasteners in the construction of steel–concrete composite beams. The fasteners were made of corrugated metal sheet with a thickness of 1.00 mm, were in a dovetail shape, and had 2 or 4 shot nails in a single sheet fold. The nails were shot through the sheet into the flange of the steel I section. The 7.5 m-long beam was subjected to an experimental bending test. Based on the test results, the load-bearing capacity and failure mode of the beam were identified, enabling an evaluation of the feasibility of employing beams with innovative connectors in the construction of lightweight ceilings. A numerical model of the beam was constructed in ADINA using findings from experimental studies. A concrete material model, which considers both post-cracking and crushing behaviour and which enabled the identification of critical failure zones, was implemented. The beam connectors demonstrated sufficient load-bearing capacity, whereas the concrete slab was identified as the weakest component within the composite beam assembly. The proposed solution can be suitable for use as a fastener in steel–concrete composite ceiling structures in small utility public buildings. In accordance with Eurocode 4 requirements, the floor beam can carry a load of up to 5.7 kN/m². Full article

Hydraulic fracturing of unconventional reservoirs requires accurate fracture monitoring for treatment optimization. Low-frequency distributed acoustic sensing (LF-DAS) in neighbor wells provides dense strain-rate observations, but gauge-length averaging limits spatial resolution and merges closely spaced fracture features. This study formulates gauge-length averaging as an explicit convolution operator and develops a regularized inversion method combining Tikhonov smoothing, a recursive prior, and L-curve parameter selection, supported by a semi-analytical multi-fracture forward model. On a synthetic benchmark, the method advances the effective resolution from the 10 m gauge-length scale to the 1 m sample-spacing scale, recovering fracture count in all hit-window time slices (versus 32% for raw data), achieving Pearson correlation of 0.80 versus 0.29, with peak-position error reduced by 47%. Noise-sensitivity analysis indicates a practical SNR floor near 20 dB, and Wiener-filter comparison confirms 1.5–2.7× correlation and 1.5–2.3× peak-count advantages across tested noise levels. Field application to HFTS-2 B1H stages 22 and 23 reveals previously hidden tensile features consistent with higher local fracture density. With per-stage processing in seconds and no extra sensing hardware, the method is well suited for near-real-time deployment. Full article

One-way joist slab floor systems are commonly favored in modern residential building applications due to their efficiency in architectural and structural design processes. However, a significant number of such buildings experienced heavy damage or collapse mechanisms during the catastrophic earthquakes in Türkiye since they are more vulnerable due to some uncertainties in the design and construction stages. In this regard, although well-known seismic codes such as Eurocode, IBC, and ASCE do not impose additional requirements for the design of structural systems with joist slabs, the seismic codes of some Mediterranean basin countries regulate the ductility levels, use of shear walls, and member/system-based specific requirements. In the present study, the impact of shear wall quantity on the seismic behavior of reinforced concrete buildings with one-way joist slabs was investigated in five-story structural systems, which were basically similar in terms of the slab properties and layout but have different overturning moment ratios (α_M = 0.75, 0.60, 0.45, 0). In this context, a total of 88 bi-directional nonlinear time history analyses were conducted on four structural systems, which were highly representative of buildings in the earthquake zones of Türkiye, under real earthquake ground motions. Hence, the seismic behavior demands—including story displacement, inter-story drift and plastic deformations, distributions of plastic hinges, and member-based performance levels—were discussed by the overturning moment ratio that is directly associated with the shear wall quantity in the system. It can be concluded that when these buildings are jointly designed with the shear walls and frames of a high ductility level—through the capacity design principles—the stipulated performance objective can be successfully achieved. While the shear wall quantities ranging from 0.45 to 0.75 did not have a significant impact on the member-based damage across all floors, the frame-only system was found to be inadequate for controlling the lateral deformations due to insufficient stiffness under design-based seismic events. Full article

The construction industry is one of the primary global contributors to carbon emissions, with both construction materials and operational energy recognized as critical factors in achieving net-zero goals. Given that structural systems are embodied carbon-intensive, significant early-stage carbon reductions are possible. This paper introduces the dual-layer sustainable optimization framework (DLSOF), a methodology that integrates system-level substitution with span-level optimization and a single life-cycle assessment (LCA) approach focused on embodied carbon (EC) that is applicable to various construction types and climate regions. To validate DLSOF, two representative models of reinforced concrete buildings were selected for analysis: one focused on alternate structural systems and the other on span optimization for a standard slab configuration. The results indicate that, in most cases, span optimization achieves a reduction in embodied carbon of 33%, whilst system-level substitution, in most cases, achieves a reduction of approximately 30%. The dual-layer approach, in comparison to conventional baseline designs, achieves approximately a 52% reduction in embodied carbon. Uncertainty analysis indicates variability in design and data inputs, but the overall trend of embodied carbon reduction remains consistent. The results highlight the critical nature of the early structural design stage. For engineers, the DLSOF provides a practical design pathway, and it offers flexibility to accommodate diverse sustainability goals across varying geographical contexts. This study establishes a replicable and transferable model for low-carbon structural design by systematically integrating design optimization with embodied carbon assessment. Full article

A three-dimensional steady-state thermomechanical contact formulation based on the Boundary Element Method is presented for the analysis of systems involving internal linear heat sources. The formulation consistently couples thermal conduction and thermoelastic contact effects within a boundary integral framework and is suitable for layered configurations governed by interface interactions. The approach is first validated through benchmark problems and subsequently applied to the analysis of a radiant floor system composed of a self-levelling compound and a surface floor covering supported by an elastic foundation. Linear heat sources representative of heating pipes are embedded within the compound layer, and the influence of their vertical position on the thermal and mechanical response of the system is investigated. The results show that the mean surface temperature exhibits an approximately linear dependence on the depth of the heat sources, indicating a high sensitivity of the thermal response to installation parameters. An extended scenario accounting for constrained displacements at the upper edge is also analysed in order to represent more realistic boundary conditions. Under these conditions, partial interface separation induced by thermal expansion leads to a reduction in the heat transferred towards the surface and to lower surface temperature levels. The proposed formulation provides a physically consistent and efficient framework for the analysis of thermomechanical contact problems with localized heat sources, offering an alternative tool for the investigation of layered floor systems and related engineering applications. Full article