Search Results (320)

Fully volumetric modular mining structures offer a partial solution to achieving sustainable construction at remote mine sites. Significant logistical challenges arise during road and sea transportation, depending on the size of the prefabricated modules and the remoteness of the site. As an alternative, hybrid modular mining structures comprising various non-volumetric prefabricated components of transportable size, assembled on-site to form complete structures, have previously been proposed. To facilitate hybrid modular structures in the mining industry, the paper reviews the design actions to which mining structures are subjected and evaluates the corresponding structural responses. It also examines existing connections that may be suitable for the hybrid module structures, assessing their effectiveness and safety in connecting prefabricated structural components. Finally, key requirements for connection design are identified to facilitate hybrid assembly. Full article

Prefabricated steel structures have been increasingly adopted in modern construction due to their high efficiency, sustainability, and industrialized production. However, their construction quality and efficiency are often compromised by accumulated geometric deviations during fabrication, transportation, assembly, and welding, while traditional construction control and welding processes remain highly dependent on manual measurements and empirical operations. To address these challenges, this study proposes a digital construction framework for prefabricated steel structures, integrating high-precision three-dimensional (3D) laser scanning, Building Information Modeling (BIM), and intelligent welding technologies. First, high-precision 3D laser scanning is employed to capture the as-built geometric information of prefabricated steel components, generating dense point cloud data for construction-stage deviation detection and quantitative comparison with BIM-based design models. Based on deviation analysis, a digital construction control strategy is established to support real-time feedback, error compensation, and assembly adjustment. An engineering case study involving a complex prefabricated steel structure is conducted to validate the proposed framework. The results demonstrate that the integrated digital construction and intelligent welding approach significantly improves assembly accuracy, weld positioning precision, and construction efficiency, while reducing manual intervention and error accumulation. Overall, this study contributes to the body of knowledge by proposing a unified closed-loop digital construction paradigm that integrates geometric perception, deviation-driven decision-making, and intelligent welding execution, thereby bridging the gap between construction control and robotic fabrication in prefabricated steel structures. Full article

Existing studies conduct general cost analyses for prefabricated components, yet structural heterogeneity results in distinct cost drivers. Most studies concentrate on the technical performance of prefabricated staircases, with insufficient investigation into dedicated cost-estimation methods. This study establishes a hybrid prediction framework integrating GAN-based data augmentation and SHAP-empowered Multilayer Perceptron (SHAP-MLP) modeling, using prefabricated straight staircases as empirical objects for multidimensional analysis. Total cost is classified into production, transportation, and on-site installation phases, followed by systematic screening of 33 influencing factors for predictive modeling. The Analytic Hierarchy Process (AHP), with a 1–9 scale, is adopted to quantify indicator weights and prioritize features. Triple verification (multi-expert consistency test, group opinion coordination test, and sensitivity analysis) removes five weakly correlated parameters to form a preliminary indicator system. Based on 240 original engineering data samples, the GAN generates 60 high-fidelity synthetic samples. Distribution consistency between synthetic and original data is validated via the Kolmogorov–Smirnov (KS) test, p-value verification, and kernel density estimation (KDE). SHAP interpretability analysis identifies four core determinants: prefabrication rate, total staircase area, standardization level, and number of floors. Eight low-impact parameters are excluded to optimize model input, leaving 20 validated indicators. The GAN-SHAP-MLP model maintains superior performance in testing, with a test-set RMSE of 49.538, representing improvements of 41.3%, 22.5%, and 25.7% over LSTM (89.33), CNN (67.59), and standard MLP (70.56), respectively. The difference between its test-set and overall R² is only 0.69%, significantly lower than 2.06% for LSTM and 5.47% for MLP. Empirical validation with real engineering cases from four different regions further confirms the model’s high prediction accuracy, with a minimum error of only 1.49%. The integration of data augmentation and interpretable deep learning provides a high-precision, interpretable cost prediction tool for prefabricated straight staircases, promoting methodological progress in construction economics. Full article

The mechanical performance of joints in prefabricated subway stations is a key factor governing the overall structural stability. This study investigates the grouted mortise–tenon joint (GMTJ), which is widely used in prefabricated subway station structures. A refined finite element model was established by incorporating material nonlinearity and a cohesive–friction hybrid constitutive model for the grout–concrete interface, and the accuracy of the model was validated against experimental results. Using the prototype GMTJ from an engineering project as the baseline, parametric analyses were conducted considering three concrete strength grades (CSGs) and three longitudinal reinforcement ratios (LRRs). The results show that increasing the CSG improves the joint’s flexural capacity and delays crack propagation. Although a higher LRR enhances the overall deformation resistance, an excessively high LRR intensifies stress concentration in the tenon region due to the absence of reinforcement in this area. Therefore, merely increasing the LRR cannot effectively improve joint durability, and local reinforcement of critical components such as the tenon is recommended in practical engineering. These findings provide meaningful references and insights for the structural design of prefabricated subway station joints. Full article

With the vigorous promotion of the modernization of China’s construction industry, the proportion of prefabricated buildings in new construction projects has increased steadily. Grouted sleeve connection is a mainstream joining method for prefabricated components, and the performance of grouting materials is crucial to connection reliability. In this study, a modified polyurethane composite (MPC) was developed as a novel sleeve grouting material, and seven grouted splice specimens with different steel bar strength grades and anchorage lengths were fabricated for uniaxial tensile tests. The mechanical properties of MPC and the connection performance of specimens were systematically investigated, and the effects of steel bar strength grade and anchorage length on ultimate load, average bond strength, and strain characteristics were quantitatively analyzed. The results show that MPC has excellent fluidity, and its mechanical strengths meet the specified requirements. Increasing steel bar strength grade and anchorage length significantly improves ultimate load: at a 6d anchorage length, the ultimate load of the S600 series (HRB600E) is 44.85% higher than that of the S400 series (HRB400E); extending the S400 series’ anchorage length from 4d to 8d increases ultimate load by 50.61%. Average bond strength decreases with increasing anchorage length (S400-MPC-8d is 24.70% lower than S400-MPC-4d) but increases with higher steel bar strength grade (S600-MPC-6d is 32.37% higher than S400-MPC-6d). The sleeve remains elastic during the test, ensuring safety. Prediction formulas for average bond strength under slip failure were established, with good agreement between predicted and experimental results. For both HRB400E and HTRB600E steel bars, considering safety and installation errors, a critical anchorage length of 8d is recommended for engineering design. Full article

Precast concrete (PC) component production scheduling is essential to the efficiency and reliability of industrialized construction. Although intelligent algorithms have been widely applied in this field, the relationships among research evolution, collaboration patterns, and industrial applicability remain insufficiently understood. To address this issue, this study presents a bibliometric review of 1272 publications indexed in the Web of Science Core Collection from 1990 to 2025. CiteSpace was employed to analyze publication trends, collaboration networks, co-citation structures, keyword co-occurrence, and burst terms. On this basis, a technology adaptability evaluation framework was developed to assess the alignment between algorithmic advances and industrial implementation in terms of dynamic adaptability, verification completeness, and technological generation gap. The results indicate that the field has evolved through four broad stages, from early static optimization to multi-objective coordination, digital twin-enabled dynamic scheduling, and emerging human-centric intelligent autonomous systems. The analysis also shows an increasing convergence of operations research, computer science, and civil engineering. However, a gap remains between academic output and industrial application. Specifically, 32% of the retrieved studies focused on genetic algorithms, whereas only 6% reported full-process industrial validation. In addition, Gen 4.0-related studies showed a technological generation gap of 82.5%, indicating that many frontier technologies have not yet reached broad industrial implementation. The collaboration network further reveals a “high-output, low-synergy” pattern, in which major publishing countries contribute substantially to the literature but exhibit limited cross-institutional integration. This study provides a structured overview of the development of PC component production scheduling research and highlights future directions for digital twin integration, human–robot collaboration, and cross-sector validation platforms. Full article

Gypsum-based materials are widely used in construction but suffer from poor water resistance and durability, limiting their application in moisture-prone environments. While fiber-reinforced modified gypsum (FRMG) improves mechanical performance, the lack of systematic research on waterproofing strategies and their influence on both durability and strength remains a key challenge. This study investigated three waterproofing methods: surface coating with paraffin emulsion, internal incorporation of paraffin emulsion, and internal incorporation of vinyl acetate ethylene (VAE) emulsion. The workability, water absorption, mechanical properties, contact angle, and microstructure of the FRMG matrix were analyzed. The results showed that surface coating provided only short-term waterproofing. Internal incorporation of paraffin emulsion reduced water absorption but weakened mechanical performance. In contrast, VAE emulsion formed continuous polymer films that filled pores, significantly reducing water absorption while improving flexural and compressive strength, with optimal performance observed at a 6% dosage. In addition, increasing emulsion content enhanced hydrophobicity. These results indicate that VAE-based internal modification is an effective approach to improving the durability and performance of gypsum-based materials, providing guidance for their application in interior wall systems and prefabricated building components. Full article

In response to escalating global environmental challenges, mitigating carbon emissions in the construction sector has emerged as a critical strategy for addressing climate change. As reported by the United Nations Environment Programme (UNEP) and the International Energy Agency (IEA), the construction industry remains a major contributor to global greenhouse gas emissions. This study investigates the influencing factors and optimization pathways for embodied carbon emissions during the materialization phase of prefabricated buildings. Through longitudinal field research at a large-scale precast component factory in western China, key carbon emission factors were identified using Min–Max normalization and Principal-Components Analysis (PCA). A cloud entropy–based evaluation model was further developed to quantify the emission weights of 32 factors. The results reveal the existence of ‘leveraging effects’ among emission factors, wherein certain low-weight factors exert disproportionate influence on systemic carbon reduction because of their cascading impacts on other variables. Prioritizing factors with greater leveraging potential is imperative for the formulation of effective emission reduction policies. This study leverages NK model simulations (10,000 iterations), to predict the reduction potential of each factor and identifies four indicators with the most significant leveraging effects. Strategic recommendations are proposed that emphasize a synergistic approach that integrates direct emission control and indirect cascading optimization. These findings provide actionable insights for achieving systemic carbon reduction in prefabricated building systems. Full article

To address the challenges encountered during the in situ welding reinforcement process of hollow spherical joints, including complex construction, limited quality control, and low efficiency, this study proposed a prefabricated reinforced hollow spherical joint. A three-dimensional finite element (FE) model was developed and validated against experimental results to quantify the effects of T-rib web width (b), web thickness (t₁), ferrule thickness (t₂), hollow-sphere diameter (D), and bolt pretension (f_v) on the bearing capacity of the prefabricated joint. Based on these analyses, a predictive model was established for the axial compressive bearing capacity of the prefabricated joint. The results showed that, under compression, the reinforcing components primarily provided a supporting role to the hollow sphere, thereby improving the buckling resistance of the prefabricated joint under compression. The reinforcement mechanism primarily relied on friction between the ferrule and the steel stub for load transfer, with the available frictional resistance governed primarily by bolt pretension and the stiffness of the reinforcing components. When sufficient friction existed between the ferrule and the steel tube, increasing the T-rib web width from 0 mm to 80 mm improved the bearing capacity of the prefabricated joint by 33%. At a T-rib flange height (h)-to-web width ratio of h/b = 1.0, the T-rib satisfied the reinforcement requirement through its inherent strength and stiffness. As the hollow-sphere diameter-to-thickness ratio decreased, the incremental gain in bearing capacity diminished. A predictive model was proposed for compressive bearing capacity by accounting for the support provided by the reinforcing components and the effects of hollow-sphere diameter, steel-tube diameter, and the tube-to-sphere diameter ratio. The proposed model predicted the FE results with errors within ±10%, and the findings can provide a practical reference for designing the compressive bearing capacity of prefabricated reinforced hollow spherical joints. Full article

The built environment in the EU accounts for 40% of the total energy consumption and 36% of the total greenhouse gas emissions. To address the inefficiency of existing buildings, renovation could reduce their total energy consumption by 5–6% and lower carbon dioxide emissions by approximately 5%. A retrofit solution for existing buildings involves the use of lightweight prefabricated systems, some of which include integrated HVAC components that are able to enhance their functionality. Indeed, such prefabricated facade elements with integrated HVAC systems can represent a minimally invasive method for reducing the energy consumption of an existing building. To assess the potential of this approach, a full-scale mock-up of a prefabricated timber facade with integrated HVAC system was tested at the Facade System Interactions Lab (FSIL) of Eurac Research, Bolzano. The experimental data were used to develop a calibrated and validated 3D finite element model in COMSOL Multiphysics. The validated model was used to evaluate the facade’s thermal performance under standard heating conditions through a proposed equivalent thermal transmittance indicator (U_eq). Results show that the active facade achieves 0.07 W m⁻² K⁻¹, compared to 0.21 W m⁻² K⁻¹ for the passive facade with identical materials but without active components. Full article

The geometric dimensional accuracy of large-scale prefabricated components is critical for the successful implementation of prefabricated construction. However, traditional manual contact-based inspection methods are inefficient and are often simplified or even neglected in practice due to operational difficulties. To address this challenge, this study proposes an automated non-contact dimensional inspection system based on UAV photogrammetry. The system consists of three core modules: First, the 3D Model Generation Module utilizes UAV-captured multi-view imagery to rapidly reconstruct high-fidelity 3D models of construction sites using improved 3D Gaussian Splatting technology, while recovering true physical scales by integrating GPS metadata. Second, the Segmentation Module extracts target components from complex backgrounds through flexible target selection and achieves automated planar segmentation using the Region Growing algorithm. Finally, the Dimensional Inspection Module accurately calculates geometric dimensions using a self-developed “Measurement Tree” algorithm. Engineering validation demonstrates that the system achieves an average relative error of only 0.35% in the inspection of prefabricated bent caps, exhibiting excellent measurement accuracy and robustness. This study provides an efficient, precise, and intelligent solution for the quality control of prefabricated components, effectively bridging the gaps inherent in traditional inspection methods. Full article

Background/Objectives: Locally advanced midface malignant tumors require extensive resection, resulting in complex defects involving bone and multiple soft tissue structures. Reconstructing these substantial defects presents a significant challenge to restore both function and aesthetics. This study aims to compare the functional and aesthetic outcomes of chimeric free flaps versus single free flaps in midface microvascular reconstructions. Methods: This retrospective analysis included fifty consecutive patients with Type III Cordeiro defects who underwent midface reconstruction with free tissue transfer between 2020 and 2024. The cohort included fourteen patients who received prefabricated chimeric flaps and thirty-six patients who received single free flaps. Outcomes were assessed six months postoperatively using a modified University of Washington Quality of Life Questionnaire (UW-QOL), analyzing domains including speech, chewing, sensation, appearance, pain, and social activity. Statistical analysis was performed using the Mann–Whitney U test. Results: In the chimeric flap group, no major flap necrosis or complications were observed. In unadjusted comparisons, the chimeric flap group showed higher transformed UW-QOL scores in several domains. Statistically significant between-group differences were observed for opening and speech (p = 0.004), change in appearance (p = 0.022), sensation (p = 0.011), and social activity (p = 0.006). Aesthetic outcomes, assessed via patient rating of appearance, were also significantly higher in unadjusted comparisons with the chimeric flap approach. Furthermore, in Type IIIa defects, titanium mesh successfully provided reliable orbital support. Conclusions: Chimeric free flaps represent a feasible reconstructive option in selected cases of complex maxillary and midface reconstruction. Their main advantages—providing the proper amount of specific, well-vascularized tissue and offering greater mobility of components— may be associated with more favorable functional, aesthetic, and social outcomes in unadjusted comparisons compared to reconstruction using single free flaps. Full article

Precast concrete components, as one of the important structural systems in prefabricated buildings, have received widespread attention due to their efficient manufacturing characteristics on the production line. Their production sequence and layout on the mold table have a crucial impact on production energy consumption. However, a critical constraint is often overlooked in the first step of precast concrete manufacturing: the production sequence and layout of molds are planned without considering the limited availability of molds for each component type. Therefore, this article proposes a mixed-integer programming model for the production sequence and layout of precast concrete components under a limited number of molds, aiming to simultaneously minimize production energy consumption, fluctuation coefficients of mold table utilization, and mold switching time. To obtain high-quality solutions for production sequence and mold layout, a multi-objective genetic flatworm algorithm with a Tabu mapping mechanism is developed to efficiently determine the production sequence and the positions of molds on the mold tables. Through three production cases of precast concrete components with different scales, the proposed model and algorithm have been demonstrated to be highly effective in assisting decision-makers in quickly formulating the optimal production sequence and layout schemes for precast concrete components. Full article

This study designs a novel modular prefabricated concrete foundation for cable termination supports in the power industry. This foundation is composed of prefabricated components including concrete segmented foundations, strut and connector via bolted connections, featuring convenient construction and a reduction of nearly 40% in concrete consumption. The finite element model was established using FEA software (Version ABAQUS 2020), and an economical and stable mesh size was selected through mesh convergence analysis. The settlement and bearing capacity of the foundation under axial compression were analyzed. Results show that this prefabricated foundation remains in the elastic stage under service load, with uniform settlement and excellent integrity. The stress of reinforcement bars and bolts is much lower than the material yield strength, and the concrete has ignorable damage. In addition, the safety margin is sufficient, and the force transfer path is clear. The research results can improve the prefabricated system for power facilities and provide technical support for the green and efficient construction of cable termination support foundations. Full article