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In order to maintain the quality of construction for nearly zero energy buildings and to reduce the pressure on construction workers with the addition of the need for faster and simpler structures, the use of cavity-insulated LSF (lightweight steel frame) panels is increasing. Requirements for performance quality, quality of life, and low energy co...
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... [10] demonstrated the application of BIM for energy analysis and sustainability assessment in Portuguese buildings and showed how it can modernize the assessment of energy performance and support sustainable building practices. Similarly, Tkalčić et al. [11] investigated different insulation materials and configurations, such as Lightweight Steel Frame (LSF) walls with a 6-m span, demonstrating reductions of up to 67 % in heat transfer losses when optimized thermal bridge designs were employed. These findings underline the importance of detailed and accurate thermal bridge analysis in achieving nZEB and ZEB goals. ...
... Santos et al. [19,20] demonstrated that optimized configurations of LSF walls and detailed analyses are critical for achieving accurate energy efficiency assessments. Tkalčić et al. [11] showed that the use of advanced materials and design strategies, such as PVC spacers, can reduce heat transfer losses by up to 67 % in extreme cases. These findings highlight the importance of effective thermal bridge management in achieving energy-efficient building designs. ...
Thermal bridges have a significant impact on the energy efficiency of buildings, but their accurate assessment remains a challenge. In this paper, a novel method for estimating the Ψ-values of thermal bridges and their contribution to the transmission heat losses (Htr,TB) is proposed to solve this problem. The proposed method involves calculating the total heat flux across the building cross-sections and subtracting the 1D heat flux of the individual components to derive the Ψ-values. Horizontal and vertical cross-sections are extracted from a 3D BIM (Building Information Modelling) model in Archicad. Numerical simulations are carried out on these cross-sections, which represent the entire building envelope. The method was validated on two buildings: a simple building and a complex multi-part building. The results show that with only three cross-sections (one horizontal and two vertical) Htr,TB can be estimated with less than 2 % error compared to the standard numerical analysis method defined in EN ISO 10211, where each thermal bridge is calculated individually. The proposed method is faster and eliminates the need for manual identification and measurement of thermal bridges. This simplified approach achieves equivalent accuracy and is particularly beneficial for smaller projects. The study emphasises the potential of using BIM tools for practical, efficient thermal bridge analysis.
... With the rapid development of modern transportation, steel structure bridges have gained popularity due to their lightweight, strong crossing capacity, and high construction cycle utilization rate [1][2][3][4]. They are widely used in the construction of modern highways, railways, and urban road bridges [5][6][7]. ...
With increasing traffic loads and extended bridge service life, fatigue damage in steel bridge decks has become a significant concern. Traditional detection methods often lack the accuracy and responsiveness needed for practical engineering applications. To address the non-stationary nature of acoustic emission (AE) signals during crack initiation and propagation, this study combines the K-singular value decomposition (K-SVD) dictionary learning algorithm with convolutional neural networks (CNN) to enhance AE signal processing and fatigue crack detection. The K-SVD algorithm functions as an adaptive filter, learning from AE signals in various damage states to remove background noise and retain critical structural characteristics. This processed AE data is then input into a CNN, where the improved signal clarity enables higher classification accuracy. Specifically, the integration of K-SVD with CNN achieved recognition accuracies of 93.64% and 92.56% for AE signals from damaged areas, and 95.32% and 94.27% for undamaged signals, on training and test sets, respectively. This approach demonstrates strong engineering potential by providing a scalable solution for real-time, accurate crack detection in bridge inspections. Though computationally intensive, K-SVD’s adaptive dictionary learning enhances CNN performance, making the combination viable with optimization strategies in practical settings. These results provide a theoretical foundation and practical guidance for improving fatigue crack detection in steel bridge decks, supporting future applications in automated bridge inspection.
... Schild [48] justifies this method by suggesting that the overall window U-value can be approximated by calculating a simplified model. This model would consist of blocks with equivalent thickness to the actual window frame, assigned a thermal resistance (R -value) identical to the real window's glazing [49]. Figure 17 to Figure 31 show temperature distribution, minimal surface temperature location, U-values and dimensions used for Ψvalue calculation for detail variations corresponding to the Figure 2 to Figure 16. ...
This study investigates mould/fungi growth risk on two different approaches of thermal bridge mitigation. Thermally insulated balconies and thermally broken balconies in Zero Emission Building (ZEB) are reviewed. Linear thermal transmittance (ψ - value), interior surface temperature and mould/fungi growth risk for five balcony designs is performed. Each design has three variations, two of which have thermal insulation wrap, and a thermal break replacing insulation. Results show thermal breaks outperform all variations. This contradicts the common practice of using thermal insulation wrap. The study also emphasizes EN ISO 13788 inadequacy as comprehensive HAM models are available.
... The initial reliance on standard catalog items has transitioned to custom calculated solutions, emphasizing the need for accurate thermal performance assessments. Previous evidence suggests that thermal bridges significantly impact energy efficiency and can lead to increased heat loss, structural damage, and condensation risk [46,47]. Advanced systems incorporating thermal spacers have been shown to effectively reduce these effects, with studies demonstrating that optimized designs can reduce transmission heat losses by up to 67% [47]. ...
... Previous evidence suggests that thermal bridges significantly impact energy efficiency and can lead to increased heat loss, structural damage, and condensation risk [46,47]. Advanced systems incorporating thermal spacers have been shown to effectively reduce these effects, with studies demonstrating that optimized designs can reduce transmission heat losses by up to 67% [47]. In addition, integrated computational methods for identifying dynamic thermal bridging allow for better design decisions at the conceptual stage, thereby improving the overall thermal performance of building facades [48]. ...
... Figure A13 in Appendix B visually supports this analysis by illustrating the structural aspects of the reinforced concrete framework that supports the ventilated stone facade, emphasizing allowances for vertical deviations to ensure proper alignment and functionality despite variations in the concrete structure. Such considerations are vital for maintaining the integrity and thermal performance of the stone facade system, as structural misalignments can lead to significant energy losses and compromise the overall effectiveness of the design [46,47]. ...
The rationale for this work arose from the urgency of improving the energy efficiency of buildings at the design stage, given the changing requirements of energy efficiency standards such as the Polish Technical Conditions (WT 2014 and WT 2020). This research is novel as there is currently limited information available on the improvement of the thermal performance of ventilated stone facade systems, although they are now widely used due to their practical and aesthetic advantages. The first objective of this work is to evaluate the thermal performance of the ventilated facades of the Praski Student House (Akademik Praski) and to assess how certain design variations can help achieve a lower level of energy consumption. Using a comprehensive case study approach, this study provides accurate thermal calculations of the facade to assess its global thermal insulation coefficient (Rt) and thermal transmittance (Uc). The improvement in the actual U-value from the original design is as follows: the U-value is reduced from 0.33 originally to 0.228 for WT 2014 and to 0.198 for WT 2020, showing a reduction of about 30.9% and 13.2%, respectively. These results indicate the energy efficiency of increased insulation thickness and optimally oriented air gap dimensions. The practical contributions of this research are valuable for architects, engineers, and contractors involved in the design and construction process of buildings aiming to achieve near-zero energy buildings (nZEBs), including concrete suggestions on how to improve current construction practices as well as material recommendations. There is a need for durability studies, for example to assess the performance of such facades under different climatic conditions, as part of future work to support these findings.
... Option 8 incorporates various energy-saving technologies, including exterior wall insulation, window thermal insulation, and roof insulation optimization. This composite structure has been demonstrated to effectively reduce thermal bridging and heat transfer, corroborating previous research findings on the efficacy of such integrated approaches (Chandhran & Elavenil, 2023;Tkalčić et al., 2023). In summary, this study confirms the proposed framework's feasibility and effectiveness through rigorous theoretical analysis and detailed case studies. ...
The construction industry’s rapid growth significantly impacts energy consumption and environmental health. It is crucial to develop optimization strategies to enhance green building energy efficiency and encompass comprehensive analysis methods. This study aims to introduce and validate a novel framework for optimizing energy efficiency design in green buildings by integrating Building Information Modeling (BIM) technology, Life Cycle Cost (LCC) analysis, and orthogonal testing methods, focusing on enhancing energy efficiency and reducing life cycle costs. The optimization parameters for the building envelope are identified by analyzing energy consumption components and key green building factors. The orthogonal testing method was applied to streamline design options. Building Energy Consumption Simulation (BECS) software and LCC analysis tools were employed to calculate each optimized option’s total annual energy consumption and the current life cycle costs. Using the efficiency coefficient method, each optimization scheme’s energy consumption and economic indicators were thoroughly analyzed. The framework’s validity and applicability were confirmed through an empirical analysis of a campus green building case in Fujian Province, demonstrating that the optimized framework could reduce energy consumption by 4.85 kWh/m2 per year and lower costs by 38.89 Yuan/m2 compared to the reference building. The case study highlights the framework’s significant benefits in enhancing environmental performance and economic gains. The results provide critical parameter selection and offer scientific and technological support for the design of building energy efficiency, promoting optimization techniques and sustainable development within the construction industry.
... Kao rješenje sve je popularnija upotreba LSF (lagani čelični okvir) panela s toplinskom izolacijom u šupljinama. Zbog strogih zahtjeva vezanih uz potrošnju energije za grijanje i hlađenje zgrada, šupljine se ne ostavljaju praznima, nego se najčešće ispunjavaju mineralnom vunom [1]. Sve je češća primjena alternativnih pristupa u građevinskome sektoru kao što je korištenje metalnih umjesto betonskih ili zidanih konstrukcija. ...
... Gotovi paneli dostavljaju se na gradilište te su odmah spremni za ugradnju. Paneli se međusobno spajaju vijčanom vezom, što omogućuje brzu ugradnju na gradilištu [1]. U usporedbi s klasičnom LSF konstrukcijom, KLIK panel zahtijeva detaljnije projektiranje provođenja instalacija jer se radi o predgotovljenoj gradnji koja nije fleksibilna po pitanju naknadnih modifikacija panela na gradilištu ili adaptacija tijekom životnog ciklusa. ...
21. do 24. travnja 2024 · Cavtat Hrvatski savez građevinskih inženjera 513 9. Sabor hrvatskih graditelja Sažetak U ovome radu provedena je numerička analiza prijenosa topline s optimiranjem toplinskih mosto-va za LSF (engl. Light Steel Frame) šuplje izolirane zidove kako bi se smanjili ukupni gubici topline kondukcijom. Analizirani su učinci izolacijskih materijala šupljina (mineralne vune i poliuretanske pjene) i utjecaj distancera između čeličnih nosača i obloga. Na kraju, dodatni slojevi izolacije dodani su na unutarnju i vanjsku stranu LFS panela kako bi se minimizirao učinak toplinskih mostova i maksimirala zrakonepropusnost. Abstract This paper presents a numerical analysis of heat transfer with thermal bridging optimization for LSF (Light Steel Frame) hollow insulated walls to reduce overall heat losses by conduction. Effects of insulation materials (mineral wool and polyurethane foam) and the influence of spacers between steel studs and cladding were analyzed. Additionally, extra insulation layers were added to the inner and outer sides of LSF panels to minimize thermal bridging effects and maximize air tightness.
Energy efficiency and waste management are crucial for sustainability of construction sector. In this research, a new gypsum composite material is presented in which traditional raw materials have been partially replaced by thermal insulation waste from facades energy retrofitting projects, using an innovative process to recover this waste. Consequently, a novel lightweight gypsum composite has been developed with a replacement of up to 14.7 % by weight of the original material with EPS waste, adding mineral wool as reinforcement fibres (0.375 % wt.). Thus, thermal behaviour analysis of these new composites has been conducted, both material itself and of its performance as part of a real construction system, including finite element analysis of the construction system. In addition, the physicochemical, physical and mechanical characterisation of the new composites has been carried out. Results show that the developed new material has a density 20.3 % lower than the traditional gypsum composite, resulting in a 30.4 % reduction in thermal conductivity. Furthermore, the use of these new lightened gypsum composites as finishing boards in lightweight steel frame (LSF) wall systems reduces the overall thermal resistance of the wall by up to 10.6 % with just 25 mm thickness. On the other hand, the me- chanical resistance of this new material exceeds the reference values established by current standards, ranging between 4.18 and 1.87 MPa for flexural strength and between 7.87 and 4.27 MPa for compressive stresses. Additionally, the developed composites have shown a reduction in both total and capillary water absorption compared to traditional gypsum by 19.6 % and 40.0 % respectively, enhancing the material’s durability and its excellent thermal properties throughout its lifespan.
