1. State of the art methodologies for the estimation of fire costs in buildings to support cost–benefit analysisIkwulono David Unobe, Andrea Lucherini, Shuna Ni, Thomas Gernay, Ranjit Kumar Chaudhary, Ruben Van Coile, 2024, review article Abstract: Fires can lead to costly building damage as well as loss of lives and injuries. Installed to protect buildings from fire, or to limit the damage from such outbreaks, fire protection measures are a common feature in buildings. However, these features come at a cost. Although quite ubiquitous in buildings, the value of these features to private individuals and to society is not fully understood. To understand their value, a cost benefit analysis detailing the costs and benefits of fire protection measures is needed. Carrying out such an analysis requires methods for computing both the cost of these fire protection measures, and losses from fires (including both direct and indirect losses). This study outlines methodologies for evaluating those costs and losses. An exhaustive collection of available data necessary for estimating both costs and losses is presented. Several limitations in current methodologies and data constraints were identified, with recommendations proposed to address these shortcomings. Relevant sections of a study by the authors that refines fire protection cost estimation at national and sub-national levels are emphasized, including updated building categories, guidance on computing multipliers, and detailed cost calculation methods for installation and maintenance costs. The calculation uses regularly updated U.S. Census Bureau construction data, ensuring timely multiplier updates. The insights and suggestions presented in this study will ultimately refine the process of selecting fire protection strategies that maximize the net benefit of fire protection measures for both private stakeholders and society at large.
Keywords: fire protection measures, cost of fire protection, losses from fire, cost benefit analysis, installation costs, maintenance costs
Published in DiRROS: 18.04.2024; Views: 57; Downloads: 6
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2. Why are the Early Gothic murals in St. Jacob’s Church in Ormož, Slovenia, almost entirely black?Anabelle Križnar, Katja Kavkler, Sabina Dolenec, 2024, original scientific article Abstract: In St. Jacob’s parish church in Ormož, Slovenia, mural paintings from around 1350–1370 are partially conserved in the northeastern corner of the main nave. They are almost completely black, indicating a large-scale pigment degradation. They were studied as a part of a larger research project aiming to identify materials applied and their possible degradation. First, they were studied in situ, and next, extracted samples of plaster, pigments, and colour layers were analysed by optical microscopy, Raman spectroscopy, FTIR spectroscopy, SEM-EDS, and XRD. Haematite, green earth, malachite, azurite, and tenorite were identified, showing that azurite and perhaps also malachite degraded to black tenorite, probably due to their fine grinding and their application directly on the fresh plaster. The plaster is made with small and large amounts of aggregate with mostly quartz with some impurities, which makes it fragile. The original appearance of these murals was of bright blue and green colours.
Keywords: mural painting, medieval painting, Gothic art, St. Jacob's Church, Ormož, Slovenia, pigments, chemical structure, colour degradation, optical microscopy, Raman microspectroscopy, FTIR, XRD
Published in DiRROS: 17.04.2024; Views: 38; Downloads: 12
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3. Modelling intumescent coatings for the fire protection of structural systems : a reviewAndrea Lucherini, Donatella de Silva, 2024, review article Abstract: Purpose
Intumescent coatings are nowadays a dominant passive system used to protect structural materials in case of fire. Due to their reactive swelling behaviour, intumescent coatings are particularly complex materials to be modelled and predicted, which can be extremely useful especially for performance-based fire safety designs. In addition, many parameters influence their performance, and this challenges the definition and quantification of their material properties. Several approaches and models of various complexities are proposed in the literature, and they are reviewed and analysed in a critical literature review.
Design/methodology/approach
Analytical, finite-difference and finite-element methods for modelling intumescent coatings are compared, followed by the definition and quantification of the main physical, thermal, and optical properties of intumescent coatings: swelled thickness, thermal conductivity and resistance, density, specific heat capacity, and emissivity/absorptivity.
Findings
The study highlights the scarce consideration of key influencing factors on the material properties, and the tendency to simplify the problem into effective thermo-physical properties, such as effective thermal conductivity. As a conclusion, the literature review underlines the lack of homogenisation of modelling approaches and material properties, as well as the need for a universal modelling method that can generally simulate the performance of intumescent coatings, combine the large amount of published experimental data, and reliably produce fire-safe performance-based designs.
Research limitations/implications
Due to their limited applicability, high complexity and little comparability, the presented literature review does not focus on analysing and comparing different multi-component models, constituted of many model-specific input parameters. On the contrary, the presented literature review compares various approaches, models and thermo-physical properties which primarily focusses on solving the heat transfer problem through swelling intumescent systems.
Originality/value
The presented literature review analyses and discusses the various modelling approaches to describe and predict the behaviour of swelling intumescent coatings as fire protection for structural materials. Due to the vast variety of available commercial products and potential testing conditions, these data are rarely compared and combined to achieve an overall understanding on the response of intumescent coatings as fire protection measure. The study highlights the lack of information and homogenisation of various modelling approaches, and it underlines the research needs about several aspects related to the intumescent coating behaviour modelling, also providing some useful suggestions for future studies.
Keywords: intumescent coatings, fire protection, modelling, structural fire engineering, fire safety, performance-based design
Published in DiRROS: 17.04.2024; Views: 54; Downloads: 14
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4. Experimental investigation of the shear force capacity of prismatic cross laminated timber beamsHenrik Danielsson, Tomaž Pazlar, Erik Serrano, Boris Azinović, 2024, original scientific article Abstract: Experimental tests of Cross Laminated Timber (CLT) under in-plane beam loading conditions are presented. The influence of the element layup, the individual lamination width, and the beam overhang at the supports on the shear force capacity was investigated. All the CLT beams had the same gross cross section, and a 4-point-bending test setup was used. The experimentally determined load-bearing capacities are compared with the load-bearing capacities resulting from analytical methods proposed for structural design, focusing on shear failure in the crossing areas of flatwise bonded laminations (shear failure mode III). The test results indicate no or very small influence of the element layup and the lamination width on the shear force capacity. These results partly contradict the predictions of the proposed design methods. Of the three studied beam geometry parameters, the beam overhang at the support had the greatest influence on the load-bearing capacity.
Keywords: cross laminated timber, CLT, beam, shear testing, shear capacity, design methods
Published in DiRROS: 15.04.2024; Views: 70; Downloads: 33
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5. Thermal characterisation of the cooling phase of post-flashover compartment firesAndrea Lucherini, Balša Jovanović, Jose L. Torero, Ruben Van Coile, Bart Merci, 2024, original scientific article Abstract: The main characteristics of the cooling phase of post-flashover compartment fires are studied using a simplified first-principles heat transfer approach to establish key limitations of more traditional methodologies (e.g., Eurocode). To this purpose, the boundary conditions during cooling are analysed. To illustrate the importance of a first-principles approach, a detailed review of the literature is presented followed by the presentation of a simplified numerical model. The model is constructed to calculate first-order thermal conditions during the cooling phase. The model is not intended to provide a precise calculation method but rather baseline estimates that incorporate all key thermal inputs and outputs. First, the thermal boundary conditions in the heating phase are approximated with a single (gas) temperature and the Eurocode parametric fire curves, to provide a consistent initial condition for the cooling phase and to be able to compare the traditional approach to the first- principles approach. After fuel burnout, the compartment gases become optically thin and temperatures decay to ambient values, while the compartment solid elements slowly cool down. For simplicity, convective cooling of the compartment linings is estimated using a constant convective heat transfer coefficient and all linings surfaces are assumed to have the same temperature (no net radiative heat exchange). All structural elements are assumed to be thermally thick. While these simplifications introduce quantitative errors, they enable an analytical solution for transient heat conduction in a semi-infinite solid that captures all key heat transfer processes. Comparisons between the results obtained using both approaches highlight how, even when considering the same fire energy input, the thermal boundary conditions according to the Eurocode parametric fire curves lead to an increase energy accumulated in the solid after fuel burnout and a delay in the onset of cooling. This is not physically correct, and it may lead to misrepresentation of the impact of post-flashover fires on structural behaviour.
Keywords: cooling phase, fire decay, fire dynamics, compartment fires, structural fire engineering, fire safety
Published in DiRROS: 15.04.2024; Views: 62; Downloads: 30
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6. An experimental apparatus for bench-scale fire testing using electrical heating padsAleksandra Seweryn, Andrea Lucherini, Jean-Marc Franssen, 2023, original scientific article Abstract: This research study concerns an experimental, budget-friendly, electricity- powered apparatus for bench-scale fire testing. The apparatus consists of various elements, of which the most important are ceramic heating pads, used to impose heat fluxes on exposed surfaces of specimens. The test method allows to control the heating pads’ temperature and to adjust the distance between the heating pads and the specimen to obtain well-defined heat fluxes up to 50–60 kW/m2. Higher heat fluxes and temperatures can be obtained by setting the heating pads in full power mode, with or without the use of a thermal shield, which can lead to heat fluxes up to 150 kW/m2. The heating and thermal boundary conditions imposed by the apparatus are characterised and discussed, and the thickness of the convective boundary layer at the heating pads’ surface is estimated significantly lower than in the case of gas- fired radiant panels. The performance of the apparatus is analysed for various conditions: controlling the temperature of the heating pads, in an open environment or with the presence of thermal shields, and in full power mode. A few examples of application of the apparatus to fire test typical construction materials (steel and glass) are also presented. These results emphasise the well-defined heating conditions in temperature-controlled mode. The study finally discusses the advantages and limitations of the apparatus, as well as many possibilities of future applications and improvement for future research studies.
Keywords: radiant panels, fire testing, heat transfer, heat flux, electrical heating pads, thermal boundary conditions
Published in DiRROS: 15.04.2024; Views: 64; Downloads: 25
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7. Influence of test methodology on the characterization of the parallel-to-grain timber embedment strength and foundation modulus of dowelsCaroline D. Aquino, Rodrigues Leonardo G., Michael Schweigler, Meta Kržan, Zheng Li, Jorge M. Branco, 2024, original scientific article Abstract: A reliable determination of the embedment strength and foundation modulus of timber elements is critical for the design and safety assessment of joints in timber structures. However, the existence of various test configurations for characterising the embedding properties of large diameter steel fasteners in timber elements poses challenges in directly comparing and utilising available test data. This paper aims to provide an insight into the influence of embedment property test methods, comparing experimental results from different test setups within the guidelines of the EN 383 and ASTM D 5764-97a standards for European softwood species, Scots pine wood (Pinus sylvestris) and Norway spruce (Picea abies). In addition to the test guidelines, the thickness of the specimen and the application of the load was evaluated within the protocols. A comprehensive statistical analysis was performed to identify statistically significant differences between the groups evaluated. The results of the analysis revealed disagreement between the standards in the evaluation of the strength of the embedding, highlighting the potential bias inserted by the experimental setup and protocol. Furthermore, it was proven that the thickness of the specimens influences both the embedding strength and the foundation modulus of the wood species tested. Finally, no distinctions were observed between tensile and compressive loading within the guidelines of the EN 383 standard.
Keywords: embedment strength, foundation modulus, dowel-type connections, test methods
Published in DiRROS: 15.04.2024; Views: 62; Downloads: 34
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8. Why geopolymers and alkali-activated materials are key components of a sustainable world : a perspective contributionWaltraud M. Kriven, Cristina Leonelli, John L. Provis, Aldo R. Boccaccini, Cyril Attwell, Vilma Ducman, Claudio Ferone, Sylvie Rossignol, Tero Luukkonen, Jannie S. J. Van Deventer, José V. Emiliano, Jérôme E. Lombardi, 2024, original scientific article Abstract: This perspective article delves into the transformative potential of alkali-activated materials, acid-activated materials, and geopolymers in mitigating climate change and market challenges. To harness the benefits of these materials, a comprehensive strategy is proposed. This strategy aims to integrate these materials into existing construction regulations, facilitate certification, and promote market access. Emphasizing research and innovation, the article advocates for, increased funding to refine the chemistry and production of these materials, prioritizing low-cost alternatives and local waste materials. Collaboration between academia and industry is encouraged to expedite technological advances and broaden applications. This article also underscores the need to develop economic and business models emphasizing the long-term benefits of these materials, including lower life-cycle costs and reduced environmental impact. Incentivizing adoption through financial mechanisms like tax credits and subsidies is suggested. The strategy also includes scaling up production technology, fostering industrial collaboration for commercial viability, and developing global supply chains. Educational programs for professionals and regulators are recommended to enhance awareness and adoption. Additionally, comprehensive life-cycle assessments are proposed to demonstrate environmental benefits. The strategy culminates in expanding the applications of these materials beyond construction, fostering international collaboration for knowledge sharing, and thus positioning these materials as essential for sustainable construction and climate change mitigation.
Keywords: geopolymers, alkali activated materials, perspective
Published in DiRROS: 15.04.2024; Views: 72; Downloads: 38
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9. Utilisation of reused steel and slag : analysing the circular economy benefits through three case studiesGenesis Camila Cervantes Puma, Adriana Salles, Janez Turk, Viorel Ungureanu, Luís Bragança, 2024, review article Abstract: This research explores sustainable construction practices focusing on material reuse, specifically reclaimed structural steel and slag. In general, the building stock is not designed for deconstruction, and material recovery for reuse at the end of life of buildings is complex and challenging. The study evaluates the benefits of content reuse through a thorough analysis of three case studies— BedZED eco-friendly housing, Angus Technopôle building, and the use of steel slag aggregate in road construction. It highlights the value of reclaimed structural steel and by-products like steel slag in waste reduction, energy conservation, and resource preservation. The BedZED case study showcases recycled steel’s cost-effectiveness and economic viability in construction, while the Angus Technopôle building exemplifies the adaptive reuse of an old steel frame building. Additionally, the third case study showcases the benefits of using Electric Arc Furnace C slag in asphalt-wearing courses, highlighting the reduction in greenhouse gas emissions and environmental impact. The versatility of reclaimed structural steel and slag is evident in integrating material reuse in building construction and road infrastructure. These case studies illustrate the potential for reusing steel and its by-products in various construction contexts, from eco-friendly housing to road development. Therefore, the study aims to demonstrate the feasibility and benefits of sustainable practices within the construction industry by showcasing the successful incorporation of reclaimed steel and slag in these projects. Considering the significant contributions of building construction to global greenhouse gas emissions, raw material extraction, and waste production, the study advocates for adopting circular economy (CE) principles within the construction industry. Finally, the analysis of case studies underscores the advantages of reclaimed structural steel and the valorisation of steel slag through the lens of CE and their contribution to sustainable development.
Keywords: circular economy, reused steel, steel slag aggregate, reclaimed steel, steel members
Published in DiRROS: 12.04.2024; Views: 86; Downloads: 34
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10. Behaviour of the backfilled right bank of the Mavčiče damPavel Žvanut, Rude Brinšek, 2018, published scientific conference contribution Abstract: The Mavčiče concrete gravity dam, part of the corresponding hydro-power plant, was built on the Sava River, in Slovenia, in 1986. It has a maximum structural height of 38.5 m, and the dam crest has a length of 149 m. The dam structure consists of an erection bay, a machine hall, and two spillways, followed by an embankment dam. Most of the dam is founded on permeable Quaternary conglomerate bedrock, so that a cut-off grout curtain had to be constructed to a depth of up to 60 m below the ground surface, where a layer of impermeable Oligocene marine clay occurs. However, the erection bay, which is located on the right bank of the dam, is founded on a layer of gravel backfill, up to about 25 m thick, which lies on top of the conglomerate bedrock. Long-term manual technical monitoring of the behaviour of the dam began in 1986, and an automated monitoring system was established between 2003 and 2005. In general, the results of measurements and visual inspections did not show any abnormalities. However, this was not the case for the erection bay located on the top of the backfilled right bank of the dam, where the results of measurements of vertical displacements showed increasing settlements. By 1999, i.e. over a period of 12 years, these settlements had increased to 22 mm. The results of investigations, by drilling three research boreholes in 1993, and another six such boreholes in 1996, indicated that the settlements were the consequence of the secondary consolidation of the backfill, and probable also due to scouring of fine material from the backfill. Due to the resulting differential settlements, the crane rail which connects the erection bay to the machine hall, as well as the crane rail which is located along the crest of the dam, became nonfunctional, and needed height corrections. For this reason rehabilitation works of the backfill and of the substratum of the right bank of the dam were performed between September 1999 and August 2000, using 50 m long grouted boreholes. This grouting was performed using a combination of water reactive polyurethane and a cement-bentonite mixture. Measurements performed since than have shown that the settlement rate has slowed down slightly (by 2017, i.e. over the last 17 years, the settlements had increased by up to 8 mm), but from the point of view of the operation of the two crane rails the settlement process needed to be stopped. Additional investigations, involving the drilling of two research boreholes, as well as appropriate laboratory and field measurements, were performed between November 2015 and March 2016. According to the results of these most recent investigations, the newer settlements were the consequence of additional scouring of fine material from the backfill. In order to achieve a final solution to the problem of the subsidence of the erection bay, additional rehabilitation works of the backfill and substratum of the right bank of the dam, by grouting the permeable zones, would be needed in order to stop both the scouring of fine material from the backfill, as well as any internal erosion of the cavernous conglomerate at the base of the backfill. The latter concerns the long-term stability of the right bank of the dam with potentially serious results.
Keywords: concrete dams, gravity dams, Mavčiče Dam, Sava River, technical monitoring, geotechnical investigation, rehabilitation
Published in DiRROS: 05.04.2024; Views: 58; Downloads: 31
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