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![''Arch jack'' floor (left) and ''filler joist'' construction (right) [1].](profile/Chrysanthos-Maraveas/publication/253650548/figure/fig8/AS:806961192919042@1569405949651/Arch-jack-floor-left-and-filler-joist-construction-right-1.png)
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Context 1
... with encasing the fire-susceptible structural element (metal) within fire-resistant materials (concrete or masonry). In 19th century construction, two types of fireproof flooring systems are typically encountered. In the first type, the ''jack arch floor'', asymmetrical cast iron beams were encased in ''early concrete'' underlain by masonry (Fig. 1, left). The bottom flange would not be encased and would serve as support for the overlaying masonry. The second type, called ''filler joist'', involved pouring the ''early concrete'' slab in such a way that the beams were completely embedded (Fig. 1, right). In the ''filler joist'' construction, however, the beams were made out of wrought ...
Context 2
... floor'', asymmetrical cast iron beams were encased in ''early concrete'' underlain by masonry (Fig. 1, left). The bottom flange would not be encased and would serve as support for the overlaying masonry. The second type, called ''filler joist'', involved pouring the ''early concrete'' slab in such a way that the beams were completely embedded (Fig. 1, right). In the ''filler joist'' construction, however, the beams were made out of wrought iron or mild steel and rarely out of cast iron. In certain cases, the soffit of the cast floor was level with the lower flange of the beam which was, therefore, unprotected. The term ''early concrete'' mentioned above refers to concrete made with various ...
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Citations
... This section includes studies on the thermal and thermomechanical behavior of historic timber (Hasemi et al., 2002b;Garcia-Castillo et al., 2021;Chorlton and Gales, 2019;Zhou et al., 2019;Otto et al., 2017), masonry (Gomez-Heras et al., 2009;Vasanelli et al., 2021;Shao and Shao, 2018;Garrido et al., 2022), and cast iron (Maraveas et al., 2013(Maraveas et al., , 2014(Maraveas et al., , 2015(Maraveas et al., , 2016a(Maraveas et al., , 2016b(Maraveas et al., , 2017 structures, which constitute the majority of the built heritage (Vijay and Gadde, 2021), as well as the performance of restoration mortars (Pachta et al., 2018(Pachta et al., , 2021Demircan et al., 2021) and fire protection coatings for historic structures (Liblik et al., 2021;Chorlton and Gales, 2020;Kielė et al., 2020) at elevated temperatures. Evidently, most of the studies conducted experimental tests (Hasemi et al., 2002b;Garcia-Castillo et al., 2021;Vasanelli et al., 2021;Shao and Shao, 2018;Chorlton and Gales, 2019;Zhou et al., 2019;Otto et al., 2017;Garrido et al., 2022;Maraveas et al., 2015) or are based on the results of experimental tests reported in the literature (Maraveas et al., 2013(Maraveas et al., , 2014(Maraveas et al., , 2016a(Maraveas et al., , 2016b(Maraveas et al., , 2017. ...
... This section includes studies on the thermal and thermomechanical behavior of historic timber (Hasemi et al., 2002b;Garcia-Castillo et al., 2021;Chorlton and Gales, 2019;Zhou et al., 2019;Otto et al., 2017), masonry (Gomez-Heras et al., 2009;Vasanelli et al., 2021;Shao and Shao, 2018;Garrido et al., 2022), and cast iron (Maraveas et al., 2013(Maraveas et al., , 2014(Maraveas et al., , 2015(Maraveas et al., , 2016a(Maraveas et al., , 2016b(Maraveas et al., , 2017 structures, which constitute the majority of the built heritage (Vijay and Gadde, 2021), as well as the performance of restoration mortars (Pachta et al., 2018(Pachta et al., , 2021Demircan et al., 2021) and fire protection coatings for historic structures (Liblik et al., 2021;Chorlton and Gales, 2020;Kielė et al., 2020) at elevated temperatures. Evidently, most of the studies conducted experimental tests (Hasemi et al., 2002b;Garcia-Castillo et al., 2021;Vasanelli et al., 2021;Shao and Shao, 2018;Chorlton and Gales, 2019;Zhou et al., 2019;Otto et al., 2017;Garrido et al., 2022;Maraveas et al., 2015) or are based on the results of experimental tests reported in the literature (Maraveas et al., 2013(Maraveas et al., , 2014(Maraveas et al., , 2016a(Maraveas et al., , 2016b(Maraveas et al., , 2017. ...
... This research is of great relevance since both repealed and current building codes do not provide guidance for fire resistance analysis of these structures. First, Maraveas et al. (2013) gathered from literature the temperature-dependent thermal and mechanical properties of the materials constituting 19th century fireproof flooring systems, i.e. cast iron and associated insulation materials (early concrete or masonry). Note that the term fireproof refers to the use of non-combustible building materials. ...
Heritage and historic buildings possess an important architectural and cultural value which fire significantly threatens. However, current codes very rarely address the peculiarities of such buildings vis-à-vis fire hazards. Therefore, bringing these buildings into compliance with fire safety regulations while avoiding heritage loss is a great challenge. Within this context, this study provides a comprehensive overview of the current state of the art of research on fire in heritage and historic buildings. The analysis of the literature shows that, despite significant advances in research, the fire safety of historic buildings remains alarming, with important research gaps to be addressed. This study identifies these gaps, proposes future research areas, and provides a baseline for the search for solutions to achieve fire safety in heritage and historic buildings. Thus, this work promotes the conservation of these buildings, as well as rehabilitation over demolition and new construction, leading to a more sustainable construction.
... For example, Russo et al. [121] developed a mechanical characterization of stackbond prisms produced with fire-damaged clay bricks extracted from a historic masonry structure that was partially destroyed by a fire accident (Fig. 15b). Although mechanical and thermal properties of masonry units and mortar exposed to elevated temperatures vary considerably and may not be easily determined [130,131], the MDT of field-extracted prisms developed by Russo et al. [121] were able to provide reasonable estimation of the residual compressive strength of the fire-damaged structure. Drougkas et al. [14] tested stack-bond prisms made with cylindrical cores from solid clay units and pure lime mortar. ...
Masonry prisms have been widely used in research and quality control of masonry structures, as they are simplified models that can represent the interaction between different masonry components. Although much progress has been recently made on the compressive behavior of masonry prisms, review papers on this topic were published many years ago. Then, this paper aimed to investigate the current state-of-the-art on this topic. The following contributions derived from this review: identification and comparison of the compressive behavior of prisms constructed with innovative materials created in recent years; detection of topics for improvement of masonry design codes, associated with the mutual dependency of many factors affecting the mechanical performance of prisms; discussions of prism case scenarios often neglected in past literature; compilation of advances in model predictions of prisms’ compressive behavior; emerging technologies for assessment of safety of masonry elements is discussed based on minor-destructive tests (MDT) and non-destructive tests (NDT) for strain monitoring and damage detection in masonry prisms. Future development trends for studies on this topic were also presented.
... The results showed that the incorporation of multi-walled carbon nanotubes could improve the strength of concrete both prior to and after exposure to fire. C. Maraveas [21,22] conducted a sensitivity study on the performance of 19th century fireproof flooring systems at high temperatures, and the applicability of the Eurocode expressions to 19th century fireproof flooring systems is satisfactory. Incorporating appropriate amounts of polypropylene (PP) fibers into concrete not only improves the material properties but also enhances its fire resistance and prevents high-temperature bursting [23]. ...
Scoria aggregate concrete (SAC) as new green material has been gradually used in some construction projects for its lightweight and high strength, which can reduce the environmental impact of construction materials. In this paper, the residual mechanical properties and intact compressive stress–strain relationships of polypropylene (PP) fiber-reinforced Scoria aggregate concrete after high-temperature exposure at 20, 200, 400, 600, and 800 °C were investigated. The failure modes of PP fiber-reinforced Scoria aggregate concrete specimens and the effect of high temperatures on the peak stress, secant modulus, and peak strain were obtained. The results showed that the residual compressive strength of heated concrete is significantly reduced when the temperature exceeds 400 °C. The residual strength and residual secant modulus of PP fiber-reinforced Scoria aggregate concrete are significantly higher than those of ordinary concrete. The Scoria aggregate concrete specimens with PP fibers exhibited fewer surface cracks and fewer edge bursts under high temperatures. The residual stress–strain equation of the Scoria aggregate concrete was established by regression analysis, which agreed well with the experimental results.
... They can be calculated by the expression related to temperature T. Referring to previous studies [38][39][40][41], Table 1 lists the thermal parameters of concrete meso components at normal temperature. For heat conductivity of mortar matrix at different temperatures, the recommended formula in Eurocode [42] verified by Maraveas et al. [43] was applied and its expression can be given as: ...
The investigations on the influence of geometric dimension on concrete failure at normal temperature have made a fruitful progress, while the investigations on the size effect of concrete at elevated temperature approach blank. For investigating the influence of elevated temperature and dimension on static and dynamic failures of concrete, a 3D thermo-mechanical coupling method considering the meso-structural characteristics of concrete and the strain rate effect of material was established. Flexural-tensile failure analyses of concrete beams with different geometric dimensions were conducted after heat conduction analysis. The results reveal that the speed of the heat transfer is relatively fast in small-sized concrete and the heat conduction behavior quickly approaches an equilibrium state. There is a significant degradation behavior on dynamic flexural-tensile strength for concrete exposed to fire. The elevated temperature can weaken the strain rate hardening-effect of concrete. At normal temperature, the influence of geometric dimension on dynamic flexural-tensile strength can be weakened at low strain rates while there is a reverse size effect at high strain rates. At elevated temperature, with the increasing geometric dimension, the flexural-tensile strength first decreases and then increases at low strain rates while the strength increases steadily as subjected to high strain rates.
... The use of slim floor systems for the construction of high-rise buildings, car parks and offshore structures has increased significantly during the last two decades [1]. Although slim floor construction has gained vast popularity in the recent times, Jack arch type of slim floors were first used in the 1790s [4] [5]. During the 19th century, filler joist type of slim floor construction was often used [6]. ...
Slim floor systems possess favourable thermal and thermo-mechanical behaviour in comparison with the traditional steel-concrete composite beams. Despite a recent surge in their usage in the construction sector, there is limited research on their performance at elevated temperatures. Due to limited investigations, there is a lack of fire design guidance for slim floor beams in major structural design codes. This study addresses the response of slim floor systems at elevated temperatures through experimental and analytical investigations. The experimental work consists of fire tests to study the thermo-mechanical response of SFBs in standard fire conditions. In addition to their thermo-mechanical response in fire, the efficiency of the rebars as an aid to enhance their fire resistance being an alternative to fire protection materials is also investigated. The test results show that the fire resistance of slim floor beams is significantly higher than the traditional steel-concrete composite beams due to the thermal gradient resulting from the concrete encasement. Further, the presence of longitudinal steel rebars enhances the fire resistance of SFBs significantly as they add to the flexural resistance of SFBs. During the tests, additional fire resistance of 79 minutes was achieved by the aid of steel rebars, a useful alternative to the fire protection materials which have been found to be toxic to the environment. Keeping in view the useful contribution of the steel rebars, a sensitive study was conducted using the finite element modelling to analyse the influence of their size and positioning on the fire resistance of the slim floor beams. Finite element modelling was later used to conduct a parametric study to analyse the influence of the degree of utilization on the response of slim floor beams exposed to standard fire. Degree of utilization represents the ratio between the applied load during a fire limit state and the capacity of the structural member at the ambient temperatures. The results from the parametric study were used to develop a simple design methodology by relating the degree of utilization and the average critical temperatures. Due to lack of fire design guidance in Eurocode 4, engineers usually use the design guidance proposed in Eurocode 3 which produces conservative results if applied to perform the fire design of slim floor beams as they have been developed for steel and traditional composite beams. The proposed methodology during this study is similar to that available in the Eurocodes for steel and composite beams but is developed specifically for the fire design of slim floor beams.
... Maraveas et al. [28,29] demonstrated that there are correlations between the Eurocode mathematical expressions and lightweight concrete properties. They can be used to assess the impact of thermal properties, dependent on temperature, on the mechanical properties of lightweight concrete. ...
Chimneys are structures designed to convey exhaust gases from heating devices to the outside of buildings. The materials from which they are made have a great impact on their fire safety, as well as on the safety of the whole building. As current trends in the construction industry are moving towards improving the environmental impact and fire safety, changes to building materials are constantly being introduced. This also applies to the development of chimney technology, as there is still a recognised need for new solutions when it comes to materials used in the production of chimney systems. This article presents the findings of tests carried out on a chimney made from innovative perlite concrete blocks. Four different perlite concrete blocks that differed in bulk densities were analysed. The obtained results were then compared with widely used leca (lightweight expanded clay aggregate) concrete blocks. The test results confirmed high insulation properties of the perlite concrete block, from which the innovative chimney casing was made. The fire safety level was maintained even in high temperatures that occur during soot fire (1000 °C). These properties were retained despite there being no additional insulation of the flue duct. Even though the thermal load decreased the compressive strength of the chimney blocks, they still displayed sufficient average strength of 4.03 MPa. Additionally, the test results confirmed the possibility of recovering heat from the chimney with the efficiency of 23–30%, which constitutes a considerable increase compared to chimneys made from leca concrete blocks.
... According to current knowledge, the above-mentioned division of ceiling structures, from the point of view of fire resistance, is overly simplified and inaccurate [11,12]. Nevertheless, at the time of formulating the above-cited building regulations, it was a significant step to increase the safety of buildings, i.e., also city apartment buildings. ...
An urban residential building from the second half of the 19th century and the start of the 20th century, the so-called tenement house, is a significant representative of the architecture of the developing urban fabric in Central Europe. The vertical and horizontal load-bearing structures of these houses currently tend to show characteristic, repeated defects and failures. Their knowledge may, in many cases, facilitate and speed up the design of the historic building’s restoration without compromising its heritage value in this process. The article presents the summary of the most frequently occurring defects and failures of these buildings. The summary, however, is not an absolute one, and, in the case of major damage to the building, it still applies that, first of all, a detailed analysis of the causes and consequences of defects and failures must be made as a basic prerequisite for the reliability and long-term durability of the building’s restoration and rehabilitation. An integral part of the rehabilitation of buildings must be the elimination of the causes of the appearance of their failures and remediation of all defects impairing their structural safety, health safety and energy efficiency.
... During the last quarter of the 20 th century, the use of slim floor systems gained popularity in the Nordic countries as they offer numerous advantages over the traditional steel-concrete composite beams [1]. Although the slim floor technology has recently gained admiration, the art of shallow floor construction is being used since the 1790s as the filler joist type of shallow floor systems were frequently used [2]. The slim floor technology was introduced in the United Kingdom (UK) during the 1990s [3]. ...
... Slim floor beams became prominent in the Nordic countries during late 1970s as they offer numerous advantages over traditional composite beams with hanging steel sections [1]. Though the slim floor technology has recently got a wider acceptance, the art of shallow floor construction is being used since the 1790s [2]. Earlier, during the 19 th century, filler joist type of shallow floor systems were frequently used [2]. ...
... Though the slim floor technology has recently got a wider acceptance, the art of shallow floor construction is being used since the 1790s [2]. Earlier, during the 19 th century, filler joist type of shallow floor systems were frequently used [2]. The shallow floor construction was however forgotten and not much attention was paid till the 1970s when Hat beams and Thor beams were introduced in the Nordic countries. ...
... (2) Where, L is the clear span of the specimen: d is the depth of the beam, the distance from top to the bottom. Failure criteria in Eq. (2) are only applicable when the deflection has exceeded L/30. ...
Fabricated slim floor beams are produced by welding a steel plate to the bottom flange of an I-shaped steel section. The welded steel plate makes them structurally efficient and serves as a platform to support the steel decking of composite floor and the pre-cast concrete slabs. During their fabrication, an air-gap is induced between the steel plate and the bottom flange. Previous experimental investigations have shown that this air-gap has an influence on their thermal behaviour at elevated temperatures. Though the air-gap presence has an influence on their thermal performance, no investigations have yet been conducted to analyse its effects on their structural response in fire. This research investigates the effects of air-gap on structural response of fabricated slim floor beams in fire. During this study, finite element modelling is performed to simulate the response of fabricated slim floor beams and the predicted behaviour is verified against the available test data from literature. The validated finite element model is then employed to perform parametric studies to investigate the effects of the presence and size of the air-gap on their response in fire. Results obtained show that the presence of the air-gap has a significant influence on structural response of these beams at elevated temperatures. On the other hand, the size of air-gap has no or negligible effect on their thermal behaviour as well as on their structural response in fire. It was found that the presence of the air-gap restricts temperatures on the bottom flange and helps in achieving an improved fire resistance. As the presence of the air-gap is found to be helpful and beneficial, findings from this research can be used to develop similar designs for structural members as an efficient and inexpensive way to improve their behaviour in fire.
... Shallow floor systems gained popularity in Scandinavian countries during the last quarter of the twentieth century as they offered numerous advantages over traditional composite beams with down-stand steel sections (Lu and Mäkeläinen, 1996). Though the art of shallow floor construction has only gained popularity recently, these floors however, have been in use since the 1790s (Maraveas et al., 2013;Maraveas et al., 2014). During the nineteenth century, filler joist type of shallow floor construction was frequently used where the cast iron or wrought iron sections were encased in early concrete or masonry (Maraveas et al., 2013). ...
... Though the art of shallow floor construction has only gained popularity recently, these floors however, have been in use since the 1790s (Maraveas et al., 2013;Maraveas et al., 2014). During the nineteenth century, filler joist type of shallow floor construction was frequently used where the cast iron or wrought iron sections were encased in early concrete or masonry (Maraveas et al., 2013). Shallow floor construction was then forgotten and not much attention was paid until the 1970s when Hat beams and Thor beams were introduced in Sweden and its neighbouring countries. ...
Purpose – The purpose of this study is to investigate the effect of the airgap on thermal behaviour and structural response of fabricated slim floor beams (FSFBs) in fire.
Design/methodology/approach – A detailed analytical model is established and validated by replicating the response of FSFBs. The validated finite element modelling method is then used to perform sensitivity analysis. First, the influence of the airgap presence is analysed, and later, the effect of the airgap size on thermal behaviour and structural response of FSFBs at elevated temperatures is investigated.
Findings – Results from the study demonstrate that the presence of the airgap has a considerable influence on their thermal behaviour and structural response of FSFBs. The size of the airgap, however, has no significant influence on their thermal and structural response in fire.
Originality/value – No investigations, experimental or analytical, are available in literature addressing the effect of airgap on the structural response of FSFBs in fire. The presence of airgap is helpful and beneficial; hence, the findings of this research can be used to develop designs for structural members with airgap as an efficient and inexpensive way to improve their response in fire.
