Fire Behaviour

Fire induced geometrical changes produce large deflections in floor slabs and even if there is significant loss of strength, the change of shape of the slab allows stability to be maintained by the slab acting as a tensile membrane. This of course depends upon the amount and arrangement of reinforcement and the end restraint conditions of the slab. If the slab is continuous over the supports and the continuity of reinforcement over the support can also be assumed then the "anchoring" of the tensile membrane action is not in doubt. There is however a mechanism by which even simply supported slabs can produce a degree of tensile membrane action. In this case although there are no lateral (or in-plane) reactions available at the supports, there is a self-equilibrating mechanism that occurs in the form of a "compressive ring" between the central and perimeter regions of the slab which provides restraint to the membrane tensions (rather like the rigid ring surrounding a trampoline). Some authors have used this to develop design methods for non-continuous simply supported slabs in fire; however there is a great deficit of knowledge regarding the quantification of this effect. One of the key parameters that may govern the magnitude of "membrane enhancement" available for simply supported slabs is the ratio of slab thickness to its "overlap length" from the edge of the support. This paper will present initial conclusions obtained from this study and discuss the implications for design.

Cast-iron girders were used in many nineteenth century structures, especially in fireproof flooring systems (such as jack arches). Many such structures are still in use today and it is important that they fulfil the current requirements on fire resistance when there is a change of use. Cast iron has limited ductility so it is not possible for cast-iron beams to achieve total plasticity as for modern steel beams. Furthermore, cast iron has different mechanical properties in tension and compression and there is often a severe non-uniform temperature distribution in cast-iron beam sections. This paper presents the development of a simplified method to calculate the bending moment capacity of cast-iron beams in a jack arched system exposed to a standard ISO 834 fire. The method is based on an assumed strain distribution in the cross-section. A comparison of the results calculated using the simplified method with those using the fibre method, validated by Abaqus simulation results, indicates that the proposed simplified method is sufficiently accurate as the basis of a design method. 1 Structures and Buildings Moment capacity of cast-iron beams exposed to fire Maraveas, Wang and Swailes Proceedings of the Institution of Civil Engineers

Two types of fireproof flooring systems commonly encountered in the 19 th century are the "jack arch floor" and "the filler joist floor". A proper evaluation of their fire resistance requires reliable information of the thermal and mechanical properties of their construction materials, namely cast iron, wrought iron, mild steel, "early" concrete and masonry, at elevated temperatures. This paper collates temperature-dependent thermal (i.e. thermal conductivity and specific heat) and mechanical properties (i.e. yield strength, tensile or compressive strength, Young's elastic modulus and thermal expansion) of the metals as well as the temperature dependent thermal properties of the "insulation" from literature. The collated data are then compared with Eurocode's mathematical expressions for contemporary materials to assess the applicability of the Eurocode expressions for the 19 th century fireproof flooring systems.

Cast iron beams were extensively used in many 19th century structures, especially in fireproof flooring systems (such as jack arch). Many such structures are still in use today and it is important that they fulfil the current requirements of fire resistance when there is a change of use. These structures are out of scope of modern design codes and old design codes do not provide guidance for fire resistance design. Furthermore, cast iron is a brittle material weak in tension, and there are many uncertainties in its mechanical properties at ambient and elevated temperatures due to material flaws. It is necessary to quantify the probability of structural failure and to introduce safety factors to reduce the probability of structural failure in fire to an acceptable level. This paper presents the results of a detailed study whose purpose is to derive appropriate safety factors to achieve different levels of reliability, for fire safety design of cast iron beams. In this study, a fibre analysis method has been used to calculate the moment capacity of four different types of cast iron cross section. Using randomized stressstrain-temperature relationships, based on variability of the different governing parameters (under tension: maximum stress, 0.2% proof stress, corresponding strains at maximum stress (strength) and failure; under compression: Young's modulus, proportional limit, 0.2% proof stress and the maximum stress), the probability distribution of moment capacity has been calculated. Based on the criterion of cast iron beam failure not exceeding probabilities of 10 -1 , 10 -2 and 10 -3 , material safety factors of 1.5, 3.0 and 5.0 respectively have been obtained.

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.

This paper presents the fire resistance behaviour of the Ultra Shallow Floor Beams (USFB) partially encased in concrete using numerical analysis method based on material specifications of the EN1994-1-2. Investigating the behavior of USFBs under elevated temperatures is crucial in determining their fire resistance and evaluating their overall performance in contemporary construction. Even though the manufacturing company provides fire resistances for USFBs based on EC4-1-2 procedures, their response to elevated temperature effects remains up to date neither well documented nor clearly understood. The analyses involved two different beams of span 5m and 8m respectively, as specified by the manufacturer. Analysis results showed that such beams, when unprotected, experience severe temperature gradients if exposed to fire, as the lower flange still remains unprotected in contrast to the concrete encased part of the crosssection. As it was anticipated, the moment capacity governs the fire resistance of the beams and the load factor highly effects the elevated temperature behavior. In addition, the loss of the lower flange, which develops high temperatures, is not compensated by the web and consequently the moment capacity ultimately depends on the temperature of the lower flange. Results also suggest that simulated beams sustained the applied load for approximately 40min of exposure to the standard fire.

Purpose This paper aims to present technical aspects of the assessment method and evaluation of fire damaged steel structures. The current work focuses on the behavior of structural normal steel (hot-rolled and cold-formed) and high-strength bolts after exposure to elevated temperatures. Information on stainless steel, cast iron and wrought iron is also presented. Design/methodology/approach Because of the complexity of the issue, an elaborate presentation of the mechanical properties influencing factors is followed. Subsequently, a wide range of experimental studies is extensively reviewed in the literature while simplified equations for determining the post-fire mechanical properties are proposed, following appropriate categorization. Moreover, the reinstatement survey is also comprehensively described. Findings Useful conclusions are drawn for the safe reuse of the structural elements and connection components. According to the parametric investigation of the aforementioned data,...

Se revisan los incendios forestales ocurridos en California en enero-febrero 2025 y en particular el estudio publicado por la World Weather
Attribution que indica que el calentamiento global incrementó la
destructividad de los incendios forestales ocurridos en Los
Ángeles a principios de 2025.

Cover Image: Fires set by chagras (Andean cowboys) to renew forage grasses are favoring páramo grasslands in Ecuador at the expense of Polylepis species that dominate Andean dwarf forests. © Pete Oxford/Minden Pictures Top Back Cover: The Brazilian Cerrado, once covering 22 percent of the country or 2 million sq. km, is a mosaic of savanna and shrubland molded by a diversity of fire regimes. © Tui De Roy/Minden Pictures Middle Back Cover: Traditional agriculture (tavy) in Madagascar.

Cover Image: Fires set by chagras (Andean cowboys) to renew forage grasses are favoring páramo grasslands in Ecuador at the expense of Polylepis species that dominate Andean dwarf forests. © Pete Oxford/Minden Pictures Top Back Cover: The Brazilian Cerrado, once covering 22 percent of the country or 2 million sq. km, is a mosaic of savanna and shrubland molded by a diversity of fire regimes. © Tui De Roy/Minden Pictures Middle Back Cover: Traditional agriculture (tavy) in Madagascar.

Background: Thinking styles lead to describe how people use their abili es when they have to deal with problem solving situa ons. The Thinking Styles Inventory –TSIis one of the most worldwide employed scales, developed to assess 13 thinking styles posed in the Theory of Mental Selfgovernment -Legisla ve, Execu ve, Judicial, Monarchic, Hierarchic, Oligarchic, Anarchic, Global, Local, Internal, External, Liberal, Conserva ve. Method: Aiming at the adapta on of the scale to local college students' popula on, linguis c aspects were reviewed as well as the response scale. A er a pilot study, a sample composed of 361 college students from Buenos Aires responded the inventory in order to perform exploratory and confirmatory factorial analyzes on the one hand, and an internal consistency on the other. Result: A 7-factor structure -Judicial/Liberal, Execuve/Conserva ve, External, Monarchic, Global, Hierarchic, Legisla ve-, was obtained. Conclusion: Such a version maintained 45 of the 10...

The increasing demand for lightweight, corrosion-resistant fuel storage solutions has increased the interest in composite pressure vessels;  however,  their industrial adoption remains limited due to the lack of standardized design frameworks under international codes. This study presents a structured approach for designing and validating an ASME Section-X,  compliant composite fuel storage tank using E-glass fibers and vinyl ester resin.  The research addresses the absence of scalable methodologies by integrating analytical modeling, hybrid manufacturing strategies,  and finite element analysis  (FEA)  for structural validation. A vertical fuel storage tank was developed with detailed calculations, and design requirements are achieved according to  Class  II  structural requirements under the  ASME  Section  X  safety factor guidelines (2.5× burst pressure).

Canaima National Park (CNP, Venezuela), located in the core of Guiana Shield and inhabited by the Pemón indigenous people, is an area of great value due to its biological and cultural singularity. High incidence of fires, together with increased forest vulnerability to fire as a result of global climate and socio-environmental changes, have been considered threats, since they could put at risk, both ecosystems and human well-being. The conflict over fire use is exacerbated by the fact that whereas the Pemón depend for their livelihood on the use of fire, the policy of CNP government agencies has been fire exclusion (although this is not effectively enforced). The aim of this work is to present the experience gained during the development, for almost 20 years, of three participative and trans-disciplinary research-action areas: 1) long-term indigenous, fire-fighters and scientists collaborative fire experiments to study fire behavior and effects on bio-geo-chemical cycles and biodive...

Effect of turbulence on wildfire propagation 1 STEFANO LEONARDI, MARTAND MAYUKH GARIMELLA, UMBERTO CIRI, The University of Texas at Dallas -Wildfires are natural hazards which pose existential threat to humanity and nature. To ensure minimal damage, predictive monitoring systems have been established and are being improved by research. In recent times, numerical fire prediction models have been developed by coupling numerical weather prediction (NWP) models with fire propagation models. However, to minimize computational time, the NWPs are run at a coarser resolution relative to the resolution of the fire models. This gap in resolution is counterproductive as details of small scale interactions, which can lead to extreme events such as crown fires, are neglected. To investigate this effect, large eddy simulations (LES) are performed to propagate a two dimensional fire front using the level-set method which is advanced in time by a third-order Runge-Kutta algorithm. The heat flux generated from the fire is fed back to LES as boundary condition and the effect of buoyancy on wind propagation is included to model a realistic fire weather interaction. From the simulation data, the effects of small scale turbulence structures and change in local atmospheric conditions on fire spread are analyzed. The LES simulation results are compared with the weather research and forecast (WRF) model simulation for wildland fire.