Journal articles on the topic 'Fire Loading'
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1
Skowronski, Nicholas S., Michael R. Gallagher, and Timothy A. Warner. "Decomposing the Interactions between Fire Severity and Canopy Fuel Structure Using Multi-Temporal, Active, and Passive Remote Sensing Approaches." Fire 3, no. 1 (March 10, 2020): 7. http://dx.doi.org/10.3390/fire3010007.
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Within the realms of both wildland and prescribed fire, an understanding of how fire severity and forest structure interact is critical for improving fuels treatment effectiveness, quantifying the ramifications of wildfires, and improving fire behavior modeling. We integrated high resolution estimates of fire severity with multi-temporal airborne laser scanning data to examine the role that various fuel loading, canopy shape, and other variables had on predicting fire severity for a complex of prescribed fires and one wildfire and how three-dimensional fuels changed as a result of these fires. Fuel loading characteristics were widely variable, and fires were ignited using a several techniques (heading, flanking, and backing), leading to a large amount of variability in fire behavior and subsequent fire effects. Through our analysis, we found that fire severity was linked explicitly to pre-fire fuel loading and structure, particularly in the three-dimensional distribution of fuels. Fire severity was also correlated with post-fire fuel loading, forest structural heterogeneity, and shifted the diversity and abundance of canopy classes within the landscape. This work demonstrates that the vertical distribution of fuel is an important factor and that subtle difference has defined effects on fire behavior and severity.
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Lutes, Duncan C., Robert E. Keane, and John F. Caratti. "A surface fuel classification for estimating fire effects." International Journal of Wildland Fire 18, no. 7 (2009): 802. http://dx.doi.org/10.1071/wf08062.
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We present a classification of duff, litter, fine woody debris, and logs that can be used to stratify a project area into sites with fuel loading that yield significantly different emissions and maximum soil surface temperature. Total particulate matter smaller than 2.5 μm in diameter and maximum soil surface temperature were simulated using the First Order Fire Effects Model. Simulation results were clustered into 10 Effects Groups using an agglomerative routine where each Effects Group defined a unique range of soil temperature and emissions. Classification tree analysis was used to estimate the critical duff, litter, fine woody debris, and log loadings associated with the soil temperature and emissions of each Effects Group. The resulting 21 fuel classes are called Fuel Loading Models and classified the study dataset with an ~34% misclassification rate. The classification can be used to describe fuel loadings for a plot or stand, or as map units for mapping fuel loadings across large regions. The classification process can be used to develop finer-scale fuel classifications for specific regions or ecosystems.
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Saura-Mas, S., S. Paula, J. G. Pausas, and F. Lloret. "Fuel loading and flammability in the Mediterranean Basin woody species with different post-fire regenerative strategies." International Journal of Wildland Fire 19, no. 6 (2010): 783. http://dx.doi.org/10.1071/wf09066.
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The flammability and combustibility of plant communities are determined by species features related to growth-form, structure and physiology. In some ecosystems, such as the Mediterranean ones, these characteristics may contribute to the existence of fire-prone species. We measured several parameters associated with the flammability and fuel loading of dominant woody species with different post-fire regenerative strategies (seeders and non-seeders) in shrublands in the western Mediterranean Basin. Overall, seeder species show lower fuel load but are more prone to burning owing to a higher dead-to-live fuel ratio, live fine-fuel proportion and dead fine-fuel proportion. Moreover, they burst into flame at lower temperatures than non-seeders. In the Mediterranean Basin, most seeder species emerged mainly during the Quaternary, under a highly fluctuating Mediterranean climate and during recurrent fires. We propose that properties related to the combustibility and flammability of seeders may be the result of selective pressures associated with both fire and climate. These results suggest that ecosystems dominated by seeder species are more susceptible to fire risk than those dominated by non-seeder species in the Mediterranean Basin. Therefore, the proportion of these types of species resulting from previous fire or management history is likely to determine the characteristics of future fire events.
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Lemmerer, Johann, Wolfgang Kusterle, Wolfgang Lindlbauer, Matthias Zeiml, Rudolf Hörhan, and Johannes Steigenberger. "Fire Loading of Highly Fire-Resistant Concrete Tunnel Linings." IABSE Symposium Report 90, no. 7 (January 1, 2005): 31–38. http://dx.doi.org/10.2749/222137805796270919.
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Zhao, Fengjun, Yongqiang Liu, Scott Goodrick, Benjamin Hornsby, and Jeffrey Schardt. "The contribution of duff consumption to fire emissions and air pollution of the Rough Ridge Fire." International Journal of Wildland Fire 28, no. 12 (2019): 993. http://dx.doi.org/10.1071/wf18205.
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It is typically difficult to burn duff because of high fuel moisture; however, under persistent drought conditions, duff will burn readily. This study investigates the burning of a deep duff layer by the 2016 Rough Ridge Fire, in the southern United States, under drought conditions and evaluates the contribution of duff consumption to fire emissions and air pollution. Fuel loading was measured and used to evaluate the BlueSky framework. Smoke was simulated for three fuel loading and moisture scenarios of field measurement, BlueSky estimated fuel loading, and a hypothetical moist condition. The measured fuels had a very deep duff layer that had accumulated over decades due to the lack of historical fires, most of which was burned by the fire. The burning of this deep duff layer contributed substantially to the increased fire emissions at the fire site and the air pollution in metro Atlanta. In contrast, BlueSky under-predicted duff loading and fire emissions. As a result, no major air pollution episodes were predicted for metro Atlanta. The high-moisture scenario also failed to produce a major air-pollution episode within Atlanta, which highlights the contribution of the drought to the air-pollution episode within Atlanta.
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Skibicki Ł, Dariusz, Łukasz Pejkowski, and Michał Stopel. "Finite Element Analysis of Ventilation System Fire Damper Dynamic Time-History." Polish Maritime Research 24, no. 4 (December 20, 2017): 116–23. http://dx.doi.org/10.1515/pomr-2017-0143.
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Abstract The paper presents results of the numerical analysis of the fire damper used in ventilation systems under the earthquake loading. The research was conducted in accordance with the recommendations of the Nuclear Safety Standards Commission. The aim of the analysis was to examine the fire damper with respect to its resistance to service loadings, structural integrity, and capability to stay operative after an earthquake. The analysis was carried out using the Finite Element Method in LS-Dyna software. The earthquake loading was modelled as accelerations, measured in three directions during the earthquake. For modelling of the materials behaviour, material models taking into account the influence of strain rate on hardening were used. The analysis consisted of three stages, which were: loading the construction with the earth gravity, earthquake simulation by loading with accelerations in three directions, and, finally, closing the fire damper. The analysis has shown that some of the construction elements undergo plastic deformations. However, the performed simulation of fire damper closing showed that despite these deformations, the device remains capable to keep its functionality and the damper closes hermetically. The results of the analysis were important design indications for the fire damper prototype.
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Balázs, György L., and Olivér Czoboly. "Fibre Cocktail to Improve Fire Resistance." Key Engineering Materials 711 (September 2016): 480–87. http://dx.doi.org/10.4028/www.scientific.net/kem.711.480.
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Favourable experience with fibre reinforced concrete (FRC) resulted in its increasing use worldwide. The properties of fibre reinforced concrete are mostly influenced by the type and the amount of fibres. Our experimental study was directed to the possible improvements of the residual flexural strength and the properties of concrete exposed to high temperatures with different fibre cocktails including steel, micro polymer or cellulose fibres. The influence of type and amount of fibres on residual flexural strength in cold state were tested after 300, 500 or 800 °C temperature loading.
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Kukavskaya, Elena A., Galina A. Ivanova, Susan G. Conard, Douglas J. McRae, and Valery A. Ivanov. "Biomass dynamics of central Siberian Scots pine forests following surface fires of varying severity." International Journal of Wildland Fire 23, no. 6 (2014): 872. http://dx.doi.org/10.1071/wf13043.
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In 2000–2002 nine 4-ha prescribed fires of various severities were conducted on experimental plots in mature Scots pine forest in the central Siberian taiga, Russia. Total above-ground living biomass decreased after low- and moderate-severity fires by 10 and 15%, whereas high-severity fire reduced living above-ground biomass by 83%. We monitored changes in fuel structure and biomass for 6–8 years following these fires. By 6–8 years after burning the ground fuel loading had recovered to 101, 96 and 82% of pre-fire levels after fires of low-, moderate- and high-severity. Down woody fuel loading increased by 0.18±0.04kgm–2year–1. We developed regressions relating time since fire to changes in above-ground biomass components for fires of different severity for feather moss–lichen Scots pine forest of Siberia. Our results demonstrate the importance of both burn severity and composition of pre-fire surface vegetation in determining rates and patterns of post-fire vegetation recovery on dry Scots pine sites in central Siberia.
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Perryman, Holly A., Christopher J. Dugaw, J. Morgan Varner, and Diane L. Johnson. "A cellular automata model to link surface fires to firebrand lift-off and dispersal." International Journal of Wildland Fire 22, no. 4 (2013): 428. http://dx.doi.org/10.1071/wf11045.
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In spite of considerable effort to predict wildland fire behaviour, the effects of firebrand lift-off, the ignition of resulting spot fires and their effects on fire spread, remain poorly understood. We developed a cellular automata model integrating key mathematical models governing current fire spread models with a recently developed model that estimates firebrand landing patterns. Using our model we simulated a wildfire in an idealised Pinus ponderosa ecosystem. Varying values of wind speed, surface fuel loading, surface fuel moisture content and canopy base height, we investigated two scenarios: (i) the probability of a spot fire igniting beyond fuelbreaks of various widths and (ii) how spot fires directly affect the overall surface fire’s rate of spread. Results were averages across 2500 stochastic simulations. In both scenarios, canopy base height and surface fuel loading had a greater influence than wind speed and surface fuel moisture content. The expected rate of spread with spot fires occurring approached a constant value over time, which ranged between 6 and 931% higher than the predicted surface fire rate of spread. Incorporation of the role of spot fires in wildland fire spread should be an important thrust of future decision-support technologies.
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Zhang, Qian, Wen-yu Wang, Song-song Bai, and Ying-hua Tan. "Response analysis of tunnel lining structure under impact and fire loading." Advances in Mechanical Engineering 11, no. 3 (March 2019): 168781401983447. http://dx.doi.org/10.1177/1687814019834473.
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Accidents and fires in tunnels hinder traffic and threaten the safety of personal and material resources, moreover, impact and temperature effects often cause damage to structures, affect structural performance, and shorten the service life of structures. In this article, the response behavior of the tunnel lining under the action of vehicle impact and fire load is simulated and analyzed. As the failure criterion of the lining dome settlement and the sidewall convergence displacement, the system compares the two interaction effect of the load, namely, the influence of the fire load on the impact resistance of the lining and the influence of the impact load on its fire resistance. The results show that the fire load reduces the impact resistance of the lining. Compared with the initial static load, the impact of temperature on the impact resistance is more significant; the impact load has an adverse effect on the fire resistance of the lining, when the tunnel lining is subject to explosion first. After the impact load working on the fire, the fire resistance of the lining will be significantly reduced with the increase of the static load ratio and the dynamic load ratio. The research can provide the reference for the design of fire protection and explosion protection parameters of tunnel support structures.
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Kahanji, C., F. Ali, and A. Nadjai. "Explosive spalling of ultra-high performance fibre reinforced concrete beams under fire." Journal of Structural Fire Engineering 7, no. 4 (December 12, 2016): 328–48. http://dx.doi.org/10.1108/jsfe-12-2016-023.
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Purpose The purpose of the study was to investigate the spalling phenomenon in ultra-high performance fibre reinforced concrete (UHPFRC) beams on exposure to a standard fire curve (ISO 834) under a sustained load. Design/methodology/approach The variables in this study were steel fibre dosage, polypropylene (PP) fibres and loading levels. The research investigated seven beams – three of which contained steel fibres with 2 vol.%, another three had steel fibres with 4 vol.% dosage and the seventh beam had a combination of steel fibres (2 vol.%) and PP fibres (4 kg/m3). The beams were tested for 1 h under three loading levels (20, 40 and 60 per cent) based on the ambient temperature ultimate flexural strength of the beam. Findings Spalling was affected by the loading levels; it exacerbated under the load level of 40 per cent, whereas under the 60 per cent load level, significantly less spalling was recorded. Under similar loading conditions, the beams containing steel fibres with a dosage of 4 vol.% spalled less than the beams with fibre contents of 2 vol.%. This was attributed to the additional tensile strength provided by the excess steel fibres. The presence of PP fibres eliminated spalling completely. Originality/value There is insufficient research into the performance of UHPFRC beams at elevated temperature, as most studies have largely focussed on columns, slabs and smaller elements such as cubes and cylinders. This study provides invaluable information and insights of the influence of parameters such as steel fibre dosage, PP fibres, loading levels on the spalling behaviour and fire endurance of UHPFRC beams.
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Kwon, In Kyu, and Young Bong Kwon. "Evaluation of the Fire Resistance of H-Section Steel Columns and Beams." Applied Mechanics and Materials 204-208 (October 2012): 3190–93. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.3190.
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Building fires can cause severe damages to not only human life but also building structures. Therefore, every nation requires a building regulation related to fire in aspect of safety of human and structural stability. The structural stability under fire condition can be evaluated by the fire test defined in each nation’s standard. However, the results from the test don’t satisfy the real situations of the building such as fire loads, opening size, loading and boundary condition of structural members, and etc. Meanwhile, performance based fire engineering design is regarded as an alternative evaluation method of fire. The fire engineering method has been regarded as a more rational method than the prescriptive method in terms of accuracy and cost efficiency. Recently, the limit temperature method is regarded as the easiest fire engineering method to evaluate the structural stability under fire. To make the backbone of a specification of limiting temperature method, limiting temperatures of various structural members are required. In this paper, in order to make a database of the limiting temperatures of H-section columns and beams, fire test programs with loading were conducted and the limiting temperatures and fire resistance were derived.
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Asaro, Robert J., and Ming Dao. "Fire Degradation of Fiber Composites." Marine Technology and SNAME News 34, no. 03 (July 1, 1997): 197–210. http://dx.doi.org/10.5957/mt1.1997.34.3.197.
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This paper describes results from combined experimental and theoretical studies of compressive failures of polymer matrix glass reinforced composites which have undergone thermal loading. The materials discussed herein are composed of vinylester resins and E-glass, quasi-isotropic, fabrics with relatively high fiber densities in the 55 volume percent range. Both single skin and cored composite materials are addressed in our studies but the focus of the present paper is on single skin composites. Experimental studies have included structural collapse under combined thermal (i.e. fire) and mechanical loading; the mechanical loading included combined in-plane and out-of-plane loading of panels which were approximately 1 m2. Our theoretical studies include detailed finite element simulations of panel deformation and collapse to be compared with the experimental observations. The approach to the development of a quantitative methodology for structural fire protection is discussed in the context of the experiments and analyses. This approach is outlined using a simple analytical model for structural collapse; the model's predictions are compared with experiment and the numerical simulations.
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Ye, Hao-wen, Nai-qian Feng, Yan Ling-hu, Zhi-wei Ran, Li-xun Lin, Shi-kun Qi, and Yi Dong. "Research on Fire Resistance of Ultra-High-Performance Concrete." Advances in Materials Science and Engineering 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/530948.
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Fire resistance of ultrahigh-performance concrete was measured under different temperatures and loadings. C120 concrete was prepared with 1 kg/m3organic fiber and C120 concrete with 2 kg/m3organic fiber and tested under loading at 30% ultimate strength when exposed to high temperatures of 200°C, 300°C, and 400°C, respectively.
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Masoumi, Farshid, and Ebrahim Farajpourbonab. "Performance of parking steel column damaged by fire." Journal of Structural Fire Engineering 10, no. 2 (June 10, 2019): 138–54. http://dx.doi.org/10.1108/jsfe-03-2018-0006.
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Purpose The primary purpose of this research was to expand the knowledge base regarding the behavior of steel columns during exposure to fire. This paper presents the numerical study of the effect of heat on the performance of parking steel column in a seven-story steel building under cyclic loading. Design/methodology/approach In this research, the forces and deformations developed during a fire are estimated by using detailed 3D finite-element models. The analyses are in the form of a coupled thermo-mechanical analysis in two types of loading: concurrent loading (fire and cyclic loading) and non-concurrent loading (first fire and then cyclically), and the analyses have been conducted in both states of the fire loading with cooling and without cooling using the ABAQUS software. Further, it was investigated whether, during the fire loading, the specimen was protected by a 3-cm-thick concrete coating and how much it changes the seismic performance. After verification of the specimen with the experimental test results, the column model was investigated under different loading conditions. Findings The result of analyses indicates that the effect of thermal damage on the performance of steel columns, when cooling is happening late, is more than the state in which cooling occurs immediately after the fire. In this paper, thermal–seismic performance of parking steel columns has been specified and the effect of the fire damage has been investigated for the protected steel by concrete coating and to the non-protected steel, under both cooling and non-cooling states. Originality/value This study led to recommendations based on the findings and suggestions for additional work to support performance-based fire engineering. It is clear that predicting force and deformation on steel column during fire is complex and it is affected by many variables. Here in this paper, those variables are examined and proper results have been achieved.
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Chang, Chuan Peng, Shi Wu Huang, Xue Feng Li, Bo Tian, and Zi Yi Hou. "A Study of the Capability for Fire Resistance of Polypropylene Fibre Concrete." Advanced Materials Research 857 (December 2013): 116–23. http://dx.doi.org/10.4028/www.scientific.net/amr.857.116.
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The purpose of this paper is to examine the effect of various polypropylene fibre additions (length and content) to concrete on compressive strength and explosive spalling when subjected to high temperatures, which simulate the building or tunnel fires. The experimental results show that the compressive strength of polypropylene fiber concrete (PFC) and plain concrete decreases with increasing temperature. Fibre content in a certain range has a small effect on the compressive strength of the concrete, therefore the polypropylene (PP) fibers has a great influence on the anti-spalling behavior of concrete under fire loading to ensure the integrity of the structure. Keywords: concrete, polypropylene fibre, high temperature, compressive strength, spalling
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da Silva, Luis Simoes, Aldina Santiago, Paulo Vila Real, and David Moore. "Behaviour of steel joints under fire loading." Steel and Composite Structures 5, no. 6 (December 25, 2005): 485–513. http://dx.doi.org/10.12989/scs.2005.5.6.485.
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Radzi, Noor Azim Mohd, Roszilah Hamid, Azrul A. Mutalib, and A. B. M. Amrul Kaish. "A Review of the Structural Fire Performance Testing Methods for Beam-to-Column Connections." Advances in Civil Engineering 2021 (November 3, 2021): 1–18. http://dx.doi.org/10.1155/2021/5432746.
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The structural fire performance tests for beam-to-column connections are critical in determining their fire performance at high temperatures. The current standard fire testing methods provide the procedures for establishing the fire resistance of each construction element exposed to a standard fire. However, these methods cannot verify the fire behaviour of the connections between building elements. Researchers have performed numerous fire tests on beam-to-column connections despite the lack of structural fire performance testing methods. This paper presents a comprehensive literature review of the structural fire performance testing methods for beam-to-column connections. The major areas in this review are travelling fires, development of travelling fires on beam-to-column connections, fire testing considerations, fire testing criteria, recent fire testing, and loading applications. This paper identifies the key issues and challenges of the structural fire performance testing methods for beam-to-column connections. Finally, this paper provides recommendations and discusses the way forward for structural fire performance tests on beam-to-column connections.
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Call, PT, and FA Albini. "Aerial and Surface Fuel Consumption in Crown Fires." International Journal of Wildland Fire 7, no. 3 (1997): 259. http://dx.doi.org/10.1071/wf9970259.
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An empirical model is presented which relates fractional reduction in loading to fuel element diameter and moisture content for surface and aerial fuels consumed near the fire front in a spreading crown fire. The model is based upon data from a series of experimental crown fires in immature jack pine. Its intended use is to permit calculation of fuel consumption per unit area (kg/m2) needed to estimate edge intensity (kW/m) from the spread rate of a crown fire. Model predictions of small fuel component fractional loading reduction had a root-mean-square error of almost 0.2 for our calibration data set. Most of the error arises from the model prediction of complete consumption of crown foliage, some of which was not exposed to flame in the fires of our data set. The model does not address the longer term burning of duff and large woody fuels.
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Naser, Mohannad, and Venkatesh Kodur. "Response of fire exposed composite girders under dominant flexural and shear loading." Journal of Structural Fire Engineering 9, no. 2 (June 11, 2018): 108–25. http://dx.doi.org/10.1108/jsfe-01-2017-0022.
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Purpose This paper aims to present results from numerical studies on the response of fire exposed composite girders subjected to dominant flexural and shear loading. A finite element-based numerical model was developed to trace the thermal and structural response of composite girders subjected to simultaneous structural loading and fire exposure. This model accounts for various critical parameters including material and geometrical nonlinearities, property degradation at elevated temperatures, shear effects, composite interaction between concrete slab and steel girder, as well as temperature-induced local buckling. To generate test data for validation of the model, three composite girders, each comprising of hot-rolled (standard) steel girder underneath a concrete slab, were tested under simultaneous fire and gravity loading. Design/methodology/approach The validated model was then applied to investigate the effect of initial geometric imperfections, load level, thickness of slab and stiffness of shear stud on fire response of composite girders. Findings Results from experimental and numerical analysis indicate that the composite girder subjected to flexural loading experience failure through flexural yielding mode, while the girders under shear loading fail through in shear web buckling mode. Further, results from parametric studies clearly infer that shear limit state can govern the response of fire exposed composite girders under certain loading configuration and fire scenario. Originality/value This paper presents results from numerical studies on the response of fire exposed composite girders subjected to dominant flexural and shear loading.
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Davies, Kirk W., Chad S. Boyd, Jon D. Bates, and April Hulet. "Winter grazing can reduce wildfire size, intensity and behaviour in a shrub-grassland." International Journal of Wildland Fire 25, no. 2 (2016): 191. http://dx.doi.org/10.1071/wf15055.
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An increase in mega-fires and wildfires is a global issue that is expected to become worse with climate change. Fuel treatments are often recommended to moderate behaviour and decrease severity of wildfires; however, the extensive nature of rangelands limits the use of many treatments. Dormant-season grazing has been suggested as a rangeland fuel treatment, but its effects on fire characteristics are generally unknown. We investigated the influence of dormant-season (winter) grazing by cattle (Bos taurus) on fuel characteristics, fire behaviour and area burned in Wyoming big sagebrush (Artemisia tridentata subsp. wyomingensis) shrub-grassland communities in south-eastern Oregon, USA. Winter grazing was applied for 5 years before burning and compared with ungrazed areas. Winter grazing decreased fine fuels and increased fine fuel moisture, which reduced flame height and depth, rate of spread and area burned. Winter-grazed areas also had lower maximum temperature and heat loading during fires than ungrazed areas, and thereby decreased risk of fire-induced mortality of important herbaceous functional groups. These results suggest that winter grazing may be a fuel management treatment that can be applied across vast shrub-grasslands to decrease wildfire risk and fire intensity to mediate climate change effects on wildfire activity.
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Wang, Bin, Yu Li Dong, and Li Tang Gao. "Fire Experimental Study of Four-Edge Fixed Reinforced Concrete Slab in Fire." Advanced Materials Research 163-167 (December 2010): 1626–37. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1626.
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The performance of one full scale four- edge fixed reinforced concrete slab under the condition of combined effects of loading and fire was investigated. The specimens design, the test plan, the test contents and the test methods were firstly introduced. Through the experiments, the distribution of temperature field along the depth of the slab and the temperature changes of the inner steel were obtained, as well as the deformation of out-plane and in-plane and the rotation on the edges. The changing of reaction forces on the bearings of the slab with the temperature was also observed. The results indicated that, under the condition of fire, the out-plan deformation of the slab was much bigger than that of the normal temperature; non-linear temperature filed was existed along the depth of the slab; remarkable redistribution of the reaction forces were occurred on the fixed bearings. The fail pattern of the slab under the condition of combined effects of loading and fire was different from the static loading under normal temperature. The slab was suffered reverse forces because of the heat effects; hence the plastic hinge lines with the shape of elliptic basin were appeared on the top of the slab.
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Nguyen, Xuan Tung, and Jong Sup Park. "Inelastic Strength for Fire Resistance of Composite I-Beam Covered by Insulation Material Subjected to Basic Loading Condition." Metals 11, no. 5 (April 29, 2021): 739. http://dx.doi.org/10.3390/met11050739.
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This paper presents a nonlinear numerical study on the moment resistance of composite steel-concrete beam using fire insulation subjected to various fire scenarios and basic loading conditions. The temperature-dependent material properties of fire insulation, concrete and steel were taken into consideration. The nonlinear finite element analysis was done by utilizing a commercial finite element program, ABAQUS. The obtained moment capacity of the composite I-beam from the current fire code was also performed and compared. The results showed that the fire scenarios and the fire insulation thickness have a great influence on the temperature distribution and strength degradation of the composite beam. The capacity of the beam in hydrocarbon fires, which is the most severe scenario, decreases faster than that in ISO834 standard fire and external fire. The fire resistance of the beam increases as the fire insulation thickness increases due to the temperature degradation in the steel beam. The calculated results from the current fire codes give conservative value at normal temperature and low temperature. The current fire codes can give unconservative values at high temperature when there is a great temperature discrepancy between parts of the beam. A new factor was proposed to determine the fire moment resistance of the composite beam with non-uniform temperature.
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Suwondo, Riza, Martin Gillie, Lee Cunningham, and Colin Bailey. "Effect of earthquake damage on the behaviour of composite steel frames in fire." Advances in Structural Engineering 21, no. 16 (March 12, 2018): 2589–604. http://dx.doi.org/10.1177/1369433218761138.
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Fire loading following earthquake loading is possible in any building in a seismic-prone area. However, most design approaches do not consider fire following earthquake as a specific loading case. Moreover, seismic design philosophies allow a certain degree of damage in structural elements which make structures more vulnerable when subjected to post-earthquake fire. This study uses three-dimensional numerical models to investigate the effect of earthquake damage on the fire resistance of composite steel-frame office buildings. A total of two types of earthquake damage, fire insulation delamination and residual lateral frame deformation, are investigated. It is concluded that earthquake damage can significantly reduce the fire resistance of composite buildings, with delamination of fire protection having the greatest effect. The results of this study can be used by designers to improve the post-earthquake fire resistance of composite buildings.
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An, Jae Hong, In Hwan Yeo, Ki Soo Jeon, and Ki Ho In. "Study on Estimate of Load Ratio of Doubly Reinforced Concrete Beam Exposed to the Standard Fire." Key Engineering Materials 737 (June 2017): 465–70. http://dx.doi.org/10.4028/www.scientific.net/kem.737.465.
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There are a lot of concerns on safety structure performance by being buildings to be large and high-rise. In particular, damage due to the fire recently leads to a large disaster and therefore a variety of countries operate the regulation on the fire resistance performance depending on the building structure. There are differences on the fire resistance design in each country but 50% of the design load is suggested to be reasonable for the normal temperature during the fire by applying the concept of the loading ratio to the fire resistance design of structures. Since the loading ratio is the factor having a major impact on the evaluation of the fire resistance performance, it should be preferentially considered. The study on setting up the loading ratio to evaluate the fire resistance performance and safety of structures has yet to be fully furnished in South Korea. Therefore, in this paper, the loading ratio proper for the construction status in South Korea is to be taken into account and then the ratio is to be proposed on the single reinforcement beam.
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Engle, DM, and JF Stritzke. "Fire Behavior and Fire Effects on Eastern Redcedar in Hardwood Leaf-Litter Fires." International Journal of Wildland Fire 5, no. 3 (1995): 135. http://dx.doi.org/10.1071/wf9950135.
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Treatment of stands of hardwoods in the cross timbers of the central United States with tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-dimethylurea) can significantly decrease canopy cover of hardwoods. However, at the rate used for hardwood control, tebuthiuron does not control eastern redcedar (Juniperus virginiana L.). Our objective was to determine the potential of using fires in the hardwood leaf litter, either before or after tebuthiuron, for controlling eastern redcedar. To do this, we compared fuelbed characteristics, fire behavior, and fire effects on eastern redcedar in naturally occurring hardwood leaf litter with those augmented by leaves dropped following a single application of tebuthiuron. Studies were conducted in 1988, 1989, and 1991 on a cross timbers site dominated by an overstory of post oak (Quercus stellata Wangenh.) and blackjack oak (Q. marilandica Muenchh.) and with eastern redcedar in the understory. Factors evaluated included herbicide treatment (tebuthiuron or no herbicide) and burning season (late summer or winter). Tebuthiuron at 2.2 kg a.i. Ha-1 was applied to plots (25 X 25 m) in March of the study years. In late summer, tebuthiuron-treated plots contained almost twice the 1-hr fuel loading as untreated plots. Fuel depth on untreated plots in late summer was about half that of other herbicide treatments and burning date combinations. Fuel loading on plots burned in winter was not affected by tebuthiuron treatment, and no differences in fuel consumption were detected among any treatments. Moisture content of 1-hr fuels on plots burned in winter was more than twice that of 1-hr fuels on plots burned in late summer. Fire intensity was low with all bums, and no differences in fire behavior were detected among any treatments. Crown scorch of 75% or greater on small eastern redcedar trees was considered a successful burn, and this resulted on all but the late summer-no tebuthiuron treatment. The natural log of fireline intensity explained about 47% (P<0.0006)) of the variation in fire success, and ambient air temperature explained an additional 19% (P<0.0468). Although tebuthiuron treatments effectively augmented leaf-litter fuel load by late-summer and provided a suitable fuelbed for burning, crown scorch and tree kill were not greatly improved by burning in late summer as compared to winter. We conclude that understory eastern redcedar can be controlled successfully by burning leaf-litter fuelbeds in either late fall or winter after natural leaf-fall from hardwood trees or in late summer, fall, or winter following a spring application of tebuthiuron for control of overstory hardwoods.
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Ottmar, Roger D., Andrew T. Hudak, Susan J. Prichard, Clinton S. Wright, Joseph C. Restaino, Maureen C. Kennedy, and Robert E. Vihnanek. "Pre-fire and post-fire surface fuel and cover measurements collected in the south-eastern United States for model evaluation and development – RxCADRE 2008, 2011 and 2012." International Journal of Wildland Fire 25, no. 1 (2016): 10. http://dx.doi.org/10.1071/wf15092.
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A lack of independent, quality-assured data prevents scientists from effectively evaluating predictions and uncertainties in fire models used by land managers. This paper presents a summary of pre-fire and post-fire fuel, fuel moisture and surface cover fraction data that can be used for fire model evaluation and development. The data were collected in the south-eastern United States on 14 forest and 14 non-forest sample units associated with 6 small replicate and 10 large operational prescribed fires conducted during 2008, 2011, and 2012 as part of the Prescribed Fire Combustion and Atmospheric Dynamics Research Experiment (RxCADRE). Fuel loading and fuel consumption averaged 6.8 and 4.1 Mg ha–1 respectively in the forest units and 3.0 and 2.2 Mg ha–1 in the non-forest units. Post-fire white ash cover ranged from 1 to 28%. Data were used to evaluate two fuel consumption models, CONSUME and FOFEM, and to develop regression equations for predicting fuel consumption from ash cover. CONSUME and FOFEM produced similar predictions of total fuel consumption and were comparable with measured values. Simple linear models to predict pre-fire fuel loading and fuel consumption from post-fire white ash cover explained 46 and 59% of variation respectively.
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Marsden-Smedley, JB, and WR Catchpole. "Fire Behaviour Modelling in Tasmanian Buttongrass Moorlands .I. Fuel Characteristics." International Journal of Wildland Fire 5, no. 4 (1995): 203. http://dx.doi.org/10.1071/wf9950203.
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As part of a program to develop fire management strategies for Tasmanian buttongrass moorlands fuel characteristics were sampled from a wide range of sites in western and southwestern Tasmania. Equations were developed to predict the total fuel loading and the dead fuel loading. These variables are shown in a subsequent paper to be correlated with fire behaviour. The best predictors of fuel loading were found to be geology, vegetation age (i.e. time since the last fire) and vegetation cover. Vegetation cover is difficult to assess consistently. It is shown that reasonable predictions can be made using age and geology alone. The dead fuel loading of a given age was found to be strongly related to the total fuel loading, independent of geology. Statistical techniques used to develop fuel models are discussed. Other fuel characteristics that could be used as inputs for the Rothermel fire behaviour model are also presented.
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Erdelyiová, Romana, Lucia Figuli, and Matúš Ivančo. "Prediction of fire loading on the structures using computational fluid dynamics." MATEC Web of Conferences 313 (2020): 00033. http://dx.doi.org/10.1051/matecconf/202031300033.
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The development of a fire in a large-space fire section differs significantly from the development in a small fire section. In large-space objects, to design structures under the fire load often proceeds through a performance-based approach. Advanced methods can be used in all parts of the design in predicting of the scatter of temperature field, in calculating of the heat transfer to the structure and in assessing of the mechanical behaviour of the structure or its part under the fire load. The prediction of the gas temperature in the fire compartment is crucial for the structure design. The paper is focused on selection of different fire scenarios in the large-space building. The aim is to provide background for structural design in a fire using a performance-based design. The problem is solved by using FDS (Fire Dynamics Simulator) software based on the CFD (Computational Fluid Dynamics) method.
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Lyon, Zachary D., Penelope Morgan, Camille S. Stevens-Rumann, Aaron M. Sparks, Robert F. Keefe, and Alistair M. S. Smith. "Fire behaviour in masticated forest fuels: lab and prescribed fire experiments." International Journal of Wildland Fire 27, no. 4 (2018): 280. http://dx.doi.org/10.1071/wf17145.
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Managers masticate fuels to reduce extreme fire hazards, but the effect on fire behaviour within the resulting compact fuelbeds is poorly understood. We burned 54 masticated fuelbeds in laboratory experiments one and two growing seasons after mastication and 75 masticated fuelbeds in prescribed fire experiments one growing season after treatment in three replicate Pinus ponderosa stands. Mastication treatments reduced density of trees >5 cm diameter by 30–72% resulting in total fuel depth of 6.9–13.7 cm and surface woody fuel loading of 1.0–16.0 kg m−2. Flame length and rate of spread were low and similar for coarse and fine mastication treatments and controls. Smouldering combustion lasted 6–22 h in prescribed fire experiments where fuelbeds included duff and were well mixed by machinery, compared with <2 h in the laboratory where fuelbeds did not include duff and had varying fuel moisture. Fuel consumption in the prescribed fires was highly variable, ranging from 0 to 20 cm in depth and was less from 2-year-old fuelbeds than 1-year-old fuelbeds in laboratory burns. Compared with fine mastication treatments, coarse treatments took less time to implement and were more cost-effective. Although laboratory experiments expand our understanding of burning masticated fuels under controlled conditions, they did not readily translate to prescribed burning conditions where fuels, weather and ignition patterns were more variable. This highlights the need for more laboratory experiments and in situ research that together can be used to develop much-needed, scalable predictive models of mastication combustion.
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Yu, Feng Bo, Xin Tang Wang, Ming Zhou, and Wan Zhen Wang. "Research on Fire Resistance Performance of Pre-Stressed Suspended Steel Reticulated Shell." Advanced Materials Research 163-167 (December 2010): 790–94. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.790.
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Pre-stressed steel structures with large space are widely used in stadium, exhibition hall, theater and other buildings today. In order to study the fire-resistance behavior of suspended steel lattice shell of a stadium, the method of performance-based fire resistance design is used. First of all, the stadium physical model is established and the software FDS is used to determine the heating curves of the measuring points of the large space structure for two fire scenes. Compared with international standards heating curve, the heating curves of the large space structure obtained here has characteristic of local high-temperature. The finite element software MSC.MARC is further used to simulate the fire behavior of the pre-stressed steel structure with large space, in which the fire scene with 10MW design power of fire source and 30 minutes duration of fire are considered and two loading ways that overall non-uniform temperature field loading and the local high temperature components loading are accepted. The results show that the pre-stressed steel structure with large space has good fire resistance behavior, and the overall failure will not take place for the fire scene suggested here during 30 minutes duration of fire.
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Sharma, Umesh, Virendra Kumar, Praveen Kamath, Bhupinder Singh, Pradeep Bhargava, Yogendra Singh, Asif Usmani, Jose Torero, Martin Gillie, and Pankaj Pankaj. "Testing of Full-scale RC Frame under Simulated Fire Following Earthquake." Journal of Structural Fire Engineering 5, no. 3 (August 19, 2014): 215–28. http://dx.doi.org/10.1260/2040-2317.5.3.215.
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In present study, a full-scale testing of reinforced concrete (RC) frame sub-assemblage has been investigated under fire subsequent to simulated seismic loading. First part of the sequential loading consisted of a quasi-static cyclic lateral loading corresponds to life safety level of structural performance on the test frame. In the second part of the test, a compartment fire was ignited to the pre-damaged test frame for one hour duration simulating fire following earthquake (FFE) scenario. The results showed that the first cracking was observed at the end joints of the roof beams after the frame experienced a 30 mm cyclic lateral displacement. One hour heating and eleven hour cooling was tracked and temperatures were recorded. A knocking sound was heard from the fire compartment after 5 minutes of the fire ignition. An excessive degradation of the concrete material at a number of locations of the frame sub-assemblage was observed during visual inspection after the fire test. The Nondestructive tests (NDT) were also conducted to ascertain the damage in the RC frame at the various stages of loading. The test results developed an understanding of the behaviour of RC frame sub-assemblage in FFE.
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Fan, Shengxin, Yao Zhang, and Kang Hai Tan. "Fire behaviour of deep beams under unsymmetrical loading." Engineering Structures 250 (January 2022): 113419. http://dx.doi.org/10.1016/j.engstruct.2021.113419.
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Guzmán-Carrillo, H. R., E. Jiménez Relinque, A. Manzano-Ramírez, M. Castellote, and M. Romero-Pérez. "Optimising processing conditions for the functionalisation of photocatalytic glazes by ZnO nanoparticle deposition." Materiales de Construcción 71, no. 344 (September 24, 2021): e261. http://dx.doi.org/10.3989/mc.2021.04921.
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ZnO nanospheres were synthesised and then deposited by both single- and double-fire fast processes on as-prepared ceramic substrates. The photocatalytic degradation of resazurin ink was tested under UV light. The single-fired samples did not show any evidence of photocatalytic activity because the nanoparticles melted during sintering at 1210°C. The double-fire ZnO spray-coating method successfully produced glazed materials with an active ZnO surface layer despite the high sintering temperature. The influence of experimental parameters, including the ZnO nanoparticle loading (0.03 to 1 mg/cm2) and firing temperature (650 to 800°C), were also investigated. Samples with a ZnO loading of 1 g/cm2 fired at 650°C showed the best photocatalytic activity. Increasing the temperature to 700 and 800°C led to the coalescence of ZnO nanoparticles, which reduced the photocatalytic activity.
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van Staden, Rudi, and Sam Fragomeni. "Finite element analysis of fire-damaged flexible pavement deterioration." Journal of Structural Fire Engineering 8, no. 2 (June 12, 2017): 106–16. http://dx.doi.org/10.1108/jsfe-03-2017-0024.
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Purpose This research aims to use the finite element method to examine critical distress modes in the pavement layers due to changes in the structural properties brought upon by fire damage. Design/methodology/approach A full dynamic analysis is performed to replicate heavy vehicle axle wheel loads travelling over a pavement section. Findings Results show a 72 per cent decrease in the number of load repetitions which a fire-damaged pavement can experience before fatigue cracking of the asphalt. Further, there is a 51 per cent decrease in loading cycles of the subgrade before rutting of the fire-damaged system. Originality/value Fatigue of asphalt and deformation of subgrade from repeated vehicular loading are the most common failure mechanisms, and major attributors to pavement maintenance and rehabilitation costs. Pavement analysis has always been concentrated on evaluating deterioration under regularly occurring operational conditions. However, the impact of one-off events, such as vehicle petroleum fires, has not been evaluated for the effects on deterioration.
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Bouras, Yanni, and Zora Vrcelj. "In-plane stability of shallow concrete arches under fire." Journal of Structural Fire Engineering 11, no. 1 (January 8, 2020): 1–21. http://dx.doi.org/10.1108/jsfe-11-2018-0039.
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Purpose Concrete arch structures are commonly constructed for various civil engineering applications. Despite their frequent use, there is a lack of research on the response and performance of concrete arches when subjected to fire loading. Hence, this paper aims to investigate the response and in-plane failure modes of shallow circular concrete arches subjected to mechanical and fire loading. Design/methodology/approach This study is conducted through the development of a three-dimensional finite element (FE) model in ANSYS. The FE model is verified by comparison to a non-discretisation numerical model derived herein and the reduced modulus buckling theory, both used for the non-linear inelastic analysis of shallow concrete arches subjected to uniformly distributed radial loading and uniform temperature field. Both anti-symmetric and symmetric buckling modes are examined, with analysis of the former requiring geometric imperfection obtained by an eigenvalue buckling analysis. Findings The FE results show that anti-symmetric bifurcation buckling is the dominant failure mode in shallow concrete arches under mechanical and fire loading. Additionally, parametric studies are presented which illustrate the influence of various parameters on fire resistance time. Originality/value Fire response of concrete arches has not been reported in the open literature. The authors have previously investigated the stability of shallow concrete arches subjected to mechanical and uniform thermal loading. It was found that temperature greatly reduced the buckling loads of concrete arches. However, this study was limited to the simplifying assumptions made which include elastic material behaviour and uniform temperature loading. The present study provides a realistic insight into the fire response and stability of shallow concrete arches. The findings herein may be adopted in the fire design of shallow concrete arches.
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Syphard, Alexandra D., Volker C. Radeloff, Nicholas S. Keuler, Robert S. Taylor, Todd J. Hawbaker, Susan I. Stewart, and Murray K. Clayton. "Predicting spatial patterns of fire on a southern California landscape." International Journal of Wildland Fire 17, no. 5 (2008): 602. http://dx.doi.org/10.1071/wf07087.
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Humans influence the frequency and spatial pattern of fire and contribute to altered fire regimes, but fuel loading is often the only factor considered when planning management activities to reduce fire hazard. Understanding both the human and biophysical landscape characteristics that explain how fire patterns vary should help to identify where fire is most likely to threaten values at risk. We used human and biophysical explanatory variables to model and map the spatial patterns of both fire ignitions and fire frequency in the Santa Monica Mountains, a human-dominated southern California landscape. Most fires in the study area are caused by humans, and our results showed that fire ignition patterns were strongly influenced by human variables. In particular, ignitions were most likely to occur close to roads, trails, and housing development but were also related to vegetation type. In contrast, biophysical variables related to climate and terrain (January temperature, transformed aspect, elevation, and slope) explained most of the variation in fire frequency. Although most ignitions occur close to human infrastructure, fires were more likely to spread when located farther from urban development. How far fires spread was ultimately related to biophysical variables, and the largest fires in southern California occurred as a function of wind speed, topography, and vegetation type. Overlaying predictive maps of fire ignitions and fire frequency may be useful for identifying high-risk areas that can be targeted for fire management actions.
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Kodur, Venkatesh, and Mohannad Z. Naser. "Effect of local instability on fire response of steel beams." PSU Research Review 1, no. 2 (August 14, 2017): 170–79. http://dx.doi.org/10.1108/prr-05-2017-0025.
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Purpose This purpose of this paper is to quantify the effect of local instability arising from high shear loading on response of steel girders subjected to fire conditions. Design/methodology/approach A three-dimensional nonlinear finite element model able to evaluate behavior of fire-exposed steel girders is developed. This model, is capable of predicting fire response of steel girders taking into consideration flexural, shear and deflection limit states. Findings Results obtained from numerical studies show that shear capacity can degrade at a higher pace than flexural capacity under certain loading scenarios, and hence, failure can result from shear effects prior to attaining failure in flexural mode. Originality/value The developed model is unique and provides valuable insight (and information) to the fire response of typical hot-rolled steel girder subjected to high shear loading.
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Morici, Kat E., and John D. Bailey. "Long-Term Effects of Fuel Reduction Treatments on Surface Fuel Loading in the Blue Mountains of Oregon." Forests 12, no. 10 (September 25, 2021): 1306. http://dx.doi.org/10.3390/f12101306.
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Fire exclusion and a lengthening fire season has resulted in an era of megafires. Fuel reduction treatments in forested ecosystems are designed to guard against future extreme wildfire behavior. Treatments create a heterogenous landscape and facilitate ecosystem function and resilience in fire-adapted forests of the western United States. Despite widespread recognition that repeated fuel treatments are needed to maintain desired stand characteristics over time, few field studies have evaluated treatment longevity. The Blue Mountains Fire and Fire Surrogate site in northeastern Oregon presented an opportunity to investigate woody fuel loading 15–17 years after four treatments: mechanical thin, prescribed burn, both thin and burn, and no treatment control. The principal findings were: (1) fine fuel load 15 years post-burn remained slightly below pre-treatment values; (2) rotten coarse fuel load was reduced post-burn, but sound coarse fuel was not altered by any active treatment; and (3) total woody fuel load 15–17 years post-treatment was similar to pre-treatment values. Understanding surface fuel loading is essential for predicting fire behavior. Overall, the effects of fuel reduction treatments on woody surface fuels were transitory in dry mixed conifer forests. Frequent maintenance treatments are recommended to protect values at risk in areas with high fire hazards. Quantifying the persistence of changes in forest conditions aids in the planning and analysis of future fuel treatments, along with scheduling maintenance of existing treated areas.
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Raymond, Crystal L., and David L. Peterson. "Fuel treatments alter the effects of wildfire in a mixed-evergreen forest, Oregon, USA." Canadian Journal of Forest Research 35, no. 12 (December 1, 2005): 2981–95. http://dx.doi.org/10.1139/x05-206.
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We had the rare opportunity to quantify the relationship between fuels and fire severity using prefire surface and canopy fuel data and fire severity data after a wildfire. The study area is a mixed-evergreen forest of southwestern Oregon with a mixed-severity fire regime. Modeled fire behavior showed that thinning reduced canopy fuels, thereby decreasing the potential for crown fire spread. The potential for crown fire initiation remained fairly constant despite reductions in ladder fuels, because thinning increased surface fuels, which contributed to greater surface fire intensity. Thinning followed by underburning reduced canopy, ladder, and surface fuels, thereby decreasing surface fire intensity and crown fire potential. However, crown fire is not a prerequisite for high fire severity; damage to and mortality of overstory trees in the wildfire were extensive despite the absence of crown fire. Mortality was most severe in thinned treatments (80%100%), moderate in untreated stands (53%54%), and least severe in the thinned and underburned treatment (5%). Thinned treatments had higher fine-fuel loading and more extensive crown scorch, suggesting that greater consumption of fine fuels contributed to higher tree mortality. Fuel treatments intended to minimize tree mortality will be most effective if both ladder and surface fuels are treated.
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Kane, Jeffrey M., J. Morgan Varner, and Eric E. Knapp. "Novel fuelbed characteristics associated with mechanical mastication treatments in northern California and south-western Oregon, USA." International Journal of Wildland Fire 18, no. 6 (2009): 686. http://dx.doi.org/10.1071/wf08072.
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Mechanically masticated fuelbeds are distinct from natural or logging slash fuelbeds, with different particle size distributions, bulk density, and particle shapes, leading to challenges in predicting fire behavior and effects. Our study quantified some physical properties of fuel particles (e.g. squared quadratic mean diameter, proportion of non-cylindrical particles) and surface fuel loading with planar intercept and plot-based methods in 10 mechanically masticated sites in northern California and south-western Oregon. Total woody fuel load differed among masticated sites, ranging from 15.3 to 63.4 Mg ha–1, with the majority of the load concentrated in the 10-h (53.7%) and 1-h (29.2%) time-lag classes. Masticated fuels were densely packed, with total depths ranging from 4.6 to 8.0 cm and fuelbed bulk densities ranging from 45.9 to 115.3 kg m–3. To accurately quantify loading in masticated fuelbeds, we recommend using a hybrid methodology, where 1-h and 10-h fuel loadings are estimated using a plot-based method and 100-h and 1000-h fuel loadings are estimated using the standard planar intercept method. Most masticated fuelbeds differed in loading by fuel class and fuelbed depth, when compared with existing natural and slash-based fuelbeds, suggesting new fire behavior fuel models specific to masticated fuelbeds may be warranted.
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Cai, Longyan, Hong S. He, Yu Liang, Zhiwei Wu, and Chao Huang. "Analysis of the uncertainty of fuel model parameters in wildland fire modelling of a boreal forest in north-east China." International Journal of Wildland Fire 28, no. 3 (2019): 205. http://dx.doi.org/10.1071/wf18083.
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Fire propagation is inevitably affected by fuel-model parameters during wildfire simulations and the uncertainty of the fuel-model parameters makes forecasting accurate fire behaviour very difficult. In this study, three different methods (Morris screening, first-order analysis and the Monte Carlo method) were used to analyse the uncertainty of fuel-model parameters with FARSITE model. The results of the uncertainty analysis showed that only a few fuel-model parameters markedly influenced the uncertainty of the model outputs, and many of the fuel-model parameters had little or no effect. The fire-spread rate is the driving force behind the uncertainty of other fire behaviours. Thus, the highly uncertain fuel-model parameters associated with spread rate should be used cautiously in wildfire simulations. Monte Carlo results indicated that the relationship between model input and output was non-linear and neglecting fuel-model parameter uncertainty of the model would magnify fire behaviours. Additionally, fuel-model parameters have high input uncertainty. Therefore, fuel-model parameters must be calibrated against actual fires. The highly uncertain fuel-model parameters with high spatial-temporal variability consisted of fuel-bed depth, live-shrub loading and 1-h time-lag loading are preferentially chosen as parameters to calibrate several wildfires.
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Hu, Ying, Zi Xiong Chen, Ming Kui Xiao, Ying Ming Li, and Yong Jun Liu. "Assessment of Connection Ductility in Fire." Applied Mechanics and Materials 353-356 (August 2013): 2305–12. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.2305.
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Catenary action has been regarded as a viable load-carrying mechanism in fire for providing structural robustness to steel framed buildings, and this loading mechanism heavily relies on connection strength and ductility under exceptional loading conditions. However, the current code of practice has no detailed guidance on estimation of the connection ductility. This paper is dedicated to demonstration of how to quantify connection ductility in a fire or non-fire situation through the component-based approach. Connection ductility has been evaluated with emphasis on elongation and strength of connection components in each bolt row, and response of brittle components has been identified as an index for connection ductility and failure mechanism in a fire situation.
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Stevens-Rumann, Camille, Kristen Shive, Peter Fulé, and Carolyn H. Sieg. "Pre-wildfire fuel reduction treatments result in more resilient forest structure a decade after wildfire." International Journal of Wildland Fire 22, no. 8 (2013): 1108. http://dx.doi.org/10.1071/wf12216.
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Increasing size and severity of wildfires have led to an interest in the effectiveness of forest fuels treatments on reducing fire severity and post-wildfire fuels. Our objective was to contrast stand structure and surface fuel loadings on treated and untreated sites within the 2002 Rodeo–Chediski Fire area. Data from 140 plots on seven paired treated–untreated sites indicated that pre-wildfire treatments reduced fire severity compared with untreated sites. In 2011, coarse woody debris loading (woody material>7.62cm in diameter) was 257% higher and fine woody debris (woody material<7.62cm) was 152% higher on untreated sites than on treated sites. Yet, in spite of higher levels of coarse woody debris on untreated sites, loadings did not exceed recommended ranges based on published literature and many treated sites fell below recommendations. By 2011, basal area and stand density on treated sites and stand density on untreated sites met management guidelines for ponderosa pine forests, but untreated sites had basal areas well below recommendations. Snags declined over this period and only three plots had snags that met minimum size and density requirements for wildlife habitat by 2011. The effects of pre-wildfire treatments are long-lasting and contribute to changes in both overstorey and understorey fuel complexes.
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Nelson, Ralph M., and J. Kevin Hiers. "The influence of fuelbed properties on moisture drying rates and timelags of longleaf pine litter." Canadian Journal of Forest Research 38, no. 9 (September 2008): 2394–404. http://dx.doi.org/10.1139/x08-078.
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Fire managers often model pine needles as 1 h timelag fuels, but fuelbed properties may significantly change the rate at which needles exchange moisture with the atmosphere. The problem of determining whether moisture loss from fine fuels is being controlled by individual particles or by the fuelbed remains unresolved. Results from this laboratory experiment indicate that first-period timelags of longleaf pine ( Pinus palustris Mill.) needles are altered by fuelbed loading and needle arrangement. Timelags of individual needles ranged from 3.3 to 5.3 h; timelags of beds of vertically oriented needles (4.4 to 8.6 h) approximated those of individual particles, but were slightly influenced by loading. Beds of horizontal needles dried with load-dependent timelags that varied from 6.5 to 31.6 h. Fuel loads ranged from 0.04 (for individual particles) to 1.07 kg·m–2. We report a new metric, the area drying rate, which is analogous to a unit-area burning rate. For beds of flat needles, plots of the area drying rate versus fuel load illustrate a transition from control by individual particles to control by the bed structure when fuel loading is approximately 0.33 kg·m–2. Beds of vertical needles were particle controlled. Results should be useful to fire managers when modeling fire behavior.
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Ibraheem, Omer Farooq, and Hafssa Ali Abdullah. "Behavior of Steel Beams Subjected to Bending and Shear Loading Under Localized Fire Conditions." Tikrit Journal of Engineering Sciences 29, no. 3 (November 10, 2022): 82–90. http://dx.doi.org/10.25130/tjes.29.3.9.
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Civil structures were designed to carry a variety of loading during their service life, including fire hazards. As a result, providing fire safety to structural members is one of the most important tasks in civil infrastructure design. Steel structural members are subject to fire-induced damage or collapse due to their high heat conductivity and quick loss of strength and stiffness qualities. Furthermore, the failure in steel beams under the combined effects of bending, shear, and fire loading is poorly understood in the literature. A present study consists of experimental investigations on the fire response of steel beams under bending and shear dominant loading. The specimens have a constant length of 1250 mm. The total depth of the specimens was changed according to the section chosen: 4 in, 6 in, and 8 in (10 cm, 15 cm, and 20 cm). The results of tests show that beams can fail suddenly due to a high drop in yield and ultimate strength of the steel beam. the increase in temperature degree reduced greatly the yield and ultimate flexural strength of the steel beams with different sizes (for all groups). This reduction reached at some times to 50% for the ultimate strength capacity of the specimen. Shear strength is also affected greatly by fire exposure and the reduction reached to about 38%. Furthermore, the design strength capacity can only tolerate loads at low temperatures. This reduction in strength was noted under flexural and shear dominant loading. Moreover, the design strength capacity can withstand against loading at low-temperature degrees only.
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Bénichou, Noureddine, Hossein Mostafaei, Mark F. Green, and Kevin Hollingshead. "The impact of fire on seismic resistance of fibre reinforced polymer strengthened concrete structural systems." Canadian Journal of Civil Engineering 40, no. 11 (November 2013): 1044–49. http://dx.doi.org/10.1139/cjce-2012-0521.
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This paper presents the results of a research project to study the seismic resistance of fibre reinforced polymer (FRP) strengthened concrete members after fire exposure. Specifically, the paper presents results of FRP strengthened reinforced concrete columns exposed to a standard fire including temperatures measured during the test and a discussion of the loads applied to the columns. Finally, the paper also presents the impact of lateral loading on structural columns after fire to assess the effectiveness of structural resistance of fire-damaged FRP strengthened building elements in case of an earthquake. Numerical models to simulate the lateral behaviour are presented and the predictions are compared to the test results. Since the FRP strengthened columns were insulated with fire protection, the lateral load resistance of the unstrengthened column was reduced by less than 5% due to fire exposure.
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Weise, David R., Xiangyang Zhou, Lulu Sun, and Shankar Mahalingam. "Fire spread in chaparral—'go or no-go?'." International Journal of Wildland Fire 14, no. 1 (2005): 99. http://dx.doi.org/10.1071/wf04049.
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Current fire models are designed to model the spread of a linear fire front in dead, small-diameter fuels. Fires in predominantly living vegetation account for a large proportion of annual burned area in the United States. Prescribed burning is used to manage living fuels; however, prescribed burning is currently conducted under conditions that result in marginal burning. We do not understand quantitatively the relative importance of the fuel and environmental variables that determine spread in live vegetation. To address these weaknesses, laboratory fires have been burned to determine the effects of wind, slope, moisture content and fuel characteristics on fire spread in fuel beds of common chaparral species. Four species (Adenostoma fasciculatum, Ceanothus crassifolius, Quercus berberidifolia, Arctostaphylos parryana), two wind velocities (0 and 2 m s−1) and two fuel bed depths (20 and 40 cm) were used. Oven-dry moisture content of fine fuels (<0.63 cm diameter) ranged from 0.09 to 1.06. Seventy of 125 fires successfully propagated the length (2.0 m) of the elevated fuel bed. A logistic model to predict the probability of successful fire spread was developed using stepwise logistic regression. The variables selected to predict propagation were wind velocity, slope percent, moisture content, fuel loading, species and air temperature. Air temperature and species terms were removed from the model for parsimony. The final model correctly classified 94% of the observations. Comparison of results with an empirical decision matrix for prescribed burning in chaparral suggested some agreement between the laboratory data and the empirical tool.
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Stott, Philip. "Combustion in tropical biomass fires: a critical review." Progress in Physical Geography: Earth and Environment 24, no. 3 (September 2000): 355–77. http://dx.doi.org/10.1177/030913330002400303.
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Despite the publication of a number of recent books, mainly edited compilations, on both fire ecology in general and, more specifically, fire ecology in the tropics, it remains difficult to obtain accessible overviews of many aspects of the subject. This is particularly so with regard to tropical biomass fires. The review presented here attempts to fill this gap with regard to the subjects of ignition and combustion in such fires, focusing on natural and anthropogenic ignition sources, the processes of ignition, the stages of combustion, combustion efficiency, fuel type, fuel flammability, fuel preparation, fuel loading and oxygenation of the environment.
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Garashchenko, A. N., S. P. Antonov, A. I. Danilov, V. V. Pavlov, and N. S. Novikov. "Analyzing the fire performance of concrete columns and slabs under loading and using options, preventing explosive spalling to ensure the pre-set fire resistance." Pozharovzryvobezopasnost/Fire and Explosion Safety 31, no. 3 (July 24, 2022): 45–64. http://dx.doi.org/10.22227/0869-7493.2022.31.03.45-64.
Full textAbstract:
Introduction. The authors focus on preventing the explosive spalling of concrete and the fireproofing of reinforced concrete structures. The relevance of this issue is explained by the insufficient number of fire tests of such structures under loading and thermal engineering calculations, needed for an objective analysis of testing results.Goal and objectives. The authors analyze the results of a series of fire tests, involving concrete columns and slabs with and without polypropylene microfiber, if no fireproofing is applied, as well as the results of the same tests involving the same items fireproofed by plates or plaster.Methods. The fire resistance of full-scale specimens of concrete was evaluated according to a standardized testing in a fire furnace under loading. It encompasses additional thermocouple measurements used to make a thermal engineering analysis. The analysis entailed both one- and two-dimensional problem formulations, methods and programmes for the numerical computation of non-stationary temperature fields in fireproof structures.Results. New data, obtained in the course of the fire experiments, show the efficiency of the polypropylene microfiber used to prevent the explosive spalling of concrete. The fire resistance limit is R 120 and R 150 under constant static loading. The fire resistance limit of similar structures, fireproofed by PROSASK Firepanel plates or IGNIS LIGHT plaster, was demonstrated. The specimens show the efficiency of methods and programmes for the one- and two-dimensional numerical analysis of non-stationary temperature fields in fireproof structures. The calculation results are presented for various fireproofing options.Conclusions. The testing results and their thermal analysis represent important items of information necessary to ensure the fire safety and the pre-set fire resistance of concrete structures under loading. They can also be used to outline the development pattern of this experimental and theoretical research project. The efficiency of thermal engineering calculations as a tool for evaluating fire protection parameters and the fire resistance of concrete structures is demonstrated, also as an option to reduce the number of expensive fire tests.