Using bolts as shear connectors of the steel–concrete composite beams enables prefabricated assembly and makes it possible to demountable and reuse the prefabricated components. However, studies on the fire resistance of prefabricated demountable composite beams (PDCBs) connected by bolts are limited. In this paper, four full-scale fire resistance tests were conducted to investigate the fire resistance of PDCBs connected by shear bolts with profiled sheet ribs parallel to the steel beam. Experimental observations, heating curves, deformation curves, and critical temperatures of specimens were obtained through fire-resistant tests. Test results show that the shear failure of bolted connectors occurred in the partially connected PDCBs instead of in the fully connected ones. Under the same load ratio, the fire resistance limit of PDCBs with fire protection was 4.4 times that of PDCBs without fire protection. The temperatures of the upper flanges of the steel beams in the PDCBs were overestimated by the existing codes. Moreover, numerical heat transfer analysis was carried out to investigate the effect of concrete slab thickness, concrete moisture content and steel beam upper flange dimensions on the temperature distribution of the steel beam upper flange. Finally, based on the results, relevant recommendations are made for the method of calculating the temperature of the steel beam upper flange in the PDCBs.
{"title":"Study on Fire Resistance of Prefabricated Demountable Composite Beams Using Bolted Shear Connectors","authors":"Mengjie Wang, Guobiao Lou, Zhaohan Wen, Binhui Jiang, Yongchang Wang, Yaqiang Jiang","doi":"10.1007/s10694-023-01533-1","DOIUrl":"https://doi.org/10.1007/s10694-023-01533-1","url":null,"abstract":"<p>Using bolts as shear connectors of the steel–concrete composite beams enables prefabricated assembly and makes it possible to demountable and reuse the prefabricated components. However, studies on the fire resistance of prefabricated demountable composite beams (PDCBs) connected by bolts are limited. In this paper, four full-scale fire resistance tests were conducted to investigate the fire resistance of PDCBs connected by shear bolts with profiled sheet ribs parallel to the steel beam. Experimental observations, heating curves, deformation curves, and critical temperatures of specimens were obtained through fire-resistant tests. Test results show that the shear failure of bolted connectors occurred in the partially connected PDCBs instead of in the fully connected ones. Under the same load ratio, the fire resistance limit of PDCBs with fire protection was 4.4 times that of PDCBs without fire protection. The temperatures of the upper flanges of the steel beams in the PDCBs were overestimated by the existing codes. Moreover, numerical heat transfer analysis was carried out to investigate the effect of concrete slab thickness, concrete moisture content and steel beam upper flange dimensions on the temperature distribution of the steel beam upper flange. Finally, based on the results, relevant recommendations are made for the method of calculating the temperature of the steel beam upper flange in the PDCBs.</p>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139474605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-13DOI: 10.1007/s10694-023-01522-4
Abstract
In order for detection of a fire in fields, it is effective to detect smoke since it often behaves as a precursor of the fire. One preferable way for early detection is to use visual information from outdoor cameras that widely monitor the filed. There have been many attempts to detect smokes via optical sensors on digital cameras using optical flow methods, but not fully successful from practical-use aspects. It is because the area of smokes occupying on the footage by outdoor cameras is not necessarily large enough. Moreover, in case of urban cities, discrimination of the smokes from other moving objects such as cars, trees and turbines is not easy. Herein we propose a novel method to detect daytime smokes based on variance of optical flow and characteristics of HSV (hue-saturation-value) color. We apply the method to a set of footage of three days obtained in an industrial zone in Japan. Successful results are obtained as over 90% of smokes are detected. Notable is that this method is independent of solar radiation conditions on sunny and cloudy days.
{"title":"A Daytime Smoke Detection Method Based on Variances of Optical Flow and Characteristics of HSV Color on Footage from Outdoor Camera in Urban City","authors":"","doi":"10.1007/s10694-023-01522-4","DOIUrl":"https://doi.org/10.1007/s10694-023-01522-4","url":null,"abstract":"<h3>Abstract</h3> <p>In order for detection of a fire in fields, it is effective to detect smoke since it often behaves as a precursor of the fire. One preferable way for early detection is to use visual information from outdoor cameras that widely monitor the filed. There have been many attempts to detect smokes via optical sensors on digital cameras using optical flow methods, but not fully successful from practical-use aspects. It is because the area of smokes occupying on the footage by outdoor cameras is not necessarily large enough. Moreover, in case of urban cities, discrimination of the smokes from other moving objects such as cars, trees and turbines is not easy. Herein we propose a novel method to detect daytime smokes based on variance of optical flow and characteristics of HSV (hue-saturation-value) color. We apply the method to a set of footage of three days obtained in an industrial zone in Japan. Successful results are obtained as over 90% of smokes are detected. Notable is that this method is independent of solar radiation conditions on sunny and cloudy days.</p>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139459192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electrical cables are one of the main fire hazards in nuclear power plants (NPPs) and in many other industrial sectors. To assess the potential damages of the cable fires, models are required to forecast the fire spread over multiple cable trays and the resulting heat release rate. A new test device, called CISCCO, was developed to conduct flame spread experiments on a preheated horizontal cable layer to support the development and validation of the models. The characteristics of the CISCCO device are first presented before the description of four series of experiments that first investigated the temperature dependence of the flame spread velocity. The series involved a cable layer composed of either a polyvinyl chloride (PVC)-based cable, named PVC cable or a halogen free flame retardant (HFFR) poly(ethylene–vinyl acetate)/polyethylene-based cable, labelled HFFR cable. Temperature measurements performed in the solid phase (cable outer sheath) and in the gas phase (above the cable layer) allowed to assess the preheated cable layer temperature and the flame spread velocity. A first attempt of flame heat flux measurements was also conducted in this work. All series highlighted a temperature dependence of the flame spread velocity according to experimental power laws. The flame spread velocities were measured higher for the PVC cable (0 to 5.5 mm/s) than for the HFFR cable (0 to 1.5 mm/s) while the related preheated cable temperatures suitable for spreading were measured lower for the former (170 to 250°C) than for the latter (280 to 370°C). Finally, one of the four test series that used the PVC cable and implemented heat release rate measurements, revealed that the cable fire growth rate is also temperature dependent according to a power law and is linearly correlated to the flame spread velocity.
{"title":"Flame Spread Experiments on a Horizontal Preheated Cable Layer","authors":"Pascal Zavaleta, Romain Meinier, Sylvain Suard, Rodolphe Sonnier, Laurent Ferry","doi":"10.1007/s10694-023-01521-5","DOIUrl":"https://doi.org/10.1007/s10694-023-01521-5","url":null,"abstract":"<p>Electrical cables are one of the main fire hazards in nuclear power plants (NPPs) and in many other industrial sectors. To assess the potential damages of the cable fires, models are required to forecast the fire spread over multiple cable trays and the resulting heat release rate. A new test device, called CISCCO, was developed to conduct flame spread experiments on a preheated horizontal cable layer to support the development and validation of the models. The characteristics of the CISCCO device are first presented before the description of four series of experiments that first investigated the temperature dependence of the flame spread velocity. The series involved a cable layer composed of either a polyvinyl chloride (PVC)-based cable, named PVC cable or a halogen free flame retardant (HFFR) poly(ethylene–vinyl acetate)/polyethylene-based cable, labelled HFFR cable. Temperature measurements performed in the solid phase (cable outer sheath) and in the gas phase (above the cable layer) allowed to assess the preheated cable layer temperature and the flame spread velocity. A first attempt of flame heat flux measurements was also conducted in this work. All series highlighted a temperature dependence of the flame spread velocity according to experimental power laws. The flame spread velocities were measured higher for the PVC cable (0 to 5.5 mm/s) than for the HFFR cable (0 to 1.5 mm/s) while the related preheated cable temperatures suitable for spreading were measured lower for the former (170 to 250°C) than for the latter (280 to 370°C). Finally, one of the four test series that used the PVC cable and implemented heat release rate measurements, revealed that the cable fire growth rate is also temperature dependent according to a power law and is linearly correlated to the flame spread velocity.</p>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139422232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.1007/s10694-023-01525-1
Abstract
With climate change and the ever-drier climate, the issue of wildfires is becoming increasingly prominent, generating growing interest in the study of wildfires. The majority of the ongoing research is focused on surface wildland fuels with particular emphasis on dead and usually dry fuel. These insights are difficult to transpose to live fuels, particularly to crown fires. The flammability properties of dead and dry forest fuels are of little significance for understanding the onset and spread of crown fires. Hence, research regarding the flammability properties of fresh forest vegetation is very sparse. The same observation applies to crown fires, despite the fact that this type of wildfires is devastating, difficult to suppress, and usually having dramatic consequences. The aim of this paper is to determine how moisture dynamics of live crown samples (terminal parts of basal branches) of two coniferous species, Abies alba and Picea abies, influence their flammability properties. Experiments were performed in an adapted mass loss calorimeter with a custom-made sample holder in order to mimic the scenario of initiation of crown fires (surface to crown fire interface). Tests were performed with heat flux values of 50, 60, and 70 kW/m2 and with different moisture levels. At all heat flux values, the results show an increasing trend for the peak heat release rate when moisture content is reduced. A. alba samples reach higher peak release rates in comparison with P. abies samples. At heat fluxes of 50 kW/m2 and 60 kW/m2, fresh A. alba samples take longer to ignite than the P. abies samples. At the heat flux of 70 kW/m2, for the set of analyzed moisture contents, the ignition time interval for the A. alba samples is shorter than for the P. abies samples. The results of the principal component analysis (PCA) show that variables such as time to ignition (TTI), peak heat release rate (PHRR), and mean heat release rate (mean HRR) best describe the ignitability of the analyzed conifer samples.
{"title":"Transition from Surface to Crown Fires: Effects of Moisture Content","authors":"","doi":"10.1007/s10694-023-01525-1","DOIUrl":"https://doi.org/10.1007/s10694-023-01525-1","url":null,"abstract":"<h3>Abstract</h3> <p>With climate change and the ever-drier climate, the issue of wildfires is becoming increasingly prominent, generating growing interest in the study of wildfires. The majority of the ongoing research is focused on surface wildland fuels with particular emphasis on dead and usually dry fuel. These insights are difficult to transpose to live fuels, particularly to crown fires. The flammability properties of dead and dry forest fuels are of little significance for understanding the onset and spread of crown fires. Hence, research regarding the flammability properties of fresh forest vegetation is very sparse. The same observation applies to crown fires, despite the fact that this type of wildfires is devastating, difficult to suppress, and usually having dramatic consequences. The aim of this paper is to determine how moisture dynamics of live crown samples (terminal parts of basal branches) of two coniferous species, <em>Abies alba</em> and <em>Picea abies</em>, influence their flammability properties. Experiments were performed in an adapted mass loss calorimeter with a custom-made sample holder in order to mimic the scenario of initiation of crown fires (surface to crown fire interface). Tests were performed with heat flux values of 50, 60, and 70 kW/m<sup>2</sup> and with different moisture levels. At all heat flux values, the results show an increasing trend for the peak heat release rate when moisture content is reduced. <em>A. alba</em> samples reach higher peak release rates in comparison with <em>P. abies</em> samples. At heat fluxes of 50 kW/m<sup>2</sup> and 60 kW/m<sup>2</sup>, fresh <em>A. alba</em> samples take longer to ignite than the <em>P. abies</em> samples. At the heat flux of 70 kW/m<sup>2</sup>, for the set of analyzed moisture contents, the ignition time interval for the <em>A. alba</em> samples is shorter than for the <em>P. abies</em> samples. The results of the principal component analysis (PCA) show that variables such as time to ignition (TTI), peak heat release rate (PHRR), and mean heat release rate (mean HRR) best describe the ignitability of the analyzed conifer samples.</p>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139410627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-08DOI: 10.1007/s10694-023-01531-3
Xiaolian Li, Jie Li, Milad Haghani
Applications of Remote Sensing (RS) has recently attracted increasing attention in wildfire research. In this study, a total of 2842 documents related to remote sensing-based wildfire research (RS-based wildfire research) have been collected from Science Citation Index Expanded database in the Web of Science Core Collection (WOS CC) for analyzing its development and currently popular concerns by using VOSviewer. Results show that the publications exhibit an exponential increase on the whole since 2000. It is identified that the most productive journal is Remote Sensing, with 235 published articles, accounting for 8.27% of the total research publications. The United States is the most prolific country with 1200 documents. NASA, USDA Forest Service and University of Maryland that affiliated to USA are the top three institutions with more than 100 publications. The co-authorship network shows that the application of remote sensing to wildfire attracts a large number of researchers’ attention. The topic analysis demonstrates that the hot topics cover the whole process of wildfire. The reference analysis and co-citation network also confirm this finding.
最近,遥感技术(RS)在野火研究中的应用日益受到关注。本研究从 Web of Science Core Collection(WOS CC)中的 Science Citation Index Expanded 数据库中收集了 2842 篇与基于遥感的野火研究(RS-based wildfire research)相关的文献,利用 VOSviewer 分析了其发展情况和当前的热门关注点。结果表明,自 2000 年以来,这些出版物总体上呈指数增长。研究发现,最有成果的期刊是《遥感》,共发表 235 篇文章,占研究论文总数的 8.27%。美国是发表文献最多的国家,有 1200 篇文献。美国国家航空航天局(NASA)、美国农业部林业局(USDA Forest Service)和美国马里兰大学(University of Maryland)是发表论文数量最多的三个机构,均超过 100 篇。合著网络显示,遥感技术在野火中的应用吸引了大量研究人员的关注。主题分析表明,热点话题涵盖了野火的整个过程。参考文献分析和合著网络也证实了这一结论。
{"title":"Application of Remote Sensing Technology in Wildfire Research: Bibliometric Perspective","authors":"Xiaolian Li, Jie Li, Milad Haghani","doi":"10.1007/s10694-023-01531-3","DOIUrl":"https://doi.org/10.1007/s10694-023-01531-3","url":null,"abstract":"<p>Applications of Remote Sensing (RS) has recently attracted increasing attention in wildfire research. In this study, a total of 2842 documents related to remote sensing-based wildfire research (RS-based wildfire research) have been collected from Science Citation Index Expanded database in the Web of Science Core Collection (WOS CC) for analyzing its development and currently popular concerns by using VOSviewer. Results show that the publications exhibit an exponential increase on the whole since 2000. It is identified that the most productive journal is Remote Sensing, with 235 published articles, accounting for 8.27% of the total research publications. The United States is the most prolific country with 1200 documents. NASA, USDA Forest Service and University of Maryland that affiliated to USA are the top three institutions with more than 100 publications. The co-authorship network shows that the application of remote sensing to wildfire attracts a large number of researchers’ attention. The topic analysis demonstrates that the hot topics cover the whole process of wildfire. The reference analysis and co-citation network also confirm this finding.</p>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139410100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-08DOI: 10.1007/s10694-023-01532-2
H. S. Zhen, X. Q. Shang, X. Y. Liu, Z. L. Wei, Y. L. Wang
So far too long, people have been working hard to develop fire prevention measures to deal with lithium ion battery (LIB) fires. LIB fires have a high calorific value, a rapid burning and spread speed and a high risk of re-ignition and explosion. Under thermal runaway, LIB fires develop from the inside out, preventing fire extinguishing agents from entering the interior of LIB, thus resulting in low extinguishing efficiency or even failure of the extinguishing agents. Based on the principle of ‘isolation and stifling’, fire-blocking blanket can effectively inhibit the spread of fire, suppress the combustion intensity and reduce the smoke emission. This paper digs into the detailed performance requirements of fire blanket to block LIB fires. By conducting laboratory tests to mimic LIB fires, the candidate materials including fiber materials, woven textile and woven fabrics with organic coatings are systematically investigated. Performance of the materials are evaluated, including fire resistance, thermal insulation, tensile strength at break and blast resistance, respectively. The testing results help to screen out the best material for LIB fire blanket, and high-silica glass fiber coated by polyurethane has the best thermal and mechanical properties among all materials tested. This paper also presents a three-layer structured design of blanket, which can pass all the tests proposed.
{"title":"Performance-Focused Analysis of Fire-Blocking Blanket for Lithium Ion Battery Fires","authors":"H. S. Zhen, X. Q. Shang, X. Y. Liu, Z. L. Wei, Y. L. Wang","doi":"10.1007/s10694-023-01532-2","DOIUrl":"https://doi.org/10.1007/s10694-023-01532-2","url":null,"abstract":"<p>So far too long, people have been working hard to develop fire prevention measures to deal with lithium ion battery (LIB) fires. LIB fires have a high calorific value, a rapid burning and spread speed and a high risk of re-ignition and explosion. Under thermal runaway, LIB fires develop from the inside out, preventing fire extinguishing agents from entering the interior of LIB, thus resulting in low extinguishing efficiency or even failure of the extinguishing agents. Based on the principle of ‘isolation and stifling’, fire-blocking blanket can effectively inhibit the spread of fire, suppress the combustion intensity and reduce the smoke emission. This paper digs into the detailed performance requirements of fire blanket to block LIB fires. By conducting laboratory tests to mimic LIB fires, the candidate materials including fiber materials, woven textile and woven fabrics with organic coatings are systematically investigated. Performance of the materials are evaluated, including fire resistance, thermal insulation, tensile strength at break and blast resistance, respectively. The testing results help to screen out the best material for LIB fire blanket, and high-silica glass fiber coated by polyurethane has the best thermal and mechanical properties among all materials tested. This paper also presents a three-layer structured design of blanket, which can pass all the tests proposed.</p>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139410646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-07DOI: 10.1007/s10694-023-01518-0
Abstract
This paper deals with the fire reaction as well as the gas and aerosol production of Cross-Laminated Timber (CLT) submitted to fire in oxygen-depleted environments. A Controlled-Atmosphere Cone Calorimeter (CACC) coupled to a Fourier Transform Infrared (FTIR) spectroscopy and an Electrical Low Pressure Impactor (ELPI) was used for this purpose. This combination enabled simultaneous assessments of Mass Loss Rate (MLR), evolved gases (qualitatively and quantitatively) and aerosols (size distribution and concentration) in the smoke. Several oxygen levels (21, 18, 15 and 10% O2) were studied at an external heat flux of 50 and 20 kW/m2. The combination of these two parameters allowed the response of CLT to be classified according to different fire scenarios. Indeed, an oxygen decrease shifted the combustion towards incompleteness or even prevented combustion. The production of carbon monoxide and methane was significantly promoted as well as acetaldehyde and ethene in some cases. The aerosol size distribution was slightly affected by oxygen depletion. Furthermore, decreasing the heat flux greatly reduced the decomposition rate but also promoted the production of unburnt gases.
{"title":"Effects of Oxygen Concentration on the Reaction to Fire of Cross-Laminated Timber in a Controlled-Atmosphere Cone Calorimeter","authors":"","doi":"10.1007/s10694-023-01518-0","DOIUrl":"https://doi.org/10.1007/s10694-023-01518-0","url":null,"abstract":"<h3>Abstract</h3> <p>This paper deals with the fire reaction as well as the gas and aerosol production of Cross-Laminated Timber (CLT) submitted to fire in oxygen-depleted environments. A Controlled-Atmosphere Cone Calorimeter (CACC) coupled to a Fourier Transform Infrared (FTIR) spectroscopy and an Electrical Low Pressure Impactor (ELPI) was used for this purpose. This combination enabled simultaneous assessments of Mass Loss Rate (MLR), evolved gases (qualitatively and quantitatively) and aerosols (size distribution and concentration) in the smoke. Several oxygen levels (21, 18, 15 and 10% O<sub>2</sub>) were studied at an external heat flux of 50 and 20 kW/m<sup>2</sup>. The combination of these two parameters allowed the response of CLT to be classified according to different fire scenarios. Indeed, an oxygen decrease shifted the combustion towards incompleteness or even prevented combustion. The production of carbon monoxide and methane was significantly promoted as well as acetaldehyde and ethene in some cases. The aerosol size distribution was slightly affected by oxygen depletion. Furthermore, decreasing the heat flux greatly reduced the decomposition rate but also promoted the production of unburnt gases.</p>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139376473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.1007/s10694-023-01519-z
Timo Jokinen, Risto Ranua, Mikko Salminen
This paper presents the performance-based fire safety analysis of steel structures of padel-center built in Nokia, Finland. The analyses are conducted using advanced calculation models (fire simulations using Fire Dynamics Simulator, FDS, and finite element method, FEM, based analyses of the steel frames in elevated temperatures using SAFIR software, including joint analysis) in support with less sophisticated models (critical temperatures of steel members). The following localized fire scenarios are studied: lounge area furniture fire (4 sofas), sporting equipment fire (10 sporting bags filled with flammable clothing), fire during maintenance (scissor lift fire with miscellaneous temporary fire load) and a fire on HVAC balcony near the trusses. The aim of the paper is showcase recent developments in design processes and methods that are in practical use today in performance-based fire design (PBD), to demonstrate that relatively extensive performance-based studies can be (commercially) viable also in relatively small and mundane steel buildings, and to present a fairly robust framework for PBD of similar steel structures. As a result of the performance-based design, most of the steel structures in the case building could be constructed without fire protection, but some critical structures were identified and protected to class R30. The proposed design was approved by the local municipal authorities.
{"title":"Holistic Performance-Based Fire Design of Steel Structures—Case Study: Sports Hall","authors":"Timo Jokinen, Risto Ranua, Mikko Salminen","doi":"10.1007/s10694-023-01519-z","DOIUrl":"https://doi.org/10.1007/s10694-023-01519-z","url":null,"abstract":"<p>This paper presents the performance-based fire safety analysis of steel structures of padel-center built in Nokia, Finland. The analyses are conducted using advanced calculation models (fire simulations using Fire Dynamics Simulator, FDS, and finite element method, FEM, based analyses of the steel frames in elevated temperatures using SAFIR software, including joint analysis) in support with less sophisticated models (critical temperatures of steel members). The following localized fire scenarios are studied: lounge area furniture fire (4 sofas), sporting equipment fire (10 sporting bags filled with flammable clothing), fire during maintenance (scissor lift fire with miscellaneous temporary fire load) and a fire on HVAC balcony near the trusses. The aim of the paper is showcase recent developments in design processes and methods that are in practical use today in performance-based fire design (PBD), to demonstrate that relatively extensive performance-based studies can be (commercially) viable also in relatively small and mundane steel buildings, and to present a fairly robust framework for PBD of similar steel structures. As a result of the performance-based design, most of the steel structures in the case building could be constructed without fire protection, but some critical structures were identified and protected to class R30. The proposed design was approved by the local municipal authorities.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139373236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.1007/s10694-023-01529-x
Abstract
The patch-loading resistance behaviors of Q690 high-strength steel (HSS) plate girders at elevated temperatures were investigated through a parametric study. The finite element (FE) simulation method was validated with 35 experimental results from the literature. The effects of elevated temperature, web width–height ratio, loading length, and web slenderness were investigated, where 512 FE models were included. A clear reduction in ultimate strength caused by the reduction in mechanical properties was observed with increasing temperature. The effect of elevated temperatures on the stress distribution on the web was negligible. The validation of design procedures in EN 1993-1-5 and AISC 360-16 was conducted, where the elevated temperature material properties of Q690 HSS were used. The results indicated that the current specifications were overly conservative to be used directly to predict the ultimate strength of the Q690 HSS plate girder at elevated temperatures. Accordingly, a design method based on EN 1993-1-5 was proposed. The formula in EN 1993-1-5 for determining the critical buckling factor was modified by introducing an amplification factor. The strength reduction function in EN 1993-1-5 was adjusted using the modified critical buckling factor. To determine the optimal undetermined constants in the strength reduction function, statistical calibration involving 400 combinations of 2 undetermined constants was performed for each pre-determined temperature. Two formulas with temperature as a variable were proposed to determine these undetermined constants directly. Based on the comparison, the accuracy of the proposed design method was better than those of the design methods in EN 1993-1-5 and AISC 360-16.
摘要 通过参数研究,探讨了 Q690 高强度钢 (HSS) 板梁在高温下的贴片加载阻力行为。有限元(FE)模拟方法与文献中的 35 项实验结果进行了验证。研究了高温、腹板宽高比、加载长度和腹板细长度的影响,其中包括 512 个有限元模型。随着温度的升高,力学性能下降导致极限强度明显降低。温度升高对腹板应力分布的影响可以忽略不计。对 EN 1993-1-5 和 AISC 360-16 中的设计程序进行了验证,其中使用了 Q690 高速钢的高温材料特性。结果表明,直接使用现行规范预测 Q690 高速钢板梁在高温下的极限强度过于保守。因此,提出了基于 EN 1993-1-5 的设计方法。EN 1993-1-5 中用于确定临界屈曲系数的公式通过引入放大系数进行了修改。使用修改后的临界屈曲系数对 EN 1993-1-5 中的强度降低函数进行了调整。为确定强度降低函数中的最佳未定常数,对每个预定温度进行了统计校准,涉及 2 个未定常数的 400 种组合。提出了两个以温度为变量的公式来直接确定这些未定常数。根据比较,拟议设计方法的准确性优于 EN 1993-1-5 和 AISC 360-16 中的设计方法。
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Pub Date : 2024-01-03DOI: 10.1007/s10694-023-01527-z
Abstract
Global fire performance of structures in fire is proven to be more advantageous in many cases of engineering practice than the prescriptive fire resistance based on isolated structural member testing. Hybrid fire simulation (HFS) is a novel well-suited method trending in recent years for analysis of global performance of structures in fire. In the principles of this method, the part of a structure which has unknown behavior or is uncertain to be numerically modeled (subjected to fire) would be physically tested, while the rest of the structure is numerically simulated. HFS method enables capturing the beneficial interaction mechanisms evolving between fire-exposed structural members and the adjacent cooler substructure. Due to the continuous temperature increase in a fire test and the existing thermal inertia as well as the rate- and temperature-dependent material behavior of structures exposed to fire, a real-time performance in hybrid fire simulation counts as a necessity. This challenge is more critical for hybrid fire simulations with higher applied heating rates relevant to structural fire engineering. Within scope of this paper, (a) a robust and rigorous approach for real-time HFS is presented; (b) a series of proof-of-concept studies of different hybrid fire simulations with various applied heating rates are carried out for a thermomechanical benchmark problem; (c) the important results of four representative hybrid fire simulations with relevant heating rates to structural fire engineering are discussed; (d) the importance of an appropriate calculation method for stiffness update of the fire-exposed structural member over HFS procedure is highlighted, and e) the precision and accuracy of the applied HFS approach with respect to interface error and real-time degree are evidenced.
{"title":"The Impact of Various Heating Rates on Real-Time Degree of Hybrid Fire Simulation","authors":"","doi":"10.1007/s10694-023-01527-z","DOIUrl":"https://doi.org/10.1007/s10694-023-01527-z","url":null,"abstract":"<h3>Abstract</h3> <p>Global fire performance of structures in fire is proven to be more advantageous in many cases of engineering practice than the prescriptive fire resistance based on isolated structural member testing. Hybrid fire simulation (HFS) is a novel well-suited method trending in recent years for analysis of global performance of structures in fire. In the principles of this method, the part of a structure which has unknown behavior or is uncertain to be numerically modeled (subjected to fire) would be physically tested, while the rest of the structure is numerically simulated. HFS method enables capturing the beneficial interaction mechanisms evolving between fire-exposed structural members and the adjacent cooler substructure. Due to the continuous temperature increase in a fire test and the existing thermal inertia as well as the rate- and temperature-dependent material behavior of structures exposed to fire, a real-time performance in hybrid fire simulation counts as a necessity. This challenge is more critical for hybrid fire simulations with higher applied heating rates relevant to structural fire engineering. Within scope of this paper, (a) a robust and rigorous approach for real-time HFS is presented; (b) a series of proof-of-concept studies of different hybrid fire simulations with various applied heating rates are carried out for a thermomechanical benchmark problem; (c) the important results of four representative hybrid fire simulations with relevant heating rates to structural fire engineering are discussed; (d) the importance of an appropriate calculation method for stiffness update of the fire-exposed structural member over HFS procedure is highlighted, and e) the precision and accuracy of the applied HFS approach with respect to interface error and real-time degree are evidenced.</p>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139094118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}