Engineering Approach for Designing a Thermal Test of Real-Scale Steel Beam Exposed to Localized Fire

Zhang, Chao; Choe, Lisa; Gross, John L.; Ramesh, Selvarajah; Bundy, Matthew F.

doi:10.1007/s10694-016-0646-7

Cited by 18 publications

(5 citation statements)

References 16 publications

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“…The procedure outlined in Figure 2 was used previously to design the test fire for structural experiments on a 6 m long steel W-shape beam during the commissioning of the NFRL [34]. In this study, only the average gas temperature in the compartment was considered and therefore the heat conduction analyses for the exposed members was not be performed.…”

Section: Design Objective and Proceduresmentioning

confidence: 99%

“…For situations where the effect of fire induced thermal gradient is significant, fire protection design based on the furnace tests might not be conservative [27][28][29][30]. Therefore, testing structures in realistic fires becomes a priority in moving towards structural fire engineering design [31], and the development of novel fire testing methods has become an important research topic [32][33][34]. A notable achievement of realistic fire testing is the construction of a unique facility: the National Fire Research Laboratory (NFRL) at the National Institute of Standards and Technology [35].…”

Section: Introductionmentioning

confidence: 99%

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Design of an ASTM E119 Fire Environment in a Large Compartment

et al. 2019

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Structural fire protection design in the United States is based on prescriptive fire-resistance ratings of individual load-bearing elements which are derived from standard fire testing, e.g. ASTM E119. In standard fire testing, a custom-built gas furnace is traditionally used to heat a test specimen by following the gas temperature-time curve prescribed in the ASTM E119 standard. The span length of the test specimen seldom exceeds 6 m due to the size limitations of available furnaces. Further, the test specimen does not incorporate realistic structural continuity. This paper presents a basis for designing an ASTM E119 fire environment in a large compartment of about 10 m wide, 7 m deep and 3.8 m high constructed in the National Fire Research Laboratory of the National Institute of Standards and Technology. Using the designed fire parameters, a full-scale experiment was carried out on December 20, 2018. The measured average upper layer gas temperature curve was consistent with the E119 fire curve. The maximum difference between the measured curve and the E119 fire curve towards the end of the test was about 70 °C (7%). The study indicates that by proper design and control, the time-temperature curve for the standard fire testing may be approximated in a real compartment. The experimental method suggested in this paper would allow to extend the application of the standard fire testing to large-scale structures not limited by the size of furnaces, to experimentally evaluate the thermally-induced failure mechanism of structural systems including connections and frames, and to advance fire protection design methods.

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Section: Design Objective and Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design of an ASTM E119 Fire Environment in a Large Compartment

et al. 2019

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“…Each specimen was supported by steel columns using one of two beam-to-column connection types: (a) a seated connection simulating simply-supported boundary conditions, and (b) a bolted double-angle connection. The data produced from the tests were used for validation of the computational models developed by Zhang et al (2017).…”

Section: Nfrl Commissioning Test Seriesmentioning

confidence: 99%

“…The timedependent function of the burner HRR was designed so that the beam specimen was exposed to a growing fire for about 30 min prior to its failure. It should be noted that the t-squared fire used in the tests were intended for verification of measurement and testing apparatus and for producing the data necessary for validation of computational models developed by Zhang et al (2017). ______________________________________________________________________________________________________ …”

Section: Natural Gas Burner and Fuel Delivery Systemmentioning

confidence: 99%

National fire research laboratory commissioning project: testing steel beams under localized fire exposure

Choe¹,

Ramesh²,

Hoehler³

et al. 2018

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The policy of the National Institute of Standards and Technology is to use metric units in all its published materials. Because this report is intended for the U.S. building construction industry, which uses inch-pound units, it is more practical and less confusing to use inch-pound units, in some cases, rather than metric units. However, in most cases, units are presented in both metric and the inch-pound system. Certain commercial entities, equipment, products, or materials are identified in this document in order to describe a procedure or concept adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities, products, materials, or equipment are necessarily the best available for the purpose.Another policy of the National Institute of Standards and Technology is to include statements of uncertainty with all NIST measurements. In this document, however, some measurements of authors outside of NIST are presented, for which uncertainties were not reported and are unknown. iii National Institute of Standards and Technology ABSTRACTThis report presents the experimental design and results of a series of localized fire tests on structural steel I-shaped beams. A total of nine tests were conducted in the National Fire Research Laboratory, including thermal tests (Tests 1 through 5) and four-point bending tests at ambient (Test 6) and elevated temperatures (Tests 7 through 9). The specimens were nominally 6.2-m long W16×26 beams made of ASTM A992 steel. Each specimen was vertically supported with either a (i) simple support condition, or (ii) double-angles bolted to laterally braced support columns. The thermally-loaded specimens were exposed to fire generated using a natural gas burner. The burner had an area of 1 m 2 and was located 1.1 m below the bottom flange of the beam at midspan. A four-point flexural loading scheme was used to apply concentrated forces at two locations 2.44 m apart around midspan. The recorded data included temperatures, heat release rates from the burner, and structural measurements including forces, displacements and strains. The repeatability of several measurements was evaluated. The test results indicated that the heating rate of the specimen was sensitive to the prescribed heat release rate versus time relationship used in each test. However, the thermal gradient developed in the fire-exposed cross sections of the beam never achieved linearity under the localized fire exposure. When the exposed (bottom) flange temperature was maintained to 616 °C, the load-bearing capacity of the simply-supported beam was reduced to 67 % of its room-temperature capacity. When the same simply-supported beam was initially loaded to 67 % of its room-temperature capacity and then exposed to a growing (t-squared) fire, the exposed flange temperature of the beam at failure was 663 °C. When the beam specimen was supported by double-angle connections and subjected to the same bending mo...

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“…Therefore, a study based on the reproduction of the situation in the same structure as that of the building in which the fire occurred is required to reveal the flame behaviors at the time of the fire more accurately. The data collection methods in this research include a real-scale fire test [10][11][12][13][14][15][16][17], in which the main part or the whole structure where the fire occurred is constructed and a fire is intentionally generated [10][11][12][13][14][15][16], and a fire simulation, in which data are collected by computer simulation of the structure [18][19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Fire Spread of Thermal Insulation Materials in the Ceiling of Piloti-Type Structure: Comparison of Numerical Simulation and Experimental Fire Tests Using Small- and Real-Scale Models

Suh

Park

et al. 2019

Sustainability

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Large-scale fires mainly due to the ignition of thermal insulation materials in the ceiling of piloti-type structures are becoming frequent. However, the fire spread in these cases is not well understood. Herein we performed small-scale and real-scale model tests, and numerical simulations using a fire dynamics simulator (FDS). The experimental and FDS results were compared to elucidate fire spread and effects of thermal insulation materials on it. Comparison of real-scale fire test and FDS results revealed that extruded polystyrene (XPS) thermal insulation material generated additional ignition sources above the ceiling materials upon melting and propagated and sustained the fire. Deformation of these materials during fire test generated gaps, and combustible gases leaked out to cause fire spread. When the ceiling materials collapsed, air flew in through the gaps, leading to flashover that rapidly increased fire intensity and degree of spread. Although the variations of temperatures in real-scale fire test and FDS analysis were approximately similar, melting of XPS and generation of ignition sources could not be reproduced using FDS. Thus, artificial settings that increase the size and intensity of ignition sources at the appropriate moment in FDS were needed to achieve results comparable to those recorded by heat detectors in real-scale fire tests.

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Engineering Approach for Designing a Thermal Test of Real-Scale Steel Beam Exposed to Localized Fire

Cited by 18 publications

References 16 publications

Design of an ASTM E119 Fire Environment in a Large Compartment

Design of an ASTM E119 Fire Environment in a Large Compartment

National fire research laboratory commissioning project: testing steel beams under localized fire exposure

Fire Spread of Thermal Insulation Materials in the Ceiling of Piloti-Type Structure: Comparison of Numerical Simulation and Experimental Fire Tests Using Small- and Real-Scale Models

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