Measurement of the Behavior of Steel Beams under Localized Fire Exposure

A total of nine localized fire tests on steel beams were designed and conducted in the National Fire Research Laboratory as part of its commissioning project, including thermal tests (Tests 1 through 5) and four-point bending test at ambient (Test 6) and elevated temperatures (Tests 7 through 9). All the tested specimens were nominally 6.2-m long W16×26 beams made of ASTM A992 steel. Each specimen was supported by one of the two following connections: (i) simple support (Tests 1 through 8), and (ii) double-angles bolted to laterally braced support columns (Test 9). The midspan of each specimen was exposed to an open-flame fire using the 1-m2 natural gas burners. The burner 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 data included temperatures, the heat release rates from the burner, and structural measurements including forces, displacements and strains. The Type B standard uncertainties in various measurements were also included. Overall, the test results showed that the heating rate of the specimen was sensitive to the prescribed heat release rate-time relationship. However, the thermal gradient developed in the fire-exposed cross sections of the beam never achieved linearity under the localized fire exposure. Regardless of the connection types and fire conditions (i.e., steady-state or transient-state fire), the beams exhibited a similar behavior and failure mode. When subjected to combined fire and flexural loads, the beam specimens exhibited the lateral-torsional buckling followed by runaway vertical displacements at midspan. Additional details of experimental procedures and uncertainty analysis for this experimental series are provided in the following publications: 1) Zhang, C., Choe, L., Gross, J., Ramesh, S., Bundy, M. (2017). Engineering Approach for Designing a Thermal Test of Real-scale Steel Beam Exposed to Localized Fire. Fire Technology, Vol 53, Issue 4, pp 1535-1554. DOI: 10.1007/s10694-016-0646-7 2) Choe, L., Ramesh, S., Zhang, C., Gross, J. (2016). The Performance of Structural Steel Beams Subjected to a Localized Fire. The 9th International Conference on Structures in Fire (SiF 16), June 8-10, 2016, Princeton, NJ.

                                            [
  "006:55"
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                                            {
  "fn": "Lisa Choe",
  "hasEmail": "mailto:lisa.choe@nist.gov"
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                                            [
  "steel beam; localized fire; thermal and mechanical behavior; experimental test"
]
                                        

                                            [
  "en"
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                                            {
  "name": "National Institute of Standards and Technology",
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                                            [
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                                            [
  "Fire:Structural fire resistance"
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