Experiments and Modeling of Structural Steel Elements Exposed to Fire. Federal Building and Fire Safety Investigation of the World Trade Center Disaster.
Experiments and Modeling of Structural Steel Elements Exposed to Fire. Federal Building and Fire
Safety Investigation of the World Trade Center Disaster.
(19804 K)
Hamins, A.; Maranghides, A.; McGrattan, K. B.; Johnsson,
E. L.; Ohlemiller, T. J.; Donnelly, M. K.; Yang, J. C.;
Mulholland, G. W.; Prasad, K. R.; Kukuck, S. R.;
Anleitner, R. L.; McAllister, T. P.
NIST NCSTAR 1-5B; 352 p. September 2005.
Keywords:
World Trade Center; high rise buildings; building
collapse; disasters; fire safety; fire investigations;
terrorists; terrorism; experiments; steel structures;
fire models; thermal environment; fuel flow; heat
release rate; gas temperature; heat flux; smoke; carbon
monoxide; carbon dioxide; oxygen; velocity; tempeature
measurements; compartment fires; thermal response;
thermocouples
Abstract:
Reconstructing the fires and their impact on structural
components in the World Trade Center (WTC) buildings on
September 11, 2001, requires extensive use of
computational models. For the use of such models to be a
viable investigative tool, it is essential to know the
accuracy with which they capture the physical phenomena
of the fires and the concurrent heat transfer to the
building structure. This report documents a series of
large-scale experiments that was conducted in the
National Institute of Standards and Technology (NIST)
Large Fire Laboratory from March 10 to March 26, 2003.
The experiments represent one phase of an effort to
ascertain the validity of the models for the NIST WTC
Investigation. The objective of the experiments was to
assess the accuracy with which (1) the NIST Fire
Dynamics Simulator (FDS) fire model predicts the thermal
environment in a burning compartment and (2) the NIST
Fire Structure Interface (FSI) model in combination with
the ANSYS finite-element model predicts the temperature
rise of structural steel components in a burning
compartment. The experiments also had the potential to
improve input parameters in the modeling, if
appropriate, and, in general, help to increase
understanding of the sequence of events that occurred in
the WTC tower fires. Within a steel-frame compartment
(3 m by 7 m by 4 m) lined with calcium silicate board
were placed four steel components: two trusses, one
thin-walled column, and a rod. The components either
were uninsulated or had fibrous sprayed fire-resistive
material (SFRM) applied; two thicknesses were tested.
The 2 MW and 3 MW fires were generated using liquid
hydrocarbon fuels introduced by a two-nozzle spray
burner onto a by 2 m pan. The fuels were a commercial
blend of heptane isomers and a mixture of the heptane
blend with toluene. Six experiments were conducted.
