000013306 001__ 13306
000013306 005__ 20161114160335.0
000013306 04107 $$aeng
000013306 046__ $$k2009-06-22
000013306 100__ $$aUsmani A., S.
000013306 24500 $$aFire induced progressive collapse of tall buildings

000013306 24630 $$n2.$$pComputational Methods in Structural Dynamics and Earhquake Engineering
000013306 260__ $$bNational Technical University of Athens, 2009
000013306 506__ $$arestricted
000013306 520__ $$2eng$$aThe tragic events of September 11, 2001 that culminated in the total collapse of three very tall buildings in the space of a few hours, left many unanswered questions for structural engineers in their wake. The recently concluded investigations by NIST[1] have partially addressed some these questions but have also raised many new ones. A much smaller scale parallel investigation has also been carried out at the University of Edinburgh [2, 3] primarily to answer specific questions about the role that fire may have played in the collapse of these buildings. In the course of this primarily computational work progressive collapse mechanisms have been discovered whereby tall buildings may suffer progressive or disproportionate collapse because of the effect of fire in single or multiple floors. This paper will explain these mechanisms which have identical antecedents but result in different final outcomes, described formally here as a weak-floor collapse mechanism or a strong-floor collapse mechanism. A structural frame with a weak floor system is shown to fail progressively in a buckling mode, whereas frames with stronger floor systems fail by forming hinges in the perimeter column. This produces interesting analogies with earthquake engineering design in terms of the weak-beam strong-column concept, which will be explored in the paper. The conditions under which these collapse mechanisms may occur in general frame structures will be discussed and simplified analysis methods will be presented in order to identify the risk of such a collapse in existing or future tall buildings.

000013306 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000013306 653__ $$aStructures in fire, progressive collapse, tall buildings, structural fire design. Abstract. The tragic events of September 11, 2001 that culminated in the total collapse of three very tall buildings in the space of a few hours, left many unanswered questions for structural engineers in their wake. The recently concluded investigations by NIST[1] have partially addressed some these questions but have also raised many new ones. A much smaller scale parallel investigation has also been carried out at the University of Edinburgh [2, 3] primarily to answer specific questions about the role that fire may have played in the collapse of these buildings. In the course of this primarily computational work progressive collapse mechanisms have been discovered whereby tall buildings may suffer progressive or disproportionate collapse because of the effect of fire in single or multiple floors. This paper will explain these mechanisms which have identical antecedents but result in different final outcomes, described formally here as a weak-floor collapse mechanism or a strong-floor collapse mechanism. A structural frame with a weak floor system is shown to fail progressively in a buckling mode, whereas frames with stronger floor systems fail by forming hinges in the perimeter column. This produces interesting analogies with earthquake engineering design in terms of the weak-beam strong-column concept, which will be explored in the paper. The conditions under which these collapse mechanisms may occur in general frame structures will be discussed and simplified analysis methods will be presented in order to identify the risk of such a collapse in existing or future tall buildings.

000013306 7112_ $$aCOMPDYN 2009 - 2nd International Thematic Conference$$cIsland of Rhodes (GR)$$d2009-06-22 / 2009-06-24$$gCOMPDYN2009
000013306 720__ $$aUsmani A., S.
000013306 8560_ $$ffischerc@itam.cas.cz
000013306 8564_ $$s1037599$$uhttps://invenio.itam.cas.cz/record/13306/files/CD452.pdf$$yOriginal version of the author's contribution as presented on CD, section: Progress and challenges in collapse prediction - i (MS).
000013306 962__ $$r13074
000013306 980__ $$aPAPER