Fire analysis of steel frames with the use of artificial neural networks

The paper presents an alternative approach to the modelling of the mechanical behaviour of steel frame material when exposed to the high temperatures expected in fires. Based on a series of stress-strain curves obtained experimentally for various temperature levels, an artificial neural network (ANN) is employed in the material modelling of steel. Geometrically and materially, a non-linear analysis of plane frame structures subjected to fire is performed by FEM. The numerical results of a simply supported beam are compared with our measurements, and show a good agreement, although the temperature-displacement curves exhibit rather irregular shapes. It can be concluded that ANN is an efficient tool for modelling the material properties of steel frames in fire engineering design studies. (c) 2007 Elsevier Ltd. All rights reserved

Cluster Lenses

Clusters of galaxies are the most recently assembled, massive, bound structures in the Universe. As predicted by General Relativity, given their masses, clusters strongly deform space-time in their vicinity. Clusters act as some of the most powerful gravitational lenses in the Universe. Light rays traversing through clusters from distant sources are hence deflected, and the resulting images of these distant objects therefore appear distorted and magnified. Lensing by clusters occurs in two regimes, each with unique observational signatures. The strong lensing regime is characterized by effects readily seen by eye, namely, the production of giant arcs, multiple-images, and arclets. The weak lensing regime is characterized by small deformations in the shapes of background galaxies only detectable statistically. Cluster lenses have been exploited successfully to address several important current questions in cosmology: (i) the study of the lens(es) - understanding cluster mass distributions and issues pertaining to cluster formation and evolution, as well as constraining the nature of dark matter; (ii) the study of the lensed objects - probing the properties of the background lensed galaxy population - which is statistically at higher redshifts and of lower intrinsic luminosity thus enabling the probing of galaxy formation at the earliest times right up to the Dark Ages; and (iii) the study of the geometry of the Universe - as the strength of lensing depends on the ratios of angular diameter distances between the lens, source and observer, lens deflections are sensitive to the value of cosmological parameters and offer a powerful geometric tool to probe Dark Energy. In this review, we present the basics of cluster lensing and provide a current status report of the field.Comment: About 120 pages - Published in Open Access at: http://www.springerlink.com/content/j183018170485723/ . arXiv admin note: text overlap with arXiv:astro-ph/0504478 and arXiv:1003.3674 by other author

Analytic equivalents of standard fire temperature curves

A report of the development of analytical expressions that result in an improved fit to the standard time-temperature curve.Dans les \ue9tudes analytiques, on doit remplacer par un expression la courbe de temp\ue9rature du brasier sp\ue9cifi\ue9e dans la norme E-119 de l'ASTM pour les essais d'incendie de b\ue2timents en construction. Le pr\ue9sent article propose quelques expressions acceptables, dont on a calcul\ue9 les constantes par des m\ue9thodes de "moindres carr\ue9s".Peer reviewed: NoNRC publication: Ye

Approximations for spatial separation

Strict application of the theory governing ignition by radiation would demand tedious calculations to determine distances between buildings sufficient to prevent fire spread. The author proposes simple formulae that can be used with relative ease to estimate safe separation distances.Le calcul pr\ue9cis des distances devant s\ue9parer les b\ue2timents en vue de pr\ue9venir la propagation des incendies par la chaleur qu'\ue9met un b\ue2timent en feu est assez laborieux. Le pr\ue9sent expos\ue9 donne des m\ue9thodes de calcul rapide des distances approximatives.Peer reviewed: NoNRC publication: Ye

Effective thermal inertia in relation to normalized heat load

Normalized heat load, obtained by dividing heat absorption by thermal inertia, is a quantity useful in building design for relating fire severity in fully developed compartment fires to fire severity in standard fire resistance tests. Harmathy has shown how normalized heat load may be used for determining required fire resistance in projected buildings. The present work describes how effective values of thermal inertia can be calculated for such important materials as brick and concrete, both normal and lightweight, for which thermal properties depend strongly upon temperature.La charge thermique normalis\ue9e, calcul\ue9e en divisant l'absorption thermique par l'inertie thermique, permet de lier la violence d'un incendie lors de feux de compartiment en vraie grandeur \ue0 la violence d'un incendie mesur\ue9e lors d'essais courants de r\ue9sistance au feu. Harmathy a montr\ue9 comment la charge thermique normalis\ue9e pouvait \ueatre utilis\ue9e pour d\ue9terminer la r\ue9sistance au feu requise dans les b\ue2timents projet\ue9s. Cet article explique comment on peut obtenir des valeurs efficaces de l'inertie thermique pour des mat\ue9riaux tels que la brique et le b\ue9ton, pour lesquels les propri\ue9t\ue9s thermiques d\ue9pendent fortement de la temp\ue9rature.Peer reviewed: YesNRC publication: Ye

Fire Deaths in the Province of Ontario 1958 and 1959

This is the fourth of a series of reports on deaths due to fire in Ontario. It analyses the circumstances surrounding such deaths for the years 1958 and 1959. Since it is proposed to terminate this survey at the end of 1960 this report is less detailed than its predecessors. The final report will contain comparisons between the seven years of the study similar to those in the last report.Peer reviewed: NoNRC publication: Ye

Program to Analyse Results and Prepare Graphs for Fire- Resistance Test Reports

Peer reviewed: NoNRC publication: Ye

Multiple regression analysis of fire deaths from burns

A multiple regression procedure for investigating relation between associated variables is described. Besides statistical criteria, prior knowledge and the simplicity and usefulness of the result are taken into account. The procedure is illustrated by an analysis of survival of burn victims in Ontario.On d\ue9crit une technique de r\ue9gression multiple pour \ue9tudier la relation entre les variables associ\ue9es. En plus des crit\ue8res statistiques, on a tenu compte des connaissances empiriques ainsi que de la simplicit\ue9 et de l'utilit\ue9 des r\ue9sultats. La technique est illustr\ue9e au moyen d'une analyse de la survie des victimes d'incendies en Ontario.Peer reviewed: NoNRC publication: Ye

St. Lawrence Burns: Smoke and Sound Measurements

The circumstances that led to the carrying out of fire tests on eight buildings in the project known as the St. Lawrence Burns, and the objectives and the ways in which these were achieved are fully described in a general report. It constitutes the complete record of the planning and execution of the experiments, together with all general information. The details on each kind of measurement made including the results obtained, are contained in separate companion reports of which this is one. All the results are combined and are discussed and final conclusions drawn in a summary report.Les circonstances ayant men\ue9 \ue0 la r\ue9alisation d?essais de r\ue9action au feu sur huit (8) b\ue2timents, dans le cadre du projet d\ue9sign\ue9 St. Lawrence Burns, ainsi que les objectifs vis\ue9s et les diff\ue9rentes m\ue9thodes employ\ue9es pour r\ue9aliser ces essais font l?objet d?une description exhaustive dans un rapport de type g\ue9n\ue9ral. Il s?agit de la consignation compl\ue8te de la planification et de l?ex\ue9cution des exp\ue9riences men\ue9es, accompagn\ue9e de toute l?information g\ue9n\ue9rale pertinente. Les d\ue9tails de chaque type de mesure r\ue9alis\ue9, y compris les r\ue9sultats obtenus, sont inclus dans des rapports compl\ue9mentaires s\ue9par\ue9s, dont celui-ci. Tous les r\ue9sultats sont collig\ue9s et trait\ue9s, et des conclusions sont tir\ue9es dans un rapport sommaire.Peer reviewed: NoNRC publication: Ye

Another approximation for spatial separation

A simple, accurate and fail-safe method is given for calculating the separations between buildings that would be sufficient to prevent spread of fire by radiation. The new method makes tables unnecessary for this purpose, and avoids the errors of the "gray radiator" method, which are explained. The article is primarily intended to assist those who wish to simplify building codes, but the theoretical basis is also stated.L'article donne une m\ue9thode simple, pr\ue9cise et s\ufbre de calculer l'espacement entre des b\ue2timents suffisant pour pr\ue9 venir la propagation du feu par rayonnement. La nouvelle m\ue9 thode permet de se dispenser des tables et \ue9viter les erreurs de la m\ue9thode dite du "gray radiator". L'article est destin\ue9 principalement \ue0 aider ceux qui d\ue9sirent simplifier les codes de b\ue2timent, mais la base th\ue9orique de la m\ue9thode est aussi expliqu\ue9e.Peer reviewed: NoNRC publication: Ye