fire

Hamdallah Bearat's picture

Analyses minéralogiques sur les peintures altérées de la villa gallo-romaine de Vallon

Journal Title, Volume, Page: 
Revue d'Archéométrie 17, 65-74.
Year of Publication: 
1993
Authors: 
Béarat H
Current Affiliation: 
Department of Materials Science, Faculty of Engineering and Information Technology, An-Najah National University, Nablus. Palestine
Preferred Abstract (Original): 

The identified pigments in Vallon roman wall painting are : egyptian blue, calcite, goethite, haematite, green earth (céladonite or glauconite) and soot or charcoal. Owing to the fire, these paintings suffered considerable damages : cracking and weakening of the plaster and of the paints and change of some colours. We observe the transition from white to grey, from yellow to red ; from red to a more or less yellowish brown or to black ; from green to grey, to red or to brown and the disappereance of the black paint. After burial in a clayey and wet soil, these paints show different types of alteration : a calcareous patina and a lot of black spots associated with different colours. These spots were found to be iron and manganese oxides, probably produced by bacterial activity. A preliminary chemical test carried out on some treated paint fragments has shown the presence of some traces of the used chemical products.

Mahmud's picture

Predicting the Demand and Plastic Capacity of Axially Loaded Steel Beam–Columns with Thermal Gradients

Journal Title, Volume, Page: 
Engineering Structures Volume 58, January 2014, Pages 49–62
Year of Publication: 
2014
Authors: 
S.E. Quiel
Dept. of Civil and Env. Engineering, Lehigh University, Bethlehem, PA 18015, USA
M.E.M. Garlock
Dept. of Civil and Env. Engineering, Princeton University, Princeton, NJ 08544, USA
M.M.S. Dwaikat
Dept. of Civil Engineering, An-Najah National University, Nablus, Palestine
Current Affiliation: 
Department of Civil Engineering, Faculty of Engineering and Information Technology, An-Najah National University, Nablus. Palestine
V.K.R. Kodur
Dept. of Civil and Env. Engineering, Michigan State University, East Lansing, MI 48824-1226, USA
Preferred Abstract (Original): 

This study evaluates the adequacy of different methodologies to predict the plastic capacity and response caused by non-uniform thermal gradients through the depth of beam–columns that are loaded only axially at the centroid. Three models with different levels of complexity were used to evaluate the fire response of beam–columns under non-uniform temperature gradients: (1) code-based equations; (2) a fiber-beam element model; and (3) a shell element model that discretizes the full cross section and length and is capable of capturing local (i.e. plate) instability. The code-based equations do not predict the response satisfactorily since these equations do not properly consider temperature gradients. The fiber-beam element and shell model results correlate well to the thermal and structural response of the beam–columns tested experimentally with varying parameters. If local buckling is not expected at ambient temperature, complex shell elements are not necessary when the failure mode is fully plastic and fiber-beam elements, which are simpler and less “computationally expensive” than shells, suffice. The experiments and models also validated equations that consider thermal gradients and predict the plastic capacity and structural response of these members, which includes a moment reversal due to a shift in the section center of stiffness with increasing temperatures.

Mahmud's picture

Strength Design Criteria for Steel Beam-Columns with Fire Induced Thermal Gradients

Journal Title, Volume, Page: 
Engineering Journal, AISC
Year of Publication: 
2011
Authors: 
M.M.S. Dwaikat
Civil and Environmental Engineering Department, Michigan State University, East Lansing
Current Affiliation: 
Department of Civil Engineering, An-Najah National University, Palestine
VKR Kodur
Civil and Environmental Engineering Department, Michigan State University, East Lansing
Preferred Abstract (Original): 
When exposed to fire, restrained steel members develop significant internal forces, and these forces transform their behavior from beams or columns to that of beam-columns. The current provisions for fire-resistance assessment of such beam-columns through P-M interaction equations are an extension to the ambient interaction equations. These fire design equations take into consideration the reduction in the capacity arising from temperature-induced degradation of strength and stiffness properties but do not take into account the effect of other critical factors, such as thermal gradient, end restraints and realistic fire scenarios (with cooling phase). In this study, the different fire design equations for steel beam-columns are compared against results from nonlinear finite element simulations. Results from the analysis show that fire-induced thermal gradient leads to not only a reduction in the P-M diagrams, but also a noticeable distortion in the shape of the P-M diagrams. Therefore, modifications are proposed to the current design interaction equations for steel beam-columns at elevated temperatures. The modified P-M design equations are validated against results from fire tests and from finite element analysis and then illustrated through a design example. The proposed approach requires minimum computational effort and provides better assessment of beam-columns under fire when compared to current provisions.
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