Fire Resistance of Protected Steel Beam Floor and Roof Assemblies as Affected by Structural Restraint

2009 ◽  
pp. 63-63-28 ◽  
Author(s):  
R. W. Bletzacker
Keyword(s):  
Fire Resistance ◽  
Steel Beam

scholarly journals Practical Fire Safety Assessment of Steel-beam Floors Made According to the Old Technologies – an Exemplary Case Study. Influence of the Initial Assumptions on the Final Results of Analyses

2017 ◽  
Author(s):  
Pawel Artur Krol
Keyword(s):  
Fire Resistance ◽  
Structural Design ◽  
Safety Assessment ◽  
Steel Beam ◽  
Practical Applications ◽  
Standard Fire ◽  
The Subject ◽  
Technical Features ◽  
The Eu

The purpose of this article is to present procedures and methodsfor assessing fire resistance of steel-beam floors with thejoists hidden within the thickness of the slab. These technologiesare currently experiencing their renaissance, both in contemporarilydesigned buildings and the existing ones, subjectedto comprehensive redevelopment, refurbishment or modernization.Due to their simplicity and ease of execution, these floorsare just perfect as technology ideal for repairs or alterations ofbuildings under use or in the case of need of complete replacementof existing floors with new ones. These arguments justifythe need to raise the subject of proper safety assessment of thesefloors in relation to the regulations and requirements of lawsapplicable in the EU and pursuant to provisions of the latestcodes for structural design. A significant part of the study consistsof a suggestive computational example, which is a sort ofguide, in which the author, by making detailed step-by-step calculationsproduces a finished pattern of procedure, intended formultiple use. The suggested method of procedure can be successfullyused in the assessment of the fire resistance of floorstructures with similar technical features. The computationalexample presented in the study shows that contrary to a popularbelief, the use of standard fire model does not always leadto conservative estimates. In the article summary, the authorformulates a number of practical applications and conclusions.

scholarly journals Behaviour of restrained steel beam at elevated temperature – parametric studies

2019 ◽  
Vol 10 (3) ◽  
pp. 324-339
Author(s):  
Ahmed Allam ◽  
Ayman Nassif ◽  
Ali Nadjai
Keyword(s):  
Axial Force ◽  
Fire Resistance ◽  
Large Deflection ◽  
Elevated Temperatures ◽  
Load Ratio ◽  
Steel Beam ◽  
Content Type ◽  
Catenary Action ◽  
Depth Ratio ◽  
The Impact

Purpose This paper aims to investigate computationally and analytically how different levels of restraint from surrounding structure, via catenary action in beams, affect the survival of steel framed structures in fire. This study focuses on examining the mid-span deflection and the tensile axial force of a non-composite heated steel beam at large deflection that is induced by the catenary action during exposure to fires. The study also considers the effect of the axial horizontal restraints, load-ratio, beam temperature gradient and the span/depth ratio. It was found that these factors influence the heated steel beam within steel construction and its catenary action at large deflection. The study suggests that this may help the beam to hang to the surrounding cold structure and delay the run-away deflection when the tensile axial force of the beam has been overcome. Design/methodology/approach This paper is part one of the parametric study and discusses both the effect of the axial horizontal restraints and load-ratio on the heated steel-beam. Reliance on the prescriptive standard fire solutions may lead to an unpredicted behaviour of the structure members if the impact of potential real fires is not considered. Findings Variation of the horizontal end-restraint level has a major effect on the behaviour of the beam at high deflection, and the loading on a beam at large displacement can be carried effectively by catenary behaviour. An increase of axial horizontal stiffness helps the catenary action to prevent run-away at lower deflections. The studies also investigated the influence of varying the load ratio on the behaviour of the heated beam at large deflection and how it affects the efficacy of the catenary action. The study suggests that care should be taken when selecting the load ratio to be used in the design. Originality/value In a recent work, the large deflection behaviours of axially restrained corrugated web steel beam (CWSB) at elevated temperatures were investigated using a finite element method (Wang et al., 2014). Parameters that greatly affected behaviours of CWSB at elevated temperatures were the load ratio, the axial restraint stiffness ratio and the span–depth ratio. Other works included numerical studies on large deflection behaviours of restrained castellated steel beams in a fire where the impact of the catenary action is considered (Wang, 2002). The impact of the induced axial forces in the steel beam during cooling stage of a fire when the beam temperature decreases, if thermal shortening of the beam is restrained, large tensile forces may be induced in the beam (Wang, 2005; Allam et al., 2002). A performance-based approach is developed for assessing the fire resistance of restrained beams. The approach is based on equilibrium and compatibility principles, takes into consideration the influence of many factors, including fire scenario, end restraints, thermal gradient, load level and failure criteria, in evaluating fire resistance (Dwaikat and Kodur, 2011; Allam et al., 1998).

Comparison of Simplified and Advanced Design of Steel Structures in Fire

2018 ◽  
Vol 1147 ◽  
pp. 24-29
Author(s):  
Jerneja Kolšek ◽  
Andrej Rebec
Keyword(s):  
Critical Temperature ◽  
Fire Resistance ◽  
Steel Structures ◽  
Steel Beam ◽  
Steel Girder ◽  
Structural Fire ◽  
Simplified Procedures ◽  
Plate Connection ◽  
In Fire ◽  
Structural Fire Resistance

This paper presents the possible deviations between “realistic” (performance-based) calculations of fire resistance of steel structures and corresponding calculations made by one of the often used simplified (prescriptive) procedures of EN 1993-1-2 i.e. the method of critical temperature (MCT). The comparison is done for a case of an assembly consisting of a steel beam and a steel girder connected to each other by a bolted fin-plate connection. For such structure the MCT method suggests that the structural fire resistance is 50 minutes. However, the realistic fire resistance calculated by an advanced performance-based procedure is evaluated to 44 minutes. Although the discrepancy between the results of both methods is not significant in the presented case, this finding implies that MCT can be on the unsafe side for some cases. More future debates and clarifications are therefore encouraged regarding the actual limits of the applicability of the simplified procedures.

Analysis of Mechanics Characteristics of Prestressed Steel Beam in High Temperature (Fire) Condition

2013 ◽  
Vol 351-352 ◽  
pp. 519-523
Author(s):  
Qiang Sun ◽  
Wei Tian ◽  
Ding Tang Wang
Keyword(s):  
High Temperature ◽  
Fire Resistance ◽  
Steel Structures ◽  
Steel Beam ◽  
Science Theory ◽  
Beam Design ◽  
Fire Condition ◽  
Steel Cables ◽  
Control Forces ◽  
Mechanics Characteristics

According to the requirements of fire science theory and structural fire resistance design, and the situation of possible disasters that may occur in the building based on practical project, this paper analyzes the mechanical characteristics of prestressed steel beam under high temperature (fire) circumstances. It puts forward how to consider the effects of parameters of different steel categories, the magnitude of prestress tension control forces and prestressed loss of steel cables on the structural bearing capacity in prestressed steel beam design, which can provide references for the fire resistance design of prestressed steel structures.

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