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See detailFire Performance of undamaged and pre-damaged welded steel-concrete composite beam-to-column joints with concrete filled tubes
Alderighi, Elisabetta; Bursi, Oreste; Franssen, Jean-Marc ULiege et al

Conference (2008, October)

Major earthquakes in urban areas have often been followed by significant conflagrations that have been difficult to control and have resulted in extensive damage to property. Earthquakes, then, increase ... [more ▼]

Major earthquakes in urban areas have often been followed by significant conflagrations that have been difficult to control and have resulted in extensive damage to property. Earthquakes, then, increase the risk of loss of life if a fire occurs within a building. It is obvious therefore that a fire after an earthquake is a design scenario that should be properly addressed in any performance-based design, in locations where significant earthquakes can occur. In this paper both experimental and numerical results of undamaged and pre-damaged welded steel-concrete composite beam-to-column joints with concrete filled tubes are described as part of a European project aimed at developing fundamental data, design guidelines and prequalification of ductile and fire resistant composite beam-to-column joints. In detail, both the experimental program and the fire experimental results are presented and discussed in this paper together with thermal numerical simulations on frames and joints. Both the experimental activity and the numerical work demonstrated the adequacy of the seismic and joint fire design. [less ▲]

Detailed reference viewed: 72 (2 ULiège)
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See detailFire promotes downy brome (Bromus tectorum L.) seed dispersal
Monty, Arnaud ULiege; Brown, Cynthia S.; Johnston, Danielle B.

in Biological Invasions (2013), 15(5), 1113-1123

Particularly well-known among the many impacts of the invasive annual grass downy brome (Bromus tectorum, Poaceae) is its ability to alter fire cycles and increase in abundance after fire. However, little ... [more ▼]

Particularly well-known among the many impacts of the invasive annual grass downy brome (Bromus tectorum, Poaceae) is its ability to alter fire cycles and increase in abundance after fire. However, little is known about how fire influences B. tectorum dispersal. We quantified fire effects on B. tectorum dispersal using three recently burned areas in the western region of the Colorado Rocky Mountains by marking diaspores (seeds) with fluorescent powder, and then recovering them at night using ultraviolet lights. Diaspores were of two types: with and without sterile florets attached. We also characterized vegetation cover and near-surface wind speed in burned and unburned areas. Diaspores travelled much farther in burned areas than in nearby unburned areas (mean ± standard error at the end of the experiment: 209 ± 16 cm and 38 ± 1 cm, respectively; maximal distance at the end of the experiment: 2,274 cm and 150 cm, respectively), indicating an increase in dispersal distance after fire. Diaspores with sterile florets attached dispersed longer distances than those without sterile florets (mean ± standard error at the end of the experiment: 141 ± 14 cm and 88 ± 7 cm, respectively). Vegetation cover was lower and wind speeds were higher in the burned areas. Our results indicate that at least one of the mechanisms by which the spread of B. tectorum is promoted by fire is through increased seed dispersal distance. Preventing movement of seeds from nearby infestations into burned areas may help avoid the rapid population expansion often observed. [less ▲]

Detailed reference viewed: 61 (4 ULiège)
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See detailFire promotes downy brome (Bromus tectorum L.) seed dispersal
Monty, Arnaud ULiege; Brown, Cynthia; Johnston, Danielle

Poster (2012)

Particularly well-known among the many impacts of the invasive annual grass downy brome (Bromus tectorum, Poaceae) is its ability to alter fire cycles and increase in abundance after fire. However, little ... [more ▼]

Particularly well-known among the many impacts of the invasive annual grass downy brome (Bromus tectorum, Poaceae) is its ability to alter fire cycles and increase in abundance after fire. However, little is known about how fire influences B. tectorum dispersal. We quantified fire effects on B. tectorum dispersal using three recently burned areas in the western region of the Colorado Rocky Mountains by marking diaspores (seeds) with fluorescent powder, and then recovering them at night using ultraviolet lights. Diaspores were of two types: with and without sterile florets attached. We also characterized vegetation cover and near-surface wind speed in burned and unburned areas. Diaspores travelled much farther in burned areas than in nearby unburned areas (means ± standard error at the end of the experiment: 209 ± 16 cm and 38 ± 1 cm, respectively; maximal distance at the end of the experiment: 2274 cm and 150 cm, respectively), indicating an increase in dispersal distance after fire. Diaspores with sterile florets attached dispersed longer distances than those without sterile florets (means ± standard error at the end of the experiment: 141 ± 14 cm and 88 ± 7 cm, respectively). Vegetation cover was lower and wind speeds were higher in the burned areas. Our results indicate that at least one of the mechanisms by which the spread of B. tectorum is promoted by fire is through increased seed dispersal distance. Preventing movement of seeds from nearby infestations into burned areas may help avoid the rapid population expansion often observed. [less ▲]

Detailed reference viewed: 113 (4 ULiège)
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See detailFire resistance of a steel structure subjected to a localised fire
Franssen, Jean-Marc ULiege; alonso, Alain

Report (2009)

The fire resistance of a light weight steel structure is analised under a localised fire.

Detailed reference viewed: 33 (0 ULiège)
Peer Reviewed
See detailFire resistance of axially restrained and partially unprotected Ultra Shallow Floor Beams (USFB®) and DELTABEAM® composite beams
Maraveas, Chrysanthos ULiege; Fasoulakis, Zacharias; Tsavdaridis, Konstantinos

in Applications of Structural Fire Engineering (2017)

Ultra-shallow floor types such as the USFB® and DELTABEAM® beam ‘plug’ composite flooring systems are recently developed and have seen many applications in contemporary construction. They involve ... [more ▼]

Ultra-shallow floor types such as the USFB® and DELTABEAM® beam ‘plug’ composite flooring systems are recently developed and have seen many applications in contemporary construction. They involve partially encased steel beams in concrete, with the lower flange remaining exposed. Besides the satisfactory behavior of the system at ambient conditions, understanding their response to elevated temperatures is critical in evaluating their overall performance. Previous numerical studies of the authors have investigated their fire resistance when simply supported. The computational analyses demonstrated that such flooring systems are experiencing severe thermal gradients and bowing. When such beams are axially restrained, the compression due to the restraining may produce second order effects on the bowed beams. On the other hand, the effect of axial restraints is difficult to be estimated because of the temperature’s non-uniformity across the cross-sections. For this reason, comprehensive finite element analyses (FEA) were implemented in this paper to simulate the response of such restrained beams subjected to fire. Material properties were modelled according to Eurocodes. The coupled thermal-structural parametric analyses involved different variations of the “shortest” cross-sections. From the FE analyses, useful conclusions are drawn. [less ▲]

Detailed reference viewed: 36 (1 ULiège)
Peer Reviewed
See detailFire resistance of circular concrete columns
Dotreppe, Jean-Claude ULiege; Bisschops, P.-F.; Franssen, Jean-Marc ULiege

in Proceedings of the 3rd International Conference on Concrete under Sever Conditions (CONSEC'01) (2001)

Detailed reference viewed: 71 (9 ULiège)
Peer Reviewed
See detailFire resistance of columns in steel frames
Franssen, Jean-Marc ULiege; Dotreppe, Jean-Claude ULiege

in Fire Safety Journal (1992), 19(2 - 3), 159-175

The standard fire resistance test is not appropriate for predicting the behaviour of steel frames under fire conditions. The simplified theories that have been published in approved national and ... [more ▼]

The standard fire resistance test is not appropriate for predicting the behaviour of steel frames under fire conditions. The simplified theories that have been published in approved national and international documents apply to some restricted particular cases of single elements (beams, columns). In most practical circumstances beams and columns are subjected to a combination of axial forces and bending moments and have variable restraint and displacement conditions at their ends. The problem is particularly complicated for columns. For this type of situation advanced computer programs can at the present time provide a satisfactory method for the determination of the fire resistance. This paper illustrates the preceding comments by evaluating the fire endurance of an unbraced steel frame with two loading conditions. [less ▲]

Detailed reference viewed: 45 (4 ULiège)
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See detailFire resistance of concrete slabs acting in compressive membrane action
Molkens, Tom; Gernay, Thomas ULiege; Caspeele, Robby

in Nigro, Emidio; Bilotta, Antonio (Eds.) Proceedings of the 2nd International Fire Safety Symposium - IFireSS 2017 (2017, June 08)

In building renovation, the real behaviour of reinforced concrete slabs cannot always be explained by the bending theory according to classical structural mechanics. Indeed, the bearing capacity, as ... [more ▼]

In building renovation, the real behaviour of reinforced concrete slabs cannot always be explained by the bending theory according to classical structural mechanics. Indeed, the bearing capacity, as assessed for instance by a loading test, sometimes appears to be much higher than what would be expected. This phenomenon may be caused by the activation of an arch-effect or so-called compressive membrane action (CMA) which can develop even with small vertical deformations. For a slab which is completely restrained, the presence of reinforcement becomes of lesser importance when this phenomenon is activated (except for end fields). Hence, for fire resistance purposes, it can be discussed whether reinforcement and concrete cover has a smaller influence on the bearing capacity for slabs subjected to fire which exhibit a significant concrete compressive membrane behaviour. This paper presents a loading test performed on a real concrete building which highlighted the development of CMA as the load bearing mode. It then proposes a strategy to evaluate the behaviour resulting from the development of CMA in reinforced concrete slabs at ambient and at elevated temperature based on numerical modelling. The numerical analyses are performed with the finite element software SAFIR® using a strip of layered shell elements. A plastic-damage constitutive model with an explicit transient creep formulation is used to capture the concrete behaviour at elevated temperature. [less ▲]

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See detailFire resistance of DELTABEAM® composite beams: a numerical investigation
Maraveas, Chrysanthos ULiege

in Journal of Structural Fire Engineering (2017)

Purpose – The DELTA® beam composite floor system is a recently developed shallow floor type that has seen many applications in contemporary construction. It involves partially encasing DELTA® steel beams ... [more ▼]

Purpose – The DELTA® beam composite floor system is a recently developed shallow floor type that has seen many applications in contemporary construction. It involves partially encasing DELTA® steel beams in concrete, with the lower flange remaining exposed. Besides the satisfactory behavior of the system at ambient conditions, understanding its response under elevated temperatures is critical in evaluating its overall performance. Despite certification from the manufacturing company that the system has adequate fire resistance, its behavior under fire conditions has neither been investigated to depth nor reported in detail. The purpose of this paper is the detailed numerical investigation of their behavior in fire. For this reason, the finite element method was implemented in this paper to simulate the response of such beams subjected to fire. Material properties were modeled according to the Eurocodes. The coupled thermal-structural parametric analyses involved four different variations of the “shortest” and “deepest” cross-section (eight case studies in total) specified by the manufacturing company. Other simulations of these cross-sections, in which either the thermal expansion or the structural load were not taken into account, were carried out for comparison purposes. Design/methodology/approach – The methodology for simulating such systems, which has been successfully implemented and validated against fire test results elsewhere (Maraveas et al., 2012) was also followed here. To investigate the statement made by Maraveas et al. (2014) and the equations proposed by Zaharia and Franssen (2012) that the insulation is not so effective for “short” cross-sections, two beams, one with a D20-200 (Deltabeam Technical Manual, 2013) cross-section (shallowest section) and one with a D50-600 (Deltabeam Technical Manual, 2013) cross-section (deepest section), were simulated in this paper for comparison purposes. Additionally, reasonable assumptions were made for the cross-sectional dimensions not specified by the manufacturer (Deltabeam Technical Manual, 2013) and parametric analyses were carried out to investigate their effect on the structural response of the system. Findings – Composite DELTA® beams can achieve fire resistances ranging from 120 to 180 min, depending on the depth and geometry of their cross-section, with deeper sections displaying a better fire response. The intense thermal bowing that occurs when these beams are heated from below has a more pronounced effect, in terms of thermally induced deflections for deeper sections. The satisfactory fire resistance of these beams is achieved due to the action of the concrete encased web and the reinforcement which compensate for the loss of the exposed lower flange. Increasing the thickness of the web in deeper sections improves their fire rating up to 180 min. The thickness of the lower flange affects the fire rating of the beams only in a minor way. Practical/implications – The paper describes a numerical methodology to estimate the fire resistance of complex flooring systems. [less ▲]

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See detailFire resistance of long span cellular beam made of rolled profiles
Vassart, Olivier; Hawes, Mike; Simms, Ian et al

Report (2011)

The aim of this document is to describe the calculation methods developed to assess the resistance of simply supported cellular beams in fire conditions. This development has been made in the scope of the ... [more ▼]

The aim of this document is to describe the calculation methods developed to assess the resistance of simply supported cellular beams in fire conditions. This development has been made in the scope of the RFCS FiCEB+ [23] and in the scope of the PHD of O.Vassart [24]. This calculation procedure has been introduced in the ACB+ software available on www.arcelormittal.com/sections [23] RFS2-CT-2007-00042 : FICEB+ - Fire resistance of long span cellular beam made of rolled profiles ; March 2011 [24] O. Vassart, Analytical model for cellular beams made of hot rolled sections in case of fire, PhD Thesis, Université Blaise Pascal Clermont-Ferrand II, 2009 [less ▲]

Detailed reference viewed: 170 (1 ULiège)
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See detailFire resistance of long span cellular beam made of rolled profiles (FICEB) report: Ulster test numerical simulation
Gernay, Thomas ULiege; Franssen, Jean-Marc ULiege

Report (2009)

In the Ulster fire test, a large scale composite floor using cellular beams connected to composite slabs will be tested under natural fire. The particularity of the composite floor in this test is that ... [more ▼]

In the Ulster fire test, a large scale composite floor using cellular beams connected to composite slabs will be tested under natural fire. The particularity of the composite floor in this test is that certain cellular beams will be without any fire protection in order to investigate the contribution of membrane effect to overall fire resistance. However, cellular beams could behave in a very different way compared to traditional steel beams because of risk of local phenomenon. The aim of this study was to build a complex FE Model of whole composite floor system with long span cellular beams connected to composite slab in order to take account of 3D membrane effect. This permitted, on the one hand, to find out the right numerical model for this type of composite floor, and on the other hand to define the appropriate structure to be used for the full scale fire test. In order to achieve this latter purpose, a sensitivity study has be carried out in which determinant parameters for ensuring a good membrane effect have been investigated. [less ▲]

Detailed reference viewed: 166 (14 ULiège)
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See detailFire Resistance of Reinforced Concrete Columns Subjected to Standard Fire – Comparison of an Advanced and a Simplified Method
Achenbach, Marcus; Gernay, Thomas ULiege; Morgenthal, Guido

in Garlock, Maria; Kodur, Venkatesh (Eds.) Structures in Fire (Proceedings of the Ninth International Conference) (2016, June 08)

For designing concrete columns subjected to a standard fire exposure, the Eurocode permits the use of simplified or advanced calculation methods. For the designer, the question of the respective ... [more ▼]

For designing concrete columns subjected to a standard fire exposure, the Eurocode permits the use of simplified or advanced calculation methods. For the designer, the question of the respective advantages of these two types of methods arises. Which situations demand the use of an advanced method? When does a simple method provide sufficient accuracy? In this paper, laboratory tests are recalculated using Finite Element Modeling (FEM) as an advanced and Extended Zone Model (EZM) as a simple method in order to investigate these questions. The recalculations indicate that the simple EZM is of sufficient accuracy for symmetric heated columns without restraints. In contrast, the mechanical behavior of columns heated on three sides demands an advanced method such as FEM to be properly described. [less ▲]

Detailed reference viewed: 57 (7 ULiège)
See detailFire resistance of restrained columns
Franssen, Jean-Marc ULiege

Scientific conference (1998, March 18)

Detailed reference viewed: 12 (1 ULiège)
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See detailFire resistance of simple frames according to eurocode 3
Franssen, Jean-Marc ULiege; schröder, L.; Dotreppe, Jean-Claude ULiege

in Batista, C.; de M Batista, Eduardo; Pfeil, Michèle S. (Eds.) Proc. 5th Int. Colloquium on Structural Stability (1996)

Detailed reference viewed: 41 (2 ULiège)
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See detailFire resistance of timbers from tropical countries and comparison of experimental charring rates with various models
Njankouo, Jacques Michel; Dotreppe, Jean-Claude ULiege; Franssen, Jean-Marc ULiege

in Construction & Building Materials (2005), 19(5), 376-386

Tropical hardwood species are more and more used in the field of construction due to the particular qualities they can offer. Presently it is no longer possible to envisage the development of construction ... [more ▼]

Tropical hardwood species are more and more used in the field of construction due to the particular qualities they can offer. Presently it is no longer possible to envisage the development of construction materials and products without taking into consideration the problem of their fire behaviour, and more particularly of their fire resistance. In the case of timber elements, this characteristic is mainly influenced by the charring rate of the external layers of the element. On the other hand this parameter is influenced by the density of the material. Limited information is available on the charring rate of tropical hardwood species. Therefore experimental investigations have been conducted at the University of Liege to study this characteristic. Seven tropical and three timber species from temperate countries have been examined. Two types of test have been used, one on small specimens, the other on a construction element made of one single material. In the first type, 20 specimens have been manufactured by gluing several laminates together. The specimens were instrumented with four thermocouples inserted at various depths in four different laminates. In the second type, a non-loaded wall made of 12 glued-laminated spruce beam profiles was instrumented with thermocouples embedded at different depths in the panel for the evaluation of the charring rate. Experimental charring rates have been compared with the results derived from Eurocode EC5-1.2 recommendation [ENV 1995-1-2. Eurocode 5: Design of timber structures - Part 1-2: General rules - Structural fire design. European prestandard; 1994], Australian standard AS 1720.4 relation [AS 1720.4. Timber structures Part 4: fire resistance of structural timber members. North Sydney, Australia: Standards Australia; 1990] and White's model [Charring rates of different wood species. PhD dissertation. Madison University of Wisconsin, Madison, WI, 1988; White RH, Erik V, Nordheim EV. Charring rate of wood for ASTM El 19 exposure. Fire Technol 1992-28(1)]. This comparison shows that the results obtained from these three models are not entirely satisfactory for tropical hardwood species. Therefore a new model has been proposed. (C) 2004 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 327 (8 ULiège)
Peer Reviewed
See detailFire resistance of unrestrained welded steel beams submitted to lateral-torsional buckling
Vila Real, P. M. M.; Lopes, N.; Simoes da Silva, L. et al

in Hoffmeister, B.; Hechler, O. (Eds.) Proceedings of the 4th European Conference on Steel and Composite Structures (EUROSTEEL 2005) (2005)

Detailed reference viewed: 29 (1 ULiège)
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See detailFire resistance testing
Dumont, Fabien ULiege

Learning material (2017)

The objective of determining fire resistance is to assess the behaviour of a specimen of a building element when subjected to defined heating, pressure and – if relevant – loading conditions. The ... [more ▼]

The objective of determining fire resistance is to assess the behaviour of a specimen of a building element when subjected to defined heating, pressure and – if relevant – loading conditions. The experimental methods provide a means of quantifying the ability of an element to withstand exposure to such stresses. More precisely, the issue is to quantify the separating and/or loadbearing capacity of a building element in order to ensure the separating function and/or structural stability of a building. A representative sample (called "test specimen") of the building element is exposed to a specified scheme of heating and – where relevant – of loading. The tests are carried out on specimens in full size or on small-scale models for elements exceeding the dimensions of the furnaces. The performances of the test specimen are determined by assessing criteria described in test methods. Fire resistance of the test specimen is expressed as the times for which the appropriate criteria have been satisfied. The times so obtained are a measure of the adequacy of the construction in a fire, but they have no direct relationship with the duration time of a real fire. In Europe, about 50 laboratories currently perform fire resistance tests. [less ▲]

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See detailFire risk assessment of multi-story buildings based on fragility analysis
Gernay, Thomas ULiege; Elhami Khorasani, Negar; Garlock, Maria

in Nigro, Emidio; Bilotta, Antonio (Eds.) Proceedings of the 2nd International Fire Safety Symposium - IFireSS 2017 (2017, June 07)

Recent efforts aim at assessing the fire performance of structures in a probabilistic framework. But there is still no well-established method to quantify the reliability of entire buildings. Previous ... [more ▼]

Recent efforts aim at assessing the fire performance of structures in a probabilistic framework. But there is still no well-established method to quantify the reliability of entire buildings. Previous works focused on isolated structural members, therefore not allowing for a determination of the global safety level of buildings. Here, a new methodology is developed to quantify the reliability of buildings in fire. The methodology uses Monte Carlo simulations for constructing fragility functions associated with different fire breakout locations in a building, then combines the functions to characterize the overall building conditional probability of failure, and finally incorporates the probabilistic models for intensity measure and fire occurrence likelihood. The methodology is applied to multi-story steel buildings. This work addresses fire reliability at the building scale, and therefore is useful for standardizing safety level as well as for evaluating community resilience. [less ▲]

Detailed reference viewed: 124 (10 ULiège)