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Research Data Base (RDB)

RDB Record ID: 7975, completed (01.01.2002 - 30.06.2007), last update: 21.12.2007

 

Project leader: Fontana, Mario, D-BAUG, IBK

ETH researcher: Knobloch, Markus

Funding sources: Others

 

Short Summary: It is the aim of the ongoing research project to develop a new design method for steel members subjected to fire, considering transient heating, thermal expansion and internal thermal stresses, local buckling and strain-dependent material behavior at elevated temperatures.

 

Keywords: Engineering Sciences

 

Project description:

During a fire, unprotected thin-walled steel structures heat up quickly because of their high section factors A/V and the good thermal conductivity of steel. Due to the elevated temperatures in fire, the strength and stiffness of steel decreases rapidly and may lead to local buckling.

 

Local buckling and additional capacity resulting from plastic cross sectional behavior have a strong influence on the resistance of steel sections subjected to fire. Due to large strains required because of the distinct nonlinear material behavior of steel at elevated temperatures, local buckling of steel members occurs at lower geometrical slenderness ratios in fire than for room temperature. However, large strains and plastification lead to a distinct increase of cross sectional capacity of thin-walled sections. The research indicates that the design methods for room temperature cannot be adapted by changing the material properties only.

 

The most commonly used design method to calculate fire resistance of steel members considers temperature-dependent material properties but uses the same resistance formulas as for room temperature design. Although the effective yield strength at elevated temperatures is reached for large, nonreversible strains, the cross sections are (as a simplification) often classified as for normal temperature design.

 

It is the aim of the ongoing research project at the ETH Zurich to review this procedure and to develop a new design method for steel members subjected to fire, considering transient heating, thermal expansion and internal thermal stresses, local buckling and strain-dependent material behavior at elevated temperatures. In a first step, the behavior of steel plates supported on three and four sides were studied.

 

A proposal for a structural model for steel plates in bending and compression at elevated temperatures is evolved. A strain-based formulation for effective widths considering plastic stress distribution and strain-dependent nonlinear material behavior is developed to analyze the load-carrying capacity at elevated temperatures of steel plates supported on three or four sides (Fig.1).

 

The proposal is in good agreement with the results found with the finite-element method. Using the program Abaqus, geometrical and physical nonlinear calculations are performed. In a parametric study, the resistance of steel plates supported on three and four sides with variation of the geometrical slenderness and steel temperature are calculated.

 

Publications:

  • Fontana, M., Knobloch, M. 2003. Beulverhalten dünnwandiger Stahlquerschnitte bei Brandeinwirkung. Festschrift zum 60. Geburtstag von Univ.-Prof. Dr.-Ing. Dietmar Hosser, Technische Universität Braunschweig Institut für Baustoffe, Massivbau und Brandschutz, (Heft 173), Braunschweig, 145- 161.
  • Fontana M., Knobloch M. 2004-09-24. Fire resistance of steel columns with partial loss of fire protection. Proceedings, of the IABSE Symposium 2004 - Metropolitan Habitats and Infrastructure, IABSE, (-/ 88), Shanghai, IABSE, 2.
  • Fontana M., Knobloch M. 2004-07-07. Load-carrying behaviour of thin-walled steel sections subjected to fire. Proceedings, Second International Conference on Structural Engineering, Alphose Zingoni, A. A. Balkema Publishers, (-/ -), Cape Town, Taylor & Francis Group plc, London, 6.
  • Fontana M., Knobloch M. 2004-05-11. Local buckling behaviour and strain-based effective widths of steel structures subjected to fire. J.M. Franssen et al. (ed.), SiF’04 Structure in Fire Proceedings of the Third International Workshop, Institute for Research in Construction, (-/ -), Ottawa, 18.
  • Knobloch, M.; Fontana, M. 2007-01-01. Compression strength of stiffened elements in fire. Structural Engineering, Mechanics and Computation, Millpress, Rotterdam, 465-466.
  • Knobloch, Markus. 2007-01-01. Zum Tragverhalten beulgefährdeter Stahlquerschnitte bei Brandeinwirkung. IBK Bericht, vdf Hochschulverlag, (303), Zürich, vdf Hochschulverlag.
  • Knobloch Markus. 2005-06-08. Steel Section subjected to Local Buckling and Fire. Proceedings of the 1st International PhD Workshop on Fire Protection Science and Engineering, Hosser D., TU Braunschweig, Hanover, iBMB and vfdb, 15.
  • Knobloch, Markus; Fontana, Mario. 2007-01-01. Dehnungsabhängige Berechnung vierseitig gelagerter Querschnittselemente unter Druckbeanspruchung im Brandfall. Stahlbau, Ernst & Sohn, Wiley, (8/ 76), Berlin, 521-529.
  • Knobloch, Markus; Fontana, Mario. 2005-01-01. Load-carrying behaviour of unstiffened elements at elevated temperatures in fire. Fire safety science, Hemisphere Publishing, (8), Washington, IAFSS, 223-234.
  • Knobloch, Markus; Fontana, Mario. 2005-01-01. Local buckling behaviour under fire conditions. IABSE reports, IABSE, (90), Zürich, IVBH, 268-269.
  • Knobloch, Markus; Fontana, Mario. 2006-01-01. Strain-based approach to local buckling of steel sections subjected to fire. Journal of constructional steel research, Elsevier, (1-2/ 62), Kidlington, Oxford, 44-67.

RDB Record ID: 9079, completed (11.07.2002 - 31.12.2009), last update: 03.01.2011

 

Project leader: Fontana, Mario, D-BAUG, IBK

ETH researchers: Frangi, Andrea and Schleifer, Vanessa

Funding sources: Public institutions

 

Short Summary: The aim of the research project is to development of a calculation model for separating light timber frame assemblies exposed to ISO-fire exposure.

 

Keywords: Engineering Sciences

 

Project description:

The light timber frame assemblies considered consist of solid timber members with linings of gypsum plasterboards or wood based panels. The cavity is void or is filled with insulation. Eurocode 5, part 1-2 (Dec. 2003) gives a model to calculate the failure time of the separating function of wall and floor assemblies like these. However, the rules apply only to a limited number of light timber frame assemblies. Furthermore in comparison to fire tests the calculation model can lead to conservative results.

 

The separating function (EI) of an assembly shall ensure that integrity failure (E) and insulation failure (I) does not occur during the required fire exposure. The integrity of a construction is assumed to be satisfied where fire penetration by hot gases or flames does not occur. In order to satisfy the insulation criterion the average temperature rise is limited to 140 ˇrC and the maximum temperature rise is limited to 180 ˇrC at the unexposed side of the construction. For the development of the calculation model for separating light timber frame assemblies the thermal as well as the mechanical failure of each layer shall be considered.

 

The failure time of a layer depends on many factors, for example the material properties or thickness of the layers. The fire behaviour of a layer is influenced by the others. This interaction between the several layers is an important parameter and therefore the number of layers and their position within the assembly should be considered. Other parameters like joint and connection type can be also relevant and shall be checked.

 

The different parameters will be analysed by a series of fire tests. In a first series each parameter will be tested separately, a second series looks at the combination of the several parameters. With these test results a finite element model can be verified, which will be the basis for the calculation model for separating light timber frame assemblies.

 

Publications:

  • Schleifer V. 2005-11-02. Brandverhalten zusammengesetzter Holzbauteile. SAH - Tagungsband, 37. Fortbildungskurs 2005, SAH Schweizerische Arbeitsgemeinschaft für Holzforschung, (Brandschutz im Holzbau - Grundlagen, Forschung und Umsetzung), Weinfelden, Schweiz, 79-89.
  • Schleifer V., Frangi A. 2005-08-29. Fire Tests on Light Timber Frame Wall Assemblies. CIB - W18, CIB, (Timber Structures), Karlsruhe, Germany, CIB-W18/38-16-2.
  • Schleifer V., Frangi A., Fontana M. 2005-09-14. Fire Behaviour of Light Timber Frame Wall Assemblies. IABSE Symposium Report, IABSE, (Structures and Extreme Events/ 90), Lisbon, IABSE, 296 - 297.

RDB Record ID: 9885, completed (11.07.2002 - 31.12.2009), last update: 03.01.2011

 

Project leader: Fontana, Mario, D-BAUG, IBK

ETH researchers: Erchinger, Carsten-Daniel, Frangi, Andrea, Schleifer, Vanessa,

Funding sources: Public institutions

 

Short Summary: With the revision of the present fire regulations planned in 2004 the fire authorities consider to allow the use of timber also for the fire resistance class of 60 minutes. This will then lead to new markets for timber in multi-storey buildings.

 

Keywords: Structural Engineering

 

Project description:

The Swiss fire regulations allow the use of combustible materials only for a fire resistance of up to 30 minutes. With the revision of the present fire regulations planned in 2004 the fire authorities will allow the use of timber also for the fire resistance class of 60 minutes. This will then lead to new markets for timber in multi-storey buildings.

 

The aim of the research project is to enlarge the theoretical and experimental background of the fire behaviour of timber structures for a fire resistance of 60 minutes. The main topics of the research project are following:

- fire resistance of timber connections

- fire resistance of wall and floor assemblies

- detailing

 

The results of the research project should permit the revision of the SIA Documentation 83, commonly used in Switzerland for fire resistance calculations of timber structures and to check the design methods given in Eurocode 5, part 1.2.

Brandsicherheit von Bauteilen aus Holz

RDB Record ID: 10140, completed (11.07.2002 - 31.12.2007), last update: 02.04.2008

 

Project leader: Fontana, Mario, D-BAUG, IBK

ETH researcher: Frangi, Andrea

Funding sources: Public institutions

 

Short Summary: The ongoing research projects aims at supplying basic data and information on the safe use of timber, in particular for multi-storey buildings. Further novel fire performance based design concepts are developed based on extensive element and full scale testing.

 

Keywords: Engineering Sciences

 

Project description:

Combustible building materials like timber burn at their surface, release energy and thus contribute to fire propagation and the development of smoke in case of fire. Prescriptive fire regulations often restrict the use of timber. However, in the last couple of years, many countries have started to introduce performance based fire regulations or liberalized the use of timber for buildings. These regulations open the way for new applications, in particular for an extended use of timber structures in multi-storey buildings. In taking advantage of the new possibilities it is essential to verify that fire safety of timber buildings is not lower than of buildings made of other materials.

 

The ongoing research projects aims at supplying basic data and information on the safe use of timber, in particular for multi-storey buildings. Further novel fire performance based design concepts are developed based on extensive element and full scale testing.

 

Publications:

  • Frangi, Andrea; Fontana, Mario. 2006-01-01. A design model for timber slabs made of hollow core elements in fire. Meeting, Lehrstuhl für Ingenieurholzbau und Baukonstruktionen, Universität Karlsruhe, Karlsruhe, Lehrstuhl für Ingenieurholzbau und Baukonstruktionen University Karlsruhe.
  • Frangi, Andrea; Fontana, Mario. 2005-08-01. Bemessung von Holzdecken aus Hohlkastenelementen im Brandfall. Bauphysik, Ernst & Sohn; Wiley, (4/ 27), Berlin, Ernst & Sohn Verlag für Architekten und technische Wissenschaften GmbH & Co. KG, 217-227.
  • Frangi, Andrea; Fontana, Mario. 2006-01-01. Fire behaviour of timber block walls. University of Aveiro, (2), Aveiro, Portugal, University of Aveiro, 963-974.

RDB Record ID: 14955, completed (01.10.2005 - 31.12.2009), last update: 19.01.2010

 

Project leaders: Fontana, Mario and Knobloch, Markus, D-BAUG, IBK

ETH researcher: Knobloch, Markus

Funding sources: SNF

 

Keywords: Engineering Sciences

 

Project description:

Fire design of steel structures has become an important factor for public safety and economical design of buildings, and gained world wide attention during recent years. Fires in buildings may have enormous consequences on life safety and economies. Easily applicable design methods for steel members subjected to fire are urgently needed. Local and global buckling has a strong influence on the resistance of steel structures subjected to fire. Under fire conditions, steel members heat up quickly because of the good thermal conductivity of steel. Due to elevated temperatures, the strength and stiffness of steel decreases rapidly, and the typical elastic ideal-plastic stress-strain relationship becomes distinctly non-linear. Therefore, local and global buckling in fire conditions need to be considered according to a wider range of cross-sectional and global slenderness than in ambient temperature design.

 

Commonly used calculation formulae used in fire design often consider the decrease of strength and stiffness of steel at elevated temperatures but adopt the design methods developed for ambient temperature design and elastic perfectly-plastic material behaviour unchanged. However, numerical studies show that a simple adaptation of the ambient temperature design methods produces unreliable results. A fundamental approach based on extensive research of the problem is important. A strain-based design approach developed at our institute constitutes the basis for the design of steel cross-sections subjected to fire. The intension is to develop this method for composed cross-sections (e.g. typical I-profiles and box sections), which allow taking into account thermal strains as well as global buckling.

 

  • The procedure of the research can be summarized as follows:
  • To perform preliminary analytical and numerical studies and prepare the testing procedure and facilities.
  • To perform stub-column tests at elevated temperatures in order to analyse the cross-sectional behaviour of steel section subjected to fire and local buckling.
  • To perform an experimental investigation of steel members subjected to bending and axial compression at elevated temperatures.
  • To perform a numerical parametric study using the finite element approach.
  • To develop a safe, economic and easily applicable calculation method for steel members in bending and axial compression subjected to fire.

 

The research project will provide a yet unmatched knowledge about local buckling behaviour and local-global buckling interaction behaviour of steel members in bending and axial compression subjected to fire. The project will provide an experimental and numerical database and a calculation method for steel columns subjected to local and global buckling under fire conditions.

 

Publications:

  • Knobloch, M.; Fontana, M. 2007-01-01. Compression strength of stiffened elements in fire. Structural Engineering, Mechanics and Computation, Millpress, Rotterdam, 465-466.
  • Knobloch, Markus. 2008-01-01. Local Buckling Behavior of Steel Sections Subjected to Fire. International Association for Fire Safety Science, London, 1239-1254.
  • Knobloch, Markus; Fontana, Mario. 2007-01-01. Dehnungsabhängige Berechnung vierseitig gelagerter Querschnittselemente unter Druckbeanspruchung im Brandfall. Stahlbau, Ernst & Sohn, Wiley, (8/ 76), Berlin, 521-529.
  • Knobloch, Markus; Fontana, Mario. 2006-01-01. Strain-based approach to local buckling of steel sections subjected to fire. Journal of constructional steel research, Elsevier, (1-2/ 62), Kidlington, Oxford, 44-67.
  • Niederegger Philipp, Knobloch Markus, Fontana Mario. 2006-09-20. Elements with nonlinear stress-strain relationships subjected to local buckling. Proceedings of the 2006 ICMS conference, 8.

RDB Record ID: 14956, completed (01.08.2005 - 31.12.2009), last update: 19.01.2010

 

Project leader: Fontana, Mario, D-BAUG, IBK

ETH researchers: Knobloch, Markus, Niederegger, Philipp

Funding source: Own resources of the professorship

 

Short Summary: The research project aims at developing an approach for general use with metals exhibiting non-linear stress-strain relationships to harmonise the existing calculation methods for carbon steel, stainless steel and aluminium elements subjected to local buckling.

 

Keywords: Engineering Sciences

 

Publications:

  • Niederegger, Philipp; Knobloch, Markus; Fontana, Mario. 2007-01-01. Versuche an dreiseitig gelenkig gelagerten Querschnittselementen aus Metallen mit nichtlinearem Materialverhalten. IBK Bericht, vdf Hochschulverlag, (306), Zürich, vdf Hochschulverlag.
  • Niederegger Philipp, Knobloch Markus, Fontana Mario. 2006-09-20. Elements with nonlinear stress-strain relationships subjected to local buckling. Proceedings of the 2006 ICMS conference, 8.

RDB Record ID: 267, completed (11.07.2002 - 31.12.2009), last update: 03.01.2011

 

Project leader: Fontana, Mario, D-BAUG, IBK

ETH researchers: Erchinger, Carsten-Daniel, Frangi, Andrea

Funding sources: Industry and Public institutions

 

Keywords: Engineering Sciences

 

Project description:

Holzbauteile sollen in Zukunft auch für mehrgeschossige Bauten eingesetzt werden dürfen. Dies war bis vor kurzem infolge der Brandschutzvorschriften nicht möglich. Ein umfangreiches Forschungs- und Informationsprogramm zusammen mit der Lignum und dem BUWAL ”holz21” im Umfang von ca. 7.5 Mio CHF, schafft die erforderlichen Grundlagen dazu. Dieses Teilprojekt befasst sich mit dem Brandverhalten von Bauteilen und Verbindungen bei Brandeinwirkung, insbesondere mehrschnittigen

Stahl-Holz-Stabdübelverbindungen mit innen liegenden Stahlblechen sowie Rillennagelverbindungen mit aussen liegenden Stahlblechen.

RDB Record ID: 14957, completed (01.01.2003 - 31.12.2007), last update: 02.04.2008

 

Project leader: Fontana, Mario, D-BAUG, IBK

ETH researcher: Tesar, Can Nurettin

Funding source: ETH internal grant

 

Short Summary: The aim of the project is to develop numerical methods that can predict the behavior of composite floor slabs with unprotected steel beams when subjected to fire. A new approach is used to model the shear connection between the beams and the slab.

 

Keywords: Computer Science, Engineering Sciences

RDB Record ID: 16937, completed (15.09.2000 - 14.05.2004), last update: 21.02.2006

 

Project leader: Fontana, Mario, D-BAUG, IBK

 

ETH researcher: Mischler, Adrian

Funding sources: Public institutions (e. g. federal offices)

 

Keywords: Engineering Sciences

 

Project description:

Schaffen der Grundlagen für eine probabilistisches Festigkeits- und Steifigkeitsmodell für Holz Koordination der COST E24 Aktivitäten der Schweiz Zusammen mit Gruppe Faber ID 12246

 

 

 

RDB Record ID: 17229, completed (01.06.2005 - 01.07.2009), last update: 19.01.2010

 

Project leader(s): Fontana, Mario, D-BAUG, IBK

ETH researcher: Raveglia, Elio Andrea

Funding source: KTI

 

Short Summary: Intumescent coatings applied to structural steel expand during fire and create a highly effective thermal barrier. The aim of the research project is to enlarge the theoretical and experimental background of the fire behavior of intumescent coatings and to develop a design model for fire resistance

 

Keywords: Civil Engineering

 

Publications:

  • Raveglia, E. 2006-01-01. Fire Resistance of Structural Member Protected by Intumescent Surface System. ETH, Zurich, 120-121.
  • Raveglia, E.; Fontana, M. 2007-01-01. Partial loss of fire protection of steel members protected with intumescent coatings. University of British Columbia, Vancouver, University of British Columbia, Canada, 54-54.
  • Raveglia, E.; Knobloch, M.; Fontana, M. 2006-01-01. Partial loss of fire protection and structural collapse of high-rise buildings. Servicio de Publicaciones de la Universidad de Cantabria, Santander, 41-57.

 

RDB Record ID: 18009, completed (01.01.2007 - 31.12.2009), last update: 03.01.2011

 

Project leaders: Fontana, Mario and Frangi, Andrea, D-BAUG, IBK

ETH researcher: Tesar, Can Nurettin

Funding source: Own resources of the professorship

 

Short Summary: During the cooling phase a reduction of concrete strength due to heat penetration and micro cracks may reduce the load carrying capacity of reinforced concrete structures. The ongoing research analyses the influence of the strength loss during and after the cooling on the load carrying capacity.

 

Keywords: Engineering Sciences

 

Project description:

The mechanical and thermal properties of building materials change at elevated temperatures. This change of material properties has an important influence on the load carrying and deformation behavior in case of fire. The rate of increase of temperature through the cross section in a concrete element is relatively slow and so internal zones are protected against heat. Only a small part of the cross-section is affected by the temperature action (loss of strength and stiffness). For these reasons reinforced concrete structures with adequate structural detailing usually reach high fire resistance without any additional fire protection. However after the fire has been extinguished the heat penetration into the cross section continues for hours. Additionally calcium hydroxide reformats during the cooling phase widening up micro cracks. The combination of these two phenomena can lead to a significant reduction of the compressive strength of concrete after the fire.

 

The ongoing research analyses the influence of the loss of strength during and after the cooling on the load carrying capacity of concrete elements. First numerical calculations show that after the cooling phase concrete elements can exhibit a load carrying capacity lower than during the fire. Thus the design of concrete structures based on equivalent time of standard fire exposure without cooling phase can lead to unsafe results. For this reason it may be important to take into account the cooling phase of the fire for the calculation of the load bearing capacity of concrete structures.

 

Publications:

  • Frangi, Andrea; Tesar, Can; Fontana, Mario. 2007-01-01. Tragverhalten von Betonkonstruktionen nach dem Brand. Der Bauingenieur, Springer Science+Business Media Schweiz AG, (2/ 2006), Rüschlikon, Springer Science+Business Media Schweiz AG, 24-32.
  • Frangi, Andrea; Tesar, Can; Fontana, Mario. 2007-01-01. Tragwiderstand von Betonbauteilen nach dem Brand. Bauphysik, Ernst & Sohn Verlag; Wiley, (3/ 28), Berlin, Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, 170-183.

RDB Record ID: 19111, completed (15.10.2007 - 15.10.2008), last update: 25.12.2008

 

Project leaders: Fontana, Mario and Knobloch Markus, D-BAUG, IBK

ETH researcher: Knobloch, Markus

External researcher: Mahendran, Mahen,

Funding sources: Others, Own resources of the professorship and SNF

 

Partner organizations:

Queensland University of Technology, School of Urban Development, 2 George Street GPO Box 2434, 4001, Brisbane Qld, Australia, , http://www.qut.edu.au

 

Short Summary: The research project aims at analysing the load-carrying behaviour of steel beam-columns subjected to axial compression, biaxial bending and fire. The flexural and lateraltorsional buckling resistance will be studied. The intension is to develop interaction diagrams and a calculation model.

 

Keywords: Engineering Sciences

 

Project description:

Local and overall buckling have a strong influence on the resistance of steel structures subjected to fire. In the case of fire, steel members without fire protection heat up quickly, primarily due to the typically high surface-to-volume ratio and the high thermal conductivity of steel. Due to elevated temperatures in fire, the strength and stiffness of carbon steel decreases rapidly, and the typical linear-elastic, ideal-plastic stress-strain relationship becomes distinctly non-linear. Therefore, local and overall buckling in fire conditions need to be considered according to a wider range of crosssectional and global slenderness than in ambient temperature design. The calculation models for flexural buckling and for lateral-torsional buckling of steel members subjected to fire are based on finite element calculations using the Bernoulli hypothesis disregarding local buckling effects. The load-carrying behaviour of beam-columns in major and minor axis bending and axial compression subjected to fire were previously not studied in detail.

 

The research project aims at analysing the load-carrying behaviour of steel columns and beams subjected to axial compression, biaxial bending, and fire. The flexural buckling resistance and the lateral-torsional buckling resistance of steel beam-columns at elevated temperatures will be studied. A further aim of the project is to analyse the influence of local buckling of compact sections on the overall buckling resistance. The calculation models for flexural buckling and lateral torsional buckling of steel members in bending and axial compression subjected to fire will be reviewed. The intension is to develop a calculation model for steel column-beams subjected to fire.

 

The procedure of the research can be summarized as follows:

  • To review the calculation models for steel beam-columns subjected to fire.
  • To develop a finite element model for steel members subjected to biaxial bending and axial compression at elevated temperatures.
  • To analyse the load-carrying behaviour of steel beam-columns subjected to fire by performing a numerical parametric study using the finite element model.
  • To develop a safe, economic and easily applicable calculation model.

 

The research project will provide a yet unmatched knowledge about the load-carrying behavior of steel members in bending and axial compression subjected to fire. The project will provide a numerical database and a calculation model for steel beam-columns in fire.

 

Publications:

  • Knobloch, Markus; Fontana, Mario; Frangi, Andrea. 2008-01-01. Fire resistance of steel beam-columns subjected to axial compression and biaxial bending with non-uniform bending moment distribution. Organising Committee, Fifth International Conference Structures in Fire, Singapore, Fifth International Conference Structures in Fire (SiF08), 56-67.

RDB Record ID: 19122, completed (30.06.2005 - 31.01.2006), last update: 14.01.2011

 

Project leader(s): Fontana, Mario, D-BAUG, IBK

ETH researchers: De Sanctis, Gianluca, Köhler, Jochen

External researchers: Faber, Michael H.,

Funding source: Public institutions

Partner organizations: Vereinigung Kantonaler Feuerversicherungen VKF, Bundesgasse 20, 3001, Bern, Switzerland, Tel 0041 31 320 22 22, Fax 0041 31 320 22 99, , http://www.vkf.ch/

 

Short Summary: The aim of the research project is the development of a method for fire risk assessment in residential and industrial buildings.

 

Keywords: Civil Engineering, Engineering Sciences, Risk Analysis, Risk Assessment, Structural Engineering

 

Project description:

The aim of fire safety engineering is to reduce the consequences, i.e. human and financial losses, as much as reasonably possible. Fire safety can be increased by passive and active fire safety measures. These measures can be regarded as decision alternatives in the context of fire safety management. Because fires cannot be avoided completely, certain consequences always have to be anticipated. The expected value of the consequences corresponds to the fire risk and can be influenced by fire safety measures.

 

Every measure is associated with costs and, if related to the corresponding risk reductions, a certain benefit. If the acceptability of fire safety design in terms of risk to life is fulfilled, then it is reasonable to compare the costs of fire safety measures with its benefits, i.e. to perform an economic optimization of the overall costs. This is leading to a choice of efficient fire safety measures regarding risk to life as well as financial losses. To compare and select efficient measures a generic and quantitative fire risk assessment method is required.

 

Generic risk assessment facilitates quantification of the expected values of consequences due to fire events in dependence of risk indicators and fire safety measures. Both may be associates with uncertainties due to lack of knowledge and randomness. A probabilistic model allows to consider these uncertainties consistently and to represent the physical processes of a fire hazard.

RDB Record ID: 20110, ongoing (01.05.2007), last update: 23.01.2008

 

Project leader(s): Fontana, Mario and Knobloch Markus, D-BAUG, IBK

ETH researcher: Knobloch, Markus

Funding source(s): Others, Own resources of the professorship

Partner organizations: Tokyo Institute of Technology, Japan, http://www.titech.ac.jp/home.html

 

Short Summary: The collaborative research project at Materials and Structures Laboratory, Tokyo Institute of Technology and Institute of Structural Engineering, ETH Zurich aims at experimentally and numerically analyzing the local buckling behavior of unstiffened elements and crux profiles subjected to fire.

 

Keywords: Engineering Sciences

 

RDB Record ID: 20673, ongoing (15.05.2008), last update: 19.10.2010

 

Project leader(s): Fontana, Mario and Knobloch, Markus, D-BAUG, IBK

ETH researcher: Neuenschwander, Martin

Funding sources: ETH internal grant, Industry and Own resources of the professorship

 

Short Summary: The research project aims at analyzing the load-carrying behavior of concrete-filled steel tubular columns with steel core subjected to fire.

 

Keywords: Civil Engineering, Engineering Sciences

 

Project description:

Fire design is an important factor in the safe and economical design of steel and steel-concrete composite structures. Fires in buildings may have enormous consequences on life safety and economies. It is necessary to get a fundamental knowledge of the structural behavior of steel-concrete composite members in fire and develop safe, economical and easy applicable calculation models, especially in case of buckling. Concrete-filled steel tubular columns with steel cores have an attractive architectural appearance due to the visible steel of the tube and the high slenderness of the column. Concrete-filled steel tube sections with steel cores are used for highly loaded columns and/or for minimizing the size of the column. Under fire conditions the steel tube is directly exposed to the fire and heats up quickly. The concrete inside the tube decelerates the heating of the steel core. The reduced strength and stiffness of steel and concrete at elevated temperatures must be considered for calculating both the cross-sectional resistance and slender column strength of steel-concrete composite sections.

 

The research project aims at analyzing the load-carrying behavior of concrete-filled steel tubular columns with steel core subjected to fire. The intention is to develop a analytical model for this kind of steel-concrete composite sections subjected to axial compression and fire. This model will allow taking into account flexural buckling, residual stresses, temperature-dependent material properties for steel and concrete, thermal strains and stresses as well as standard ISO and natural fire exposures. After this, the project aims at improving the cross-sections used for the composite columns.

 

Procedure

  • To analyze existing fire tests on slender columns with concrete-filled steel tubes with steel core.
  • To extend the knowledge about the fire behavior of steel-concrete composite columns by performing a comprehensive numerical parametric study using the finite element approach.
  • To develop a safe, economic and easily applicable calculation model for the temperature-dependent cross-sectional resistance and the slender column strength.

RDB Record ID: 21023, completed (12.09.2008 - 31.12.2011), last update: 17.12.2012

 

Project leaders: Fontana, Mario and Frangi, Andrea, D-BAUG, IBK

Funding source: Industry

 

Short Summary: The aim of the research project is to enlarge the theoretical and experimental background on the fire performance of concrete made of blended cement in comparison to ordinary Portland. Particular attention is given the reduction of concrete strength at high temperatures and during the cooling phase.

 

Keywords: Concrete Engineering, Concrete Technology

 

Publications:

  • Eike Klingsch, Andrea Frangi, Mario Fontana. 2010-01-04. Concrete Residual Strength in Compression: Blended Cements versus Ordinary Portland Cement. Studi e Richerche – Studies and Researches, A. Migliacci, P. Gambarova, P. Ronca, (29), Milan, Italy, Politecnico di Milano, 131-154.
  • Klingsch, Eike; Frangi, Andrea; Fontana, Mario. 2009-01-01. Experimental Analysis of Concrete Strength at High Temperatures and After Cooling. Czech Technical University, Prague, Czech Technical Iniversity in Prague, 216-221.

RDB Record ID: 21026, completed (01.07.2008 - 30.06.2010), last update: 17.12.2012

 

Project leaders: Fontana, Mario and Frangi, Andrea

ETH researcher: Klingsch, Eike Wolfram

Funding source: KTI

 

Short Summary: The aim of the research project is to enlarge the theoretical and experimental background of the fire behaviour of fire protective coatings applied to concrete and to develop a design model for the calculation of the fire resistance of concrete elements protected by coatings.

 

Keywords: Engineering Sciences

 

Project description:

Spalling of concrete may significantly decrease the fire resistance of concrete structures exposed to fire, in particular in the case of high- and ultrahigh-strength concrete. Coatings applied like paint to the concrete surface creates a highly effective thermal barrier for fire, reducing the risk of spalling. The aim of the research project is to enlarge the theoretical and experimental background of the fire behaviour of fire protective coatings applied to concrete and to develop a design model for the calculation of the fire resistance of concrete elements protected by coatings.

 

Publications:

  • Klingsch, Eike. 2011-01-01. Abplatzen und Restfestigkeit von Beton nach Feuereinwirkung. SIA Schweizerischer Ingenieur- und Architektenverein, Zürich, 25-44.
  • Klingsch, Eike. 2011-01-01. Hochtemperaturverhalten von UHPC. Verein Deutscher Ingenieure: VDI-Berichte, Deutscher Ingenieur-Verlag, (2126), Düsseldorf, 15-36.
  • Klingsch, Eike; Frangi, Andrea; Fontana, Mario. 2011-01-01. Fire Protection of High-Performance Concrete using Protective Lining. Applied mechanics and materials, Trans Tech Publications, (82), Stäfa, 758-763.
  • Klingsch, Eike; Frangi, Andrea; Fontana, Mario. 2011-03-01. High- and Ultrahigh-Performance Concrete, A Systematic Experimental Analysis on Spalling. SP / ACI International, American Concrete Institute, (279), Farmington Hills, MI, 9-1-9-50.

RDB Record ID: 21027, completed (01.01.2008 - 31.12.2010), last update: 28.01.2011

 

Project leaders: Fontana, Mario and Frangi, Andrea, D-BAUG, IBK

ETH researchers: no entry

Funding sources: Industry

 

Short Summary: A new composite slab with integrated installation floor is under development and testing. The new composite floor system is based on half cellular steel beams made of hot-rolled sections that are cast into the concrete.

 

Keywords: Engineering Sciences

 

Project description:

A large variety of composite floor systems are widely used for buildings throughout the world. They allow fast erection and are light weight. However in central Europe they are mostly not cost efficient in comparison to in situ concrete flat slabs and have therefore a small market share.

 

The Institute of Structural Engineering IBK of ETH Zurich in collaboration with the Chair of Metal Construction of the Technische Universität München is currently developing and testing a new composite slab with integrated installation floor. The new composite floor system is based on half cellular steel beams made of hot-rolled sections that are cast into the concrete. The composite action between cellular beam and concrete slab is provided by reinforcing steel welded to the cellular beam, welded headed studs or other kinds of shear connectors are not required. Prefabricated elements with pi-cross-sections are favourable for production and transportation.

 

The main advantage of the new composite floor system is the integration of the raised installation floor into the slab without additional costs. The openings in the cellular beams allow placing installations in the transverse direction, thus providing excellent flexibility to the designers during construction and to the user especially during use when changing installations. Further, the concrete slab provides fire resistance at no extra cost.

RDB Record ID: 21029, ongoing (01.09.2008), last update: 10.12.2008

 

Project leaders: Fontana, Mario and Frangi, Andrea, D-BAUG, IBK

ETH researcher(s): no entry

Funding source: Industry

 

Short Summary: Objective of the research project is the development of a calculation model for the fire resistance of cross-laminated solid timber panels taking into account the behaviour of the bonding adhesive at high temperature.

 

Keywords: Engineering Sciences

 

Project description:

Cross-laminated solid timber panels represent an interesting technical and economical product for modern timber structures. The use of large prefabricated cross-laminated solid timber panels for load-bearing wall and floor assemblies has become increasingly popular in particular for residential timber buildings. Fire tests on cross-laminated solid timber panels showed that the fire behavior of cross-laminated solid timber panels depends on the behaviour of the single layers. If the charred layers fall off, an increased charring rate needs to be taken into account. The same effect is observed for initially protected timber members after the fire protection has fallen off. Thus the fire behaviour of cross-laminated solid timber panels can be strongly influenced by the thickness and the number of layers. Further, the position of the panel (horizontal for slabs, vertical for walls) as well as the behaviour of the bonding adhesive at high temperature can influence the falling of the charred layers and thus play an important role in the evaluation of the fire behaviour of crosslaminated solid timber panels.

 

Objective of the research project is the experimental and numerical analysis of the fire behavior of cross-laminated solid timber panels. The influence of several parameters (thickness and number of layers, bonding adhesive used, joint configuration) on charring of cross-laminated solid timber panels will be studied with a series of fire tests. The results of the fire tests in addition to numerical calculations will permit the development of a calculation model for the fire resistance of cross-laminated solid timber panels.

RDB Record ID: 21030, completed (01.06.2010 - 31.05.2013), last update: 13.01.2010

 

Project leaders: Fontana, Mario and Frangi, Andrea, D-BAUG, IBK

ETH researchers: Klippel, Michael

Funding source: Industry

 

Short Summary: The aim of the research project is the development of a calculation model for the fire resistance of glued-laminated timber beams taking into account the behaviour of the bonding adhesive at high temperature.

 

Keywords: Engineering Sciences

 

Project description:

The structural behaviour of glued-laminated timber beams is strongly influenced by the behavior of finger joints. The behaviour of the adhesive used for bonding can influence the fire resistance of glued-laminated timber beams. The aim of the research project is the development of a calculation model for the fire resistance of glued-laminated timber beams taking into account the behaviour of the bonding adhesive at high temperature.

RDB Record ID: 22412, completed (01.01.2009 - 30.11.2012), last update: 19.12.2012

 

Project leader: Fontana, Mario, D-BAUG, IBK

ETH researchers: Fischer, Katharina, Köhler, Jochen,

External researcher: Faber, Michael H.,

Funding source(s): Public institutions (e. g. federal offices)

Partner organizations: Vereinigung Kantonaler Feuerversicherungen VKF, Bundesgasse 20, 3001, Bern, Switzerland, Tel 0041 31 320 22 22, Fax 0041 31 320 22 99, ,

externe Seitehttp://www.vkf.ch/

 

Short Summary: Costs of fire safety measures have to be balanced with the benefits they provide. Code provisions in fire safety regulations should be justified by economic efficiency. The aim of the project is to evaluate the efficiency of different measures as a basis for code-making decisions.

 

Keywords: Engineering Sciences

 

Project description:

The sum of fire losses in Swiss buildings exceeds 300 Mio. Swiss Francs per year. Fire prevention measures are reducing this amount. Yet the requirements in the fire safety codes need to be justified. Costs of fire safety measures have to be balanced with the benefits they provide by reducing fire losses. Of course, this optimization cannot be done only by economic reasoning. Each year, in Switzerland 30-40 people die in building fires. However, societal resources for life saving activities are limited and should be spent for the most effective alternatives available.

 

The objective of this research project is the development of methods for assessing the efficiency of fire safety measures from a societal point of view. For this purpose the basic principles of an economic optimization in the area of preventive fire safety are discussed. An analysis of Swiss insurance data serves as a starting point for the assessment of fire risk in the Swiss building portfolio. The results of the data analysis are complemented by engineering methods for the assessment of fire risk. By means of four case studies it is shown how economic optimization can be applied to practical questions by consistently accounting for all relevant uncertainties. The results can be used as an objective basis for societal decision-making, e.g. for future code revisions.

 

Publications:

  • Fischer, Katharina; Kohler, Jochen; Fontana, Mario; Faber, Michael H. 2012-07-01. Wirtschaftliche Optimierung im vorbeugenden Brandschutz. IBK Report, Institut für Baustatik und Konstruktion, Eidgenössische Technische Hochschule Zürich, (338), Zürich.
  • Fischer, Markus; Fontana, Mario; Krämer, Katharina. 2010-01-01. Wirtschaftliche Optimierung im vorbeugenden Brandschutz. Die Volkswirtschaft, Swissprinters St. Gallen AG, (6/ 83), St. Gallen, 60-63.

RDB Record ID: 24168, completed (01.10.2010 – 31.12.2011), last update: 23.11.2010

 

Project leaders: - Fontana, Mario and Knobloch, Markus, D-BAUG, IBK

ETH researchers: Pauli, Jacqueline, Somaini, Diego,

Funding source: SNF

 

Short Summary: The results of the former research project show the distinctive influence of thermal creep on the cross-sectional capacity and slender column and beam-column strength in fire. The project aims at analyzing the influence of thermal creep on the stability behavior of steel beam-columns in fire.

 

Keywords: Engineering Sciences

 

Project description:

Background

The resistance of steel columns subjected to fire is strongly influenced by the temperature-dependent cross-sectional capacity considering local buckling effects, global buckling effects and thermal creep effects. Under fire conditions, steel members without fire protection heat up quickly, primarily due to the typically high surface-to-volume ratio and the high thermal conductivity of steel. Due to elevated temperatures under fire conditions, the strength and stiffness of steel decreases rapidly. Furthermore thermal creep has to be considered for temperatures above approximately 400ˇrC to 500ˇrC.

 

Commonly used analytical models used in fire design do not explicitly consider the effect of thermal creep on the structural stability of steel members subjected to fire. Comprehensive fundamental research on the influence of thermal creep on the cross section capacity as well as slender column and beam-column strength has not been performed so far. However, the research results achieved during a former research project as well as the few research results given in literature indicate that a comprehensive research in that important field is required for structural safety.

 

Aim

The results of the former research project show the distinctive influence of thermal creep on the cross-sectional capacity and slender column and beam-column strength in fire. The promising results and findings of the former research will be extended and generalized by performing basic research on the influence of thermal creep on the fundamental structural stability behaviour of steel columns and beam-columns subjected to fire.

 

The research project will provide a broad knowledge on the influence of thermal creep on the cross-sectional behaviour and buckling behaviour of steel members subjected to fire. The project will provide an experimental and numerical database and analytical models for the influence of thermal creep on the cross-sectional capacity and structural behaviour of steel columns and beamcolumns subjected to fire.

 

Procedure

The procedure of the research can be summarised as follows:

  • To perform steady-state and transient-state tensile material coupon furnace tests to analyse the influence of thermal creep on the fundamental material behaviour of structural steel in fire.
  • To perform stub-column tests at elevated temperatures considering different strain rates under steady-state conditions to analyse the influence of thermal creep on the cross section capacity of steel sections subjected to compression and combined compression and bending at elevated temperatures using an electric furnace.
  • To perform slender column and beam-column tests under both steady-state and transient-state conditions to analyse the influence of thermal creep on the structural stability behaviour of steel members subjected to fire using an electric furnace. To extend the basic knowledge from tests on the influence of thermal creep on the buckling behavior of steel members subjected to fire by performing a numerical parametric study using the finite element approach.
  • To develop models analytically describing the influence of thermal creep on the cross-sectional capacity and fundamental structural stability behaviour in fire.

 

 

 

RDB Record ID: 24171, completed (01.07.2009 – 31.12.2009), last update: 15.11.2010

 

Project leaders: Fontana, Mario, and Knobloch, Markus

ETH researcher: Klippel, Michael

Funding sources: Industry and Own resources of the professorship

 

Short Summary: The use of profiled steel sheets in combination with a concrete layer results in a good solution for the construction of building floors. The project aims at analysing the longitudinal shear capacity of composite floors during service life.

 

Keywords: Engineering Sciences

 

Project description:

Background and aim

The use of profiled steel sheets in conjunction with a concrete layer results in a good solution for the construction of building floors. Steel deck concrete composite slabs gain structural benefits, allow fast erection and are lightweight. Two design methods, namely the m-k-method and the partial connection method, are mainly used for the design of composite slabs. The reconstruction of Terminal B of Zurich airport allowed experimentally analysing the longitudinal shear bond behavior of composite slabs with profiled steel sheets after 35 years in service.

 

Terminal B at Zurich Airport was built in 1974. The two-storey building of Terminal B consisted of HEM 360 columns and virendeel girders. Secondary IPE 360 beams constituted the supports of the composite floor slab with profiled steel sheeting. Terminal B of Zurich airport is converted to implement the Schengen agreement with the European Union. As a precondition to reuse the existing structure it had to be shown that the structure still meets the safety and serviceability requirements in particular the longitudinal shear capacity of the composite slabs after 35 years in service.

 

Description

Ten full-scaled tests on simple beams with different shear span lengths, two continuous beam tests, two cantilever beam test, two punching shear tests and two tests on floor openings were performed in situ to experimentally investigate the load-carrying behaviour, and in particular the longitudinal shear capacity of the composite slabs. The test results on simple beams were assessed with the m-k-method and the partial shear connection method.

 

Main result

The results show that the profiled steel sheeting after 35 years in use still features good longitudinal shear strength and is fit for reuse as slab of Dock B of Zurich airport.

RDB Record ID: 27453, ongoing (01.01.2012), last update: 17.12.2012

 

Project leader: Fontana, Mario, D-BAUG, IBK

ETH researchers: Klingsch, Eike Wolfram, Knobloch, Markus

Funding source: Others

 

Short Summary: New, innovative cardboard for sustainable construction is analyzed in this project. The cardboard elements are coated with a cementitios coating. Main focus is put on the mechanical properties of coated and laminated cardboard as well as time and environmental conditions e.g. temperature, moisture.

 

Keywords: Engineering Sciences, Environmental Technology

 

Publications:

  • Klingsch, Eike Wolfram; Knobloch, Markus; Fontana, Mario. 2012-01-01. Development of innovative light-weight cardboard elements for sustainable constructions. IABSE c/o ETH Hönggerberg, Zürich, 605-606.
  • Pohl, Almut. 2009-01-01. Strengthened corrugated paper honeycomb for application in structural elements. IBK Bericht, vdf Hochschulverlag AG an der ETH Zürich, (318), Zürich.

RDB Record ID: 28436, ongoing (01.01.2012), last update: 27.01.2012

 

Project leader: Fontana, Mario, D-BAUG, IBK

ETH researcher(s): no entry

Funding source: Own resources of the professorship

 

Short Summary: Experimental tests and analysis on explosive spalling of HPC and UHPC shows that high pore pressure, pore size and low permeability are the key factors. Numerical calculations in addition to the comparison will permit the development of a simulation strategy for spalling behavior of HPC and UHPC.

 

Keywords: Engineering Sciences

 

Project description:

High (HPC) and ultrahigh performance concrete (UHPC) is playing a more and more important role in civil engineering. However, when these concrete are subjected to fire, the high temperature might cause spalling, which significantly decrease the mechanical properties of the material, influencing the structural performance. It is important to study the spalling behavior of high and ultrahigh performance concrete.

 

The results of many experiments and analysis on explosive spalling of HPC and UHPC shows that high pore pressure and low permeability are the key factors of spalling. However, the mechanisms are still under investigation. In consideration of the high cost of experiments and the advantage of numerical simulation, simulations predicting the spalling behavior will be carried out. The influence of several parameters (pore pressure, permeability, pore size) on the simulation of concrete panels will be studied and compared with the experiments result. The results of the numerical calculations in addition to the comparison will permit the development of a simulation strategy for spalling behavior of high and ultrahigh performance concrete.

RDB Record ID: 29726, completed (16.09.2008 – 31.03.2014), last update: 18.01.2013

 

Project leader: Fontana, Mario, D-BAUG, IBK

ETH researcher: Caduff, Daniel,

Funding source: ETH internal grant

 

Short Summary: The aim of the project is to investigate the mechanical properties and the fracture mechanism of regular lattice structures which are used for numerical simulations of fracture processes in concrete where the failure mode in compression should get improved.

 

Keywords: Engineering Sciences

 

Project description:

The aim of the project is to investigate the mechanical properties and the fracture mechanism of regular lattice structures. Beam-lattice models are a convenient tool for analysing the mechanical and fracture behavior of various (disordered) materials and structures. Projecting a material structure on top of a lattice and assigning properties of various material phases of the individual lattice elements allows modelling almost any material in which simple one dimensional constitutive equations are sufficient. Stability problems like buckling were not investigated until now.

 

Regular lattice structures are produced with rapid prototyping. In a first step, single beam elements are tested under tension and compression in a micro loading device to establish the mechanical properties of the used material.

 

In a second step, lattice structures are tested under tension and compression. During the experiments, the strain distribution on the surface of the specimen is measured using 3 dimensional video image correlation.

 

The influence of the beam geometry and the node stiffness in regards to the behavior of the lattice structure is established with the measured properties of single beams trough numerical simulation. With the calibrated parameters of the model, it is possible to design a structure which is more capable to simulate fracture processes in concrete under compression.

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