Mechanical properties of structural steels at high temperatures and after cooling down
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Doctoral thesis (article-based)
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Date
2007-04-20
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Language
en
Pages
37, [90]
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Helsinki University of Technology Laboratory of Steel Structures publications, Teknillisen korkeakoulun teräsrakennetekniikan laboratorion julkaisuja, 32
Abstract
Behaviour of mechanical properties of different steel grades at elevated temperatures need to be well known to understand the behaviour of steel and composite structures in fire. Quite commonly simplified material models are used to estimate the structural fire resistance of steel structures. In more advanced methods, for example in finite element or finite strip analyses, it is important to use accurate material data to obtain reliable results. To study thoroughly the behaviour of certain steel structure at elevated temperatures, one should use the material data of the steel obtained by testing. Extensive experimental research has been carried out in the Laboratory of Steel Structures at Helsinki University of Technology in order to investigate mechanical properties of several structural steels at elevated temperatures by using mainly the transient state tensile test method. In this thesis a collection of test results of the behaviour of mechanical properties of different steel grades at elevated temperatures is presented with analysis of the test results. The tests have been carried out at Helsinki University of Technology during the past about 12 years. The aim of these tests has been to evaluate the accuracy of existing design values for the mechanical properties of structural steel and to support other different research projects aimed at studying the behaviour of steel or composite structures in fire. The results are presented with a comparison to the European design standard (EN1993-1-2) for structural fire design of steel structures, which is already the officially accepted standard in the EU countries and certainly will be largely in use in the near future. The results are quite well adopted and referred in other different research projects. The main aim of this research was to provide results to other researchers and design engineers in the field of structural fire engineering to improve structural fire safety in the future.Teräsrakenteiden paloteknisessä mitoituksessa tarvitaan yksityiskohtaista tietoa materiaalien käyttäytymisestä korkeissa lämpötiloissa. Rakennusten paloturvallisuuden kannalta on olennaista, että tulipalon aiheuttaman lämpötilan nousun aiheuttamat muutokset materiaalien ja rakenteiden kestävyyteen tunnetaan sekä palonaikaisen kestävyyden että korjausrakentamisen kannalta myös tulipalon jälkeisen tilanteen osalta. Kokeellinen materiaalitutkimus on varmin tapa arvioida näitä ominaisuuksia. Teknillisen korkeakoulun Teräsrakennetekniikan laboratoriossa on vuosina 1993-2006 tehty laajaa kokeellista tutkimusta erilaisten rakenneterästen ja ruostumattomien terästen ominaisuuksien selvittämiseksi palolämpötiloissa. Kokeelliset tutkimukset on tehty käyttäen ns. transienttikoemenetelmää, jossa materiaalin käyttäytyminen vastaa hyvin rakennemateriaalin käyttäytymistä tulipalotilanteessa. Lisäksi on tutkittu myös teräksen jäännöslujuutta jäähtymisen jälkeen, jotta voitaisiin arvioida kantavien teräsrakenteiden kestävyyttä myös tulipalon jälkeen. Tässä väitöskirjatutkimuksessa tuotetaan kootusti perustavaa tietoa rakenneteräksen käyttäytymisestä korkeissa lämpötiloissa. Tavoitteena on ollut suunnittelussa ja myös palo-onnettomuuksien arvioinnissa käytettävän perustietämyksen lisääminen, jotta luottamusta rakenteelliseen paloturvallisuuteen voitaisiin parantaa.Description
Keywords
fire, steel structures, material testing, high-temperature testing, transient state, mechanical properties, elevated temperatures
Other note
Parts
- Outinen J., Kesti J., Mäkeläinen P., Fire design model for structural steel S355 based upon transient state tensile test results, Journal of Constructional Steel Research, Vol. 42, No. 3, pp. 161-169, Elsevier Science Ltd, 2/1997. [article1.pdf] © 1997 Elsevier Science. By permission.
- Mäkeläinen P., Outinen J., Kesti J., Fire design model for structural steel S420M based upon transient-state tensile test results, Journal of Constructional Steel Research, Vol. 48, No. 1, pp. 47-57, Elsevier Science Ltd, 8/1998. [article2.pdf] © 1998 Elsevier Science. By permission.
- Mäkeläinen P., Outinen J., Mechanical properties of an austenitic stainless steel at elevated temperatures, Journal of Constructional Steel Research, Vol. 46, Nos. 1-3, pp. 455, Elsevier Science Ltd, 2/1998. Full paper published in the Proceedings of the Second World Conference on Steel Construction, San Sebastián, Spain, 1998. [article3.pdf] © 1998 Elsevier Science. By permission.
- Outinen J., Kaitila O., Mäkeläinen P., A study for the development of the design of steel structures in fire conditions, Proceedings of the 1st International Workshop on Structures in Fire, Copenhagen, Denmark, 2000, pp. 267-281. [article4.pdf] © 2000 by authors.
- Outinen J., Mäkeläinen P., Effect of high temperature on mechanical properties of cold-formed structural steel, Puthli R., Herion S. (editors), Tubular Structures IX, Proceedings of the Ninth International Symposium and Euroconference on Tubular Structures, Düsseldorf, Germany, 3-5 April 2001, A.A. Balkema Publishers, The Netherlands, 2001, pp. 439-444.
- Outinen J., Mäkeläinen P., High-temperature strength of structural steel and residual strength after cooling down, M. Ivanyi (editor), Proceedings of the International Colloquium on Stability and Ductility of Steel Structures, Budapest, Hungary, 2002, Budapest University of Technology and Economics, pp. 751-760.
- Outinen J., Mäkeläinen P., Mechanical properties of structural steel at elevated temperatures and after cooling down, Fire and Materials, Vol. 28, Nos. 2-4, pp. 237-251, John Wiley & Sons, 2004.
- Outinen J., Mechanical properties of structural steel at elevated temperatures and after cooling down, Proceedings of the 10th International Fire and Materials Conference, San Francisco, USA, 29-31 January 2007, Interscience Communications Limited, 2007, Delegates handbook, pp. 125-126, full article in included CD. [article8.pdf] © 2007 Interscience Communications. By permission.