An investigation of overturning moments of portal frames at elevated temperatures

Mahbubur Rahman, James Lim, Robert Hamilton, Tugrul Comlekci, David Pritchard, Yixiang Xu

Research output: Chapter in Book/Report/Conference proceedingChapter

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Abstract

In the UK, single-storey steel buildings account for over half of the constructional steelwork due to its ease of fabrication and cost-efficiency. The most common of these are portal frames. One of the major disadvantages of constructional steel is its sensitivity to fire, as steel looses strength and stiffness rapidly. For this reason, fire protection is often required, which can add to the expense of structure. In fire, the rafter often loses stability through a snap-through-buckling mechanism (see Fig. 1.). This, however, can be capable of restabilising at high deflections, when the roof has inverted. In static analysis methods, only the initial loss of stability can be determined. In fire conditions it is imperative that boundary walls stay close to vertical, so that fire is not allowed to spread to adjacent property. The current UK fire design guide (Ref.1) provided by Steel Construction Institute (SCI) provides a method for the determination of the overturning moment at the column base that must be resisted in order to prevent stability of walls. However, the method makes a number of arbitrary assumptions and does not attempt to model the true behaviour of the frame during fire.
Original languageEnglish
Title of host publicationProceedings of International Conference Applications of Structural Fire Engineering
Number of pages6
Publication statusPublished - 2009

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Fires
Temperature
Steel
Steel construction
Fire protection
Static analysis
Roofs
Buckling
Stiffness
Fabrication
Costs

Keywords

  • fire safety
  • fire engineering
  • structural fire engineering

Cite this

Rahman, M., Lim, J., Hamilton, R., Comlekci, T., Pritchard, D., & Xu, Y. (2009). An investigation of overturning moments of portal frames at elevated temperatures. In Proceedings of International Conference Applications of Structural Fire Engineering
Rahman, Mahbubur ; Lim, James ; Hamilton, Robert ; Comlekci, Tugrul ; Pritchard, David ; Xu, Yixiang. / An investigation of overturning moments of portal frames at elevated temperatures. Proceedings of International Conference Applications of Structural Fire Engineering. 2009.
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abstract = "In the UK, single-storey steel buildings account for over half of the constructional steelwork due to its ease of fabrication and cost-efficiency. The most common of these are portal frames. One of the major disadvantages of constructional steel is its sensitivity to fire, as steel looses strength and stiffness rapidly. For this reason, fire protection is often required, which can add to the expense of structure. In fire, the rafter often loses stability through a snap-through-buckling mechanism (see Fig. 1.). This, however, can be capable of restabilising at high deflections, when the roof has inverted. In static analysis methods, only the initial loss of stability can be determined. In fire conditions it is imperative that boundary walls stay close to vertical, so that fire is not allowed to spread to adjacent property. The current UK fire design guide (Ref.1) provided by Steel Construction Institute (SCI) provides a method for the determination of the overturning moment at the column base that must be resisted in order to prevent stability of walls. However, the method makes a number of arbitrary assumptions and does not attempt to model the true behaviour of the frame during fire.",
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author = "Mahbubur Rahman and James Lim and Robert Hamilton and Tugrul Comlekci and David Pritchard and Yixiang Xu",
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Rahman, M, Lim, J, Hamilton, R, Comlekci, T, Pritchard, D & Xu, Y 2009, An investigation of overturning moments of portal frames at elevated temperatures. in Proceedings of International Conference Applications of Structural Fire Engineering.

An investigation of overturning moments of portal frames at elevated temperatures. / Rahman, Mahbubur; Lim, James; Hamilton, Robert; Comlekci, Tugrul; Pritchard, David; Xu, Yixiang.

Proceedings of International Conference Applications of Structural Fire Engineering. 2009.

Research output: Chapter in Book/Report/Conference proceedingChapter

TY - CHAP

T1 - An investigation of overturning moments of portal frames at elevated temperatures

AU - Rahman, Mahbubur

AU - Lim, James

AU - Hamilton, Robert

AU - Comlekci, Tugrul

AU - Pritchard, David

AU - Xu, Yixiang

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PY - 2009

Y1 - 2009

N2 - In the UK, single-storey steel buildings account for over half of the constructional steelwork due to its ease of fabrication and cost-efficiency. The most common of these are portal frames. One of the major disadvantages of constructional steel is its sensitivity to fire, as steel looses strength and stiffness rapidly. For this reason, fire protection is often required, which can add to the expense of structure. In fire, the rafter often loses stability through a snap-through-buckling mechanism (see Fig. 1.). This, however, can be capable of restabilising at high deflections, when the roof has inverted. In static analysis methods, only the initial loss of stability can be determined. In fire conditions it is imperative that boundary walls stay close to vertical, so that fire is not allowed to spread to adjacent property. The current UK fire design guide (Ref.1) provided by Steel Construction Institute (SCI) provides a method for the determination of the overturning moment at the column base that must be resisted in order to prevent stability of walls. However, the method makes a number of arbitrary assumptions and does not attempt to model the true behaviour of the frame during fire.

AB - In the UK, single-storey steel buildings account for over half of the constructional steelwork due to its ease of fabrication and cost-efficiency. The most common of these are portal frames. One of the major disadvantages of constructional steel is its sensitivity to fire, as steel looses strength and stiffness rapidly. For this reason, fire protection is often required, which can add to the expense of structure. In fire, the rafter often loses stability through a snap-through-buckling mechanism (see Fig. 1.). This, however, can be capable of restabilising at high deflections, when the roof has inverted. In static analysis methods, only the initial loss of stability can be determined. In fire conditions it is imperative that boundary walls stay close to vertical, so that fire is not allowed to spread to adjacent property. The current UK fire design guide (Ref.1) provided by Steel Construction Institute (SCI) provides a method for the determination of the overturning moment at the column base that must be resisted in order to prevent stability of walls. However, the method makes a number of arbitrary assumptions and does not attempt to model the true behaviour of the frame during fire.

KW - fire safety

KW - fire engineering

KW - structural fire engineering

UR - http://eurofiredesign.fsv.cvut.cz/Proceedings/X_Annex.pdf

M3 - Chapter

SN - 978-80-01-04266-3

BT - Proceedings of International Conference Applications of Structural Fire Engineering

ER -

Rahman M, Lim J, Hamilton R, Comlekci T, Pritchard D, Xu Y. An investigation of overturning moments of portal frames at elevated temperatures. In Proceedings of International Conference Applications of Structural Fire Engineering. 2009