Abstract
Current practice for the design of steel beam-columns (i.e., members under combined axial load and bending) subject to fire is to calculate the capacity of these members assuming a uniform temperature distribution through the depth of the section. This assumption may be acceptable for some members, but there are cases where the member will be heated nonuniformly, thereby developing a thermal gradient through its depth. This paper analyzes the effects of thermal gradients on the combined axial load (P) -moment (M) yield capacity of beam-columns and compares the yield capacity of members with temperature gradients to those with uniform temperature profiles. The prototype beam-columns used in this study are wide-flange (WF) steel sections that are part of a high-rise moment-resisting steel building. This study evaluates the effects of plate thickness, section depth, and the direction of bending (i.e., strong versus weak axis) on the plastic P-M interaction diagram of WF sections with thermal gradients. Results show that a thermal gradient may have a significant effect on the yield capacity of beam-columns, and evaluations that are made assuming a uniform temperature through the section may lead to overestimations or underestimations of the true strength of the section.
Original language | English (US) |
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Pages (from-to) | 874-880 |
Number of pages | 7 |
Journal | Journal of Structural Engineering |
Volume | 134 |
Issue number | 6 |
DOIs | |
State | Published - 2008 |
All Science Journal Classification (ASJC) codes
- Civil and Structural Engineering
- Building and Construction
- General Materials Science
- Mechanics of Materials
- Mechanical Engineering
Keywords
- Axial loads
- Beam columns
- Fire resistance
- Steel frames
- Thermal gradient