Practical Predictive Formulas for Residual Strengths of Fire-Damaged Normal Strength Reinforced Concrete Square Columns

화해를 입은 보통강도 철근콘크리트 정방형 기둥의 실용 잔존내력식

  • Lee, Cha-Don (Dept. of Architectural Engineering, Chung-Ang University) ;
  • Lee, Seung-Whan (Dept. of Architectural Engineering, Chung-Ang University) ;
  • Lee, Chang-Eun (Dept. of Architectural Engineering, Chung-Ang University)
  • Published : 2006.02.28


The behavior of concrete structures subject to fire is complex, depending on many factors. The factors usually considered in research include the level and endurance of temperatures in concrete and reinforcing bars, the mechanical properties of the steel and concrete, moisture contents, cover thickness, existence of eccentricity, and member geometry among others. Although there are a few sophisticated numerical models which can trace the effects of these important parameters on the residual capacity of reinforced concrete columns damaged by fire, practical predictive formulas are in need for rapid yet reasonable assessment in practice. The practical formulas are developed in this study for fire-damaged normal strength reinforced concrete square columns, which can approximate the predictions of those sophisticated numerical models with ease in use. The formulas take into account the effects of exposure time to fire, concrete strength, reinforcement ratio and sectional area. The developed formulas are seen to correlate with the predictions of numerical model in a reasonable agreement. Some examples are also presented in determining the residual strength, safety and additionally needed strengths for a fire-damaged reinforced concrete column.


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