The high-temperature properties of mild steels were studied by comparing the test results of Kwon and the yield strength, tangent modulus predicted by the design provisions of ASCE and Eurocode(EC3). The column strengths for steel members at high temperatures were determined by the elastic and inelastic buckling strengths according to elevated temperatures. The material properties at high temperatures should be used in the strength evaluations of high temperature members. The buckling strengths obtained from the AISC, EC3 and approximate formula proposed by Takagi et al. were compared with ones calculated by the material nonlinear analysis using the EC3 material model. The newly simplified formulas for yield stress, tangent modulus, proportional limit and buckling strength which were proposed through a comparative study of the material properties and buckling strengths. The buckling strengths of proposed formulas were approximately equivalent to ones obtained from the formulas of Takagi et al. within 4% . They were corresponded to the lower bound values among the buckling strengths calculated by the design formulas and inelastic buckling analysis.

Abstract
 1. 서론
 2. 고온 강재의 재료 특성 비교와단순화 모델
  2.1 항복 강도
  2.2 탄성 계수와 비례 한도
 3. 강재의 온도 변화에 따른 좌굴 강도
  3.1 EC3 재료 모델을 사용한 비탄성 좌굴 강도
  3.2 EC3 재료 모델을 사용한 설계 기준의 좌굴강도와 비탄성 해석 결과의 비교
 4. 좌굴 강도식의 제안과 설계 기준비교
  4.1 좌굴 강도식의 제안
  4.2 좌굴 강도의 비교와 고찰
 5. 결론
 References

• 최현식(계명대학교 건축공학전공) | Choi Hyun-Sik (Dept. of Architectural Engineering, Keimyung University) 교신저자