국제초고층학회논문집 (International Journal of High-Rise Buildings)

  • 제7권4호
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  • Pages.287-298
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  • 2018
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  • 2234-7224(pISSN)
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  • 2288-9930(eISSN)
한국초고층도시건축학회 (Council on Tall Building and Urban Habitat Korea)
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Fire Resistance Studies on High Strength Steel Structures

  • Wang, Wei-Yong (School of Civil Engineering, Chongqing University) ;
  • Xia, Yue (School of Civil Engineering, Chongqing University) ;
  • Li, Guo-Qiang (State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University)
  • 발행 : 2018.12.01
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초록

High strength steels have been widely applied in recent years due to high strength and good working performance. When subjected to fire conditions, the strength and elastic modulus of high strength steels deteriorate significantly and hence the load bearing capacity of structures reduces at elevated temperatures. The reduction factors of mechanical properties of high strength steels are quite different from mild steels. Therefore, the fire design methods deduced from mild steel structures are not applicable to high strength steel structures. In recent ten years, the first author of this paper has carried out a lot of fundamental research on fire behavior of high strength steels and structures. Summary of these research is presented in this paper, including mechanical properties of high strength steels at elevated temperature and after fire exposure, creep response of high strength steels at elevated temperature, residual stresses of welded high strength steel member after fire exposure, fire resistance of high strength steel columns, fire resistance of high strength steel beams, local buckling of high strength steel members, and residual strength of high strength steel columns after fire exposure. The results show that the mechanical properties of high strength steel in fire condition and the corresponding fire resistance of high strength steel structures are different from those of mild steel and structures, and the fire design methods recommended in current design codes are not applicable to high strength steel structures.

키워드

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Figure 1. Comparison of mechanical properties of test results with codes

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Figure 2. Comparison of mechanical properties of high strength steels after fire exposure.

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Figure 3. Typical creep strain-time curves of Q460 steel at various stress.

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Figure 4. Typical creep strain-time curves of Q690 steel at various stress.

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Figure 5. Specimens and dimensions.

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Figure 6. Reduction factor of residual stress after fire exposure.

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Figure 7. Comparison of stability coefficient and critical temperature.

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Figure 8. Axial displacements of test specimens.

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Figure 9. Failure modes in test specimens.

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Figure 10. Dimensions of original and equivalent cross sections of the steel beam.

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Figure 11. Finite element model of steel beam.

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Figure 12. Axial displacement-load curves of Q460 steel columns.

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Figure 13. Buckling first occurs at flange.

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Figure 14. Buckling first occurs at web.

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Figure 15. Photos of specimens.

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Figure 16. Temperature history of the specimens.

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Figure 17. Load-deflection curves.

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Figure 18. Load-axial displacement curves.

Table 1. Coefficients of a, b and c in Fields and Fields creep model for Q460 steel

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Table 2. Parameters of the specimens

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Table 3. Comparison of critical temperature of high strength steel beams

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참고문헌

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