Resumen:
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[EN] Cost-effective solutions provided by composite construction are gaining popularity which, in turn, promotes the
appearance on the market of new types of composite sections that allow not only to take advantage of the ...[+]
[EN] Cost-effective solutions provided by composite construction are gaining popularity which, in turn, promotes the
appearance on the market of new types of composite sections that allow not only to take advantage of the synergy of steel and
concrete working together at room temperature, but also to improve their behaviour at high temperatures. When combined with
high performance materials, significant load-bearing capacities can be achieved even with reduced cross-sectional dimensions.
Steel-reinforced concrete-filled steel tubular (SR-CFST) columns are one of these innovative composite sections, where an open
steel profile is embedded into a CFST section. Besides the renowned benefits of these typologies at room temperature, the fire
protection offered by the surrounding concrete to the inner steel profile, gives them an enhanced fire performance which delays
its loss of mechanical capacity in a fire scenario. The experimental evidence on the fire behaviour of SR-CFST columns is still
scarce, particularly when combined with high performance materials. However, it is being much needed for the development of
specific design provisions that consider the use of the inner steel profile in CFST columns. In this work, a new experimental
program on the thermo-mechanical behaviour of SR-CFST columns is presented to extend the available experimental database.
Ten SR-CFST stub columns, with circular and square geometries, combining high strength steel and concrete were tested. It was
seen that the circular specimens reached higher failure times than the square columns, with the failure time increasing both when
high strength steel was used at the embedded steel profile and high strength concrete was used as infill. Finally, different
proposals for the reduction coefficients of high performance materials were assessed in the prediction of the cross-sectional fire
resistance of the SR-CFST columns.
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Agradecimientos:
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The authors would like to express their sincere gratitude for the help provided through the Grant PID2019-105908RB-I00 and for the first author's pre-doctoral contract through the Grant PRE2020-093106 funded by ...[+]
The authors would like to express their sincere gratitude for the help provided through the Grant PID2019-105908RB-I00 and for the first author's pre-doctoral contract through the Grant PRE2020-093106 funded by MCIN/AEI/10.13039/501100011033 and by "ESF Investing in your future". The authors are deeply grateful to Dr Enrique Serra for his help in preparing the test specimens, and to Dr Andres Lapuebla-Ferri and Dr David Pons for their help in conducting the material tests. Finally, the authors would like to acknowledge the funding for open access charge from CRUE-Universitat Politecnica de Valencia.
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