Fire Behavior of Timber-Encased Steel Composite Structures: A Meta-Analytic Review of Experimental Findings and Design Implications

Girmay Mengesha Aznaw

doi:doi:10.11648/j.ri.20250101.19

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Fire Behavior of Timber-Encased Steel Composite Structures: A Meta-Analytic Review of Experimental Findings and Design Implications

Girmay Mengesha Aznaw^*

Published in Research and Innovation (Volume 1, Issue 1)

Received: 29 October 2025 Accepted: 7 November 2025 Published: 19 December 2025

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Abstract

Timber-encased steel composite (TESC) systems have emerged as a promising structural solution combining strength, sustainability, and enhanced fire performance. This meta-analytic review synthesizes experimental and numerical findings reported between 2020 and 2025 to assess the influence of timber encasement on the fire resistance of steel members. Data from full-scale and small-scale fire tests were statistically aggregated using random-effects models to determine pooled fire resistance and to quantify the effects of parameters such as timber thickness and moisture content. Results show that full timber encasement markedly delays steel heating and improves fire endurance. On average, each additional millimeter of timber cover contributes approximately 1.9 minutes of fire resistance (p < 0.01), with 50 mm encasement achieving roughly one hour of protection under ISO 834 conditions. Moisture within the timber further reduces the rate of temperature rise by absorbing latent heat during evaporation. The study confirms that the insulating and charring behavior of timber functions as an effective passive fire-protection layer, offering an alternative to conventional coatings or boards. Design implications are significant: empirical correlations between cover thickness and fire resistance can inform future fire-design models and code calibrations. Remaining research needs include long-term performance of composite joints and validation under realistic fire scenarios. Overall, the review provides quantitative evidence supporting timber encasement as a viable, sustainable, and code-integral approach for improving the fire safety of composite steel structures.

Published in	Research and Innovation (Volume 1, Issue 1)
DOI	10.11648/j.ri.20250101.19
Page(s)	71-76
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2025. Published by Science Publishing Group

Keywords

Timber-Encased Steel, Fire Performance, Composite Structures, Meta-Analysis, and Structural Design Implications

References

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[2]	Béreyziat, A., Dhima, D., Durif, S., Audebert, M., Bouchaïr, A., & Si Larbi, A. (2024). Fire tests on steel–timber composite beams. Fire Technology, 60(6), 2601–2620. https://doi.org/10.1007/s10694-023-01536-y
[3]	Abdelrahman, M., Khaloian-Sarnaghi, A., & van de Kuilen, J. W. (2025). Fire performance of wood–steel hybrid elements: finite element analysis and experimental validation. Wood Science and Technology, 59(1), Article 23. https://doi.org/10.1007/s00226-024-01628-0
[4]	Nguyen, M. H., Ouldboukhitine, S. E., Durif, S., Saulnier, V., & Bouchair, A. (2023). Passive fire protection of steel profiles using wood. Engineering Structures, 275, 115274. https://doi.org/10.1016/j.engstruct.2022.115274
[5]	van der Aalst, J., & Smith, R. (2019). Fire resistance enhancement in timber-steel composite beams under varying timber cover thicknesses. Journal of Structural Fire Engineering, 10(3), 245–260. https://doi.org/10.1108/JSFE-04-2019-0025
[6]	Zhao, Y., Li, W., & Wang, J. (2020). Experimental and numerical study on the fire behavior of wood–steel hybrid slabs with laminated veneer lumber. Fire Safety Journal, 113, 102972. https://doi.org/10.1016/j.firesaf.2020.102972
[7]	Maläska, T., Alanen, J., Salminen, R., Jokinen, T., & Ranua, P. (2023). Hybrid steel elements with wood cladding for passive fire protection: Experimental testing and FE analysis. Engineering Structures, 290, 116300. https://doi.org/10.1016/j.engstruct.2023.116300
[8]	Johansson, M., & Nguyen, H. T. (2022). Thermal performance of glulam-encased H-section steel beams under standard fire exposure. Journal of Constructional Steel Research, 198, 107512. https://doi.org/10.1016/j.jcsr.2022.107512
[9]	Müller, K., Garcia, L., & Pettersson, A. (2023). Fire resistance of CLT–steel hybrid floor panels: Experimental and numerical evaluation. Fire Safety Journal, 136, 103807. https://doi.org/10.1016/j.firesaf.2023.103807
[10]	Lee, D. J., Kim, S. H., & Park, J. Y. (2024). Fire resistance of box-type timber-encased steel composite columns under axial compression. Construction and Building Materials, 414, 134879. https://doi.org/10.1016/j.conbuildmat.2024.134879
[11]	Costa, R., Silva, F., & Fernandes, M. (2023). Thermal response and charring behavior of glulam-encased RHS beams under standard fire. Fire Technology, 59, 1863–1884. https://doi.org/10.1007/s10694-023-01342-6
[12]	Brown, T., Evans, M., & Clark, D. (2024). Fire performance of composite beam–column joints with laminated timber encasement. Structures, 69, 1085–1102. https://doi.org/10.1016/j.istruc.2024.01.054
[13]	Singh, R., Sharma, P., & Patel, N. (2024). Fire resistance enhancement of laminated veneer timber–steel frame composites using intumescent coatings. Fire Safety Journal, 140, 103920. https://doi.org/10.1016/j.firesaf.2024.103920
[14]	Nguyen, T. H., Tran, Q. M., & Le, P. H. (2025). Fire performance of full-scale timber-encased steel composite wall assemblies. Case Studies in Construction Materials, 23, e02187. https://doi.org/10.1016/j.cscm.2024.e02187
[15]	Sofia Pastori, Enrico Sergio Mazzucchelli, Marita Wallhagen (2022). Hybrid timber-based structures: A state of the art review. Construction and Building Materials 359(12): 129505 https://doi.org/10.1016/j.conbuildmat.2022.129505

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APA Style

Aznaw, G. M. (2025). Fire Behavior of Timber-Encased Steel Composite Structures: A Meta-Analytic Review of Experimental Findings and Design Implications. Research and Innovation, 1(1), 71-76. https://doi.org/10.11648/j.ri.20250101.19

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ACS Style

Aznaw, G. M. Fire Behavior of Timber-Encased Steel Composite Structures: A Meta-Analytic Review of Experimental Findings and Design Implications. Res. Innovation 2025, 1(1), 71-76. doi: 10.11648/j.ri.20250101.19

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AMA Style

Aznaw GM. Fire Behavior of Timber-Encased Steel Composite Structures: A Meta-Analytic Review of Experimental Findings and Design Implications. Res Innovation. 2025;1(1):71-76. doi: 10.11648/j.ri.20250101.19

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@article{10.11648/j.ri.20250101.19,
  author = {Girmay Mengesha Aznaw},
  title = {Fire Behavior of Timber-Encased Steel Composite Structures: A Meta-Analytic Review of Experimental Findings and Design Implications},
  journal = {Research and Innovation},
  volume = {1},
  number = {1},
  pages = {71-76},
  doi = {10.11648/j.ri.20250101.19},
  url = {https://doi.org/10.11648/j.ri.20250101.19},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ri.20250101.19},
  abstract = {Timber-encased steel composite (TESC) systems have emerged as a promising structural solution combining strength, sustainability, and enhanced fire performance. This meta-analytic review synthesizes experimental and numerical findings reported between 2020 and 2025 to assess the influence of timber encasement on the fire resistance of steel members. Data from full-scale and small-scale fire tests were statistically aggregated using random-effects models to determine pooled fire resistance and to quantify the effects of parameters such as timber thickness and moisture content. Results show that full timber encasement markedly delays steel heating and improves fire endurance. On average, each additional millimeter of timber cover contributes approximately 1.9 minutes of fire resistance (p < 0.01), with 50 mm encasement achieving roughly one hour of protection under ISO 834 conditions. Moisture within the timber further reduces the rate of temperature rise by absorbing latent heat during evaporation. The study confirms that the insulating and charring behavior of timber functions as an effective passive fire-protection layer, offering an alternative to conventional coatings or boards. Design implications are significant: empirical correlations between cover thickness and fire resistance can inform future fire-design models and code calibrations. Remaining research needs include long-term performance of composite joints and validation under realistic fire scenarios. Overall, the review provides quantitative evidence supporting timber encasement as a viable, sustainable, and code-integral approach for improving the fire safety of composite steel structures.},
 year = {2025}
}

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TY  - JOUR
T1  - Fire Behavior of Timber-Encased Steel Composite Structures: A Meta-Analytic Review of Experimental Findings and Design Implications
AU  - Girmay Mengesha Aznaw
Y1  - 2025/12/19
PY  - 2025
N1  - https://doi.org/10.11648/j.ri.20250101.19
DO  - 10.11648/j.ri.20250101.19
T2  - Research and Innovation
JF  - Research and Innovation
JO  - Research and Innovation
SP  - 71
EP  - 76
PB  - Science Publishing Group
UR  - https://doi.org/10.11648/j.ri.20250101.19
AB  - Timber-encased steel composite (TESC) systems have emerged as a promising structural solution combining strength, sustainability, and enhanced fire performance. This meta-analytic review synthesizes experimental and numerical findings reported between 2020 and 2025 to assess the influence of timber encasement on the fire resistance of steel members. Data from full-scale and small-scale fire tests were statistically aggregated using random-effects models to determine pooled fire resistance and to quantify the effects of parameters such as timber thickness and moisture content. Results show that full timber encasement markedly delays steel heating and improves fire endurance. On average, each additional millimeter of timber cover contributes approximately 1.9 minutes of fire resistance (p < 0.01), with 50 mm encasement achieving roughly one hour of protection under ISO 834 conditions. Moisture within the timber further reduces the rate of temperature rise by absorbing latent heat during evaporation. The study confirms that the insulating and charring behavior of timber functions as an effective passive fire-protection layer, offering an alternative to conventional coatings or boards. Design implications are significant: empirical correlations between cover thickness and fire resistance can inform future fire-design models and code calibrations. Remaining research needs include long-term performance of composite joints and validation under realistic fire scenarios. Overall, the review provides quantitative evidence supporting timber encasement as a viable, sustainable, and code-integral approach for improving the fire safety of composite steel structures.
VL  - 1
IS  - 1
ER  -

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Author Information

Girmay Mengesha Aznaw

Civil Engineering Department, University of Gondar, Gondar, Ethiopia

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http://orcid.org/0009-0009-7187-6572

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APA Style

Aznaw, G. M. (2025). Fire Behavior of Timber-Encased Steel Composite Structures: A Meta-Analytic Review of Experimental Findings and Design Implications. Research and Innovation, 1(1), 71-76. https://doi.org/10.11648/j.ri.20250101.19

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ACS Style

Aznaw, G. M. Fire Behavior of Timber-Encased Steel Composite Structures: A Meta-Analytic Review of Experimental Findings and Design Implications. Res. Innovation 2025, 1(1), 71-76. doi: 10.11648/j.ri.20250101.19

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AMA Style

Aznaw GM. Fire Behavior of Timber-Encased Steel Composite Structures: A Meta-Analytic Review of Experimental Findings and Design Implications. Res Innovation. 2025;1(1):71-76. doi: 10.11648/j.ri.20250101.19

Copy | Download

@article{10.11648/j.ri.20250101.19,
  author = {Girmay Mengesha Aznaw},
  title = {Fire Behavior of Timber-Encased Steel Composite Structures: A Meta-Analytic Review of Experimental Findings and Design Implications},
  journal = {Research and Innovation},
  volume = {1},
  number = {1},
  pages = {71-76},
  doi = {10.11648/j.ri.20250101.19},
  url = {https://doi.org/10.11648/j.ri.20250101.19},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ri.20250101.19},
  abstract = {Timber-encased steel composite (TESC) systems have emerged as a promising structural solution combining strength, sustainability, and enhanced fire performance. This meta-analytic review synthesizes experimental and numerical findings reported between 2020 and 2025 to assess the influence of timber encasement on the fire resistance of steel members. Data from full-scale and small-scale fire tests were statistically aggregated using random-effects models to determine pooled fire resistance and to quantify the effects of parameters such as timber thickness and moisture content. Results show that full timber encasement markedly delays steel heating and improves fire endurance. On average, each additional millimeter of timber cover contributes approximately 1.9 minutes of fire resistance (p < 0.01), with 50 mm encasement achieving roughly one hour of protection under ISO 834 conditions. Moisture within the timber further reduces the rate of temperature rise by absorbing latent heat during evaporation. The study confirms that the insulating and charring behavior of timber functions as an effective passive fire-protection layer, offering an alternative to conventional coatings or boards. Design implications are significant: empirical correlations between cover thickness and fire resistance can inform future fire-design models and code calibrations. Remaining research needs include long-term performance of composite joints and validation under realistic fire scenarios. Overall, the review provides quantitative evidence supporting timber encasement as a viable, sustainable, and code-integral approach for improving the fire safety of composite steel structures.},
 year = {2025}
}

Copy | Download

TY  - JOUR
T1  - Fire Behavior of Timber-Encased Steel Composite Structures: A Meta-Analytic Review of Experimental Findings and Design Implications
AU  - Girmay Mengesha Aznaw
Y1  - 2025/12/19
PY  - 2025
N1  - https://doi.org/10.11648/j.ri.20250101.19
DO  - 10.11648/j.ri.20250101.19
T2  - Research and Innovation
JF  - Research and Innovation
JO  - Research and Innovation
SP  - 71
EP  - 76
PB  - Science Publishing Group
UR  - https://doi.org/10.11648/j.ri.20250101.19
AB  - Timber-encased steel composite (TESC) systems have emerged as a promising structural solution combining strength, sustainability, and enhanced fire performance. This meta-analytic review synthesizes experimental and numerical findings reported between 2020 and 2025 to assess the influence of timber encasement on the fire resistance of steel members. Data from full-scale and small-scale fire tests were statistically aggregated using random-effects models to determine pooled fire resistance and to quantify the effects of parameters such as timber thickness and moisture content. Results show that full timber encasement markedly delays steel heating and improves fire endurance. On average, each additional millimeter of timber cover contributes approximately 1.9 minutes of fire resistance (p < 0.01), with 50 mm encasement achieving roughly one hour of protection under ISO 834 conditions. Moisture within the timber further reduces the rate of temperature rise by absorbing latent heat during evaporation. The study confirms that the insulating and charring behavior of timber functions as an effective passive fire-protection layer, offering an alternative to conventional coatings or boards. Design implications are significant: empirical correlations between cover thickness and fire resistance can inform future fire-design models and code calibrations. Remaining research needs include long-term performance of composite joints and validation under realistic fire scenarios. Overall, the review provides quantitative evidence supporting timber encasement as a viable, sustainable, and code-integral approach for improving the fire safety of composite steel structures.
VL  - 1
IS  - 1
ER  -

Copy | Download