Fire-Resistant Design Methods of U-Shaped Steel-Concrete Composite Beams under Distributed Loading

Weiqi Yang, Yuanlong Yang, Xuan Wei, Faqi Liu, Yohchia Frank Chen

Research output: Contribution to journalArticlepeer-review


The U-shaped steel-concrete composite beam (USCB) has the superiority of good stiffness, high load-bearing capacity, and good fire performance. In this paper, the numerical simulation and theoretical derivation were conducted for the thermal transfer and fire-resistant research of USCBs. Four fire tests on USCB specimens under the current standard temperature rising curve were used to validate the fire design method. The temperature field models and fire-resistance models were set up to research heat-transfer and structural mechanisms, and the analysis showed that the fire condition of different concrete sections was different in the USCBs, and the internal force redistribution happened in the composite beam. Then, the parametric analysis shows that the load ratio, the diameter of fire-resistance reinforcement, and the thickness of the fire protection layer have significant effects on the fire performance. The temperature calculation methods of U-shaped steel, different concrete sections, and fire-resistant reinforcement are proposed based on the conducted research. Moreover, a flexural bearing capacity calculation method for the USCB under the standard temperature rise curve is proposed allowing for the influence of material strength reduction under high temperatures, which can also be used to calculate the fire resistance. Finally, the calculation tables for the fire protection layer thickness and the corresponding design method are proposed based on the delaying temperature mechanism.

Original languageEnglish (US)
Article number04023172
JournalJournal of Structural Engineering (United States)
Issue number12
StatePublished - Dec 1 2023

All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Building and Construction
  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering

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