段泊池, 杨冬冬, 刘发起, 杨华. 带有防火保护的圆钢管约束钢筋混凝土柱抗火性能分析与设计[J]. 工程力学. DOI: 10.6052/j.issn.1000-4750.2022.05.0470
引用本文: 段泊池, 杨冬冬, 刘发起, 杨华. 带有防火保护的圆钢管约束钢筋混凝土柱抗火性能分析与设计[J]. 工程力学. DOI: 10.6052/j.issn.1000-4750.2022.05.0470
DUAN Bo-chi, YANG Dong-dong, LIU Fa-qi, YANG Hua. ANALYSIS AND DESIGN ON FIRE PERFORMANCE OF CIRCULAR STEEL TUBE CONFINED REINFORCED CONCRETE COLUMNS WITH FIRE PROTECTION[J]. Engineering Mechanics. DOI: 10.6052/j.issn.1000-4750.2022.05.0470
Citation: DUAN Bo-chi, YANG Dong-dong, LIU Fa-qi, YANG Hua. ANALYSIS AND DESIGN ON FIRE PERFORMANCE OF CIRCULAR STEEL TUBE CONFINED REINFORCED CONCRETE COLUMNS WITH FIRE PROTECTION[J]. Engineering Mechanics. DOI: 10.6052/j.issn.1000-4750.2022.05.0470

带有防火保护的圆钢管约束钢筋混凝土柱抗火性能分析与设计

ANALYSIS AND DESIGN ON FIRE PERFORMANCE OF CIRCULAR STEEL TUBE CONFINED REINFORCED CONCRETE COLUMNS WITH FIRE PROTECTION

  • 摘要: 抗火性能是圆钢管约束钢筋混凝土柱设计时的关键问题之一,尽管目前相关研究已逐渐完善,但带有防火保护条件下该类构件的抗火性能研究与设计仍不充分,已有的行业标准中构件高温稳定承载力公式未与常温公式相连续,且其中的防火保护层设计公式不具有明确的物理意义。基于ABAQUS软件,本文开展了带有防火保护圆钢管约束钢筋混凝土柱在ISO 834标准火灾作用下温度场和耐火极限的有限元分析,研究了荷载比、截面尺寸、长细比、防火保护层厚度等关键参数对构件耐火极限的影响规律,并提出了钢管温度、钢筋温度以及混凝土等效温度的简化计算公式。结果表明随着防火保护层厚度的增大,构件的耐火极限近似线性增大。基于系统性参数分析,提出了带有防火保护圆钢管约束钢筋混凝土柱高温下截面承载力和稳定承载力设计公式,以用于确定构件达到不同耐火极限所需的防火保护层厚度,该方法保持了与现行标准中常温承载力计算公式的连续性。

     

    Abstract: Structural fire safety design is one of the key issues of circular steel tube confined reinforced concrete (STCRC) columns. Although an increasing number of studies are being conducted on the fire behaviours of circular STCRC columns, research and design on the fire performance of such columns with fire protection are still insufficient. The existing design method of high-temperature buckling resistance in current industry standard is not consistent with the corresponding method at ambient temperature. The design formulae for fire-protected circular STCRC columns in this standard are of no clear physical meaning. Using the ABAQUS software, this paper presents numerical simulations of the thermal distribution and fire resistance of circular STCRC columns with fire protection under the ISO 834 standard fire condition. The effects of key parameters such as load ratio, cross-sectional dimension, slenderness ratio and thickness of protection on the fire resistance of circular STCRC columns are studied. Practical formulae are proposed to calculate the temperature profiles of the steel tube, rebars and concrete core. The results show that with the increase of the fire protection thickness, the fire resistance of the column increases approximately linearly. Based on extensive parametric studies, design methods are developed for determining the compressive resistance and buckling resistance of protected circular STCRC columns at elevated temperatures, which could be used to calculate the fire protection thickness required for circular STCRC columns to reach different fire resistance rates. This method remains consistent with the design equations of ambient-temperature load-bearing capacity in the current standard.

     

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