李易, 陆新征, 叶列平, 任爱珠. 混凝土框架结构火灾连续倒塌数值分析模型[J]. 工程力学, 2012, 29(4): 96-103,. DOI: 10.6052/j.issn.1000-4750.2010.06.0397
引用本文: 李易, 陆新征, 叶列平, 任爱珠. 混凝土框架结构火灾连续倒塌数值分析模型[J]. 工程力学, 2012, 29(4): 96-103,. DOI: 10.6052/j.issn.1000-4750.2010.06.0397
LI Yi, LU Xin-zheng, YE Lie-ping, REN Ai-zhu. NUMERCIAL MODELS OF FIRE INDUCED PROGRESSIVE COLLAPSE ANALYSIS FOR REINFORCED CONCRETE FRAME STRUCTURES[J]. Engineering Mechanics, 2012, 29(4): 96-103,. DOI: 10.6052/j.issn.1000-4750.2010.06.0397
Citation: LI Yi, LU Xin-zheng, YE Lie-ping, REN Ai-zhu. NUMERCIAL MODELS OF FIRE INDUCED PROGRESSIVE COLLAPSE ANALYSIS FOR REINFORCED CONCRETE FRAME STRUCTURES[J]. Engineering Mechanics, 2012, 29(4): 96-103,. DOI: 10.6052/j.issn.1000-4750.2010.06.0397

混凝土框架结构火灾连续倒塌数值分析模型

NUMERCIAL MODELS OF FIRE INDUCED PROGRESSIVE COLLAPSE ANALYSIS FOR REINFORCED CONCRETE FRAME STRUCTURES

  • 摘要: 连续倒塌是整体结构的力学行为,为了研究火灾作用下混凝土框架结构整体抗倒塌性能,建立了用于分析钢筋混凝土构件火灾反应的杆系纤维梁模型和板构件的分层壳模型。在构件层次,模型将各积分点的截面划分为若干纤维(层),纤维(层)被赋予不同的材料属性以考虑钢筋和混凝土的贡献,并通过平截面假定来定义构件变形和纤维(层)应变之间的协调关系;在材料层次,模型将温度-应力路径离散为若干加载步,然后在每个加载步内计算纤维(层)在温度和应力耦合作用下的各种应变分量。通过与一系列试验对比,说明了该模型在模拟混凝土梁、柱和楼板时的准确性和高效性。为了模拟整体结构倒塌过程中的不连续位移场,在模型中引入了构件破坏准则和单元生死技术,可以考虑构件破坏造成的内力重分布对整体结构力学响应的影响。最后,通过一个整体框架结构的火灾倒塌模拟,分析其连续倒塌过程和机理。

     

    Abstract: Progressive collapse is the global behavior of the whole structural system. In order to investigate the fire induced progressive collapse of reinforced concrete (RC) frame structures, a fiber beam model for RC beam and column and a multilayer shell model for RC slab are established. In elemental-scale, the sections at integration points are divided into some fibers or layers. Different material properties are assigned with various fibers and layers to consider the contribution of steel reinforcement and concrete. The relationship between the deformations of elements and the strains of fibers or layers is defined according to the assumption that plane section remains plane. For materials, temperature-stress loading path is discretized into sub-increments. The various strains of fibers or layers, induced by coupled actions of temperature and stresses, are calculated within each sub-increment. The accuracy and efficiency of the models in simulating the behaviors of RC beams, columns and slabs in fire are validated through a series of fire tests. In order to simulate the discontinuous displacement field during the procedure of structure collapse, the failure criterion and the deactivation of the structural elements are introduced to the model. Therefore, the influence of internal force redistribution induced by element failure on the mechanical response of the whole structure is taken into consideration. At last, a frame structure is analyzed to study the failure mechanism of its fire induced collapse via the proposed numerical models.

     

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