Structural performance of a post-tensioned concrete floor during horizontally travelling fires
Structural performance of a post-tensioned concrete floor during horizontally travelling fires
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DOI：
10.1016/j.engstruct.2011.02.024
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发表时间：
2011-06
影响因子：
5.5
通讯作者：
E. Ellobody;C. Bailey
中科院分区：
文献类型：
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作者：
E. Ellobody;C. Bailey
本文重点介绍了有粘结后张法混凝土楼板的结构性能，受到火灾的水平传播之间的区域内的楼板。作者以前分析的基础上单向跨越粘结后张混凝土板带的实验和数值研究的楼板。在以前的研究中，开发了一个非线性有限元模型的地板，考虑了地板的组件，组件之间的接口，不同的自然火灾的严重程度，不同的应用静态负载在火灾和不同的约束条件的机械和热材料的非线性。以前的研究强调了调查整个建筑行为的重要性，并提供了一个有用的洞察整个楼板的温度分布，故障模式，与当前的设计规则和时间位移行为的地板在火灾条件下的比较。本文扩展了以往的研究，并使用经过验证的有限元模型来研究不同的水平火灾场景之间的区域和不同的区域间的时间延迟来表示火灾行进时间。预测了在行进火灾作用下楼板不同位置的时温分布。此外，还预测了楼板不同位置的时间-挠度和时间-轴向位移关系。目前的研究表明，水平移动的火灾场景和区域间的时间延迟影响的时间偏转行为相当大。区域之间的加热/冷却方案的变化导致了循环偏转模式，这在设计后张混凝土楼板防火时以前没有考虑过。基于对结果的分析，它表明，最坏的情况下，在地板中的一个给定点的最大垂直挠度或最大残余挠度，可能会发生在均匀火灾或移动火灾的假设。因此，建议设计师应考虑使用各种移动火的地板的完整性。
This paper highlights the structural performance of a bonded post-tensioned concrete floor subject to fires that travel horizontally between zones within the floorplate. The floorplate was previously analysed by the authors based on experimental and numerical investigations on one-way spanning bonded post-tensioned concrete slab strips. In the previous studies, a nonlinear finite element model was developed for the floor that considered the mechanical and thermal material nonlinearities of the floor’s components, interfaces between the components, different natural fire severities, different applied static load during the fire and different restraint conditions. The previous studies highlighted the importance of investigating the whole-building behaviour and provided a useful insight into the temperature distribution throughout the floor slab, failure modes, comparisons with current design rules and time–displacement behaviour of the floor under fire conditions. This paper extends the previous studies and uses the validated finite element model to investigate different horizontal travelling fire scenarios between zones and different inter-zone time delays to represent fire travelling time. The time–temperature distribution throughout the floor slab was predicted at different locations in the floor subject to travelling fires. Furthermore, the time–deflection and time–axial displacement relationships were predicted at different locations in the floor. The current study has shown that horizontally travelling fire scenarios and the inter-zone time delay affect the time–deflection behaviour considerably. The change in heating/cooling scenarios between zones has resulted in a cyclic deflection pattern, which has previously not been considered when designing post-tensioned concrete floors against fire. Based on the analysis of the results presented, it is shown that the worst case in terms of maximum vertical defection or maximum residual deflection, at a given point in the floorplate, could occur either under the assumption of a uniform fire or a travelling fire. It is therefore recommended that designers should consider the integrity of floorplates using various travelling fires.