Fire tests on unbonded post-tensioned one-way concrete slabs
Fire tests on unbonded post-tensioned one-way concrete slabs
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DOI：
10.1680/macr.2008.00005
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发表时间：
2009-02
影响因子：
2.7
通讯作者：
C. Bailey;E. Ellobody
中科院分区：
文献类型：
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作者：
C. Bailey;E. Ellobody
本文介绍了对单向无粘结预应力混凝土楼板进行的四次火灾试验结果。在环境温度下，在具有相同几何形状和钢筋束钢筋的板上进行两次额外试验，直至失效，结果增加了高温试验。火灾试验突出了使用石灰石和泰晤士河砾石骨料之间的不同结构响应和不同的约束条件，纵向热膨胀。结果表明，与泰晤士河砾石骨料板有更高的挠度相比，石灰石骨料板。约束板有较低的垂直挠度相比，相当于无约束板。在所有火灾试验中，由于在相对较低的钢筋束温度下的热应力，直接与钢筋束成直线和平行的裂纹发生，这在环境试验中没有观察到。在一个火灾试验中，这是采取整体倒塌，它表明，钢筋束钢筋的强度折减系数，目前使用的欧洲设计规范是保守的。测试数据，包括钢筋束应变，垂直和水平位移和温度通过板，将允许验证开发的计算机模型，以预测火灾条件下的无粘结板的行为。
This paper presents the results from four fire tests carried out on one-way spanning unbonded post-tensioned concrete floor slabs. The elevated temperature tests are augmented with the results from two additional tests carried out to failure, on slabs with identical geometry and tendon reinforcement, at ambient temperature. The fire tests highlighted the different structural response between using limestone and Thames gravel aggregates and different restraint conditions to longitudinal thermal expansion. It is shown that slabs with Thames gravel aggregates have a much higher deflection compared to slabs with limestone aggregates. The restrained slabs had lower vertical deflection compared to the equivalent unrestrained slabs. In all the fire tests, cracks directly inline and parallel to the tendons occurred owing to thermal stresses at relatively low tendon temperatures, which were not observed in the ambient tests. In one fire test, which was taken to overall collapse, it was shown that the strength reduction factors for tendon reinforcement currently used in the European design codes is conservative. The test data, comprising tendon strains, vertical and horizontal displacements and temperatures through the slab, will allow validation of developed computer models to predict the behaviour of unbonded slabs under fire conditions.