This article presents a numerical investigation on the mechanical behaviours, such as the fire resistance, the moment redistribution and the failure mode, of continuous reinforced concrete beams with two spans and three spans under the standard fire of ISO-834. Firstly, a 3D finite element model was established and validated against the fire test beam. Secondly, the three stages associated with the fire time of fire behaviour for the continuous reinforced concrete beams were divided and explained. An index of the moment redistribution amplitude was modified and used to evaluate the fire performance of continuous reinforced concrete beams. A series of parametric analyses for continuous reinforced concrete beams with two spans were conducted in order to investigate the influence of some parameters such as the load ratio, the load position, the support condition and the sectional size. Finally, the distributions of the vertical deflection and the plastic hinge within beam spans and the failure modes for continuous reinforced concrete beams with three spans under local fire conditions were discussed emphatically.

本文对 ISO-834 标准火灾下两跨和三跨连续钢筋混凝土梁的力学行为进行了数值研究，如耐火性能、弯矩再分配和破坏模式。首先，建立了一个 3D 有限元模型，并针对防火测试梁进行了验证。其次，对连续钢筋混凝土梁的火灾行为与火灾时间相关的三个阶段进行了划分和说明。修正了弯矩重分布幅度的指标，用于评价连续钢筋混凝土梁的防火性能。对两跨连续钢筋混凝土梁进行了一系列参数分析，以研究荷载比、荷载位置、支撑条件和截面尺寸。最后重点讨论了梁跨内竖向挠​​度和塑性铰的分布以及局部火灾条件下三跨连续钢筋混凝土梁的破坏模式。