高温下钢筋混凝土简支梁的抗火性能

对2根钢筋混凝土梁开展高温试验研究,采用合理的材料热工性能和热-力耦合本构关系,应用ABAQUS有限元软件对其温度场和结构变形性能进行三维实体有限元分析,温度场和结构变形性能计算结果与试验结果符合较好.在试验验证的基础上,开展有限元参数分析,探讨保护层厚度及荷载水平对钢筋混凝土简支梁抗火性能的影响.结果表明,钢筋混凝土简支梁的保护层越厚,受拉主筋升温越慢,构件变形延缓,耐火极限增大;荷载水平越大,耐火极限越小.

Fire Resistance of Simple Supported Reinforced Concrete Beams Under High Temperature

The experiment of two reinforced concrete beams under high temperatures were conducted. A reasonable material thermal performance and thermal-mechanical coupled constitutive relation were adopted in the 3D finite element model by ABAQUS to analyze the performance of reinforced concrete beams. Temperature field and deformation results agree well with the test results. Based on experiment verifications， the effects of protective layer thickness and the load level on the fire resistance of concrete beams were studied by using finite element parametric analysis. Results showed that the thicker the concrete cover is， the slower the temperature rise of tensile reinforcement is， and the smaller the deflection of speciment is， which means that the fire resistance of reinforced concrete beam is longer. Correspondingly， the fire resistance gets shorter when load level is increased.