中文摘要：

通过钢筋混凝土框架的火灾全过程分析，初步探讨高温下钢筋混凝土框架的内力重分布规律。推导建立了高温下钢筋混凝土的简化梁单元模型，编制了钢筋混凝土框架高温反应的全过程分析程序，程序的正确性得到了其他学者试验结果的验证。选取1榀单层3跨的钢筋混凝土框架，针对不同梁柱线刚度比和不同柱子轴压比的情况分别进行了该框架的高温反应分析，考察了部分控制截面的内力重分布规律。研究结果表明，高温下框架结构产生剧烈的内力重分布，其中框架梁的轴力和梁端弯矩变化尤为剧烈，成为影响框架结构其他控制截面内力变化的主要因素之一；随着梁柱线刚度比和柱子轴压比增大，框架梁的轴向压力逐渐加大。在结构层次上开展钢筋混凝土框架的耐火研究，可更为全面科学地把握不同构件的最不利受力状况。

英文摘要：

The redistribution of internal forces in reinforced concrete frames under high temperature is primarily studied. For the study, a simplified beam-element-model for reinforced concrete is employed. An analytical procedure for reinforced concrete frames under high temperature is proposed and the procedure is validated by using the test results found in the literature. A three-span one-storey reinforced concrete frame is selected for fire response analysis. Different line-stiffness-ratios of beam to column and different axial load ratios of column are considered in the analysis. The redistribution of internal forces at some key sections in the frame is discussed in the paper. The analysis results indicate： （1） redistribution of internal forces in the frame subjected to high temperature is quite significant; （2） redistribution of the axial force of the beam and the redistribution of the bending moment at the end of the beam are especially significant, and these are the most important causes of the variations of the internal forces in other sections; and （3） with an increase in the line-stiffness-ratio of beam to column and in the axial load ratio, the axial force of the beam increases accordingly.