孙劲峰  时旭东  过镇海
    （清华大学土木工程系  北京 100084）

[提要]  通过三面受热钢筋混凝土梁的荷载试验，给出了截面拉区高温梁和压区高温梁在高温时和降温后的主要受力性能及其比较。试验和分析表明，拉区高温梁在高温时的承载力和刚度比常温梁严重下降，但降温后因钢筋强度复原，梁承载力大部分可以恢复；而压区高温梁在高温时和降温后的极限承载力接近，且比常温梁下降有限。
[关键词]  钢筋混凝土梁  高温时  降温后  极限承载力  变形

The behaviors at elevating temperature and after cooling are investigated and compared for reinforced concrete beams heated t0 800C on their three surfaces. The regularities of failure mode, ultimate bending moment and deformation of the beams are analyzed. It is shown that the behavior of beams heated on the tensile zone is damaged heavily at elevating temperature, but it recovered after cooling. The beams heated on compressive zone is slightly damaged at elevating temperature and after cooling.
Keywords:  reinforced concrete beams; elevated temperature; after cooling; ultimate bending moment; deformation