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    孫勁峰  時(shí)旭東  過鎮(zhèn)海
    （清華大學(xué)土木工程系  北京 100084）

[提要]  通過三面受熱鋼筋混凝土梁的荷載試驗(yàn)，給出了截面拉區(qū)高溫梁和壓區(qū)高溫梁在高溫時(shí)和降溫后的主要受力性能及其比較。試驗(yàn)和分析表明，拉區(qū)高溫梁在高溫時(shí)的承載力和剛度比常溫梁嚴(yán)重下降，但降溫后因鋼筋強(qiáng)度復(fù)原，梁承載力大部分可以恢復(fù)；而壓區(qū)高溫梁在高溫時(shí)和降溫后的極限承載力接近，且比常溫梁下降有限。
[關(guān)鍵詞]  鋼筋混凝土梁  高溫時(shí)  降溫后  極限承載力  變形

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