- 摘 要
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韋 鋒 楊 紅 白紹良 （重慶大學(xué)土木工程學(xué)院 400045）王 珍 （華東建筑設(shè)計研究院 上海 200002）
[提要] 以我國8度區(qū)（設(shè)計基本地震加速度0.2g）二級抗震鋼筋混凝土框架結(jié)構(gòu)為例，選取底層柱底截面的三檔彎矩增強系數(shù)與上部各層柱端抗彎能力的兩檔增強措施相組合，設(shè)計出6榀典型平面框架；再以采用單分量模型和改進武田滯回模型的桿系結(jié)構(gòu)彈塑性動力反應(yīng)分析程序PL-AFJD對這些框架依次進行了相當(dāng)于罕遇地震水準(zhǔn)的4條地面運動輸入下的地震反應(yīng)分析。分析結(jié)果初步表明，要使結(jié)構(gòu)全面滿足抗震設(shè)計要求，底層柱下端截面彎矩增強系數(shù)的取值應(yīng)與上部各層柱的增強措施相匹配；修訂后規(guī)范8度區(qū)二級抗震等級框架上部各層柱的增強措施與修訂前相比雖已有提高，但提高幅度尚嫌不足；底層柱底增強系數(shù)也宜在修訂后規(guī)范取值1.25的基礎(chǔ)上適度提高。
[關(guān)鍵詞] 鋼筋混凝土 框架 抗震設(shè)計 底層柱底彎矩增強系數(shù)Six RC frames of seismic grade 2 in earthquake intensity 8 regions were designed by combination of three moment amplification coefficients at the bottom sections of columns in the ground floor and two different amplification methods of columns in upper stories. By means of nonlinear dynamic analysis program PL-AFJD, the seismic response analysis under major earthquake was carried out by inputting four ground motions. The results indicate that the moment amplification coefficient at the bottom section of columns in the ground floor should be compatible to that of the upper stories; for the RC frames of seismic grade 2 in earthquake intensity 8 regions, the amplification method of columns in upper stories is not sufficient in the revised code, and the moment amplification coefficient at the botrom section of columns is advised to be increased greater than the current value of l .25.
Keywords: reinforced concrete; frame; seismic design; moment amplification coefficient; bottom section; columns
