由于柱纵向集中荷载的作用,对柱产生偏心。在恒荷载和活荷载的作用下的偏心矩如图12,13所示。
图12 竖向恒载引起的偏心弯矩
图13 竖向活载引起的偏心弯矩
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4.5.1 梁柱端的弯矩计算
梁端柱端弯矩采用弯矩分配法计算。计算步骤为:
(1) 将原框架分为5个敞口单元,除底层柱外的其于各层柱的相对线刚度乘
以0.9。
(2) 用弯矩分配法计算每一个敞口单元的杆端弯矩,底层柱的传递系数为
0.5,其余各层柱的传递系数为1/3。
将分层法所得到的弯矩图叠加,并将节点不平衡弯矩进行再分配。 梁端固定弯矩计算: 恒载: 屋面:MgAW,BW??121gl???23.04?6.32??76.20kN?m 1212gBW,AW M MgBW,CW?76.20kN?m
??121gl???13.382?2.12??3.72kN?m 1212gCW,BW M MgCW,DW?3.72kN?m
??121gl???23.04?6.32??76.20kN?m 1212gDW,CW M 楼面:MgAb,Bb?76.20kN?m
??121gl???31.496?6.32??104.173kN?m 1212gBb,Ab M MgBb,Ab?104.73kN?m
??121gl???23.09?2.12??8.49kN?m 1212gBb,Cb M MgCb,Db?8.49kN?m
??104.173kN?m
gDb,Cb M活载: 屋面: MqAw,Bw?104.73kN?m
??q121ql???7.88?6.32??26.06kN?m 1212 MBW,AW?26.06kN?m
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MqBW,CW??121ql???4.2?2.12??1.54kN?m 1212qCW,BW M MqCW,DW?1.54kN?m
??121ql???7.88?6.32??26.06kN?m 1212qCW,DW M
屋面: MqAb,Bb?26.06kN?m
??121ql???7.88?6.32??26.06kN?m 1212qBb,Ab M MqBb,Cb?26.06kN?m
??121ql???5.25?2.12??1.93kN?m 1212qCb,Bb M MqCb,Db?1.93kN?m
??121ql???7.88?6.32??26.06kN?m 1212qDb,Cb M?26.06kN?m
分层法计算见图14、15、16。
下柱左梁0.4130.587-11.64-76.2036.2851.56-17.927.400.4532.4910.8310.52-1.090.64-32.49右梁下柱左梁0.4120.2900.29876.20-11.26-3.7225.78-35.84-25.23-25.935.26-2.17-1.53-1.57-1.8625.931.5725.6469.23-38.02-31.22-12.6733 / 144
69.2332.4932.4931.2238.0225.6410.8312.67图14 顶层弯矩分配及弯矩图
12.99-7.73右梁上柱下柱0.2920.2920.415-12.82-104.1734.1634.1648.55-15.914.650.1538.968.714.650.1526.146.60-0.530.22-65.24左梁上柱下柱0.3190.2250.225104.17-20.2024.28-31.82-22.45-22.453.30-1.05-0.74-0.74左梁0.231-8.49-23.04-0.76-4.2423.040.7619.5798.88-23.19-43.39-32.29-14.46
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12.997.7398.8865.2426.1438.9623.1919.5732.2943.398.7114.46
图15 三-二层弯矩分配及弯矩图
13.548.02右梁上柱下柱0.3030.2680.430-12.82-104.7135.4531.3550.31-16.515.000.1840.6311.564.420.1623.117.10-0.580.25-63.60左梁上柱下柱0.3280.2310.204104.17-20.225.15-33.01-23.25-20.533.55-1.16-0.82-0.72左梁0.237-8.49-23.85-0.84-4.2423.850.8420.4698.70-24.07-41.45-35.1820.73
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