第四章-水平荷载作用下及框架内力分析.doc

此文档收集于网络，如有侵权，请联系网站删除第四章 水平荷载作用下的框架内力分析 4.1梁的线刚度：在计算梁的线刚度时，考虑楼板对梁刚度有利影响,认为翼缘参加工作,为简化计算，先按矩形截面计算惯性矩，然后乘以一个增大系数。现浇钢筋砼梁：边框架梁=1.5I0 中框架梁=2I0柱、梁均采用30混凝土 ，C3.0107 kN/mI0=1/12bh3(m4) KB单位：KNm框架梁线刚度计算部位截面（m）高度（m）截面惯性矩I0 (m4)边框架中框架I=1.5I0(m4)KB=EI/l(kn.m)I=1.5I0 m4)KB=EI/l(kn.m)边框架0.30.77.28.5710-312.8610-3535831.7110-2712500中框架0.30.52.73.1310-34.6910-3469000.6310-263000边框架0.30.77.28.5710-312.8610-3535831.7110-2712504.2 框架柱侧移刚度计算1.柱线刚度：柱采用C30混凝土，首层高度4.43m,2-5层3.6m；柱截面：各层600 mm600mm 则 I0=1/12bh3=10.810-3m4; KC=EI/h 2.柱的侧移刚度D：一般层： = D=首层： = D=部位截面(m)层高(m)惯性矩(m4)Ic=EI/h(104)边框架边柱C1边框架中柱C2K1Dc1K2Dc25层0.63.610.810-390.60.23191671.120.36300004层0.63.610.810-390.60.23191671.120.36300003层0.63.610.810-390.60.23191671.120.36300002层0.63.610.810-390.60.23191671.120.36300001层0.64.4310.810-37.31380.730.45201251.370.5530000部位中框架边柱C1中框架中柱C2各层各柱刚度层间刚度K3Dc3K4Dc4Dc1Dc2Dc3Dc45层0.80.28233331.490.43358331916743000042333316358331812149904层0.80.28233331.490.43358331916743000052333318358331913274893层0.80.28233331.490.43358331916743000052333318358331913274892层0.80.28233331.490.43358331916743000052333318358331913274891层10.49219141.840.6127280191674245975219141827280191139440层间侧移刚度的验算D1/D2 =1139440/1327489=0.860.7 满足要求 4.3.3水平地震作用分析（底部剪力法）本框架结构符合底部剪力法的适用范围，故采用底部剪力法计算水平地震作用。1. 框架自振周期计算:用能量法计算。用能量法计算的数据过程及其结果见表表5 用能量法计算的数据层次（KN）(KN)（KN/m）(m) 56973.326973.3212149900.0060.110767.184.38410003.2816976.613274890.0130.1041040.3108.20310410.7327387.3313274890.0210.091947.486.21210410.7337798.0613274890.0280.07728.751.01110170.2047968.2611394400.0420.042427.117.942. 考虑七度设防：max=0.08 考虑I组类别 类场地土 Tg=0.35 S因为T1=0.391.4Tg=0.49 S 所以考虑顶部附加水平地震作用底部剪力为：1=(Tg/T1)0.9max=(0.35/0.39)0.90.08=0.073FEk=1Geq=0.0730.8547968.26=2976.43 kN 由公式 Fi=(GiHi/GjHj) FEk(1-n)横向框架顶点位移计算层数HiGiGiHiGiHi/GjHjFiVi518.86973.3213107.620.25744.1744.1415.210003.28152349.950.29863.21607.3311.610410.73121076.790.23684.62291.928.0310410.7383598.160.17501.02797.914.4310170.2045053.990.08238.13036.0剪力分布图：4.3.4.验算框架层间弹性位移角1.层数层间剪力I(kN)层间度i层间侧移ui=Vi/Di层 hi(m)Ui/hie5744.112159900.6110-318.830.3210-441607.313274891.2110-315.230.7910-41/55032291.913274891.7310-311.631.4910-4=0.001822797.913274892.1010-38.032.6210-413036.011394402.6610-34.436.0010-4对于钢筋砼框架结构e=1/550, e e 所以满足规范规定的层间弹性位移的要求。 2.楼层地震剪力的验算 抗震规范要求： 因基本周期小于3.5s，查抗震规范表得验算过程及其结果见表7。表7 楼层地震剪力验算层次（KN）(KN)(KN)结 论56973.326973.320.016111.57744.1满 足410003.2816976.60.016271.631607.3满 足310410.7327387.330.016438.202291.9满 足210410.7337798.060.016604.772797.9满 足110170.2047968.260.016767.493036.0满 足4.3.5水平地震作用下框架柱剪力和弯矩计算（D值法：取横向中框架计算）1.柱剪力 Vik=D/D Vi ， 柱弯矩 M下=VikYi ，M上=Vik（1-Yi）hi2.反弯点高度h=(y0+y1+y2+y3) h y=y0+y1+y2+y3h反弯点到柱下端质点的距离，即反弯点高度y0标准反弯点高度比y1为上、下层梁线刚度比变化修正值y2为上层层高变化修正值y3为下层层高修正值根据框架总层数m,该柱所在层数n和梁柱线刚度比值K确定，并由内插法根据K值确定。边柱（中框）层h(m)y0y1y2y3Y53.60.790.30000.343.60.790.40000.433.60.790.450000.4523.60.790.050000.0514.431.790.650000.65中柱（中框）层h(m)y0Y1y2Y3y53.61.490.3750000.37543.61.490.4250000.42533.61.490.4750000.47523.61.490.50000.514.61.840.5660000.5663.边柱弯矩计算层HDDD/DViVikKYM下M上53.61214990233330.019744.114.140.790.315.2735.6343.61327489233330.0181607.328.930.790.441.6662.4933.61327489233330.0182291.941.250.790.4566.8381.6823.61327489233330.0182797.950.360.790.590.6590.6514.431139440219140.0193036.057.680.970.65166.0989.434.中柱弯矩计算：层HDDD/DViVikkYM下M上53.61214990358330.029744.121.581.490.37529.1348.5643.61327489358330.0271607.343.401.490.42566.4089.8433.61327489358330.0272291.961.881.490.475105.81116.9523.61327489358330.0272797.975.541.490.5135.97135.9714.431139440272800.0243036.072.861.840.566182.69140.08计算过程 （1）（2）;（3）4.3.6地震作用下框架梁端剪力和柱轴力标准植计算过程：根据节点平衡由柱端弯矩求得梁轴线处弯矩Mc= M右+ M左= M上+ M下； M右(左梁)= 1Mc M左(右梁)= 2Mc求得 边跨 1=1 2=1 中跨 1=0.531 2=0.469楼层AB跨梁端剪力BC跨梁端剪力柱轴力LM左M右VELM左M右VE边柱中柱57.235.6325.798.532.722.7722.7716.878.538.3447.277.7663