反弯点法及D值法设计题doc资料

1、反弯点法及D值法设计题土木1204班组员：卢焕然邵明明胡伟卢鼎刘杰张辉周敏题目：试分别用反弯点法和D值法计算下列图1-1所示框架结构的内力(弯矩、剪力、轴力)和水平位移.图中在各杆件旁标出了线刚度,其中i=2600kN?m.图1-1:(1)反弯点法:解：顶层柱反弯点位于柱中点1,底层柱的反弯点位于柱高3儿处,在反弯点处将柱切开,脱离体如图2、图3所示.SlkNl图1-2顶层脱离体:图1-3底层脱离体:(1)求各柱剪力分配系数kkk飞顶层:GDIF20.286223HE30.428223底层:DAFC30.3324EB43240.4(2)计算各柱剪力:FQGDFQIF0.2868kN2.29kN

2、FQHE0.4288kN3.42kNFQADFqcf0.325kN7.5kNQQFqbe0.425kN10kN(3)计算杆端弯矩,以节点E为例说明杆端弯矩的计算杆端弯矩：MehFqhe以3.42kN33m5.64kNm(反弯点位于务222一lR3.62MebFqbe-10kNm12kNm反弯点位于柱品333处计算梁端弯矩时,先求出节点柱端弯矩之和为：MMEHMeb17.64kNm按梁刚度分配：7.84kNm9.8kNm12Med17.642715Mef17.6427图1-4是刚架弯矩图:3.783.7883.783.133.789123.789.812.781824173.782.515.64

3、5.647.8412.78图1-4弯矩图单位kNm：(2)D值法:求各柱的剪力值:12+12K=62.26ac=0.752+6122D=0.75?21.653.32、,1.65八cc“V=?82.166.1,/12+15+12+15-K=92,39ac=0.822+9123D=0.82?2-2.713.322.71V=?83.556.1/15+15K=7.52.27.5ac=0.792+7.5122D=0.79?钎1.743.321.74V=?82.286.112K=43/12+15K=6.754/15二K=530.5+4八.aO=0.75c2+4123D=0.75?2.083.62V=28?

4、257.087.34=0.83c2+6.75124D=0.83?v3.073.623.07-V=?2510.467.340.5+5八7caO=0.79c2+5123D=0.79?,2.193.622.19V=?257.467.34求个柱反弯点高度yh：K=6,y0=0.4512CCI1=1,y1=0,y2=01213=,y3=012y=0.45+0+0=0.45K=9,y0=0.4512+15._八._11=1,yl=0,y2=012+15I3=1,y3=012y=0.45+0+0=0.45K=4,y0=0.5533CCI1=33=0.92,X=0,y2=013.6i3=-=1,y3=012y=0.55+0+0=0.55K=6.75,y=0.5012CCi1=1,y=0,y2=0112i3=-=1,y3=012y=0.50+0+0=0.50求各柱的杆端弯矩：第二层：M上=2.1/i11-0.45)3.3=3.78M上=3.5施M-0.45)3.3=5.64M下=2.1的0.43.3=3.78M下=3.550.453.3=5.64第一层：.553.6=24.0M上=7.08?(10.6)?3.69.0M上=10.4?(10.55?3.612.0M下=7.0的0.63.6=18.0绘制各横梁与