超高层塔吊基础设计与施工方案(通过专家论证)

华润中心C2区塔吊基础设计及施工方案#(图4)基础布置图承台及其上土的自重荷载标准值：Gk=bl(hYc+h'Y')=5.755X5X(1.3X25+0X19)=935.188kN承台及其上土的自重荷载设计值：G=1.35Gk=1.35X935.188=1262.503kN桩对角线距离：L=(ab2+al2)o.5=(3.22+3.22)o.5=4.525m7.3.1荷载效应标准组合轴心竖向力作用下：Qk=(Gk1+Gk)/n=(464.1+935.188)/4=349.822kN荷载效应标准组合偏心竖向力作用下：Q=(Gk1+G)/n+(M+Fh)/L=(464.1+935.188)/4+(1335+14.1kmaxkkVk/4.525=648.868KNQ=(Gk1+G)/n-(M+Fh)/L=(464.1+935.188)/4-(1335+14.1kminkkVk/4.525=50.775KN7.3.2荷载效应基本组合荷载效应基本组合偏心竖向力作用下：Q=(F+G)/n+(M+Fh)/L=(511.2+1262.503)/4+(1.35X1335+14.1X1.35Xmaxv/4.525=847.139kNQ=(F+G)/n-(M+Fh)/L=(511.2+1262.503)/4-(1.35X1335+14.1X1.35Xminv/4.525=39.713kN7.4桩承载力验算7.4.1桩基竖向抗压承载力计算桩身周长：u=nd=3.14159X0.9=2.827m桩端面积：A=nd2/4=3.14159X0.9X0.9/4=0.636m2p承载力计算深度：min(b/2,5)=2.5m承台底净面积：A=(bl-nA)/n=(5X5.755-4X0.636)/4=6.558m2cp复合桩基竖向承载力特征值：R=^uSq・l+q・A+nfA=1X2.827X534.78+1651.568X0.636+0.1asiaipapcakcX6.558X120.092=2641.487kNQ=349.822kNWR=2641.487kNkaQ=648.868kNW1.2R=1.2X2641.487=3169.784kNkmaxa满足要求7.4.2桩基竖向抗拔承载力计算Q=50.775KN20kNkmin满足要求不需要进行桩基竖向抗拔承载力计算！7.4.3桩身承载力计算纵向普通钢筋截面面积：A=nnd2/4=22X3.14159X16/1000X16/1000/4=0.004m2s、轴心受压桩桩身承载力荷载效应基本组合下的桩顶轴向压力设计值：Q=Q=847.139kNmax桩身结构竖向承载力设计值：R=4300kNQ=847.139kN<=R=4300kN满足要求、轴心受拔桩桩身承载力Q=50.775kN±0kNkmin满足要求不需要进行轴心受拔桩桩身承载力计算！7.4.4桩身构造配筋计算《塔式起重机混凝土基础工程技术规程》JGJ/T187-2009,第6.2.2条：纵向钢筋的最小配筋率，对于灌注桩不宜小于0.2%~0.65%(小直径桩取最高值)；对于预制桩不宜小于0.8%；对于预应力管桩不宜小于0.45%。As/Ap=0.004/0.636X100=0.695%±0.65%满足要求7.5承台计算7.5.1荷载计算塔身截面对角线上的荷载设计值：F二F/4+M/(2o.5B)=(464.1+47.1)/4+1.35X1335/(2o.5X1.6)=924.289kNmaxF二F/4-M/(2o.5B)=(464.1+47.1)/4-1.35X1335/(2o.5X1.6)=-668.689kNmin

r（图5）简图（图（图5）简图（图6）弯矩图(图7)剪力图V=853.488kNmaxM=1800.74kN・mmaxM=0kN•mmin7.5.2受剪切计算截面有效高度：h=h-6-D/2=1.3-50/1000-25/1000/2=1.238m0c受剪切承载力截面高度影响系数：B=(d/h0)1/4=(1.5/1.238)0.25=1.049hs塔吊边至桩边的水平距离：a=(a-B-d)/2=(3.2-1.6-0.9)/2=0.35m1bba=(a-B-d)/2=(3.2-1.6-0.9)/2=0.35m1ll计算截面剪跨比：入'二a/h=0.35/1.238=0.283,b1b0取入=0.283；b入'二a/h=0.35/1.238=0.283,l1l0取入=0.283；l承台剪切系数：a=1.75/(入+1)=1.75/(0.283+1)=1.364bba=1.75/(入+1)=1.75/(0.283+1)=1.364llBaflh=1.049X1.364X1.57X1000X5.755X1.238=16004.652KNhsbt0V=F/n+M/L=(464.1+47.1)/4+1.35X1335/4.525=526.045kNV=526.045kNWmin(Bafbh,Baflh)=13904.997kNhsbt0hslt0满足要求7.5.3受冲切计算塔吊对承台底的冲切范围：B+2h=1.6+2X1.238=4.075m0a=3.2mWB+2h=5+2X1.238=7.475m,a=3.2mWB+2h1.6+2X1.238=4.075mb0l0=角桩位于冲切椎体以内,可不进行角桩冲切的承载力验算！7.5.4承台配筋计算(1)、承台梁底部配筋a=M/(afl'h2)=0/(1X16.7X1X1000X(1.238X1000)2)=0S1min1c0Z=1-(1-2a)0.5=1—(1—2X0)0.5=01S1Y=1—Z/2=1—0/2=1S11A=M/(Yhf)=0/(1X1.238X1000X300)=0mm2S1minS10y1最小配筋率：P=max(0.2,45f/f)=max(0.2,45X1.57/300)=0.236%ty1梁底需要配筋：A=max(A,Plh)=max(0,0.236/100X1X1000X1.238X1S101000)=2914.313mm2a为钢筋间距A'=(nd2/4)nl=3.1415X222/4X8=3040.972s1梁底部实际配筋：A'=3040.972mm2±A=2914.313mm2s11满足要求、承台梁上部配筋a=M/(afl'h2)=1800.74/(1X16.7X1X1000X(1.238XS2max2c01000)2)=1e-07Z=1-(1-2a)0.5=1—(1—2X1e—07)0.5=1e—072S2=1—Z/2=1—1e—07/2=1S22A=M/(Yhf)=1800.74/(1X1.238X1000X300)=0.005mm2S2maxS20y2最小配筋率：P二max(0.2,45f/f)=max(0.2,45X1.57/300)=0.236%ty2梁上部需要配筋：A=max(A,Pl'h)=max(0.005,0.236/100X1X1000X2S201.238X1000)=2914.313mm2a为钢筋间距A'=(nd2/4)n2=3.1415X222/4X8=3040.972s2梁上部实际配筋：A'=3040.972mm2±A=2914.313mm2S2S2满足要求、梁腰筋配筋梁腰筋按照构造配筋4①14、承台梁箍筋计算箍筋抗剪计算截面剪跨比：入'=(L—20.5B)/(2h)=(5.755—20.5X1.6)/(2X01.238)=1.411取入二1.5混凝土受剪承载力：1.75fl'h/(入+1)=1.75X1.57X1Xt01.238/(1.5+1)=1.36kNA=3.142Xd2/4=3.142X12X12/4=113.112sv1nA/s=4X113.112/200=2.262sv1=V=1.36kNW0.7fl'h+1.25fh(nA/s)=0.7X1.57X1X1.238+1.25Xmaxt0yv0sv1300X1.238X(4X113.112/200)=1051.181kN满足要求配箍率验算P=nA/(l's)=4X113.112/(1X1000X200)Xsvsv1100=0.226%>=0.24f/f=0.24X1.57/300X100=0.126%tyv满足要求、板底面长向配筋面积板底需要配筋：A=Pbh=max(0.2,45X1.57/300)/100X5X1000X1.238XS101000=14571.563mm2承台底长向实际配筋：A'=3.1415X252/4X(5X1000/170+1)=14927.9mm2±A=1457