塔吊基础设计(四桩)

塔吊基础设计(四桩)计算书计算参数基本参数采用2台QTZ100塔式起重机，塔身尺寸1.80m，基坑底标高-11.90m；现场地面标高-9.80m，承台面标高-10.40m；采用钻(冲)孔桩基础，地下水位-0.50m。计算参数塔吊基础受力情况MMF=基础顶面所受垂直力kF=F=基础顶面所受垂直力kF=基础顶面所受水平力hM=基础顶面所受倾覆力矩M=基础所受扭矩zMz荷载工况基础荷载P(kN)M(kN・m)FkFhMMZ工作状态646.3022.701864.30413.60非工作状态537.4091.201829.400塔吊基础受力示意图比较塔吊的工作状态和非工作状态的受力情况，塔吊基础按工作状态计算如图F=646.30kN,F=22.70kNk hM=1864.30+22.70X1.40=1896.08kN・mFk，=646-30X1-35=872-51kN，Fh，=22-70X1-35=30-65kNM=(1864.30+22.70X1.40)X1.35=2559.71kN-mk2)桩顶以下岩土力学资料序号地层名称厚度L(m)极限侧阻力标准值qik(kPa)岩石饱和单轴抗压强度标准值fk(kPa)q'sik*i(kN/m)抗拔系数入1入q』isiki(kN/m)1中砂5.8053.00307.400.40122.962淤泥质土4.6020.0092.000.7064.403粉砂4.8022.00105.600.7073.924粗砂2.0086.00240.00172.000.5086.00桩长17.20EqL sik*__i 677.00E入qL i__sik*__i—347.28(3)基础设计主要参数基础桩采用4根©600钻(冲)孔灌注桩，桩顶标高-11.80m，桩端不设扩大头，桩端入粗砂2.00m；桩混凝土等级C30,f=14.30N/mm2,E=3.00X104N/mm2；f=1.43N/mm2，桩长17.20m；钢筋HRB400,f=360.00N/mm2,c c t yE=2.00X105N/mm2。s承台尺寸长(a)=6.00m,宽(b)=6.00m,高(h)=1.50m，桩中心与承台中心2.20m,承台面标高-10.40m；承台混凝土等级C35，f=1.57N/mm2,f=16.70N/mm2,Y=25kN/m3。t c 砼G=abhY=6.00X6.00X1.50X25=1350.00kNk 1砼

比1=Z270kN7二承台1B96.08kN-nn吕U(}] 44U06OGG6000塔吊基硼比1=Z270kN7二承台1B96.08kN-nn吕U(}] 44U06OGG6000塔吊基硼DO寸吕ing疋:塔吊基础尺寸示意图桩顶作用效应计算（1）竖向力1）轴心竖向力作用下N=(F+G)/n=(646.30+1350.00)/4=499.08kNKKK偏心竖向力作用下按照M作用在对角线进行计算，M=M=1896.08kN.m,y=2.2OX2o.5=3.11mx xk iN=(F+G)/n+My/Sy2=(646.30+1350.00)/4±(1896.08X3.11)/(2X3.112)=499.08±304.84k k k xi iN=803.92kN,N=194.24kN(基桩不承受竖向拉力)。kmax kmin(2)水平力H=F/n=22.70/4=5.68kNikh桩基竖向承载力验算单桩竖向极限承载力标准值计算d=0.60m=600mm,h=2.00m,h/d=2.00/0.60=3.33,查表得：Z=1.01A=nd2/4=3.14X0.602/4=0.28m2pQ=uEq』=ndYq』=3.14X0.60X677.00=1275.47kNsk siki siaiQ=ZfA=1.01X240.00X0.28=67.87kN,Q=Q+Q=1275.47+67.87=1343.34kNRkrRkp ukskRkR=1/KQ=1/2X1343.34=671.67kNa uk桩基竖向力作用下1） 轴心竖向力作用下N=499.08kNVR=671.67kN,竖向承载力满足要求。TOC\o"1-5"\h\zk a2） 偏心竖向力作用下N=803.92kNVR=1.2X671.67=806.00kN,竖向承载力满足要求。kmax a单桩水平承载力验算（1）单桩水平承载力特征值计算a=E/E=2.00X105/3.00X104=6.67,r=2,Z=0.50Esc m NP=0.2+(2000-600)/(2000-300)X(0.65-0.2)=0.57%gW=nd/32[d2+2(E/E-1)Pd2]o SC g0=(3.14X0.60/32)X[0.602+2X(6.67-1)X0.57%X(0.60-2X0.10)2]=0.02m3I=Wd/2=0.02X0.60/2=0.0060m4ooEI=0.85EI=0.85X3.00X107X0.0060=153000kN.m2Co查表得:m=6.00X103kN/m4,b=0.9(1.5d+0.5)=1.26m=1260mmoa=(mb/EI)o.2=(6.OOX1OOOX1.26/153OOO)o.2=O.55oCaL=0.55X17.20=9.46>4,按aL=4,查表得：u=0.768mN=(F+.2G)/n=(872.51+1.2X1350.00)/4=623.13kNkk kA=nd2/4[1+(E/E-1)P]=3.14X0.602/4X(1+(6.67-1)X0.57%)=0.29m2n sc gR=(0.75aYfW/u)(1.25+22p)(1+ZN/yfA)ha mt0m g Nkmtn=(0.75X0.55X2X1.43X1000X0.02/0.768)X(1.25+22X0.57%)X[l+0.50X623.13/(2X1.43X1000X0.29)]=58.13kN(2)桩基水平承载力计算H=5.68kNVR=58.13kN，水平承载力满足要求。ik ha抗拔桩基承载力验算抗拔极限承载力标准值计算T=l/nu工入qL=l/4X(2.20X2+0.60)X4X347.28=1736.40kNgk 1 isikiT=S入quL=347.28X3.14X0.60=654.28kNuk isikii抗拔承载力计算G=6.00X6.00X17.10X(18.80-10)/4=3565.08kNgpG=3.14X0.302X17.20X(25—10)=170.80kNpT/2+G=1736.40/2+3565.08=4433.28kNgk gpT/2+G=654.28/2+170.80=497.94kNuk p由于基桩不承受竖向拉力，故基桩呈整体性和非整体性破坏的抗拔承载力满足要求。抗倾覆验算円L44001 500(} qr倾覆点示意图b=6.00/2+2.20=5.20ma=6.00/2=3.00mTOC\o"1-5"\h\zi i倾覆力矩M=M+Fh=1864+22.70X(11.9010.40)=1898.05kN・m倾 h抗倾覆力矩M』(Fk+Gk)a+2(T/2+G)b抗 kk i uk pi=(646.30+1350.00)X3.00+2X(654.28/2+170.80)X5.20=11167.48kN.mM/M=11167.48/1898.05=5.88抗倾抗倾覆验算5.88>1.6,满足要求。(1)桩身承载力验算正截面受压承载力计算按照M作用在对角线进行计算，M=M=2559.71kN-m,y=2.2OX2o.5=3,11mx xk iN=(F‘+1.2G)/n土My/Sy2=(872.51+1.2X1350.00)/4+(2559.71X3.11)/(2X3.112)k k k xi i=623.13+411.53N=1034.66kN,N=211.60kNkmax kmin甲=0.70,甲fA=0.70X14.30X1000X0.28=2802.80kNc ccp正截面受压承载力=2802.80kN>N=1034.66kN,满足要求。kmax配筋计算配筋率P=P=0.57%gA=pA=0.57%X0.28X106=1596mm2,采用HRB400,f=360.00N/mm2取620s P yA=6X314=1884mm2〉A=1596mm2(满足要求)si s正截面受拉承载力计算fA=360X1884=678240N=678.24kNysfA=678.24kN>N=211.60kN,正截面受拉承载力满足要求。ys kminM/(4A)=1898.05X1000/(4X2.20X1884)=114.48N/mm2倾xlsM/(4xA)=114.48N/mm2<360.00N/mm2,满足要求。TOC\o"1-5"\h\z倾 1s(2)承台受冲切承载力验算塔身边冲切承载力计算F=F—1.2SQ=F，=872.51kN,h=1.50-0.10=1.40m=1400mmi ikk oB=1.0+[(2000—1500)/(2000—800)]X(0.9—1.0)=0.96hpa=2.20-0.60/2-1.80/2=1.00m,入=a/h=1.00/1.40=0.710 0oB=0.84/(0.71+0.2)=0.92,u=4X(1.80+1.40)=12.80m0 mBBufh=0.96X0.92X12.80X1.57X1000X1.40=24848.30kNhp0mTo承台受冲切承载力=24848.30kN>F=872.51kN,满足要求。l角桩向上冲切力承载力计算N=N,=F,/n+My/Sy2=872.51/4+2559.71X3.11/(2X3.112)=629.66kNTOC\o"1-5"\h\zlk k xi iV=2N,=2X629.66=1259.31kNk入=入=a/h=1.00/1.40=0.71,c=c=0.80+0.30=1.10m1x 1y 0o 1 2B=B=0.56/(入+0.2)=0.56/(0.71+0.2)=0.621x 1y 1x[B(c+a/2)+B(c+a/2)]Bfh1x2 1y 1y1 1x hpTo=0.62X(1.10+1.00/2)X2X0.96X1.57X1000X1.40=4186.4CkN角桩向上冲切承载力=4186.4kN>V=1259.31kN,满足要求。承台受剪切承载力验算N,=F,/n+My/Sy2=872.51/4+2559.71X3.11/(2X3.112)=629.66kNTOC\o"1-5"\h\zk k xi iV=2N,=2X629.66=1259.32kNkB=(8OO/h)1/4=(8OO/14OO)o.25=O.87,入=&/h=1.00/1.40=0.71hs o 0oa=1.75/(入+1)=1.75/(0.71+1)=1.02，B=6.00m=6000mmBafBh=0.87X1.02X1.57X1000X6.00X1.40=11703.03kNhs T0o承台受剪切承载力=11703.03kN>V=1259.32kN,满足要求。(4)承台抗弯验算1)承台弯矩计算N=F/n+My/Sy2=872.51/4+2559.71X3.11/(2X3.112)=629.66kN,x=2.20mik xi i iM=SNx=2X629.66X2.20=2770.50kN.mii

2）承台配筋计算承台采用HRB400,f=360.00N/mm2yA=M/0.9fh=2770.50X106/（0.9X360X1400）=6108mm2s yo取30 25@198mm（钢筋间距满足要求），A=30X491=14730mm2s承台配筋面积14730mm2>8400mm2,满足要求。O0\O0\OgS■lO8800Ki：2200|Ki=22aO3006000计算结果基础桩钻(冲)孔4根©600灌注桩，桩顶标高-11.80m，桩长17.20m，桩端入粗砂2.00m；桩混凝土C30,，桩身钢筋采用6