塔吊基础设计(单桩)计算书.doc

塔吊基础设计(单桩)计算书工程名称：址山碧桂园3、4号楼二层悬挑编制单位：1.计算参数（1）基本参数采用1台QZT80(5214)塔式起重机，塔身尺寸1.70m,基坑开挖深度-4.80m；现场地面标高0.00m,承台面标高-4.80m；采用钻（冲）孔基础，地下水位-3.00m。（2）计算参数1）塔机基础受力情况荷载工况基础荷载P(kN)M(kN.m)FkFhMMZ工作状态532.0074.001665.00420.00非工作状态619.0031.001866.000比较桩基础塔机的工作状态和非工作状态的受力情况，塔机基础按非工作状态计算如图Fk=619.00kN，Fh=31.00kN，M=1866.00+31.01.30=1906.30kN.mFk=619.001.35=835.65kN，Fh，=31.001.35=41.85kNMk=(1866.00+31.01.30)1.35=2573.51kN.m2）桩顶以下岩土力学资料序号地层名称厚度极限侧阻力岩石饱和单轴抗压强度qsik*i抗拔系数iqsik*iL(m)标准值qsik(kPa)标准值frk(kPa)(kN/m)i(kN/m)1填土0.2040.008.000.403.202填土1.4020.0028.000.5014.003粘性土3.2053.00169.600.5084.804中砂1.9053.00100.700.5050.355卵石1.80140.00252.000.50126.006粉质粘土2.2084.00184.800.5092.407中风化砾岩0.80140.009.00112.000.5056.00桩长11.50qsik*i855.10iqsik*i426.753）基础设计主要参数基础桩采用1根1200钻（冲）孔灌注桩，桩顶标高-6.10m，桩端不设扩大头，桩端入中风化砾岩 0.80m；桩混凝土等级C25，fC=11.90N/mm2 ,EC=2.80104N/mm2；ft=1.27N/mm2，桩长11.50m；钢筋HRB335,fy=300.00N/mm2 ,Es=2.00105N/mm2承台尺寸长(a)=5.00m、宽(b)=5.00m、高(h)=1.40m；桩中心与承台中心重合,承台面标高-4.80m；承台混凝土等级C25,ft=1.27N/mm2,fC=11.90N/mm2,砼=25kN/m3。Gk=abh砼=5.005.001.4025=875.00kN2.桩顶作用效应计算（1）轴心竖向力作用下：Nk=(FkGk)/n=(619.00+875.00)/1=1494.00kN （2）水平力作用下：Hik=Fh /n=31.00/1=31.00kN3.桩基竖向承载力验算（1）单桩竖向极限承载力标准值计算hr=0.80m,d=1.20m=1200mm,hr/d=0.80/1.20=0.67,查表得，r=0.70Ap=d2/4=3.141.44/4=1.13m2 Qsk=uqsiki =dqsiai=3.141.20855.10=3222.02kNQrk=rfrkAp=0.7091.13=7.12kN，Quk=Qsk+Qsk=3222.02+7.12=3229.14kNRa=1/KQuk=1/23229.14=1614.57kN4.桩基竖向承载力计算轴心竖向力作用下 Nk=1494.00kNRa=1614.57kN,竖向承载力满足要求。5.桩基水平承载力验算（1）单桩水平承载力特征值计算E=Es/Ec=2.00105/2.80104=7.14,m=2,N=0.50g=0.2+(2000-1200)/(2000-300)(0.65-0.2)=0.41%Wo=d/32d22(ES/EC1)gd02=3.141.20/32(1.202+2(7.14-1)0.41%(1.20-20.10)2)=0.18m3Io=Wod/2=0.181.20/2=0.11m4EI=0.85ECIo=0.852.801070.11=2618000kN.m2查表得:m=35.00103kN/m4 ， bo =0.9(d+1)=1.98m=(mbo/ECI)0.2=(35.0010001.98/2618000)0.2=0.48L=0.4811.50=5.564，按L=4 查表得: Vm=0.768Nk=(Fk1.2Gk)/n=(835.65+1.2875.00)/1=1885.65kN An=d2/41(Es/Ec-1)Pg=1.13(1+6.140.41%)=1.16m2RHa=(0.75mftW0/Vm)(1.25+22g)(1+NN1k/mftAn)=(0.750.4821.2710000.180.7680)(1.25 + 220.41/100)1 + 0.501885.65/(21.2710001.16)=379.13kN(2)桩基水平承载力Hik=31.00kNRha=379.13kN,水平承载力满足要求。6.抗拔桩基承载力验算（1）抗拔极限承载力标准值计算Tgk=1/nu1iqsikLi=1.204426.75=2048.40kNTuk=iqsikuiLi=426.753.141.20=1607.99kN(2)抗拔承载力计算Ggp=5.005.0011.40(18.80-10)/1=4716.00kNGp=3.140.60.611.50(25-10)=335.16kNTgk/2+Ggp=2048.40/2+4716.00=5740.20kN，Tuk/2+Gp=1607.99/2+335.16=1139.16kN7.抗倾覆验算bi=5.00/2=2.50m倾覆力矩M倾=MFhh=1866.00+31.00(7.80-4.80)=1959.00kN.m抗倾覆力矩M抗=（FkGk）bi(Tuk/2+Gp)bi=(619.00+875.00)2.50+(1607.99/2+335.16)2.50=6582.89kN.mM抗/M倾=6582.89/1959.00=3.36抗倾覆验算3.361.6,满足要求。8.桩身承载力验算(1)正截面受压承载力计算Nk =(Fk1.2Gk)/n=(835.65+1.2875.00)/1=1885.65kNc=0.70,cfcAp=0.7011.9010001.13=9412.90kN正截面受压承载力=9412.90kNNK=1885.65kN,满足要求。（2）配筋计算采用HRB335钢筋,fy=300.00N/mm2,按照配筋率=g=0.41%计算：As1=AP=0.41%1.13106=4633mm2 桩身钢筋抗拔计算As2=2M倾/dfy=21959.00106/(1200300)=10883mm2比较As1和As2,按As2配筋，取3620，As=36314=11304mm2AS2=10883mm2 (满足要求)9.承台受冲切承载力验算只考虑塔身边冲切承载力计算F=F1.2Qik=Fk=835.65kN，ho=1.40-0.10=1.30m=1300mmhp=1.0+(2000-1400/(2000-800)(0.9-1.0)=0.950=(5.00-1.70)/2=1.65m,=0/ho=1.65/1.30=1.270=0.84/(1.27+0.2)=0.57um=4(1.70+1.65)=13.40mhp0umftho=0.950.5713.401.2710001.30=11979.82kN 承台受冲切承载力=11979.82kNFk=835.65kN,满足要求。10. 承台受剪切承载力计算V=Nk=Fk/n=835.65/1=835.65kNhs=(800/ho)1/4=(800/1300)0.25=0.89,=0/ho=1.65/1.30=1.27=1.75/(+1)=1.75/(1.27+1)=0.77,b0=5.00m=5000mmhsftb0ho=0.890.771.2710005.001.30=5657.15kN 承台受剪切承载力=5657.15kNV=835.65kN,满足要求。11.承台配筋计算（1）承台弯矩计算Ni=Fk=835.65kN，xi =0.60mM=Nixi=835.650.60=501.39kN.m（2）承台配筋计算基础采用HRB335钢筋，fy=300N/mm2,最小配筋率=0.15%计算配筋As1=M/0.9fyho=501.39106/(0.93001300)=1428mm2As2=bho=0.001550001300=9750mm2比较As1和As2，按As2配筋,取3220159mm (钢筋间距满足要求) As=32314=10048 mm2承台配筋面积=10048mm29750mm2,满足要求。12.计算结果（1）基础