塔吊基础设计(四桩).doc

塔吊基础设计(四桩)计算书工程名称：海南工商职业学院22#教工住宅楼编制单位：江苏苏兴建筑工程有限公司1.计算参数 （1）基本参数采用1台QZT80A(5613)塔式起重机，塔身尺寸1.80m,塔吊基础处开挖深度为-5.80m；现场地面标高-0.20m，承台面标高-4.60m。1）塔吊基础受力情况荷载工况基础荷载P(kN)M(kN.m)FkFhMMZ工作状态950.0030.001600.00340.00非工作状态850.0070.001800.000比较桩基础塔吊的工作状态和非工作状态的受力情况，塔吊基础按非工作状态计算如图；Fk=850.00kN，Fh=70.00kN，M=1800.00+70.001.22=1885.40kN.mFk，=850.001.35=1147.50kN，Fh，=70.001.35=94.50kN，Mk=(1800.00+70.001.22)1.35=2545.29kN.m2）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qsik(kPa)极限端阻力标准值qpk(kPa)qsiki(kN/m)抗拔系数iiqsik*i(kN/m)1中砂6.0050.00300.000.50150.002粉砂8.5035.00297.500.70208.253粉质粘土8.5070.001000.00595.000.70416.50桩长23.00qsik*Li1192.50iqsik*Li774.753）基础设计主要参数基础桩采用4根400预应力管桩,桩顶标高-5.82m；桩混凝土等级C80,fC=35.90N/mm2 ,EC=3.80104 N/mm2；ft=2.22N/mm2,桩长23.00m,管道壁厚95mm；钢筋HRB335，fy=300.00N/mm2,Es=2.00105N/mm2；承台尺寸长(a)=5.80m,宽(b)=5.80m,高(h)=1.32m；桩中心与承台中心2.20m,承台面标高-4.60m；承台混凝土等级C35，ft=1.57N/mm2,fC=16.70N/mm2,砼=25kN/m3。Gk=abh砼=5.805.801.3225=1110.12kN塔吊基础尺寸示意图2.桩顶作用效应计算（1）竖向力1）轴心竖向力作用下Nk=(FkGk)/n=(850.00+1110.12)/4=490.03kN2）偏心竖向力作用下按照Mx作用在对角线进行计算，Mx=Mk=1885.40kN.m yi=2.2020.5=3.11mNk =(FkGk)/nMxyi/yi2=(850.00+1110.12)/4(1885.403.11)/(23.112)=490.03303.12Nkmax=793.15kN, Nkmax=186.91kN (基桩不承受竖向拉力)。(2)水平力Hik=Fh/n=70.00/4=17.50kN3.单桩允许承载力特征值计算 管桩外径d=400mm=0.40m，内径d1=400-295=210mm=0.21m，hb=8.50hb/d=8.50/0.40=21.25,p =0.80（1）单桩竖向极限承载力标准值计算Aj=(d2-d12)/4=3.14(0.402-0.212)/4=0.09m2,Apl=d12/4=3.140.212/4=0.03m2Qsk=uqsiki=dqsiki=3.140.401192.50=1497.78kNQpk=qpk(Aj+pApl)=1000.00(0.09+0.800.03)=114.00kNQuk= QskQpk=1497.78+114.00=1611.78kNRa=1/KQuk=1/21611.78=805.89kN(2)桩基竖向承载力计算1）轴心竖向力作用下 Nk=490.03kNRa=805.89kN,竖向承载力满足要求。2）偏心竖向力作用下 Nkmax=793.15kNRa=1.2805.89=967.07kN,竖向承载力满足要求。4.桩基水平承载力验算(1)单桩水平承载力特征值计算I=(d4-d14)/64=3.14/64(0.404-0.214)=0.0012m4EI=EcI=3.801070.0012=45600kN.m2查表得:m=2.00103kN/m4, Xoa=0.010mbo=0.9(1.5d+0.5)=0.99m=990mm=(mbo/ ECI)0.2=(2.0010000.99/45600)0.2=0.53L=0.5323.00=12.194,按 L=4,查表得: x=2.441RHa=0.75(3EI/x)oa=0.75(0.53345600/2.441)0.01=20.86kN（2）桩基水平承载力计算Hik=17.50kNRha=20.86kN,水平承载力满足要求。5.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=1/4(2.202+0.40)4774.75=3718.80kNTuk=iqsikuiLi=774.753.140.40=973.09kN(2)抗拔承载力计算Ggp=5.805.8022.90(18.80 - 10)/4=1694.78kNGp=0.0923.00(25 - 10)=31.05kNTgk/2+Ggp=3718.80/2+1694.78=3554.18kNTuk/2+Gp=973.09/2+31.05=517.60kN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。6.抗倾覆验算a1=5.80/2=2.90m,bi=5.80/2+2.20=5.10m，倾覆力矩M倾=MFhh=1800+70.001.22=1885.40kN.m抗倾覆力矩M抗=（FkGk）ai2(Tuk/2+Gp)bi=(850.00+1110.12)2.90+2(973.09/2+31.05)5.10=10963.82kN.mM抗/M倾=10963.82/1885.40=5.82抗倾覆验算5.821.6,满足要求。7.桩身承载力验算(1)正截面受压承载力计算 按照Mx作用在对角线进行计算，Mx=Mk=2545.29kN.m，yi=2.2020.5=3.11mNk=(Fk1.2Gk)/nMxyi/yi2=(1147.50+1.21110.12)/4(2545.293.11)/(23.112)=619.91409.21Nkmax=1029.12kN，Nkmax=210.70kNc=0.85cfcAj=0.8535.9010000.09=2746.35kN正截面受压承载力=2746.35kNNkmax=1029.12kN,满足要求。(2)预制桩插筋受拉承载力验算插筋采用HRB335，fy=300.00N/mm2，取622，As=6380=2280mm2 fyAs=3002280=684000N=684.00kN fyAs=684.00kNNkmin=210.70kN,正截面受拉承载力满足要求。 M倾/(4x1As)=1885.401000/(42.202280)=93.97N/mm2 M倾/(4x1As)=93.97N/mm2300.00N/mm2,满足要求。 (3)承台受冲切承载力验算1）塔身边冲切承载力计算F=F1.2Qik=Fk，=1147.50kN，ho=1.32-0.10=1.22m=1220mmhp=1.0+(2000-1320)/(2000-800)(0.9-1.0)=0.940=2.20-0.40/2-1.80/2=1.10m,=0/ho=1.10/1.22=0.900=0.84/(+0.2)=0.84/(0.90+0.2)=0.76um=4(1.80+1.22)=12.08mhp0umftho=0.940.7612.081.5710001.22=16529.81kN承台受冲切承载力=16529.81kNFt=1147.50kN,满足要求。2)角桩向上冲切力承载力计算N1=Nk，=Fk，/n+ Mxyi/yi2=1147.50/4+2545.293.11/(23.112)=696.09kN1x=1y=0/ho=1.10/1.22=0.90,c1=c2=0.70+0.20=0.90m1x=1y=0.56/(1x+0.2)=0.56/(0.90+0.2)=0.511x(c2+1y/2)+1y(c1+1x/2)hpftho=0.51(0.90+1.10/2)20.941.5710001.22=2662.90kN角桩向上冲切承载力=2662.90kN2Nl=1392.17kN,满足要求。3)承台受剪切承载力验算Nk，=Fk，/n+ Mxyi/yi2=1147.50/4+2545.293.11/(23.112)=696.09kNV=2Nk，=2696.09=1392.18kNhs=(800/ho)1/4=(800/1220)0.25=0.90,=0/ho=1.10/1.22=0.90=1.75/(+1)=1.75/(0.90+1)=0.92,b0=5.80m=5800mmhsftb0ho=0.900.921.5710005.801.22=9198.52kN承台受剪切承载力=9198.52kN2Nl=1392kN,满足要求。(4)承台抗弯验算1)承台弯矩计算Ni=Fk，/n+ Mxyi/yi2=1147.50/4+2545.293.11/(23.112)=696.09kN,Xi=1.30mM=NiXi=2696.091.30=1809.82kN.m2)承台配筋计算承台采用HRB335，fy=300.00N/mm2As=M/0.9fyho=1809.82106/(0.93001220)=5494mm2取2922 198mm (钢筋间距满足要求),As=29380=11020mm2承台配筋面