三桩桩基承台计算项目名称 ______________ 日 期 __________________设 计 者 _______________ 校 对 者 ________________一、设计依据《建筑地基基础设计规范》 (GB50007-2011) ① 《混凝土结构设计规范》(GB50010- 2010) ② 《建筑桩基技术规范》 (JGJ 94 －2008) ③二、示意图三、计算信息构件编号 : CT21. 几何参数矩形柱宽 bc=500mm 圆桩直径 d=600mm承台根部高度 H=1250mm x 方向桩中心距 A=1800mm y 方向桩中心距B=1800mm 承台边缘至边桩中心距C=600mm2. 材料信息柱混凝土强度等级 : 承台混凝土强度等级 桩混凝土强度等级 : 承台钢筋级别 : 3. 计算信息 结构重要性系数 : ft_c=1.57N/mm ft_b=1.43N/mm ft_p=1.43N/mm HRB400 fy=360N/mm 2 丫 o=1.04. 作用在承台顶部荷载标准值Fgk=4418.000kN Fqk=0.000kNMgxk=81.000kN*m Mqxk=0.000kN*mFk=Fgk+Fqk=4418.000+(0.000)=4418.000kNMxk=Mgxk+Fgk*(B2-B1)/2+Mqxk+Fqk*(B2-B1)/2=81.000+4418.000*(0.000-0.000)/2+(0.000)+0.000*(0.000-0.000)/2=81.000kN*mMyk=Mgyk+Fgk*(A2-A1)/2+Mqyk+Fqk*(A2-A1)/2=6.000+4418.000*(0.000-0.000)/2+(0.000)+0.000*(0.000-0.000)/2=6.000kN*mVxk=Vgxk+Vqxk=5.000+(0.000)=5.000kNVyk=Vgyk+Vqyk=57.000+(0.000)=57.000kNF1=rg*Fgk+rq*Fqk=1.20*(4418.000)+1.40*(0.000)=5301.600kN承台类型 : 三桩承台 计算类型 : 验算截面尺寸纵筋合力点至近边距离 as=155mm矩形柱高hc=550mm C35 C30 C30 2 fc_c=16.7N/mm fc_b=14.3N/mm 2 2fc_p=14.3N/mm 2 Mgyk=6.000kN*mVgxk=5.000kNVgyk=57.000kN 永久荷载分项系数 可变荷载分项系数 Mqyk=0.000kN*m Vqxk=0.000kN Vqyk=0.000kN rg=1.20 rq=1.40Mx1=rg*(Mgxk+Fgk*(B2-B1)/2)+rq*(Mqxk+Fqk*(B2-B1)/2)=1.20*(81.000+4418.000*(0.000-0.000)/2)+1.40*(0.000+0.000*(0.000-0.000)/2) =97.200kN*mMy1=rg*(Mgyk+Fgk*(A2-A1)/2)+rq*(Mqyk+Fqk*(A2-A1)/2)=1.20*(6.000+4418.000*(0.000-0.000)/2)+1.40*(0.000+0.000*(0.000-0.000)/2) =7.200kN*m Vx1=rg*Vgxk+rq*Vqxk=1.20*(5.000)+1.40*(0.000)=6.000kNVy1=rg*Vgyk+rq*Vqyk=1.20*(57.000)+1.40*(0.000)=68.400kNF2=1.35*Fk=1.35*4418.000=5964.300kN Mx2=1.35*Mxk=1.35*81.000=109.350kN*mMy2=1.35*Myk=1.35*6.000=8.100kN*m Vx2=1.35*Vxk=1.35*5.000=6.750kNVy2=1.35*Vyk=1.35*57.000=76.950kNF=max(|F1|,|F2|)=max(|5301.600|,|5964.300|)=5964.300kNMx=max(|Mx1|,|Mx2|)=max(|97.200|,|109.350|)=109.350kN*mMy=max(|My1|,|My2|)=max(|7.200|,|8.100|)=8.100kN*mVx=max(|Vx1|,|Vx2|)=max(|6.000|,|6.750|)=6.750kNVy=max(|Vy1|,|Vy2|)=max(|68.400|,|76.950|)=76.950kN四、计算参数1.承台总长 Bx=C+A+C=0.600+1.800+0.600=3.000m2.承台总宽 By=C+B+C=0.600+1.800+0.600=3.000m3.承台根部截面有效高度 ho=H-as=1.250-0.155=1.095m4.圆桩换算截面宽度 bp=0.8*d=0.8*0.600=0.480m五、内力计算1.各桩编号及定位座标如上图所示 :0 仁arccos(0.5*A/B)=1.0470 2=2*arcsin(0.5*A/B)=1.0471号桩 (x1=-A/2=-0.900m, y1=-B*cos(0.5* 0 2)/3=-0.520m)2号桩 (x2=A/2=0.900m, y2=-B*cos(0.5* 0 2)/3=-0.520m)3号桩 (x3=0, y3=B*cos(0.5* 0 2)*2/3=1.039m)”x i=xj*2=1.620mXy i =yj*2+y 32=1.620m2 2 2 2N i=F/n-Mx*y i/Xy i2+My*x i/Xx i2+Vx*H*x i/Xx i2-Vy*H*y1/Xy i2N1=5964.300/3-109.350*(-0.520)/1.620+8.100*(-0.900)/1.620 +6.750*1.250*(-0.900)/1.620-76.950*1.250*(-0.520)/1.620 =1983.134kNN2=5964.300/3-109.350*(-0.520)/1.620+8.100*0.900/1.620+6.750*1.250*0.900/1.620-76.950*1.250*(-0.520)/1.620 =2001.509kNN3=5964.300/3-109.350*1.039/1.620+8.100*0.000/1.620 +6.750*1.250*0.000/1.620-76.950*1.250*1.039/1.620 =1979.656kN六、柱对承台的冲切验算1.XNi=0=0.000kNho1=h-as=1.250-0.155=1.095m2.a ox=A/2-bc/2-bp/2=1.800/2-1/2*0.500-1/2*0.480=0.410ma oy12=y2-hc/2-bp/2=0.520-0.550/2-0.480/2=0.005ma oy3=y3-hc/2-bp/2=1.039-0.550/2-0.480/2=0.524m3.入 ox= a ox/ho1=0.410/1.095=0.374入 oy12=a oy12/ho仁0.219/1.095=0.200入 oy3= a oy3/ho1=0.524/1.095=0.4794. B ox=0.84/(入 ox+0.2)=0.84/(0.374+0.2)=1.462B oy12=0.84/(入 oy12+0.2)=0.84/(0.200+0.2)=2.100B oy3=0.84/(入 oy3+0.2)=0.84/(0.479+0.2)=1.2386.计算冲切临界截面周长AD=0.5*A+C/ta n(0.5* 9 1)=0.5*1.800+0.600/ta n(0.5*1.047))=1.939mCD=AD*ta n( 9 1)=1.939*ta n(1.047)=3.359mAE=C/tan(0.5* 9 1)=0.600/tan(0.5*1.047)=1.039m6.1计算 Umx1Umx1=bc+a ox=0.500+0.410=0.910m6.2计算 Umx2Umx2=2*AD*(CD-C-|y1|-|y3|+0.5*bp)/CD =2*1.939*(3.359-0.600-|-0.520|-|1.039|+0.5*0.480)/3.359 =1.663m因 Umx2>Umx取 Umx2=Umx1=0.910mUmy=hc+a oy12+a oy3=0.550+0.219+0.524=1.293m因 Umy>(C*tan( 9 1)/tan(0.5* 9 1))-C-0.5*bpUmy=(C*tan(9 1)/tan(0.5* 9 1))-C-0.5*bp=(0.600*tan(1.047)/tan(0.5*1.047))-0.600-0.5*0.480 =0.960m7.计算冲切抗力因 H=1.250m 所以 B hp=0.963丫 o*Fl= 丫 o*(F-刀 Ni)=1.0*(5964.300 -0.000)=5964.30kN[ B ox*2*Umy+B oy12*Umx1+B oy3*Umx2]*B hp*ft_b*ho=[1.462*2*0.960+2.100*0.910+1.238*0.910]*0.963*1.43*1.095*1000=8808.946kN> 丫 o*Fl柱对承台的冲切满足规范要求七、角桩对承台的冲切验算1.Nl=max(N1,N2)=2001.509kNho1=h-as=1.250-0.155=1.095m2.a11=(A-bc-bp)/2=(1.800-0.500-0.480)/2=0.410ma12=(y3-(hc ＋d)*0.5)*cos(0.5* 9 2)=(1.039-(0.550-0.480)*0.5)*cos(0.5*1.047)=0.454m入 1仁 a11/ho=0.410/1.095=0.374B 1仁0.56/(入 11+0.2)=0.56/(0.374+0.2))=0.975C1=(C/tan(0.5* 9 1))+0.5*bp=(C/tan(0.5*1.047))+0.5*0.480=1.279m入 12=a12/ho=0.454/1.095=0.415B 12=0.56/(入 12+0.2)=0.56/(0.415+0.2))=0.911C2=(CD-C-|y1|-y3+0.5d)*cos(0.5* 9 2)=(3.359-0.600-|-0.520|-1.039+0.5*1.047)*cos(0.5*0.480)=1.247m3.因 h=1.250m 所以 B hp=0.963丫 o*NI=1.0*2001.509=2001.509kNB 11*(2*C1+a11)*(tan(0.5* 9 1))* B hp*ft_b*ho=0.975*(2*1279.230+410.000)*(tan(0.5*1.047))*0.963*1.43*1095.000 =2518.101kN> 丫o*Nl=2001.509kN底部角桩对承台的冲切满足规范要求丫 o*N3=1.0*1979.656=1979.656kNB 12*(2*C2+a12)*(tan(0.5* 9 2))* B hp*ft_b*ho=0.911*(2*1247.077+453.997)*(tan(0.5*1.047))*0.963*1.43*1095.000*1000=2337.378kN> 丫 o*N3=1979.656kN顶部角桩对承台的冲切满足规范要求八、承台斜截面受剪验算1.计算承台计算截面处的计算宽度2.计算剪切系数因 0.800ho=1.095m<2.000m, B hs=(0.800/1.095) 1/4=0.925 ay=|y3|-0.5*hc-0.5*bp=|1.039|-0.5*0.550-0.5*0.480=0.524 入 y=ay/ho=0.524/1.095=0.479B y=1.75/(入 y+1.0)=1.75/(0.479+1.0)=1.18322bxo=A*(2/3+hc/2/sqrt(B 2-(A/2) 2))+2*C=1.800*(2/3+0.550/2/sqrt(1.800 2-(1.800/2) 2))+2*0.600=2.718m丫 o*Vy=1.0*3984.644=3984.644kNB hs*B y*ft_b*bxo*ho=0.925*1.183*1.43*2717.543*1095.000=4655.743kN> 丫 o*Vy=3984.644kN 承台斜截面受剪满足规范要求九、承台受弯计算1. 确定单桩最大竖向力Nmax=max(N1, N2, N3)=2001.509kNM=Nmax*(A-(sqrt(3)/4)*bc)/3 =2001.509*(1.800-(sqrt(3)/4)*0.500)/3=1056.459kN*m3.计算系数C30 混凝土a 1=1.0a s=M/( a 1*fc_b*By*ho*ho) =1056.459/(1.0*14.3*3.000*1.095*1.095*1000) =0.0214.相对界限受压区高度E b=B 1/(1+fy/Es/ & cu)=0.518E =1-sqrt(1-2 a s)=0.021 < E b=0.5185.纵向受拉钢筋Asx=Asy=a 1*fc_b*By*ho* E /fy=1.0*14.3*3000.000*1095.000*0.021/3602=2708mm 2最小配筋面积 :B=|y1|+C=|-519.6|+600=1119.6mmAsxmin=Asymin=p min*B*H =0.200%*1119.6*12502=2799mmI I - 2Asx<Asxmin,取 Asx=Asxmin=2799mmAsy<Asymin,取 Asx=Asymin=2799mm6.选择Asx钢筋选择钢筋9^ 20,实配面积为2827mi n/m7.选择Asy钢筋选择钢筋9磨20,实配面积为2827mmm十、柱对承台的局部受压验算1.因为承台的混凝土强度等级小于柱的混凝土强度等级，验算柱下承台顶面的局部受压承载力。