八桩桩基承台计算.doc

结构构件计算书八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 (GB50007-2002)混凝土结构设计规范 (GB50010-2002)建筑桩基技术规范 (JGJ94-94)二、示意图三、计算信息承台类型: 八桩承台计算类型: 验算截面尺寸构件编号: CT-81. 几何参数矩形柱宽bc=600mm矩形柱高hc=600mm方桩边长ls=250mm承台根部高度H=850mm承台端部高度h=850mmx方向桩中心距A=700mmy方向桩中心距B=700mm承台边缘至边桩中心距 C=350mm2. 材料信息柱混凝土强度等级: C30 ft_c=1.43N/mm2,fc_c=14.3N/mm2承台混凝土强度等级:C30 ft_b=1.43N/mm2,fc_b=14.3N/mm2桩混凝土强度等级: C30 ft_p=1.43N/mm2,fc_p=14.3N/mm2承台钢筋级别: HRB335 fy=300N/mm23. 计算信息结构重要性系数: o=1.0 纵筋合力点至近边距离:as=40mm4. 作用在承台顶部荷载基本组合值F=3680.000kNMx=-17.000kN*mMy=-52.000kN*mVx=10.000kNVy=15.000kN四、计算参数1. 承台总长 Bx=C+4*A+C=0.350+4*0.700+0.350=3.500m2. 承台总宽 By=C+2*B+C=0.350+2*0.700+0.350=2.100m3. 承台根部截面有效高度 ho=H-as=0.850-0.040=0.810mho1=h-as=0.850-0.040=0.810mh2=H-h=0.850-0.850=0.000m4. 方桩换算截面宽度 bp=ls=0.250m五、内力计算1. 各桩编号及定位座标如上图所示:1号桩 (x1=-2*A=-1.400m, y1=-B=-0.700m)2号桩 (x2=0, y2=-B=-0.700m)3号桩 (x3=2*A=1.400m, y3=-B=-0.700m)4号桩 (x4=2*A=1.400m, y4=B=0.700m)5号桩 (x5=0, y5=B=0.700m)6号桩 (x6=-2*A=-1.400m, y6=B=0.700m)7号桩 (x7=-A=-0.700m, y7=0)8号桩 (x8=A=0.700m, y8=0)2. 各桩净反力设计值, 计算公式:【8.5.3-2】xi=(x12)*4+(x72)*2=8.820myi=(y12)*6=2.940mNi=F/n-Mx*yi/yi2+My*xi/xi2+Vx*H*xi/xi2-Vy*H*y1/yi2N1=3680.000/8-(-17.000)*(-0.700)/2.940+(-52.000)*(-1.400)/8.820 +10.000*0.850*(-1.400)/8.820-15.000*0.850*(-0.700)/2.940 =459.821kNN2=3680.000/8-(-17.000)*(-0.700)/2.940+(-52.000)*0.000/8.820 +10.000*0.850*0.000/8.820-15.000*0.850*(-0.700)/2.940 =452.917kNN3=3680.000/8-(-17.000)*(-0.700)/2.940+(-52.000)*1.400/8.820 +10.000*0.850*1.400/8.820-15.000*0.850*(-0.700)/2.940 =446.012kNN4=3680.000/8-(-17.000)*0.700/2.940+(-52.000)*1.400/8.820 +10.000*0.850*1.400/8.820-15.000*0.850*0.700/2.940 =460.179kNN5=3680.000/8-(-17.000)*0.700/2.940+(-52.000)*0.000/8.820 +10.000*0.850*0.000/8.820-15.000*0.850*0.700/2.940 =467.083kNN6=3680.000/8-(-17.000)*0.700/2.940+(-52.000)*(-1.400)/8.820 +10.000*0.850*(-1.400)/8.820-15.000*0.850*0.700/2.940 =473.988kNN7=3680.000/8-(-17.000)*0.000/2.940+(-52.000)*(-0.700)/8.820 +10.000*0.850*(-0.700)/8.820-15.000*0.850*0.000/2.940 =463.452kNN8=3680.000/8-(-17.000)*0.000/2.940+(-52.000)*0.700/8.820 +10.000*0.850*0.700/8.820-15.000*0.850*0.000/2.940 =456.548kN六、柱对承台的冲切验算 【8.5.17-1】1. Ni=N7+N8=920.000kN 当 (A+bp/2.0)H 时2. 因为 (A+bp/2)=0.700+0.250/2=0.825ho, 所以 ox=ho=0.810moy=B-hc/2-bp/2=0.700-0.600/2-0.250/2=0.275m3. ox=ox/ho=0.810/0.810=1.000 oy=oy/ho=0.275/0.810=0.3404. ox=0.84/(ox+0.2)=0.84/(1.000+0.2)=0.700 oy=0.84/(oy+0.2)=0.84/(0.340+0.2)=1.5575. 因 H=0.850m 所以 hp=0.996o*Fl=o*(F-Ni)=1.0*(3680.000-920.000)=2760.00kN2*ox*(hc+oy)+oy*(bc+ox)*hp*ft_b*ho=2*0.700*(600+275)+1.557*(600+810)*0.996*1.43*810=6477.54kNo*Fl=2760.00kN柱对承台的冲切满足规范要求七、角桩对承台的冲切验算 【8.5.17-5】1. Nl=max(N1, N3, N4, N6)=473.988kN2. a1x=2*A-bc/2-bp/2=2*0.700-0.600/2-0.250/2=0.975m因为 a1xho1 所以 a1x=ho1=0.810m a1y=B-hc/2-bp/2=0.700-0.600/2-0.250/2=0.275m3. 1x=a1x/ho1=0.810/0.810=1.000 1y=a1y/ho1=0.275/0.810=0.3404. 1x=0.56/(1x+0.2)=0.56/(1.000+0.2)=0.467 1y=0.56/(1y+0.2)=0.56/(0.340+0.2)=1.038 C1=C+1/2*bp=0.350+0.250/2=0.475m C2=C+1/2*bp=0.350+0.250/2=0.475m5. 因 h=0.850m 所以 hp=0.996 o*Nl=1.0*473.988=473.988kN 1x*(C2+a1y/2.0)+1y*(C1+a1x/2)*hp*ft_b*ho1 =0.467*(475+275/2)+1.038*(475+810/2)*0.996*1.43*810 =1383.316kNo*Nl=473.988kN角桩对承台的冲切满足规范要求八、承台斜截面受剪验算 【8.5.18-1】1. 计算承台计算截面处的计算宽度 bx1=Bx=C+4*A+C=0.350+4*0.700+0.350=3.500m bx2=bc=0.600m bxo=1-0.5*h2/ho*(1-bx2/bx1)*bx1 =1-0.5*0.000/0.810*(1-0.600/3.500)*3.500 =3.500m by1=By=C+2*B+C=0.350+2*0.700+0.350=2.100m by2=hc=0.600m byo=1-0.5*h2/ho*(1-by2/by1)*by1 =1-0.5*0.000/0.810*(1-0.600/2.100)*2.100 =2.100m2.计算剪切系数因 0.800ho=0.810m2.000m,hs=(0.800/0.810)1/4=0.997 ax1=2*A-bc/2-bp/2=2*0.700-0.600/2-0.250/2=0.975m x1=ax1/ho=0.975/0.810=1.204 x1=1.75/(x1+1.0)=1.75/(1.204+1.0)=0.794 ax2=A-bc/2-bp/2=0.700-0.600/2-0.250/2=0.275m x2=ax2/ho=0.275/0.810=0.340 x2=1.75/(x2+1.0)=1.75/(0.340+1.0)=1.306 ay=B-hc/2-bp/2=0.700-0.600/2-0.250/2=0.275m y=ay/ho=0.275/0.810=0.340 y=1.75/(y+1.0)=1.75/(0.340+1.0)=1.3063. 计算承台底部最大剪力【8.5.18-1】 因为 N16=N1+N6=459.821+473.988=933.810kNN34=N3+N4=446.012+460.179=906.190kN 所以 Vx1=max(|N16|, |N34|)=933.810kN 因为 N167=N1+N6+N7=459.821+473.988+463.452=1397.262kNN348=N3+N4+N8=446.012+460.179+456.548=1362.738kN 所以 Vx2=max(|N167|, |N348|)=1397.262kN 因为 N123=N1+N2+N3=459.821+452.917+446.012=1358.750kNN456=N4+N5+N6=460.179+467.083+473.988=1401.250kN 所以 Vy=max(N123, N456)=1401.250kN 3. 计算承台底部最大剪力【8.5.18-1】 验算x1截面承载力 o*Vx1=1.0*933.810=933.810kN hs*x1*ft_b*byo*ho=0.997*0.794*1.43*2100*810=1925.646kNo*Vx1=933.810kN 承台斜截面X1受剪满足规范要求验算x2截面承载力 o*Vx2=1.0*1397.262=1397.262kN hs*x2*ft_b*byo*ho=0.997*1.306*1.43*2100*810=3167.998kNo*Vx2=1397.262kN 承台斜截面X2受剪满足规范要求验算y截面承载力 o*Vy=1.0*1401.250=1401.250kN hs*y*ft_b*bxo*ho=0.997*1.306*1.43*3500*810 =5279.997kNo*Vy=1401.250kN 承台斜截面Y受剪满足规范要求九、承台受弯计算 【8.5.16-1】【8.5.16-2】1. 承台底部弯矩最大值 【8.5.16-1】【8.5.16-2】因为 Mdx16=(N1+N6)*(2*A-1/2*bc) =(459.821+473.988)*(2*0.700-1/2*0.600) =1027.19kN*m Mdx34=(N3+N4)*(2*A-1/2*bc) =(446.012+460.179)*(2*0.700-1/2*0.600) =996.81kN*m Mdx7=N7*(A-1/2*bc) =463.452*(0.700-1/2*0.600) =185.38kN*m Mdx8=N8*(A-1/2*bc) =456.548*(0.700-1/2*0.600) =182.62kN*m所以 Mx=max(|Mdx16+Mdx7|, |Mdx8+Mdx34|)=max(|1212.57|,|1179.43|)=1212.57kN*m因为 Mdy123=(N1+N2+N3)*(B-1/2*hc) =(459.821+452.917+446.012)*(0.700-1/2*0.600) =543.50kN*m Mdy456=(N4+N5+N6)*(B-1/2*hc) =(460.179+467.083+473.988)*(0.700-1/2*0.600) =560.50kN*m所以 My=max(|Mdy123|, |Mdy456|)=max(|543.50|,|560.50|)=560.50kN*m2. 计算配筋面积Asx=o*Mx/(0.9*ho*fy)=1.0*1212.57*106/(0.9*810*300)=5544.5mm2Asx1=Asx/By=5544.5/2=2640mm2/mAsy=o*My/(0.9*ho*fy)=1.0*560.50*106/(0.9*810.000*300)=2562.9mm2Asy1=Asy/Bx=2562.9/4=732mm2/m3. 计算最小配筋率受弯最小配筋率为 min=0.150%4. 承台最小配筋面积As1min=min*H*1000=0.15