pkpm桩基承台计算.docx

CT5 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 (GB50010-2010)建筑桩基技术规范 (JGJ 942008)二、示意图三、计算信息承台类型: 三桩承台计算类型: 验算截面尺寸构件编号: CT-11. 几何参数矩形柱宽bc=450mm矩形柱高hc=600mm圆桩直径d=500mm承台根部高度H=1200mmx方向桩中心距A=1750mmy方向桩中心距B=1750mm承台边缘至边桩中心距 C=500mm2. 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: C80 ft_p=2.22N/mm2,fc_p=35.9N/mm2承台钢筋级别: HRB400 fy=360N/mm23. 计算信息结构重要性系数: o=1.1 纵筋合力点至近边距离:as=150mm4. 作用在承台顶部荷载基本组合值F=3244.000kNMx=57.700kN*mMy=103.500kN*mVx=69.800kNVy=-38.800kN四、计算参数1. 承台总长 Bx=C+A+C=0.500+1.750+0.500=2.750m2. 承台总宽 By=C+B+C=0.500+1.750+0.500=2.750m3. 承台根部截面有效高度 ho=H-as=1.200-0.150=1.050m4. 圆桩换算截面宽度 bp=0.8*d=0.8*0.500=0.400m五、内力计算1. 各桩编号及定位座标如上图所示:1=arccos(0.5*A/B)=1.0472=2*arcsin(0.5*A/B)=1.0471号桩 (x1=-A/2=-0.875m, y1=-B*cos(0.5*2)/3=-0.505m)2号桩 (x2=A/2=0.875m, y2=-B*cos(0.5*2)/3=-0.505m)3号桩 (x3=0, y3=B*cos(0.5*2)*2/3=1.010m)2. 各桩净反力设计值, 计算公式:【8.5.3-2】xi=x12*2=1.531myi=y12*2+y32=1.531mNi=F/n-Mx*yi/yi2+My*xi/xi2+Vx*H*xi/xi2-Vy*H*y1/yi2N1=3244.000/3-57.700*(-0.505)/1.531+103.500*(-0.875)/1.531 +69.800*1.200*(-0.875)/1.531-38.800*1.200*(-0.505)/1.531 =1008.724kNN2=3244.000/3-57.700*(-0.505)/1.531+103.500*0.875/1.531 +69.800*1.200*0.875/1.531-38.800*1.200*(-0.505)/1.531 =1222.736kNN3=3244.000/3-57.700*1.010/1.531+103.500*0.000/1.531 +69.800*1.200*0.000/1.531-38.800*1.200*1.010/1.531 =1012.540kN六、柱对承台的冲切验算 【8.5.17-1】1. Ni=0=0.000kN ho1=h-as=1.200-0.150=1.050m2. ox=A/2-bc/2-bp/2=1.750/2-1/2*0.450-1/2*0.400=0.450moy12=y2-hc/2-bp/2=0.505-0.600/2-0.400/2=0.005moy3=y3-hc/2-bp/2=1.010-0.600/2-0.400/2=0.510m3. ox=ox/ho1=0.450/1.050=0.429 oy12=oy12/ho1=0.210/1.050=0.200 oy3=oy3/ho1=0.510/1.050=0.4864. ox=0.84/(ox+0.2)=0.84/(0.429+0.2)=1.336 oy12=0.84/(oy12+0.2)=0.84/(0.200+0.2)=2.100 oy3=0.84/(oy3+0.2)=0.84/(0.486+0.2)=1.2246. 计算冲切临界截面周长AD=0.5*A+C/tan(0.5*1)=0.5*1.750+0.500/tan(0.5*1.047)=1.741mCD=AD*tan(1)=1.741*tan(1.047)=3.016mAE=C/tan(0.5*1)=0.500/tan(0.5*1.047)=0.866m6.1 计算Umx1Umx1=bc+ox=0.450+0.450=0.900m6.2 计算Umx2Umx2=2*AD*(CD-C-|y1|-|y3|+0.5*bp)/CD=2*1.741*(3.016-0.500-|-0.505|-|1.010|+0.5*0.400)/3.016=1.386m因Umx2Umx1,取Umx2=Umx1=0.900mUmy=hc+oy12+oy3=0.600+0.210+0.510=1.320m因 Umy(C*tan(1)/tan(0.5*1)-C-0.5*bpUmy=(C*tan(1)/tan(0.5*1)-C-0.5*bp =(0.500*tan(1.047)/tan(0.5*1.047)-0.500-0.5*0.400 =0.800m7.计算冲切抗力 因 H=1.200m 所以 hp=0.967o*Fl=o*(F-Ni)=1.1*(3244.000-0.000)=3568.40kN ox*2*Umy+oy12*Umx1+oy3*Umx2*hp*ft_b*ho =1.336*2*0.800+2.100*0.900+1.224*0.900*0.967*1.43*1.050*1000 =7446.122kNo*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 【8.5.17-5】计算公式:【8.5.17-5】1. Nl=max(N1,N2)=1222.736kN ho1=h-as=1.200-0.150=1.050m2. a11=(A-bc-bp)/2=(1.750-0.450-0.400)/2=0.450m a12=(y3-(hcd)*0.5)*cos(0.5*2)=(1.010-(0.600-0.400)*0.5)*cos(0.5*1.047)=0.442m 11=a11/ho=0.450/1.050=0.429 11=0.56/(11+0.2)=0.56/(0.429+0.2)=0.891 C1=(C/tan(0.5*1)+0.5*bp=(C/tan(0.5*1.047)+0.5*0.400=1.066m 12=a12/ho=0.442/1.050=0.421 12=0.56/(12+0.2)=0.56/(0.421+0.2)=0.902 C2=(CD-C-|y1|-y3+0.5d)*cos(0.5*2)=(3.016-0.500-|-0.505|-1.010+0.5*1.047)*cos(0.5*0.400)=1.039m3. 因 h=1.200m 所以 hp=0.967 o*Nl=1.1*1222.736=1345.010kN 11*(2*C1+a11)*(tan(0.5*1)*hp*ft_b*ho =0.891*(2*1066.025+450.000)*(tan(0.5*1.047)*0.967*1.43*1050.000 =1927.701kNo*Nl=1345.010kN 底部角桩对承台的冲切满足规范要求 o*N3=1.1*1012.540=1113.794kN 12*(2*C2+a12)*(tan(0.5*2)*hp*ft_b*ho =0.902*(2*1039.230+441.987)*(tan(0.5*1.047)*0.967*1.43*1050.000*1000 =1904.835kNo*N3=1113.794kN 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 【8.5.18-1】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=1.050m2.000m,hs=(0.800/1.050)1/4=0.934 ay=|y3|-0.5*hc-0.5*bp=|1.010|-0.5*0.600-0.5*0.400=0.510 y=ay/ho=0.510/1.050=0.486 y=1.75/(y+1.0)=1.75/(0.486+1.0)=1.1783. 计算承台底部最大剪力【8.5.18-1】 bxo=A*(2/3+hc/2/sqrt(B2-(A/2)2)+2*C =1.750*(2/3+0.600/2/sqrt(1.7502-(1.750/2)2)+2*0.500 =2.513m o*Vy=1.1*2231.460=2454.606kN hs*y*ft_b*bxo*ho=0.934*1.178*1.43*2513.077*1050.000 =4151.528kNo*Vy=2454.606kN 承台斜截面受剪满足规范要求九、承台受弯计算 【8.5.16-1】【8.5.16-2】计算公式:【8.5.16-1.2】1. 确定单桩最大竖向力Nmax=max(N1, N2, N3)=1222.736kN2. 承台底部弯矩最大值 【8.5.16-1】【8.5.16-2】M=Nmax*(A-(sqrt(3)/4)*bc)/3 =1222.736*(1.750-(sqrt(3)/4)*0.450)/3 =633.844kN*m3.计算系数C30混凝土 1=1.0 s=M/(1*fc_b*By*ho*ho) =633.844/(1.0*14.3*2.750*1.050*1.050*1000) =0.0154.相对界限受压区高度 b=1/(1+fy/Es/cu)=0.518 =1-sqrt(1-2s)=0.015b=0.5185.纵向受拉钢筋 Asx=Asy=1*fc_b*By*ho*/fy =1.0*14.3*2750.000*1050.000*0.015/360 =1689mm2 最小配筋面积: B=|y1|+C=|-505.2|+500=1005.2mm Asxmin=Asymin=min*B*H =0.200%*1005.2*1200 =2412mm2 AsxAsxmin,取Asx=Asxmin=2412mm2 AsyAsymin,取Asx=Asymin=2412mm26. 选择Asx钢筋选择钢筋525, 实配面积为2454mm2/m。7. 选择Asy钢筋计算钢筋面积超出一般选筋范围，请用户自行选择配筋方案。十、柱