三桩桩基承台计算.doc

结构构件计算书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 (GB50007-2002)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-31. 几何参数矩形柱宽bc=400mm矩形柱高hc=400mm圆桩直径d=500mm承台根部高度H=1000mmx方向桩中心距A=2000mmy方向桩中心距B=2000mm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: C30 ft_p=1.43N/mm2,fc_p=14.3N/mm2承台钢筋级别: HRB400 fy=360N/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=2550.000kNMx=0.000kN*mMy=0.000kN*mVx=0.000kNVy=0.000kN四、计算参数1. 承台总长 Bx=C+A+C=0.500+2.000+0.500=3.000m2. 承台总宽 By=C+B+C=0.500+2.000+0.500=3.000m3. 承台根部截面有效高度 ho=H-as=1.000-0.040=0.960m4. 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=-1.000m, y1=-B*cos(0.5*2)/3=-0.577m)2号桩 (x2=A/2=1.000m, y2=-B*cos(0.5*2)/3=-0.577m)3号桩 (x3=0, y3=B*cos(0.5*2)*2/3=1.155m)2. 各桩净反力设计值, 计算公式:【8.5.3-2】xi=x12*2=2.000myi=y12*2+y32=2.000mNi=F/n-Mx*yi/yi2+My*xi/xi2+Vx*H*xi/xi2-Vy*H*y1/yi2N1=2550.000/3-0.000*(-0.577)/2.000+0.000*(-1.000)/2.000 +0.000*1.000*(-1.000)/2.000-0.000*1.000*(-0.577)/2.000 =850.000kNN2=2550.000/3-0.000*(-0.577)/2.000+0.000*1.000/2.000 +0.000*1.000*1.000/2.000-0.000*1.000*(-0.577)/2.000 =850.000kNN3=2550.000/3-0.000*1.155/2.000+0.000*0.000/2.000 +0.000*1.000*0.000/2.000-0.000*1.000*1.155/2.000 =850.000kN六、柱对承台的冲切验算 【8.5.17-1】1. Ni=0=0.000kN ho1=h-as=1.000-0.040=0.960m2. ox=A/2-bc/2-bp/2=2.000/2-1/2*0.400-1/2*0.400=0.600moy12=y2-hc/2-bp/2=0.577-0.400/2-0.400/2=0.177moy3=y3-hc/2-bp/2=1.155-0.400/2-0.400/2=0.755m3. ox=ox/ho1=0.600/0.960=0.625 oy12=oy12/ho1=0.192/0.960=0.200 oy3=oy3/ho1=0.755/0.960=0.7864. ox=0.84/(ox+0.2)=0.84/(0.625+0.2)=1.018 oy12=0.84/(oy12+0.2)=0.84/(0.200+0.2)=2.100 oy3=0.84/(oy3+0.2)=0.84/(0.786+0.2)=0.8526. 计算冲切临界截面周长AD=0.5*A+C/tan(0.5*1)=0.5*2.000+0.500/tan(0.5*1.047)=1.866mCD=AD*tan(1)=1.866*tan(1.047)=3.232mAE=C/tan(0.5*1)=0.500/tan(0.5*1.047)=0.866m6.1 计算Umx1Umx1=bc+ox=0.400+0.600=1.000m6.2 计算Umx2Umx2=2*AD*(CD-C-|y1|-|y3|+0.5*bp)/CD=2*1.866*(3.232-0.500-|-0.577|-|1.155|+0.5*0.400)/3.232=1.386m因Umx2Umx1,取Umx2=Umx1=1.000mUmy=hc+oy12+oy3=0.400+0.192+0.755=1.347m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=1.000m 所以 hp=0.983o*Fl=o*(F-Ni)=1.0*(2550.000-0.000)=2550.00kN ox*2*Umy+oy12*Umx1+oy3*Umx2*hp*ft_b*ho =1.018*2*0.800+2.100*1.000+0.852*1.000*0.983*1.43*0.960*1000 =6183.837kNo*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)=850.000kN ho1=h-as=1.000-0.040=0.960m2. a11=(A-bc-bp)/2=(2.000-0.400-0.400)/2=0.600m a12=(y3-(hcd)*0.5)*cos(0.5*2)=(1.155-(0.400-0.400)*0.5)*cos(0.5*1.047)=0.654m 11=a11/ho=0.600/0.960=0.625 11=0.56/(11+0.2)=0.56/(0.625+0.2)=0.679 C1=(C/tan(0.5*1)+0.5*bp=(C/tan(0.5*1.047)+0.5*0.400=1.066m 12=a12/ho=0.654/0.960=0.681 12=0.56/(12+0.2)=0.56/(0.681+0.2)=0.636 C2=(CD-C-|y1|-y3+0.5d)*cos(0.5*2)=(3.232-0.500-|-0.577|-1.155+0.5*1.047)*cos(0.5*0.400)=1.039m3. 因 h=1.000m 所以 hp=0.983 o*Nl=1.0*850.000=850.000kN 11*(2*C1+a11)*(tan(0.5*1)*hp*ft_b*ho =0.679*(2*1066.025+600.000)*(tan(0.5*1.047)*0.983*1.43*960.000 =1445.341kNo*Nl=850.000kN 底部角桩对承台的冲切满足规范要求 o*N3=1.0*850.000=850.000kN 12*(2*C2+a12)*(tan(0.5*2)*hp*ft_b*ho =0.636*(2*1039.230+653.590)*(tan(0.5*1.047)*0.983*1.43*960.000*1000 =1353.741kNo*N3=850.000kN 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=0.960m2.000m,hs=(0.800/0.960)1/4=0.955 ay=|y3|-0.5*hc-0.5*bp=|1.155|-0.5*0.400-0.5*0.400=0.755 y=ay/ho=0.755/0.960=0.786 y=1.75/(y+1.0)=1.75/(0.786+1.0)=0.9803. 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 =2.000*(2/3+0.400/2/sqrt(2.0002-(2.000/2)2)+2*0.500 =2.564m o*Vy=1.0*1700.000=1700.000kN hs*y*ft_b*bxo*ho=0.955*0.980*1.43*2564.273*960.000 =3295.318kNo*Vy=1700.000kN 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)=850.000kN2. 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 =850.000*(2.000-(sqrt(3)/4)*0.400)/3 =517.592kN*m3.计算系数C30混凝土 1=1.0 s=M/(1*fc_b*By*ho*ho) =517.592/(1.0*14.3*3.000*0.960*0.960*1000) =0.0134.相对界限受压区高度 b=1/(1+fy/Es/cu)=0.518 =1-sqrt(1-2s)=0.013b=0.5185.纵向受拉钢筋 Asx=Asy=1*fc_b*By*ho*/fy =1.0*14.3*3000.000*960.000*0.013/360 =1508mm2 最小配筋面积: B=|y1|+C=|-577.4|+500=1077.4mm Asxmin=Asymin=min*B*H =0.150%*1077.4*1000 =1616mm2 AsxAsxmin,取Asx=Asxmin=1616mm2 AsyAsymin,取As