1、階梯基礎計算（j-1）項目名稱_日 期_設 計 者_校 對 者_一、設計依據建筑地基基礎設計規范 (gb50007-2002)混凝土結構設計規范 (gb50010-2010)二、示意圖三、計算信息構件編號: jc-1計算類型: 驗算截面尺寸1. 幾何參數臺階數n=2矩形柱寬bc=700mm矩形柱高hc=900mm基礎高度h1=300mm基礎高度h2=400mm一階長度 b1=250mmb2=300mm 一階寬度 a1=300mma2=300mm二階長度 b3=250mmb4=300mm 二階寬度 a3=300mma4=300mm2. 材料信息基礎混凝土等級:c30ft_b=1.43n/mm2f

2、c_b=14.3n/mm2柱混凝土等級:c30ft_c=1.43n/mm2fc_c=14.3n/mm2鋼筋級別:hrb335 fy=300n/mm23. 計算信息結構重要性系數: o=1.0 基礎埋深: dh=1.500m縱筋合力點至近邊距離:as=40mm基礎及其上覆土的平均容重:=20.000kn/m3最小配筋率:min=0.100%fgk=176.780knfqk=0.000knmgxk=141.340kn*mmqxk=0.000kn*mmgyk=0.000kn*mmqyk=0.000kn*mvgxk=54.380knvqxk=0.000knvgyk=0.000knvqyk=0.000k

3、n永久荷載分項系數rg=1.20可變荷載分項系數rq=1.40fk=fgk+fqk=176.780+(0.000)=176.780knmxk=mgxk+fgk*(b2-b1)/2+mqxk+fqk*(b2-b1)/2 =141.340+176.780*(0.900-0.900)/2+(0.000)+0.000*(0.900-0.900)/2 =141.340kn*mmyk=mgyk+fgk*(a2-a1)/2+mqyk+fqk*(a2-a1)/2 =0.000+176.780*(1.050-1.050)/2+(0.000)+0.000*(1.050-1.050)/2 =0.000kn*mvxk

4、=vgxk+vqxk=54.380+(0.000)=54.380knvyk=vgyk+vqyk=0.000+(0.000)=0.000knf1=rg*fgk+rq*fqk=1.20*(176.780)+1.40*(0.000)=212.136knmx1=rg*(mgxk+fgk*(b2-b1)/2)+rq*(mqxk+fqk*(b2-b1)/2) =1.20*(141.340+176.780*(0.900-0.900)/2)+1.40*(0.000+0.000*(0.900-0.900)/2) =169.608kn*mmy1=rg*(mgyk+fgk*(a2-a1)/2)+rq*(mqyk+f

5、qk*(a2-a1)/2) =1.20*(0.000+176.780*(1.050-1.050)/2)+1.40*(0.000+0.000*(1.050-1.050)/2) =0.000kn*mvx1=rg*vgxk+rq*vqxk=1.20*(54.380)+1.40*(0.000)=65.256knvy1=rg*vgyk+rq*vqyk=1.20*(0.000)+1.40*(0.000)=0.000knf2=1.35*fk=1.35*176.780=238.653knmx2=1.35*mxk=1.35*141.340=190.809kn*mmy2=1.35*myk=1.35*(0.000)

6、=0.000kn*mvx2=1.35*vxk=1.35*54.380=73.413knvy2=1.35*vyk=1.35*(0.000)=0.000knf=max(|f1|,|f2|)=max(|212.136|,|238.653|)=238.653knmx=max(|mx1|,|mx2|)=max(|169.608|,|190.809|)=190.809kn*mmy=max(|my1|,|my2|)=max(|0.000|,|0.000|)=0.000kn*mvx=max(|vx1|,|vx2|)=max(|65.256|,|73.413|)=73.413knvy=max(|vy1|,|vy

7、2|)=max(|0.000|,|0.000|)=0.000kn5. 修正后的地基承載力特征值fa=200.000kpa 四、計算參數1. 基礎總長 bx=b1+b2+b3+b4+bc=0.250+0.300+0.250+0.300+0.700=1.800m2. 基礎總寬 by=a1+a2+a3+a4+hc=0.300+0.300+0.300+0.300+0.900=2.100ma1=a1+a2+hc/2=0.300+0.300+0.900/2=1.050m a2=a3+a4+hc/2=0.300+0.300+0.900/2=1.050mb1=b1+b2+bc/2=0.250+0.300+0.

8、700/2=0.900m b2=b3+b4+bc/2=0.250+0.300+0.700/2=0.900m3. 基礎總高 h=h1+h2=0.300+0.400=0.700m4. 底板配筋計算高度 ho=h1+h2-as=0.300+0.400-0.040=0.660m5. 基礎底面積 a=bx*by=1.800*2.100=3.780m26. gk=*bx*by*dh=20.000*1.800*2.100*1.500=113.400kng=1.35*gk=1.35*113.400=153.090kn五、計算作用在基礎底部彎矩值mdxk=mxk-vyk*h=141.340-0.000*0.70

9、0=141.340kn*mmdyk=myk+vxk*h=0.000+54.380*0.700=38.066kn*mmdx=mx-vy*h=190.809-0.000*0.700=190.809kn*mmdy=my+vx*h=0.000+73.413*0.700=51.389kn*m六、驗算地基承載力1. 驗算軸心荷載作用下地基承載力pk=(fk+gk)/a=(176.780+113.400)/3.780=76.767kpa【5.2.1-2】因o*pk=1.0*76.767=76.767kpafa=200.000kpa軸心荷載作用下地基承載力滿足要求2. 驗算偏心荷載作用下的地基承載力exk=m

10、dyk/(fk+gk)=38.066/(176.780+113.400)=0.131m因 |exk| bx/6=0.300mx方向小偏心,由公式【5.2.2-2】和【5.2.2-3】推導pkmax_x=(fk+gk)/a+6*|mdyk|/(bx2*by) =(176.780+113.400)/3.780+6*|38.066|/(1.8002*2.100) =110.335kpapkmin_x=(fk+gk)/a-6*|mdyk|/(bx2*by) =(176.780+113.400)/3.780-6*|38.066|/(1.8002*2.100) =43.199kpaeyk=mdxk/(fk

11、+gk)=141.340/(176.780+113.400)=0.487m因 |eyk| by/6=0.350my方向大偏心, 由公式【8.2.2-2】推導ayk=by/2-|eyk|=2.100/2-|0.487|=0.563mpkmax_y=2*(fk+gk)/(3*bx*ayk) =2*(176.780+113.400)/(3*1.800*0.563) =190.921kpapkmin_y=(fk+gk)/a-6*|mdxk|/(by2*bx) =(176.780+113.400)/3.780-6*|141.340|/(2.1002*1.800) =-30.066kpa3. 確定基礎底面

12、反力設計值pkmax=(pkmax_x-pk)+(pkmax_y-pk)+pk =(110.335-76.767)+(190.921-76.767)+76.767 =224.489kpao*pkmax=1.0*224.489=224.489kpa1.2*fa=1.2*200.000=240.000kpa偏心荷載作用下地基承載力滿足要求七、基礎沖切驗算1. 計算基礎底面反力設計值1.1 計算x方向基礎底面反力設計值ex=mdy/(f+g)=51.389/(238.653+153.090)=0.131m因 ex bx/6.0=0.300mx方向小偏心pmax_x=(f+g)/a+6*|mdy|/(

13、bx2*by) =(238.653+153.090)/3.780+6*|51.389|/(1.8002*2.100) =148.952kpapmin_x=(f+g)/a-6*|mdy|/(bx2*by) =(238.653+153.090)/3.780-6*|51.389|/(1.8002*2.100) =58.319kpa1.2 計算y方向基礎底面反力設計值ey=mdx/(f+g)=190.809/(238.653+153.090)=0.487m因 ey by/6=0.350y方向大偏心, 由公式【8.2.2-2】推導ay=by/2-|ey|=2.100/2-|0.487|=0.563mpm

14、ax_y=2*(f+g)/(3*bx*ay) =2*(238.653+153.090)/(3*1.800*0.563) =257.744kpapmin_y=01.3 因 mdx0 mdy0 pmax=pmax_x+pmax_y-(f+g)/a=148.952+257.744-(238.653+153.090)/3.780=303.061kpa1.4 計算地基凈反力極值pjmax=pmax-g/a=303.061-153.090/3.780=262.561kpapjmax_x=pmax_x-g/a=148.952-153.090/3.780=108.452kpapjmax_y=pmax_y-g/

15、a=257.744-153.090/3.780=217.244kpa2. 驗算柱邊沖切yh=h1+h2=0.700m, yb=bc=0.700m, yl=hc=0.900myb1=b1=0.900m, yb2=b2=0.900m, yl1=a1=1.050m, yl2=a2=1.050myho=yh-as=0.660m因 (yb+2*yho)bx) 并且 (yl+2*yho)by)基礎底面處邊緣均位于沖切錐體以內, 不用驗算柱對基礎的沖切3. 驗算h2處沖切yh=h2=0.400myb=bc+b2+b4=1.300myl=hc+a2+a4=1.500myb1=b1=0.900m, yb2=b2

16、=0.900m, yl1=a1=1.050m, yl2=a2=1.050myho=yh-as=0.360m因 (yb+2*yho)bx) 并且 (yl+2*yho)by)基礎底面處邊緣均位于沖切錐體以內, 不用驗算柱對基礎的沖切八、柱下基礎的局部受壓驗算因為基礎的混凝土強度等級大于等于柱的混凝土強度等級，所以不用驗算柱下擴展基礎頂面的局部受壓承載力。九、基礎受彎計算1. 因mdx0 , mdy0 此基礎為雙向受彎2. 計算i-i截面彎矩因 ex bx/6=0.300m x方向小偏心a=(bx-bc)/2=(1.800-0.700)/2=0.550mpj1=(bx-a)*(pmax_x-pmin

17、_x)/bx)+pmin_x-g/a =(1.800-0.550)*(148.952-58.319)/1.800)+58.319-153.090/3.780 =80.759kpa因 ex by/6=0.350m y方向大偏心a=(by-hc)/2=(2.100-0.900)/2=0.600may=by/2-ey=2.100/2-0.487=0.563mpj2=(pmax_y*(3*ay-a)/(3*ay)-g/a=(257.744*(3*0.563-0.600)/(3*0.563)-153.090/3.780=125.671kpax=1.062y=1.085mi_1=1/48*x*(bx-bc

18、)2*(2*by+hc)*(pj1+pjmax_x)=1/48*1.062*(1.800-0.700)2*(2*2.100+0.900)*(80.759+108.452)=25.83kn*mmii_1=1/48*y*(by-hc)2*(2*bx+bc)*(pj2+pjmax_y)=1/48*1.085*(2.100-0.900)2*(2*1.800+0.700)*(125.671+217.244)=47.98kn*m3. 計算ii-ii截面彎矩因 x方向小偏心a=(bx-bc-b2-b4)/2=(1.800-0.700-0.300-0.300)/2=0.250mpj1=(bx-a)*(pmax

19、_x-pmin_x)/bx)+pmin_x-g/a=(1.800-0.250)*(148.952-58.319)/1.800)+58.319-153.090/3.780=95.864kpa因 y方向大偏心a=(by-hc-a2-a4)/2=(2.100-0.900-0.300-0.300)/2=0.300may=by/2-ey=2.100/2-0.487=0.563mpj2=(pmax_y*(3*ay-a)/(3*ay)-g/a=(257.744*(3*0.563-0.300)/(3*0.563)-153.090/3.780=171.457kpax=1.023y=1.035mi_2=1/48*

20、x*(bx-bc-b2-b4)2*(2*by+hc+a2+a4)*(pj1+pjmax_x)=1/48*1.023*(1.800-0.700-0.300-0.300)2*(2*2.100+0.900+0.300+0.300)*(95.864+108.452)=6.20kn*mmii_2=1/48*y*(by-hc-a2-a4)2*(2*bx+bc+b2+b4)*(pj2+pjmax_y)=1/48*1.035*(2.100-0.900-0.300-0.300)2*(2*1.800+0.700+0.300+0.300)*(171.457+108.452)=14.78kn*m十、計算配筋10.1 計算asxasx_1=o*mi_1/(0.9*(h-as)*fy) =1.0*25.83*106/(0.9*