相应于荷载效应及标准组合及竖向力Word文档格式.docx
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H=1.35Hk=125.955KN
对于承台进一步设计为:
取承台厚0.9m,下设厚度为100mm,强度等级为C10的混凝土垫层,保护层为50mm,则h=0.85m;
混凝土强度等级为C20,混凝土的抗拉强度为ft=1.1N/mm2,钢筋选用HRB335级,fy=300N/mm2
则各桩不计承台以及其上土自重Gk部分的净反力Ni为
各桩平均竖向力N=1.35Fk/n=562.18KN
最大竖向力Nmax=1.35(Fk/n+Myxmax/Ʃxj)
=1.35*(416.4+116.6)
=719.55
对于Ⅰ-Ⅰ断面
My=ƩNixi=2Nmaxxi=2*719.55*1.1=1583.01
钢筋面积As=My/0.9fyh0=1583.01*106/(0.9*300*850)=6897.65mm2
采用22根直径为20mm钢筋,As=6908mm2平行于X轴布置
对于Ⅱ-Ⅱ断面
Mx=ƩNiyi=2Nxyi=2*562.18*0.4=449.74
钢筋面积As=Mx/0.9fyh0=449.74*106/(0.9*300*850)=1959.6mm2
选用18根直径为12mm的钢筋,As=2034.72mm2平行于Y轴布置
6.承台抗冲切验算
1柱的向下冲切验算
Fl<
=2[β0x(bc+a0y)+β0y(ac+a0x)]βhpfth0
式中;
a0x=0.9mλ0x=a0x/h0=0.9/0.85=1.059
β0x=0.84/(λ0x+0.2)=0.67
a0y=0.2mλ0y=a0y/h0=0.2/0.85=0.235
β0y=0.84/(λ0y+0.2)=1.93
bc=0.6mac=0.6mβhp=1-(1-0.9)/(2000-800)*(900-800)=0.992
则2[β0x(bc+a0y)+β0y(ac+a0x)]βhpfth0
=2*[0.67*(0.6+0.2)+1.93*(0.6+0.9)]*0.992*1100*0.85
=6364.64KN
桩顶平均净反力N=2248.74/4=562.19KN
Fl=F-N=2248.74-562.19=1686.55
2角桩的冲切验算
冲切力Nl必须不大于抗冲切力即满足
Nl<
=[β1x(c2+aiy/2)+β1y(c1+a1x/2)]βhpfth0
式中c1=c2=0.6m
a1x=0.9mλ1x=a1x/h0=1.059β1x=0.56/(x1x+0.2)=0.448
a1y=0.2mλ1y=a1y/h0=0.235β1y=0.56/(x1y+0.2)=1.29
Nl=Nmax=719.55KN
抗冲击力=[0.4448*(0.6+0.2/2)+1.29*(0.6+0.9/2)]*0.992*1100*0.85
=1545.12KN
7.承台抗剪验算
剪切力V必须不大于抗剪切力,即满足
V<
=βhsβftbh0
对于Ⅰ-Ⅰ截面
ax=0.9λx=ax/h0=0.9/0.85=1.059β=1.75/(λx+1)=0.85
βhs=(800/h0)1/4=0.985b=2.2m
V=2*Nmax=2*719.55=1439.1
抗剪切力=0.985*0.85*1100*2.2*0.85=1722.22
对于Ⅱ-Ⅱ截面
a1y=0.2mλy=0.235β=1.75/(0.235+1)=1.417
a=3.6m
V=2*N=2*562.18=1124.36KN
抗剪力=0.985*1.417*1100*3.6*0.85=4698.1KN
8.沉降计算
采用实体深基基础计算方法,计算中心点沉降。
荷载扩散法计算
P0=(F+Gk-Pc0xaxb)/[(b0+2l*tanФ/4)*(a0+2l*tanФ/4)]
式中F为相应于荷载效应准永久组合时分配到桩顶的竖向力
F=1428.93Gk=316.8KNPc0=16*2=32KN/m2
l=10ma0=3.2mb0=1.8ma=3.6mb=2.2m
则P0=(1428.93+316.8-32*3.6*2.2)/[(3.2+2*10tan6o)*(1.8+2*10tan6o)]=1492.3/(5.3*3.9)=72.2KPa
s=∮ps'
s'=ƩP0/Esi(ziαi-zi-1αi-1)
对于扩散后实体基础查表确定平均附加应力系数α
a/b=5.3/3.9=1.4
z/m
z/b0
αi
ES
1.0
20
1.95
0.5
0.9215
3.1
0.8
0.810
3.9
0.749
7.8
2.0
0.499
8
11.7
3.0
0.366
12.48
3.2
0.348
13.26
3.4
0.331
Ʃsi'=72.2*{[(1.95*0.9215)+(3.1*0.810-1.95*0.9215)+(3.9*0.749-3.1*0.810)]*1/20+[(7.8*0.499-3.9*0.749)+(11.7*0.366-7.8*0.499)+(12.48*0.348-11.7*0.366)]*1/8}
=72.2*{(3.9*0.749)*1/20+[(12.48*0.348)-(3.9*0.749)]*1/8}
=23.4
△sn=(13.26*0.331-12.48*0.348)*72.2/8
=0.282mm<
0.025Ʃsi=0.54mm
计算到桩端以下8.7m即可。
ES=ƩAi/Ʃ(Ai/Bsi)=(1.79+0.71+0.41+0.97+0.39)/(0.1455+0.17)
=13.53MPa<
15MPa
∮p=0.5
s=∮ps‘=21.6*0.5=10.8mm
A*5
相应于荷载效应的标准组合的竖向力Fk=7070.5KN,MK=527.9KN·
m,Hk=105.6KN
先假设承台尺寸为4m*4m,厚为1.0m,承台及其上土平均容重为20KN/m3,则承台及其上土自重的标准值为:
Gk=20*4*4*2=640KN
=(Fk+Gk)/n=(7070.5+640)/543.34=14.2
可取15根桩,承台的面积尺寸为3.6m*6.4m
按照设计的承台尺寸,计算Gk=3.6*6.4*2*20=921.6KN
Qk=(Fk+Gk)/n=(7070.5+921.6)/15=532.8KN
Qk=532.8KN<
=532.8+(527.9+105.6*2)*1.4/(4*1.42)
=627.61
Qkmax=627.61KN<
F=1.35Fk=9545.18KN
M=1.35Mk=712.7KN·
H=1.35Hk=142.56KN
各桩平均竖向力N=1.35Fk/n=636.35KN
=1.35*(471.4+131.98)
=814.6
My=ƩNixi=2Nmaxxi=2*814.6*1.1=1792.12
钢筋面积As=My/0.9fyh0=1792.12*106/(0.9*300*850)=7808.8mm2
采用25根直径为20mm钢筋,As=7850mm2平行于X轴布置
Mx=ƩNiyi=2Nxyi=2*636.35*0.4=509.08
钢筋面积
As=Mx/0.9fyh0=509.08*106/(0.9*300*850)=2218.21mm2
选用20根直径为12mm的钢筋,As=2260.8mm2平行于Y轴布置
a0x=1.1mλ0x=a0x/h0=1.1/0.85=1.294
β0x=0.84/(λ0x+0.2)=0.56
a0y=0.9mλ0y=a0y/h0=0.9/0.85=1.059
β0y=0.84/(λ0y+0.2)=0.67
bc=0.6mac=3mβhp=1-(1-0.9)/(2000-800)*(900-800)=0.992
=2*[0.56*(0.6+0.9)+0.67*(3+1.1)]*0.992*1100*0.85
=6654.03KN
桩顶平均净反力N=9545.18/15=636.35KN
Fl=F-N=9545.18-636.35=8908.83
a1x=1.1mλ1x=a1x/h0=1.294β1x=0.56/(x1x+0.2)=0.375
a1y=0.9mλ1y=a1y/h0=1.059β1y=0.56/(x1y+0.2)=0.4448
Nl=Nmax=814.6KN
抗冲击力=[0.375*(0.6+0.9/2)+0.4448*(0.6+1.1/2)]*0.992*1100*0.85
=839.7KN
ax=1.1λx=ax/h0=1.1/0.85=1.294β=1.75/(λx+1)=0.76
βhs=(800/h0)1/4=0.985b=3.6m
V=2*Nmax=2*814.6=1629.2
抗剪切力=0.985*0.76*1100*3.6*0.85=2519.79
a1y=0.9mλy=1.059β=1.75/(0.235+1)=0.85
a=6.4m
V=2*N=2*636.35=1272.7KN
抗剪力=0.985*0.85*1100*6.4*0.85=5010.1KN
F=5907.7Gk=921.6KNPc0=16*2=32KN/m2
l=10ma0=6mb0=3.2ma=6.4mb=3.6m
则P0=(5907.7+921.6-32*6.4*3.6)/[(6+2*10tan6o)*(3.2+2*10tan6o)]=6092.02/(8.1*5.3)=141.9KPa
a/b=8.1/5.3=1.6
2.65
0.927
0.6
0.898
5.3
0.764
10.6
0.518
15.9
0.383
16.96
0.364
18.02
0.346
Ʃsi'=141.9*{[(2.65*0.927)+(3.1*0.898-2.65*0.927)+(5.3*0.764-3.1*0.898)]*1/20+[(10.6*0.518-5.3*0.764)+(15.9*0.383-10.6*0.518)+(16.96*0.364-15.9*0.383)]*1/8}
=141.9*{(5.3*0.764)*1/20+[(16.96*0.364)-(5.3*0.764)]*1/8}
=66.4
△sn=(18.02*0.346-16.96*0.364)*141.9/8
=1.09mm<
0.025Ʃsi=1.66mm
ES=ƩAi/Ʃ(Ai/Bsi)=(2.46+0.33+1.27+1.44+0.59)/(0.203+0.25)
=13.44MPa<
s=∮ps‘=66.4*0.5=33.2mm
1×
C
相应于荷载效应的标准组合的竖向力Fk=1881.255KN,MK=451KN·
m,Hk=90.3KN
采用截面直径为400的预制钢筋混凝土圆桩,桩端进入持力层为1.5m,桩长8.4m,承台埋深为1.7m。
Ra=
=637KN
Gk=20×
2×
1.7=136KN
=
=3.16
可取4根桩,承台的面积尺寸为2.2m×
3.6m
按照设计的承台尺寸,计算Gk=2.2×
3.6×
20=269.28KN
Qk=
=537.63KN
Qk=537.63KN<
Ra=637KN
Qkmax=
+
=537.63+
=537.63+84.93=622.56
Qkmax=622.56KN<
1.2Ra=764.4KN
F=1.35Fk=2540.7KN
M=1.35Mk=609KN·
H=1.35Hk=121.5KN
各桩平均竖向力N=1.35
=634.83KN
最大竖向力Nmax=1.35(
)
=1.35×
(470+84.93)
=749.15
My=ƩNixi=2Nmaxxi=2×
874.46×
1.1=1749.96KN.m
钢筋面积As=
=7834mm2
采用21根直径为22mm钢筋,As=7982mm2平行于X轴布置
Mx=ƩNiyi=2Nxyi=2×
634.83×
0.4=509.6kn.m
=2220.4mm2
选用16根直径为14mm的钢筋,As=2462.4mm2平行于Y轴布置
a0x=0.9mλ0x=
=1.059
β0x=
)=0.67
a0y=0.2mλ0y=
=0.2/0.85=0.235
β0y=1.93
bc=0.6mac=0.6mβhp=
=0.992
=2[0.67(0.6+0.2)+1.93(0.6+0.9)]×
0.992×
1100×
0,85
桩顶平均净反力N=
=635.17KN
Fl=F-N=2540.7-635.17=1905.52kn
a1x=0.9mλ1x=
=1.059β1x=
=0.448
a1y=0.2mλ1y=
=0.235β1y=
)=1.29
Nl=Nmax=749.15
抗冲击力=[0.4448×
(0.6+
)+1.29×
)]×
0.85
ax=0.9λx=
=1.059β=
=0.85
βhs=
=0.985b=2.2m
V=2×
Nmax=2×
634.83=1269.66kn
抗剪切力=0.985×
0.85×
2.2×
0.85=2000.25kn
a1y=0.2mλy=0.235β=
=1.417
N=2×
634.83=1269.66KN
抗剪力=0.985×
1.417×
0.85=4698.1KN
P0=(F+Gk-Pc0xaxb)/[(b0+2l×
tanФ/4)×
(a0+2l×
tanФ/4)]
F=1564.9KNGk=269.28KNPc0=16×
1.7KN/m2
l=8.4ma0=2.4mb0=1.35ma=3.6mb=2.2m
则
P0=
=85.78
a/b=
=1.4
1.85
0.86
0.780
3.7
7.4
11.1
11.84
12.58
Ʃsi'=85.78×
[1.85×
0.9215+﹙3.2×
0.780-1.85×
0.9215﹚+﹙3.7×
0.749-3.2×
0.780﹚]
+[﹙67.4×
0.499-3.7×
0.745﹚+﹙11.1×
0.366-7.4×
0.499﹚+﹙111.84×
0.348-11.1×
0.366﹚]
=27.4mm
△sn=(12.58×
0.331-11.84×
0.348)
=0.5211<0.025
SI=0.685
ES=ƩAi/Ʃ(Ai/Bsi)=
=13.71MPa<
∮p=0.5
S=
=27.4×
0.5=13,.7
C*1
相应于荷载效应的标准组合的竖向力Fk=1908.09KN,MK=427.41KN·
m,Hk=85.5KN
=(Fk+Gk)/n=(1908.09+160)/543.34=3.8
可取5根桩,承台的面积尺寸为2.2m*3.6m
Qk=(Fk+Gk)/n=(19