浙江省电力设计院 主控通信室结构计算书
Mxk'、Myk'-- 相应于荷载效应标准组合时,作用于基础顶面的弯矩值(kN·m); Mxk、Myk --- 相应于荷载效应标准组合时,作用于基础底面的弯矩值(kN·m); Mxk = Mxk' - Vyk·H、 Myk = Myk' + Vxk·H
F、Mx、My -- 相应于荷载效应基本组合时,竖向力、弯矩设计值(kN、kN·m); F = γz·Fk、 Mx = γz·Mxk、 My = γz·Myk Nk = 1676; Mxk'= 0; Myk'= 0; Vxk = 0; Vyk = 0 Fk = 1676; Mxk = 0; Myk = 0 F = 2262.6; Mx = 0; My = 0
三、承台自重和承台上土自重标准值 Gk:
a = 2Sc + Sa = 2*600+1800 = 3000mm; b = 2Sb = 2*1200 = 2400mm 承台底部底面积 Ab = a·b = 3*2.4 = 7.2m 承台体积 Vc = Ab·H = 7.2*1 = 7.2m
承台自重标准值 Gk\= γc·Vc = 25*7.2 = 180.0kN
承台上的土重标准值 Gk' = γs·(Ab - bc·hc)·ds = 18*(7.2-0.4*0.4)*1 = 126.7kN 承台自重及其上土自重标准值 Gk = Gk\= 180+126.7 = 306.7kN
四、承台验算:
圆桩换算桩截面边宽 bp = 0.8d = 0.8*600 = 480mm
1、承台受弯计算:
(1)、单桩桩顶竖向力计算: 在轴心竖向力作用下
Qk = (Fk + Gk) / n (基础规范 8.5.3-1) Qk = (1676+306.7)/2 = 991.4kN ≤ Ra = 1265kN
每根单桩所分配的承台自重和承台上土自重标准值 Qgk: Qgk = Gk / n = 306.7/2 = 153.4kN
扣除承台和其上填土自重后的各桩桩顶相应于荷载效应基本组合时的竖向力设计值: Ni = γz·(Qik - Qgk)
N = 1.35*(991.4-153.4) = 1131.3kN
(2)、Y 轴方向柱边的弯矩设计值:(绕 Y 轴)
Myct = Nl·(Sa - hc) / 2 = 1131.3*(1.8-0.4)/2 = 791.9kN·m
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浙江省电力设计院 主控通信室结构计算书
①号筋 Asx = 2509mm
δ = 0.03 ρ = 0.12%
24
14@100 (As = 3695)
ρmin = 0.15% As,min = 3600mm
2、承台受冲切承载力计算:
(1)、柱对承台的冲切计算:
扣除承台及其上填土自重,作用在冲切破坏锥体上的冲切力设计值: Fl = 2262600N
柱对承台的冲切,可按下列公式计算:
Fl ≤ 2[β0x·(bc + a0y) + β0y·(hc + a0x)]·βhp·ft·h0
(基础规范 8.5.17-1) X 方向上自柱边到最近桩边的水平距离:
a0x = 900 - 0.5hc - 0.5bp = 900-400/2-480/2 = 460mm λ0x = a0x / h0 = 460/(1000-110) = 0.517
X 方向上冲切系数 β0x = 0.84 / (λ0x + 0.2) (基础规范 8.5.17-3) β0x = 0.84/(0.517+0.2) = 1.172
a0y = Min{Sb - 0.5bc, H0} = Min{1000,890} = 890mm
2β0x·(bc + a0y)·βhp·ft·h0
= 2*1.172*(400+890)*0.983*1.433*890 = 3791161N ≥ Fl = 2262600N,满足要求。
(2)、角桩对承台的冲切计算:
扣除承台和其上填土自重后的角桩桩顶相应于荷载效应基本组合时的竖向力设计值: Nl = Nmax = 1131300N
承台受角桩冲切的承载力可由基础规范 8.5.17-1 式推导出按下列公式: Nl ≤ β1x·(bp + a1y)·βhp·ft·h0
X 方向上自桩内边缘到最近柱边的水平距离:
a1x = 900 - 0.5hc - 0.5bp = 900-400/2-480/2 = 460mm λ1x = a1x / h0 = 460/(1000-110) = 0.517
X 方向上冲切系数 β1x = 0.84 / (λ1x + 0.2) (基础规范 8.5.17-3) β1x = 0.84/(0.517+0.2) = 1.172
a1y = Min{Sb - 0.5bp, h0} = Min{960,890} = 890mm
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浙江省电力设计院 主控通信室结构计算书
β1x·(bp + a1y)·βhp·ft·h0
= 1.172*(480+890)*0.983*1.433*890 = 2013136N ≥ 1.1Nl = 1244430N,满足要求。
3、承台斜截面受剪承载力计算:
(1)、Y方向斜截面受剪承载力计算:
扣除承台及其上填土自重后 Y 方向斜截面的最大剪力设计值: Vy = Max{N1, N2} = 1131300N
承台斜截面受剪承载力按下列公式计算: Vy ≤ βhs·βx·ft·by0·h0 (基础规范 8.5.18-1)
Y 方向上自桩内边缘到最近柱边的水平距离:
ax = 900 - 0.5hc - 0.5bp = 900-400/2-480/2 = 460mm λx = ax / h0 = 460/(1000-110) = 0.517
βx = 1.75 / (λx + 1.0) = 1.75/(0.517+1.0) = 1.154
βhs·βx·ft·by0·h0 = 0.974*1.154*1.433*2400*890 = 3438220N ≥ Vy = 1131300N,满足要求。
4、柱下局部受压承载力计算: 局部荷载设计值 Fl = 2262600N
混凝土局部受压面积 Al = bc·hc = 160000mm
局部受压的计算底面积按下式计算: Ab = (bx + 2cx)(by + 2cy) cx = Min{Cx, bx, by} = Min{1300,400,400} = 400mm cy = Min{Cy, bx, by} = Min{1000,400,400} = 400mm Ab = (400+2*400)*(400+2*400) = 1440000mm
βl = (Ab / Al)0.5 = 1440000/160000)0.5 = 3
ω·βl·fcc·Al = 1.0*3*0.85*14.33*160000 = 5847223N ≥ Fl = 2262600N,满足要求。
5、桩局部受压承载力计算:
局部荷载设计值 F = Nmax + γg·Qgk = 1131.3+1.35*153.4 = 1338.3kN 混凝土局部受压面积 Al = π·d2 / 4 = 282743mm
局部受压的计算底面积按下式计算: Ab = π·(d + 2c)2 / 4 c = Min{Cx, Cy, d} = Min{300,900,600} = 300mm Ab = π*(600+2*300)2/4 = 1130973mm
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浙江省电力设计院 主控通信室结构计算书
βl = (Ab / Al)0.5 = 1130973/282743)0.5 = 2
ω·βl·fcc·Al = 1.0*2*0.85*14.33*282743 = 6888597N ≥ F = 1338336N,满足要求。
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