Nk = 3280; Mkx'= 0; Mky'= 0; Vkx = 0; Vky = 0
Fk = 3280; Mkx = 0; Mky = 0
F = 4428; Mx = 0; My = 0
三、承台自重和承台上土自重标准值 Gk:
a = 2(Sc + Sa) = 2*(0.5+0.75) = 2.5m
b = 2Sc + Sb = 2*0.5+1.32 = 2.32m
承台底部面积 Ab = a * b - 2Sa * Sb / 2 = 2.5*2.32-2*0.75*1.32/2 = 4.81m
承台体积 Vct = Ab * H1 = 4.81*0.9 = 4.329m
承台自重标准值 Gk'' = γc * Vct = 26*4.329 = 112.6kN
土自重标准值 Gk' = γs * (Ab - bc * hc) * ds = 20*(4.81-0.7*0.8)*1 = 85.0kN
承台自重及其上土自重标准值 Gk = Gk'' + Gk' = 112.6+85 = 197.6kN
四、承台验算:
圆桩换算桩截面边宽 bp = 0.866d = 0.866*500 = 433mm
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 = (3280+197.6)/3 = 1159.2kN ≤ Ra = 1500kN
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 = 197.6/3 = 65.9kN
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*(1159.2-65.9) = 1476.0kN
(2)、承台形心到承台两腰的距离范围内板带的弯矩设计值:
S = (Sa ^ 2 + Sb ^ 2) ^ 0.5 = (0.75^2+1.32^2)^0.5 = 1.518m
αs = 2Sa = 2*0.75 = 1.500m
α = αs / S = 1.5/1.518 = 0.988
承台形心到承台两腰的距离 B1:
B1 = Sa / S * 2Sb / 3 + Sc * (Sa + Sb) / S = 1.116m
M1 = Nmax * [S - 0.75 * c1 / (4 - α ^ 2) ^ 0.5] / 3 (基础规范 8.5.16-4)
= 1476*[1.518-0.75*0.7/(4-0.988^2)^0.5]/3
= 598.4kN•m
②号筋 Asy = 2232mm ζ = 0.065 ρ = 0.26%
1216@100 (As = 2413)
(3)、承台形心到承台底边的距离范围内板带的弯矩设计值:
承台形心到承台底边的距离 B2 = Sb / 3 + Sc = 0.940m
M2 = Nmax * [αs - 0.75 * c2 / (4 - α ^ 2) ^ 0.5] / 3 (基础规范 8.5.16-5)
= 1476*[1.5-0.75*0.8/(4-0.988^2)^0.5]/3
= 568.2kN•m
①号筋 Asx = 2071mm ζ = 0.07 ρ = 0.28%
918@110 (As = 2290)
2、承台受冲切承载力验算:
(1)、柱对承台的冲切验算: 六层现浇钢筋混凝土框架结构员工培训中心建筑与结构设计(74):http://www.youerw.com/gongcheng/lunwen_210.html