= 2*[2.1*(700+183)+1.943*(800+158)]*0.992*1.43*790
= 8344926N ≥ Fl = 7662600N,满足要求。
(2)、角桩对承台的冲切验算:
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 = 1915650N
承台受角桩冲切的承载力按下列公式计算:
Nl ≤ [β1x * (c2 + a1y / 2) + β1y * (c1 + a1x / 2)] * βhp * ft * ho
(基础规范 8.5.17-5)
X 方向上自桩内边缘到最近柱边的水平距离:
a1x = 750 - 0.5hc - 0.5bp = 750-800/2-433/2 = 133mm
λ1x = a1x / ho = 133/(900-110) = 0.169
当 λ1x < 0.2 时,取 λ1x = 0.2,a1x = 0.2ho = 0.2*790 = 158mm
X 方向上角桩冲切系数 β1x = 0.56 / (λ1x + 0.2) (基础规范 8.5.17-6)
β1x = 0.56/(0.2+0.2) = 1.4
Y 方向上自桩内边缘到最近柱边的水平距离:
a1y = 750 - 0.5bc - 0.5bp = 750-700/2-433/2 = 183mm
λ1y = a1y / ho = 183/(900-110) = 0.232
Y 方向上角桩冲切系数 β1y = 0.56 / (λ1y + 0.2) (基础规范 8.5.17-7)
β1y = 0.56/(0.232+0.2) = 1.295
桩内边缘到承台外边缘的水平距离:
c1 = c2 = Sc + 0.5bp = 500+433/2 = 717mm
[β1x * (c2 + a1y / 2) + β1y * (c1 + a1x / 2)] * βhp * ft * ho
= [1.4*(717+183/2)+1.295*(717+158/2)]*0.992*1.43*790
= 2427090N ≥ Nl = 1915650N,满足要求。
3、承台斜截面受剪承载力计算:
(1)、X方向斜截面受剪承载力计算:
扣除承台及其上填土自重后 X 方向斜截面的最大剪力设计值:
Vx = Max{N1 + N2, N3 + N4} = 3831300N
承台斜截面受剪承载力按下列公式计算:
Vx ≤ βhs * βy * ft * bxo * ho (基础规范 8.5.18-1)
X 方向上自桩内边缘到最近柱边的水平距离:
ay = 750 - 0.5bc - 0.5bp = 750-700/2-433/2 = 183mm
λy = ay / ho = 183/(900-110) = 0.232
当 λy < 0.3 时,取 λy = 0.3
βy = 1.75 / (λy + 1.0) = 1.75/(0.3+1.0) = 1.346
βhs * βy * ft * bxo * ho = 1*1.346*1.43*2500*790 = 3709561N
< Vx = 3831300N,满足要求。
(2)、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: 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(80):http://www.youerw.com/gongcheng/lunwen_210.html