Page 577 - 水土保持手冊_10612

B-B 斷面

∑ 84.99
= = = 2.07

∑ 41.07

= 0.685 O.K
∴ 偏心距 = 2.07 − 1.17 = 0.9 >

4
合力作用點超出四分點，故需以鋼筋補強，所需鋼筋量：

43.87
2
= = = 16.08

1.4 × 0.87 × 2.24

∵ d = 2.34 − 0.1�保護層� = 2.24
用 #8 鋼筋 @30cm = 17.00
2

C-C 斷面

混凝土的彎曲拉應力

6 6 × 16.88
2
2
f = = = 70.32 / = 7.03 /
1 × ℎ 2 1 × 1.2 2
0.03 = 4.2 /
′
2

(ACI 規範規定f < 0.03 )
′

故須用鋼筋加固，所需鋼筋量：

16.88
2
= = = 12.60 (保護層 0.1)

1.4 × 0.87 × 1.1

22.69
� = = = 0.169 = 16.9
140.0 × 0.87 × 1.1

(u = 0.1 = 14.0 / = 140 / )
′
2
2

用 #8 鋼筋 @30cm = 17.00
2

∑ = 23.33 > 16.9 O.K

工-3-19