Figure 13 Cross-flooding through a series of structural ducts with 1 manhole
k
|
= |
0.2748
• Li
+ 0.0313 if 0 < L <
1i
|
k
|
= |
—0.0986
• Li
3 + 0.6873 • Li
2 – 1.0212 • Li
+
0.7386 if 1 ≤ Li
≤ 4
|
Note:
k is
the friction coefficient related to each space between two adjacent
girders. k is evaluated with effective cross-section
area therefore in calculations use the real cross-section area A and
not Sequiv. The pressure loss for entrance in the first
manhole is already computed in the calculation, and k = 1 has to be
added to take into account the outlet losses.
Figure 14 Cross-flooding through a series of structural ducts with 2 manholes
k
|
= |
0.4045
• Li
+ 0.0627 if 0 < L
< 1i
< 1
|
k
|
= |
0.0424
• Li
3 – 0.3593 • Li
2 + 1.1401 • Li
–
0.356 if 1 ≤ Li
≤ 4
|
Note:
k is
the friction coefficient related to each space between two adjacent
girders. k is evaluated with effective cross-section
area therefore in calculations use the real cross-section area A and
not Sequiv. The pressure loss for entrance in the first
manhole is already computed in the calculation, and k = 1 has to be
added to take into account the outlet losses.