November 29, 2007

Please Post Your Answer to Worked Example 2.3

Please Post Your Answer to Worked Example 2.3 here.

Filed under 1 by

Spread the Word!

Permalink Print Comment

Comments on Please Post Your Answer to Worked Example 2.3 »

November 29, 2007

choong @ 4:49 pm

Preliminary storage volume 16694m³
Minor design storm outlet 0.8×2.1 culvert Q=5.948m³ less than pre dev Q of 6.35m²

Major design storm outlet 0.5×4 culvert
Q=9.762m³ less than pre dev Q of 9.85m³
50 yr WL=102.25m

spill way 3m width at 102.55m

suhayati Abd Rahman @ 5:56 pm

minor design storm: Q5 30 min
Q5=5.732m3/s < 6.34m3/s ,WL=101.5m
Culvert size:2.5m x 0.9m add factor 2 time for the stage storage.
Major design storm:Q50 30 min
Q50=8.092m3/s < 9.85m3/s, WL=101.75m
Culvert size:6.0m x 0.8m
Emergency Spillway: Q100 50 min
Q100=12.861m3/s, spillway level=101.75+0.3=102.5
size :L=3m

suhayati Abd Rahman @ 6:25 pm

Group E:
minor design storm: Q5 30 min
Q5=5.732m3/s < 6.34m3/s ,WL=101.5m
Culvert size:2.5m x 0.9m add factor 2 time for the stage storage.
Major design storm:Q50 30 min
Q50=8.092m3/s < 9.85m3/s, WL=101.75m
Culvert size:6.0m x 0.8m
Emergency Spillway: Q100 50 min
Q100=10.339m3/s, spillway level=101.75+0.3=102.5
size :L=3m

alexyap @ 6:28 pm

group B

answer

5yr pre dev outflow limit = 9.20 m3/s
50yr pre dev outflow limit = 13.49 m3/s

Using culvert size 0.8m x 2.2m and routing 5yr 60min for minor design storm primary outlet gives max. discharge of 8.6m3/s at WL=101.75m, less than outflow limit = 9.20 m3/s

Using culvert size 0.75m x 3m for major design storm primary outlet and routing 50yr 60min gives max. discharge of 13.15 m3/s at WL=102.25m, less than outflow limit 50ARI = 13.49 m3/s

After routing 100ARI 60min, the secondary spillway outlet was required at WL=102.25m with a discharge of 14.9m3/s. Therefore it was placed at WL=102.55m (0.3m above 50ARI WL) at a width of 3m and freeboard of 0.3m

khusairy @ 6:33 pm

Group A

minor design storm: Q5 30 min
Q5=6.349m3/s < 6.39m3/s at WL=102.0m
Culvert size: 0.8m x 2.3m

Major design storm Q50 30min
Q50 = 9.844m3/s < 9.85m3/s at WL = 102.25m
Culvert size 2m x 1.5m

Spillway: Q100 30min
Q100 = 10.233m3/s at WL = 102.25 + 0.3 = 102.55m
size L = 3m

November 30, 2007

kee1688 @ 8:56 am

group D

5yr pre dev outflow limit = 6.35 m3/s
50yr pre dev outflow limit = 9.85 m3/s

minor design storm, Q5 30 min
proposed 0.75 x 2.5m box culvert
max discharge for 5 yrs routing is 6.35 m3/s
with water level 102.00m

major design storm, Q50 30 min
proposed 0.5m x 4m box culvert with invert level 102.00m
max discharge for 50 yrs routing is 8.17m3/s
with water level 102.25m

Emergency spillway, Q100 30 min
proposed 3m width broad crested weir with invert level 102.5m (allow 0.25m freeboard)
max diacharge for 100 routing is 9.89m3/s

Using culvert size 0.75m x 3m for major design storm primary outlet and routing 50yr 60min gives max. discharge of 13.15 m3/s at WL=102.25m, less than outflow limit 50ARI = 13.49 m3/s

After routing 100ARI 60min, the secondary spillway outlet was required at WL=102.25m with a discharge of 14.9m3/s. Therefore it was placed at WL=102.55m (0.3m above 50ARI WL) at a width of 3m and freeboard of 0.3m

kee1688 @ 9:02 am

group D

Please ignore the previous answer

5yr pre dev outflow limit = 6.35 m3/s
50yr pre dev outflow limit = 9.85 m3/s

minor design storm, Q5 30 min
proposed 0.75×2.5m box culvert
max discharge for 5 yrs routing is 6.35 m3/s
with water level 102.00m

major design storm, Q50 30 min
proposed 0.5m x 4m box culvert with invert level 102.00m
max discharge for 50 yrs routing is 8.17m3/s
with water level 102.25m

Emergency spillway, Q100 30 min
proposed 3m width broad crested weir with invert level 102.5m (allow 0.25m freeboard)
max diacharge for 100 routing is 9.89m3/s

suhayati Abd Rahman @ 10:01 am

Dr Quek,
i just realized that Group A & D are using more or less the same size of culvert as group E without increasing the storage. I wonder why….so i tried to apply it in my spreedsheet and found that their proposed size cant be applied on nomograph mean that no value or beyond the graph…..please comment.

LIEW TIAM MING @ 11:07 am

please ignore the previous answer

Group A

minor design storm: Q5 30 min
Q5=5.291m3/s < 6.39m3/s at WL=102.0m
Culvert size: 1.8m x 2.5m

Major design storm Q50 30min
Q50 = 9.424m3/s < 9.85m3/s at WL = 102.25m
Culvert size 2m x 2.5m

Spillway: Q100 30min
Q100 = 12.175m3/s at WL = 102.5 + 0.3 = 102.8m
size L = 3m

Leave a Comment