HomeMy WebLinkAbout2017-10-19_Storm_rational_100Yr_17030(revised)STORM SEWER DESIGN (English Units)
This spreadsheet accomplishes a storm sewer design using the rational method. Enter the data in the non-shaded areas only.
Please use one spreadsheet per stormsewer run.
m =8.77 n =0.545 100 0.25 0.24
Location Discharge Drain Design Drain Profile
Drain Located On From Sta.To Sta.Source of
Drainage
Drainage
Area A
(acre)
Runoff
Coeff. C
CA (acre)Sum
CA
(acre)
Tc Across
Area
(minutes)
Total Tc = Col.
8a + Tc across
pipe length
(minutes)
Rainfall
Intensity
(in/hr)
Runoff (cfs)Contrib.
Inflow
(cfs)
Total Flow
(cfs)
Pipe Dia.
(in)
Manning
roughness
coefficient
"n"
Pipe
Slope
(ft/ft)
Velocity Of
Flow
(ft/s)
Pipe
Capacity
(cfs)
Pipe Velocity Check (Desirable
Minimum 3 ft/sec; Desirable
Maximum 10 ft/sec for Column 16)
Pipe Capacity Check (Column 13
vs. Column 17)
Pipe
Length***
(ft)
Elevation
Change (ft)
Upstr.
Invert Elev.
(ft)
Downstr.
Invert Elev.
(ft)
Upstr.
Ground
Elev. (ft)
Downstr.
Ground
Elev.
(ft)
1 2 3 4 5 6 7 8 8a 9 10 11 12 13 14 14a 15 16 17 17a 17b 18 19 20 21 22 23
Offsite North CB 12027 CB-1 Area 6 0.03 0.90 0.02 0.02 5.0 5.0 3.65 0.09 0.37 0.46 8 0.013 0.0100 3.46 1.21 VELOCITY OK ADEQUATE PIPE CAPACITY 70 0.70 337.90 337.20 343.48 340.04
See WSDOT Hydraulic Manual 6-5 for explanation of columns. http://www.wsdot.wa.gov/eesc/design/hydraulics/
Notes: Column 12 represents inflow from a storm sewer line, branch, an offsite source that flows into the trunk line being analyzed.
The conservative assumption is that the flow enters the storm sewer run at the upstream end of the run being analyzed.
For pipe cover calculation, Pipe cover = (Ground or Rim Elevation - Pipe invert elevation) - (pavement thickness) - (top of pipe thickness) - (pipe diameter).
The pipe thickness is based on the pipe diameter per WSDOT Manual Concrete for Shallow Pipe Cover Installations Fill Height Table 8-11.2
Please specify the largest pipe thickness of the storm sewer run being analyzed.
The spreadsheet will only calculate one storm sewer line at a time. Please copy the "Blank Template" and use this for calculating new storm sewer lines.
If analyzing complicated stormsewer system with multiple lateral lines to the trunk line, it is recommended that Stormshed be used to
model the conveyance system. Please contact your region Hydraulic Contact.
WARNING: START YOUR STORMSEWER RUN ON ROW 12. DO NOT SKIP ANY ROWS IN BETWEEN. USE ONE SHEET PER STORMSEWER RUN
Please report any problems to the WSDOT HQ Hydraulics Office.
Design Storm Event =
Project Name:Vantage Glen Stormline Extension Designed By:
Project Office:
Pipe Thickness (inches) =Pavement thickness (ft) =
11/21/2017 3:25 PM 1 of 2 2017-10-19_Storm_rational_100Yr_17030(revised).xls Offsite North
Jason Hein
Innova Architects
Remarks
Upstr. Pipe Cover (ft)Downstr. Pipe Cover (ft)Upstr. Pipe Cover Check (ft)Downstr. Pipe Cover Check (ft)
24 25 26 27 24
4.64 1.90 More than 2 ft of cover Low Cover - See Notes at Bottom
Designed By:
Project Office:
11/21/2017 3:25 PM 2 of 2 2017-10-19_Storm_rational_100Yr_17030(revised).xls Offsite North