Download Cost Effective Drainage Structures

Cost Effective Drainage Structures
Henry J. “Hank” Gottschalk, III
Technical Resources Engineer
Virginia Concrete Conference
March 2010
Financial Assessment of Drainage Structure
 Cost of supply
Bridge Systems
Culverts
Pipes
Drainage Inlets
Our only limitation is our
customers’ imagination.
Horizontal Structures
 Conduit
 Structure
Purpose of vertical structure

Connect pipes
Purpose of vertical structure

Connect pipes

Provide access
Purpose of vertical structure

Connect pipes

Provide access
ASCE Photo Contest
Purpose of vertical structure

Connect pipes

Provide access
Shape
Round Vertical Structure
Round Vertical Structure
As = 0.0025 x D(in)
Round Vertical Structure
Rectangular Vertical Structure
Rectangular Vertical Structure
Rectangular Vertical Structure
Rectangular Vertical Structure
Financial Assessment of Drainage Structure
 Cost of supply
 Cost of proper installation & inspection
Highway Congestion

Congestion robs our nation of productivity and quality of life
– 3.5 billion hours/year time delay
– 5.7 billion gallons of wasted gas/year
– Total cost of $75 billion for the 75 urban areas
2010 FHWA Presentation - Reggie Holt, Sr. Bridge Engineer
Work Zone Safety
 Continued need for Accelerated Construction and methods to
close fewer lanes
TRB DCG Critical & Cross Cutting Issues, 01-14-11
Work Zone Safety
 As many as 1000 fatalities occur each year in roadway
construction work zones
TRB DCG Critical & Cross Cutting Issues, 01-14-11
Financial Assessment of Drainage Structure
 Cost of supply
 Cost of proper installation & inspection
Financial Assessment of Drainage Structure
 Cost of supply
 Cost of proper installation & inspection
 Maintenance
Financial Assessment of Drainage Structure
 Cost of supply
 Cost of proper installation & inspection
 Maintenance
 Service Life versus Project Life
U.S. Army Corps of Engineers
No. 1110-2-2902 Engineering and Design
Conduits, Culverts, and Pipes (31 March 1998)
Excerpt
from Para.
1-4
Life Cycle
Design
(1)
CONCRETE- Most studies estimated product service life for concrete pipe to be
between 70 and 100 years. Of nine state highway departments, three listed the life
as 100 years, five states stated between 70 and 100 years, and one state gave 50
years.
(2)
STEEL - Corrugated steel pipe usually fails due to corrosion of the invert or the
exterior of the pipe. Properly applied coatings can extend the product life to at least
50 years for most environments.
(3)
ALUMINUM- Aluminum pipe is usually affected more by soil-side corrosion than by
corrosion of the invert. Long-term performance is difficult to predict because of a
relatively short history of use, but the designer should not expect a product service
life of greater than 50 years.
(4)
PLASTIC- Many different materials fall under the general category of plastic. Each
of these materials may have some unique applications where it is suitable or
unsuitable. Performance history of plastic pipe is limited. A designer should not
expect a product service life of greater than 50 years.
Risk Assessment
Risk Assessment
 Modes of Failure
72”
Culvert Failure
Cost = Up to
$500,000
Major Highway
CLOSED
Business Profit
Decrease
Detour
Longer
Employee Commute
Public Driving
Confusion
Officials Manning
Roadblocks
The Economic Cost of Culvert Failure
User Delay Costs (Indirect Costs)
Joseph Perrin’s Research:
D = AADT * t * d *(cv * vv * vof + cf * vf)
Where:
AADT = Annual Average Daily Traffic of the roadway which the
culvert is being installed
t
= the average increase in delay or congestion the installation
is causing to each vehicle per day, in hours
d
= the number of days the project will take
cv
= the average rate of person-delay, in dollars per hour
vv
= the percentage of passenger vehicles traffic
vof
= the vehicle occupancy factor
cf
= the average rate of freight-delay, in dollars per hour
vf
= the percentage of truck traffic
User Delay Costs (Indirect Costs)
Average Established Delay Costs as of 2005, in Dollars:
cv = $18.62 per person / hour of delay
cf = $52.86 per freight /hour of delay
Typical Traffic Assumptions:
vv = 97% vehicle passenger traffic
vf = 3% truck traffic
vof =1.2 persons per vehicle
A one-hour delay on a roadway carrying an Annual Average Daily
Traffic of 20,000 vehicles costs the public over $450,000 every
day.
Risk Assessment
 Modes of Failure
Financial Assessment of Drainage Structure
 Cost of supply
 Cost of proper installation & inspection
 Maintenance
 Service Life versus Project Life
It is unwise to pay too much, but it is worse to pay too little.
When you pay too much, you lose a little money.
When you pay too little, you sometimes lose everything, because
the thing you bought was incapable of doing the thing it was
bought to do.
JOHN RUSKIN 1819-1900, renowned English critic, social commentator, and
economist of the Victorian Age
Advantages of
Precast Concrete Structures
Cast and Cured in a Quality Controlled
Environment
Shows up at the Jobsite as a Structure
Strength is All Ready “Built In”
Just Set, Connect… and Go!
Save Time & Money!
Precast Concrete = Long Service Life