Cost Effective Drainage Structures Henry J. “Hank” Gottschalk, III Technical Resources Engineer...

Cost Effective Drainage Structures

Henry J. “Hank” Gottschalk, IIITechnical 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.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 EngineersNo. 1110-2-2902 Engineering and DesignConduits, Culverts, and Pipes (31 March 1998)

(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.

Excerpt from Para. 1-4Life Cycle Design

Risk Assessment

Risk Assessment

Modes of Failure

72” Culvert Failure

Cost = Up to$500,000

Major Highway CLOSED

Business ProfitDecrease

Detour

Longer Employee Commute

Public DrivingConfusion

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 takecv = 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 hourvf = 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 ofPrecast 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