essays and articles by david g allen


State of West Virginia Faces a Hidden Highway Problem

 

My father was a registered professional civil engineer.  He built highways.  When I was learning the trade from him, I asked him for advice about a drainage culvert that was too small to handle the runoff from a storm.

His reply was logical and concise: "The pipe doesn't carry the water.  The hole does.  The pipe just keeps dirt from filling up the hole."

Since then, I have thought about pipes differently.

You probably don't think about roadway drainage, but for every mile of four-lane highway, there's a mile or so of drainage culverts.  Some are as small as 6 inches in diameter -- they drain underground springs or weeps.  Some are as large as 10 feet in diameter -- they allow streams and creeks to flow under highway fills.

The grassy median between divided highway lanes may look scenic to you as you drive.  But the median, with its buried culverts, exists mainly to drain surface water away from the roadway.

When I was a boy, almost all highway drainage culverts were made of reinforced concrete.  I grew up two miles from a concrete pipe plant.  That company's salesman was Earl Brane, a man who once worked for my grandfather as a highway superintendent. I assumed at the time that concrete pipe, and Earl Brane, would be around forever.  But I was disappointed on both counts.

Concrete pipe has a life expectancy of 80 to 100 years.  But it is bulky, requires heavy lifting equipment to install it and it comes in short joints.  The cost of installing concrete pipe eventually led to it being replaced with steel culverts.  Steel is lighter and comes in more manageable sections.

But the tradeoff for steel was not based on comparing apples to apples.  Corrugated steel pipe has a predicted life of 50 years or less -- half that of concrete.

Steel begins to oxidize the moment it is buried.  The industry has used several types of coatings to minimize oxidation, but the laws of physics are what they are.  When you bury steel, you essentially build a battery.

Older steel drainage pipes were most often coated with asphalt.  Epoxy and plastic coatings also are used for certain applications.  Steel pipe also is galvanized or aluminized to slow the oxidation rate.  These various coatings push the life expectancy out to 50 years.

Steel also is attacked by other elements, rainwater being the most corrosive.  Rainfall in West Virginia is acidic on the order of tomato juice.

As water runs off the roadway, it picks up particles of sand and grit that scour culverts over time.  Salt may melt snow and ice in the winter, but the salty meltwater also corrodes steel pipe.

The effects of the elements are insidious.  And like termite damage, the corrosion goes unnoticed until the culvert fails.  The invert, or bottom of the culvert, rusts away first, and then the culvert collapses for lack of structural strength.

The hole that carried the water starts filling up with dirt and debris.

West Virginia's modern highways are approaching the ripe age of 50.  I-81 in the Eastern Panhandle, I-70 in the Northern Panhandle and I-64 between Huntington and Charleston are perhaps the oldest Interstate highway sections.  Then come I-77 and I-79 north of Charleston. 

The newest Interstate sections, the Turnpike and I-64 from Beckley east, are about 20 years old.  Much of the Appalachian system (U.S. 50, I-68, U.S. 460) is more than 30 years old.

In the not too distant future, the then-governor will be looking at a very expensive repair bill for culvert replacement.  And that governor's successors will find themselves facing the same problem.

When a bridge collapses, any governor worth his salt has one thing on his mind -- camera time.  When the replacement bridge is built, that same governor will show up at the opening with ribbons and scissors.  Let's face facts -- bridges make for glamorous photo-ops.

Future governors who cut ribbons at the dedication ceremonies for new culverts obviously will be challenged.  Past is prologue.  And highway engineers will tell you that West Virginians have elected governors who became terribly confused when asked to identify a hole in the ground.

But I digress.

Fifty years ago, steel culverts were chosen to save construction money.  However, replacing these penny-wise pipes will cost a small fortune.  The task ahead will give a whole new meaning to the worn-out phrase "rebuilding the infrastructure."

 

David G. Allen of Clarksburg is a former assistant commissioner of the West Virginia Department of Highways.
 

 

"State of West Virginia Faces a Hidden Highway Problem" originally appeared in the October 19, 2007 issue of the West Virginia State Journal and was reprinted in the October 21, 2007 issue of the (Clarksburg) Sunday Exponent -Telegram.

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Copyright 1990-2007  David G. Allen