Concrete freeway dowels prompt questions


The in basket: The most common question to the Road Warrior column about something outside Kitsap County has to do with the rows of small rectangles that can be seen three abreast in the outside lane of I-90 between Cle Elum and Ellensburg and in places on I-5 as well. They go on for miles.

Don Bidwell and Bobby Whitlow are the latest to ask. 

Bobby says “I remember quite a few years ago when the crews were cutting them out on I-90 over Snoqualimie Pass and beyond. It looked like they were placing something in the holes before filling them back with concrete. I don’t know if they are sensors of some sort.”

Don said “They are always in the right lane where wear is heaviest and they did reduce the roughness and noise of the road bed for a time.  They have since also deteriorated. How could something that small and far apart create anything but more bumpiness?”

Dowels before being covered
Dowels before being covered Photo courtesy of Washington State Department of Transportation






The out basket: The rectangles show where dowels were put in across the seams between concrete panels of those highways, to keep the panels from rising or falling and creating the thump-thump of one’s tires at the seams when that happens.

A slot for the dowel is saw-cut out, then the 1 1/2-inch-by-18-inch dowel is laid and cemented into the slot and the cement ground down to pavement level. It is usually done in the outside lane where heavy trucks  take the heaviest toll on the road surface.

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