CTRE is an Iowa State University center, administered by the Institute for Transportation.

Address: 2711 S. Loop Drive, Suite 4700, Ames, IA 50010-8664

Phone: 515-294-8103
FAX: 515-294-0467

Website: www.ctre.iastate.edu/

Iowa State University--Becoming the Best

In-Service Evaluation of Culvert Extensions

Researcher(s)

Principal investigators:

Project status

In progress

Start date: 07/01/17
End date: 12/31/18

Sponsor(s)/partner(s)

Sponsor(s): Iowa Department of Transportation

About the research

Abstract:

Current design manuals direct designers to extend culverts to the edge of clear zone before connecting to the wing wall. However, in the case of large culverts, placing vertical drop-offs at the edge of clear zone is still concerning and may warrant protection. In these cases, since a barrier may already be warranted, there exists a potential cost savings by shortening the culvert and connecting to the wing wall just beyond the deflection of the barrier.

While introducing a barrier would replace one hazard with another, unprotected culverts/pipe openings account for an annual average societal cost of $33.5 million. Protecting these openings with barriers may be a cost savings by itself, but paired with the reduced construction cost by shortening the culvert, the combination may be even more beneficial.

The goals of this study are as follows: