Iowa State University engineers protect the bridges of Madison County

AMES, Iowa -- Iowa State University engineers are developing round-the-clock monitoring technology to help protect the bridges of Madison County.

That same technology could be adapted to any bridge where security is an issue, said Terry Wipf, the director of Iowa State's Bridge Engineering Center.

Madison County's historic covered bridges -- made famous by Robert James Waller's 1992 novel "The Bridges of Madison County" and the 1995 movie directed by Clint Eastwood -- have been arson targets in recent years. A September 2002 fire destroyed the 1883 Cedar Bridge. A year later the 1884 Hogback Bridge was damaged by an arson fire.

Engineers from the Bridge Engineering Center are now testing a monitoring system that will cover one of the bridges with three layers of remote monitoring equipment. Brent Phares, the associate director of the Bridge Engineering Center, said the equipment includes:

  • Flame detection devices. The devices detect infrared light, ultraviolet light and the flicker rate as the light frequencies change. Phares said flames emit a light signature the devices will recognize.
  • Infrared cameras. The cameras record heat rather than light. They'll photograph people at the bridge -- even on the darkest night. And they'll detect the heat flash if a fire is ignited.
  • Fiber-optic strain gauges. The gauges will be attached to the bridge and will measure changes in temperature.

Data from the monitoring equipment will be collected and processed by a computer at the bridge, Phares said. If the equipment detects something suspicious, emergency crews will be notified. Dispatchers will also have access to video images from the monitoring equipment so they can determine whether there's an emergency.

The equipment is expected to be installed on one of the covered bridges by September. Engineers and police officials will then stage mock arson and vandalism incidents to test the system's capabilities.

The project is supported by a $126,000 grant from the U.S. Department of Agriculture Forest Service's Forest Products Laboratory in Madison, Wis. The laboratory and the center have cooperated for more than 20 years on transportation research projects.

"I believe this will help more than anything we've done," said Todd Hagan, the Madison County engineer. "Our other forms of protection are all after-the-fact. This is hopefully something that will get us there before it's too late."