Without funding, troubled waters ahead for Dakota County timber bridges
Rotting a concern
The timber supports to the bridge on County State Aid Highway 85 in Hampton Township have been replaced by Dakota County so the bridge can remain open until the timber bridge is replaced with a box culvert later this summer. This is the only timber bridge planned to be replaced this year at an estimated cost of $300,000. Photo submitted
Dakota County’s timber bridges are slowly rotting from the inside out and need replacement, but funding for the work is drying up.
The problem is apparent in Dakota County’s southern townships, where all timber bridges need to be replaced within the next decade, said Todd Howard, assistant county engineer, to Dakota County commissioners at a Tuesday committee meeting.
He called the condition of Dakota County’s timber bridges a concern, and said bond funds have been directed to state projects, including the Lowry bridge.
Howard said nine timber bridges in the county require a load restriction posting, an indication of the bridge’s strength and structural soundness, according to the Minnesota Department of Transportation.
The bridge on County State Aid Highway 46 in Marshan Township is classified as functionally obsolete, because its narrow lanes do not meet today’s minimum federal clearance requirements for a new bridge, Howard said.
The state of Minnesota’s timber bridges has raised the concerns of the Metropolitan Inter-County Association, which has made requesting bridge bonding part of its 2012 legislative platform.
According to MICA, local governments oversee 75 percent of the state’s 14,700 bridges.
It stated that counties with growing populations, like Dakota, have bridges that may be structurally sound, but are no longer capable of handling increased traffic.
Most of the state’s 1,631 timber bridges were built between 1940 and the 1970s, and 66 are in the metropolitan area.
Timber bridges are difficult to inspect, because internal rotting is not always apparent from an outside inspection, Howard said.
In 2010, a section of timber bridge in Nobles County near Brewster collapsed during an overlay project.
MICA is calling on the Legislature to allow those bridges to be eligible for funding through the state’s bridge bonding program.
Howard encouraged commissioners to discuss the concern with legislators as well.
“We absolutely need bonding to continue,” he said. “The township bridge account will in no way keep up with the needs of replacing those township bridges.”
Laura Adelmann is at laura.adelmann@ecm-inc.com or facebook.com/sunthisweek.
