20 bridges closed on county roads in Lincoln
LINCOLN, Neb. (AP) — Twenty bridges in rural Lancaster County are closed, making life more difficult for several thousand people, based on the average daily count of vehicles that used those bridges.
More than 7,200 vehicles crossed the bridges each day before they were closed — ranging from 22 sets of wheels on a bridge on Princeton Road east of 134th Street, to more than 5,700 cars and trucks that used a bridge on North 148th Street that is now being replaced.
Most of the bridges, all closed within the past three years, had been damaged by heavy rains that cause dangerous erosion, according to Pam Dingman, county engineer.
The Lincoln Journal Star reports that the engineer recently closed four bridges after storms dumped about 7 inches of rain in parts of Lancaster County in late June.
Several of the problem bridges were built in the 1950s and early 1960s, using timber for some parts. That was a popular bridge construction method at the time, but there is a tendency for water to get behind the timber, which rots and creates maintenance problems, Dingman said.
Other closed bridges were built in the 1920s and 1930s, Works Progress Administration-era bridges, with washed-out footings no longer on solid ground.
“Their little feet aren’t in the dirt anymore,” Dingman says.
These older bridges generally cannot be repaired and need to be replaced. Their life expectancy was 50 years and they are nearing 100 years old.
The number of bridge closings is not unexpected, given their age and history. All were on a list of scour-critical and scour-susceptible bridges, meaning they already have serious problems. Forty-one bridges are currently on that list.
For example, one bridge (W171) on Pella Road near Southwest 14th Street, was built in 1961 with used bridge parts that were reassembled. The cost of $2,476.78 was a bargain, says Dingman.
The county made major repairs on the bridge in 2001, and in 2012, for another $36,661. “These were basically duct tape and bailing wire fixes to extend the life of the structure until the engineering department received funding to replace the bridge, Dingman said.
Now there are no other temporary fixes and closure is the only option, she said.
Bridges are closed only after a physical inspection and determination they are no longer safe, she said.
The county has seen more heavy rainstorms in recent years, always a problem with bridges. Intense rain in just a few hours leads to the erosion problems, she said.
The county engineer’s office is working to add specific rainfall data to a state bridge inventory, so staff can quickly determine what problem bridges might have experienced recent large rainstorms and need an inspection, she said.
Some of the low-traffic bridges may be closed for a long time because of funding problems.
The county has contracts to replace six of the closed bridges, and recently opened one, Dingman said.
Work is currently underway on the bridge with the most traffic, on 148th north of O Street, which has a 5,738 daily traffic count and is along a major route for commuters and school students heading to Waverly. The bridge is actually labeled a culvert, and had an 8-foot sink hole behind it, Dingman said.
The engineer at the time didn’t have the money to build a concrete floor on both the bridge and the box culverts at either end, said Dingman.
He had plans to come back and do the concrete work, but something else was always a higher priority.
Despite the hole, the county kept the bridge open this winter and spring, closely monitoring it until after the Fourth of July, at the request of Waverly leaders.
Dingman expects the bridge to open by Aug. 14 — if there are no rainy days.
Information from: Lincoln Journal Star, http://www.journalstar.com