Bridges of Howard County

HOWARD COUNTY - A few weeks ago, the bridge collapse in Pittsburgh, Pa. on Jan. 28 was big news. Luckily there were no deaths and only four vehicles and a bus on the bridge at the time.

A much bigger and closer to Howard County bridge collapse happened on Aug. 1, 2007 in Minneapolis during the evening rush hour. Thirteen people were killed and 145 injured.

Even closer to home was the bridge on Cattle Creek Road near Bluffton in Winneshiek County. On May 5, 2017 an overloaded feed truck attempted to cross the bridge and it fell in.

In Howard County, the most recent bridge collapse was in spring 2000, when AF-39, west of Elma on 180th St., west of Bell Ave. It fell when a tractor pulling a folded disc hooked the bridge, causing it to collapse.

 

How many bridges does Howard County have?

Howard County Engineer Nick Rissman said, “We have over 2,000 structures in Howard County, ranging from 18-inch CMP’s (Corrugated Metal Pipe) to a 297 ft. bridge at Lidtke Mill near Lime Springs.”

Over 2,000 structures sounds like a lot, but in reality, to be labeled a bridge, the FHWA (Federal Highway Administration)  requires it has to be longer than 20 feet. Howard County has 209 that fit that criteria. That is also how many bridges Howard County is responsible to inspect.

Rissman explained, “This includes six city bridges and four bridges that are closed to traffic. It does not include bridges on our county lines that are inspected by our neighboring counties.”

 

How safe are Howard County bridges?

Fifty of the 209 bridges are considered poor, which includes the four which are closed to traffic. That is 23.9% or 22.4%, if you don't consider the closed bridges. Nineteen of those bridges do not have a load posting. In addition, some bridges that are not considered poor have a load posting. Rissman noted, “This is mostly due to the 2018 Legislation that allows heavy loads for special haul vehicles.”

Forty-one open-to-traffic bridges have structural elements older than 60 years. There are also two open-to-traffic bridges that have components older than 100 years.

~ C-9 (Jones Bridge between Chester and Lime Springs is on 25th Street, east of Highway 63) has a pier that was built in 1880.

~ H-7 (on Howard Ave., about two miles south of Highway 9) was built in 1920.

“In the 2010s, we replaced or did significant structural rehabilitation to 43 bridges,” Rissman said. “This is the most in any one decade since the 1950s.  

“We have replaced 11 so far in the 2020 decade.  For comparison, we replaced 24 in the 2000s, 25 in the 1990s, 34 in the 1980s, 24 in the 1970s, 14 in the 1960s and 63 in the 1950s.” The bridges mentioned are all greater than 20 feet or were greater than 20 feet prior to replacement.  

“Of the 54 bridges we have replaced since 2010, 30 of them have been partially or fully paid for with Windmill TIF money. TIF has been a godsend to our department.”

Howard County Auditor Julie Chapman explained that with the Windmill TIFs, the County creates an Urban Renewal Plan with the proposed projects. Then the board can borrow a General Obligation Capital loan to fund the proposed projects.

When the three wind farms pay their taxes, the board captures their taxes, minus any debt levies, to pay back the GO bond.

 

 What is a ‘poor’ bridge?

A bridge that is considered “Poor” is a bridge in which significant load-carrying elements are found to be in poor condition due to deterioration or a bridge in which the adequacy of the waterway opening provided by the bridge is determined to be extremely insufficient to the point of causing intolerable traffic interruptions.  

This does not mean a poor bridge is unsafe.  It just means that, most typically a specific load-carrying element of the bridge has been rated four or less on a 0-9 scale.  Zero indicates failure and nine is excellent.

Rissman stated, “If we were concerned about the safety of the bridges, we’d close them. Through history, Howard County has closed 20 bridges.  Three of those 20 have since been replaced.  

 

Bridge structures

Rissman noted the bridge that collapsed in Pittsburgh was a steel K-frame. The ones in Winneshiek and Howard Counties were both truss bridges.

The thing in common with the failures is they did not have redundancy. Each only had two load path elements holding the bridge up.  Bridges with redundancy have three or more load path elements and are much less likely to collapse, thus safer.    

The most recent bridge closed was Gansen Bridge between Lime Springs and Chester in August 2020. It was the last bridge open-to-traffic that did not have redundancy.

 

Upcoming projects

Secondary Roads plans to use TIF money to re-pave parts of V26 and A23.

“We also want to replace two bigger, $1.5 million bridges,” Rissman said. “Our previous TIFs focused on smaller bridges.”

Rissman is hoping to replace the Florenceville Bridge (AL-3) with state bridge funds. Then he can do two more bridges with TIF:

• AF-42, west of Elma on the pavement is planned to be replaced from TIF funds.

• C-9, Jones Bridge, between Chester and Lime Springs, is planned to be replaced if the Florenceville Bridge gets state funding.

“Without TIF,” Rissman acknowledged, “A significant number of the replaced bridges would have been closed.”