West metro commuters will have to endure yet another major disruption this year, when sections of two busy roads in south Minneapolis — Portland and Cedar avenues — close this spring to allow Hennepin County to replace aging bridges across the Midtown Greenway.

The century-old bridges that carry Portland and Cedar over the former railroad corridor will be demolished in April, to be replaced later in the year by new bridges that resemble the originals.

The bridges “are in tough shape,” said Dean Michalko, Hennepin County’s project engineer. “It needs to get done.”

The bridge work comes on top of major construction along Interstate 94 from Minneapolis to Brooklyn Center that will choke traffic this summer. Between them, Portland and Cedar carry more than 24,000 vehicles a day.

Cedar, also known as County Road 152, draws about 13,500 vehicles a day, while Portland, or County Road 35, carries about 10,900 vehicles a day. Vehicle traffic will be rerouted starting in April, with pedestrians and bicyclists on the trail below detoured during temporary closures.

“We’re going to do our best to minimize the disruptions,” Michalko said.

Of the 38 bridges that cross the 2.8-mile historic corridor district, 26 remain that were built in nearly identical style from 1912 to 1916.

It will cost about $4 million to rebuild each bridge, about the same amount as rehabbing it, Michalko said. But a repaired bridge would last about 25 years, vs. the 75- to 100-year life span for the new bridges.

This year’s projects have spurred a broader discussion by county leaders about what to do with the other deteriorating bridges along the corridor, which is overseen by the Hennepin County Regional Railroad Authority.

There has been talk among rail authority commissioners, who also comprise the County Board, of permanently closing as many as half the historic bridges to save on the costs of repair or replacement.

Officials with the county, state Department of Transportation (MnDOT) and the state Historic Preservation Office will develop a plan to address the fate of the remaining bridges rather than take a piecemeal approach.

Historic character

The Midtown Greenway, built in the former railroad corridor, is a popular bike and pedestrian trail that stretches nearly 6 miles across south Minneapolis. Although the county’s railroad authority owns the former railroad corridor and its bridges, city and county streets cross it.

Officials still are deciding whether to rehab or replace a third bridge, the 103-year-old one on Fremont Avenue, which was shut down to car traffic last year because of safety concerns.

Major changes to most of the historic bridges must go through MnDOT and the state Historic Preservation Office. Those officials agreed that the Cedar and Portland bridges were beyond repair, but that replacing them would adversely affect the historic district. In the end, they recommended new bridges that fit the district’s historic character.

The Portland bridge was built in 1914-15 while the Cedar bridge was built in 1916-17, both with neoclassical revival style designs. The new bridges, slated to open by Thanksgiving, will mimic the old ones, although the vertical support piers will be aesthetic rather than functional and could be removed if transit is later approved for the corridor.

“We’re very pleased with the designs; they honor the historic nature of the bridges ... and yet obviously will be more modern,” said Soren Jensen, executive director of the Midtown Greenway Coalition. “I hope it creates a precedent for future design.”

Other improvements coming

If more bridges are torn down or replaced, officials agree, it could continue to affect the historic character of the Greenway.

A 2.8-mile stretch of the corridor, between Humboldt Avenue and 28th Street, was listed in the National Register of Historic Places in 2005. Since then, redevelopment in the area has exploded, with new apartments and ramps connecting the streets with the trail, changing the look and character of the trench in which the corridor sits. As a result, MnDOT is looking into re-evaluating or altering the corridor’s historic designation.

Other changes also are coming to the Greenway.

Hennepin County obtained a federal grant to improve seven crossings including Hiawatha Avenue, which is one of the most dangerous Greenway crossings.

A county grant also is funding a new pollinator garden along the corridor, while the state arts and cultural heritage fund is supporting two new murals there.