W. River Parkway, Franklin Av. Bridge in Minneapolis to reopen

A barricaded portion of West River Parkway in Minneapolis will reopen for the first time in 26 months for the evening rush hour Thursday, just in time to offer some relief on what's expected to be a traffic-snarled evening.

The restoration of the busy route comes after the adjoining slope was rebuilt with the intent of preventing another mudslide like the one that sent more than 200 dump trucks' worth of rain-soaked debris onto the parkway in 2014. But there's been no assessment of whether nearby sections of bluff could fail.

The parkway is scheduled to reopen at 4:30 p.m. Thursday, hours before the Vikings, Gophers and Twins start games almost simultaneously. The opening also clears the traditional routes for the Minneapolis Bike Tour on Sept. 18 and the 10-mile race held with the Twin Cities Marathon on Oct. 9.

The parkway has been closed below the University of Minnesota Medical Center, which had several buildings at the edge of the precipice after the landslide. Retaining walls now buttress them.

The parkway could have reopened in July, but Hennepin County's reconstruction of the Franklin Avenue Bridge down river from the landslide required additional closures south to E. 24th Street.

The county said it aims to reopen the bridge to traffic by Thursday. But work is continuing, so bridge traffic may be hampered at times.

The parkway reopening is good news for people like Peter Vader, who says it's a less stressful route for commuting by bike to downtown from south Minneapolis. Robyn Anderson, who sometimes drives and bikes the route for its beauty, is eager for it reopen as well.

"I'm excited for it to reopen to have a better access to downtown and to the Grand Rounds," Anderson said.

The rebuilt 100-foot-wide section of bluff above the parkway now contains five retaining walls that supplement walls built by the Depression-era Works Progress Administration (WPA). New piping will route rain and snowmelt through a storm tunnel to the river, lessening the chance that soil will become saturated and slump onto the parkway.

But there's no guarantee there won't be landslides. Park official Cliff Swenson said other segments of the slope between the Franklin and Washington Avenue bridges have not been assessed for their potential to fail. Swenson is director of design and project management for the Minneapolis Park and Recreation Board, which owns the parkway and slope.

The repairs took far longer than expected. A project manager said the slope was so overgrown that park officials were unaware of one of the two WPA walls. Other complicating factors included the 45-degree angle of the slope and the way groundwater seeps laterally along the Platteville limestone, clay and other soils.

That combination of slope and dampness made it tricky to build a stable platform for necessary construction equipment. The earthen platform repeatedly slumped.

Two rows of steel piling, one straight down and the other angled into the bedrock, anchored the middle wall and were grouted in place. The middle wall provided the underpinning for smaller retaining walls that stair-step uphill from it. Two other retaining walls adjoin the parkway.

The project required "a lot of collaboration on a very challenging site," said Mike Haggerty, a senior geotechnical engineer for Barr, the project engineer.

The good news is that, according to the Park Board, the project budgeted at $6.3 million wound up costing $5.6 million. Federal disaster aid is expected to cover up to 75 percent of construction costs, and the state is expected to cover most of the rest. Fairview was budgeted to pay about $600,000.

The parkway handled about 6,900 motor vehicles and 1,000 cyclists a day before the landslide.

Steve Brandt • 612-673-4438

Twitter: @brandtmpls