Final construction season begins at St. Croix Crossing
Premier infrastructure project to open to traffic in late summer
STILLWATER, Minn. (May 30, 2017) – The final summer construction season on the St. Croix Crossing bridge project has begun and crews will perform a variety of finishing details throughout the summer to prepare for traffic later this year.
Construction crews have been working at the project site throughout the winter and early spring, but with warmer temperatures and more predictable weather, contractors are now able to schedule more work.
“We were able to fully connect all the bridge spans with closure pours during the winter months and began work on things like electrical and drainage systems,” said Terry Zoller, project engineer for the Minnesota Department of Transportation. “With better weather, we should be able to move more quickly to finish this iconic project.”
During May, crews began work to finish the driving and walking surfaces of the bridge and to chip seal the bridge deck. In this process, an epoxy resin is poured and evenly spread onto the driving surface of the bridge. Small, aggregate gravel is then broadcast on top of it. The gravel sticks to the epoxy, creating a water-tight, non-slip driving surface that is smooth and more durable. Two layers of the epoxy and aggregate will be completed to create a longer-lasting driving surface that will stand up better to Midwest weather extremes. Chip sealing will continue through early June, according to Zoller.
Professional painting crews also began the long process of painting the bridge with a tan color reflective of the bluffs on the east bank of the St. Croix River. The paint is formulated specifically for the bridge, to better withstand temperature and weather extremes without peeling or cracking. Workers will apply paint to the majority of the bridge structure by roller brush to avoid overspray issues and to directly apply a more even coat of paint on all surfaces. Crews will spray the approach bridges because they can more easily access the surfaces to paint. Zoller said the painting will likely require much of the summer months to complete, due to the bridge’s significant size and weather conditions that can change from day to day.
Road crews added curb, gutter and sidewalk systems and median barriers. On the Wisconsin side, crews completed backfilling behind the bridge abutment and will finish the approach ramp to the westbound side of the bridge in June.
During June, work will take place to complete installation of electrical systems within the bridge, including its lighting systems. Bridge planners chose to use lighting systems that illuminate the driving and walking surfaces of the bridge during nighttime hours but avoid giving off any significant ambient light. Lighting fixtures will also use energy-efficient LED technology to light surfaces.
Crews will also complete work on storm water drainage systems for the bridge, which will carry water from the bridge deck to holding ponds on either side of the bridge. Sediments from the storm water will be allowed to settle in the holding ponds before the water is placed back into the St. Croix River. In addition, mooring cells located near Xcel Energy’s King Plant, which held barges of construction materials, will continue to be removed throughout June. The St. Croix riverbed, where the cells were located, will be restored to its original condition.
“We wanted to build a bridge that all of Minnesota and Wisconsin would be proud of for generations to come,” said Zoller. “A bridge that safely carries traffic but also lives in harmony with the surrounding ecosystem and reduces environmental impacts wherever possible. Everyone involved with this project knows we are accomplishing these goals.”
Restoration work around the massive construction project, which is scheduled to begin in June, will continue through July and beyond. Although landscaping will continue in future weeks and months, construction equipment will be removed. On the bridge, crews will paint the lane markings on the eastbound and westbound sides. Installation of ornamental railings and light fixtures will be concluded and painting operations will likely wrap up as well.
Although no official opening date has been determined, Zoller expects most on-bridge work to be completed by August. During the months after the bridge opens to traffic, crews will need to landscape areas previously used for construction operations. Additional lighting or signage may also be required.
“We know that people are chomping at the bit to begin using this beautiful bridge,” said Zoller, “but we want to make sure everything is just right before the first car drives across.”
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