STILLWATER, MN — 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, in a statement. "With better weather, we should be able to move more quickly to finish this iconic project." The St. Croix Crossing is a joint project between the Minnesota and Wisconsin Departments of Transportation to replace the 80-year-old Stillwater Lift Bridge with a new four-lane bridge to connect expressways on both sides of the St. Croix River. When the new St. Croix Crossing is complete, vehicle traffic will be re-routed onto the new bridge and the existing Stillwater Lift Bridge will be converted to a bicycle and pedestrian facility.

The Loop Trail, a 4.7-mile bicycle and pedestrian trail, will cross the St. Croix River at the Stillwater Lift Bridge and on the new St. Croix Crossing bridge. The Stillwater Lift Bridge will still need to accommodate boat navigation with lifts. May 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.

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.