Final work on St. Croix Crossing this summer
For the past several years, thousands of experienced designers, engineers and highly skilled craftspeople have worked to build and deliver what many believe will become a once-in-a-generation piece of vital infrastructure for Minnesota and Wisconsin. It will not only serve a need to improve traffic flows between our fine states, but it will also etch an iconic profile along the St. Croix valley. Further, it is designed and built to withstand Upper Midwest weather and serve drivers, bikers and pedestrians for generations to come.
As the leaders for the St. Croix Crossing project, we wanted to take the final months of the project to provide you with perspectives you may not receive through traditional means. To begin, we wanted to explain what construction activities will take place during the final summer construction season at the project since most of you won’t be able to see the work from a nearby road, walking trail or from the water.
Throughout the winter and early spring, construction crews have been working at the project site. They fully connected all the bridge spans with closure pours, then began work on things like electrical and drainage systems. With warmer temperatures and more predictable weather, we should be able to move more quickly to finish this project. Here is a general timeline of activities before we open the bridge to traffic later this year:
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. This work should continue through early-June.
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 most of the bridge structure by roller brush. This may seem somewhat counterintuitive but using rollers and brushes, we will avoid overspray issues and apply a more even coat of paint on all surfaces. Crews will use spray equipment at the approach bridges because they can more easily access the surfaces to paint. Because the bridge is so large, and weather conditions that can change from day to day, painting will likely take most of the summer to complete.
During June, workers will complete installation of electrical systems within the bridge, including its lighting systems. During the planning process, residents living nearby said they wanted to avoid light pollution. We heard you. Bridge planners therefore chose to use energy-efficient LED lighting systems that illuminate the driving and walking surfaces of the bridge during nighttime hours but avoid giving off any significant ambient light.
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.
Restoration work around the 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. Others will complete Installation of ornamental railings and light fixtures. And painting operations will likely wrap up as well.
Although no official opening date has been determined, most on-bridge work should be completed by August. Before opening the bridge to traffic, we will need to make sure everything is completed as designed and in its proper place. During the months after the bridge opens to traffic, crews will need to landscape areas previously used for construction operations.
In addition to chomping at the bit to begin using this beautiful bridge, many people have asked us how we considered environmental impact when designing and building the St. Croix Crossing project.
We will discuss those topics in our next post. In the meantime, more information and photos will come by email, social media posts and the project website this summer.