A North Carolina road construction project is helping prevent soil erosion and helping make roads safer in a heavily traveled area
While Raleigh is known as North Carolina’s capital, the “City of Oaks” is also making a name for itself as one of the fastest growing cities in the country. With its steady rise in population comes the need to upgrade infrastructure, including roads and highways as traffic becomes more crowded. One of Raleigh’s busiest sections is situated on a stretch of I-40 between the I-440 beltline and the suburbs in Johnston County.
Anticipating future growth in the area, the North Carolina Department of Transportation (NCDOT) decided to make some updates to this busy stretch. The team at S.T. Wooten was chosen to help manage a major widening and redesign effort to improve traffic conditions and ensure safety for the rising number of travelers in the section. The project covers nearly 13 miles of the highway extending from the I-440 divide in Raleigh to two miles east of the busy N.C. 42 interchange in Johnston County.
Nearing the halfway point of the project, which began in 2018, much of the focus has been on repairing and replacing the underlying storm drain. A number of innovative techniques have been used to get the work done efficiently while supporting overarching goals.
Reviewing the Game Plan
For the I-40 design-build project, S.T. Wooten is adding two new lanes in each direction of the highway – extending four-lane sections to eight lanes and six-lane sections to ten lanes. In conjunction with road widening and paving efforts, crews are repairing and upgrading the storm drain systems under the full stretch of highway to improve flood protection and erosion control.
To ensure efficiency and help keep momentum moving on the project, the work zone was broken up into six separate sections with different workflows happening simultaneously in each area. For example, crews started construction on the median storm drain in the first section before moving to outside and inside lanes. Traffic was pushed to opposite lanes during this process. In the second section, crews started on the outside lane and transitioned across to the inside lanes.
Project managers have had to keep a close eye on work schedules and be flexible when necessary. A master plan helps keep the team on track with overall objectives, but work can vary week to week based on factors like the weather or supplies.
To Repair or Replace? Going to the Video Replay
S.T. Wooten has been working closely with the NCDOT to inspect each section of storm drain and decide whether it will need to be repaired or fully replaced before moving forward with construction. To do this work efficiently and with minimal disruption in the work zone, S.T. Wooten tapped Nu-Pipe to assist with video technology. Running cameras through the pipes helps to give crews a clearer picture of what’s happening inside.
This process starts with a flushing procedure done with a high-powered jet system that blows water through the system to remove foreign debris and material from the pipes. Once the removal of any built-up silt and debris is complete, technicians move a small camera truck through the pipes to help get a look inside. The camera consists of a rotating head that captures a 360-view, even along the joints, so crews can fully assess conditions and pinpoint any deficiencies.
The team then submits a recommendation for the NCDOT to approve based on the video data captured during the storm drain inspection. Some have required full pipe replacements, while others have called for us to install new liners.
A New Play: Using UV Liner
Crews have installed three different types of cured in-place pipes to upgrade existing storm drain systems currently functioning on the project. Spin cast liners and water curing methods have been used, which are pretty common in the industry. However, the third technique applied in some locations – UV liner – is a more advanced approach that utilizes ultraviolet light to cure the liner. The I-40 project marks the first time this UV liner method has been used on a project for the NCDOT.
The system involves pulling a fiberglass-reinforced polyester liner, attached with a special resin through both ends of the drain pipe. Crews then run a UV light through the inside to cure the resin, which helps form a strong “pipe inside the pipe” that is more durable and able to protect against wear and tear. This process also better serves the surrounding environment because no water has to pass through in the curing process, which could carry along potential contaminants.
Crews made additional upgrades to the storm drain systems that will improve their function along the highway corridor. Larger diameter overflow lines have been installed adjacent to existing storm drain lines to help accommodate increased future drainage throughout the project.
Similar to our initial inspections, video technology has also been used for reviewing our work in hard-to-reach locations. Using our own cameras, crews were able to inspect the newly installed pipes without having to disturb the area. It’s an efficient way to ensure a quality final product.
While every construction job has its challenges, the ability to plan ahead and be strategic has served teams well on the I-40 project. Getting creative with technology has also helped execute the game plan and keep momentum moving forward towards the 2022 target deadline. Having the right Xs and Os in position will help the team continue its march toward the goal line, one that will be welcomed by travelers in the growing city of Raleigh.