Engineers reduce grade at dangerous Traverse City intersection using retaining walls

Retaining Walls Case Studies September 21, 2016
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For several years, the busy intersection of Lafranier Road and South Airport Road in Traverse City, Mich., near the Cherry Capital Airport was also one of the most dangerous. The steep, 12% grade at the end of Lafranier Road made it difficult for drivers to stop as they approached the South Airport Road intersection, especially during the winter months when icy roads made the intersection even more hazardous. As the condition of the roadway began to deteriorate over time, officials at the Grand Traverse County Road Commission (GTCRC) decided that, in the summer of 2015, it was time to give a 1.5-mile stretch of the road a much-needed update.

 

The main goal of the Lafranier Road reconstruction project was to reduce the grade of the hill leading to the South Airport Road intersection from 12% to 7%, while also widening the roadway to make room for a new center turn lane and pedestrian sidewalks on either side of the hill. The deadline for completion of the project was July 4, just in time to accommodate the influx of visitors to the City for the National Cherry Festival.

 

In order to make such a significant grade reduction to the roadway, the hill needed to be cut down by 12 ft, which would normally be done by building side slopes to keep the road stable during construction. However, the limited right-of-way on Lafranier Road did not allow enough space for side slopes, so designers decided on a retaining wall solution to stabilize the slopes for the project.

 

Having successfully used Redi-Rock on a similar project in the past, engineers at GTCRC chose the Redi-Rock gravity retaining wall system for the slope reduction project. Supplied by local Redi-Rock manufacturer, MDC Contracting, the Redi-Rock gravity system uses massive, 1-ton concrete blocks that stack together like giant Lego blocks to create strong, engineered walls without the need for reinforcement. Installation of Redi-Rock is quick and easy, and can be done within a tight footprint using an excavator and two-person crew, which was ideal for the limited right-of-way on this project.

 

Prior to construction of the retaining wall, contractors from Team Elmers had to lower existing utilities 10 ft to ensure they had enough coverage to protect against freeze-thaw cycles. When that was completed, they installed sheet piling to hold back the difficult 1-to-1 sand hill slope on each side of the roadway and support residential homes situated above. Then they excavated back to the sheet piling and quickly installed the retaining wall blocks in front of the sheets. In fact, “the guys did this in 7 days, which is unreal,” said project manager Al MacDonald.

 

In total, 1,300 Redi-Rock blocks in the Ledgestone texture were used on the retaining wall for the Lafranier Road project. Despite mid-project plan changes, the entire reconstruction project was completed ahead of schedule, and drivers now have a safer way to access the heart of Traverse City.

 

Find out how Redi-Rock can help on roadway projects at redi-rock.com/roads.

 

  • Retaining walls were used to hold back sandy slopes along roadway
  • Redi-Rock makes it possible for contractors to install in seven days
  • Ledgestone face texture on Redi-Rock blocks features natural-stone look
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