Improving Connectivity with a Tunnel

Posted by on Aug 21, 2018

By: Alicia Bailey, P.E. 

If you have been on Shelby County Road 41/Dunnavant Valley Road near the Town of Mt Laurel lately, you have probably noticed a lot of construction.  A gas station, grocery store, and other retail stores in the Dunnavant development will provide the area with new shopping and eating options.  In addition to the retail stores, construction activity has included infrastructure improvements to enhance connectivity and options for travel within the community.

A lot of teamwork has gone into designing and constructing the development.  The project required the services of site, roadway, structural, geotechnical and utility engineers as well as surveyors, architects and landscape architects.  All parties worked together along with the developer, contractor, utility companies, and approving agencies to complete the project.

In many ways County Road 41 (CR 41) acts as a barrier between the Town of Mt Laurel and the Dunnavant Square development.  Lots of vehicular traffic moving at high speeds can make it difficult to cross the highway.  The development team needed to figure out how to effectively and safely get people from one side of the road to the other. Mt Laurel has a sizable number of people who walk, bike and ride golf carts within the community.  Each of these travel modes needs a safe way to cross the highway and that crossing needs to be connected to the existing sidewalk system.

Out of these challenges was born the idea to tunnel underneath CR 41. A tunnel to accommodate pedestrians, bicycles, and golf carts would be needed.

The first step to developing a tunnel was to evaluate its feasibility to be constructed under the existing highway.  Consideration was given to drainage (how to keep water out of the tunnel), right of way and utility impacts, tunnel size, retaining wall locations, aesthetics, and cost.   Several options were reviewed and evaluated before a final layout was recommended.

Next, the engineers and contractors had to figure out how to build it.  CR 41 is a highly traveled roadway; shutting down the road and detouring was not desirable.  Working with the County and contractor, Sain determined a temporary diversion route could be constructed to shift traffic off the existing highway to allow room to dig the deep hole and install the tunnel and retaining walls while maintaining traffic flow.

Aesthetics of the improvements were of high importance.  The retaining walls have stone veneer, sidewalks have brick pavers, guardrail and barrier rails are painted to improve their appearance, and landscaping is installed.

The soon to be opened Dunnavant Valley tunnel accomplishes the goal of providing safe accommodation for pedestrians, bicycles, and golf carts to cross CR 41 and improves connectivity in the greater Mt Laurel community.  A golf cart parking area is even provided!

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