Title
Discussion of Wall Design for the MARTA Pine Grove Road Sidewalk project - Guidance
Body
Action Required:
Guidance
Description:
One of the MARTA Offset Pedestrian Projects currently under design is along Pine Grove Road/Magnolia Road near the Coleman Road intersection. Mulkey Engineers has prepared the concept layout and identified the need for a wall. Knowing the importance of saving trees, staff and the consultant have investigated alternatives to minimize the impact to existing trees.
The attached concept shows the location of the wall - along the north side of Magnolia Street, just east of Coleman Road. The Marirose property is heavily vegetated and has one residential home. The typical section graphic (attached) shows the 2-foot bike shoulder, 2-foot curb, 2-foot grass strip, 5-foot sidewalk, and retaining wall (varying from 5 to 9 feet tall).
Instead of a standard GDOT cantilever wall, staff recommends installing a soil anchor wall. The construction of a standard cantilever wall requires a cut slope into the Marirose property which will require removal of approximately 36 trees. Alternatively, a soil anchor wall consists of drilling into the vertical slope and installing anchors to hold back the soil, and then connecting these anchors to a specially designed modular block wall. The benefits to this method are:
• Reduced cutting into hillside of the Marirose property
• Estimated 13 trees removed compared to 36 trees
• Allows for different wall aesthetic looks Cantilever Wall construction cost is approximately $120,000
• Soil Anchor wall construction cost is approximately $130,000, plus the wall design fee (estimated to be $8,000 to $10,000)
Prior to designing the wall and finalizing the construction plans, staff seeks feedback on the recommended wall design. This will avoid any surprises during construction and will keep the project on schedule.