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Georgia DOT Improves One of the State’s Busiest Freight Corridors with I-16/I-95 Interchange Project

by: Larry Bernstein
Wick drains, also known as Prefabricated Vertical Drains (PVD), are geotextile filter-wrapped plastic strips with molded channels. These act as drainage paths to take pore water out of soft compressible soil so it consolidates faster. Wick drains are installed with specialized equipment called “stitchers” to approximately 30 feet depth. The earth embankment for the new I-95 southbound to I-16 eastbound bridge is the largest area of the interchange utilizing wick drains – over 1,600 wick drains will be installed.
Wick drains, also known as Prefabricated Vertical Drains (PVD), are geotextile filter-wrapped plastic strips with molded channels. These act as drainage paths to take pore water out of soft compressible soil so it consolidates faster. Wick drains are installed with specialized equipment called “stitchers” to approximately 30 feet depth. The earth embankment for the new I-95 southbound to I-16 eastbound bridge is the largest area of the interchange utilizing wick drains – over 1,600 wick drains will be installed.
An aerial view of construction progress of the I6@95 Interchange from I-95 looking to the northwest.
An aerial view of construction progress of the I6@95 Interchange from I-95 looking to the northwest.
Prefabricated vertical drains are installed to remove pore water from saturated soils to consolidate and improve the conditions of the soil prior to embankment construction. This photo shows the location of the embankment at the beginning of the new partial-turbine interchange bridge that will connect I-95 southbound to I-16 eastbound.
Prefabricated vertical drains are installed to remove pore water from saturated soils to consolidate and improve the conditions of the soil prior to embankment construction. This photo shows the location of the embankment at the beginning of the new partial-turbine interchange bridge that will connect I-95 southbound to I-16 eastbound.
A ground level view inside the northwest quadrant at the interchange of I-16 and I-95 showing construction crews installing bent cap forms for one of the new partial-turbine interchange bridges.
A ground level view inside the northwest quadrant at the interchange of I-16 and I-95 showing construction crews installing bent cap forms for one of the new partial-turbine interchange bridges.
A bird’s eye view of the 16@95 Interchange looking south along I-95 illustrating bridge construction activities as of March 15, 2021.
A bird’s eye view of the 16@95 Interchange looking south along I-95 illustrating bridge construction activities as of March 15, 2021.
Located on the Georgia coast, Savannah draws millions of visitors each year. Besides, those who are drawn to the southern town for its hospitality, architecture, and history, the city is also home to a bustling port as it exported more loaded containers than any other port in the country from January through May of 2020. The city’s economic development authority website notes that 70 percent of the U.S. population is within a two-day drive by ground, water, rail or air of Savannah. These facts are driving the Georgia Department of Transportation 16@95 Improvement Project.

The goal of the project is to improve traffic flow and enhance safety along I-16 and I-95. This is one of Georgia’s busiest freight corridors as it is the gateway to the port. The primary elements of the project include reconstructing the interchange at I-16 and I-95 and widening I-16 to I-516 to relieve traffic congestion.

Currently, the interchange is a full cloverleaf design. This was sufficient when the interchange was initially constructed nearly 50 years ago, but with current and future traffic volumes, a safer, more modern, and direct system to system interchange is needed. About 75,000 vehicles (20 percent is trucks) pass through the interchange daily.

“With the increase in freight traffic that is anticipated, this project provides needed enhancements not only for commercial vehicles, but also for the citizens and industries of the Coastal Empire,” says Darryl VanMeter, the Assistant Director P3 Division/State Innovative Delivery Administrator at Georgia DOT.

Multiple Elements
The project’s scope is vast. First and foremost is the new interchange design, which is commonly known as a partial-turbine interchange. Upon completion, it will be the first of its kind in Georgia. Two of the four existing cloverleafs will be converted into turbine ramps that cross over I-95 and I-16. “The new, innovative design will allow for traffic to move through the interchange at higher speeds with minimal impact to the existing interchange footprint,” VanMeter says.

The new bridges will move diverging and merging traffic away from the main interchange. This will minimize congestion and make the interchange operate more efficiently. The other two cloverleaf ramps that will remain open after construction are also undergoing minor improvements.

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Georgia DOT is also constructing a collector-distributor (CD) lane on I-95 northbound. The goal is to separate the vehicles exiting and entering I-95 northbound from the I-95 mainline traffic and allow unimpeded access from the I-16 cloverleaf ramps. It’s anticipated that the CD lanes will improve traffic flow, speed, and safety. Widening will also take place along the I-16 mainline corridor toward the inside median thus increasing the roadway from two to three lanes in both directions. The length of the additional lanes is approximately 6 miles.

Multiple bridges will be touched by the project. Six bridges are being reconstructed, four bridges are being replaced, and three bridges are being constructed including two flyover bridges that are part of the partial-turbine configuration.

Other elements of the project are geared towards safety and protecting the surrounding neighborhoods. After determining that noise barriers were needed in accordance with federal and state requirements, Georgia DOT surveyed the residents in the area to confirm their interest. As a result, the project will include three separate noise barrier walls ranging in length from 850 to 5,200 feet.

Lighting will also be improved in the area with the addition of state of the art, energy efficient LED lighting at the I-16 and I-95 Interchange.

Lastly, Intelligent Transportation Systems (ITS) technology is being installed. It includes cameras and changeable message signs for fast incident response and improved real-time communication with traveling motorists.

Environment Challenges and Preparation
As Savannah is on the coast, the area occasionally experiences hurricanes. Improvements for hurricane preparation are part of the project. The Georgia DOT will replace the two existing one-lane, emergency-use, median crossovers with one, two-lane, emergency-use median crossover. The length of the crossover lanes will be approximately 1,400 feet. This two-lane, emergency-use crossover will improve speed variation, improve logistics, decrease delay/congestion, and better prepare the region for an evacuation, which is one of the most demanding set of circumstances regarding transportation operations and management.
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I-95 and I-16 serve as evacuation routes for any declared emergency. In the event of a mandatory evacuation from coastal Georgia, the I-16 eastbound lanes become contraflow lanes in which all I-16 lanes will only support westbound traffic movement from Savannah to U.S. 441 in Dublin for 125 miles.

Between the Atlantic Ocean, the Savannah River and other waterways, the area is home to a tremendous amount of water which impacts the soil. “The design-build team is using excavator-mounted wick drain stitchers to accelerate the release of water stored in the soil. This drastically shortens the time it takes to compress the soft soils that are common in the area,” VanMeter says.

The wick drains are installed at various depths averaging 30 feet deep and are installed with specialized equipment called “stitchers.” Over 1,600 wick drains are being installed as part of the project.

Additional challenges faced by the design-build team include delivery of the project within a traffic congested location, physical constraints within the existing right-of-way, and commitments concerning environmentally sensitive areas. The design-build team is tasked with making every effort possible to avoid, minimize, and mitigate these challenges to successfully delivery the project.

On Time and On Budget
The lead contractor is SMC, a joint venture between Dragados USA, Inc. and Prince Contracting. Georgia DOT utilized the Best Value selection method to procure this project. The project is being delivered through design-build services, which requires SMC to complete all design and construction activities within an established time frame.

The budget for both design and construction services is over $260 million. While the project has been discussed for years, construction for the project began in the first quarter of 2020 and is expected be complete in the first quarter of 2023.

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When the project is complete, capacity will be increased and is expected to support up to 100,000 daily vehicles while alleviating over 30 percent of existing travel delay along the corridor. This project will also provide safer and streamlined, direct connections to and from the I-16 and I-95 interstate system. The safe, modern system will also support the growth of the port and improve the visitor experience from the beginning.

Photos courtesy of the Georgia Department of Transportation

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