Virginia DOT Decreases Weaving and Travel Time with I-64/I-264 Interchange Improvements
Redistributing Traffic: I-64/I-264 Interchange Improvements Bring a Safer, Smoother Ride to Hampton Roads Area
It’s said that all roads lead home, and while that may be true, some roads lead home more directly than others. The I-64/I-264 interchange improvements in the Southside Hampton Roads region of Virginia will help to provide commuters a safe and efficient path home, or whatever their destination may be.
The large project, which was split into two phases because of its size and partially because of the availability of funds, has a two-fold purpose: to decrease the travel time and to enhance safety by adding lanes to reduce conflicting weave patterns. The I-64/I-264 corridor is the second busiest in the Commonwealth of Virginia. Because it serves as a gateway to Virginia Beach, it’s particularly busy during the summer months. The average daily traffic on the corridor is roughly 100,000 vehicles.
Commuters regularly experience congestion delays in the greater Hampton Roads area. To enable a quicker and safer ride, the Virginia Department of Transportation (VDOT) is giving local commuters another option. “The goal of this project is to separate interstate traffic from local traffic,” says James Klotz, VDOT Construction Engineer for both Phase I and Phase II.
Klotz, the Commonwealth’s engineer responsible for both projects and the principal point of contact, makes field- and project-level decisions on the Commonwealth’s behalf. “The project allows motorists the option to either use the interstate route to Virginia Beach or to use collector-distributor (CD) lanes for local traffic,” he says.
VDOT is taking a number of steps to facilitate the redistribution of traffic. During Phase I, I-64 west was widened to include a second exit lane, carry two I-264 west CD lanes from Military Highway over a newly constructed bridge, and new bridge ramps (one for interstate and one for local traffic) from I-64 west to I-264 east were also added. Where there once was a single exit lane and ramp from I-64 to I-264, there are now two exit lanes and three major bridges.
In Phase II of the project, a new system of collector-distributor lanes are being added on I-264 east. The CD lanes will run from Newtown Road to Witchduck Road, parallel to the interstate. Two bridges on I-264 east are also being widened: over Newtown Road and an abandoned CSX rail line.
Further, a new flyover across I-264 is being built to enable local traffic to go from the north side to the south side of I-264 without actually getting on the interstate.
At the Witchduck Road interchange, an off-ramp is being installed from I-264 east to replace the existing Exit 15b off-loop. The ramp will feed into the Witchduck Road and Grayson Road intersection. Further realignment at the intersection will convert the current five-point intersection into a four-point intersection. “Because there will be less conflict points, traffic will be able to flow faster and safer,” says Klotz.
Klotz adds that since the completion of Phase I bridges, CD lanes and exit lanes, motorists have commented that they have experienced a greater ease of movement, less weaving and a decrease in travel time from the Twin Bridges to Newtown Road.
Challenges and Unique Elements
There are multiple challenges associated with building in the area due to the poor quality of the soil. “The soil in the area is clay and what was deposited by the oceans from years ago,” says Klotz. “It’s not good soil to build on as there are areas of high expected settlement predicted throughout the site.”
To achieve an acceptable level of settlement, the process of installing wick drains, followed by surcharging is specified throughout the project. The drains provide drainage paths for pore water in the soft compressible soil and the surcharge places weight on the wicked area to force the water to come up the surface and allow the soil to settle.
In addition, mechanically stabilized earth wall ramps are being constructed to align roadways and bridges. Klotz described the construction of MSE walls: “It’s like making a cake, layer by layer.”
Both phases of the project utilized drilled shafts as deep foundations for the vertical columns and horizontal pier caps that support the bridges. To date, 145 shafts were installed in Phase I and 12 are slated for Phase II. The steps in the drilled shaft construction can be summarized as: Drill the shaft hole into the ground, fill the hole with a polymer slurry to equalize cave-in pressure, lift and lower a steel-reinforcement cage into the slurry-filled shaft, and fill it with concrete. As the concrete displaces the slurry, the slurry is recycled for subsequent shafts.
Construction on Phase I bridges and ramps began in November 2016 and is currently finishing up. Construction of Phase II began in March 2018 and is scheduled to be complete in fall 2021.
VDOT has special provisions for cost-loaded contract progress reports that are updated on a monthly basis, to track the progress of work. As the contractor executes work, costs associated with the work are plotted against time and compared to the projected early, on time and behind schedule rates of production. Klotz credits this method of tracking progress as the contractor solely provides the data used to generate the production rate curves. With this in mind, VDOT can identify areas where the contractor may improve their level of performance.
Over the course of the Phase II project, there have also been some changes. The contractor proposed an earthen-filled roadway rather than a structural bridge that was part of the original plan. The freeboard (distance from the water surface to the bottom of the bridge) on the original planned bridge was minimal.
Because the area is susceptible to flooding and tidal fluctuations it was agreed that a fill structure be constructed rather than a bridge structure. Klotz and his team, along with several stakeholders, reviewed the design proposed by the contractor and ultimately allowed the change to go through.
Another change, the realignment of a local road, afforded the contractor earlier access to an expected high-settlement area.
The combined construction budget for both projects totals $263 million.
Phase I was funded by Hampton Roads Transportation Accountability Commission (HRTAC) funds as well as from federal and state resources. Phase II also relies on HRTAC funds, as well as state, federal, and City of Virginia Beach resources.
Upon completion, the I-64/I-264 interchange improvements project in Southside Hampton Roads will help to improve mobility and enhance safety through this highly traveled corridor. Safer, more efficient – and everyone is on the road that leads to their destination.