Midtown Tunnel, Hampton Roads, VA

08.03.2017
 
The tunnel is being built in Sparrows Point, MD, due to the availability of a large dry dock.

 

Since the time the Midtown Tunnel was built under the Elizabeth River in 1962, population in the
Hampton Roads region of Virginia has increased nearly 70% and tunnel usage has gone up by 600%.

Today, this vital link between the cities of Norfolk and Portsmouth carries almost 1 million vehicles a month and is the most heavily traveled two-lane road east of the Mississippi River. Congestion is costing millions of dollars in lost time, productivity and economic development.

Construction of a new Midtown Tunnel began in 2013 to enhance traffic flow, improve safety and improve connectivity within the region. The new 4,800-foot, two-lane tunnel, which will be located adjacent to the existing 50-year-old Midtown Tunnel, will provide a separate roadway that allows two lanes of traffic in both directions and double transportation capacity beneath the Elizabeth River.

The construction team is building the box culvert tunnel in Sparrows Point, MD, due to the availability of a large dry dock. The tunnel tube will consist of 11 reinforced concrete elements, each comprising five sections requiring separate concrete pours. At the fabrication site, Lafarge has two portable plants to produce 72,000 cubic yards of Agilia® self-consolidating concrete for the 55 concrete pours. Agilia® was selected due to the massive amount of structural steel and the need for thermal restrictions. The mix uses 65% slag replacement and there is a need for a 30°F drop in concrete temperature to prevent thermal cracking. Lafarge is also supplying 19,332 tons of slag and 60,000 tons of aggregate for the project.
 

 

 

Tunnel Element

 

Each 16,000-ton concrete tunnel element measures approximately 350 feet long, 55 feet wide and 28.5
feet high. Once complete, the tunnel elements are towed one at a time by a tug fleet 220 miles down
the Chesapeake Bay to the Portsmouth Marine Terminal. The first six tunnel elements arrived at the
project site in summer 2014, where they will be moored in preparation for placement in the Elizabeth
River beginning in fall 2014. The construction team in Sparrows Point has begun producing the
remaining five tunnel elements, which are scheduled to arrive in Hampton Roads harbor in spring 2015.

The new Midtown Tunnel will offer broad and lasting benefits to the Hampton Roads transportation
system, its economy, and the lives of those who live and work in the region. When the project is
completed in 2016, the existing 50-year-old tunnel will be rehabbed, after which the side-by-side tubes
will carry two lanes of traffic in each direction. The average round trip user will save about 30 minutes a
day, roadway safety will improve with the elimination of bidirectional traffic, and increased capacity will
support the movement of goods in and out of various port facilities in the region.