A new two-lane tunnel is being constructed under the Elizabeth River, in Portsmouth and Norfolk, Virginia. The current Midtown Tunnel connects Portsmouth and Norfolk, Virginia. The project involves construction of a new Midtown Tunnel adjacent to the existing one between the cities of Norfolk and Portsmouth. The plans also include rehabilitation of the existing Downtown and Midtown Tunnels, and extension of the Martin Luther King (MLK) Expressway to I-264.
Currently, more than 120,000 drivers use the two-lane tunnel to cross the Elizabeth River daily. Hampton, Newport News, Portsmouth, Virginia Beach, and Norfolk are home to thousands of military families along with civilian workers supporting our armed forces and the shipbuilding industry. This very popular region has seen tremendous growth resulting in traffic congestion as an accelerating problem to commuters in this area. Since the tunnel was originally built 50 years ago, population has increased nearly 70%, and tunnel usage has gone up by 600%.
Construction of new tunnel
As part of President Obama's vision of an American built to last, the $2.1 billion project relies on a $422 million Transportation Infrastructure Finance Innovation Act (TIFIA) loan awarded by the Department of Transportation in April 2012. TIFIA is further secured by a fully funded debt service reserve fund. The loan will be repaid with toll revenues. The new Midtown tunnel is being built through a Public Private Partnership between Virginia Department of Transportation (VDOT) and ERC.
The ERC company is a 50/50 joint venture of Sweden based Skanska a construction company Australian based Macquarie toll road financiers and owners. ERC will toll, develop, operate and maintain the tunnels for 58 years under a concession agreement.
The tunnel presently has three tubes of 2 lanes each, twin tubes at the Downtown Tunnel and a single tube running one lane each direction at the Midtown Tunnel. Under the concession agreement Macquarie/Skanska's ERC is adding a 4th tube of two lanes to the Midtown Tunnel.
Construction started with the tunnel rehabilitation in mid-2012. Groundbreaking for the new underwater tunnel began in January 2013, which involves element fabrication, dredging, excavation support and pile driving. Timber pilings are used to support the turbidity curtains, installed around Dredge Units 1, 2, and 5 during dredging and excavation operations.
International Construction (ICE®) specially manufactured a bottom drive with segments of sheets separated by an HBeam to drive king piles using the ICE® I-66 Vibratory Hammer. The need to drive multiple sizes of the king piles for the water barrier was a high priority for this project.ICE® service experts designed and manufactured the custom guides to allow multiple king piles to fit in the leads. The king walls were configured by sheet piles separated with "I" beams that are in pairs to support the wall. ICE® engineers customized a cap that is put in place in order to fit the wall to the hammer, enabling one hammer to be used with the different king walls. Removable inserts were used to accommodate multiple king pile configurations. The sheets were vibrated in pairs using an adapter plate between the clamps and hammer in order to position the clamps to the proper place so that multiple sheets can be driven.
Tube elements will be immersed in middle to late 2014 with a total of 11 immerse tube elements from Portsmouth to Norfolk. Each immerse tube element is 55ft wide, 29ft high and more than 300ft in length. The tubes will be constructed at Sparrow point, Maryland and then transferred to the site. Waterproof membrane will protect the element from water leakage.
With expected completion date or all phases of this project by 2017, the new adjacent Midtown Tunnel will double its capacity bringing overdue relief to commuters by saving an average of 30 minutes per trip. The extension of the MLK Expressway, will allow drivers to easily access both tunnels, saving them time and frustration, cutting fuel costs and greenhouse gas emission as well. In addition, upgrades to the existing Midtown and Downtown tunnels will provide safer travel as improvements to the Downtown Tunnel will bring it into compliance with current fire and life safety standards.