NHDOT Reconstructs, Modernizes Structurally Deficient Bridges on I-93

Fri August 22, 2008 - Northeast Edition
James A. Merolla



SPS New England Inc. has begun the greatly anticipated reconstruction of the Interstate 93 Exit 1 interchange at Rockingham Park Boulevard in Salem, N.H.

The existing Exit 1 Interchange at Rockingham Park Boulevard in Salem is the first of five interchanges to be reconstructed under the Rebuilding I-93 project.

The $23.7 million first phase contract for construction of the Exit 1 ramps and bridges involves the replacement of the Exit 1 southbound on/off ramp bridges over the I-93 northbound and southbound barrels, as well as the rehabilitation of the ramp bridges over South Policy Street. These seven existing bridges have been determined to be structurally deficient and are therefore designated as “Red List” bridges.

The seven bridges on this first project phase are included on the agency’s “Red List” of 140 bridges with such low Federal Sufficiency Ratings (FSR) due to poor conditions, weight restrictions, or type of construction, that they must undergo two inspections each year.

The four existing bridges over northbound and southbound I-93 will be consolidated into two single-span bridges. The two existing northern bridges over South Policy Street will be rehabilitated, including replacement of the structural steel and concrete deck. The southernmost bridge over South Policy, carrying the northbound off-ramp, will be realigned and rehabilitated, including replacement of the structural steel and concrete deck and replacement of the piers. The ramp approaches to all the bridges will be reconstructed. The project is slated for completion in August.

“Our project is just one phase of a major initiative by the State of New Hampshire to widen Interstate 93 from Salem to Manchester from two lanes to four,” said SPS Senior Vice President Tim McClaughlin. “Our project involves the realignment of the Exit 1 ramps and the replacement of six ramp bridges. The bridges will be lengthened to allow for the future widening of the mainline highway. The work includes the complete rebuilding of the exit ramps with new drainage systems, wetland alterations, pavement, signs and safety features. Sound walls are also being built for the benefit of the abutting neighborhoods.

“After the shifting of traffic, demolition is performed on the existing bridges and they are then reconstructed from the ground up. Various foundation methods will be employed including preloading of the existing soils, ground improvement methods, mechanically stabilized earth walls, and driven pile foundations. The project is approximately 35 percent complete.”

Forty Years of Neglect

Overall, reconstruction along the exit will involve 8,900 ft. (2713 m) along southbound I-93 on/off ramps; 3,000 ft. (914 m) along northbound I-93 off-ramp; and 400 ft. (122 m) along South Policy Street. A sound wall will be constructed along the eastern side of the northbound off-ramp along the back side of properties located on Macgregor Avenue and Maclarnon Road.

According to NHDOT, the contract for the replacement of Cross Street Bridge over I-93 and related improvements to the roadway approaches is more than 85 percent complete. The new bridge is being installed about 80 ft. north of the existing bridge. The existing bridge will be demolished and removed soon. The structural steel has been set over northbound and southbound I-93, and pre-cast concrete decking has been installed. This bridge replacement project replaces a Red-Listed structurally deficient bridge built in 1961.

The structural steel for this bridge consists of five girders, each made up of five pieces and four adjoining splices. When connected together, each girder is a total length of 420 linear ft. (128 m). The total weight of structural steel for this bridge is 945,000 lbs. (428,644 kg).

Under the SPS contract, ramp approaches will be reconstructed to tie into the new bridges. In addition, the job entails building a wood panel and concrete post sound wall along the easterly side of the northbound on-ramp.

Work this summer construction season included site clearing and preparations for bridge construction from June to August. Most of the bridge construction and ramp realignment work will take place in 2008-2009. NHDOT said widening the entire 20-mi. section of I-93 is necessary to reduce congestion and improve safety, a project that began in 2006 and will be completed in many phases through 2014.

Built in the 1960s to accommodate 60,000 to 70,000 vehicles per day, the highway now experiences more than 100,000 vehicles per day in Salem, with segments between Exits 2 and 5 carrying up to 80,000 vehicles per day.

The overall project will add two travel lanes in each direction over the entire 20-mi. segment and improve the five interchanges south of Interstate 293 to the state line. All told, 20 bridges will be replaced and 23 will be rehabilitated or widened. New park and ride facilities at Exits 2, 3, and 5 will be built and space within the median will be reserved to accommodate future commuter rail trains

In addition, bus service and other commuter ride-sharing opportunities to Boston and northern Massachusetts will be expanded and enhanced. The overall goal is to modernize the road system by upgrading the aging infrastructure to provide safer driving conditions, thus increasing mobility by offering flexible commuting options. But that is literally down the road.

Work on Exits 2, 3, 4 and 5 are in the development and planning stages.

Going forward toward the next phase, work in Londonderry, involving the reconstruction/reconfiguration of Exit 5 southbound on and off-ramps and the northbound on-ramp has passed the contract bid stage and this project was awarded to Severino Trucking Company of Candia, N.H., on June 25. Construction begins in July and is expected to be finished in November 2009 at an estimated total cost of $16.1 million.

Most Ambitious Project

The widening of a 20-mi. segment of I-93 between Exits 1 and 5 from the Massachusetts state line to Manchester, N.H., is one of the most ambitious projects that NHDOT has ever undertaken.

Projections indicate that traffic will increase to 140,000 vehicles per day in Salem by the year 2020. NHDOT and the Federal Highway Administration (FHWA) decided to widen the highway after carefully reviewing several construction alternatives and their environmental, social, economic and cultural impacts on the southeastern New Hampshire region. Wider is safer, they say.

Rebuilding I-93 is more than just a roadway and bridge construction project. NHDOT and FHWA have invested in several other concurrent initiatives that will continue to maintain and improve the quality of life in New Hampshire. These initiatives include:

• The Community Technical Assistance Program (CTAP) will help communities meet the wide range of challenges faced in the I-93 corridor by providing technical assistance and access to tools for innovative land use planning.

• NHDOT’s Intelligent Transportation Systems and Traffic Incident Management programs will help improve safety, ease congestion, and improve traffic related information to the public.

• The Transit Investment Study is looking at alternative means of providing transit through the I-93 Corridor.

• The Accelerated Construction Technology Transfer workshop investigated and evaluated ways to speed up the rebuilding of I-93 to help save taxpayers dollars and minimize disruptions to the traveling public and communities.

• The NHDOT is working to protect the environment through wetland mitigation. They have committed $3 million in funding to the NHDES Drinking Water Supply Land Grant Program, $3.5 million in funding for CTAP to assist communities by addressing growth and development associated with the corridor improvements, and with the NHDES to conduct a chloride surface water quality study.

• I-93 provides a critical link between the communities in south central New Hampshire and the greater Boston metropolitan area. When completed, this project will dramatically improve this important stretch of highway, reducing congestion and increasing safety for decades to come.

Construction started in 2006 with the Exit 4 Park-and-Ride Bus Terminal and is now well under way at other locations.

Although rail options were considered, it was clear that widening of I-93 was required to address existing traffic congestion, the condition of the aging infrastructure (bridges) and safety concerns. Preliminary study of rail ridership indicated that the addition of rail would not significantly reduce the traffic volumes on I-93.

However, NHDOT is not precluding the addition of rail in the future or providing other means of public transportation. All improvements to I-93 will be done to allow future rail service to be constructed within the highway corridor.

When construction started on the Exit 1 ramps and bridges in the fall of 2007, it was the first Smart Work Zone in the state. SMZ is part of the Intelligent Transportation Systems, and is implemented by using dynamic message signs that relay information. A camera also provides real-time traffic information to the public Web site and the Transportation Management Center. CEG