MassDOT photo. Looking west, crews work on the pier caps atop the center pier columns within the I-95 median for the new Route 2 East bridge.
Personnel from SPS New England Inc., the general contractor and DW White Construction Inc., the earth and roadwork subcontractor, are making steady progress to meet the Massachusetts Department of Transportation's (MassDOT) substantial completion November delivery date for the design-build Route 2/I-95 Bridge Replacement Project. Crews are replacing the existing bridges carrying Route 2 east and westbound over I-95 in Lexington, also called the Concord Turnpike.
The $60 million contract was awarded in February 2014 and crews began the work in May 2014. The bridge and associated roadway reconstruction at the Route 2/I-95 interchange is being funded by 80 percent federal and 20 percent state dollars.
The project, in the town of Lexington, is part of MassDOT's ongoing program to replace aging highway infrastructure that was built during the building boom of the 1960s. The work area goes from Old County Road in the west near the Lincoln town line to Spring Street in the east, and is close to many high tech and biotech businesses.
“It also abuts the watershed of the Cambridge reservoir, the main water supply for the city of Cambridge,” noted the Web page of the project, which requires that the work respect environmental concerns.
Route 2 is one of the main alternatives to the Massachusetts Turnpike for east-west travel and carries approximately 67,000 vehicles per-day.
“The bridges, built in 1960, are structurally deficient and functionally obsolete, and the vertical clearance for I-95 under the bridges is substandard,” noted the Web page. “The project will address the bridges' current structural deficiencies, upgrade their capacity, meet current seismic criteria, improve safety, protect the environment and reduce annual maintenance costs. Accelerated Bridge Construction [ABC] techniques will be used to minimize disruption and reduce construction duration. They include the first-time use in Massachusetts of precast, modular concrete abutments instead of a deep foundation system using numerous drilled shafts.”
The work is complicated and varied, and requires serious planning throughout its many stages as the replacement bridges consist of two 334-ft. (101.8 m), two-span steel plate girder structures. The new bridge cross sections will provide three 12-ft. (3.65 m) travel lanes, one 12-ft. auxiliary lane and two 6-ft. (1.8 m) wide shoulders in each direction. MassDOT is also realigning and reconstructing portions of Route 2 to improve clearance over I-95 to 16.5 ft. (41.91 cm), making it easier to stage the construction.
Also included are an upgraded storm water drainage system, treatment and architectural elements, landscape restoration to improve aesthetics and the resurfacing of a 2-mi. (3.21 km) section of I-95, which includes reconstructing the median; upgrading and replacing guard rails; widening shoulders; installing new pavement and markings; and improving storm water drainage.
“The project features MassDOT's first use of 'Intelligent Compaction.' Compaction is one of the most important processes in roadway construction for high quality, uniform, long-lasting pavement,” noted the project's Web page.
This construction method employs vibratory rollers equipped with an on-board computer reporting system and global positioning system (GPS) mapping. This provides the operator with an on-board, real-time record of the location and number of roller passes, as well as compaction data.
The bridge and highway design was complete last April by TranSystems Corporation, the design lead. It was assisted by Haley & Aldrich for Geotechnical Engineering, and Green International Affiliates Inc. for landscape architecture and utilities. Regina Villa Associates Inc. assisted MassDOT with the public outreach component.
The project is currently at 64 percent complete. The new westbound Route 2 Bridge (carrying eastbound traffic during Phase 2 construction) is complete, with the exception of final wearing surface and the glandular type strip seal joint system. Construction of the new eastbound bridge has progressed rapidly with the favorable winter weather conditions experienced this year. The cast-in-place concrete deck was placed on March 19, 2016, and work is continuing on the barrier walls, end walls and other miscellaneous components of the bridge.
A few of the challenges encountered during construction include the high traffic volumes on I-95 and Route 2, and coordinating the work around those high volumes and adjacent projects.
“Communication with project staff and other DOT project personnel on adjacent contracts, and the general public is vital to minimizing traffic disruptions and schedule delays,” stated MassDOT in response to various questions concerning the project's progress. “Bi-weekly project meetings keep the lines of communication open and assist all parties in resolving technical or construction issues that arise during the design-build process.
“The goal of any new or replacement bridge design project,” added MassDOT, “is to provide a structure that has been designed in accordance with the latest applicable AASHTO LRFD and MassDOT Bridge Manual requirements for design and load carrying capacity and which can reasonably be expected to achieve a minimum service life of 75 years. We do this by incorporating MassDOT standardized structure detailing that has proven effective under service, strength and maintenance considerations, and by using new high-performance concrete and steels that aid in reducing long-term maintenance and extending the service life of the structure.”
This project will require the use of 9,475 tons (8,595.5 t) of concrete, 577 tons (523.4 t) of rebar, 1,096 tons (994 t) of structural steel, 78,100 tons (70,851 t) of asphalt, and 5,850 linear ft. (1,783 m) of RCP drainage pipe.