CME led the design of this major bridge deck replacement project on I-91 in Springfield, Massachusetts. The project required a design solution for the rehabilitation of 129-spans of the viaduct structure that could be executed in two, major one-year phases affecting the mainline traffic.
Prior to construction, CME studied two major problems with the bridge framing. The viaduct has numerous fracture critical cap girders that had a history of cracking as well as numerous pin and hanger assemblies. After an extensive strain monitoring program, CME developed simple retrofit details to address the cracking and an innovative re-work of the pin and hangers, converting them into ship lap connections. This eliminated the pin and hangers and addressed the deterioration behind the hanger plates.
CME also provided an innovative idea for addressing corrosion damage, saving months of time during design development and resulted in very cost-effective repair details.
CME completed the structural design for the replacement of the concrete deck for approximately 1 mile of contiguous bridge structures that carry I-91 over a network of at-grade roadways in Springfield, Massachusetts. This elevated highway corridor known as the Springfield Viaduct, features 67 spans supporting 320,000 square feet of deck area in the northbound lanes and 62 spans supporting 290,000 square feet of deck area in the southbound lanes. The project limits included I-91 northbound and southbound, just south of State Street and end in the vicinity of the I-291 Interchange ramps. Rehabilitation of various on and off ramps between these limits and the I-291 ramp structures was also included in this project.
This high-profile, $165 million project involved the replacement of the deck and widening of the left and right shoulders to accommodate new lighting and improved drainage structures. These features incorporate Best Management Practices (BMPs) to mitigate impervious highway cover and meet Waste Load Allocations in accordance with MassDOT’s Impaired Water Program. The BMPs help to improve water quality in the Connecticut River through better treatment of storm water runoff from the highway which runs parallel to the river.
The project was constructed in three primary stages to accommodate traffic through the work zone. The initial stage included the preparation of the city streets and minor widening to the structure. The two major stages include the closure of all on and off ramps to the structure while maintaining two lanes of traffic in either direction through the viaduct.
CME was selected to prepare the entire structural design for this project. In addition to replacement of the bridge deck, other bridge design work involved the replacement of approximately 450 high load multi-rotational (HLMR) bearings, the on-bridge drainage structures, steel repairs, retrofit (elimination) of 161 pin and hanger assemblies, and repairs to the substructure.
To expedite the project, CME proposed Accelerated Bridge Construction methods using longitudinal precast deck panels to reduce the construction schedule from 6 years to 3 years. Following bid selection, the Contractor elected to use a standard cast-in-place deck but employed other methods to meet the accelerated project schedule.
The project also included full removal of the existing paint system on the steel girder and painting. CME worked closely with MassDOT during design and construction to develop special provisions that provided for detailed measurements of the deteriorated steel during construction and after blast cleaning. This method was developed based on experiences on other recent projects where deterioration was not accurately depicted, and the rework of steel repair plates caused delays to the project. At the end of the project, this method proved to be an innovative and cost-effective way to rehabilitate the steel.