Rehabilitation of the Neponset River Bridge
Location: Boston, Massachusetts
Contract Value: $5,815,000
Project Dates: March 2011 – September 2013
MBTA Contract H74CN08 includes the replacement of the Neponset River Bridge on the Fairmount Commuter Rail line. The bridge, built in 1906, is an open deck steel plate girder structure with two spans. The bridge carries two mainline tracks.
The work involves the complete replacement of the bridge. The proposed main line track bridge will be a single span ballasted steel plate girder structure supported on drilled shaft footings drilled behind the existing abutments. The center pier has considerable deterioration and will be reinforced to carry the service load during construction. The outbound track will be shutdown to facilitate replacement of the bridge and construction of drilled shafts as part of Phase I work. Once complete, service will be restored on the outbound track bridge and inbound track bridge will be shut down for the Phase II work. The center pier will be cut below the mud line after the new bridge is in place.
Phase I work, which involves replacement of outbound track bridge, is scheduled to be completed by March 2012; and Phase II work, which involves replacement of inbound track bridge, is scheduled for completion by March 2013.