Longfellow Bridge Inspection

Benesch provided bridge inspection services as part of a major rehabilitation for this historic 2,135-foot-long bridge spanning the Charles River, Memorial Drive in Cambridge and Storrow Drive in Boston.

The bridge carries four lanes of traffic for Cambridge Street (Route 3) and two Massachusetts Bay Transportation Authority (MBTA) Red Line tracks. The bridge consists of 11 spandrel steel arch spans ranging from 102 to 174 feet long, two steel stringer/floor beam approach spans, ten hollow piers and two hollow abutments with elevated roof slabs.

The underneath inspection of the main spans over the Charles River was done from a barge with a 60’ man lift chained to it. Approach spans were inspected at night with lane closures to access all areas. The inside of the pier and abutment chambers were accessed through manholes in the roadway.

Benesch prepared a rehabilitation report that included framing plans of each span, showing locations of all deteriorated steel to be replaced and/or repaired. The report also gave specific recommendations for construction staging for roadway and MBTA traffic during construction. The report was instrumental in the final design of the $70 million rehabilitation project.