General Edwards Bridge
The General Edwards Bridge is a multiple-span steel-girder bridge over the mouth of the Saugus River where it flows into the Atlantic Ocean. The central moveable span over the main navigation channel is a four-leaf, rolling-lift, bascule girder configuration that uses heavyweight concrete counterweights that are not enclosed in the bascule-span piers. In 2003, a seven-ton section of concrete fell from the counterweight into the water. SGH performed a condition assessment and designed emergency and permanent repairs.
The bridge was constructed in the mid-1930s and had undergone several major renovations prior to SGH’s involvement. Following the incident in 2003, SGH investigated the condition of the four counterweights and found deteriorated outer concrete on all counterweights. We provided temporary repairs to keep the bridge operable and developed permanent repair procedures and contract documents for rehabilitation.
For the emergency repairs, we designed a wrap of steel rope and fabric mesh that was placed around each counterweight to act as a temporary safety measure to allow the bridge to remain operable.
For the permanent repairs, we developed a repair that utilized the sound heavyweight concrete in the central cores of the counterweights and replaced only the outer deteriorated concrete on the sides and bottoms of the structures. We also designed new rack-type structures attached to the trusses to hold permanent steel ballast plates and incorporate empty “pocket” areas for the installation of coated lead weight-adjustment blocks.