MBTA required Barletta to remove the existing bridge during one five-hour overnight shift. To accomplish this, Barletta would have to remove the bridge in a single heavy lift. SGH evaluated the feasibility of this approach and helped Barletta develop a plan to implement this lift. Highlights of our work include the following:

• Calculated approximate stresses in the existing truss members as part of feasibility studies for various pick options

• Developed a rigging arrangement allowing Barletta to lift the truss from pick points at the truss’s top chords, which eliminated the need for a large and expensive longitudinal spreader beam and was significantly more stable than attaching rigging to the bottom of the truss

• Developed conceptual sketches of the rigging and the hoisting operations, including plans showing the crane pick radii

• Analyzed the existing bridge for forces during the hoist and designed lifting components, including new hoist lugs, shackles, slings, and the small transverse spreader beam

• Prepared a package of calculations and sketches to support the lift and submitted it to MBTA for their review

By using our plans, Barletta successfully removed the existing bridge superstructure in approximately three hours.