Delaware Memorial Bridge Pin and Link Rehabilitation and Miscellaneous Steel Repairs, First and Second Structures

American Bridge was the general contractor for the pin and link rehabilitation of both Delaware Memorial Suspension Bridges. The twin suspension bridges span the Delaware River carrying Interstate 295 between Delaware and New Jersey. The eastbound span is 10,765 feet long while the westbound is 10,796 feet with both bridges being very similar in appearance.

AB performed the following scopes of work:

• Suspender rope replacement: AB replaced 32 suspender ropes at 16 tower locations. To complete this, AB installed temporary bracing at neighboring ropes, replaced the internal suspender steel bearing, and installed jacking brackets and thread rods at 16 points. In addition, AB designed and installed a bracing and jacking system for the ropes that were being replaced.
• Temporary truss support: AB’s in-house engineering designed temporary steel jacking frames installed at the 16 tower locations to support pin and link removal operations.
• Internal diaphragm installation: AB installed angle and plate diaphragms in 64 internal tower cells for stiffening to accommodate new bearing brackets. Installation involved rivet removal and drilling of new holes through several steel plies to tie into existing framing and new construction.
• Bearing bracket installation: AB installed 16 steel plate and angle brackets as exterior connections to towers to support the new uplift bearings.
• Removal of existing pin and link assemblies: AB’s in-house engineering designed a temporary support to transfer the bridge load. AB then designed and fabricated custom pin pullers to remove 32 large diameter pins and 16 link assemblies. Removal was completed with only non-destructive methods so that the material could be retained by the owner.
• Wind restraint repairs: AB replaced the steel gusset plates, bronze bumper plates, and steel pin and blocks at eight tower locations. AB designed and fabricated the temporary jacking and bracing system required to stabilize the truss during the repair period.
• Bearing access platform installation: AB installed 16 new access platforms with handrails and grating.
• Girder floorbeam tie plate repairs: AB replaced seven tie plates along the approach girder spans. AB’s in-house engineering designed and fabricated the temporary jacking system required to stabilize the spans during replacement.
• Girder web and truss floorbeam crack repairs: AB used dye penetrant to locate the extent of cracks and drilled relief holes to stop the spread.
• Girder floorbeam tie plate repairs: AB replaced seven tie plates along the approach girder spans. AB’s in-house engineering designed and fabricated the temporary jacking system required to stabilize the spans during replacement.
• Truss floorbeam bracket repairs: AB designed and fabricated a jacking system to support the bridge loads during construction along with custom access platforms. Due to extreme deterioration in the existing steel, AB worked with design engineers to create a new repair detail, changing from a bolted connection to a welded connection, with pieces required to be modified and drilled in place.
• Tower floorbreak stringer repairs: During the rehabilitation, AB discovered the bridges had deterioration of the finger joint support beams which prohibited repair as described in the contract plans. To remedy this, AB designed alternative repairs to replace custom bearing plates, with a bolted assembly, which were installed at eight locations.