Crews build out quick platforms to perform work, utilizing a Grove 8100 crane for material handling and JLG 1300 boom lifts for access.
(Aetna Bridge photo)
Built in the 1940s, the northbound span of the Goldstar Memorial Bridge continues carrying five lanes of I-95 traffic safely across the Thames River from New London to Groton in Connecticut.
Although inspectors have declared the bridge to be safe, the Connecticut Department of Transportation (CTDOT) has decided to keep it safe well into the future by commissioning a project to strengthen the northbound bridge.
The job will have three phases, totaling approximately $407 million, with the entire project due to be completed in 2029. The phases include rehabbing the truss spans, work on the approach span, fixing bearings, concrete repairs, improved drainage systems, and finally a full deck replacement.
The box truss bridge, the largest bridge in the state, is just more than a mile long and carries approximately 60,000 vehicles daily. The bridge also passes over railroads and local roads, making it a key transportation artery in the state.
Scott Thompson is the project manager of Aetna Bridge, who was awarded the contract for Phase 1, and supervises a team of approximately 70 workers for the current phase of the project. The job is not for the faint of heart as the workers do their jobs on a bridge that soars 110-150 ft. above the water at the midpoint of the bridge. The upper platform is 140 ft. above the water.
The bridge was bult with silicon steel, at the time a best-of-its-kind alloy, but now known to become brittle.
"We will be strengthening the structure to meet current standards," said Thompson. "We will be removing 7/8-inch rivets and replacing them with 1-inch high-strength, galvanized bolts. We will also be adding strengthening plates at key points on the bridge trusses. In all, we will be putting 1.4 million pounds of steel into the bridge."
Thompson estimates that the bridge was last given a full paint job 50 years ago. He understands that the coating system being applied will provide rust protection for an additional 50 years.
The strengthening plates vary in size from 1 ton to 200 lbs. Aetna team members work closely with the painting team. After Aetna's team supplies the new bolts and plates, the painting contractor paints the newly finished area.
Aetna Bridge's activity required the company to build specialized work platforms to support the heavy lifting needed to hoist the metal into place for installation by the workers. The team used rough-terrain cranes and rough-terrain forklifts to wrestle the material into place. From that point, workers used electric chainfalls for moving steel into place for final bolting onto the trusses. The team made extensive use of other heavy-duty equipment such as mag drills, rivet busters and impact guns.
Working over the Thames River means that workers are paying careful attention to environmental issues.
"We are using water soluble and biodegradable cutting oils for all of our metal machining," said Thompson. "We are also trying to minimize our use of throw-away plastics. In addition, we have engineered environmental protections into our processes to protect the river from our construction operations."
Aetna Bridge has placed considerable emphasis on worker safety for the project, including project safety officers and requiring safety officers for subcontractors. The safety team is using a CTDOT-sponsored plan to control motorists driving under the bridge. A safety boat patrols the water under the bridge when construction activity is under way above. Boaters are being alerted about the activity.
"One of the biggest challenges for the job has been the aggressive schedule for our work on the bridge," said Thompson. "We were given very strict criteria for our work and the engineering we had to do. There was very little give in our schedule especially since we are the first phase of the project with others following closely after our part."
Another unexpected wrinkle in the schedule was the directive to avoid disturbing the nest of a peregrine falcon who made its home on the adjacent bridge.
"Ours is a painting and steel project, so this restriction was an enormous reduction in the time we could be working on the bridge."
Thompson estimates that the work on the first phase of the project is 50 percent finished. He believes that when the project is completed it will have a sizeable impact on traffic in the state.
"This project will enable oversized vehicles and permitted trucks to now use the Goldstar Memorial Bridge. Before this they had to use a 17-mile detour. The work will increase the strength of the bridge and remove a restriction on a major artery for northbound traffic in Connecticut." CEG
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