Skanska Builds a Lifting System into the George Washington Bridge
30-Second Takeaway
Skanska designed a custom hoist system to replace 592 suspender ropes and install 74 work platforms along the main cables of the George Washington Bridge. Working as high as 320 feet above live traffic and the Hudson River, crews needed a lifting method that did not depend on conventional cranes reaching over the bridge. Hoists built by Allied Power Products were staged inside the main towers and routed through sheaves to lifting points along the cables. Two synchronized hoists could lift up to 40,000 pounds together. The bridge rehabilitation is being carried out under a US$452 million contract with the Port Authority of New York and New Jersey.
Bridge Infrastructure Becomes the Lifting System
Replacing the bridge’s original suspender ropes and rehabilitating its main cables presented a difficult access and lifting challenge. Conventional cranes could not practically reach the work areas high along the cables while the bridge continued to carry traffic.
Skanska and Allied Power Products developed a custom hoist arrangement using the bridge itself as the lifting structure. The machinery was staged inside the main towers, protected from the elements and positioned to lift loads to specific points along the cables.
Each hoist line exits a tower at roadway level, travels up through sheaves to the top of the tower, then runs through additional sheaves along the main cable. From a further sheave, the line drops back toward the roadway to pick up its load. The system can operate with a single hoist for smaller lifts or with two synchronized hoists, providing a combined capacity of up to 40,000 pounds.
“In effect, the bridge became its own lifting structure,”
Skanska said.
“The machinery stayed protected inside the tower, the lift point could be placed exactly where it was needed along the cable, and no crane had to reach out over traffic or the river.”
Synchronized Hoists Lift Cable Platforms
The system’s synchronized lifting capability was central to installing the work platforms. Skanska designed 74 platforms, each measuring 20 by 60 feet and weighing 40,000 pounds. Their combined weight added nearly 3 million pounds to the main cables, equivalent to about 1,480 tons.
Each platform arrived in four sections. A 50-tonne crane set the sections onto stands beneath the cable so crews could bolt them together. The team then connected a reeved hoist line to each end of the platform. Initially operating the hoists independently, crews raised the platform level and adjusted its pitch to match the cable’s slope. They then switched to synchronized operation to lift it into position.
Skanska compared the total platform weight carried by the cables to 37 fully loaded 80,000-pound tractor-trailers. The installation required careful load control: any imbalance between the hoists could shift more of the load to one side.
Suspender Ropes Replaced from a Closed Lane
The rope exchange took place from a single closed lane while traffic continued alongside the work zone. Crews lowered the old suspender ropes, some weighing up to 9,000 pounds, directly into a dump-style trailer.
New ropes were pulled from a large spool on a low trailer in the same lane and lifted over the main cable. They could be delivered by standard truck during the day, without oversize permits or overnight transport, while the bridge remained open.
Each crane pick from the roadway was planned around lane closures, traffic control and swing radius. A 15-tonne crane worked daily from a closed lane to install galvanized sidewalk railings and carry out service picks.
The heaviest crane lifts went to a Liebherr LTM 1220, which positioned the hoisting platforms inside the main towers. To centre each platform within a tower, crews bolted eight tonnes of counterweight to one side, deliberately shifting its centre of gravity so it would hang and orient correctly.
All lifting took place in daylight, with a maximum wind speed of 25 mph. Vergona Crane and Bay Crane supplied the larger cranes.
Rehabilitation Work Continues Through 2030
Skanska’s contract with the Port Authority of New York and New Jersey covers replacement of all the original suspender ropes, rehabilitation of the main cables, installation of cable dehumidification systems and replacement of the main span sidewalks and upper-level railings.
The bridge’s South Walk pedestrian path reopened on 15 October. The full rehabilitation scope is expected to continue through 2030.
About Skanska
Skanska is a construction and project development company headquartered in Sweden, with operations across selected markets in the Nordics, Europe and the United States. Its U.S. operations include building construction, civil infrastructure and commercial development. On the George Washington Bridge project, Skanska is carrying out a major rehabilitation programme involving the suspender ropes, main cables, dehumidification systems, sidewalks and railings.
Website: https://www.skanska.com/us/en/
About Allied Power Products
Allied Power Products is an Oregon-based supplier and manufacturer of winches, hoists and custom lifting systems. The company designs and builds equipment for applications in sectors including construction, marine and industrial operations. For the George Washington Bridge work, it built the custom hoist system that routes lifting lines through the bridge towers and along the main cables.
Website: https://alliedpower.com/
About the Port Authority of New York and New Jersey
The Port Authority of New York and New Jersey operates and maintains the George Washington Bridge, a major crossing linking Manhattan with New Jersey. Its bridges and tunnels connect the two states and support regional passenger and freight movement. The agency is funding the bridge rehabilitation under its US$452 million contract with Skanska.
Frequently Asked Questions
What is being replaced on the George Washington Bridge?
The rehabilitation includes replacement of all 592 original suspender ropes, along with work to rehabilitate the main cables, install cable dehumidification systems and replace the main span sidewalks and upper-level railings.
How did Skanska lift equipment to the bridge’s main cables?
A custom hoist system built by Allied Power Products was staged inside the main towers. Hoist lines run through sheaves up the towers and along the main cables, allowing crews to lift equipment at selected points without using cranes over the river or traffic.
What is the hoist system’s combined capacity?
The system can lift with one hoist for smaller picks or use two synchronized hoists with a combined capacity of up to 40,000 pounds.
How heavy were the work platforms?
Each of the 74 platforms measured 20 by 60 feet and weighed 40,000 pounds. Together, they placed nearly 3 million pounds on the main cables.
How were the platforms lifted into position?
Each platform was assembled from four sections. A 50-tonne crane set the sections on stands below the cables for bolting. Crews then used two hoist lines, first operating them independently to level and align the platform, then lifting it in synchronized mode.
Did the rehabilitation require closing the bridge?
The rope replacement work took place from a single closed lane while traffic moved alongside. The supplied project information says the bridge remained open during the rope deliveries and work.
