Skanska USA Civil photo
Cranes are used to install the temporary work and drill platforms that will be used to install the new bridge foundations and steel towers.
The article below originally appeared in and is posted with permission from:
https://www.constructionequipmentguide.com
Transportation historians estimate that trains have been crossing a bridge over the Hudson River between Albany and Rensselaer in upstate New York for nearly 150 years. The original railroad bridge was built in 1866 and replaced in 1902. Constructed as a swing bridge, a portion of the structure rotates to allow river traffic to pass.
Skanska USA Civil photo
The bridge is owned by CSX and operated by Amtrak. Train traffic slows considerably when it passes over the old bridge. Over the years, it has required extensive, costly repairs.
The New York State Department of Transportation (NYSDOT) has contracted with Skanska Koch LAB JV (SKJV), a design-build team consisting of Skanska USA Civil and Skanska Koch, with HNTB as its designer, to design and build a new lift bridge for $635 million. The new structure will have two tracks and will accommodate both freight and Amtrak traffic simultaneously as well as a shared use path for pedestrians that connects the Albany Skyway and the Empire State Trail with the Rensselaer Waterfront Esplanade. The bridge currently handles 12-15 trains per day.
Building a bridge over the Hudson has many challenges. One challenge is a moratorium on working in the Hudson River between March 1 and October 1. The builder is required not to disturb sediment at that time because of the spawning Atlantic sturgeon, which is considered an endangered species. Another challenge is marine access to the work. Building by traditional methods would require workers and equipment to operate from barges and from a bridge deck approximately 60 ft. over the river.
Instead, Skanska decided to use a method that would be safer, faster and cheaper. Using its experience gained from the construction of the Portal North Bridge, company planners decided to assemble the truss sections of the bridge on land at Port of Coeymans Marine Terminal in Ravena, N.Y. The completed truss sections will be floated by barge approximately 10 mi. upriver before being set in place on the new foundations using the tide and hydraulic jacks. By building on land, the team will save approximately 12 months of construction time.
Paul Olson, project executive of Skanska USA Civil, will lead the construction.
"We are building a new bridge that will accommodate train travel for the 21st Century," said Olson. "The new bridge will not only provide for more efficient train service, but it also will provide a link, via a shared use path, between the Albany and Rensselaer waterfronts for the surrounding communities."
Working closely with NYSDOT during the procurement process Skanska was able to optimize span lengths resulting in a reduction of the number of in water piers from eight to six resulting in a reduced impact to the river. Rather than building large cofferdams that would require a large footprint within the river, the Skanska team will install 6-ft. diameter caissons within oversized casings into the river bottom that will allow the work to proceed with minimal impact to the surrounding habitat. These caissons have an average depth of 70 ft. The bridge will consist of three truss sections, two lift towers and four girder spans.
Skanska USA Civil photo
To maintain the required rail alignment, the new bridge is being constructed within 15 ft. of the existing bridge, with the stairs of the towers for the new bridge touching the old bridge. At the latest stage of construction, the old bridge will no longer be able to open while the last section of the new bridge structure is floated into place. Workers will then have only 58 hours to complete the new bridge and switch rail traffic over to the new structure.
At that time, construction teams will begin demolishing the old bridge and recycle it.
Skanska is currently 20 percent complete with the project, building new track beds to support the transfer of train traffic from the old bridge to the new, installing foundations for the new abutments, installing temporary work platforms in the river needed to install the new bridge piers and fabricating the steel for the three truss sections. Through close collaboration between NYSDOT, Amtrak, Skanska and HNTB, including weekly design meetings with all project stakeholders, the team has progressed the design to allow the above-mentioned construction work to proceed. Currently, the final design of the critical bridge structures is substantially complete with the remaining design units at the final stage of design coordination with NYSDOT and Amtrak.
During 2025, construction teams plan to complete the temporary work platforms, temporary piers and trestles. They will start the foundation work.
By the end of 2026, teams will have the concrete bridge piers largely completed and begin installing the towers and counterweights for the lift truss.
During 2027, the trusses will be completed and floated upriver to be lifted into place.
Skanska USA Civil photo
Due to the aggressive project schedule, the Skanska team is required to work throughout the winter months. This requires the design of all temporary work platforms to account for ice flow on the river. Under the harshest conditions, Skanska will employ ice breakers to break the ice to provide access to the work areas on the river.
The project will require approximately 14,000 cu. yds. of concrete and 15 million lbs. of steel.
Workers will run an abundance of cranes, including several Liebherr LR 1300 crawler cranes, with a maximum lifting capacity of 330 tons. These cranes will stay on location for nearly the entire length of the project to support both the installation of the foundations, concrete bridge piers, and the superstructure steel.
Two Liebherr LR 1300 cranes will be used, along with vibratory and impact hammers to install the temporary work platforms.
A KOBELCO SK520LC-11 excavator is being used for excavating soil and rock around the bridge and support foundations.
Workers will use traditional JLG boom lifts for access to heights for both the land based and water-based work. Workers will follow safety regulations for fall protection when work over the river is required.
"We will be building precast structures off site, then floating them upriver and installing them over the caissons," said Olson. "Additional concrete pours will be done at that time, eliminating the need to install traditional formwork over the river."
Lifting a Bridge
Skanska also will install the machinery and control systems required to raise the approximately 4,000,000-lb. lift span to allow barges, pleasure craft and occasional river cruise vessels to pass safely under the bridge. These systems consist of many different components including 100 hp motors, brakes, mechanical reducers, hundreds of feet of shafts and a control system consisting of thousands of electrical connections.
Workers will use a barge-mounted crane for the riskiest picks of the job — two sheaves, 15 ft. in diameter, for each of the two towers. The sheaves will be used to guide the cables and will balance the movable span with the massive counterweights that will allow the bridge to move and let boats to glide beneath the bridge.
As the bridge is completed, Skanska workers will plan to restore some of the wooded area on the Rensselaer side of the bridge and improve the connection to the Mohawk Hudson Bike Hike Trail. This mixed-use path will benefit cyclists and walkers. It is a key part of the Empire State Trail, which extends for approximately 750 mi.
"We want to leave the environment better than how we found it," said Olson.
When the project is finished, it will have a positive impact on the area.
"Amtrak and CSX will be able to run more trains and run them at normal speed," said Olson. "It will reduce travel time for the public and for freight shipments. We will also give residents convenient access to the river and to the local environment." CEG
(All photos courtesy of Skanska USA Civil.)
