Under the heading of learning something new every day, one of the most iconic structures on our Georgia coast, the Talmadge Memorial Bridge in Savannah, connecting Georgia to South Carolina across the Savannah River is not a suspension bridge.
Suspension bridges like the Golden Gate, Brooklyn Bridge, or famed London Bridge, have large cables connected to massive load-bearing anchors at each end, as well as frequent piers underneath (anchored to the channel, river, or even ocean floor) or along the bridge span to assist with load bearing.
The Talmadge Bridge is a cable-stayed bridge, with the high-tension cables supporting the roadway by pulling the bridge up, versus via support and tension from underneath.
Opened in 1991, the Talmadge Bridge is no longer quite high enough for the world’s largest container ships to always make it underneath and into the Ports of Savannah, even at low tide and following the multi-year, multi-million deepening of the Savannah shipping channel.
The Port of Savannah’s container-ship market share for all of North America is roughly 11%, making it a leading port along the East Coast in tonnage and contributing an estimated $59 billion each year to Georgia’s GDP as well as the direct and indirect employment of about 561,000 Georgians. Current traffic loads at the port make it the third busiest in North America.
Though the lead time on building that next generation of cargo tankers is long, the current largest, when fully loaded, needs about 20 more feet of clearance, or what is known as “air draft” in the bridge and shipping industries, to cross under the Talmadge Bridge safely.
To do this, the Georgia Department of Transportation (GDOT), along with Kiewit Infrastructure South, an engineering design firm based in Peachtree City, is going to attempt something never previously endeavored. They plan to lift the highest portion of the 1,100-foot span of the Talmadge Bridge 20 feet higher.
They will do this by replacing the bridge’s high-tension support cables with new, shorter cables, at an estimated cost of $189 million.
This work is scheduled to begin in 2025 and is projected to be completed by 2028. The project will not raise the entire bridge span but will in effect give the bridge a peak and a good bit more curvature, as well as increase the angle and elevation of the climb.
Current grades and incline on the Talmadge Bridge are at 5.5%, already placing it among the 10 steepest bridges in America.
Those making their first time drive or ride across the bridge often admit this can be a slightly intimidating trip. If successful in adding to that curvature, parts of that incline will reportedly be closer to a 7% grade.
Kiewit has previously replaced cables on other cable-stay bridges, including the first span to undergo such maintenance, the Hale Boggs Bridge which spans the Mississippi River in Louisiana. That project was completed in 2012; however, this will be the first cable-stay bridge replacement with purposefully shorter cables, to reshape and raise the bridge and increase its air draft.
Eventually, though, the next generation of cargo ships, already in the planning stages, will require an entirely new bridge, at an estimated peak height of 230 feet above sea level, or a tunnel bored more than 100 feet below the seabed, to allow for passage of those new mega-cargo container ships, as well as the next generation of luxury cruise liners that can make the Titanic look like a slightly over-sized dingy.
Either of those two options comes at a hefty price tag in the $1-2 billion range at current estimates.
Thankfully, the shipping industry still gives long lifetimes to most of its sea-worthy vessels, and the next generation of ships are generally not constructed until they have already been financed.
It’s somewhat ironic that the last of America’s original 13 colonies, and within the line of sight of GeneralJames Edward Oglethorpe’s originally planned colony of Savannah, will be the home of a newly designed and reconfigured bridge rising even higher as it spans north to the Palmetto State.
I will keep in mind there are a couple of other routes to St. Simons, Jekyll Island, and other points south, staying a bit inland, rather than along I-95, and at least until those new shorter cable spans are fully in place, I will remain a bit in suspense to see if engineers can teach a slightly old bridge some new tricks.