Interested in this claim, because it sounds about right, except that I can’t name a bridge constructed in the past 50 years.
The bridges we can all name are pushing 100+ right?
The bridges we can all name are pushing 100+ right?
There are now two Tacoma Narrows Bridges. The oldest was built in 1950. The one that infamously collapsed was built in 1940. The newer bridge is from 2007. The West Seattle Bridge was closed due to damage in 2020 and reopened after repairs in 2022. It was originally built in the 1980’s after the previous bridge was hit by a ship. There are two floating bridges on I-90 east of Seattle. One of them sunk during reconstruction work in 1990 and was replaced. Theres also a new 520 floating bridge that opened in 2016. The Hood Canal Bridge (also a floating bridge) originally opened in 1961, sunk in 1979, was reopened in the 1980’s, and large parts of it were replaced in the 00’s.
The Ballard Bridge actually is over a century old! It was opened in 1917. However there was a lot of reconstruction done during the 1930’s. The Fremont Bridge is also from 1917. Both of these bridges span a ship canal that was built between 1911 and 1934. The Aurora Bridge was also built in the 1930’s.
I’d argue the Bayonne Bridge raising kinda counts since it was almost a rebuild and more impressive in many ways since it stayed open the whole time.
Meanwhile in the San Francisco Bay Area they replaced the Bay Bridge…
https://www.nytimes.com/2006/01/17/nyregion/a-bridge-that-ha...
1. Built to last only 50 years to save on materials (as the other commenter noted).
2. Built over literally the widest possible part of the Hudson because the governor got in a pissing contest with the Port Authority and wanted all the tolls to go to the state, which wouldn't have been the case had it been built like 2 miles south where the river is narrower.
3. Designed with zero redundancy, such that a "critical fracture could make the bridge fail completely because its supports couldn’t transfer the structure’s load to other supports." [0]
So yeah if we're being real, 50 years was quite optimistic.
The new Tappan Zee is apparently supposed to last 100 years, though given the incidents with substandard materials being used, as well as ever-increasing traffic, who knows.
That said, driving over a bridge 10 years past its planned EOL and being able to look down directly to the water through gaps in the concrete was always a nice feature though -- who needs coffee when you've got that to get your heart rate up!
[0]: https://en.wikipedia.org/wiki/Tappan_Zee_Bridge_(1955%E2%80%...
Keeping in mind that mid-century Japan and Germany were in ruins and the possibility of nuclear annihilation of urban centers very much at the top of many people minds. 50 years may have seemed an optimistic survival rate of built structures at the time.
Its replacement is a self-anchored suspension bridge.
The original western span, actually a double suspension bridge, remains standing, as constructed in 1933, 91 years ago.
In the DC/MD/VA area, almost all the bridges I can name are less than 100 years old. Woodrow Wilson, American Legion, Chesapeake Bay Bridge, Chesapeake Bay Bridge-Tunnel, Key Bridge, Key Bridge, Nice Bridge, Memorial Bridge, Chain Bridge, 14th street bridges... Some of those were even built after 2000! Also the New River Gorge Bridge in WV is pretty famous and not even 50.
Well, actually, the Key Bridge (in DC) apparently turned 100 years old last year. And I guess the Long Bridge (though not a road bridge) is also over 100...
Here's an interesting list of major bridges with dates, most of the newer ones being replacements: https://www.carolinadesigns.com/obx-guide/fun-info/bridges/
They even note a rare exception designed to last 100 years with maintenance.
They more or less do continuous maintenance during the warmer months of the year.
(So older than 50, but younger than 100)
https://en.wikipedia.org/wiki/Zilwaukee_Bridge
Sticking with the mid-western therme, the Chicago Skyway was built in 1958
The Millau Viaduct also comes to mind when thinking of famous, iconic modern bridges.
https://en.wikipedia.org/wiki/I-35W_Mississippi_River_bridge