Sturdy Gertie is the second Tacoma Narrows Bridge that opened in October 1950. It was built in same location when Galloping Gertie was using the existing anchors and caissons from the short lived bridge.
The toll plaza was reused to collect the tolls until 1965.
While the insurance from the fall of Galloping Gertie covered 1/2 of the replacement costs, the new bridge was created to make a four lane bridge (Galloping Gertie was two lanes).
Better steel, venting in the roadbed and open railing on the bridges sides, support structure underneath the roadbed, and support from the towers to the support structure prevented the bridge from having movement and twisting as it's predecessor. It can vibrate though when walking on it's surface.
These photos show the underside of the bridge, and the supports on the Peninsula side that were from Galloping Gertie, modified for a 4 lane roadbed.
The plans for expansion
When the Galloping Gertie collapse was reaching it's 50 anniversary's, attention was spent on how to increase the capacity over this part of the sound that needed to handle more traffic as the area was growing.
The option presented was to add four more lanes above the existing bridge, reversible traffic lanes, adding ferry services, or building another bridge (next to the existing one).
Because Study Gertie was built on the supports of Galloping Gertie, there was no way to support additional weight. While ferry service would be temporary, using the existing approach at Titlow Beach would be difficult to use due to train traffic. A new bridge was the solution.
Funding was difficult to get the bridge constructed. Since a major suspension bridge wasn't built in the United States since 1964, designers and engineers were hired from other parts of the world.