Expanding on why this will not be an easy fix...
A few other structures were mentioned that were put back in service "ahead of time"
LA, Philly, and Atlanta? were mentioned.. those are all small simple span bridges..
Access is easy, you can drive right up with 10 wheelers and loaders and start removal of the rubble... Its easy to erect new steel, easy to support the structure while it being built..
This is cribbing and a jacking frame being built so this structure (and approach ramp to the GW bridge) Highbridge in the background.. can be jacked up and the old rocker bearings removed, and new MR bearings installed..
And simply scale.. The span of they Key bridge is, just guessing 3, 500 foot spans to be replaced, and a portion of one of the approaches that was also damaged..
I would imagine they are going to use the remaining approaches to build from..
In these pics are deck panels for the 59th St bridge.. a few months production
Con't