[Updated 8/24/15, see below] The ScienceWriters2015 logo, designed by Brooklyn-based artist Jason Longo, features the Longfellow Bridge, a graceful granite-and-steel structure that has been carrying train, automobile, bike, and pedestrian traffic between Cambridge and Boston since 1908. But conference attendees traveling to Cambridge in October may notice something funny: the signature towers on the bridge's central piers, which earned it the nickname "the Salt and Pepper Bridge," are missing. What's going on?
As it happens, the Massachusetts Department of Transportation is about two-thirds of the way through a three-year*, $255 million project to rehabilitate the once-crumbling bridge. The towers had to be disassembled—after every stone was carefully catalogued—to make way for the gantries being used to bring new elements of the bridge's steel understructure into place, and to allow access to the bridge's hollow piers.
The salt-and-pepper towers will return, freshly scrubbed and cleaned, when the roadway work is done. Amazingly, the bridge will remain open to two-way subway traffic and one-way car traffic throughout the rehabilitation project. It's a little like repairing a jet engine in flight. The process is illustrated in this video produced by MassDOT:
On a separate note: sharp observers may notice the cables at either end of the Longfellow Bridge in our logo. That's a figurative reference to the Leonard B. Zakim Bunker Hill Memorial Bridge, about a mile downstream from the Longfellow Bridge. For better or worse, the Zakim Bridge has displaced the Longfellow as Boston's most iconic bridge, mostly because of its elegant cable-stayed design, which is lit up in various colors at night. Trivia fact: the Zakim is the widest (though not the longest) cable-stayed suspension bridge in the world.
*Update, 8/24/15: The Boston Globe reported recently that the Longfellow Bridge restoration project will take two years longer than originally planned, stretching into 2018 "because of complications associated with preserving the historic nature of the century-old structure." One problem: engineers had to re-learn the abandoned art of hot riveting.