Starting last weekend (June 3-6), MassDOT is replacing one bridge every weekend on I-93 in Medford MA. Using prefab concrete pieces, each bridge is going from demolition to new, fully functioning bridge in 55 hours...10PM Friday to 5AM Monday. All 14 such bridges will be done this summer and the work will be done every weekend except for the one immediately preceeding July 4th. The bridges, most of which are originals (built in 1959), were literally falling apart, but the new ones are expected to last 75 years.
The first one (over Riverside Avenue) was done and back in service on time. The ones being done this weekend (over the MA-60 rotary) are being done in rainy weather, so we'll see if/how that slows things down.
They're keeping the road open, but have installed a zipper lane to shuttle (for the first seven bridges on the northbound side) northbound traffic onto the southbound side through Medford.
MassDOT has an informational web site, revised every week to show the project's progress and detail which work is next up and how to get around it.
http://www.93fast14.com
That is quite impressive. Of course, we're not replacing any abutments or piers in the process.
I noticed some BGSes during the concrete pumping portion of the video, and decided to see if they were the actual BGSes on I-93. Google Street View (http://maps.google.com/maps?ie=UTF8&ll=42.416577,-71.103879&spn=0,0.002642&t=h&z=19&layer=c&cbll=42.416577,-71.103879&panoid=i0slgWMCDjfyEATF6O9ISQ&cbp=12,18.23,,0,-6.58) shows that they are correct.
Also, while I was looking for the BGSes on Street View, I noticed that the video even shows the concrete pavement patches in the locations they are on the actual bridge!