Not even the amazing speed of this winter’s construction can top a flying dinosaur, but the last few months have been a period of exciting progress on the Expansion Wing.

As the building’s skeleton has emerged up and out (and out and out) of the basement, the project site literally looks different every day. For a beautiful illustration of that fact, check out this time lapse video of construction; it covers the period from April 2010 to the beginning of Feb. 2011 at 10 hours per second:

Here are just a few of the big things the construction team has accomplished since November:

• The concrete structure for the basement, level one, level two, and level three is in place and curing (getting up to strength.) Once the formwork is removed, temporary wooden shoring columns remain in place as the subsequent floor slabs are poured. This allows the contractor to keep building the structure even as the concrete below does its final bit of drying out.

• The scaffolding and formwork for the slab on level 4 are being installed, and the columns that will support the wing’s highest floor are being formed and poured as well. To prepare for a slab pour, the contractor installs a system of scaffolding, plywood, steel and aluminum beams and supports, and metal pans to serve as a giant jello mold for the concrete to fill. Woven in between the pans and the plywood are the steel rebar and cables that reinforce the slab’s concrete and also allow the slab to get “tied in” to the columns above and below it.

• Post-tensioned steel cables within the concrete structure are beginning to be stressed on the third level. Post-tensioned steel cables are a way of reinforcing the structure. They serve the same purpose that rebar does, but what happens is that they pour the concrete over the cables, then after the concrete has dried for a few days, the contractor pulls on the cables from both ends with hydraulic jacks. (This is called stressing.) The tightening of the cables is part of strengthening the slab. Using post-tensioning is one way to get longer spans of concrete between columns without having to make the floor slab thicker, meaning the diplodocus will have plenty of room to stretch his neck in the new Paleontology Hall.

• The new loading dock, which extended the existing dock, was poured at the end of December. While museum visitors rarely see it, the loading dock is one of HMNS’s critical areas of operations.  The artifacts and construction materials for every exhibit flow through the dock. The delightful creepy crawly animals that the Education department takes to visit schools depart from the dock. And the tables and chairs and scrumptious food for special events arrive at (and are sometimes even prepared at) the dock. Not only does the new dock provide more space for these important functions, but it also includes a new powered lift to allow for more flexibility when heavy crates with fossils or mummies arrive. Kudos to the contractor for doing this work with minimal disruption to museum operations!

• The new natural gas emergency backup generator was delivered and set in place. It’s not the sexiest piece of equipment on the job, but when you need it, you’re glad it’s there… especially if you’re a fish or a butterfly.

All that in just three months? You betcha. And the fun has only just begun!

PS. We’ve added 25 new images of the site to our HMNS Expansion Flickr set – including the first photos from inside the new building!