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Ed Yeates reporting The State Capitol restoration is mind-boggling considering it has all been done without altering the original architecture of the building. Everything is as it was not only six years ago, but restored, in some cases, to the way it was originally when the building was first built.
What is really amazing about this restoration is that the building itself--including all the decorations, cornices, balconies, and more--has been strengthened and reinforced in ways you'll never see.
You'll notice the obvious, like this meticulous restoration of the glass roof--not on the rotunda floor, but the floor below, where the architect originally had glass panes to let sunlight from two floors above shine through to the floors below. They've been un-covered and restored. Even the incandescent light bulbs that were originally here have been masterfully remanufactured.
But again, what you don't see is equally impressive. The building as a whole has been retrofitted to make it earthquake resistant.
Deep in the bowels only engineers can appreciate, this huge building was literally de-coupled from the ground, but in a way so it never had to be lifted or moved.
Crews have installed 265 base-isolators to hold up the whole state capitol. Each isolator sits on a new footing. On top, new concrete beams--each 5 feet wide and 2 and half feet thick-- now support the original floor of the building.
"They interlock all of the isolators, so not one isolator is going to behave independently. Rather, we have 265 isolators that will all be working in concert, enabling the building to move together as one large lumped mass," explained principal engineer Jerod Johnson, of Reaveley Engineers and Associates.
Before, the Capitol would have shaken violently during an earthquake, shearing pillars and walls. The rotunda could have easily collapsed. But now, there will be very little shaking, with damage so minor the building could be easily re-occupied.
Getting isolators under the 6.6 million-pound rotunda was a feat by itself. In fact, Johnson said, "I don't know of anything that has been done like this."
How complex? A series of new, huge concrete beams wrap around the original four bown piers that support the entire drum and dome. Those concrete beams extend beyond the rotunda footprint, sitting on base isolators that, in turn, sit on new footings.
Retrofitting on floors above? Equally impressive! New strengthening beams and supports are hidden inside original hollow walls and shafts. Glass panes in the sunroof will not fall because hidden seismic clips will hold them in place. Rosettes, trim, cornices, balusters, pedestals and balconies all have new reinforcement, all hidden.
"Below this capstone there was enough space to where we could go in and add reinforcements-- bars and grout and concrete--to stabilize that whole pier so that it does not become a massive projectile in an earthquake. In addition, the balusters have all been dismantled and put back into place with new stainless steel pins," Johnson said.
