Oakland Geology

A few weeks ago I set foot inside our City Hall—for the first time, I’m embarrassed to say. I hope you will step inside before you’ve lived here 25 years, like me. I’ve always known we have a gorgeous building, and now I’m amazed. C’mon in.

First we’ll have a look at the structure’s famous seismic retrofit. See the light-colored strip at the foot of the walls? That’s a steel apron that covers an air gap all the way around the building. That gives the structure room to shimmy and sway on its fancy rubber feet during a severe earthquake. You can see it better by the side door, on 14th Street.

Notice the bellows-style barrier on the building below the street level, filling that air gap.

When you go inside there’s a little exhibit space that has, among other interesting objects, this cutaway model of the base-isolation pads.

There are more than a hundred of these under the building, each one the size of a cafe table, made of thick rubber and lead plates. In the early 1990s, when City Hall was retrofitted, no one had ever used this technology at such a scale before. Since then many other precious historic buildings have used it. Hearst Mining Hall on the UC Berkeley campus is one.

OK, now comes the luscious stuff. The interior is beautiful in the way people favored a hundred years ago. Here’s the grand stairway leading from the front door up to the City Council chambers.

Click the image for a large version. The balustrade is translucent marble on top, ceramic tiles on the sides. The stairs are marble. The ornamentation on the walls is plaster.

Here’s a skylight on the upper floor, edged in black marble.

And this thing is a large lighting fixture that illuminates the rotunda. Click that photo for a large version. It was futuristic in 1914, and it’s still futuristic today.

There are other, smaller fixtures elsewhere on the ceiling that are worth searching for. The bronze ring suspended above the big ball depicts personifications of the planets—eight of them, from Mercury to Neptune, just like today.

This entry was posted on 24 November 2014 at 9:42 pm and is filed under Oakland stone. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.