Engineering the BART System

August 27, 2015 1:04 AM

Engineering Geology of the Bay Area Rapid Transit (BART) System, 1964-75 (J. David Rogers & Ralph B. Peck, published 2000) chronicles the construction of the subterranean components of BART.
posted by DrAmerica (17 comments total)

Wow, this has "Djeo Read This" written all over it in big neon letters. I work in the telecom industry now but I studied geology in college. I fly out to San Francisco this coming Saturday morning. It's like a twofer!

Thanks DrAmerica!
posted by djeo at 5:33 AM on August 27, 2015 [1 favorite]

"The tunnels were dug from a shaft excavated near the intersection of Randall Street and San Jose Avenue". That's the shaft that should be the 30th street BART entrance.
posted by Nelson at 6:34 AM on August 27, 2015 [5 favorites]

I am extremely happy that you posted this.
posted by sandettie light vessel automatic at 6:55 AM on August 27, 2015 [2 favorites]

I didn't realize that 100,000 years ago during the Sangamon interglacial, sea levels were 22 feet higher and the East Bay flats from Hayward to at least downtown Oakland were under San Francisco Bay. Apparently this was learned from mud excavated during the construction of the Hayward BART station. Reminds me of this page of fossils found while digging the Caldecott Tunnel through the East Bay hills. Camels! Sabertooths! Filamentous algal strands!
posted by drdanger at 7:01 AM on August 27, 2015 [2 favorites]

This is getting shared with everyone in my Bay Area transit engineering department. Thanks!
posted by Captain Chesapeake at 7:02 AM on August 27, 2015 [2 favorites]

Out in Moraga (behind the Oakland hills) in Bolinger Canyon you can clearly see that the rock was once sea bed, very cool, glad it's dry for now though.
posted by zeoslap at 8:17 AM on August 27, 2015 [1 favorite]

Needs BayAreaRapidTransit tag. Great post thanks for sharing.
posted by joseph conrad is fully awesome at 9:29 AM on August 27, 2015

"The tunnels were dug from a shaft excavated near the intersection of Randall Street and San Jose Avenue". That's the shaft that should be the 30th street BART entrance.

As someone who lives just a couple blocks from this intersection, I concur.

I've also never heard the area called "Fairmont Hills." Is this a thing around here?
posted by late afternoon dreaming hotel at 12:07 PM on August 27, 2015

I've also never heard the area called "Fairmont Hills."

Me neither, and a quick Googling suggests this term is idiosyncratic to this article. I asked my partner who lived in SF in this era, he's never heard the term either. It's not even particularly hilly there by SF standards, although it's certainly not flat. The route roughly parallels the Bernal Cut but is just a bit north (and well under) it. I wonder if Metafilter's own Eric Fischer knows the term "Fairmont Hills"?
posted by Nelson at 12:25 PM on August 27, 2015

Fairmount Heights is a common name for the hilly area northwest of the Bernal Cut between Noe Valley and Glen Park, so that's probably what they're referring to. The 1961 plan that was going to tunnel straight from Civic Center to Balboa Park called its tunnel the "San Miguel Tunnel" instead.
posted by enf at 12:32 PM on August 27, 2015 [1 favorite]

Thanks Eric! I missed it because of the variant spelling. FoundSF has a good article about Fairmount Heights.
posted by Nelson at 12:38 PM on August 27, 2015

Does anyone have Figure 8: Transverse cross sections through the Embarcadero Station? Can anyone imagine what "unfortunate typographical mistake"/"typographical misadventure" would prevent its publication?
posted by creade at 2:38 PM on August 27, 2015

I've always been skeptical of a 30th street station. Seems like it would be awfully disruptive and expensive for not a whole lot in return. I'd rather see Bart on Geary street.
posted by DrAmerica at 6:42 PM on August 27, 2015

DrAmerica, BART already runs under 30th and Mission, and has a shaft ready-dug for it. To make a spur line out under Geary's waterlogged sand would be an engineering project even more ambitious and messy than the original 1960s dig under Market Street. I'm not saying rail on Geary isn't sorely needed, but the 30th and Mission station would have a ready-made catchment area of people too tired to head down to 24th. Easy money!

I used to live around that area, in what was jokingly called "Bernal Depths" by folks who identified more with the Mission side than the Church side. Just getting across Cesar Chavez was enough of a tiresome wade through terrible pedestrian infrastructure to make you give up and try something else. And don't get me started on the bus routes through there.

London may still be in remedial classes on bicycle/pedestrian infrastructure, but it's decades ahead of the US and the Underground is amazing.
posted by rum-soaked space hobo at 7:14 PM on August 27, 2015 [1 favorite]

I'm fascinated by public infrastructure, and sometimes I wonder if I should've been a civil engineer, like my father. But even when he worked for CalTrans back in the day, all he was doing was expanding freeways or whatnot and eventually he went in a different direction. I know it wasn't easy to get BART built, but it seems like getting infrastructure done these days is a real struggle.
posted by Standard Orange at 11:13 PM on August 27, 2015

Yes, I am familiar with Bart's routes, what I mean is that I don't think the area around 30th and mission would have enough people using Bart that otherwise wouldn't because either Glen Park or 24th is too far away. If it can be built without destroying any businesses or houses then I'm all for it (maybe get rid of the Shell station? I could live with that). But I just don't see where the money would come from, realistically.
posted by DrAmerica at 1:06 AM on August 28, 2015

If any engineers are reading this and feel so inclined, I would greatly appreciate it if someone could explain "negative skin friction" to me, as described in this paragraph:

Although the length of most piles left above the tunnel linings was only 4 to 6 feet, the resident engineer was concerned about negative skin friction (downdrag) pulling these piles down onto the thin steel membrane of the tube's flexible linings. Though engineers doubted downdrag could be developed in such short piles, it soon did, and the lining developed a series of obvious dimples. The contractor had to weld plates and fashion makeshift stiffeners to keep the dimples from preceding further.

posted by DrAmerica at 3:51 PM on August 28, 2015