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The Boring Company's LA test tunnel is almost complete
Today, Elon Musk announced via Twitter that the first Boring Company test tunnel under Los Angeles is almost finished. When it's complete, the system will be able to carry pedestrians, cyclists and private vehicles at speeds of 155 mph. People will be able to try the loop out for free at a special event at SpaceX headquarters in Hawthorne, CA, on December 10th.
Also at LA Times, The Verge, and The Washington Post.
Previously: Elon Musk's Boring Tunnel Near Los Angeles
Elon Musk pitches $1, 150 MPH "Loop" Rides under Los Angeles
Related: Washington, D.C. Granted Elon Musk's Boring Company an Excavation Permit for Possible Hyperloop
Elon Musk's Boring Company Wins Chicago O'Hare International Airport Transportation Contract
Elon Musk's Boring Bricks
(Score: 4, Informative) by MichaelDavidCrawford on Tuesday October 23 2018, @04:28PM (4 children)
But not the double-decker freeway that ran right next to it. A total of I think 65 people died in the Loma Prieta quake, all but a few of whom were on the lower deck. When I mention this now I am unable to escape the memory that one lady's life was saved when the first responders cut both her legs off with a power saw, and without anesthesia.
There are some tall buildings in Oakland, and there are lots of very tall buildings in San Francisco that were not damaged in any way by that quake.
One reason they weren't is that those buildings were specifically designed to survive earthquakes.
Many of the houses that were destroyed were built during the Great Depression when it was common to use beach sand in concrete. You don't want to do that because beach sand grains are worn smooth. If you make your concrete's sand by crushing up a big rock in a ball mill, its grains will have lots of nooks and crannies for the Portland Cement to adhere to;
Yes I Have No Bananas. [gofundme.com]
(Score: 4, Informative) by Runaway1956 on Tuesday October 23 2018, @04:49PM (1 child)
I don't know about sand wearing smooth. You may be right, you may be wrong. But, oceanfront beach sand contains sea salt. Salt is corrosive. During WW2, the Seabees built a lot of stuff in the Pacific, using beach sand in their concrete and mortar. They fully expected stuff to fall apart prematurely - and most of it did exactly that. There are ways to get around corrosion, but most of this wasn't in use during the world war era, not to mention that it would have been prohibitively expensive.
http://www.claisse.info/2013%20papers/data/e172.pdf [claisse.info]
(Score: 0) by Anonymous Coward on Friday October 26 2018, @09:55PM
I talked to a Lebanese man a few years back. Where he lives all the houses are built out of concrete, up to three stories tall, with the first story usually built as a reinforced 'foundation' building so that other members of the family (usually sons) can build their own house on top of the parent's house as their own family grows.
He said one of the major problems will less reputable contractors there, especially in the regions nearer the coast, is the use of beach sand for construction instead of desert sand. The beach sand's salt interferes with the proper curing of the concrete and causes its strength to be much reduced compared to the desert sand, since Sodium Ions replace Calcium Ions in key concrete formations. He stated this was common knowledge among the literate in Lebanon, although the poor and some cheap rental owners would use those questionable contracts with the risk of the buildings collapsing.
(Score: 2) by Joe Desertrat on Tuesday October 23 2018, @09:12PM (1 child)
The parts that fell were built on "made" ground*. The parts that held up were built on bedrock. If you mark a map of the areas where the worst damage occurred during the quake you will be mapping the areas of the city built on made ground. Such ground liquefies in a quake and tends to shake like jello.
*An area of dry land that has been made by people, generally through the reclamation of marshes, lakes, or shorelines. An artificial fill (landfill) is used, consisting of natural materials, refuse, etc.
(Score: 2) by MichaelDavidCrawford on Wednesday October 24 2018, @01:46AM
It parallels a river one block away, and had quite a lot of damage with two people killed. But elsewhere in Santa Cruz there wasn't much damage. One house was destroyed when its water heater set it on fire, but at my own place there was no damage at all.
When they rebuilt the St. George Hotel in downtown, they used a pile driver to drive extremely long concrete posts all the way down to the bedrock, then rested the new place's foundation on those posts.
Yes I Have No Bananas. [gofundme.com]