Practical Engineering is all about infrastructure and the human-made world around us. It is hosted, written, and produced by civil engineer, Grady Hillhouse. We have new videos posted every first and third Tuesday, so please subscribe for updates.
Practical Engineering: Deciphering Our Constructed World
CONTACT --------------------------------------------- Questions/Topic Suggestions: practical.engineering/about Sponsorship/Business Inquiries: See below
USGS believes the next big one (7.0 and higher) will level 30,000 buildings in San Francisco. When that happens, casualties will be in the thousands, and there won't be enough medical and EMT personnel to begin to dig out the injured and deaths. Repair costs would be in the trillions of dollars. Insurance companies will avoid payouts or risk bankruptcy. Also, there aren't enough laborers (carpenters, plumbers, electricians etc) to recover such a large city. It will be a historic tragedy. Hope I am not around when that happens.
Shocking how much energy production still is generated from petroleum. In 2022, fossil fuels generated 93% of Puerto Rico's electricity, with petroleum-fired power plants providing 63%, natural gas 23%, coal 8%, and renewables 6%. In 2023, renewable energy sources produced 5.03% of the island's electricity consumption and Luma is a terrible monopoly, every citizen should try and go to solar.
So did you cut to the chase and get a round number of what percent of fish make it too and from their spawning ground annually? Or did you let me get away with saying, "it's complicated." Is it about what? 3%? I just googled it
Not sure if it was this black out but i remember when for a week my hometown was in a black out my dad was a senior manager at the time for the hydro company his team was customer service vs the electrical power grid team Even though it wasnt his team He found the issue and came up with a new system, and new devices on houses, if you've herd of or your house has a smart reader, that was one of his projects
Don't forget that distilled water could kill you in an emergency situation. Distilled water has no minerals and takes your bodies nutrients to reach an equilibrium. You CAN drink it, but you don't just drink water for the liquid, you drink it for the vitamins and minerals
The one thing to remember about spending more money to reduce risk, is that there's so many elements to the system. At some point, the bridge is safer than the surrounding roads, so you spend money there instead, and then the intersection design, and even moreso you could be using that money on things like education or fire departments or any number of other things. It's important to remember where else that money could go when you think about why we allow risk
I remember two major power blackouts in Ontario. 2003 and 2013. For both, we were pretty lucky as our power was restored within 18-20 hours. Had to go to work during the first one at night and it was surreal. The building I was working at had emergency power but only for 1/3 lighting, basic emergency systems and one elevator. The second one, I actually got some overtime pay where I had to pick up a generator and deliver it Christmas eve. Was a nice 7 hour drive through some beautiful scenery due to the ice formations. What impressed me though was how much we rely on our power grid for even the basics. We'd be screwed big time if our power was out for more than a week.
Trains have super tiny contact surfaces, made of very hard and very smooth surfaces. Very little friction. So it doesn't take much power to move them, it just takes time. Just as it takes time to move the 2 ton boulder in a pole we have in the city. You can rotate it without any tools, it just goes slowly. Also the reason for why trains can't really go uphill. And down, the same low friction that makes the train slip when going up will also cause it to slop when going down.
While you are discussing bridge replacement; here in Portland, Oregon we need to replace the I5 Columbia crossing. As mate on the USACE Dredge Yaquina we were visited by the design group since we were the tallest vessel that regularly passed under this bridge at 85 feet. My question about the Columbia Crossing is why not build a tunnel? Up stream from the bridge the navigational channel goes to 18 feet from 43 feet downstream. Tunnel vs bridge? What do you think?
I remember crossing the tunnel for the first time when I was a child. I was soooo excited and hyped up, and then..... it turned out to be just a total darkness that lasted a whole boring 30 minutes! These days I'm usually asleep in the Eurostar when I cross.
Nice summation Grady, thank you. I managed the North Island Control Centre for New Zealand in the mid 90s. You pointed out frequency variation - we had a normal operating frequency range of 49.8 to 50.2Hz, as compared to an interconnected continental system as in Europe that would operate at 49.98 to 50.02Hz, quite a significantly more stable frequency. What you didn't mention was the impact of voltage spikes. We used capacitors to boost the voltage in the main demand centre of Auckland. But switching the capacitors in and out with the wrong grid conditions would impose voltage spikes on the grid, that more than once tripped off the oil refinery in the north of the North Island. My point here is that the variability of both frequency and voltage on very small island power systems presents problems for control electronics designed for large stable interconnected systems. Something to remember when deciding on the build of a refinery!
They just did the controlled explosions of the bridge. The Coast Guard commander (two star at the mike) metioned they did a lot of calculations in terms of where to put charges, how large they should be and the milliseconds between them. Grady, can you walk us through what they did in more detail.
The obvious solution is to go back to using galleons for transporting goods over the ocean. I've never heard of a bridge collapsing from a galleon crashing into them.
Have to say, I've seen a lot of your "What went Wrong" vids, and I never once thought that one would happen so close to home. I was awake when it happened, and I live on the water in Baltimore... So, saying this hits close to home, is an understatement, to say the least
