Practical Engineering
Published Jun 18, 2024Why Fern Hollow Bridge collapsed.
This is a crazy case study of how common sense can fall through the cracks of strained budgets and rigid oversight from federal, state, and city staff. And the lessons that came out of it aren’t just relevant to people who work on bridges. It’s a story of how numerous small mistakes by individuals can collectively lead to a tragedy.
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September 29, 2024
This Bridge Should Have Been Closed Years Before It Collapsed
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May 31, 2024
How To Install a Pipeline Under a Railroad
Practical Engineering
Published Feb 20, 2024I’m on location to document the installation of a water transmission line below two railroad tracks.
Huge thanks to our project partners!
Owner: Crystal Clear Special Utility District
General Contractor: ACP
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May 26, 2024
Evolution of The Churchill Tank | “No Damn Good”?
The Tank Museum
Published Feb 17, 2024Designed by a company that had never built a tank before with the Prime Minister, Winston Churchill, looking over their shoulders and plagued by mechanical teething troubles, the Churchill tank had unpromising beginnings. Despite this, it became one of the most successful British tanks of WW II: heavily armoured, not fast but with superb climbing ability, the Churchill served not only as a gun tank but the basis many of the specialised vehicles that helped the British and Canadian Armies ashore on D-Day.
00:00 | Intro
01:20 | History – What was needed?
03:38 | Design, Weaponry and Armour
08:44 | Up-gunned and Upgraded
13:59 | A Look Inside
17:51 | Combat Performance
20:23 | Multi-use Platform
23:10 | ConclusionThis video features archive footage courtesy of British Pathé.
#tankmuseum
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April 21, 2024
How The Channel Tunnel Works
Practical Engineering
Published Jan 16, 2024Let’s dive into the engineering and construction of the Channel Tunnel on its 30th anniversary.
It is a challenging endeavor to put any tunnel below the sea, and this monumental project faced some monumental hurdles. From complex cretaceous geology, to managing air pressure, water pressure, and even financial pressure, there are so many technical details I think are so interesting about this project.
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April 1, 2024
How Railroad Crossings Work
Practical Engineering
Published Jan 2, 2024How do they know when a train is on the way?
Despite the hazard they pose, trains have to coexist with our other forms of transportation. Next time you pull up to a crossbuck, take a moment to appreciate the sometimes simple, sometimes high-tech, but always quite reliable ways that grade crossings keep us safe.
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March 23, 2024
The Roman Army’s Biggest Building Projects
toldinstone
Published Dec 15, 2023The greatest achievements of the Roman military engineers.
Chapters:
0:00 Introduction
0:38 Marching camps
1:36 Bridges
2:40 Siegeworks
3:26 PIA VPN
4:32 Permanent forts
5:49 Roads
6:24 Frontier defenses
7:41 Canals
8:21 Civilian projects
8:54 The aqueduct of Saldae
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March 11, 2024
Why Railroads Don’t Need Expansion Joints
Practical Engineering
Published Dec 5, 2023A friendly overview of thermal effects on railways.
Errata: At 9:00, the left column of calculations is incorrectly labeled “SI.” It should be imperial. Whoops!
Just as all materials have a mostly linear relationship between temperature change and length change, all materials also have a similar relationship between stress and change in length (often called strain). And this is part of the secret to continuous welded rail: restrained thermal expansion. You can overcome one with the other.
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March 2, 2024
QotD: Early siege warfare
Now the besieger’s side of the equation may seem like an odd place to start a primer on fortifications, but it actually makes a fair bit of sense, because the capabilities of a potential attacker is where most thinking about fortification begins. Siegecraft, both offensive and defensive, is a case of “antagonistic co-evolution“, a form of evolution through opposition where each side of the relationship evolves new features in response to the other: neither offensive siege techniques nor fortifications evolve in isolation but rather in response to each other.
In many ways the choice of where to begin following that process of evolution is arbitrary. We could in theory start anywhere from the very distant past or only very recently, but in this case I think it makes sense to begin with the early Near Eastern iron age because of the nature of our evidence. While it is clear that siege warfare must have been an important part of not only bronze age warfare but even pre-bronze age warfare, sources for the details of its practice in that era are sparse (in part because, as we’ll see, siege warfare was a sort of job done by lower status soldiers who often didn’t figure much into artwork focused on royal self-representation and legitimacy-building).
But as we move into the iron age, the dominant power that emerges in the Near East is the (Neo-)Assyrian Empire, the rulers of which make a point of foregrounding their siegecraft as part of a broader program of discouraging revolt by stressing the fearsome abilities of the Assyrian army (which in turn had much of its strength in its professional infantry). Consequently, we have some very useful artistic depictions of the Assyrian army doing siege work and at the same time some incomplete but still very useful information about the structure of the army itself. Moreover, it is just as the Assyrian Empire’s day is coming to a close (collapse in 609) that the surviving source base begins to grow markedly more robust (particularly, but not exclusively, in Greece), giving us dense descriptions of siege work (and even some manuals concerning it) in the following centuries, which we can in turn bring to the Assyrian evidence to better understand it. So this is a good place to start because it is the earliest point where we are really on firm ground in terms of understanding siegecraft in some detail. This does mean we are starting in medias res, with sophisticated states already using complex armies to assault fairly complex, sophisticated fortifications, which is worth keeping in mind.
That said, it should be noted that this is hardly beginning at the beginning. The earliest fortifications in most regions of the world were wooden and probably very simple (often just a palisade with perhaps an elevated watch-post), but by the late 8th century, well-defended sites (like walled cities) already sported sophisticated systems of stone walls and towers for defense. That caveat is in turn necessary because siegecraft didn’t evolve the same way everywhere: precisely because this is a system of antagonistic co-evolution it means that in places where either offensive or defensive methods (or technologies) took a different turn, one can end up with very different results down the line (something we’ll see especially with gunpowder).
Bret Devereaux, “Collections: Fortification, Part I: The Besieger’s Playbook”, A Collection of Unmitigated Pedantry, 2021-10-29.
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January 26, 2024
Which Is Easier To Pull? (Railcars vs. Road Cars)
Practical Engineering
Published Nov 7, 2023A lot of the engineering decisions that get made in railroading have to do with energy. How does the rolling resistance of a 20-ton freight railcar compare to my little grocery hauler?
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January 7, 2024
Every Type of Railcar Explained in 15 Minutes
Practical Engineering
Published 19 Sept 2023How many of these cars have you spotted before?
Trains are one of the most fascinating engineered systems in the world, and they’re out there, right in the open for anyone to have a look! Once you start paying attention, it’s pretty satisfying to look for all the different types of railcars that show up on the tracks.
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January 1, 2024
The largest telescope that will ever be built*
Tom Scott
Published 2 Oct 2023The asterisk is important.
■ More on the ELT: @ESOobservatory https://eso.orgThe Extremely Large Telescope, in Paranal, Chile, is probably going to be the largest optical telescope that will ever be constructed. I was invited out there by the UK Science and Technology Facilities Council and the European Southern Observatory, and I wasn’t going to turn down a chance like that.
📰 DISCLAIMER
While the STFC and ESO invited me and arranged the logistics after arrival into the Antofagasta region, I was not paid for this (not even my travel costs) and I have sole editorial control over the video. This is not an advert.
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December 30, 2023
Building the Walls of Constantinople
toldinstone
Published 15 Sept 2023This video, shot on location in Istanbul, explores the walls of Byzantine Constantinople — and describes how they finally fell to the Ottoman Turks in 1453.
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December 16, 2023
Do Droughts Make Floods Worse?
Practical Engineering
Published 5 Sept 2023The answer isn’t as simple as you might think!
One statistician famously said, “All models are wrong, but some are useful”. And even something as simple as the flow of water into the soil has so many complexities to keep track of. Like most answers to simple questions in engineering and in life: the answer is that it’s complicated.
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December 3, 2023
Every Construction Machine Explained in 15 Minutes
Practical Engineering
Published 15 Aug 2023A very quick overview of nearly every machine you’ll see on a construction site.
It takes a lot of big tools to build the roads, dams, sewage lift stations, and every other part of the constructed environment. To me, there’s almost nothing more fun than watching something get built, and that’s made all the better when you know what all those machines do.
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November 2, 2023
Keeping Clean in Rome
seangabb
Published 2 Jul 2023A lecture, given in June 2023, about bathing and keeping clean in the Roman World — plus an overview of depilation and going to the toilet.
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