Open Thread - Thurs 08 June 2023: Caissons!
Caissons, some roll, some sink, and more...
This is a bit of an exploration of a couple meanings of the word 'caisson'. Why? I dunno. It was a rabbit hole that I went down recently and learned some cool things!
A 1918 caisson for artillery and crew from: here.
The Tyne Bridge, from: here
The word 'caisson' has a few meanings in the English language: according to Encyclopedia Britannica (1911 edition!) it means '(from the Fr. caisse, the variant form “cassoon” being adapted from the Ital. casone), a chest or case. When employed as a military term, it denotes an ammunition wagon or chest; in architecture it is the term used for a sunk panel or coffer in a ceiling, or in the soffit of an arch or a vault.'
There's a third meaning, in civil engineering, where the word refers to a type of under water, or near under water, construction. Here a caisson implies a huge box or enclosure of wood, iron or steel, which keeps water and watery sludge out of the foundation digging area using pressurization while the foundations of the construction are built. I had no idea about this third meaning until quite recently, I must admit.
When I recently was reading about the construction of the Tyne Bridge (more on that below) the word caisson popped up, or maybe, more rightly, it dug down. Immediately it brought to mind, for me, the more military meaning of the word - an ammunition wagon or chest. For some reason 'When the caissons go rolling along' instantly became an earworm which still won't leave me. Especially the 'hi hi hee' part of the song.
The song was written in 1908 by First Lieutenant, and West Point Cadet, Edmund Gruber (related to Franz Gruber who wrote 'Silent Night'). Edmund Gruber (who eventually rose to the rank of Brigadier General) was commissioned in the artillery corps and while serving in the Philippines he wrote the song, 'When the Caissons go Rolling Along'.
John Phillip Sousa made the song into a march in 1917 and it was renamed 'the US Field Artillery March'. In the 1956 the US Army adopted the march, and had new lyrics made for it, as its official song/march - 'The Army Goes Marching Along'.
I have never known the song/march by its official lyrics, but only by those from Edmund Gruber. Why, I don't know. And somehow I learned those lyrics so long ago that I cannot remember when, or how, it happened, but the march is an earworm which won't leave now!
I was reading a book (The Tyne Bridge - Icon of North-East England by Paul Brown) about the building and the history of one of the Tyne's bridges, and I encountered the civil engineering version of the word 'caisson' for, I think, the first time (for me). This was very confusing, as the military march immediately popped into my mind (and my earworm retainer). I had no idea what a caisson was in civil engineering, but the book explained it well (pgs 82-86) and I was left in complete awe and respect.
The book explains that using a huge pressurized steel box, called the caisson, was one of the solutions available and necessary when digging the foundations for large constructions near water; like on riverbanks or in riverbeds, along beaches, across inlets of the ocean and so on. There are famous bridges constructed using this method, including the Brooklyn Bridge in New York, and the Tyne Bridge in Newcastle-upon-Tyne.
The caissons (boxes) used for making the Tyne Bridge foundations were upside down compared to a normal box (the top and sides were sealed steel, the bottom was left open for digging) and kept out the muddy riverside or seaside sludge or waters and made foundation digging possible. The top of the caisson was loaded with concrete which kept it sunk. More concrete was added over time to sink the caisson further as needed. The air inside the caisson was pressurized, so the workers could breathe. The pressurization also kept the water and sludge out of the caisson. Steel shafts and airlocks were used so the workers could enter the caisson, and the material they excavated could be taken up and out of the foundation. The workers dug down, with hand tools mostly, until they hit solid rock.
The caisson was used in bridge construction before the Tyne Bridge was built in the 1920s. In fact, the Brooklyn Bridge in New York was built (in the 1870s mainly) with wooden caissons used to make the foundations. It was hellish work, a 'disturbing and disorienting experience where "everything wore an unreal, weird, appearance": "what with the flaming lights, the deep shadows, the confusing noise of hammers, drills and chains, the half-naked forms flitting about, with here and there a Sisyphus figure rolling his stone, one might, if of a poetic temperament, get a realizing sense of Dante's inferno".' (pg 84 from Brown's book linked above).
While building the Tyne Bridge 20 men worked with pickaxes and shovels in each caisson to dig out the huge foundations needed. The caisson went down a long ways, topped with tons of concrete, at least four stories or more, until the men finally were able to dig into solid rock, not the muddy and soft earth of the riverbank. The work was hard, sweaty, dirty and dangerous. They worked 12 hour shifts! But at least with the Tyne Bridge the shifts were split up to counter decompression sickness (the bends), which could happen when leaving the caisson (five workers died from the bends while building the Brooklyn Bridge) and other problems.
All workers, no matter their job or circumstances, deserve support, encouragement and appreciation. Reading about these workers on the bridges in the late 1800s and early to mid 1900s really brought that home, once again, to me. I always admired the workers who did high rise work in many cities, without safety chains and so on. Now I have added admiration and awe for those who worked under the ground, under the water, to build such amazing bridges and other structures.
And maybe, some day soon, that song/march about the caissons rolling along will leave the earworm docket in my head!
So, thanks for reading about this rabbit hole dive and here's the open thread - and remember, everything is interesting if you dive deep enough, so tell us about where you're diving!