Hong Kong's Famous Bamboo Scaffolding Hangs on (For Now)
121 points - today at 12:08 PM
Sourcealexpotato
today at 3:12 PM
I was in Hong Kong several years ago and saw some of the scaffolding up close.
As a former Boy Scout with a lot of experience in knots/lashing etc, I was VERY curious to see what kind of ropes, knots and lashing they use.
Turns out it's just some flat nylon ribbon and mostly a couple quick wraps and overhand knots.
Really is amazing that it all stays together. I imagine the friction between the ribbon and the wood surface of the bamboo must be high enough to be "sticky".
0xbadcafebee
today at 7:48 PM
It's a simple square pole lashing knot (also known as a japanese square lashing). It works well with almost any kind of cordage. The knot holds the poles in a 90-degree orientation and the finish of the knot tightens the main cord to lock it in place. Natural fiber actually locks better than nylon as it has more 'tooth'. The use of nylon is mostly to resist the elements, adds a bit more strength, is cheaper to manufacture and easy to cut for disassembly.
> mostly a couple quick wraps and overhand knots.
"The toughest part of the job, though, is tying a proper knot to secure bamboo poles, which can take years to master"
Cool sketches of the knots - https://multimedia.scmp.com/infographics/culture/article/318...
I'm sure the years to master includes where and which way to do the knots.
> some flat nylon ribbon
Over 0.5 kN per strip, blah blah boring specs for the scaffolding which at 25 pages would be... 100 times shorter than the EU?
Any who, my bamboo wilted after cutting, you have to treat it it seems... so not even close to the knot stage, but did find the spec'ed lashes, then remembered I hate knots, like just the basic reef knot ones... screw years. Zip ties FTW
As a former construction worker, I marveled at this when I was in Hong Kong a few years ago. We spent so much time rigging scaffolding in the US - these guys just grabbed a bunch of bamboo, some rope, and built platforms tout de suite.
andyonthewings
today at 7:29 PM
Here is a video produced by MillMILK, which is IMO one of the best Hong Kong YouTube channels. They documented how giant bamboo scaffoldings are built on the cliff. I have verified the auto translated Eng subtitles are pretty good.
https://youtu.be/ndf1QcBmQiM
bamboo scaffolding might be one of those examples of where a superior local solution gets replaced by an inferior, yet more scalable generalisable solution. Bamboo is organic, therefore non-standard, therefore harder to track, measure, quantify, maintain - everything you want to do in health and safety, organic material will frustrate. So even though it is better solution in so many ways (cheaper, lighter, flexible, green, man-portable etc) because it is non-standard it ends up being considered unsafe
I think that there are ways to standardize organic components. One of the links provided in another comment to the south china morning post has a good write up on the scaffolding. They show the minimum thickness of the wood as well as the minimum diameter. We know that wood of specified dimensions have the necessary strength. Sure, these components might not be "straight", but as long as they have the minimum specs, they can be considered standardized. Hell, go to your local big box hardware store, either the blue one or orange one, and look at all of the non-straight standardized lumber they offer. People build houses out of that crap
I dunno. Framing lumber is organic, yet we have systems to grade it and charts to show how strong it is (taking into account random imperfections).
Yeah, since they use so much bamboo, it might be feasible to grade the pipes by thickness and/or some other objective measure of strength. Heck, they probably already do, informally.
As for imperfections, the bamboo masters seem to know how to (over)compensate for them, i.e. they build the scaffolding to withstand several times the expected load. As would any good engineer.
AlecSchueler
today at 4:32 PM
> Heck, they probably already do, informally.
I feel like I'm seeing more and more of this kind of conjecture on HN about things that are quite easy to verify.
It also surprises me that anyone would assume they're either operating without any standardisation or that they'd only be doing it informally. It's China, first of all, and it's the 21st century.
The guidelines from the local government are available here: https://www.bd.gov.hk/doc/en/resources/codes-and-references/...
The bamboo is specified by genus, age, drying time, thickness etc. with exact tolerances given for variation.
Hell, even in the 5th century or before, they'd have had enough experience to know that bamboo of certain size would be appropriate or not. Sure, they might not now the exact tensile strength in Netwons or lbs/in or whatever unit, but they'd have enough experience to know that to make a bridge for an ox to cross would need certain sizes of bamboo. Even if that knowledge came from losing an ox or two, it would have been learned quickly enough.
davidcalloway
today at 7:09 PM
I lived in Hong Kong for nearly a year and our building underwent renovation on the facade at the time.
We could open our windows and go up to the roof on the scaffolding.
Good times.
contingencies
today at 2:49 PM
A shame that only zipties are mentioned with no discussion of traditional rope materials. It was interesting to see the Cantonese theater discussed. There is a very active Bangkok Chinese cultural and financial support for Cantonese theater. Every year, around Chinese New Year time, numerous stages are constructed (sometimes with forecourt gates) across the city and Cantonese opera performers are flown in from mainland China. Catch it while you can.
If you look at the pictures where it says "zip ties", they clearly are not zip ties. They are long strands of bamboo.
__mharrison__
today at 4:36 PM
I was in Hong Kong (first time) a week ago.
The bamboo surprised me, so I took a look. I didn't see any zip ties. It looked like it was lashed together with the nylon ribbon that is often used in packing.
Really amazing to see it on 20 story buildings.
The ribbons don't look to me like bamboo. Another commenter here (alexpotato) says the ones he observed up close were nylon.
Foobar8568
today at 7:01 PM
It's nylon, and safety measures are a joke. You will see often workers shirtless/no helm/no safety harness up there.
ThePowerOfFuet
today at 5:41 PM
Cantonese, from mainland China?
Yes. The Cantonese culture as well as the language are very much alive and kicking in Gwongdung and in Gwongsai – the homeland of the Cantonese culture. Both are part of mainland China. The wider area, that also includes Hong Kong and Macau, is known as Lingnan.
Guangdong is mainland China.
Gathering6678
today at 1:32 PM
“the rest of China pivoted toward metal amid an overproduction of steel.”
So the steel is cheaper than bamboo?
The truth is: it is simply not as safe as metal. E.g. bamboo scaffolding has been outlawed in Shenzhen since 1994 [0] due to safety concerns.
[0]: https://www.sz.gov.cn/zfgb/2008/gb622/content/post_4950758.h...
samlinnfer
today at 1:48 PM
It doesn't say bamboo is inherently unsafe, it says due to a shortage of bamboo meeting the required standards (4 years old, 7.5cm for vertical and 9cm for horizontal supports) and construction sites using substandard bamboo as substitute have resulted in collapses in heavy weather conditions.
It's easier just to require steel than to play bamboo police.
Is no one playing steel police?
Waterluvian
today at 1:49 PM
I’m curious what the failure modes are. Is it because of the bamboo or because of the way they’re fastened? Or something else.