The Hidden Engineering of Liquid Dampers in Skyscrapers
13 comments
·July 1, 2025ggm
The non liquid active tuned damper in Tapei 101 is a delight. Sprayed gold like a funky futurist nugget, set amongst massive hydraulic actuators.
I'm not sure you could make a liquid tuned damper be a tourist attraction.
chiph
I don't recall him mentioning how the viscosity of the fluid changes it's effectiveness, but I imagine it would. For reduced maintenance costs (prevent algae growth) they probably use mineral oil, not blue water.
kllrnohj
Surely some biocide or glycol or whatever is going to be a lot cheaper than using mineral oil? This is solidly north of a hundred thousand gallons after all, right? Especially since they're already going to have plumbed water in the building anyway, so they wouldn't need to transport drums and drums of whatever liquid is chosen if it's not water?
exmadscientist
300-400 tons of mineral oil is not expensive on industrial scales. And biocides are not as effective as you'd hope (look up biofilms for one particularly annoying example). So mineral oil is definitely a viable option. But its lower density means that water is probably going to win anyway.
kllrnohj
Quick search says around $1,600 USD per ton for mineral oil? Taipei 101's damper is 660 tons. No idea how that compares to a fluid damper, but if we assume similar tonnage requirements that'd work out to somewhere in the range of $1M USD in mineral oil. Granted that's, what, 0.05% of the building cost? So in that sense "not a lot", sure, but compared to the almost nothing that it'd cost for an equivalent amount of industrial water, that still affords a lot of alternative solutions. Especially since it just needs to slosh around, does it even matter if stuff grows in it? It's not like there's going to be sunlight, either, so there wouldn't be much growth regardless right?
bluGill
They want something that isn't a fire hazzard. And water can be connetted to the fire control system thus serving an additional purpose.
Toward the end, he suggests water dampers serve a dual purpose to meet fire codes (having a reservoir of water atop your building).
Does this create additional risk when firefighting operations draw it down?
i.e. Do the dampers contribute meaningfully to short term structural integrity of the building (particularly in gusty weather), or are they mainly just for comfort and materials longevity?
Has any building architected its liquid pool damper as a bonafide swimming pool?