Why are public demolitions now done in such an inefficient (looking) way?

hatrickpatrick

Was watching a video this afternoon of the demolition of a block of council flats behind a friend's house in Dolphin's Barn, which are to be partially demolished and rebuilt to a better standard. Essentially, they seemed to be using a JCB's claw to literally rip chunks of the building down, piece by piece.

https://www.facebook.com/paulphand/videos/415541138644074/

My question is, why don't they use either explosive or wrecking ball (with or without Miley Cyrus on it) demolition techniques anymore? Strikes me from watching this that the technique they're using here would take hours, and indeed I think they left part of the building standing the first day because they didn't get all of it down in one go, presumably to return the next day and finish the block.

Could they not have had the entire job done in minutes if they'd used an implosion? A wrecking ball style demolition probably wouldn't have been appropriate since only some of the blocks are to be demolished while others are to be retained, but I don't see why controlled explosive charges couldn't have been used to get it done much more cheaply and quickly.

Anyone know anything about these things? What's the advantage of using heavy machinery to do this slowly, when it could be done much faster using other means?

Guy:Incognito

The set up time for explosives is fairly long is it not? I'd imagine it takes much long than the chosen method when thats factored in. Though I highly doubt thats the only reason.


Maybe they're afraid of the locals getting their hands on the tnt

cerastes

I'd have thought it would be reasonably obvious to even guess at some possibilities.
There is probably a risk of shock waves causing damage elsewhere, ie in other properties or to damage or other elements such as drains? potentially made from baked clay or concrete.

Even if that's less than likely, then any instances of problems or even just things noticed will be attributed to the use of explosives, aside from the possibility of actual damage, then it could be an insurance issue. It would seem less likely to have any impact on people around and cause less disruption, people may need to be moved and if there are a lot of different ages of people with varying needs this might be costly and inconvenient.

Instead of applying all or most of the energy required to demolish something in a short space of time, it's been done bit by bit, anything going awry would likely not have as serious an outcome.

Put it like this, if some structure beside or near you was to be demolished, would you want it blown up or even had small amounts of explosives used on it, or just have it torn down?

Lucena

I don't work specifically in demolition, but in bridge and roadwork. Damage (or perceived damage) to surrounding property is always a huge concern, so I'd imagine that's the reason. Also even during a controlled explosion, there's going to be dust everywhere.

SuperS54

It looks like it's only 3 stories high? Cost of explosives and associated experts would be far higher than the cost of the method being employed, not to mention impractical in that area.

hatrickpatrick

SuperS54 wrote: »

It looks like it's only 3 stories high? Cost of explosives and associated experts would be far higher than the cost of the method being employed, not to mention impractical in that area.

They're all four storey blocks. The explanations given here make sense though, I was just watching it (and another similar block further up Cork Street earlier in the year) and thought it looks a painfully slow method of bringing it down. I'm surprised they don't at least use a bigger claw!

neddynasty

They brought Pairc Ui Chaoimh down in a similar fashion recently. It took months. They weren't demolishing all of it, maybe about 85% but I thought they'd have used a wrecking ball at least. It was a machine mounted jackhammer type drill and JCB effort. Some pics in the link.

http://www.irishexaminer.com/ireland/complaint-after-part-of-paacuteirc-uiacute-chaoimh-stadium-stand-knocked-343803.html

Mahogany Gaspipe

Wreaking ball demolition was not a particularly controlled or safe method of bringing down buildings.
As a form of demolition it is much less effective than the hydraulic excavators which, in any case, are likely to be required to be brought on site to process what the wreaking ball could not.

galwaytt

....it's a common method of demolition, outside construction too: https://www.youtube.com/watch?v=um77vmJ-ys8