Right now this looks like a Darwin award candidate. They're very lucky that those walls contained enough rebar vertically to withstand this load, it's at the worst possible attachment point and at the worst possible angle (especially for the inner wall).

Edit: looking more closely at the picture it seems as though the cables under tension are actually running through the drainage ports of the back wall, the ropes at the top seem slack or loaded both top and bottom of the opposite so there is in fact mostly compressive load on the front wall and about 50% of sideways load on the opposing wall. Still, that structure was definitely not meant to be loaded like this.

So I "think" most of the load would be applied vertically, but that would be my biggest concern still.

Still seems a bit stupid to put that much additional load on a 70 year old pedestrian bridge though.

Based on that it was definitely built for higher load than just a few pedestrians.

Edit: The German language Wikipedia article actually confirms this [1]. It states that the bridge was built for a traffic load of 13 tons and that the new bridge was built in 1993 to increase capacity. The old bridge was thoroughly renovated after the new bridge had been constructed. The bridge actually is well documented and is under protection as an architectural landmark. It was exhibited in the MoMA for a long time.

Based on the amount of prep these guys put into this and the available documentation I don't see why they should not have checked if what they wanted to do is possible.

[1] http://de.wikipedia.org/wiki/Pont_de_Gueuroz

Edit 2: Some fascinating pictures from the time of construction: http://www.swiss-timber-bridges.ch/detail/193

That's weird. It definitely looks like it is the same bridge but that page says it has been removed.

The construction clearly shows a concrete bridge in the making (lots of concrete forms visible) whereas the heading of the page is 'Swiss timber bridges'.

No net sideways force. Any +X force on the left wall will have a -X force on the right wall. If there's a tension T in the ropes across the top they'll be pulling the walls inward with a force of T causing a torque of T*height.

Almost, you'd still have to subtract the friction component across the 90 degree angle where the cable hangs down from the edge near the porthole but that's probably relatively small compared to the total (depends on cable material and any kind of padding they put in between the cable and the concrete).

It would have been a lot better to sling those cables through the portholes on both sides and to make it loop the bridge, one person would have to rappel down to get that started but you'd have zero load on the walls.

The longer I think about this the more I think those guys and girls were extremely lucky and I hope that this will not inspire any copycats to try this with other bridges or even the same one. It's a long way down.

Apparently the bridge carried cars at one point (http://en.wikipedia.org/wiki/Gueuroz_Bridge) so the wall was rated for vehicle impacts, which is good.

Why they went over the top of the walls I don't know, I think they wanted to measure the ropes exactly instead of adjusting it the day of. Like, that was where they drew the line of "unacceptable risk"? I agree a loop through the drain holes would have made their lives easier in a bunch of ways, except the tripping hazard would have made it a very risky project...

Spherical cows look so much nicer too ;)

If that thing weighed 6 tons they may have made it out of the "designed to handle" range and into the "safety factor" range of inward forces on those walls. Surely those drainage ports weren't designed to handle upward loads?

I really can't believe some of them took their harnesses off while in the pool.

[0] - https://www.physicsforums.com/threads/wind-speed-100mph-to-p...

Some more evidence that they had considered these things would have been nice, but civil structures are quite a bit stronger than people here seem to be giving them credit for. For example, the vertical design load from people walking on a bridge like this is something like 100 lb/ft^2. Meaning the bridge is designed to hold one jacuzzi every 10 or 15 feet, depending on how wide it is.

It seems like it would have been a better idea to bring the cables/ropes in through the hole at the bottom of the wall, rather than over the top. The lateral compressive load would then have been taken up by the bridge itself, rather than the walls.

20 sweaty alpinists in one tub :)

I may sound like a hater, but I would certainly understand the frustration of those having climbed Mont Blanc only to find a bunch of party-people in there (if that really was the case for their looks).

And a serious question: How do these people have money and especially free time for this?

Later edit: Before people start down-voting me, I found this comment of a guy who was among the "other" people on the top of Mont Blanc (meaning he was not invited to the jacuzzi party). He pretty much disapproves of it all, with quite good reasons (text is in French):

> Me trouvant avec mes deux clients au sommet du Mt Blanc ce 13 septembre, je ne peut que vous faire part de notre consternation devant la débauche de bruit et d'agitation ridicule qui polluait l'endroit ce jour-là. Est-ce paraître pisse froid que de ne pas partager votre enthousiasme pour cette réalisation qui contribue à rabaisser un sommet majeur au rang d'exutoire de nos névroses et théatre de nos délires les plus vains ? En a t-il subi, ce pauvre Mont Blanc, des idées absurdes : la tentative de descente en voiture, celle en poële à paella, une autre en VTT et j'en passe. Victime d'égos surdimmensionnés, les sommets phares sont chaque jour dévoyés par des personnes donnant de l'alpinisme une image aberrante (CF la tentative de l'ascension de l'Everest...en short ! Vous y verra-t-on bientôt en mailot de bain ?).Promotion dont nous nous passerions bien à l'heure ou nos effort tendent à rendre à ces montagnes leur véritable statut. Mes clients n'avaient-ils pas le droit de jouir au terme d'un effort que vous avez vécu, d'un sommet conforme ou presque à leur idéal ? Il me semble que cette façon de s'approprier un lieu au mépris des nuissances causées à l'égard des autres personnes qui le fréquente, celà sans autre objectif que de s'offrir un délire de potaches se situe à la limite del'incivilité. Salutations. Denis Crabieres, guide de montagne, secrétaire du syndicat national des guides de montagne

We got the same flack from the guides (and the police, but that was fair TBH) when we did the massive paragliding group landing summer 2012

[NB I am biased by personally being quite miffed at the protectionism of French ski instructors]

Not that I don't agree with the higher standards required - in other alpine countries you see a lot of anglo-saxon "instructors" who clearly wouldn't be able to pass the tests.

Having said that, I know of one large French ski area that seems OK with it but I won't say which one it is... :-)

Finding myself with my two clients to the summit of Mont Blanc on September 13, I can only share with you our dismay at the sound of debauchery and ridiculous agitation that was polluting the place that day. Is it seem colder than piss do not share your enthusiasm for this achievement that contributes to belittle a major summit to the rank of outlet for our neuroses and theater of our most vain delusions? As he suffered, the poor Mont Blanc, absurd ideas: the attempt to drive down, the stove in paella, another mountain bike and so on. Victim of egos surdimmensionnés, headlights summits every day misguided by people giving mountaineering aberrant image (CF attempt to climb Everest in shorts ...! You will soon do we see bathing Mailot?). Promotion which we would move us well on time or our efforts tend to make their true status in these mountains. My clients had they not entitled to enjoy after a strain that you experienced, a consistent top or near their ideal? It seems to me that this way of taking a place in defiance of nuisances caused against others who frequent it, it no other purpose than to provide a delirium of schoolboys del'incivilité is at the limit. Greetings. Denis CRABIERES, mountain guide, secretary of the National Union of Mountain Guides

Doesn't seem to be that costly, especially since they reuse the equipment. As for the time, they probably just take vacation days.

As opposed to mountain climbing at all? Or any endurance sport? Or commenting on internet forums? Or hobby computing?

Please show us your math on the amount of time and money spent on this versus being a marathon runner or an open-source contributor.

De gustibus non est disputandum.

That this is a serious question shows how sad the world we're living in is.

Often with sports climbing you'll see the person belaying (at the bottom holding the rope) wearing a helmet, while the person half way up the climb isn't - the risk is the climber will drop something on the person at the bottom.

But I'll admit: these folks know how to scale.

The Latin name is used to avoid favouring any one of the four official languages (German, French, Italian, Romansch).

No matter what random challenge tomorrow brings this group of people is probably better equipped to deal with it than most social groups who have never tackled anything like this together. Of course they may not be great at handling the mundane, and that might be what drives them to hang jacuzzis off bridges.

(From Wikipedia):

The generally accepted highest summit is Mount Elbrus (5,642 m or 18,510 ft) in the Caucasus, appearing on both the Bass and Messner lists. However, because the location of the boundary between Asia and Europe is not universally agreed upon, its inclusion in Europe is disputed: if the Kuma–Manych Depression is used as geological border between Asia and Europe, Caucasus and Elbrus lie wholly in Asia. If the Greater Caucasus watershed is used instead, Elbrus' peaks are wholly in Europe, albeit close to the border with Asia. Mont Blanc (4,810 m or 15,781 ft), lying on the border between France and Italy in the Graian Alps, is seen by some to be the highest mountain in Europe.

"It is home to the Caucasus Mountains, which contain Europe's highest mountain, Mount Elbrus"

http://en.wikipedia.org/wiki/Caucasus

NB I've always thought of Europe stopping at the Urals, the Caucasus and the Bosphorus.

Pulled up by winch?

Hand over hand climbing (ouch) or manually but assisted by equipment (e.g., I can imagine one-way sliders on the rope that'd let you climb with leg power)?

I did my share of rappelling when I was a teenager, but never had to climb back up the way I'd come with nothing but the rope....

[1]: http://en.wikipedia.org/wiki/Ascender_(climbing)

1. http://en.m.wikipedia.org/wiki/Ascender_%28climbing%29

((I really hope I got the knot name right.))

I don't think I could bear to take off my harness, though. Getting clothing off would be a conundrum... either that or a very cold descent.

Might get some serious nylon burn though, as you say.

Someone posted an imgur screenshot to HN with a title something like "bug on HN today". This was within the past day or so.

The Algolia search is fucking hopeless so I can't find the submission now.

That's like every single person in NYC being made homeless.