Crowded dock collapses on University of Wisconsin campus 1

[FacEngrPE]

If there is space someone will stand on it.

https://youtu.be/_KxhV9y5x5Q

Aftermath
Looks like a rent-a-pier.

https://youtu.be/xRUtMoe-mCs

 

[bugbus]

I'm always reminded of this picture that someone posted here once...

Hard to see the collapsed part, but the rest of it doesn't look ridiculously overloaded. Maybe 3-4 kPa of live load?

 

[MortenA]

I dont know what "rent a pier" is - but many small piers like this is construct so they can be removed in the fall if ice is a problem.

--- Best regards, Morten Andersen

 

[IRstuff]

Looks kind of like this one

https://www.google.com/maps/place/U...76592!4d-89.4124875!16zL20vMDF5eDFi?entry=ttu

so looks permanent

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[IRstuff]

Looks pretty flimsy from Street View

https://www.google.com/maps/@43.076...qrQQbfqutL3HxsMQ!2e0!7i13312!8i6656?entry=ttu

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[phamENG]

Little piers like that are commonly designed for only 40 or 50psf live load. Given the location near commercial/institutional buildings and the lack of access controls I would think 100psf would have been prudent, but a lot of "turnkey" and "prefab" solutions get picked without really considering what the assumptions are. This looks like a common residential pier. Flimsy, but common.

 

[LittleInch]

I googled a few modular type jetties and the brochures mention many things EXCEPT max loading.....

I think they just don't think they are going to be used like the pictures show.

They also look like aluminium if the picture of one man carrying a frame with ease is anything to go by....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[EdStainless]

These have to be light weight so that they are easy to remove each fall before any ice formation.
These are not permanent structures.
And they just sit on pads on bottom.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[racookpe1978]

At its anniversary, the Golden Gate Bridge was closed to traffic, left open for people to "walk across".

The combined weight of the total crowd visibly deformed the bridge deck, deflecting it so much the vertical cables were flopping loose in the breeze where the deck moved up. And strained so tightly where it was forced down that the suspension cables were also deflected.

 

[JohnRBaker]

On Labor Day, they also allow people to walk across the Mackinaw Bridge connecting the Upper and Lower Peninsulas of Michigan. I've never done it, but my mother made the walk several times.

Of course, this event is eclipsed by a similar 'bridge walk' which takes place the same day, Labor Day, in Lovells, Michigan:

October 2018 (Sony a6000, 16-50mm)

And yes, that's the 'bridge'. Note that there's a bar just around the corner to the left.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[FACS]

The piers are not meant for large gatherings. This area is part of the UWM system, and used to be reserved for students, faculty and alumni only. The piers are mainly a place for people to dock their boats to go ashore and enjoy the many restaurants in the area. Now, they do not enforce the student only policy as we can go there and enjoy it anytime we want, but usually in the summer when there are few students. I've been there many times; they have boat rentals, Kayaks, paddle boards, etc... and the piers are for those usages also.

Since school just started, many students flock to this area as it is a great place to hang out. No one expected them to completely fill the piers, they usually just lay around sun bathing.

These piers are NOT PERMANENT. They are lightweight and are taken out every fall and put back in the spring. I have installed a few of these, and they can be done by one person if need be. Many have wheels on them and in the water they are even lighter. All piers are taken out of our lakes because the ice will destroy them. I left just the first section in one winter for ice fishing, and it was gone by spring.

This is really a non story as it is not the first time it's happened, and it will not be the last. Kids are warned, but they will do what kids do.