Tram and South Rd closed - for a worrying reason

[OlympusAnt]

there's no easy fix for that either

How long do you reckon?

Seems to me they would be better off to just to remove the section entirely, close down the bike path, let traffic flow as normal, get their shit together, then come back one weekend and attack it.

depends on how long they want to take

[Ben]

Does anyone know the cause yet? Why this infrastructure would suddenly tilt without an earthquake type event. It should be built to withstand an earthquake in any case.

[Llessur2002]

That's what made me wonder about failure of the expansion joint due to, well, thermal expansion.

Or....has a(n albeit very) tall vehicle hit it overnight and driven off?

How does this happen:

without an external force being applied? From the pictures there's no visible movement or cracking in the concrete piers but then again there's no visible impact damage either...

Has the joint been installed in such a way that with each expansion and contraction cycle the rubber block shifts slightly before finally reaching a point where the center of gravity of the beam has moved enough for it to topple?

It's like a very poor episode of Murder She Wrote. But with bridges. And no murders.

[AG]

The type of failure evident here is an torsional displacement about the main longitudinal axis. It is true that the beam would contract and expand due to thermal variations (hence the flexible bearings at each end to accommodate this), however the expansion and contraction would happen along the length rather than the width of the beam.

Because of the tall and narrow length of the beam, it's possible any significant eccentric (off centre) loading such as the side barriers may have contributed to the beam rotating as well, although not necessarily the cause of the failure in the first place.

(Structural engineer involved in other bridge projects)

[OlympusAnt]

what's the fix?

[Goodsy]

what's the fix?

pick up that section with a crane and put it back down I guess?

[bits]

How does this happen:

I think you need to see all contact points that have or had a force being applied.
I could imagine the rest of the structure somewhat twisting and picking up the piece and placing it down in to this position. Over a long period of time. In fact this looks a repeated lift up, move right, place down, move left kind of movement.

1)The tram weight might lift and move parts at the other end of a section it is currently on. Vibrations would assist movement.

2)Or the main support from underneath where the tram part just has a lot more play to accept the movement or the current movement just flukes that it isn't impacting the tram bridge contact points as badly or it has huge problems also which we just do not know about yet. You need to consider those uprights as a full 3d object which can twist and manipulate all kinds of ways.

3)Or perhaps the force is coming from the horizontal up there where the end(s) twist and drags the center piece wherever it is going due to how it is fixed together or just pressure coming inwards to the center.

4)Or mount points are failing and the structure has an unbalanced weight load which causes it to want to twist under its own weight which it can no longer correctly hold.

Main point is I think the picture is showing you the result of somewhere else which moved.

[bits]

There is a cement patch work where it looks like the "floating" center beam has hit/crushed. Is that brand new work this week? Or has this bridge moved heavily to that side, hitting before and is now moving back but this time without its little foot block coming with?

[Llessur2002]

There is a cement patch work where it looks like the "floating" center beam has hit/crushed. Is that brand new work this week? Or has this bridge moved heavily to that side, hitting before and is now moving back but this time without its little foot block coming with?

Also wondered about that, but maybe it was damaged during installation?

[SouthAussie94]

Streetview could hold the answer to the age of the patch, or at least give a few clues as to when it appeared..

[Llessur2002]

[monotonehell]

Temporary repairs are expected to be completed overnight, and be open to traffic Saturday.

Also on the lighter side:

Adelaide's broken South Road bridge put on eBay, passes $100k in bids
A satirical selling of Adelaide's broken South Road bridge has attracted more than $100,000 in bids and hysterical comments.

The eBay listing describes the bridge as "a little wonky but still has plenty of life in it" and boasts the bridge will "make a great farm bridge for getting those milkers across the creek". "You will need to bring a couple of mates with trolley jacks," the ad also stated.

Bids started a $1 but have since skyrocketed as people got in on the joke. One prospective buyer asked, "Will you swap it for my '86 VL Holden Commodore" to get the reply: "Has it got mags?"

The South Road bridge is expected to have temporary repairs completed overnight. South Road, from Anzac Highway to Cross Road, was closed to traffic on Wednesday morning after fallen debris from the bridge was found. The area is expected to be reopened to traffic Saturday.

http://www.abc.net.au/news/2017-01-20/a ... 0k/8197992

[OlympusAnt]

South Rd is back open again

[BillD]

Here's a shot of one of three temporary bracing brackets which have been fitted to the overpass. Large-diameter threaded rods run from these brackets up through holes drilled through the footpath deck where they are fixed to secure the path. Wooden wedges have also been installed between the beams and the beam's supporting structures.
During the work, Laser distance measuring equipment watched for further movement in either of the two beams which have rotated/shifted.

Bill.

[timtam20292]

Should we be concerned or is this a classic case of fear mongering?

"WATCH: An urgent safety check on the O-Bahn tunnel amid revelations of a link to the crippled South Road overpass."

https://twitter.com/i/web/status/823796180878430209