Manhole cover failure at Lanseria

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dollar
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Re: Manhole cover failure at Lanseria

Unread post by dollar » Thu Nov 08, 2018 8:42 am

I am in the manhole business - albeit somewhat indirectly.

Our general rule is that you use a standard heavy duty cast iron manhole covers in a roadway (or anything that can be used as a roadway). Assume that a big truck will drive over it at some point - even if there are no trucks in sight!

Also assume that the purpose of the roadway may change over time and that trucks will eventually drive over it. During the construction phase your own trucks will seek out weak manhole covers! Things like cement trucks spring to mind.

At an airport you will also, occasionally, see a big red/yellow truck loaded with water/foam dashing around. Your manhole covers need to be up to what can be driven on the roadway - not what you think should be there. Painting it red is not particularly useful.

Engineering fail - the tar and the cover :D
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Re: Manhole cover failure at Lanseria

Unread post by dany » Thu Nov 08, 2018 9:45 am

All depend on the design and specifications. In the industry there is no place for "think or Gues". In the end, it is down to budget , design and costing. And in the end, the end user pays. We did a survey on a parking apron some 4 or 5 years ago,and it was just just with specs (soil weathering took away the % of safety factor over years)after all the weathering. To bring it back to standard or upgrade would have cost R15 m. Airport in question decide to change the SOPS for that part (new demarcation)and put the upgrade in their ten year plan.

Not sure, where is the architects here 8) . They normally collect all the specification lists,think this one is covered by SANS 50124 ? and classification of the actual manholes falls in class A15 to Class F900.

By the looks of it, seems the fail come from the actual manhole sub surface structure. The lid broke due to lateral force applied otherwise it would have been all down the manhole in more broken pieces as it is now.

Now back to different areas and its demarcation and what is SOP for that specific areas and who signed on the dotted line. Bottom line, interesting scenario and also would like to see the play-out,as same with aviation, all can learn from Airport design and built.

BTW, a interesting video on design, proper markings and human behavior.
Last edited by dany on Thu Nov 08, 2018 9:56 am, edited 1 time in total.
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Re: Manhole cover failure at Lanseria

Unread post by HJK 414 » Thu Nov 08, 2018 9:56 am

dollar wrote:
Thu Nov 08, 2018 8:42 am

I am in the manhole business - albeit somewhat indirectly.

???????????? ............. :mrgreen:

.
manholes.jpg
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Re: Manhole cover failure at Lanseria

Unread post by Oldtimer1 » Thu Nov 08, 2018 11:04 am

This thread reminds me of a story I actually played a part in years ago when we were young and armed to the teeth.......

In 1986 at Ondangwa a SAAFAIR C130 got stuck in the tar crossing from the hardstand at movements to the taxiway. If I remember correct only first view crossings between the hardstand and the taxiway was strong enough to carry the load of a C130 and this one turned out one crossing further up closer to the chopper hangar.

I still drove to Ondangwa roads department and fetched a bunch of grader blades which we stuck in front of the wheels, I actually slid on my back in under the C130 behind the wheels to move the grader blades over to the inside as well in order to ensure the tyres go onto the steel fully. That was a tight squeeze and I constantly hoped the aircraft have settled in the tar ad won't sink deeper, two inches deeper and I would not have been able to crawl out. The C130 used its engine power to lift itself out of the tar and onto the steel and it took off away to wherever. I then had to return the grader blades to Ondangwa Roads Dept.
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richard C
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Re: Manhole cover failure at Lanseria

Unread post by richard C » Fri Nov 09, 2018 10:29 am

This has nothing to do with the Architect, Dany. All engineering specs.

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dany
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Re: Manhole cover failure at Lanseria

Unread post by dany » Fri Nov 09, 2018 11:53 am

Fully understand Richard :D . I only mention architects as in our circles they always close at hand with the various gov standards besides the Engineers. Anyway, I was not sure of the correct Sans doc,but confirmed with our office it is right. Sans 50124.And also the different classifications.
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Re: Manhole cover failure at Lanseria

Unread post by Artfly » Fri Nov 09, 2018 12:27 pm

eisch ! expensive incident for somebody
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Re: Manhole cover failure at Lanseria

Unread post by MadMacs » Fri Nov 09, 2018 1:52 pm

It looks like the tyre that sank into the tar transferred it's weight to the tyre going over the manhole cover which probably exceeded the covers design load.
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Re: Manhole cover failure at Lanseria

Unread post by heisan » Fri Nov 09, 2018 2:13 pm

MadMacs wrote:
Fri Nov 09, 2018 1:52 pm
It looks like the tyre that sank into the tar transferred it's weight to the tyre going over the manhole cover which probably exceeded the covers design load.
Well, either the chicken or the egg... Seeing as there is no sign of an impression in the tar up to that point, I would say it is the other way around. Manhole cover failed, transferring all load to the other tyre, which exceeded the tarmac load rating, and sank in ;) .
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Re: Manhole cover failure at Lanseria

Unread post by Artfly » Fri Nov 09, 2018 2:31 pm

impending wallet failure for some oke
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Re: Manhole cover failure at Lanseria

Unread post by Wonko the Sane » Fri Nov 09, 2018 3:19 pm

Any photos of the "rescue"?

W
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Re: Manhole cover failure at Lanseria

Unread post by biffvj » Fri Nov 16, 2018 7:27 am

Wonko the Sane wrote:
Fri Nov 09, 2018 3:19 pm
Any photos of the "rescue"?

W
Or photos of the owners face when he heard about it?
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