Not such a nice office view tonight - Night survey of earthquake damaged sewers.
Sorry about the image quality of the camera in my phone.
The first view the public get of us
Which is actually a truck mounted crash attenuator
The crew work up ahead
This is what we are looking at - position and level to within 0.010m - yuk
All done, marked up, ready for the lid, move on...
You know it struck me last night that I think I'm destined to be a road cone.
Jim,
we do a lot of sewage surveying here, but never did it at night, and never because of an earthquake.
It must be a very busy road since you have to work at night I guess.
The square cover looks a heavy one.
Who owns the sewage in New-Zealand? They started leasing them here some years ago, before it was the cities that owned them.
Do they have people too on site to open and to keep it safe or does the survey crew take care of that.
Any idea of the results yet, how did they move? And what to use as reference points after an earthquake??
Thanks for sharing,
Christof.
The sewers are owned by the city. We do night work on the roads too busy to do safely during the day.
We use a contractor to supply the safety truck and driver. We do the opening, but if stuck, sealed over or full of yuk we call just call it in, and we are told to go back when the pit is ready for us.
The results are all over the place. The earthquakes have given maximum lateral displacements of up to 2m, vertical of about 0.5m. But it really varies depending on the underlying geology. The old maxim of "build your house on rock, not on sand" really does apply here. We are seeing a lot of liquifaction effects where the land subsides leaving the manholes sticking up out of the roads. We are also seeing general sinking so that sewers that used to flow are now stagnant or flowing backwards.
Each pit is referenced to our own control network of benchmarks, put in with GPS and then precise leveled to give heights. Our network is tied into one citywide that was established after the quakes. That in turn is tied in to our national network. It is all still moving a little - but the NZ survey system is designed to cope with that. It does not rely on fixed coordinates
Christof noted the square cover looks heavy, which they do. They also look like they would be tough to open. Almost all the MH lids here in NY are round, which helps keep them from falling in the hole or getting stuck. Do you know why they use a square lid instead of a round one?
Hope your post quake problems are minimal.
Ken
> Christof noted the square cover looks heavy, which they do. They also look like they would be tough to open. Almost all the MH lids here in NY are round, which helps keep them from falling in the hole or getting stuck. Do you know why they use a square lid instead of a round one?
>
> Hope your post quake problems are minimal.
>
> Ken
Ditto. Square mh covers are a pia. You have to be careful when taking them off or putting them back on. They willl fall down in the mh if not careful. Rare, but I've seen them in the states.
The truck in those pics looks like a Toyota or Nissan maybe? Can you post of pic of the box setup in the back?
N10,000, E7,000, Z100.00
PLS - IL, MO, AR, KS, MN, KY
In Belgium we have both types,
you'll find the square ones mostly in the roads and sidewalks where they used prefab concrete tiles or cobble stones. And the older the covers the more you'll find the square ones, never liked them, it takes two man to open them, they're stuck often and they easily break!
Chr.