Structural Engineering Problem - F150online Forums


Structural Engineering Problem

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  #1  
Old 10-12-2009, 06:15 PM
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Structural Engineering Problem

Ok, I have an sturctural engineering problem I am working on and I thought I would ask you folks for your opinons and procedures:

The problem. I need to jack/push a 8' pipe thru a wall aproximately 20' thick. The wall is made up of 4 arches, two stacked over two and the pipe needs to pass thru the bottom two. The bottom two is filled with rubble, the top are hollow. We can't have any movement of the structure. We do not want to lose alot of the rubble fill during the pipe installation, except for the pipe volume, even though the rubble is not belived to be structural. We are going to grout the rubble voids in the bottom two arches prior to pushing the pipe, but there is no backpressure, so there is no way to know if the entire rubble in the area of the pipe push is completely grouted.

I was thinking of drilling and pushing consecutively larger pipes, maybe 2' first, then a 4', then 6' then 8', each time either pushing the previous pipe out, or cutting it out , as the larger pipe takes it's place.

Do you engineers on here have any better methods for doing this? I am open fo any ideas.

Thanks
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Old 10-12-2009, 06:21 PM
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I think you're getting ' confused with "...
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Old 10-12-2009, 06:41 PM
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An 8 foot diameter pipe or 8 feet long?

And... Your description is a bit confusing....

Can you duplicate this in ms paint

What is rubble? Rock? Sand? Left over building materials? Water? Golf *****?

8 foot diameter pipe you could walk through.

20 Foot thick wall? What is this a bomb shelter?
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Old 10-12-2009, 07:46 PM
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Ok

8' diameter pipe going thru the wall. The wall is 20' thick. Rubble is loose construction debris, concrete brick ect. This is an aqueduct (in the top 2 arches) and thats how they built them back in 1900. Theres a road on top.

Sorry, can't use paint that well.
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Old 10-12-2009, 08:27 PM
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srfdude44- you are confusing as hell.
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Old 10-12-2009, 08:33 PM
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Can't decribe it any better, guess I'm on my own. Thanks anyway.
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Old 10-12-2009, 09:06 PM
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Quote:
Originally Posted by srfd44 View Post
Can't decribe it any better, guess I'm on my own. Thanks anyway.
Can you draw it up on paper, scan it to a jpg and post it here?
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Old 10-12-2009, 09:09 PM
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Just do an image search on the web and post one up. I looked, but couldn't find anything that looks like your description.
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Old 10-12-2009, 10:00 PM
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You realize that 8' = 8 FEET right?? Not inches?
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Old 10-12-2009, 10:09 PM
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you know anything about jack and bore? would something like this work?

i can see 20' wide making one narrow roadway. this pipe for storm drain or sewer?
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Old 10-12-2009, 11:00 PM
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I understand the picture you've painted...i think. Does the job site allow you to pressure inject a concrete slurry on the exterior side walls of the arches? If you could, then inject, wait for 28 days or whatever the mud requires and then bore the middle. I'd also look at sleeving the outside walls where the pipe is to run thru the structural part of the arch wall on both ends and then run the drainage pipe thru that, weld it, and call it good. I would think a 12-18" deep sleeve would be enough. Obviously the sleeve is going to be the structural part that would be grouted as soon as the sleeves are in place, then the boring would continue thru the rip rap. Kapech?
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Old 10-12-2009, 11:04 PM
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i think srfd44's scenario is something like this:

(there will be two more arches stacked on top of the bottom ones, for a total of 4 arches, 2 wide by 2 high)


from what i gather the bottom two arches are filled with crap like brick, concrete, rock, etc. he plans to seal off the bottom two arches and only leave the top two open (for backup water flow)

in between the bottom two arches he plans to put a 8 FOOT DIAMETER (am i right?) pipe for water flow. the depth this pipe needs to go is 20 FEET to come out the other side. (sounds like a bridge)

i think i nailed it all right.
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Old 10-13-2009, 07:06 AM
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02SC4x4

That picture is right on with two more arches over it. Your desciption of the problem is dead nailed on. Guess 8 feet diamater pipe has confused alot of people, but that is correct. The pipe needs to flow alot of water.

Labnard, we will inject slury inside the arches to consolidate the rubble (and seal off any water that may be trapped inside), but there is no backpressure. When do you stop to and ensure the entire pipe penatration area is completely sealed. We may have to guess on this one and hope for the best.

Jack and bore will be used after rubble consolidation, with the boring part being men inside the pipe moving the debris. If the rubble is not too cosolidated, this could mean trouble. That is why I like the step process metioned in the intial post.

Keep in mind this is a Hundread year aqueduct, so it needs to not move during this operation.

Thanks
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