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Associate

Join Date: Jan 2010
Location: pipe line project - KSA ( welding inspector - CSWIP 3.1)
Posts: 29

### Maximum Depth Of The Trench In Pipe Line Project

05/22/2012 9:45 AM

We have a pipe line project ( 80" dia - 9.5 mm thick - X52) and we forced to put the pipe about 14 meter depth.

Is it safe for the pipe regarding to the external load, and how can i calculate the external load and how can i know if the pipe can carry this load or not.

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Guru

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing. Kettle's on.
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#1

### Re: Maximum Depth Of The Trench In Pipe Line Project

05/22/2012 9:54 AM

What is the temperature and pressure in the pipe and what is the material it is carrying?

Please also describe the route of the pipe in the vertical plane relative to some fixed place, such as its inlet or its outlet.

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Associate

Join Date: Jan 2010
Location: pipe line project - KSA ( welding inspector - CSWIP 3.1)
Posts: 29
#2

### Re: Maximum Depth Of The Trench In Pipe Line Project

05/22/2012 9:56 AM

it buried water pipe line so the temp less than 30 c and the pressure is 6 bar

Anonymous Poster #1
#3

### Re: Maximum Depth Of The Trench In Pipe Line Project

05/22/2012 10:02 AM

One way is to telephone the pipe supplier.

Guru

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing. Kettle's on.
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#4

### Re: Maximum Depth Of The Trench In Pipe Line Project

05/22/2012 10:09 AM

As far as liability goes, that rests with the body doing the forcing. Now.

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#5

### Re: Maximum Depth Of The Trench In Pipe Line Project

05/22/2012 11:40 AM

This requires the attention of the responsible engineer on the project.

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Join Date: Mar 2007
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#6

### Re: Maximum Depth Of The Trench In Pipe Line Project

05/22/2012 1:01 PM
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Join Date: May 2009
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#10

### Re: Maximum Depth Of The Trench In Pipe Line Project

05/23/2012 1:38 PM

Good find SolarEagle! GA from me!

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Guru

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#7

### Re: Maximum Depth Of The Trench In Pipe Line Project

05/22/2012 11:03 PM

There are going to be several factors involved in determining the safe load capacity of the pipe:

1. Pipe material type and strength class.

2. Maximum Working (Internal) water pressure, or maximum Hydrostatic Testing Pressure; the maximum of these governs.

3. Maximum Water Temperature.

4. Pipe bedding zone material type, configuration, and trench width at the top of this zone.

5. Pipe zone backfill material type, configuration, and trench width at the top of this zone.

6. pipe trench width, depth, backfill material, and compacted material density above the pipe backfill zone.

7. Maximum Service loads at the surface, such as highway or railway live loads typically.

The Engineer of Record (EOR) should have done the necessary calculations during the project design phase and prior to the Submission of Bidders.

If this is a field change requiring the Contractor install the water main deeper, then it is the Contractor's responsibility to immediately notify the EOR in written for a design recheck to ascertain whether it is safe to do so or not. I have no knowledge of the contents of the Project Manual that you're using there, so I am going on what is normally done here in the USA generally using the ASCE/Engineer's Joint Council boiler plate language, as well as standard practice.

What is the water main material type and strength class? I have no idea what X52 represents as whatever it is we don't use that here. Looking at the 9.5 mm thickness information that you supplied I'm assuming it's a welded steel pipe; probably spiral weld type specifically.

Regardless of the pipe type (be it ductile iron, PVC, Steel, or RCP), there are design handbooks published by the various pipe manufacturing associations, where the design/analysis calculations and load tables are presented.

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#8

### Re: Maximum Depth Of The Trench In Pipe Line Project

05/22/2012 11:56 PM

It is water pipe line? Is it for domestic use? Or Waste water? Why you need to take this much depth? Did you check with the local codes & standards? Please check with reputed local consultants who are familiar with the local codes.

Guru

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#9

### Re: Maximum Depth Of The Trench In Pipe Line Project

05/23/2012 12:29 PM

I worked for St Gobain Pipelines, if using their products they were more than happy to do the calculations. So contact your supplier.

14M seems a ridiculous depth the go to.

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