Hydro-testing thrust block
Hydro-testing thrust block
(OP)
Hi,
I was relocated to a new job site “Pipeline Project Site”, and the first task to handle is” Please check the design of this thrust block!!”
This thrust block is a temporary thrust block that will be used during the hydro-testing of 1600mm Dia DIP, with a pressure of 18.75 BAR. It will be laid against undisturbed trench wall, at depth approx. 3m.
We have the soil factual report and a lot of boreholes & trail pits have been done ( it is a 46km pipeline!yeah!)
MY PROBLEM:
Well, as far as I know, I can ONLY, and ONLY use the criteria of lateral earth pressure (Active & passive) to calculate the needed area of the thrust block. Of course with the addition n of the frictional forces between the pipe/surrounding and the thrust block base along the tested segment of the pipeline.
Is there any other criteria I can follow? Because the size of the thrust block produced from the lateral earth pressure criteria is very large and may not fit in the trench, since is there a lot of neighbor pipes already there.
Can I use the values of the uniaxial compression strength test? I mean divide the thrust force by the area of the thrust block if it is smaller than the UCS value then am in a good shape?
or can use the value of the vertical bearing capacity to calculate the needed thrust block area?
thanks
I was relocated to a new job site “Pipeline Project Site”, and the first task to handle is” Please check the design of this thrust block!!”
This thrust block is a temporary thrust block that will be used during the hydro-testing of 1600mm Dia DIP, with a pressure of 18.75 BAR. It will be laid against undisturbed trench wall, at depth approx. 3m.
We have the soil factual report and a lot of boreholes & trail pits have been done ( it is a 46km pipeline!yeah!)
MY PROBLEM:
Well, as far as I know, I can ONLY, and ONLY use the criteria of lateral earth pressure (Active & passive) to calculate the needed area of the thrust block. Of course with the addition n of the frictional forces between the pipe/surrounding and the thrust block base along the tested segment of the pipeline.
Is there any other criteria I can follow? Because the size of the thrust block produced from the lateral earth pressure criteria is very large and may not fit in the trench, since is there a lot of neighbor pipes already there.
Can I use the values of the uniaxial compression strength test? I mean divide the thrust force by the area of the thrust block if it is smaller than the UCS value then am in a good shape?
or can use the value of the vertical bearing capacity to calculate the needed thrust block area?
thanks





RE: Hydro-testing thrust block
If you don't have space for an adequate thrust block, the booklet also mentions the use of restrained pipe joints as an alternative. What I suggest that you do NOT do is combine restraints such as an undersized thrust block with pipe / soil friction, etc. to reach a theoretical cumulative total restraint that appears to be adequate. That is a recipe for trouble. If the thrust block cannot be sized appropriately, with a satisfactory safety factor, then go with suitable restrained joints to resist all the load.
http://www.dipra.org/app/uploads/Design-Thrust-Res...
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RE: Hydro-testing thrust block
More information concerning soils, and what/where exactly you are dealing with as far as other utilities alongside the pipeline, might help to get better suggestions.