soil caracteristic

[avavluv]

Hi everyone First I have to mention that I am not a native english speaker Am a mechanical engineer actually working on a. piping system that cntain buried piping.That why we need some soil caracteristics such as density, internal friction angle and soil cohesion. As a reference document document we received the geotechnical repory which contains soil density for 2 sites only ( our piping systems are in three different sites) but doens't contains cohesion neither internal friction angle. For flexibility analysis we took those values from CODETI but to dimension underground support structures we cannot use those values. My question is the following is there a paragraph our a text in the EUROCODE that gives typical values of these carateristics for each soil type or even formula to calculate them. Or we can only determine them by. S field or laboratory test. ? Thank you in advance

 

[BigInch]

There are standard values published in many reference textbooks. the problem is that soils on any typical site are not composed of the standard soils and you wind up taking on additional risk that should had been eliminated by a proper soil analysis. Get your consultant to do that work. Pay him extra to do it if that information was not asked for as part of the original contract's scope of work.

 

[avavluv]

BigInch,
thank you for your reply, the problem here is that we don't have a direct contact with the consultant but our client does and. It fiesn't seems that he is going pay him extra and ask him for addional work we gonna try any way, you said that there are standard values pubished in many reference textbooks do you have any idea where in the. EUROCODE (If exist) I can find those values or in any other standard covered by the. EUROCODE

 

[BigInch]

Tell your client that you cannot do your job without that information. If you have to continue along that course, then you may be have to pay the consultant, or another one, to provide it for you so that you can complete your contract obligations.

Codes do not provide design values, only minimum design requirements.
FYI

http://www.geotechdata.info/parameter/angle-of-friction.html

 

[KevinNZ]

The geotechnical report for the two sites have may all the information you need, It just needs to converted from the reported values to the parameters you need, Civil engineers will know this. (I keep my calculations to nice well defined steel)

The third site is problem. The client needs to tell you what to use. Or you can run your design with a whole range of soil conditions that may on the site and see if this effects the piping design, then go with a conservative piping design the works in all cases.

 

[SNORGY]

Have to agree with KevinNZ here.

There are frequent situations in which clients, for whatever reason, either marginalize the importance of or fail to understand the reason why an engineer designing something that you plan to put in the ground would want to know about the ground you are planning to put it into but, sadly, all too often, they simply don't want to spend the nominal amount of money it would take to come up with that readily-obtainable answer. So, you end up "envelope engineering" stuff and picking the worst case that satisfactory addresses all of the "IF-THEN-ELSE" loops.

What it comes down to is this. Straight, well defined questions get straight, well defined answers. The more vague the problem definition, then the wider and more ambiguous becomes the engineered response. Often, that's the corner you get painted into when you are the individual being tasked as the one in charge of "solving the problem".

I even had a client once who told me to satisfactorily solve a stress analysis problem involving pipelines and risers given the following simultaneous constraints:

(1) There is no geotechnical information and there will be no geotechnical evaluation performed to obtain any.
(2) Displacement of riser piping above grade is unacceptable.
(3) Any forces and moments imposed on riser supports are unacceptable.

Sometimes you just can't fix stupid, but irrespective, if there is a way to evaluate and present options given the information at hand, it might be better to take that approach than it is to simply out-and-out refuse to perform any work until you get the information.

 

[BigInch]

You simply tell the client that he does not need an engineer to do that, so he is perfactly free to do it himself any which way he likes.