Hey Everybody,

I am doing Stress Analysis for Buried Line app 5km long.

For iteration purpose i provided an Y support in Above ground area i.e. first support in AG at AG/BG transition. But my consultant says its a wrong practise and hence to remove the Y support.

Can anybody help me to understand technically why i cant provide such support.

Also please note its lifting at that node and if given Y it takes load in Ope Case.


Thanks & Best Regards,
PJ

To properly represent your piping system, the Caesar II model should include buried and relevant above ground piping, including all restraints.

For instance, if you are looking at a pipeline end, the model should typically include AG piping to and including the launcher / receiver and any connected piping that might be displaced or otherwise create a load.

The line is modeled from Launcher (having barred tee and modeled till manifold header) to buried consisting of several flange pits to receiver area(having barred tee modeled till scope break).

Hence the AG piping is included there are certain supports provided in AG and the support(simple rest) i.e.. between IJ to AG/BG transition is lifting due to which its going in iteration.

My doubt is why i cant make this simple rest as HOLD DOWN(Y) it solves my iteration issues but shows a positive load in OPE condition.


Thanks & Best Regards,
PCJ

Maybe your consultant evaluated the consequences of "hold down" to the supports of launcher/ other supports.

I agree with Mariog.

If there is an upward force on a support in operation, there must be a (presumably unwanted) downward force elsewhere. Have you checked this out ?

I checked with my consultant, he says there could be a unwanted downward force at other support since its restricted by hold down at some point.

But he says its always a wrong practice in considering a HOLD DOWN for AG supports.

Now my concern is In case, if i dont find unwanted downward force at any other support just a normal sagging or a load which can be taken by rest in such case can i give HOLD DOWN???

Thanks & Best Regards,
PCJ

Do you mean in the actual support of in your Caesar II input ?

If it sees no real load there is no point constructing an upward acting restraint in the field.

If you are just concerned about your model, then you can use a Y restraint fixed both ways. It will save a tiny amount of run time since it is a linear restraint and does not need iteration, as does a one-way restraint.

There is a upward force in the same Y restraint but i cannot figure out where is this (presumably unwanted) downward force elsewhere.

Thanks & Best Regards,
PCJ

Is it a good practise to provide restraint'-Y' when it is lifting? or the support location should be analysed and changed so that there is no lift off in the restraints??.


Thanks & Best Regards,
PCJ