C2 with Negative Code

Estimated

Analyzing a particular model, the C2 delivers me negative values in some nodes in cases of load OCC, nevertheless these values in spite of the fact that they are negative, estan far below of the maximum effort of the tracing.

Consults: These values indicate that it trumps the tracing, it is a mistake of C2 or cases of load.

Because they give negatives

Thank you

Er, um .....

Have you missed out some information here ? Are you modelling piping and tracing ?

i Have negative number in code compilance output.

I have seen this before in B31.8, which as you know now uses the liberal allowable for checking EXP stress. This means that it subtracts Sl (SUS) from the allowable. If you have neglected to input Sc or Sh then Caesar II interprets these as zero and subtracting Sl from this will then yield a negative allowable stress. It also might happen if Sl is much higher than Sh (your SUS stress is failing). This won't happen in B31.1 or B31.3 because those codes state that if Sl is above Sh then you should not use the "liberal allowable" equation, but instead revert to the more conservative equation for the EXP allowable. B31.8 has neglected to make a similar statement.

There is a second way you can get a negative allowable and that is if you use an Algebraic combination method for adding two load cases together. If you do this for an OCC case Caesar II will stop you, but if you called the load case SUS, OPE, or EXP then you could have this problem. When you are adding load cases, you should use either Scalar or Absolute combination methods.

If either of the above explanations don't solve your problem then please send your model to techsupport@coade.com and we will help you further.