Hi, I have run my model and I am getting failures of some members. When I checked them, I found out the ratios below. Then I run it again because I thought something is wrong, but I get the same result.
I always thought that the unity ratio is the Actual stress divided by Allowable stress, but here somehow those numbers give a result of 100.05. Can someone please explain why?
Thank you in advance.
Agata
Look at your member. It is 3 cm dia with 3 m long. This is unrealistic shape. It already exceeds Euler buckling load (See the 1st line of your picture). Go to POST manual, search for "100", you will see the reason.
Hi Kasiphon,
Thank you for your answer, I really appreciate it.
The element in subject is indeed a 3m long steel rod of a 3cm diameter, it is a hanger support. I released its ends and I indicated that it should be tension only member, so I did not expect to see compression and buckling in the results. Is there another way to indicate tension only element, not to have compression included in the analysis? I will appreciate your reply.
When you define Tension only/Compression only, you need to run with Gap Analysis. It cannot be calculated with normal static analysis.
See the option in SACS executive, pick with correct subtype analysis which should be Static Analysis with Gap element NOT Basic static analysis.
If you pick wrong subtype analysis option, Tension only that you defined will be ignored.