Dear Sir,
I am curious about SCF calculation for tubular connection with ring stiffeners.
It is mentioned that Smedley and Fisher (1991) formula is applied.
The R-factor calculated by using the formula mentioned above looks ok.
However, the final SCFs reported by SACS gave something strange for me.
At the axial saddle location, the numbers are similar to axial crown location which is strange as they have their own SCFs and R-factors.
For example,
the SCF at brace axial saddle should be 2.34 while SACS gave 3.43.
the SCF at chord axial saddle should be 2.41 while SACS gave 2.74.
Can you help to have a look ?
Regards,
Kasiphon
Kasiphon,
I need to check with the developer on this one. I think it may have something to do with how the ratio is applied to the stress which may be causing the problem, but it does look suspicious that the SCF is identical for the cradle and saddle.
Geoff
Hi Geoff
Thank for your response,
Btw, I am waiting for the answer from your developer team
SACS is taking the maximum axial SCF in accordance with API RP 2A Section C5.3.3 stating that maximum saddle and crown values should be applied to the whole brace/chord intersection:
Essentially we are just taking the maximum axial SCF and applying it to both the crown and saddle to ensure that we get the maximum for any given location.
Hi Geoff,
It is clear and thank you very much for your reply.
I have another question.
Refer to API or original paper of Smedley&Fisher, they require different minimum SCF for each location and load type, see picture below.
How can I put in SACS ? Do we have any command for this ?
Currently, I use SCFLM which is applied for all load type and weld location which is not suitable for this requirement.
Answer Verified By: Kasiphon Kurojjanawong
SACS automatically applies the minimum SF limit of 1.5 for all locations and uses a default of 2.5 for the brace axial crown SCF and brace out-of-plane bending SCF in accordance with the original Smedley and Fisher recommendations which is slightly more conservative than the API recommendation. You can override the 2.5 minimum SCF using the SCF Minimum option on the CONRST line (See fatigue manual for CONRST line documentation).