I have some steel Intermediate Moment Frames (IMF) that I'm designing the moment connection for. I've run a Smart DW connection in both version 13.4 and 13.5. Version 13.4 appears to correctly calculate the panel zone shear in accordance with AISC 341-16 Section E2.6e. Version 13.5 appears to incorrectly include the plastic moment strength of the attached beams for both IMF and SMF where it should only consider Mp for SMFs. Has this been corrected in 13.6 or 13.7 (I didn't see it listed in the resolved issues).
I see that a couple of work items have been completed that relate to the IMF requirements (e.g. 567995 IMF Panel Zone check uses incorrect demand, same as SMF based on RBS plastic hinge rather than beam end moments). I'm not seeing the version that it was released in however. If you want to send in your file I can run it on the latest version and send back the output.
Answer Verified By: Gumpmaster
Thanks Seth. That sounds like exactly my issue. We still have a computer on 13.4, so we'll just stick with that one for this building until my company rolls out 13.6.
I took a second look at the referenced work item, but there was not actually a change made. The note indicates that it's working as designed and says, "RAM Connection seismic provisions follows “Prequalified Connections for Special and Intermediate Steel Moment Frames for Seismic Applications”, where are described the design requirements for the mentioned frames (Table 2.1.). The user model, configured as a reduced beam section, follows Chapter 5 provisions. Where specifically in Step 5 is described the calculation that RAM Connection follow for both frame systems. The application is working as it was designed." Let me know if that does not sound correct to you.
Gumpmaster's issue sounds like the same issue I reported in version 13.03.00.33 for WUF-W IMF connections back in October 2020... I thought that had been corrected in the next release. Is it back again?
I believe it is back again for 13.05. It was apparently fixed temporarily in 13.04.
The issue is that IMF connections do not require the plastic moment capacity of the beam applied for panel zone calculations while SMF connections do. The program apparently applies the plastic moment to both types of connections.
Yep, same issue I reported in 2020. Although at the time, it was actually using the input design moments for determining the beam flange forces and the need for column stiffener plates, while using the beam capacity for determining column PZS, so it was saying web doublers were needed when they weren't, but also saying no stiffeners were needed or smaller ones than what were needed - exactly the opposite of what was needed. Mine were WUF-W connections, which also had the wrong Cpr factor hard-coded into the program. By the time Bentley got it fixed, I'd developed my own Mathcad-style calc since I had a project with 32 multistory IMF frames and at least a hundred individual joints that couldn't wait. Don't see IMF's much, but I'm glad I did that if the error came back in RAM Connection.
Confirmed, we were considering Mp for IMF and SMF. The problem was fixed internally and now only SMF seismic frame use Mp. The IMF now use proper demands based on load combinations not including amplification. This is fixed and will be released in a patch in a month.