hi, I have some questions about the connections design procedure and detailing by RCSA.
I) Does the "RAM connection" really use of "AISC 358-16" code provisions?
for example, recently I have checked a bolted flange plate connection and noticed that RCSA is using FEMA350 instead of AISC 358.
As you know, BCF from 2010 became a "prequalified connection" with a specific design procedure. (but FEMA has been published in 2000.)
II) when we design an RBS connection, in the 3D view, the weld access hole seems has the special form in accordance with "AWS D1.8 (=alternate geometry)", but in DXF view it has regular rectangle form? (like AWS D1.1)
III) Why in "stiffened seated connection" some bolt and weld doesn't show?AISC construction manual asserts that the beam must be connected to the seat plate with an erection bolt. furthermore, the seat plate should be welded to the stiffener with a minimum size of the double fillet weld.
IV) also in "stiffened seated connection", why doesn't RAM connection check the capability of the stiffener to resist against the compression stress?Most design books - based on AISC360 - suggest that:-the plate should be compacted to prevent local buckling.-the plate thickness must be adequate to develop the fillet welds capacity.-also, the stiffener must be checked for bearing on the contact area. ( with/without load eccentricity)
IV) It seems that some provisions of professional detailing do not exist in double angle connections.for example, I inferred from AWS D1.1 2.9.3.2 that horizontal welds of angles to the beam web should be terminated before the edge of the web. but in ram connection, these welds are continuous to the end of the beam.
Thank you for your time and consideration...
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Hi, in addition to my "still-unanswered questions!!", today I observed, in the "bolted flange connection" the location of continuity plates is wrong. they should be continued along the cover plate. but RCSA draws them at the level of beam flanges.anybody can explain this to me? what is the reason?
On the first point, the current status of the prequalified connections is as follows:
AISC 358
FEMA
The 341-16 was not fully documented when we did the update to the 2016 codes and the specification was released later so our implementation is partial. We have both moving the Flange Plate to 358 and complete the AISC 341-16 planned for next release Q4.
We are still reviewing the other questions.
Seth Guthrie said:We are still reviewing the other questions.
Hello Seth, I understand you are very busy, but I would appreciate if you could let me know what are the results of reviewing.thank you...
I have confirmation from the product manager on your various points.
This is a bug, if the seismic provisions is activated and the framing system defined as IMF or SMF, then ASW D1.8 alternate geometry should be used. DXF will be fixed in next release.
III) Why in "stiffened seated connection" some bolt and weld doesn't show? AISC construction manual asserts that the beam must be connected to the seat plate with an erection bolt. furthermore, the seat plate should be welded to the stiffener with a minimum size of the double fillet weld.
Since this elements does not have any effect on design, we are not drawing it, but we will add it as an enhancement for next release (2019 Q1) to give a better reference for the connection.
IV) also in "stiffened seated connection", why doesn't RAM connection check the capability of the stiffener to resist against the compression stress? Most design books - based on AISC360 - suggest that: -the plate should be compacted to prevent local buckling. -the plate thickness must be adequate to develop the fillet welds capacity. -also, the stiffener must be checked for bearing on the contact area. ( with/without load eccentricity)
We are not doing any checks for the stiffener thickness. We will add it on next release (mid-November). However the beam local yielding and web crippling are checking the W dimension of the stiffener, and the bearing is being checked on the Stiffener top side bearing capacity
IV) It seems that some provisions of professional detailing do not exist in double angle connections. for example, I inferred from AWS D1.1 2.9.3.2 that horizontal welds of angles to the beam web should be terminated before the edge of the web. but in ram connection, these welds are continuous to the end of the beam.
We are considering welds to go from edge to edge, the AISC it is not clear in this aspect, and we have sent an inquiry for the best way to proceed. As soon as we have a answer we will plan an enhancement to make this “mill underrun” available for users.
V) Concerning the continuity plates location.
Yes continuity plates should be located at the level of the flange plates, this will be fixed for mid-Nov release.