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One more follow-up: I sent my question to SJI and they responded - here is how they explain it: "Now, you describe a model in which the open web steel joist is not simply supported, but instead, is supported at both ends by pinned supports which are fully restrained from translating in any...

I thought I would post an update. I could not get my head around the magnitude of lateral force I was seeing in my model at the end of the joist versus our collective experience regarding the lack of historical issues related to lateral forces at the joist seats. I felt there must be something...

The chord force determined from M/d is zero at the end of the span and maximum at the center. Since a joist is a truss - each segment between diagonals has a different axial load depending on the moment at that segment of the joist. The axial shortening (delta) of each chord segment can be...

Thanks for the reference. Odd that the author states strain compatibility must be met - yet ignores strain compatibility of the joist chords themselves. The connector between the joists on opposite sides of the beams would need to transfer the diaphragm chord force plus the tension force...

Agreed - on both points.

Thanks for your reply. I made a 2D model of an LH joist to convince myself I wasn't crazy. The axial end reaction is there if the top chord is not free to slide. If the joists are all bearing on steel framing, and offset 12", then there will be small in plane moments in the beam flange - but...

SJI recommends minimum seat welds which are routinely checked when seats must transfer external loads into the joist chords. But what about internal forces? For a building with multiple bays of joists (assume equal spans and loads) with joists on each side of the supports, the column...

The mason actually prefers it as it cuts down time to locate and set bearing plates, one plate for two joists (over 600 joists to set on the job). There are also other project restrictions that force this approach. We are constructing a three story building inside an older historic shell. I am...

I managed to dig up the old detail I had originally followed. It called for 3 1/2" face shells for the 12" block but the thickest face shell I can find is only 2 1/2"..

Thank you. The ties I was considering were to wrap the top and bottom bars in the 12" block section. The vertical bars are spaced too far apart and are also in the center of the wall, so tying them is of little benefit to my point of concern.

A few clarifications: the 1/2" SJI criteria is the maximum distance the bearing plate can be inset from the face of the CMU. There is no restriction regarding extension beyond the face of the CMU, but I agree that a long extension creates even higher stress on the face shell - which is what I...

Thanks to everyone who commented here. I have used a similar detail in the past but only with wood trusses. I am considering using this for long span trusses with a higher end reaction. I have attached the detail I am considering. As the centroid of the reaction for LH joists is 2" from the...

I have seen a joist manufacturer recommend stacking two courses of 12" concrete block (bond beam on top with lintel course below) on top of an 8" CMU bearing wall to obtain sufficient wall width to allow joists on either side of the wall to be butted together, in order to make the joist spacing...

Thank you for all of your insights. I like the strut and tie approach since the steel in the top of the wall will act as a suitable tie, giving me greater capacity than the shear strength of the concrete alone supplies. However, that doesn't help me if the plan reviewer insists this is a post...

Thanks bones - the problem is the contractor already poured the walls without the anchors in place (didn't install the hold-downs for the shear walls either) - so now I'm stuck trying to fix it. I would happily be that vindictive if that contractor had to do the repair at his expense, but he is...

I have read the structural forums on this site for many years and found many an answer to my own questions. However I now have one which has not been addressed before. I am wrestling with trying to anchor a shear wall into the top of a narrow foundation wall. Because of the limited width, I...