Point Load on Steel Ledger Angle

[BEFORT]

I have a steel ledger angle (L7x4x1/2) attached to a CMU wall with 3/4" dia expansion anchors at 16" o.c. Steel joists bear on top of the ledger angle and are spaced at 6'-0" o.c. Approxiate DL + roof LL= 3400 lbs.

In order to not exceed the capacity of the anchors, I would need to use 4 anchors over a distance of 4'. Is this acceptable or should the anchors be concentrated at the point the load is applied?

 

[msquared48]

The angle does not need to be continuous here, so placed the bolts at 8" on center in an angle 30" long.

Is the angle LLV? If so, why the 7"? Seems like a 4X4X1/2 could do the job too.

There should be another continuous angle above this one, also bolted to the CMU wall, to catch the diaphragm loads and serve as a chord member.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[asixth]

Does the angle have capacity to transfer the 850lbs 24".

I agree with mike, if the CMU is corefilled then I would be providing an anchor every core (8").

Does the roof have any significant uplift?

 

[BAretired]

If the masonry is not core filled, I would remove masonry at each joist location, provide a concrete bearing pad and anchor the joists to the pad. I would not use an angle at all.

BA

 

[ron9876]

I have always debated this with myself. If you use 4 bolts at 8" c/c is the angle rigid enough to mobilize all the bolts. I don't think so. I would do something so I could use two bolts only under each joist.

 

[BEFORT]

Thank you all for your responses, I had gotten sidetracked and just checked for responses.

I am reviewing structural documents and the condition I have described is what is proposed. I agree with all of your comments. My concern is having to distribute the force over a distance of 4'. In my opinion the anchor below the joist would resist all the load until it failed and then be transferred to the adjacent anchors which would have to fail in order to transfer the load to the last 2 anchors. In other words, the best condition is 2 achors supporting the point load. Bt the way, the angle is LLV.

Make sense?