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Bearing Plate Question

Bearing Plate Question

Bearing Plate Question

(OP)
See attached pictures - I am NOT the EOR for this project, but noticed a potential disaster waiting to happen.  I rough calculated the point load from beam reaction to be in the 25-30 kip range from roof load, CMU wall DL, PC Plank DL-LL, no bearing plate installed on the CMU and I believe not grouted below and of course no column below either.  The CMU has slight diagonal crack (maybe not clear on the picture).  I feel this needs to be reported to Owner as a serious concern...thoughts?

RE: Bearing Plate Question

The axial load in the CMU directly below the beam should have been checked for the concentrated load on the wall plus lateral wind (assuming it is exterior).  Usually the end two or three cells are reinforced and fully grouted.  

If there is no rebar or grout in these cells, then yes, you may have a problem here.

 

RE: Bearing Plate Question

(OP)
JAE - I agree and that's my concern.  No grout,no bearing plate to distribute the vertical load from the steel lintel.  I couldn't believe it when I saw it and just wanted to get some feeback.  FYI - it is an interior wall, so only internal pressure laterally.  I posted another closeup of the diagonal cracking.

RE: Bearing Plate Question

Remedial measures indicated.

BA

RE: Bearing Plate Question

I would look at least at a temporary/permanent steel pipe or HSS column outside the CMU, connected to the beam and the load taken to the foundation.  

Another concern, since the lack of a bearing plate, grouting and column reinforcing is a problem, if this beam is also a drag strut, were the tension links, whatever they were, ever installed to the CMU wall?

There could be more problems here than meet the eye.

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

RE: Bearing Plate Question

(OP)
not sure..

RE: Bearing Plate Question

You stated you are not the EOR...well, tell the EOR what you observed.

RE: Bearing Plate Question

Are you 100% sure that there is no bearing plate or the cells are not grouted.  I have seen this type of cracking before.  In my instance, I think it was due to the fact that the lintel was welded to the bearing plate.  I think this provided to much restraint which caused a crack similar to the one shown in your pictures.  In the end we switched the detail around to gain some more flexibility while still maintaining a good connection to the masonry.  Once we made the switch the cracking went away.

RE: Bearing Plate Question

(OP)
Hokie, yes, we have alerted the EOR and he/she is reviewing the condition.  And yes, I am certain there are no bearing plates for the majority of steel lintel bearing locations.  The CM and steel erector both questioned the EOR prior to my site inspection and confirmed that he/she did NOT intend to have bearing plates.  The steel erector mentioned this is the first project he has erected without bearing plates on lintels other than door heads spanning 3 +/- feet.   

RE: Bearing Plate Question

So what role do you play in this project?

RE: Bearing Plate Question

(OP)
Steel Inspector.

RE: Bearing Plate Question

I would write a letter to the EOR outlining your concerns.  This puts the monkey on the EOR's back and should compel them to at least review what they did.  If they do their job - check it and find it's OK then all's well.  If they do their job and check it and find that there's a problem then all's well.  If they don't do their job and don't check it - you've at least covered yourself and put the onus on the EOR.

 

RE: Bearing Plate Question

I agree with JAE's approach and have used it before. You have to put the ball in the EOR's court and give them a shot and fixing the problem. But you also may want to do a follow up in case the EOR ends up just trying to sweep the problem under the rug. I had an odd encounter once where it seemed the EOR was trying to talk ME into their part of the structure being ok, as if they were not sure and to me it was very obviously unstable (I was the specialty engineer doing the light gage steel stud). I stood my ground and they added bracing...

RE: Bearing Plate Question

You have done what you need to do by contacting the EOR.  There may not be a problem--I have designed many lintels without bearing plates.  The 9th Edition of the AISC Manual has a method for checking the bottom flange of the beam without a bearing plate.

DaveAtkins

RE: Bearing Plate Question

Is there a return wall? How long is it?

RE: Bearing Plate Question

Looks like a decently wide flange and 12" +/- bearing.  Depending on the flange thickness, you may be ok with no bearing plate.  The lack of grout/reinf. in the cmu is the bigger issue.  You would almost certainly need solid grout beneath the beam...

RE: Bearing Plate Question

(OP)
Dave - I am not overly concerned with the steel member, it is the CMU below and the potential for catestrophic failure should the CMU web/shell let go.  Without a bearing plate and grouted cores to distribute the load, I believe a problem exists.

RE: Bearing Plate Question

(OP)
There is no return wall, this is the end of an 8" wall, basically an opening in an interior wall.

RE: Bearing Plate Question

Drill a small hole through the face shell to confirm the presence or absence of concrete fill.  If absent, shore beam and remedy the problem.

BA

RE: Bearing Plate Question

Whether there is grout or not, the cracking is sufficient reason to require rectification.  As structural steel inspector, notifying the EOR and including the bearing issue in your report is your responsibility.  What happens next is out of your control.

RE: Bearing Plate Question

I was thinking more about this (I know that's dangerous), and it occurred to me that this could also be a problem with shrinkage in the CMU, or temperature in the steel beam, creating a tension force into the wall that was not tied back into the wall with "U" bars or hooked bars.  If this was not a drag strut, then slotted holes in the beam flange should have been provided to alleviate this condition.

As for the grouting, the pitch of the sound a hammer struck against the CMU cells will tell if they are grouted or not.

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

RE: Bearing Plate Question

It looks like a bad detail to me.  I typically weld the plate to the bottom of the lintel beam and extend the plate over the full bearing length on the masonry.  This eliminates the need for a separate bearing plate.  I also call for the cells below the bearing to filled with grout continuously to the footing.  By calling for vertical reinforcing below the bearing point, it is more likely that the grout gets put in.

Adam Vakiener, P.E.

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