Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

CMU Wall Strengthening

[Subject Prev][Subject Next][Thread Prev][Thread Next]
I have a shipping warehouse that has some problems with its masonry
bearing wall.  The front of the building has 3 overhead door openings. 
The wall is 12 inches thick, 8" CMU and 4" brick.  The doors are 12 feet
wide.  Two doors have a loading dock bumper height of about 3 feet high. 
A third door opens on grade and is 14 feet high.  All door heads are same
height.  The masonry pier between doors is 5 feet wide.  The remaining
front of the building is a full height masonry wall for about 100 feet in
length.  The wall height above the doors is about 9'-8".

It appears that a truck has caught the side of the tall opening.  The
masonry piers are out of plumb.  I dropped a plumb bob from the roof to
the door head and the top of door head is about 3/4" out of plumb to the
exterior face.  I dropped the plumb bob from the door head down to the
ground and the wall went back in about 3/4".  The adjacent door was
similar, slightly less.  The pier between the last 2 doors was about 1/2"
out of plumb, same curvature as the first one.  As I progress away from
the 14' high opening the out of plumb decrease, so it appears to radiate
from this one door.  That's why I think a truck must have pulled out one
door jamb.  The top of this jamb has severely cracked brick.

My fix first is to repair the cracked brick.  The steel lintel above the
door bears 8" on the jamb, the first 4" being on the cracked brick.  Then
I think I should stabilize the masonry piers.  My thought is to use a
steel 'strongback' on the inside face.  I envision a steel wide flange
column bolted to the CMU wall.  I expect the top course to be a bond beam
since steel bar joist bear on it.  I can attach the bottom to the
concrete floor or a concrete wall at the base.  I would guess I could
connect to the masonry wall at about 2' o.c. vert. with adhesive anchors.

I want to get some feedback on what to design this 'strongback' for. 
Perhaps some of you have done this before.  The strongback will not be as
stiff as the CMU wall so I don't believe it will take the lateral
loading.  I guess it would just be for buckling stabilization so the wall
does not get worse.  What kind of forces would this be?  Would one
strongback per 5' wide pier be enough?

Thanks for your help.  I really appreciate all the wisdom from your
input!

Rich

________________________________________________________________
The best thing to hit the internet in years - Juno SpeedBand!
Surf the web up to FIVE TIMES FASTER!
Only $14.95/ month - visit www.juno.com to sign up today!

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ********