×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Existing Masonry Building - Risk II to Risk IV

Existing Masonry Building - Risk II to Risk IV

Existing Masonry Building - Risk II to Risk IV

(OP)
Similar to SteelPE (or kind of similar), I'm converting an old shopping center into an essential facility. Building was built in 1999.

8" CMU, #5 @ 16" o.c. vertical, #5 @ 48" o.c. horizontal. 25ft tall walls (not sure how they got a 25ft 8" cmu wall to work). CMU is solid grouted, no open cells.

I haven't looked back to the UBC code (which I believe is the code I can use under the Existing Building Code Provisions) but just doing a quick calc my deflection is 3". The limit for this building is 2".

Assuming the UBC doesn't calc out any differently, are there any options to reinforce the walls to reduce the deflection?

The alternative is the contractor tears the building down and builds new. But he wants to know if bringing the existing building up to code is feasible.

RE: Existing Masonry Building - Risk II to Risk IV

If the wall can be made thicker, it could be reinforced with vertical steel beams applied externally and attached to the masonry wall at discrete locations. Alternatively, pneumatically placed mortar with steel reinforcement could be applied to one or both sides of the existing wall. These options are not particularly appealing but neither is tearing it down and building anew.

BA

RE: Existing Masonry Building - Risk II to Risk IV

(OP)
I hadn't contimplated vertical beams. You would basically have the horizontal bars transfer force to the vertical beams?

I'm not familiar at all with pneumatically placed mortar. I have retrofitted masonry that isn't solid grouted...so this is pretty new to me.

RE: Existing Masonry Building - Risk II to Risk IV

If the walls are 25 feet tall, maybe one or two additional floors could be added. Would help support the CMU. Don't know what the client's needs are though.

Mike McCann, PE, SE (WA)


RE: Existing Masonry Building - Risk II to Risk IV

The 8" wall with #5@48" o.c. horizontal could span horizontally between vertical beams if they were spaced at, say 12' centers or less.

Pneumatically placed concrete (Gunite or Shotcrete) has been used quite a lot in the walls of water retaining structures such as in-ground swimming pools and water reservoirs. It would need to be mechanically anchored to the concrete fill in the masonry wall.

See this link:
https://www.google.ca/search?q=gunite&ie=utf-8...

BA

RE: Existing Masonry Building - Risk II to Risk IV

(OP)
I like the additional floors idea. I've done a couple stations that were new builds and they have been only one story. It's a lot of space to heat for this building...about 42,000 sqft. I have no idea what they intend to do with that much area.

RE: Existing Masonry Building - Risk II to Risk IV

As Mike suggested, lateral bracing at mid-height would remove the need to reinforce the wall at all.

Another option would be to use masonry pilasters at about 12' o.c. instead of steel beams.

BA

RE: Existing Masonry Building - Risk II to Risk IV

(OP)
Thanks BA!!!

I will read up on the concrete stuff tonight.

RE: Existing Masonry Building - Risk II to Risk IV

8" CMU at 25' tall ouch. I recently completed a project that had 12" CMU at 26' tall and I said never again.

RE: Existing Masonry Building - Risk II to Risk IV

(OP)
Yeah, 25ft is a bit ridiculous. Someone apparently was able to justify it...or at least say they did.

I think BA's idea of creating a Masonry "Pilaster" at 12ft o.c. is probably the route I will recommend going. On the positive architectural side, it will create some addition texture to the building and make it not look so bland :)

RE: Existing Masonry Building - Risk II to Risk IV

Might have been designed using PCA'S "Slender Wall Design Manual" approach, adapted to CMU... Off the wall, but maybe...

Mike McCann, PE, SE (WA)


Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources