×
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

Concrete Frame with Masonry Block Infill

Concrete Frame with Masonry Block Infill

Concrete Frame with Masonry Block Infill

(OP)
Hi,

I have a three storey structure with the primary load resisting system being a reinforced concrete frame. I do have masonry infill and herein lies the question.

At exterior wall locations, how do I detail the masonry wall connection to the R/C beams such that it can transfer wind loads to the upper and lower beams but does not transfer gravity loads to the frame below.

The architect is also concerned about the hairline crack that will develop between the wall and the beam.

Any comments?

Thanks

RE: Concrete Frame with Masonry Block Infill

I'd limit the deflection of the concrete beam to L/600 and tell the architect to design a window or something.
Has he seen cracks in masonry due to deflection of concrete beams?

RE: Concrete Frame with Masonry Block Infill

Use head restraint ties.

RE: Concrete Frame with Masonry Block Infill

Tomfh,
Can you little more elaborate on head restraint ties? Are there any commercial brands? Can they be fabricated on site?

Clefcon

RE: Concrete Frame with Masonry Block Infill

These connectors will form a working joint on the exterior face of the building. This may create a waterproofing problem and will crack finishes.

In most concrete buildings the majority of gravity loads are the self weight of the structure itself therefore the majority of the deflection occurs before the infill walls are placed. I have always made a hard connection to the beam above and require that the connection not be placed until all shoring/reshoring has been removed. This will allow for load transfer thru the walls in accordance with stiffness. This detail has been used in south florida for years and I am not aware of there ever being a problem.

The conection can consist of threaded dowels into form savers, embed plates in the concrete beam with a plate welded after forms are removed, dovetail anchors, epoxy dowels, etc.

We do lots of condos with p/t slabs. Same question with infill exterior masonry walls. PVC sleeves are placed thru slabs to allow for vertical reinforcement to continue thru the slabs. As far as I know everyone uses this detail without problems and in this instance the edge of a slab isn't nearly as stiff as an edge concrete beam.

Fortunately concrete is a very forgiving material and it will redistribute loads whenever possible if it is overstressed.

RE: Concrete Frame with Masonry Block Infill

(OP)
Thanks Ron,

I do, and I'm sure the architect will share the concern about the waterproofing and cracking issues with the use of the wall restraints.

Ataman

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