Masonry Wall - Pilaster 2

[DJYork]

I am designing a masonry dumpster enclosure 50x20x10 (tall). Is there a rule of thumb about pilaster placement on the wall? Is there a reason to use pilasters instead of designing a cantilever wall? Thanks in advance for the help.

 

[SperlingPE]

Pilasters allow you to design to design the wall to span horizontally. Horizontal reinforcing will be required. I am not aware of any rule of thumb. Reinforcing required horizontally will depend on the placement of the pilasters. Pay attention to vertical reinforcing at the pilaster and foundations for the pilaster.

 

[jike]

I would use 12" CMU with vertical reinforcement. Add extra vertical bars at the opening in case they decide to add a door either now or in the future.

I see no need for pilasters unless the particular code that you are dealing with requires pilasters.

 

[DJYork]

No, it is not in the code, but was wondering the benefit (if any) of designing using pilasters.

 

[UcfSE]

SperlingPE hit it right on: the pilasters will take the wind load and the masonry between will span horizontally between pilasters. If you want them to span vertically you will need a bond beam at the top of the wall to pick up the load from the masonry and transfer it to the pilaster. The advantage is with pilasters you will probably use less total steel. Pilasters are often deeper in section than the wall so you get more moment capacity out of given reinforcement. The disadvantage is that they will stick out of the wall (some architects don't like that). Also, there are more details to coordinate and more engineering to be done. It's probably just as easy to let the wall cantilever, 10 feet isn't too bad. I don't know of any rules of thumb per se, but rather spacing of your pilasters will depend on what kind of reinforcing you want (or don't want) for the masonry infill between. For instance, if you want horizontal bars at 48" o.c. then your pilasters have a maximum distance between them that will allow this. If you find you are needing bars every 16" then maybe you should move the pilasters closer together.