Cantilevered masonry pier question 1

[WWTEng]

I am currently exploring if a 32"x32" masonry pier (4 wythes of 8" block) cantilevering 26' is a practical idea (architectural element occurring at several locations along the exterior of the building). The pier will of course be grouted solid with #6 or #7 in every cell. It is a non-load bearing element but will see wind. The pier can't be tied back into the building because of thermal break between the pier and the building, so they are standalone elements.

Just as a gut feeling I don't think it's a good idea but I do want to run some numbers to establish an engineer judgment. And the first question I have is regards to h/r ratio for compressive strength. Since this is a cantilever element, should h be 2x26' or 26' still applicable?

Wind is 90 mph and SDC is B.

 

[RFreund]

I can't really answer your questions but I'll add that because its non-load bearing, you will not have overly large P-Delta or p-delta Moments so that is a +1. Also because your full grouted with reinforcement you basically have a concrete section.

EIT

http://www.HowToEngineer.com

 

[msquared48]

I would use 2.1 X 26.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[bpstruct]

It is basically a cantilever beam if I understand your description. Compressive strength is unlikely to be a concern.

 

[hokie66]

Build it in running bond and fill the 16" x 16" void with concrete as you fill the rest of the block. Pea gravel size aggregate.

It is not a column, it is a cantilevered beam.

 

[WWTEng]

Update: The way the arch wanted to set up the pier was to have 3 wythes of 8" block, so solid block was 24"x32". Using wind load case-2 (75% wind in each direction) and also checking for compressive stresses due to self weight (using h=2.1x26' as suggested by M^2), the interaction between flexural stresses in both directions and compressive was a little over unity. So the idea has been nixed. Instead I talked the arch into doing a full height steel column (36' tall) braced to the roof framing.