Masonry Chimney

[JoeBaseplate]

I have been asked if I can design a chimney that is to replace an old existing one. The height above roof line is 25’. I have never designed a masonry chimney before and feel a little reluctant to take on the task but I am also curious to know how it’s done. How exactly do you go about designing the structure? Is there some sort of code or guideline to design chimneys?

 

[JAE]

CMU block or Brick?

I would use the provisions of ACI 530 (the MSJC code).

 

[JoeBaseplate]

JAE, its supposed to be brick.

 

[SlideRuleEra]

JoeBaseplate - Technical Notes 19 thru 19E (a total of six documents) on the Brick Industry Association website may help. Tech Note 19B is specifically about residential chimney design (assuming this project is for a residence). Here is the link:

http://www.gobrick.com/TechnicalNotes/tabid/7658/Default.aspx

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[JoeBaseplate]

SlideRule, thanks.

Isn't chimney design kind of a specialty thing that very few engineers know about?

 

[ztengguy]

25 feet above the roof line might be an issue, even if one story home, the end chimney would be over 40' tall correct, and don't they have to cantilever structure so you dont have anything in contact with them?

 

[a2mfk]

What plan dimensions can the chimney be? What area of the country are you in wind/seismic? Even small chimneys in Florida can be a pain in the butt if we are talking residential because of wind and because they are usually wood-framed. You may have to look into a steel moment frame or CMU or some type of structure and then treat the brick as a cladding...