1970's unreinforced masonry 1

[slickdeals]

Folks,
I am looking at a set of drawings for a building built in 1970 in South Florida.

The Building code of the time (South Fl. Building Code) required masonry compressive stress to be calculated based on gross area of masonry and the stress not to exceed 150 psi for a type M mortar for concrete blocks.

Shear stress are limited to 0.1 * compressive stress (15 psi).

Was the shear stress to be calculated based on gross area of masonry or net area? Can anyone point me in the right direction?

 

[a2mfk]

Ron- very interesting, do you have any links to reports or anything published that you would recommend? Other than me just hitting up Google... I was in high school at the time and not in the field, though we had friends from Central FL go down to help clean up. Probably not thinking too much about structures whatsoever to be honest at that time in my life...

 

[ron9876]

a2mfk is that a cheap reference to my age? LOL There were plenty of articles at the time in both the local papers and technical journals. Don't have a specific reference. It took the experts a while to decide on the actual wind speed. But in my career down here the rest of the storms have been minor and they still caused damage. All kinds of personal stories.

Two houses with a wood fence between still standing (likely due to wind direction) with a UPS truck upside down between one of the houses and the fence.

One thing that storm taught me as a young engineer is that a structure will work even if a little underdesigned but you must get the connections right. Can't redistribute forces if the connection fails

 

[a2mfk]

Ron- I can see how it would come off like that, my bad. Rephrase, "May I call on your seasoned wisdom and first hand experience with Hurricane Andrew? I was not so far along in my career at the time..."

FWIW I just realized this was the 13th year of my career. When I go back to FSU for games I am very aware of how long its been since I was in college regardless of how "..it felt like yesterday I was up here..." Age sneaks up on you!

I have thoroughly enjoyed my experience and learned a lot about how structures react to real world wind (and water) forces from doing forensic engineering and just being around for the 2004 hurricanes and Katrina. And I completely agree with you, when it comes to wind it will find the weaknesses, especially in residential construction- garage doors, windows, and connections (particularly roof truss)...