Apr 3, 2020

Ask The Experts: Social Distancing Tip #43

Hey, every engineer slaps on a big factor of safety to cover his rear, right?  It's not uncommon to hear an "armchair" engineer confidently ask, "So... how much factor of safety did you add?" as if it's the world's most obvious fact that all engineers throw in a bunch of fat and over-design the heck out of everything. 

I actually don't know any structural engineer that does that, though there's probably a Schmoe or two out there.  Safety factors that have been refined over decades of practice and experience are already built into the Building Code, so there's no need for a good engineer to slap on an additional "factor of ignorance".

I have my theory about the origins of this misconception.  Most people have at least a "feel" for the weight of things, but they have little concept of the magnitude of design wind or earthquake forces.  That's partly because lateral loads are more complicated and harder to visualize, and partly because design wind and earthquake loads occur so infrequently they may never happen in a person's lifetime.

Now, when it comes to the minimum separation for proper social distancing, that's a different story. 

[Credit for this one goes to David Winn.  His email to me said, "I was on the phone with a client yesterday and he commented that we should put out a list of social distancing tips from engineers since we are so good at it."  He then gave me a list of brilliant cartoon ideas that I've attempted to recreate here.]