Happy Thursday! This is Back of the Envelope – the place to learn structural engineering in tiny bites 🍪.

Today I am going to share a “cheat sheet” I created to help myself with ASCE 7 structural irregularities (actually, they are more like small notes added to the margin – you’ll see).

Let’s dive in.

(Estimated read time = 1 minute and 20 seconds)

The Challenge

A little bit ago, some questions came up while a colleague was developing the fee proposal for a project:

Good questions.

Simple: Just look at “Table 12.3-1 Horizontal structural Irregularities” and “Table 12.3-2 Vertical Structural Irregularities.”

…Right?

Well, yes, but not really.

Here’s what the tables look like: (for illustration purposes only – don’t actually read it right now)

For me, it wasn’t easy to tell, at a glance, which requires dynamic analysis and which requires 3d modeling…etc.

The Solution

If you look closely (figuratively speaking), here are the pertinent sections:

1/ “Table 12.6-1”: This is where ASCE 7 talks about when ‘equivalent lateral force procedure’ is permitted and not permitted (therefore requires dynamic).

2/ “Section 12.7.3”: This section discusses when a 3D model is required.

So I thought – hey, what if I highlight them on the table with different colors and add a quick note to remind me what they are.

Here is the result:

That should help me avoid flipping back and forth between the pages.

I would also be able to quickly tell the implications of each irregularity by glancing at the table.

If you think this is helpful, I recommend you do the same: read through each section; create your own notes and highlights to add flairs to the table.

(Or you can download mine here – sharing is caring 😊)

And this is all for now; time for a quick engineering joke:

The end. Hope you like it – have a good day!

Andy Lin
Back of the Envelope/Structural Engineer HQ