Posts by retug (37)

ASCE 41 - What Gives?!?

Lately I have found myself doing a lot of seismic retrofits of existing structures.

These buildings are often analyzed utilizing ASCE 41 and I have a few complaints with the standard that I have not found answers too... hopefully someone reading this site can help me out with these.

• Soil bearing pressures

  • In traditional ASCE 7 seismic design, you get to divide your equivalent lateral forces (ELF) or MRSA forces by an "R" factor... In ASCE 41, there is no "R" factor. There is an "m" factor that is ~"R" from my understanding, but these two terms should not be mixed and matched.
  • Given that your seismic loads from ASCE 41, e.g. BSE-1E or BSE-2E, are not divided by "R", the loads are MASSIVE! If I were to report these loads to my geotech engineer, they would laugh at me
  • I thought that maybe ASCE 41 would allow me to divide by the "m" factor, but instead, you get a measly factor of 3 when design your foundations
  • 
  • Coming from a high seismic area where I typically have an "R" of 8 and get to reduce my soil pressures by ~%10 with ASCE 7, only getting to divide by 3 is a real pain on my foundations. Contractors do not like these massive foundations.

• Drift Limits

  • From the reading I have done, there are no drift limits in ASCE 41! What's up with that? It makes my life easier as a designer, but I have to feel like it should be considered.
  • Lots of moment frame designs according to ASCE 7 are drift controlled...

• M Factors

  • M factors and R factors between ASCE 41 and ASCE 7 often do not match at collapse prevention. For example, BRB "m" factor is 7.5, while a BRB "R" factor is "8", what's the difference?

• Force displacement curves

  • As innocent looking as this graph is, it is often extremely confusing to decipher
  • I will dig into this graph in the future
    

All images are taken from ASCE 41, I do not own these images and all rights belong to ASCE 41.

Website Creation - Part 1

While this website will mostly focus on items in the architecture, engineering, and construction (AEC) field, I figured I could start with posting about how I made this website.

This website was created with the Django framework (a term I just learned throughout this process). It seems to be popular among those in the python community and I learned about it from being a part of the local python club here in Utah. 

I started on this project on July 1st of 2021, the day my wife started up her night float rotation in the hospital. She works crazy hours during this rotation and I figured now would be the best time to start to learn web development.  I had (2) months to do the heavy lifting before the wife returned home. The heavy lifting of the project was completed today, August 23rd; a 54 day project. I would estimate that I spent ~ 2 hours a night working on this website bringing my total time to build this website to around 100 hours. 

In retrospect, I wish I would have gone with a preconfigured blog website like wordpress or wix; but I learned a ton thorough this process. Terms like "sudo," "nano," and "linux" "databases" all mean something to me now. I know the basics of how to configure a linux machine; how to setup website domains etc.

The process has been fun. Stay tuned! (I clearly need to add a spell check to my text editor as well; it is kind of ugly how many misspelled words I see)