Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


What do you design for overstrength - light frame

What do you design for overstrength - light frame

What do you design for overstrength - light frame

First situation:
Imagine a 3rd story wood shear wall: the east end supported by an east-west beam and the west end supported by the east endpost of the wall below.

Technically, this is vertical irregularity 4, and columns and beams supporting this wall should be designed including overstrength per ASCE 7-10 I think it is obvious that the beam should be designed for amplified seismic load, and whatever column supports the east end of the beam. But what about the east end post of the second story shear wall, which is below the west end post of the 3rd story shear wall?

1) Perhaps, since this end post is part of a shear wall, is need not be designed for any overstrength.
2) Perhaps, since this post supports the discontinuous beam, it should be designed for 3rd story overstrength loads, but 2nd story loads need not be increased
3) Perhaps all earthquake loads, even 2nd story loads, should be amplified, since I found nothing in the code explicitly considering 3rd story and 2nd story loads separate.

Second situation
Now imagine a 3rd story shear wall with a large opening below it, but both end posts are continuous to the foundation. The west end post is supported by the east end post of a 2nd story shear wall. The east end post is supported only by a continuous post; there is no shear wall below this end. Should either 2nd story post be designed for omega?

1) Perhaps both are considered continuous parts of the shear wall and neither is designed for overstrength. This seems to contradict ASCE 7-10, but it might be interpreted that in wood framing these columns are not discontinuous and only need be designed for redundancy.
2) Perhaps the east column is designed for amplified seismic load, as it is a "column... supporting [a] discontinuous wall... having... vertical irregularity type 4", but the west post, being part of a wall, need not be designed for overstrength.
3) Perhaps the west post is also considered a column supporting a discontinuous wall, rather than just part of another wall, and should also be deigned for overstrength.

RE: What do you design for overstrength - light frame

not to but rude, but.

as i tell architects, builders, clients... send me a sketch

RE: What do you design for overstrength - light frame


Lets see if this works.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


eBook - Mastering Tolerances for Machined Parts
When making CNC machined parts, mastering tolerances can be challenging. Are general tolerances good enough? When does it make sense to call out for tighter tolerances? Do you need a better understanding of fits, datums, or GD&T? Learn about these topics and more in Xometry's new e-book. Download Now
eBook – How to Choose the Correct Corrosion Testing Method
When designing a metal component, engineers have to consider how susceptible certain alloys are to corrosion in the final product’s operating environment. In a recent study by NACE (National Association of Corrosion Engineers), it was estimated that the direct and indirect costs of corrosion in the United States is approximately 6.2% of the GDP. In 2016, that cost exceeded $1 trillion dollars for the first time. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close