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

Wind Load directions and amplification factors.

Wind Load directions and amplification factors.

Wind Load directions and amplification factors.

In ASCE 7-10,2.3.2 are given the basic combinations for strength design:
1. 1.4D
2. 1.2D + 1.6L + 0.5(Lr or S or R)
3. 1.2D + 1.6(Lr or S or R) + (L or 0.5W)
4. 1.2D + 1.0W + L + 0.5(Lr or S or R)
5. 1.2D + 1.0E + L + 0.2S
6. 0.9D + 1.0W
7. 0.9D + 1.0E

In equation 4 and 6 , W refers to wind,and in 5 and 7, E refer to the earthquack load.
My questions are:
1-is there any redundancy/overstrength factor to multiply wind loads(obtained by manual calculation or by software) with to obtain W? I mean to obtain the seismic load Eh we had to multiply QE(load obtained by seismic analysis) by a redundancy/overstrength factor.Is this a similar case? or W=wind loads obtained by applying wind pressure.
2-what are the directions of the wind that we should consider in the load combinations?I mean 2 orthogonal directions are sufficient?
3-For seismic loads ASCE 7-10,12.5 for each seismic design category gives a method of combining load effect obtained from applying seismic load in each direction.Is there a similar thing for wind? or the wind cases obtained for each direction are sufficient?
Thank u.

RE: Wind Load directions and amplification factors.

1. Redundancy and Overstrength do not apply to wind loads. My (poor) understanding is that this is because structures are designed to resist wind entirely within the elastic range, while seismic design allows for some use of plasticity and ductility.

2. Depending on your structure, directions other than your two orthogonal grid directions may govern. Check out the Citicorp building case study for an example.

3. I'll leave a definitive answer here for others. I know AASHTO has provisions for wind at different skew angles and combined in multiple directions.

The name is a long story -- just call me Lo.

RE: Wind Load directions and amplification factors.

1. No, these do not apply to ASCE 7 wind loads.
2. See Figure 27.4-8 for considering wind directions. You are also free to add more.
3. See 2. There is no requirement for wind loads corresponding to seismic orthogonality combinations.

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! Already a Member? Login


Research Report - How Engineers are Using Remote Access
Remote access enables engineers to work from anywhere provided they have an internet connection. We surveyed our audience of engineers, designers and product managers to learn how they use remote access within their organizations. We wanted to know which industries have adopted remote access, which software they are using, and what features matter most. Download Now
eBook - Managing the Context of Product Complexity Using the Digital Twin
Keeping track of changes to complex products is difficult—think Aerospace & Defense equipment, new generations of commercial aircraft, and software-based automobiles. A new way to managing the digital context of the physical product is required and the answer is the Digital Twin. This ebook explores the opportunity available for Operations and Maintenance for the Digital Twin. Download Now
White Paper - Trends in Industrial Filtration
Substantial progress has been made in filtration technologies in recent years. New filter media materials, designs and processes have led to filters that are more efficient, reliable, compact and longer lasting. This white paper will discuss the various trends that are impacting operational responsibilities of MROs today and the resources that are available for staying up-to-date on the latest filtration solutions. 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