×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*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.

Fundamental frequency of a single-pole sign structure

Fundamental frequency of a single-pole sign structure

(OP)
In order to determine wind loads using ASCE 7, there seems to be adequate information available regarding fundamental frequency and damping ratios for flexible buildings.

However, in researching, I have not been able to find a good reference for calculating these factors, nor a table or chart referencing suggested values for single-pole sign structures.

Can anyone point me in the right direction?

RE: Fundamental frequency of a single-pole sign structure

ASCE 7-98, Equation 6-20; F=qz*G*Cf*Af

The values of qz  (velocity pressure evaluated at height z of the centroid area of Af) are the same as MWFRS except the value of G = 0.85. The design forces can be determined using appropriate Cf (net force coefficients from tables 6-9 through 6-12) and Af  (area normal to wind) for each component.

Guide To The Use of The Wind Load Provisions of ASCE 7-98 (also available for 7-02) published by ASCE is an excellent reference for wind load calculations.

RE: Fundamental frequency of a single-pole sign structure

(OP)
Thanks ERV.

However, for designing the main sign structure (pole and foundation), it is not considered components and cladding, and "G" must be determined based upon a flexible or rigid structure (per Section 6.5.8).

Thus, my original question re: where can I find a good source for fundamental frequency and damping ratio, for single pole sign structures.

RE: Fundamental frequency of a single-pole sign structure

Correct. If the structure has a fundamental frequency less than 1 Hz. it is considered a flexible structure, and the gust factor G = Gf, will be calculated per 6.5.8.2 Flexible or Dynamaically Sensitive Structures (ASCE 7-98). Gf = 0.925 (Equation 6-6).

www.geocities.com/lpittack/cae614proj.html

RE: Fundamental frequency of a single-pole sign structure

(OP)
Thank you ERV.
You have been most helpful. And thanks for the quick response.

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.

Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a partâ€™s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. 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:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!