×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

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!

*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

Force on anchor bolt connection
2

Force on anchor bolt connection

Force on anchor bolt connection

(OP)
Hypothetical scenario-A column is being erected with a grouted anchor bolt connection. During erection the column is free standing and accidentally hit by a large moving truss at the highest point of the column.

I am trying to determine if the grouted anchor bolt connection will suffice. How do you calculate the force that is applied to the anchor bolt connection when the column is hit in such a fashion?

RE: Force on anchor bolt connection

Impact loads appear to be inherently difficult to solve. The key to solving them is to understand that it's really an energy transfer and energy equations must be used. The difficulty comes in a) transferring the energy into force-stress equations via the stress-strain relationship; or b) approximating the force impacting the structure. The approximation method is usually the tried first because it appears to be the "easiest" to solve. The difficulty here is that there is no easy/accurate/comfortable way to convert and energy transfer into a direct force. In design, we use this method but understand that we are significantly overdesigning the structure. If you are doing this for forensic engineering, then the only accurate way that I have found is to use the energy equations. Otherwise, it can be easily shown that your equations contain way too many assumptions/rules-of-thumb to be accurate.

Imagineer


RE: Force on anchor bolt connection

Most steel fabricators and errectors normally provide tempoary bracing to columns and other steelwork during errection such to  maintain the tempoary adequacy of the steel work. My question would therefore be why is it of concern?

As far as physically calculating the impact force the best I could come up with is the Asutralian Standard AS 1170.1 "Dead and Live Loads" which gives and energy type equation for the impact loads of vehicles onto barriers. Perhaps a bit of judgement could be used in applying this equation for your particular application.

From Clause 4.5

F=mV^2/(2d)

where

F = impact force in Newtons
m = gross mass in kilograms
V = velocity at impact in metres per second
d = deceleration length in metres

d is normally taken as the sum of the deflections of both the vehicle and the barrier. For example a car impacting a rigid barrier during parking operations has a d = 0.1 metres and a V=2m/s min.

Perhaps the above equations can be used for your aprticular application.

Regards

Tim
\

RE: Force on anchor bolt connection

Here is one way to determine the effective force. First calcualte the energy of the impact by   .5 x mass x Velocity**2. This would be the velocity and the mass of the object that is impacting the column. This energy would be absorbed by the column based on the equation  .5 x force x d, where d is the deflection of the column. The deflection of the column is (force x l**3)/(3 x E x I). Now, the impact energy would equal .5 x force**2 x l**3/(3 x E x I).
The only unknown would be the force. Once the force is calculated, the anchor bolt can then be evaluated. I hope this helps you.

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


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
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’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:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close