×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Overstressing a bridge

Overstressing a bridge

Overstressing a bridge

(OP)
Just watched this video and was surprised about how much you can overstress some structural elements without causing failure:

https://youtu.be/eHxvj7C0OT8

RE: Overstressing a bridge

Nice video but it may not be overstressed. The bridge uses a shallow stiffening girder as opposed to a stiffening truss; that's why you see pronounced deflections.

Arkansas Highway Department has a website with old bridge plans; I'm going to look to see if this one is in there.

Link

RE: Overstressing a bridge

(OP)
bridgebuster, interesting link. Just wondering what is the oldest bridge in that list...

RE: Overstressing a bridge

Okiryu - I found that link a few years ago and downloaded some plans. A lot of stuff from the 30's; don't recall if I found anything earlier.


Here are the bridge plans:

Link

A Wikipedia link:

Link

RE: Overstressing a bridge

I thought a suspension bridge was supposed to deflect; otherwise, the beams would be carrying the load and not the cables.

We lived up in Colorado years ago and went up to the Royal Gorge bridge. I was talking to an elderly lady about that later, and she said back when they built it, the wind deflections would move the bridge enough that, standing at one end, you couldn't see vehicles at the other end. She said they added additional stiffening cables later. When we were there, watching closely, it looked it was slowly swaying up and down about a foot from the wind. You couldn't really tell it was moving when you were out on it.

When I was a kid, the bridge across the intracoastal canal going out to Quintana beach was a floating bridge- basically a barge. I drove a bobtail dump truck across that one time, and it seemed the end went down about a foot when I drove on. My dad said with the trailer dumps, the operator would come out and motion them to take it right down the middle.

RE: Overstressing a bridge

Of course it deflects. The depth of the stiffening girder/truss affects the amount of deflection.

RE: Overstressing a bridge

Wikipedia article notes bridge was pedestrian and cycles. Also noted bridge was temporarily closed this month because two overloaded buses went over it.

RE: Overstressing a bridge

The weight limit is 10 tons. A story said the bus was 35 tons.

RE: Overstressing a bridge

I think the bus is more likely 35,000 lbs- figuring 8 wheels at 80,000/18 lbs per wheel.

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

White Paper - Design for Additive Manufacturing
With a growing number of parts manufactured directly by additive manufacturing techniques, it is important to lay down design principles suitable for such manufacturing processes and to ensure parts are designed for additive manufacturing. There are several factors that are to be considered at the design stage. Few such design issues in additive manufacturing are discussed in this paper. 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