Building A Bridge

[BTDT]

To me that's a great looking bridge. I hope it serves you well. I got similar negative responses (not from TBN, but from my suppliers) that what I was wanting to do wouldn't work. My bridge (suspension), has served me with no problems for about 5 years now.

 

[Bill Barrett]

As a trucker I have learned if you go real fast over them you'll be fine

LOL +1 and try to do it as smooth as posible!

 

[koop]

To me that's a great looking bridge. I hope it serves you well. I got similar negative responses (not from TBN, but from my suppliers) that what I was wanting to do wouldn't work. My bridge (suspension), has served me with no problems for about 5 years now.

I love suspension bridges! Is it pedestrian use only, or for vehicles as well? I would love to see pictures if you have any.

 

[BTDT]

I love suspension bridges! Is it pedestrian use only, or for vehicles as well? I would love to see pictures if you have any.

Let's see if this link still works.

http://www.tractorbynet.com/forums/photos/90164-bridge-pics.html

 

[RedRocker]

Great bridge koop, I hope you enjoy it.

 

[koop]

Just got the word from the Department of Environmental Quality that no permit will be needed.

My heart goes out to all those affected by the bridge collapse along the Mississippi. This tragic event is particularly sobering for anyone in contact with a steel truss bridge. How does it happen on a state bridge that is frequently inspected?

 

[ktm250rider]

I think that VDOT should have scrapped that bridge before letting a private individual get a hold of it for liability concerns.

Thats the biggest problem today. Who can I blame for my problems. If the bridge fails, its HIS fault. The town shouldnt be liable for it.
Id love a bridge like that. Mines made of a couple of pine logs and left over lumber from building my house. Its not pretty but it works.

 

[Renze]

Renze,

You have seen the picture, I can give you the dimension of every piece of steel you see. Just let me know. I would love to see what your program comes up with.

It would appear I need to reassure everyone that if your program says 40 ton weight limit that I am not going to invite every tandem axle dump truck with 4 pony axles and 23 tons of gravel to come test your results. LOL

Koop,

I am willing to do this in the weekend.
If you really want this, i need dimensions, a kind of grid coordinate from beam joint to beam joint.
Also the dimensions of the beams, is it a standardised profile with a known moment of inertia ?
In Europe we have standardised profiles according to DIN, HE-A, HE-B, HE-M, UNP, IPE where the first character represents the shape of the profile.
I'm not sure if they are the same, but if you have the standard code, someone must be able to find a table of moments of inertia from the internet... Otherwise i have to calculate that as well, and rely on your exact measurements of the profile... ???

 

[Renze]

Koop, when going back and looking at your picture, i see your bridge roughly uses only 3 types of steel profiles. The 4 longitudinal beams in the floor, look like European hot rolled IPE profiles.
The upper beam of the side trusses look like they are composed from sheetmetal by longitudinal welds.
The crossbars look like sets of angle irons, bolted together in the middle by bolts.

It's about an evening of work to calculate the moments of inertia of the non-standardised profiles.
Throwing that stuff into a calculation model isnt that much work at all.

 

[dynasim]

There are a number of people in this thread that think they know more than they actually know.

Rephrased, the question is:

"What is the difference in safety factors between higher speed, higher frequency bridge design versus a low speed, low frequency bridge design."

Condemning someone because they are going to use a well designed, publicly utilized bridge on their own property does not make sense. I am quite sure that there is someone out there that could tell him the facts(The factors are almost certainly in someones structures handbook), without accepting any liability risks(after all, they are objective facts).

I have found that people who say that something complicated can or can't be done based upon "common sense" are almost uniformly mistaken.

The load rating of that sort of bridge is likely well known(they were/are catalog items). Those bridges are very strong(likely stronger than necessary, certainly stronger than a flat bed semi trailer). However, the owner ought to pay a stuctural engineer 4-8 hours to evaluate the bridge, and design the appropriate supports. It will be cheaper than replacing/repairing the concrete after settlement.

<Edit--I should have read the last quote by Renze. Oops>
Chris

P.S. The supports are very important. Make sure that thermal expansion, and soil bearing load are accounted for. If this were my area of expertise, I would help. It isn't, but I know the calculations are relatively simple and quick.