Weight capacity of my concrete/steel bridge?

[ning]

At a minimum I'd consider renting some of those 1" steel plates, drop them on top, so that the load is spread across the concrete.

 

[paulsharvey]

Here, I think, you would probably need a building permit, a DEP permit, and possibly something from water management or army Corp.

 

[yooperdave]

The main concern I would have is the condition of the concrete and steel. If the concrete and steel are in good shape, I would not be concerned with 15,000#. The bridge is short and stout. Do not park the truck on the bridge and see what a few days of intended support will do. If the concrete and steel are degraded, then you will not get the intended load sharing and capacity.

 

[SenileTexasAggie]

Have you considered using a skidder bridge? Here is a video of a skidder bridge in use. At the 9:00 mark the video shows how it was constructed:

.

Senile Texas Aggie

 

[deezler]

A track loader? How long are it's tracks?

You said the bridge was 12' long. Is that the span underneath, or the top deck length? The free span is what we need to focus on. I bet the tracks on the machine are as long as you bridge. In which case less than half the weight of the machine will be supported near the middle of the bridge. I would get some 2x12s to toss down as runners to help spread the load, avoid any high pressure points under the tracks, and take the abuse instead of your concrete.

Should be fine. Width not an issue? Like someone else said, take note of the I-beam vs track width consideration. Best if it matches up.

Edit: i could just read more better, lol. 299d has 7.5' long tracks. hmmmmm.....

 

[Jims1025R]

Thread drift, but having spent 28 years as a volunteer firefighter, we drove trucks to the calls, they're heavy! If you are uncertain that your private bridge would support a firetruck, it's worth preplanning that with the local fire department. Bad is a fire truck responding to your call breaks your bridge. Worse is that the first truck breaks your bridge, and is stuck there, then your fire is not going to be put out either, and everyone is unhappy.....

 

[Chewwy]

A track loader? How long are it's tracks?

You said the bridge was 12' long. Is that the span underneath, or the top deck length? The free span is what we need to focus on. I bet the tracks on the machine are as long as you bridge.
. . .

You lose the bet.

The length of the tracks on Cat 299D in contact with the ground is less than 6 ft.

 

[Streetcar]

Find steel table with capacity of the beams , ignore deck for load capacity.

 

[yooperdave]

Find steel table with capacity of the beams , ignore deck for load capacity.

I would limit the yield strength of the steel to 15 ksi. This will at least address some degree of degradation and lower material strength due to age. Steel has come a long way during the past few decades.

 

[zzvyb6]

My power company brings thick coiled wire mats to cross my concrete driveway with their 26K lb utility trucks to improve load distribution. Another suggestion would be to measure the deflections along the spans when a group of light to heavier vehicles cross it. It will naturally flex because of the bending moments, but 'how much' is what you care about. Given 4 or 5 loads and a dial indicator, a simple strain graph may help you determine what a safe crossing load is. Your County highway department ought to have a bridge deflection chart on file showing what deflection measurements are considered 'safe' for a given roadway span.

Also, the center of the bridge may not be the problem, but the embankment piers. If they sink, then this becomes another 'unforeseen circumstances' issue. Remember, he's got to come back across your creek when done ! (It isn't Shitz Creek is it ?)

If the contractor has access to the right kind of trailer, park the empty trailer across the bridge, supported at the embankments. Then drive it across the trailer as it acts like it's own bridge. Don't add supports at the center for it. Let it deflect.