Weight capacity of my concrete/steel bridge?

[2manyrocks]

I need a forestry mulcher to come in and do some clearing. The operator said his Cat 299d with the mulching head weighs 15,000 lbs. The last guy to bring a compact track loader said his weighed 10,000 lbs and was able to cross without any issues, but 15,000 lbs is a lot of weight.

The bridge is 10" thick of concrete with a 13 foot width x 12' length. It is sitting on three I beams. The upper flange is inside the concrete, but the exposed portion is 8 1/2" deep with a 4 1/4" flange that seems to measure 5/16" thick.

The concrete pad does not have any cracks. The beams need repainting, but are solid. I remember that mesh was placed in the concrete when it was poured, but I do not recall how much or if there is any rebar in the pad.

Any ideas as to whether 15,000 lbs is too much for my bridge?

 

[ruffdog]

I don't know how your bridge was constructed and with what materials, but, It looks pretty sturdy and a short span.

 

[2manyrocks]

If I could get a reliable estimate of what the weight capacity is, that would help me sleep better. I don't want to damage it and have something else expensive to redo.

 

[MattB4]

Can't give a reliable estimate but you might consider a few 6x6 wooden posts in the center from bottom to beam to decrease total span loading.

 

[YanmarFever]

A friend of ours husband had a bridge like that, he came home for lunch in a loaded dump truck and thought nothing of crossing his bridge to get to his house.
He obviously did not know how much weight was in the back of the truck.
The bridge collapsed, his truck went in the water, and he had a heart attack and did not make it.

Please be careful, maybe have a retired engineer look at it, I'm sure there are some in your town.

 

[Snobdds]

I could calculate it if there were axles, but since It's a track loader...that is almost impossible to calculate.

Like someone else said...support the bridge at the center with cribbing.

It looks fine to me.

 

[Topzide]

To be safe, I'm with others about cribbing under it for the equipment to cross. That would be the safest thing to do short of hiring an engineer to figure the load handling of your bridge.

 

[LittleBittyBigJohn]

I'll preface this by saying I'm not an engineer. The closest I beam I found to your dims will hold about 7K lbs midspan load each. I would say 2 beams with no concrete would probably hold it. If it were me I'd roll on.... Probably...

 

[4570Man]

A tracked skid steer is distributed across its footprint pretty good. I’d drive across that bridge with no hesitation. Even if you had an actual engineer look at it I’m not sure how much they would help you without knowing how the slab was constructed or the construction details of the foundation.

 

[Chewwy]

The load capacity of the concrete between the I beams is likely the weak point. If the tracks of the Cat are substantially over the I beams you are likely ok. If they are not, the concrete itself might not support the weight. If you go the cribbing route, be sure to support the concrete between the beams.

If you really want to sleep well, hire a civil/structural engineer.