I Beam help needed

chili · Apr 6, 2006

Eddie, my chart shows a W8x24 (grade A572-50 or A992) spaning 10'-0 carry a uniform load of 46kips with a deflection of .43in. With two W8x24 supporting the load should be plenty. Are the beams going to be above high water level? You might also consider bracing the two beams together to keep them from twisting along with good anchor bolts. Of course, this is nonexpert advise but I have stayed at a holiday inn before. /forums/images/graemlins/grin.gif

EddieWalker · Apr 7, 2006

Thank you everyone for your help and advice.

I should clarify this just a little. The spillway will be at the point just after where my dam ends. It will also be real close to the property line wtih the runoff staying inside my side of the trees, but not much room on the other side for anything else.

This will be used for foot traffic and lawn mowers, including my little tractor.

The bottom of the I-Beams will be right at the same height as the dam itself. If water is going over the dam, than I got bigger worries than the bridge. /forums/images/graemlins/shocked.gif /forums/images/graemlins/grin.gif

There wont be any major floating material unless the occasional branch gets in there. The area just before the overflow will be very shallow. Max depth will be 2 feet for at lest 50 feet out. There will also be allot of water lilies growing there once they get established.

I did consider using culverts, but since they are such a common source of leakage in most ponds, and what it takes to make them waterproof, I figures pouring footings and a bridge would be just as dificult, but work better.

My thinking is that ninety percent of the time there will be no more than an inch or two of water going across it. What I'm worried about is those times when we get 5 inches of rain all at ounce!! /forums/images/graemlins/frown.gif /forums/images/graemlins/shocked.gif /forums/images/graemlins/mad.gif

Seems to me that two W8x24 beams set at the width of my tractor tires would be plenty strong enough. I will anchor it in the middle and float the ends for expansion. And after reading your replies, I'll also tie the beams together at four points. Two on each side at the thirds.

Any thoughts on what would be the best material for this?

My fist thought is 2 inch galvanized pipe. I could weld on some plating to the ends and bolt it to the I-Beam.

Again, thank you
Eddie

rambler · Apr 7, 2006

My fist thought is 2 inch galvanized pipe. I could weld on some plating to the ends and bolt it to the I-Beam.

-------

Dad made 2 bridges over the ditch on our property. He ran a rod through the middle of the Ibeams, with pipes like you say as a spacer between each Ibeam, threaded over the rod.

These bridges are a little bigger scope. 12' span, take the combine & tractors over it all the time. It is 16' wide, something like 10 I beams under equally spaced, 4x6 white oak planks across. Concrete walls on each side.

Dad likes to overdesign things, fortunately. Made it when he had a 3000# tractor pulling a 2 row combine. Now I take the big gravity boxes, big self-propelled combine, etc. over them. Found out they are real well built when the fertilizer guy drove over one with his truck........

--->Paul

radair · Apr 7, 2006

Pedestrian bridges are generally designed for 85 psf (yes, that's a big load)! The bridge width will obviously affect the magnitude of both live and dead loads.

The other consideration is what you'll be using for decking. You may want to use 3 or more stringers, not to support the tractor, but to allow you to use 2x or other readily available decking. Also, I assume you'll need railings, so consideration should be given as to their attachment.

Diagonal bracing is always a good idea to keep everything stiff and where it belongs.

I sent you a PM with more info.

chili · Apr 7, 2006

Eddie, You might think about welding some 3/8" stiffner plates on each end, at the center support, and midway between your 10'-0 span. This will stiffen up the beam and give you a place you could weld a horizontal brace to. Your not going to get much diagonal on a W8x24. A L3x3x3/8 angle as a horiz. brace should suffice. Just my opinion. I believe there is a teflon pad with a backer plate that you might consider placing between you beam and bearing plate to allow for movement. They use these alot on expansion joints in buildings at steel connections.

Defective · Apr 7, 2006

( My fist thought is 2 inch galvanized pipe. I could weld on some plating to the ends and bolt it to the I-Beam.)

Eddie,

I wouldn't suggest using pipe here. It'll eventually rust from the inside out despite the galvanizing.

I'd use either angle or channel. Either way, try to position it so water & debris cannot pool inside it.

EddieWalker · Apr 8, 2006

( I'd use either angle or channel. Either way, try to position it so water & debris cannot pool inside it.
)

OK, I like this idea. Angle iron in an upside down V.

Would you weld it into position, or weld a plate on the end and bolt it in? I think the bolts would be better because I can fabricte them in the shop and install them easily in the field.

Eddie

EddieWalker · Apr 8, 2006

Radair,

You keep giving me more to think about!! /forums/images/graemlins/grin.gif

The third stinger is a good idea. I hadn't even gotten there in my planning yet. To get my tractor and six foot mower across, it will have to be 8 feet wide. I can put the stingers three feet apart with one foot of overhang.

I'm also thinking that I can build a railing with the posts coming out of, or attached to the concrete footings. Make it totally seperate from the decking.

Railings..... more to think about. /forums/images/graemlins/confused.gif

Eddie

CurlyDave · Apr 8, 2006

I did consider using culverts, but since they are such a common source of leakage in most ponds, and what it takes to make them waterproof, I figures pouring footings and a bridge would be just as dificult, but work better.

Eddie:

I don't think I was communicating my idea correctly.

I wasn't suggesting using actual culverts, I was suggesting making passageways similar to culverts. They would be cast into the spillway as you pour that concrete -- no leaks. I am attaching a drawing.

I have shown four passages for water, although you could make any number you wanted.

EddieWalker · Apr 8, 2006

Dave,

Thanks, your right. I mis-understood you.

Your method would sure be allot stronger and I realy like the arches. I cold do something like TxDon has on his land. An arched bridge with rock on the sides!!

That sure would look nice!! /forums/images/graemlins/laugh.gif

Now I'm wondering if I could do two very large arches spanning ten feet each. A double arch, but a triple would work to.

How to make an arch????

Can a large metal culvert be cut and opened up??

The cutting is easy enough, but how to spread it???

Is there a product out there to form an arch???

My other thought is to buy a super large culvert, or several smaller ones and burry them half way and use the top half as the arch. It would take four six foot culverts to get simlar flow as the I-beam bridge. Or that's what I'm thinking.

Not the best solution either. /forums/images/graemlins/frown.gif

Thanks
Eddie