I Beam help needed

[EddieWalker]

Part of my lake design will have a cement spillway to handle the runoff during heavy rains. This could involve a million gallons of water, so it needs to be a substantial spillway that will not erode.

It will be built at the edge of my dam on virgin soil with a shallow drainage to the creek.

To handle large quantities of water, I need to make it 18 inches deep and 16 feet wide. I'm gonna add a few feet to this and build it 20 feet wide.

The sides will also be concrete, which will create an area that will be very dificult to get through when walking along the dam. It will also be impossible to drive over unless I build a bridge across it.

I want to put two I-beams across the span. My thinking is that I'll rest the ends of the beam on a concrete footing. In the center I'll fasten the I-beam to a concrete footing with some large bolts.

This should allow for expansion of the I-beams with the changes of tempatures. They will be spaced at the width of my tractor tires and decked with PT 2x6's.

My question is what sized I-beams can I use to span ten feet and support a 4,000 pound tractor? Lets say 6,000 pounds max weight for both beams combined?

Or if anybody knows the link to a page with the ratings for various sized I-beams. I can buy any size, but would prefer to not waste money buying something rediculous.

I've also read through all the previous posts on bridges without seeing anything that would work. I'm not going to do the trailer method or any other scrap material. Only new I-beams will be used.

Thanks,
Eddie

 

[Parttimer]

If you break up the span by using a tooth design spillway, you could minimize the span-spans. You are in affect designing a bridge with abutments located on a spillway. There are alot of considerations given within the design of this structure, I am sure you are aware. I do not have my pe stamp in your home state, so I can not size a beam for you. Try contacting you local steel company that would supply the beams. They usually have "in-house" engineers on staff for shop drawings and proofs on larger jobs. They may size them for you just because you are going to purchase through them. That project sounds so cool, wish I was building it. good luck.

dave

 

[scott_vt]

Hi Eddie,
Ive got one of the mechanical engineers working on your problem /forums/images/graemlins/grin.gif Hopefully will have an answer by the end of the day. I told him you were spanning 20 ft with a support in the middle.

scotty
ps Try this link also I Beams

 

[EddieWalker]

Dave,

I think you hit on the problem I'm encountering. Nobody wants to say this size will work and than worry about liability down the road. My steel supplier just supplies the material, no design or suggestions. They did say to find a bridge and measure what sized steel it has. I don't want to build something to handle highway traffic, just get my little tractor over it.

I have no issues with usung PT 2x12's, but would really prefer steel to get it done once and never worry about it again.

If I could find a chart someplace that said such and such an I-beam supports a certain amount of weight over a known distance, than I'd be able to make an intellegent desision.

Otherwise, I'm likely to spend three or four times the money buying something way too big and wasting money.

Scotty.

Thanks for the help. If your more comfortable, you can email it to me. Like I just said, all I need is some standard loads for an I-Beam.

Or a website with some examples of what others have already done. Some body has to have built one with some knowleged of what works.

Eddie

 

[Parttimer]

Scott, I just added that web site to my favorites, lots of convenient info, don't even have to run and get my tables for section mods just a click away. Thanks.

Dave

 

[Parttimer]

http://www.richmond.ky.us/Departments/Codes/References/Refs/Chart%20for%20steel%20beams.pdf

go to this site. You may be able to size it yourself. charts on steel beams and spans and loads.

ps a Kip = 1,000 pounds


once again good luck.


dave

 

[npaden]

I would think it would be cheaper and easier to just make the spillway shaped like this:
\ ------------------------------------------------ /
-- \ ------------------------------------------- /
---- \ --------------------------------------- /
------ \ ----------------------------------- /
-------- \ ------------------------------- /
----------- \______________________/

(without the dashed lines - I had to put them in there for spacing)

Except not as steep of angles so you can just drive the tractor down and across the concrete spillway.

Only drawback to that design is that if the water is running hard you aren't going to get across it.

 

[EddieWalker]

Dave,

I'm pretty confused on the charts and hope you can explain to me what it says.

For example, at the top of the chart it says W8 in. Is that the same as a 8 inch tall I-beam?

Ok, if that's right, the next question is what do the colums under it mean?

I'm looking at the 10 ft clear span and in the column of 10lbs kips it says 17.

Does this mean that an 8 inch I-beam with a weight of 17 pounds per foot can handle 10,000 pounds over a ten foot span?

Thank you,
Eddie

 

[EddieWalker]

Nathan,

Your idea was what I was going to do originally, but because of my fear of being sued, and liablity issues, I've decided to build the bridge.

The lake is going to be part of my RV Park that I'm slowly developing. Guests will be walking around the lake, fishing and even bike riding. After a heavy rain, the water level will rise considerably and drain for several days. If I don't provide a safe way for them to cross over the water, and they get hurt trying to wade through the overflow, even if it's only an inch deep, I'm in trouble.

My next idea was to build a simple foot bridge across and drive the tractor across at a lower point, or not ever crossing the area with it.

This didn't make allot of sense to me. If I'm building a small bridge, it might as well be big enough for the tractor and lawn mowers.

Now I'm at the point that the simplest, easiest and strongest method is to put in two I-beams on concrete footings and PT wood for decking.

It's not a done deal yet, so if anybody else has some ideas, I'd love to hear them.

Thanks,
Eddie

 

[dooleysm]

"so if anybody else has some ideas, I'd love to hear them."

Ok, turn the spillway into a water slide and get really big tires for your tractor so you can drive THROUGH the lake. Your foot traffic and tractor crossing issues are both solved.

I asked an ME buddy of mine and he told me he needed $100/hour consulting fee to look up all the calculations he has forgotten.

I emailed a Civil Engineer buddy, but I'm not sure he knows how to work a computer.

So you're stuck with the advice of a Computer Scientist, which is the first set of ideas.