Laminated beam

[tuolumne]

If cost is a factor, think about a steel-wood hybrid beam.

An inexpensive 1/4" thick steel strap along the bottom of a wooden beam would make it very strong. Also, a pair of 30' 2x6's with 1/8" steel sandwiched in between would be super strong and rigid. Slow cure epoxy is great for laminating wood to steel, and Gorilla Glue isn't bad either.

There's nothing wrong with composite beams as you describe; I just wounldn't stand under your 2x6 version going 30 feet! Flitch plate beams (vertical steel sandwiched between wood) are a waste of money and good bolts. The steel in the center is just wasted, and there's not enough at the top and bottom to do much good. In construction, LVLs seem to have made them history. Making a composite beam with steel plates top and bottom is good sense and very effective if done correctly. This is just an I-beam that uses a wooden web in lieu of steel. Good bolting or glue is required for shear transfer.

For the gentleman that suggested a double 14" LVL. I believe your progam includes bracing at 24" o.c. any more than that and the beam will fail in lateral torsional buckling mode. Even braced at 24" o.c. the deflections are a tad high eh. Rule of thumb for defelctions with wood, never size a beam less than span/2. For example, a 30 foot span should not be tackled with beam less than 15" deep even if strength appears to be OK.

 

[Tom_Veatch]

schmism, do you think this is more than needed judging from your software?.Three 1 3/4x18 x32 ft lvl's .Your calcs show 2 and only 14 deep.I'm thinking too much
...

Bones, check back to post #4 in this thread. The (3) 1.75x18 configuration is very close to the sizing I gave you in that post. The beam is sized by allowable deflection, not maximum strength. Believe me, it's not too much.

 

[bones1]

I got a steel beam price today.$525.00 delivered.Thats a w10x22x30ft beam and I have no idea what beams run.I suppose now I do.

 

[MrJimi]

I got a steel beam price today.$525.00 delivered.Thats a w10x22x30ft beam and I have no idea what beams run.I suppose now I do.

Bones, I need some help here,
your beam is 10 inches wide and 22 inches tall and 30 feet long, is that correct? what does it weigh total or per foot

 

[bones1]

Thats 10'' deep x5.75 widex30 ft long.The weight is 22lbs/ft.Thanks MrJimi.

 

[MrJimi]

Heck, I wasn't even close, will that support your 1,000 pounds in the center ? spanned 30 feet
and it is a H beam or I beam

 

[Tom_Veatch]

Bones, I need some help here,
your beam is 10 inches wide and 22 inches tall and 30 feet long, is that correct? what does it weigh total or per foot

Not quite, MrJimi. Check post #33. The designation W10X22 is for a Wide Flange Beam, 10" deep weighing 22 pounds per foot. Flange width is 5.75 inches.

Bones, I'll second tuolumne in advising that beam should be adequate, although I notice that your working load has changed from 1000# in post #1 to 2000# in Post #23. If the 2000# is the correct figure, I'll encourage you to consider the W12X26 (12" deep, 6 1/2" flange, 26#/foot), for the extra margin and stiffness both transverse and lateral. The W12 beam should have roughly the same deflection under 2000# as the W10 under 1000# loading. I also strongly encourage you to pay attention to tuolumne's recommendation for lateral bracing or blocking.

When the beam is loaded, the lower flange is in tension, the upper in compression. Think of that upper flange as being a long thin column in compression - not exactly the same situation, but similiar. A long thin member in compression is just looking for an excuse to buckle. I know, intuition says the vertical load on the lower flange will keep it from rolling sideways, but it won't. Stabilize it with lateral bracing or, sure as the world, it will twist and buckle under load.

To get an intuitive feeling for what happens, think of picking up a long 1x12 and trying to hold it with the 12" dimension vertical. That sucker will twist and bow at the least provocation. To quote tuolumne from post #43, "Think 300 lb wet noodle". The steel is much stiffer and doesn't exhibit the behaviour quite so drastically, but the principle is much the same.

Good luck!

 

[tuolumne]

I got a steel beam price today.$525.00 delivered.Thats a w10x22x30ft beam and I have no idea what beams run.I suppose now I do.

That sounds pretty expensive, but it's still better than the LVLs...and believe me, it will actually be easier to install. The price may be that high because it's a special order for that supplier. You may actually get a better deal on a heavier beam if it's something they have in stock. A W14x22 is much more common, the same weight and a bit stiffer. It has a narrower flange, so lateral bracing is even more important. Just look for something a minium depth of 10" and minimum weight of 22 lbs per foot and take what's available. You have plenty of room so a W16x26 which is very widely available would also work well. Good luck.

 

[tuolumne]

Tom - a good simple explanation of the lateral buckling phenomenon. It is counterintuitive for most folks. That top flange can't buckle downward because of the web, so eventually she just peels off to the side.

Bones - If you don't want to bother with the lateral bracing, use a W12x26. Keep in mind that this beam is not overdesigned in any way. When the beam weight is subtracted, you can hang 1,963 lbs including the chainfall before you get lateral-torsional buckling. Put a brace at center span, and your allowable load goes to over 7000 lbs. Keep in mind that these numbers are for 50 ksi steel which is the commonly material for wide flanges today.

 

[schmism]

schmism, do you think this is more than needed judging from your software?.Three 1 3/4x18 x32 ft lvl's .Your calcs show 2 and only 14 deep.I'm thinking too much

My softwere assumes some basic braceing cryteria that may not be applicable to your situattion.

To address that issue you need more material in the beam to make it stiffer.

Therefore (is it more than needed?) no the quote you got seems reasonable for the condition you have.