How strong is steel

[Budweiser John]

I've been in the trim carpentry/building game (retired) and lumber span tables were the bible used to select lumber sizes for a particular load or span, such as floor joists.
Now having the retirement time to fabricate some labor saving goodies out of steel for storage or perhaps a boom lift for the FEL
I'm at a loss, other than gut feelings on how much (steel) and in what shapes, channel, sq. tub, angle, or pipe will support, carry or span. Yes, this the domain of the pet agreed engineering community but are there any rules of thumb or tables anywhere that would suggest for example, that a 2X2x1/4 sq. tube 6' long will support more weight evenly distributed than say a 3" channel of the same length.

I'm hoping members get the drift of my question. At this stage in the life time adventure, I'm not interested in a structural engineering degree but as a reasonably good barn yard welder with a head full of project ideas a little grass root TBN guidance is a beautiful thing.

 

[/pine]

How strong is steel

No first hand knowledge here but I imagine there are some types of tables for steel that offer load resistance data for different stock...Good Luck with your query...

Something interesting I heard a long time ago...

...Not sure where this originated or if it's 100% true...but (in reference to your carpentry background) I've heard on several occasions that "pound for pound" (I guess that means dimensioned accordingly and subject to certain types of loads/forces) that #1 (clear/dense)-structural grade SYP is stronger than steel...! ?

 

[JCByrd24]

I'm an engineer and have a good friend who is a builder. He's shown me books designed for builders that whittle down months of class and pages of engineering text into the most useful basics that you are seeking. You must know how to do algebra but the knowledge you are after is out there in concise forms. Most places I've seen span tables usually have a pretty good intro/how to use the tables section that is very helpful. I suggest googling "beam equations".

The property that you most likely are after with regard to comparing two different shapes is moment of inertia (I). This is what makes a 2x8 stronger and stiffer when stood on the short edge like a joist vs on the long edge like a plank. All steel sections have this property published and it's the key input in beam calculations. You will note in the tables in the link below that there is Iy and Ix and one is larger (usually x). This is the same as joist vs plank orientations.

American Wide Flange Beams - W Beam

 

[/pine]

...He's shown me books designed for builders that whittle down months of class and pages of engineering text into the most useful basics that you are seeking. You must know how to do algebra...

I'm guessing but I will go out on a limb say that if you asked a current structural engineering student...They'd say yes they had to learn the theory behind typical design calculations and all the required math-algebra/calculus etc...but these days you just type in all the variables into software programs and it spits out everything you want/need...including supplemental (after install) bracing placement etc...

 

[PapaPerk]

I've been in the trim carpentry/building game (retired) and lumber span tables were the bible used to select lumber sizes for a particular load or span, such as floor joists. Now having the retirement time to fabricate some labor saving goodies out of steel for storage or perhaps a boom lift for the FEL I'm at a loss, other than gut feelings on how much (steel) and in what shapes, channel, sq. tub, angle, or pipe will support, carry or span. Yes, this the domain of the pet agreed engineering community but are there any rules of thumb or tables anywhere that would suggest for example, that a 2X2x1/4 sq. tube 6' long will support more weight evenly distributed than say a 3" channel of the same length. I'm hoping members get the drift of my question. At this stage in the life time adventure, I'm not interested in a structural engineering degree but as a reasonably good barn yard welder with a head full of project ideas a little grass root TBN guidance is a beautiful thing.

How strong is steel? That's a huge question! Basic steel has an ultimate tensile strength of roughly 35,000 psi. (0:

You have to narrow down what questions you have for each project you are working on. Start with a simple project that only requires a few answers to be successful. Learn how to answer those questions. As you continue with more projects you will learn more and more.

There's beam formulas or table that you can use for deflection, etc.

Feel free to post pics or sketches of your design and I can provide opinion on design.

Good luck

 

[PILOON]

I gather you understand wood, well steel is similar.
A 2 x 8 is stiffer than a 4 x 4, well steel is similar.
Like wood trusses, steel "I" beams are best for stiffness.
When it comes to posts a square tube is better than a flat bar, just like a 2 x 4 makes a better post than a 1 x 6.
Steel will not rot but it rusts

Not realized by many but lengths of steel I beams also flex and like wood joists also need legs at intervals.

Probably the main advantages is joints can be welded and longevity is better also dimensions are lesser for same strength.

Once we made a very successful drag using wood 6 x 6's bolted together that lasted over 10 years, it was faced with 3/8 X 4" 'cutting edges'. It was later replaced with 4" angle steel similar structure. Both did an equally good job of grading our road.
The steel one was stolen for scrap value within a year but they never touched the wooden drag.

Trust the steel supplier as he will have a general good idea as to what is required for most cases.

Available are handbooks that will provide all the basic info such as PSI, etc for most dimensions available.

 

[PapaPerk]

I'm guessing but I will go out on a limb say that if you asked a current structural engineering student...They'd say yes they had to learn the theory behind typical design calculations and all the required math-algebra/calculus etc...but these days you just type in all the variables into software programs and it spits out everything you want/need...including supplemental (after install) bracing placement etc...

I don't think it's quite that easy.

You can fly a plane on auto pilot but it still takes a real pilot to land. In other words you must know the theory, etc to understand the results and check for accuracy.

 

[CNC Dan]

Look for a free program called "beam boy". It has been a while since I've had a computor at home, but I remember that you could select shapes from a list, choose your length and where the loads and supports are placed, and it would give you the deflection, and peek stress amount and location.

If you have a smart phone, the App"epic FEM" is simmilar.

 

[bertsmobile]

I don't think it's quite that easy.

You can fly a plane on auto pilot but it still takes a real pilot to land. In other words you must know the theory, etc to understand the results and check for accuracy.

yep,
Like plowing a field there is a lot more to it than trying to drive in a strait line.

Being a metallurgist in a previous life I would rate the question similar to
" how strong is a piece of wood"
There are over 100 grades of plain carbon steel to start with.
The ASTM Used to put out a "handbook" it was 13 thick volumes.
For a wood worker the hardest to get your mind around is wrought steel works best in tension which is opposite to timber which works best in compression.
Cast steels works best in compression.
Like timber all the tables & data sheets reffer to a "theoretical " flaw free length of steel without any nicks, scratches and bolt holes/ welds.
Weldds are castings and need to be in compression is at all possible and if that is not possible than shear.

To get the general feeling about span lengths and loads go to one of the pallet racking suppliers and look through their brochures.
Dexion for example make beams in C channel, U channel I beam & boxed beams and all of them are available in a variety of load bearing capacities.
FWIW I buy old Dexion beams which i can get for scrap prices then cut the mounting ends off.
So I know the 14' long 6 x 2 boxed beam is good for 3 ton.
It is a lot cheaper than buying new steel.

 

[muddstopper]

Long spans with steel are difficult if you dont know the rules. I bought a portable barn from a guy that thought he would add a loft using 6in channel. The span was 24ft. The channel sagged under its own weight. The barn was only about 3 months old and i bought it for a song because he found out the hard way that what he had envisioned wouldnt work. I still havent figured out what he had in mine, the cross beams ( the thin galvanized sq tubing those carports are built with) where only held up with 1/4 in self tapping screws, even if the channel hadnt of sagged, the whole structure would have probably collasped in a good wind storm.