I-Beams

[Kubota_Man]

Does anyone know how to figure how to calculate the size of I-Beam I would need to span 12' and support 1500lbs in the center with no overhead bracing? I am not too concerned with metal type just don't want to spend more than I have to.

 

[Eric McCarthy]

What exactly is it you're trying to accomplish with an I-beam over a 12 foot span?

 

[Dennis T.]

Any of your local fabrication shops have engineers that should be able to answer that. I Just 'over-built' my 30' span bi/fold door to be extra safe. But that's spendy even at cost.

 

[skeets]

Hey Dennis,,, Whats that green thing in your barn???

 

[cabu]

Normal construction steel -> 235(N/mm²)

I-Beam (DIN 1025): Hight 80mm, width 42mm -> Wx=19500(mm³)

Example:

4 meters long and supported at the ends, load in the middle.

Fmax=([Steeltyp]*4*Wx)/l

Fmax= (235(N/mm²)*4*19500(mm³))/4000(mm) = 4582.5 N

Maximum weight in the middle = 4582.5 (N)/9,81 (m/s²) = 467 kg

Questions?

der carl

ps
You need the shape of the I-beam to get the value of the Wx and the type of steel for the strength (N/mm²)

I am just a german engineer and I don't know the american I-beam standarts...

What I have found is:

12' -> 3,6m
1500lbs -> 683kg


Fmax=([Steeltyp]*4*Wx)/l

weight*g*l/4/[Steeltyp]=Wx

Wx= 683kg*9,81[m/s²)*3600mm*4*235[N/mm²)
Wx= 22673[mm³]

-> I-Beam standart size minimum IPE100: 100mm x 55mm (32000[mm³])

I-Beam

 

[skeets]

CABU thats pretty indepth,, now if you would please put that in to coal miner talk

 

[cabu]

CABU thats pretty indepth,, now if you would please put that in to coal miner talk

Open a beer, wait a little bit and try again. It is high-school stuff. You only have to understand that the shape (Wx) and the way it's stressed is importend.

 

[Dennis T.]

Hey Dennis,,, Whats that green thing in your barn???

Someone must have 'over engineered' the Kubota paint formula.

 

[Kubota_Man]

What exactly is it you're trying to accomplish with an I-beam over a 12 foot span?

I want to be able to span center rafter to garage door and put a rolling hoist on it. Both front and center rafters have a 2000 lbs pick points. I hope to be able to use the that span at any point inbetween.

--------------------------------------------------------------------------------
Normal construction steel -> 235(N/mm²)

I-Beam (DIN 1025): Hight 80mm, width 42mm -> Wx=19500(mm³)

Example:

4 meters long and supported at the ends, load in the middle.

Fmax=([Steeltyp]*4*Wx)/l

Fmax= (235(N/mm²)*4*19500(mm³))/4000(mm) = 4582.5 N

Maximum weight in the middle = 4582.5 (N)/9,81 (m/s²) = 467 kg

Questions?

der carl

ps
You need the shape of the I-beam to get the value of the Wx and the type of steel for the strength (N/mm²)

I am just a german engineer and I don't know the american I-beam standarts...

What I have found is:

12' -> 3,6m
1500lbs -> 683kg


Fmax=([Steeltyp]*4*Wx)/l

weight*g*l/4/[Steeltyp]=Wx

Wx= 683kg*9,81[m/s²)*3600mm*4*235[N/mm²)
Wx= 22673[mm³]

-> I-Beam standart size minimum IPE100: 100mm x 55mm (32000[mm³])

What did you just say????????? I reconize that there is english and numbers in this, however can you explain this in a language that a hard rock miner and an Army guy can understand please

 

[Eric McCarthy]

I helped a neighbor put 12'' tall I-beam in his barn that was about 12-15 feet wide and he put a hoist on his beam and lifted up all sorts of stuff...

 

[Dennis T.]

I think I know now where Cabu is coming from ....


http://www.youtube.com/watch?feature=player_embedded&v=nd5WGLWNllA#!

 

[Kytim]

Hey Dennis,,, Whats that green thing in your barn???

Awe, his tractor is molding!! It must be really lonely.

Kytim

 

[smog]

Normal construction steel -> 235(N/mm²)

I-Beam (DIN 1025): Hight 80mm, width 42mm -> Wx=19500(mm³)

Example:

4 meters long and supported at the ends, load in the middle.

Fmax=([Steeltyp]*4*Wx)/l

Fmax= (235(N/mm²)*4*19500(mm³))/4000(mm) = 4582.5 N

Maximum weight in the middle = 4582.5 (N)/9,81 (m/s²) = 467 kg

I-Beam

THANK YOU, was looking for that formula.

 

[skeets]

YA know I love engineers really I do. They are some of the most friendly help you out of a jam kind of guys I know. One young man in the District Office is a” I hope I have this right “
Geological - Hydriodic Engineer he works with water and earthen dams at mine sites.
A great kid, he hunts, raises field dogs, fishes, and loves his 2 sons to pieces. The only problem with Craig is,, don't ask him what time it is,, cause before you get the answer he tells you how a watch is made and why it works,,

 

[Bulldog]

Don't feel bad Skeets. My Son is in 7th grade and my daughter in 1st. They no longer have simple adding, subtracting, and multiplication any more. They have wierd, strange names for this now. It may work about the same and you end up with the same answer but the process is totally different. Makes me feel dumb. 2+2=4 still works for me but the kids now days seem to go all the way around the world to get the same answer.

 

[cabu]

Don't feel bad Skeets.... Makes me feel dumb. 2+2=4 still works for me ...

But 1+1=1 !

If you dump one sandheap on another you get one. Bigger, but one! Computers calc that way, boolean algebra.

YA know I love engineers really I do....the answer he tells you how a watch is made and why it works,,

They always try to give you the fishing rod instead of the fish. So you don't come a second time with the same kind of question...
And by the way, kubotaman got his answer (only a metric one)

What did you just say????????? I reconize that there is english and numbers in this, however can you explain this in a language that a hard rock miner and an Army guy can understand please

I give you the answer!!

I believe the american construction steel for simpel standart constructions is nearly the same like the germans.
So I gave you the dimensions of the I-Beam you need: 4"x2" with a steel thickness of the middel one (web) of 1/6" and the beam top and button (flange) in 1/4"

At that webpage it looks like it is the I-Beam typ S4x9.5

Have fun and don't walk below hanging tractors...

der carl

 

[Kubota_Man]

Ok I talked to a local engiering firm and he said W8X15 with a 50ksi (what ever that means). How does that compare to what you said of S4x9.5 Cabu????? I'm all confused

 

[cabu]

Ok I talked to a local engiering firm and he said W8X15 with a 50ksi (what ever that means). How does that compare to what you said of S4x9.5 Cabu????? I'm all confused

What I have found:

Strengthness of steal: 50 ksi = 344 N/mm²

Shape W8X15 ~ IPE200 -> Wx=194000 (roughly)

Fmax=([Steeltyp]*4*Wx)/l

Fmax= (344(N/mm²)*4*194000(mm³))/3600(mm) = 74151 N

Maximum weight in the middle = 74151 (N)/9,81 (m/s²) = 7558 kg (16662lbs)

[Weight of the beam would be 80 kg (178lbs)]

The maximum weight of 16662 lbs is when the I-beam starts to bend permanent. The risc-faktor of 11 (16662 / 1500) is maybe a litte bit to much...

Think by your self: 12' and 1500lbs in the middel! That does not need an I-beam of 8" x 4". Imagine how big it is.

My opinion is that you should install an I-beam that bend before a force is damaging your barn. Your supporting points can stand 2x 2000lbs. The I-beam should start to bend below that. It's cheaper to buy a new beam than a new barn. My opinion.

carl

 

[Kubota_Man]

I do agree that something should start to show stress (I-Beam bending) before I reach the max capacity of the building. Although while I am good with math the calculations of how to figure what I need and or should have excapes me. So I need to ask smarter folks like those here on OTT and local folks who are in the know.

So how does S4x9.5 compare to W8X15? Is there a differance as far as Metric and SAE? What is the weight limit on both at the center of a 12' span?

I don't want to see this happen to my Kubota's house

http://nature-photography.ca/photos/palouse-washington-collapsed-barn

 

[cabu]

What I have just found:
S4x9.5
Elastic properties Sx 3.39 in³
Plastic modul Zx 4.04 in³

I guess, elastic will mean it will bend back and plastic will mean the bend will be permanent.

Strengthness of steal: 50 ksi = 344 N/mm²

Shape S4x9.5: Sx 3.39 in³ * 25.4³ -> Wx = 55552 mm³

Fmax=([Steeltyp]*4*Wx)/l

Fmax= (344(N/mm²)*4*55552(mm³))/3600(mm)/9,81(m/s²) = 2164 kg (4770lbs)

Maximum weight in the middle!

[Weight of the beam would be 51 kg (112lbs)]

Your poles can support 2x 2000lbs = 4000lbs -> 1814 kg

There is a problem of 350 kg. Don't damage your barn.

If you take the next smaller I-beam S3x7.5 the Sx is 1.95 in³ and the maximum weight will be 1244kg (2742lbs) and it's weight will be 40kg (89lbs)

The W-shape I-beams are all to strong.(Book of Steel)

Barn 4000lbs
S4x9.5 4770 lbs
S3x7.5 2742 lbs

'Life is like a box of chocolates you never know what you're gonna get'

der carl


ps
I have just checked your answer regarding what you want to do. If you put the load not in the middel but at the end next to the rafter, it shall not be more than the 2000lbs of the supporting point!!