Hey guys i need a little help from some of the engineers or guys more experienced in this particular area. I'm building a gantry lift in my new shop that will be fixed on one end with a pivot and have a base with wheels on the other to swing across approximately two thirds of my shop floor. Most of what i do is lifting sbc engines and things of that size and weight range. I have aquired a beam from work and am trying to do the math to see if it fits my needs. But I'm a little out of my league figuring the point load capability of this beam. the span will be 28ft or less. The beam is a w8-21 i don't know its exact make up outside of dimensions. It originally held a sign up on a state hwy. Thanks in advance
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Gantry hoist calculations
- Thread starter Jking24
- Start date
laser3kw
Well-known member
w8-21 =
Nominal Size
8 x 5 1/4 in
Weight per Ft.
21 lb
Depth of Section
8.28 in
Flange Width
5.270 in
Web Thickness
0.250 in
Online beam calculator (general beam - not w8-21)
W beam calculator click here
"kips" = 1 kip = 1000 lb
I calculated the beam, supported each end, 2 kip (2000 lb) load in center and at 90° (straight down) will deflect 5.45"
That does not include any twisting moment along axis
Nominal Size
8 x 5 1/4 in
Weight per Ft.
21 lb
Depth of Section
8.28 in
Flange Width
5.270 in
Web Thickness
0.250 in
Online beam calculator (general beam - not w8-21)
W beam calculator click here
"kips" = 1 kip = 1000 lb
I calculated the beam, supported each end, 2 kip (2000 lb) load in center and at 90° (straight down) will deflect 5.45"
That does not include any twisting moment along axis
Last edited:
laser3kw
Well-known member
I am kind of scratching my head on that deflection - just doesn't seem right.
I am trying other calculators to see if they support that number. I get the impression the typical beam and young's modulus is for an "H" beam.
Also, the Idea of "lifting" is dead lift like object from the floor. You also can impart a greater force if the object is stuck and you have to apply extra force to get it to move.
I am trying other calculators to see if they support that number. I get the impression the typical beam and young's modulus is for an "H" beam.
Also, the Idea of "lifting" is dead lift like object from the floor. You also can impart a greater force if the object is stuck and you have to apply extra force to get it to move.
nadogail
Well-known member
Some years ago, maybe 20, I had a catalog from Wallace Gantry Cranes that specked out the steel they used. I gave it to a guy who was a fabricator and wanted to put together a crane for his shop.
laser3kw
Well-known member
Thankyou for the info is their a max allowable or recommended deflection for that particular size beam at that length. I'm sure I'll never lift over 1000 lbs.
as far as a maximum allowable, there will be a yield point to where the deflection will not recover once the load is removed.
you could improve the load deflection number by welding "fish plate" gussets (both sides) with plug weld holes through the center 10 feet of the span.
Renegade1LI
Well-known member
What about looking at gantry manufactures & see what they are using. Sorry 472scout, didn't see your post, great info.
matt_i
Well-known member
If the W8 * 21#/ft beam deflects 5.45" there's a serious problem...
You should shoot for L/360 deflection so over 28' x 12"/ft = 0.93"
Then you have to solve the (delta max) = WL^3/48EIxx, for W
W = 48EIxx*(delta max)/L^3 ~~ = 2600#.
Good safety factor of 2 to lift 1000 lbs.
Usual comments apply about making the columns moment-bearing, not too skinny for the height, appropriate connection between columns and beam, and you have to rig a ~600 lb piece of steel over your head to land on the columns and match bolt hole locations.
You should shoot for L/360 deflection so over 28' x 12"/ft = 0.93"
Then you have to solve the (delta max) = WL^3/48EIxx, for W
W = 48EIxx*(delta max)/L^3 ~~ = 2600#.
Good safety factor of 2 to lift 1000 lbs.
Usual comments apply about making the columns moment-bearing, not too skinny for the height, appropriate connection between columns and beam, and you have to rig a ~600 lb piece of steel over your head to land on the columns and match bolt hole locations.
bczygan
Well-known member
Maximum deflection will be .362"
Bill
Bill
TTMotorsports
Well-known member
Harrington Hoists and Cranes lists their sizing chart for bridge beams which may help as well.
The link below is to download the PDF for it
https://www.google.com/url?sa=t&rct...%20rev02.pdf&usg=AOvVaw04VI52wYTURKmkV_5TtOmU
The link below is to download the PDF for it
https://www.google.com/url?sa=t&rct...%20rev02.pdf&usg=AOvVaw04VI52wYTURKmkV_5TtOmU
If the W8 * 21#/ft beam deflects 5.45" there's a serious problem...
You should shoot for L/360 deflection so over 28' x 12"/ft = 0.93"
Then you have to solve the (delta max) = WL^3/48EIxx, for W
W = 48EIxx*(delta max)/L^3 ~~ = 2600#.
Good safety factor of 2 to lift 1000 lbs.
Usual comments apply about making the columns moment-bearing, not too skinny for the height, appropriate connection between columns and beam, and you have to rig a ~600 lb piece of steel over your head to land on the columns and match bolt hole locations.
Thanks for your help Setting the beam will not be a problem. I have a bobcat and a fork lift. So if I followed your response correctly the beam is plenty adequate for my desired use correct ?
matt_i
Well-known member
Yes, from what you describe, SBC engines would fall right inline. It would be good to print a big label/decal/sticker with the 1000# working capacity.
There are other parts to it as well, what are your plans for the columns?
There are other parts to it as well, what are your plans for the columns?
If the W8 * 21#/ft beam deflects 5.45" there's a serious problem...
You should shoot for L/360 deflection so over 28' x 12"/ft = 0.93"
Then you have to solve the (delta max) = WL^3/48EIxx, for W
W = 48EIxx*(delta max)/L^3 ~~ = 2600#.
Good safety factor of 2 to lift 1000 lbs.
Usual comments apply about making the columns moment-bearing, not too skinny for the height, appropriate connection between columns and beam, and you have to rig a ~600 lb piece of steel over your head to land on the columns and match bolt hole locations.
Yes, from what you describe, SBC engines would fall right inline. It would be good to print a big label/decal/sticker with the 1000# working capacity.
There are other parts to it as well, what are your plans for the columns?
Thanks. I have some other box steel at work I'm gonna re purpose. And make a T base or A frame aswell as a gusset at the connecting point. All of the material I have for that is way over kill. So I don't have any concerns their. One side will be fixed with a pivot and the other will be the A-frame or t base with 4 600# casters. Is their a central rule of thumb for base width vs hieght for stability. It will be in the range of 12ft high. I was thinking the base needed to be around 5-6' wide on the side that moves
TheWanderer
Well-known member
Harrington Hoists and Cranes lists their sizing chart for bridge beams which may help as well.
The link below is to download the PDF for it
Hey guys i need a little help from some of the engineers or guys more experienced in this particular area. I'm building a gantry lift in my new shop that will be fixed on one end with a pivot and have a base with wheels on the other to swing across approximately two thirds of my shop floor. Most of what i do is lifting sbc engines and things of that size and weight range. I have aquired a beam from work and am trying to do the math to see if it fits my needs. But I'm a little out of my league figuring the point load capability of this beam. the span will be 28ft or less. The beam is a w8-21 i don't know its exact make up outside of dimensions. It originally held a sign up on a state hwy. Thanks in advance
What contraption did you end up going with?
nadogail
Well-known member
An "Old Timer" gave me some words to live by; "When In Doubt; Build It Stout"
His creations never failed, because he built them Stout.
His creations never failed, because he built them Stout.