darrendee09
Well-Known Member
any way of finding out what wieght steel will take over a certain distance before breaking?
8"x4"x10mm box
- Thread starter darrendee09
- Start date
JohnBoy
Well-Known Member
ask an engineer?
You might find an appropriate table online, but you might also need at least some engineering qualification to understand them.
My sister's a mechanical engineer, but doesnt do structural stuff so is never able to answer these questions when I ask her. what point is there in having an engineer in the family if they cant answer engineering questions!
You might find an appropriate table online, but you might also need at least some engineering qualification to understand them.
My sister's a mechanical engineer, but doesnt do structural stuff so is never able to answer these questions when I ask her. what point is there in having an engineer in the family if they cant answer engineering questions!
darrendee09
Well-Known Member
banking on it to hold 4.5-5 ton of logs at 20ft, , its well supported so hopefully should be ok,
wdah
Well-Known Member
as a stand or a lifting jib?
Blizzard95
Well-Known Member
Supported at each end is it? or more supports in between?
tinman
Very Senior Member
nick, would you mind answering a question for me, if you could.
i have a beam 20' long, i want to hang 4 tonne at the mid point, its supported on both ends, what size of I beam do i need?
no harm if you cant answer it, but id like to know sometime if i could get an answer.
darrendee09
Well-Known Member
can you do that in solid works? looks bad that i work with solidworks daily lol
much have a search around tomorrow
much have a search around tomorrow
tinman
Very Senior Member
powerfull tool, looks a breeze too.....:whistling:
[ame="http://www.youtube.com/watch?v=6V5k_PHVfqY&list=HL1358983533"]SolidWorks Simulation - Metal Yield Tutorial - YouTube[/ame]
nick
Well-Known Member
http://help.solidworks.com/2013/English/SolidWorks/cosmosxpresshelp/c_Applying_Loads.htm
i think this what i used to check the steel sizes for the gantry in the workshop.
there also a book of tables for it but i cant find it online. if you ring someone who does structural steel they will tell ya for definite
i accept no responsibly for bad advice
i think this what i used to check the steel sizes for the gantry in the workshop.
there also a book of tables for it but i cant find it online. if you ring someone who does structural steel they will tell ya for definite
i accept no responsibly for bad advice
tinman
Very Senior Member
wouldnt ya not need to have solid works for that tho....:whistling:http://help.solidworks.com/2013/English/SolidWorks/cosmosxpresshelp/c_Applying_Loads.htm
i think this what i used to check the steel sizes for the gantry in the workshop.
there also a book of tables for it but i cant find it online. if you ring someone who does structural steel they will tell ya for definite
i accept no responsibly for bad advice
a ball park answer would do me.
darrendee09
Well-Known Member
wouldnt ya not need to have solid works for that tho....:whistling:
a ball park answer would do me.
i find them reusable trials are good
tinman
Very Senior Member
dont be shy with the links like....:Di find them reusable trials are good
nick
Well-Known Member
Last edited:
Lads (and ladies) Please be careful if you dont fully understand how to do these calculations, as the boundary conditions will have a massive effect on the answer.
What i mean by this is :-
how the ends of the beam are fastened,
-pin jointed -(resting on something)
- cantilevered - (one end welded to something)
etc
how the load is applied
- single point load (a bag of fertiliser hanging from the end (or middle) of the beam
- distributed load etc (like stuff even;ly spread on a shelf
Sorry if this is all understood, just that if its not, and someone is calculating beam strength, it can very easily end in failure.
What you are wanting to do, is quite a simple "hand calculation" if you put up what your doing, i can assist.
tinman
Very Senior Member
good man bloders, i do understand your point.
in my case its a crane, the beam sits on top of the traveling unit, so there is no shear factor.
by my reckoning i was going to use a beam 406x140x53, but i might be wrong, altho, id imagine im safe enuf with it, maybe not.
its a 2T crane, which will lift 2.5T, so at 4T i was allowing for a decent safety factor i believe.
as i mentioned earlier, it would have a span of 20', and assuming the highest loading on it would be in the centre and anything else to one side or another would be less stress even if the load remained the same.
there is also the stanchions holding the crane rails up, im very much bound by size here and have little choice but to use 203x133x30, at 16' spacings, either that or i go down the structural route, which is alarmingly expensive.
on the plus side they will only be 12' long and the rails for the crane sit on plinths that would be approximately 7' from the bottom plate so the loading wouldnt be as much as if it was 20' high say.
originally the crane wasnt mounted on anything much stronger tbh,
the rails of the crane are 305x127x37, they originally spanned 20' sections, but i will be using them on 16' spans.
see the pic's to give you an idea what im on about.
any help appreciated.
sorry to have slightly hijacked the thread.
Attachments
Blizzard95
Well-Known Member
I can go. Through it if U want
,will dig up the college notes
good man bloders, i do understand your point.
in my case its a crane, the beam sits on top of the traveling unit, so there is no shear factor.
by my reckoning i was going to use a beam 406x140x53, but i might be wrong, altho, id imagine im safe enuf with it, maybe not.
its a 2T crane, which will lift 2.5T, so at 4T i was allowing for a decent safety factor i believe.
as i mentioned earlier, it would have a span of 20', and assuming the highest loading on it would be in the centre and anything else to one side or another would be less stress even if the load remained the same.
there is also the stanchions holding the crane rails up, im very much bound by size here and have little choice but to use 203x133x30, at 16' spacings, either that or i go down the structural route, which is alarmingly expensive.
on the plus side they will only be 12' long and the rails for the crane sit on plinths that would be approximately 7' from the bottom plate so the loading wouldnt be as much as if it was 20' high say.
originally the crane wasnt mounted on anything much stronger tbh,
the rails of the crane are 305x127x37, they originally spanned 20' sections, but i will be using them on 16' spans.
see the pic's to give you an idea what im on about.
any help appreciated.
sorry to have slightly hijacked the thread.
Crikey, this is going back a bit.
See the attached...
If we treat it as per the bending diagram (ie, the beam is rested at the ends with no addiditonal restraint, the attached calc is true (Blizarrd please check...)
I could not find your particular beam, so i went for a slightly smaller one.
I also applied the load of 2.5 tons, as i prefer tokeep all the margin of safety (and error) toone place.
Providing the inputs I have used are true (please check) then you will be operating at about HALF the yield stress of the beam.
So, in my opinion, your safe.
Attachments
Blizzard95
Well-Known Member
this is my attempt at what you done bloders,only im getting about half the bending stress you got,i cant get the i value you have,so dont no where im gone wrong,fierce all i have forgot in less than a year:D
When we solve this,i have notes on deflection of beams,so can take a quick run through it,
When we solve this,i have notes on deflection of beams,so can take a quick run through it,
Attachments
Have you used the bending eqn if it was welded in at one end and the other end free?
Its years since i did any of this, so i need todouble check.
Dunno why we got different values of I. Ill check at the weekend - early start to Hereford in the morning, and parcel2go havent collected as ordered. Aaaaarrrggh
Sorry
Blizzard95
Well-Known Member
no took it as simply supported at both ends
tinman
Very Senior Member
holy cow lads, i dint mean to put ye to that trouble tbh.
thats a lot of working out.
would it not be safer to calculate for a weight of 4t, so as to allow for nothing ever going wrong?
if ye can calculate the beam, is it possible to see if the 203x133x30 is enuf for the leg supports (the stanchions )
take yer time, this isnt going up any day soon, but id really like to know what the right steel is.
ill take this opportunity to thank ye so far, its much appreciated.
Good News.
Blizzard was right.
Ive put the numbers into a spreadsheet to do the calcs, and I now get the same answer as Blizzard.
This means, for the dimensioned beam we used, there is a factor of safety of 4 and a bit, based on a load of 2.5 tons.
Tinman.
Before you get excited, you need to check the beam dimensions we have used. If you have a look at the pdf I scanned yesterday, i dimensioned it up. Please compare.
Also, you need to be careful how you are hanging the load.
The beam is fine in bending, but need to watch the local stresses on the attachment.
Ill look at the uprights after tea if i can.