garage conversion help
Discussion
advice needed for a steel , girder or RSJ.
for the above drawing (guide only) What size ( thickness ) of RSJ would be needed to support a 1 ton weight.
width between walls 2600mm
Ie : lift the car 2m of the ground ( weight of car is approx 450kg ) However thought 1 ton RSJ would give a good safety margin
Is there a formulae for working this out
cheers
for the above drawing (guide only) What size ( thickness ) of RSJ would be needed to support a 1 ton weight.
width between walls 2600mm
Ie : lift the car 2m of the ground ( weight of car is approx 450kg ) However thought 1 ton RSJ would give a good safety margin
Is there a formulae for working this out
cheers
Are you lifting the car of one beam or a pair? Do you want to apply the 1 tonne to the centre of the beam?
If so the Bending Momment is equal to WL/4 use kN and M as your units, Bending Momment=fz where f is the stress in the beam, z is the elastic modulus about the x-x axis.
If you multiply the BM by 10 pow6 and then divide by say 140N/mm2 that will give you an approximate section sizes z value, you need to check the Corus UB, UC of Joist information.
Load is 450kg = 4.5kN
Mnt = (4.5*2.8)/4 = 3.1kNm
(3.1*10^6)/140 = 22072 mm^3
Choose a 127*76*13 UB z=76cm^3 = 76000mm^3 > 22072mm^3
You would also need to check the shear, deflection and web buckling. I haven't got BS 449 at home so cannot check it, but I am pretty sure that the beam would kill it.
You also need to check the bearing of the beam on the brickwork and a few other things, worth getting someone to do some proper cals, but that should give you a rough idea.
If so the Bending Momment is equal to WL/4 use kN and M as your units, Bending Momment=fz where f is the stress in the beam, z is the elastic modulus about the x-x axis.
If you multiply the BM by 10 pow6 and then divide by say 140N/mm2 that will give you an approximate section sizes z value, you need to check the Corus UB, UC of Joist information.
Load is 450kg = 4.5kN
Mnt = (4.5*2.8)/4 = 3.1kNm
(3.1*10^6)/140 = 22072 mm^3
Choose a 127*76*13 UB z=76cm^3 = 76000mm^3 > 22072mm^3
You would also need to check the shear, deflection and web buckling. I haven't got BS 449 at home so cannot check it, but I am pretty sure that the beam would kill it.
You also need to check the bearing of the beam on the brickwork and a few other things, worth getting someone to do some proper cals, but that should give you a rough idea.
I have to ask, although I'm probably missing something obvious:
You have enough height to lift a car 2m off the ground, so you have enough height for a lift. Why not use a two post or scissor lift? If you sink the base into the ground to make the lift flush they really aren't in the way, plus the RSJ ceases to become an issue.
BTW, I don't know your background but if you've never had a lift you have no idea just how easy they make things.
You have enough height to lift a car 2m off the ground, so you have enough height for a lift. Why not use a two post or scissor lift? If you sink the base into the ground to make the lift flush they really aren't in the way, plus the RSJ ceases to become an issue.
BTW, I don't know your background but if you've never had a lift you have no idea just how easy they make things.
BB-Q said:
I have to ask, although I'm probably missing something obvious:
You have enough height to lift a car 2m off the ground, so you have enough height for a lift. Why not use a two post or scissor lift? If you sink the base into the ground to make the lift flush they really aren't in the way, plus the RSJ ceases to become an issue.
BTW, I don't know your background but if you've never had a lift you have no idea just how easy they make things.
the idea is to lift the Lotus which weighs 450kg to ceiling height around 3.6m high , car would be around 2m minimum off the ground ,You have enough height to lift a car 2m off the ground, so you have enough height for a lift. Why not use a two post or scissor lift? If you sink the base into the ground to make the lift flush they really aren't in the way, plus the RSJ ceases to become an issue.
BTW, I don't know your background but if you've never had a lift you have no idea just how easy they make things.
Either with two beams or a single beam could be used to support two / one 1ton chain hoists either lift the car on the roll bar or on a metal frame suspended by 4 corner lifting points.
There is not enough room for a scissor/ lift...........actualy its the missus Utility room !! and she wants tyo get to use the washing machine !!!
cheers
I would use a pair of beams as this will make the lifting a bit easier, if you need to make a frame for the car to be lifted from the corner then due to the height length of chains they would probably not be at the best angle, although the weight you are lifting is minimal.
So two beams with a single chain block picking up a frame under the car, two leg chain at the front and two at the back. You could probably make the frame out of a pair of parallel flange channels, with a bit of steel between them front middle & back. You will need a bit of bracing to keep it rigid, sounds an interesting project!
So two beams with a single chain block picking up a frame under the car, two leg chain at the front and two at the back. You could probably make the frame out of a pair of parallel flange channels, with a bit of steel between them front middle & back. You will need a bit of bracing to keep it rigid, sounds an interesting project!
ALawson said:
I would use a pair of beams as this will make the lifting a bit easier, if you need to make a frame for the car to be lifted from the corner then due to the height length of chains they would probably not be at the best angle, although the weight you are lifting is minimal.
So two beams with a single chain block picking up a frame under the car, two leg chain at the front and two at the back. You could probably make the frame out of a pair of parallel flange channels, with a bit of steel between them front middle & back. You will need a bit of bracing to keep it rigid, sounds an interesting project!
had an idea along these lines I can weld So it would be no problem to fabricate the skid frameSo two beams with a single chain block picking up a frame under the car, two leg chain at the front and two at the back. You could probably make the frame out of a pair of parallel flange channels, with a bit of steel between them front middle & back. You will need a bit of bracing to keep it rigid, sounds an interesting project!
thamks for the info .........I originaly looked into single phase 4 post garage lifts / scissor lifts etc. missus has put her foot down she wants the car etc out of site !!!
The only problem with lifting it off a pair of two leg chains is that the centre of gravity needs to be pretty central other wise the frame will hang at an angle. With 4 individual chain blocks you will be able to adjust the position of the car a bit better. You could always do a trial lift and then use some weights on the frame to get the balance perfect.
With 4 legs you also have a bit of redundancy if one were to fail!!!
With 4 legs you also have a bit of redundancy if one were to fail!!!
Rather than picking it up from a central point and putting the weight on the centre of an RSJ, the loads will be massively reduced if you pick it up from four points because you're applying far less bending moment on the RSJ. Taken to the extremes (not that it is really practical, but to demonstrate the point) if you had four winches each attached to the RSJ right out by the wall, there would be no load on the RSJ at all.
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