how to calculate the load a car ramp can take

[MoreWellie]

I am looking at making longer ramps where the slope is detachable and wondered if anyone tell me simply how to work out how much weight the slope could take

I am thinking of making ladders out of 50x50mmx6mm angle with 5mm cross flat cross braces out of tread plate (because I have these) I would also have to add some smaller angle across between the two rails every so many tread plates to give some additional strength or even make all of the cross braces out of say 25x25mmx3mm

If I made a straight ladder frame about 1.8m long is it a simple calculation to work out what the maximum weight I could put on the middle if it was supported only at the ends?

would it make a difference to the maximum weight if the angle was up or down?

I could obviously go belt and braces and make a support frame but that makes for storage issues when not in use so I wondered what the capacity would be without the frame

 

[octo0072000]

better off with angle on the tread plates 3mm thick plenty good enough

 

[MoreWellie]

angle was up or down

by this I meant the side pieces of the ladder itself NOT whether the whole ramp sloped up or down

 

[octo0072000]

on the treads the V of the angle up bottom of ramp like this L

 

[MoreWellie]

thanks octo, I would have done it that way. I was actually trying to clarify my original post where I was asking whether it makes a difference to the load capacity if the angle pieces that run up the side of the ramp area are edge up or edge down. when I mentioned 25x25x3mm for the cross braces I knew I meant angle I just didn't think to say it.

edge up has the benefit of making it less likely to drive off the side of the ramp but edge down has the benefit of more clearance for spoilers on the ramp. Like your picture most people use edge up for the side rails but I wondered if it made a difference to the load capacity

 

[octo0072000]

not sure on that
Google is your friend

https://www.google.co.uk/search?q=h...=G59VVu67N8fSUamDlaAH#q=how+to+make+car+ramps

 

[colnerov]

Hi, If the angle is edge up the bending motion is trying to compress it, if it's down it's trying to stretch it. It's easier to stretch than to compress. So edge up.

Colin