Steel strength charts

I'm building a lift, probably 1,000 $ max, but mostly 500 or less. Is there a chart that gives different structural configurations and their relative efficiencies?

i.e. .............. a bar joist design a pyramid with lifting point at the apex two poles with a right angle peak point of attachment and one horizontal purlin a plain truss shaped span, pitched to the roofing, with diagonal bracing ............

16' wide span, verticals 8', then up with the framework. I actually need two so I can lift my boat entirely with straps. Weight of boat, about 1500#.

I have been googling, but no luck yet.

Material would be 3 x 3 x .120" tubing MIG welded together, and gusseted mostly wherever possible, and lateral bracing to help side loading.

TIA

Steve

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Reply to
Steve B
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Flickr of ideas ....................

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Reply to
Steve B

Machinery's Handbook?

Good Luck! Rich

Reply to
Rich Grise

peak point of attachment

tched to the roofing,

Stan

Reply to
stans4

In my day, these excercises used to work on paper but rarely in the real world. The values for Youngs Modulus and maximum stress are all given in the question and may not be realistic. Also don't forget to consider the stress in the welds, esp[ecially end effects. If possible, design so the welds are not stressed by the load or are in compression. Finally, proof load the finished structure.

John

Reply to
John

In my day, these excercises used to work on paper but rarely in the real world. The values for Youngs Modulus and maximum stress are all given in the question and may not be realistic. Also don't forget to consider the stress in the welds, esp[ecially end effects. If possible, design so the welds are not stressed by the load or are in compression. Finally, proof load the finished structure.

John

I am going to fishplate most of the connections, too. That should improve it greatly. Without totally using destructive testing, I think it will handle the load I want.

Steve

Reply to
Steve B

I test beams for deflection by clamping two together with spacer blocks at the ends and pulling them together in the middle. The best truss design:

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jsw

Reply to
Jim Wilkins

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