Steel strength charts

Jan 31, 2011 6 Replies

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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Flickr of ideas ....................

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Machinery's Handbook?

Good Luck! Rich

peak point of attachment

tched to the roofing,

Most of that sort of thing is found in second and third year ME texts as student problems. Get the solution guide. Also engineering mechanics under statics.

Stan

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

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

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

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