

Subject:
bending strength of rectangular steel
Category: Science > Instruments and Methods Asked by: usajohnsonga List Price: $25.00 
Posted:
06 May 2006 11:56 PDT
Expires: 05 Jun 2006 11:56 PDT Question ID: 726101 
I need to build a set of ramps for my dump trailer. The ramps will be 6' long. I have and want to use 1" x 3" 11 gauge rectangular steel. If I were to take one 6' piece of this material, stand it on its' narrowest edge, support it at both ends and place a load at its' center how much weight will it suppurt before failing. A little deflection is allright just so it does not permanently bend. 

Subject:
Re: bending strength of rectangular steel
Answered By: redhossga on 06 May 2006 16:13 PDT Rated: 
Hello usajohnson, I think I can help you. I searched for properties of 1" x 3" 11 gauge rectangular steel tubing, but that is an odd size. We will have to calculate the section modulus (excluding corner radius): S = bd^3  b1d1^3/6d b = 1" d = 3" b1 = 1  2x0.091 = 0.818 d1 = 3  2x0.091 = 2.818 S = [(1 x 3^3)  (0.818 x 2.818^3)] / (6 x 3) = 0.483 in^3 M (maximum bending moment) = [P (point load) x l (length)] / 4 Solving for P: P = 4M/l M = s x S Where: s (allowable bending stress) = .55 x yield strength of steel To be conservative we will assume that the steel you have is 30,000 psi M = .55 x 30,000 x 0.483 = 7,969 inlb P = 4 x 7,969 / 72 in = 442# So, you can say that the tubing will safely support at least 442#. The tubing you have may actually be as high as 50,000 psi yield strength, but we don't really know. Please ask for a clarification if there is any of this that you don't understand. Good luck with your project, Redhoss  
 
 
 
 
 

usajohnsonga
rated this answer:
This was just the information Iwas looking for. Thia is a very usefull forum. 

There are no comments at this time. 
If you feel that you have found inappropriate content, please let us know by emailing us at answerssupport@google.com with the question ID listed above. Thank you. 
Search Google Answers for 
Google Home  Answers FAQ  Terms of Service  Privacy Policy 