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Q: SIZING AN I BEAM TO SPAN 14 FEET ( Answered ,   0 Comments )
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 Subject: SIZING AN I BEAM TO SPAN 14 FEET Category: Science > Physics Asked by: goose1027-ga List Price: \$50.00 Posted: 17 May 2006 12:45 PDT Expires: 16 Jun 2006 12:45 PDT Question ID: 729814
 ```I am making an addition to my kitchen which will result in a 14 foot load bear- ing wall being removed. This wall supports a second story. Using info from another website I have calculated the weight on this beam to be 1200 pounds per linear foot. What size I beam do I need to support this load? I would like to limit the depth to 12 inches or less. Thank you, J. R.```
 ```Hello J. R., you have done the hardest part of the calculations by providing the load applied to the beam. I can help you with the rest. The beam formulas for this loading are: M (maximum bending moment) = wl^2/8 D (deflection @ center of span) = 5wl^4/384 EI NOTE: Maximum deflection is limited to D = l/360 = 14 x 12 / 360 = 0.46 in w (load per foot) = 1200 lb per ft l (beam span) = 14 ft Where E is a constant for steel = 30,000,000 psi And I is the moment of inertia Solving for M: M = 1200 x 14^2 / 8 = 29,400 ft lb = 352,800 in lb The allowable bending stress for structural steel (s) = 0.55 x 36,000 psi = 19,800 psi The section modulus of the required beam (S) = M/s = 352,800/19,800 = 17.8 in^3 Now we must calculate the required I (moment of inertia): Solving for I in the above formula for deflection we get: I = 5wl^4/384 ED = (5 x 1200 x 14^4 / 384 x 30,000,000 x 0.46) x 1728 NOTE: 1728 is a conversion factor to get the proper units for I I = 75.2 in^4 Now we can look for a beam with these minimum properties and a maximum depth of 12 inches. A good choice would be a 10.25 inch deep Wide Flange beam weighing 19 # per ft (W10x19) S = 18.8 in^3 I = 96.3 in^4 Of course, you can use a heavier beam if there is one more available. Please ask for a clarification if there is anything you don't understand and I will try to explain. Good luck with your kitchen project, Redhoss``` Request for Answer Clarification by goose1027-ga on 19 May 2006 16:32 PDT ```Thanks for your prompt reply Redhoss. To satisfy my curiosity, what is the flange width, flange thickness, and web thickness of the W10x19 beam? Thank you, J. R.``` Clarification of Answer by redhoss-ga on 20 May 2006 06:21 PDT ```Thanks for the tip. Here is what you need: Flange width: 4.020" Flange thickness: 0.394" Web thickness: 0.25" If you have another beam you would rather use, I will be glad to check it out for you.``` Request for Answer Clarification by goose1027-ga on 25 May 2006 18:05 PDT ```Thanks for the clarification, Redhoss. I do have another question. I had planned to support this beam on each end with a 6x6 wooden post. Since the beam is only 4 inches wide, I thought of using two metal posts. What size metal posts would I need to support this load? I can use either round or square. Since this isn't a clarification of the original question, do I need to go through the process and ask as a new question? Thanks, J. R.``` Clarification of Answer by redhoss-ga on 26 May 2006 06:05 PDT ```The reaction at each end of the beam is: 14 x 1200/2 = 8400# The bearing area on the 6x6 is: A = 4 x 6 = 24 sq in So, the pressure in the wood would be: p = 8400/24 = 350 psi (this is much less than allowable compressive strength) I see no problem in using the 6x6 wood columns that you planned to use. It will certainly make nailing much easier. However, if you want to use steel, how about a 4 inch square light gauge tube. If you can get 14 ga., it would work just fine.```
 goose1027-ga rated this answer: and gave an additional tip of: \$10.00 ```Very prompt and professional reply. I requested the same info from another website 2 months ago and still haven't heard from them. Thanks, J. R.```