40 ft. bridge span-no support in middle?
Question:will four 12" i-beams 1/4" web, two beams will be placed side by side on each side handle a car or a pick-up truck crossing it?
Answers:
The area you live in will provide design criteria for a bridge. In california a residential bridge needs to be designed for HS-20 rating. We recently designed a 62 foot span bridge with three supports. We used 3 continuous steel girders spaced 4'-3" on centers. The girders are W21x68. Your talking about using something in the range of W12x30 through W12x16. Based upon that, and without knowing your design standards, I'd say the beams cannot clear span 40' and be to code. (W12x30 = W shape ((I beam)) 12 = depth x 30 = #/foot ((self weight)))
That's a long bridge for that kind of construction.
Maybe you should run a test with one such beam, placing 1/4 of the weight of the vehicle in the middle for a few days to see what happens to the beam.
not only what the above man said, you have to also think of the emergency trucks like fire trucks that may have to cross that bridge. It is better to get an engineer to answer this question and check with local bridge requirements. Ask your local building department for who you can contact locally to give you this information.
See above answers...check with your local building codes..and how much is your vehicle worth if you are wrong...Or your life...
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