Question

You are to design beams to support formwork for a slab pour. The loads consist of a 75 psf DL and a 50 psf construction load. The beams will be 10-ft long and adequately supported laterally. Assuming a dry service condition, normal temperature, and no incising, at what spacing should a 2x12 of No 2 DF-L be used for these beams? Consider only the bending limit state, use Cr= 1.0, and round down your answer to the nearest 2-in

Answer 1

This question is incomplete, here is the complete question:

You are to design beams to support formwork for a slab pour. The loads consist of a 75 psf DL and a 50 psf construction load. The beams will be 10-ft long and adequately supported laterally. Assuming a dry service condition, normal temperature, and no incising, at what spacing should a 2x12 of No 2 DF-L be used for these beams? Consider only the bending limit state, use Cr= 1.0, and round down your answer to the nearest 2-in.

Also, if the density of the wood is 35 lb/ft3 , what is the weight of the beam in psf?

Step-by-step explanation:

First, you’ll have to multiply the thickness x height x length for the central part of the beam so that you can derive its volume in cubic inches.

Secondly, you’ll have to multiply the thickness x width x length for the top and bottom parts of the beam in separate ways so that you can derive the volume of each in cubic inches.

Thirdly, summation the volume of the three parts of the beam so that you can derive the overall volume in cubic inches.

Fourthly, you will convert the volume to cubic feet and finally multiply the weight density of steel, which will be in pounds per cubic foot, and by the volume to get the weight of the beam in pounds.

Check the attached images to see the full calculation.