Dragon Portland Cement

Dragon Portland Cement

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1910 edition. Excerpt: ...in the case supposed above will be l%x4-50:675. From the table for a 700 pound load it is seen that a beam l8 inches deep will be safe on a span of l 5.8 feet while for a 600 pound load the span is l7.0. By proportion, a 675 pound load would be safe on a l6.7 foot span. Probablyabeam l7 inches deep would be about right, but l8 inches is a better size because lumber can be secured of a width to build the forms for V such a beam without ripping. It is seen that the beam 6x20 takes less concrete material than the one even Bxl 7, so that it is evident the deeper it is possible to make a beam the less it will cost within certain practical limits. WIDE BEAMS.--lf the depth of a beam is limited, then its width must of course exceed what have thus far been considered good practical widths. Suppose for example that the depth of the beam in the previous example cannot for some reason be greater in vertical dimension than l2 inches. According to the table this depth and a l6 foot span falls between a 200 and a 250 pound load, one having a span of l6.3 and the other of l5.5. By proportion the actual load for just a l6 foot span can be found to be 23 l pounds. Since a load of 450 pounds per foot has to be carried, the width of beam required will be as many times I2 inches (the width of beam in the table) as 450 is times Z3l. 450%-Z3l = l.95. l.95xlZ=23.4. With a beam almost 24 inches wide the rods are spaced further apart than really necessary if comparatively large diameters are employed. Consequently an engineer under such conditions would probably put them so that they were not more than two diameters apart in the clear, grouped at the center of the bottom of the beam, and would then cut away the concrete on the two lower comers, so as to make the...show more

Product details

  • Paperback | 36 pages
  • 189 x 246 x 2mm | 82g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236810392
  • 9781236810397