. American engineer and railroad journal . pullingand buffing stresses. The car is 8 feet 6 inches wide over theside sills and has a total tloor space of 330 square feet, whichwill accommodate a load of 60,000 pounds. Mr. Vaughan de-scribes the design in the following words: The general design is shown by Fig. 1, and It will be seenthat the truss is of the ordinary N type, with posts In com-pression. The transoms are 30 feet centers, and the lloor iscan Jed by four beams at the panel points, which are spacedabout 6 feet apart. Each of these lloor beams would carry aload of 9,300 pounds if the
. American engineer and railroad journal . pullingand buffing stresses. The car is 8 feet 6 inches wide over theside sills and has a total tloor space of 330 square feet, whichwill accommodate a load of 60,000 pounds. Mr. Vaughan de-scribes the design in the following words: The general design is shown by Fig. 1, and It will be seenthat the truss is of the ordinary N type, with posts In com-pression. The transoms are 30 feet centers, and the lloor iscan Jed by four beams at the panel points, which are spacedabout 6 feet apart. Each of these lloor beams would carry aload of 9,300 pounds if the load were uniformly distributed, butI consider that the possibility of heavy local loading must betaken into account, and for this I have allowed a double load of18,000 pounds on one floor beam, but under these circumstanceshave taken the load on the adjacent floor beams at 4,700pounds, making as before a total of 28,000 pounds for threebeams. I believe that such an assumption will be found to -Lfnilormly ObtribultJ Load Concentro?^ Laod-. Fig. 2-Stress Diagram. meet all cases that will be encountered in practice, as no ma-chineiT or metal will be loaded that would give rise to greaterlocal weights. The diagram Fig. 2 shows the stresses on the framing, theleft-hand side being for a uniformly distributed load and theright-hand side for a load concentrated as above described, butsymmetrical with respect to the center. The weight of theframe sheathing, roof, etc., is included. The allowable stressesin the various members are taken as follows: On framing, 12,500 pounds per square inch for tension, 8,000pounds per square inch for compression. On rivets, 7,500 pounds for shearing, 15,000 pounds per squareincli for bearing. By reference to Fig. 1 it will be seen that the posts andbraces are made of 3-inch channel, 5 pounds per foot, and themaximum stress will be 10,000 pounds for tension and 6,800for compression. The transom post is a 5-inch channel, pounds per foot, and the stress
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