. The American florist : a weekly journal for the trade. Floriculture; Florists. Pig. Greenhouse Construction. ,—Truss section of 150-foot house. only to carry the weight of the glass which is less than two pounds per foot. Adding two and one-half pounds per square foot, to cover the weight of the glass and bars, we have 10 pounds per square foot as the total working load for the truss. Suppos- ing the posts are spaced eight feet four inches apart, lengthwise of the house, then each truss has to carry a total working load of 8 1-3 x 28 x 10 pounds, or 2,333 pounds. This loading may be consider
. The American florist : a weekly journal for the trade. Floriculture; Florists. Pig. Greenhouse Construction. ,—Truss section of 150-foot house. only to carry the weight of the glass which is less than two pounds per foot. Adding two and one-half pounds per square foot, to cover the weight of the glass and bars, we have 10 pounds per square foot as the total working load for the truss. Suppos- ing the posts are spaced eight feet four inches apart, lengthwise of the house, then each truss has to carry a total working load of 8 1-3 x 28 x 10 pounds, or 2,333 pounds. This loading may be considered as being distributed at the joints and the ends of the truss, as. Greenhouse Construction. -Stress diagram for truss in figure .5. shown in Fig. V. The stress or strains- produced in the members of the truss can now be determined by means of the device known as the stress or strain dia- gram. The stress diagram for the truss we are considering is shown by Fig. VI. It will be noticed that the lines in Fig. VI are drawn to a scale of 333 pounds to one inch, and they are all parallel tc« one or other of the lines in the truss shown in Fig. V. Without attempting further explanation it may be stated' that the length of each line in Fig. VI represents the number of pounds strain or stress in the corresoonding member of the truss. For instance, the line K. B. in Fig. VI is parallel to the lines be- tween B. K. on Fig. V, that is the upper member of the truss or the sash bar be- tween the two lower purlins. The line B. K. is inches long and as one inch on this diagram represents 333 pounds the stress or strain in the sash bar is 3,200 pounds. In the same way the stress in the lov/er truss rod is found to» be 3,000 pounds. After finding in this way the strain ir> each member of the truss calculations must be made to obtain the correct size for each. For instance, if the sash bar is of cypress then it must be heavy enough to stand a working end strait> of 3,200 po
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectfloriculture, bookyea
