Cyclopedia of architecture, carpentry, and building : a general reference work . entrated loads. Since in this case, E^, E^, and the stresses in the knee-braces areless than they are when the columns are free at the base, the windstresses throughout the truss will be less when the columns are fixedthan when they are free. On account of the difficulty of fixing the ends rigidly, it is advis-able always to consider the ends free and to compute the stressesaccordingly. The student is advised not to take the trouble of determining 246 ROOF TRUSSES 33 the wind stresses in trusses of steel truss-ben
Cyclopedia of architecture, carpentry, and building : a general reference work . entrated loads. Since in this case, E^, E^, and the stresses in the knee-braces areless than they are when the columns are free at the base, the windstresses throughout the truss will be less when the columns are fixedthan when they are free. On account of the difficulty of fixing the ends rigidly, it is advis-able always to consider the ends free and to compute the stressesaccordingly. The student is advised not to take the trouble of determining 246 ROOF TRUSSES 33 the wind stresses in trusses of steel truss-bents by the method givenabove, but to use the 40 pounds per square foot of horizontalprojection and to correct the stresses as previously mentioned (seeFig- 39). The formulae of this article giving the stresses in the knee-bracing and the bending moment in the columns, should be used inall cases, and the posts and knee-braces designed according to thestresses so determined. In cases where the 40 pounds per square foot is used, the directstress in each column is: S = 40 X g X Z2. Fig. 48. Notation for FormuUe,Ends Fixed. and the column should be de-signed for this stress, togetherwith the stress due to the bend-ing at the point where the knee-brace joins the column. SeeStrength of Materials, pp. 85and 86. In case a crane is attachedto either the truss or the column,the stresses due to its action mustbe considered in the design. 11. Suspended Loads. Un-der this head come any loadswhich may be suspended fromthe lower chord of the load may not be actuallysuspended from the underneathpart, but may be placed above, and the connections so arranged as to bring the weight on thelower chord. This weight should preferably be concentrated ata panel point. In case it cannot be brought directly to the panelpoint, it may be distributed over a portion or all of the panel. Inthis case the portions distributed to the adjacent panel points arecomputed, and they are, for purposes of comput
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