92 STRESSES IN A TRANSVERSE BENT 



common method is to combine the dead load stresses with the snow 

 or the wind load stresses that will produce maximum stresses in the 

 members. It is, however, the practice of the author to consider that 

 a heavy sleet may be on the roof at the time of a heavy wind, and to 

 design the structure for the maximum stresses caused by dead and snow 

 load ; dead load, minimum snow load and wind load ; or dead load and 

 wind load. It should be noted that the maximum reversals occur when 

 the dead and wind load are acting. For a comparison of the stresses 

 due to the different combinations see Table VI. 



A common method of computing the stresses in a truss of the 

 Fink type for small steel frame mill buildings is to use an equivalent uni- 

 form vertical dead load; the knee braces and the members affected 

 directly by the knee braces being designed according to the judgment 

 of the engineer. This method is satisfactory and expeditious when 

 used by an experienced man, but like other short cuts is dangerous 

 when used by the inexperienced. For a comparison of the stresses in 

 a oo-foot Fink truss by the exact and the approximate method above, 

 see Table VI. 



Stresses in End Framing. The external wind force on an end 

 bent will be one-half what it would be on an intermediate trans- 

 verse bent, and the shear in the columns may be taken as equal to the to- 

 tal external wind force divided by the number of columns in the braced 

 panels. The stresses in the diagonal rods in the end framing, as in Fig. 

 I, will then be equal to the external wind force H, divided by the number 

 of braced panels, multiplied by the secant of the angle the diagonal rod 

 makes with a vertical line (For analysis of Portal Bracing see Chapter 

 XII). 



Bracing in the Upper Chord and Sides. The intensity of 

 the wind pressure is taken the same on the ends as on the sides, 

 and the wind loads are applied at the bracing connection points along the 

 end rafters and the corner columns. The shear transferred by each 

 braced panel is equal to the total shear divided by the number of braced 

 panels. The stresses in the diagonals in each braced panel are com- 



