SNOW LOAD STRESSES 



49 



O' 5' itf 15* 



DEAD AND CE1ILING LOADS 



4 6 



FIG. 31. 



Snow Load Stresses. Large snow storms nearly always occur 

 in still weather, and the maximum snow load will therefore be a uni- 

 formly distributed load. A heavy wind may follow a sleet storm and 

 a snow load equal to the minimum given in Fig. 4 should be considered 

 as acting at the same time as the wind load. The stresses due to snow 

 load are found in the same manner as the dead load stresses. 



Wind Load Stresses. The stresses in trusses due to wind load 

 will depend upon the direction and intensity of the wind, and the con- 

 dition of the end supports. The wind is commonly considered as act- 

 ing horizontally, and the normal component, as determined by one of 

 the formulas in Fig. 6, is taken. 



The ends of the truss may (i) be rigidly fixed to the abutment 

 walls, (2) be equally free to move, or (3) may have one end fixed and 

 the other end on rollers. When both ends of the truss are rigidly 

 fixed to the abutment walls (i) the reactions are parallel to each other 



