22 STANDARD SPECIFICATIONS 



of details and anchor-bolts capable of resisting one and one- 

 half (1J) times, the specified lateral (Pars. 62, 63) and longitu- 

 dinal forces. (Pars. 64, 104.) 



85. Wooden Trestles. (See Pars. 285, 286, 287.) 



86. All Structures. Structures shall be so designed that all 

 parts will be accessible for inspection, cleaning, and painting. 



Pockets or depressions which would hold water shall have 

 drain holes, or be filled with waterproof material. 



DETAILS OF DESIGN 



87. Minimum Size of Material. No rolled shape, except 

 channels, or metal of less thickness than ^ in., shall be used 

 except for fillers. The webs of channels shall not be less than 

 i in. No angles shall be less than 2J"X2J"Xft", and no rivets, 

 except in beam connections, lattice and railings, shall be less 

 than | in. in diam. (Pars. 95, 101.) 



88. Details of Joints. Main members of trusses shall be so- 

 arranged around the joints that their neutral axes will meet 

 in a common point. 



The sections of top chords and inclined end posts generally 

 consist of two rolled or built-up channels and a cover plate; such 

 unsymmetrical sections must be so proportioned as to bring the 

 neutral axis near the center of the webs. (Par. 90.) 



Abutting joints in compression members when faced for 

 bearing shall be spliced on four sides sufficiently to hold the con- 

 necting members accurately in place. 



All other joints in riveted work, whether in tension or in 

 compression, shall be fully spliced. 



89. Details of Connections. The strength of connections 

 shall be such as to cause the main member to fail should the 

 combination be tested to destruction. (Par. 90.) 



No connection except for lattice bars or lattice angles shall 

 have less than three rivets. 



All joists and stringers shall preferably be attached to the 

 floor beams by means of connecting angles and shall, wherever 

 possible, rest upon shelf angles stiffened by vertical angles if 

 necessary. The rivets, however, in such shelves shall not be 

 assumed to carry any part of the shear. 



The calculated number of rivets connecting the stringers 



