bers, the diameter of the rivet-holes will be assumed as 

 -J inch larger than the undriven rivets. 



64. The rupture of a riveted tension member is to be con- 

 sidered as equally probable, either through a transverse line 

 of rivet-holes or through a zig-zag line of rivet-holes, 

 where the net section does not exceed by 30 per cent, the 

 net section along the transverse line. 



The number of rivet-holes to be deducted for net section 

 will be determined by this condition. 



Bolts. 65. When members are connected by bolts the holes must 

 be reamed parallel and the bolts turned to a driving fit. 

 All bolts must be of neat lengths, and shall have a washer 

 under the heads and nuts where in contact with wood. 

 Bolts must not be used in place of rivets, except by special 

 permission. 



66. All nuts must be of hexagonal shape. (93.) 

 Splices. 67. All joints in riveted tension members must be fully 

 and symmetrically spliced. 



68. Riveted tension members shall have an effective sec- 

 tion through the pin-holes one-third in excess of the net 

 section of the member, and back of the pin at least 60 per 

 cent, of the net section through the pin-hole ( 41). 

 Abutting joints. 69. In continuous compression members, as chords and 

 trestle posts, the abutting joints with planed faces must be 

 placed as close to the panel points as is practicable, and the 

 joints must be spliced on all sides with at least two rows of 

 closely pitched rivets on each side of the joint. 



Joints in long posts must be fully spliced. 



70. In compression members, abutting joints with un- 

 tooled faces must be fully spliced, as no reliance will be 

 placed on such abutting joints. The abutting ends must, 

 however, be dressed straight and true, so there will be no 

 open joints. 



web splices, /i. The webs of plate girders must be spliced at all joints 

 by a plate on each side of the web. 



72. All web-plates must have stiffeners over bearing 

 points and at points of local concentrated loadings ; such 

 stiffeners must be fitted at their ends to the flange angles, 

 at the bearing points. ( 47, 48.) 



