SPECIFICATIONS 



The several members attached to a pin shall be packed 

 so as to produce the least bending moment on the pin, and 

 all vacant spaces must be filled with steel fillers. 



81. Long laterals may be made of rods with clevis or 

 sleeve nut adjustment. Bent loops shall not be used. 



82. Trusses shall preferably be spaced so as to allow 

 the use of single pieces of rolled sections for purlins. Trussed 

 purlins shall be avoided if possible. 



83. Purlins and girts shall preferably be composed of 

 single sections channels, angles or Z-bars placed with web at 

 right angles to the trusses and posts and legs turned down. 



84. Purlins and girts shall be attached to the top chord 

 of trusses and to columns by means of angle clips with two 

 rivets in each leg. 



85. Purlins shall be spaced at distances apart not to 

 exceed the span as given for a safe load of 30 pounds, and girts 

 for a safe load of 25 pounds in Fig. 3. 



86. Timber purlins shall be attached and spaced the same 

 as steel purlins. 



87. Base plates shall never be less than y 2 inch in thick- 

 ness, and shall be of sufficient thickness and size so that the 

 pressure on the masonry shall not exceed 250 pounds per 

 square inch. 



88. Columns shall be anchored to the foundations by 

 means of two anchor bolts not less than i" in diameter upset, 

 placed as wide apart as practicable in the plane of the wind. 

 The anchorage shall be calculated to resist the bending moment 

 at the base of the columns. 



89. Lateral bracing shall be provided in the plane of the 

 top and bottom chords, side and ends ; knee braces in the 

 transverse bents ; and sway bracing wherever necessary. Later- 

 al bracing shall be designed for an initial stress of 5,000 pounds 

 in each member, and provision must be made for putting this 

 initial stress into the members in erecting. 



90. Variations in temperature to the extent of 150 degrees 

 F. shall be provided for. 



405 



Rods. 



Spacing Trusses. 



Purlins and Girts. 



Fastening. 



Spacing. 



Timber Purlins. 



Base Plates. 



Anchors. 



Lateral Bracing. 



Temperature. 



