214 FRAMEWORK 



tain tables that give weights, areas of sections, positions of centers of 

 gravity, moments of inertia, radii of gyration, etc., for the shapes 

 manufactured by the different companies. Tables are also given for 

 the resisting moments on pins, the shearing and bearing values of rivets, 

 standard bolts, eye-bars, bridge pins, standard connection angles, bear- 

 ing plates, minimum size of rivets, spacing of rivets, and many other 

 useful tables. The handbooks best known are as follows, the popular 

 name being given in brackets : Cambria Steel (Cambria), issued by the 

 Cambria Steel Company, Johnstown, Pa. ; Pocket Companion (Car- 

 negie), issued by the Carnegie Steel Company, Pittsburg, Pa.; Stand- 

 ard Steel Construction (Jones & Laughlins), issued by Jones & Laugh- 

 1ms, Limited, Pittsburg, Pa.; Steel in Construction (Pencoyd), issued 

 by A. and P. Roberts Company, Philadelphia ; and Structural Steel and 

 Iron (Passaic), issued by the Passaic Rolling Mill Company, Pater- 

 son, N. J. These books can be obtained for from 50 cts. to $2.00. The 

 American Bridge Company issued, in 1901, a book entitled Standards for 

 Structural Details, for use at its various plants. 



The Carnegie handbook was formerly very generally used in de- 

 signing offices, but recently the supply has been limited so that the Cam- 

 bria handbook has taken its place in schools and in many offices, and 

 for this reason references will be made to Cambria in obtaining weights, 

 properties of sections, etc. All references to Cambria will be to the 

 1903 edition. 



Design of Trusses. The method of determining the proper sizes 

 of the truss members will be illustrated by designing a few of the 

 members of the truss in the transverse bent of the mill building shown 

 in Fig. 53 ; the stresses in which are given in Table VI. The secondary 

 members will be omitted from the truss in the design, as they were in 

 obtaining the stresses. 



The material will be assumed to be medium steel and the allow- 

 able stresses as given in Appendix I, will be taken. The allowable 

 stresses are as follows: 



Tension 16,000 Ibs. per sq. in. 



Compression 16,000 70 / -=- r Ibs. per sq. in. 



