:><; \OTES ON PLAT&GIRDEB DESIGN 



The >t ringer i- composed of 1 wel> plate 27 Xj; 



4 angles 5X3JX13.6 (i"). 

 Tin- flnorlieam i- compose. 1 f 1 \\.-h plate 38 X i ; 



4an.L'l- :. <3iXl9.8 (}") 



The iiiaxiinuin stringer react ion is <)7.S(H) Ibs. (// 48,800 

 I in p. =46,600 and dl- 2400). 



The maximum reaction for t\v<> stringers is 131,700 Ibs. 

 (#-60,300, Imp. =60,600 and $ = 4800). 



The requirements of construction will be assumed to 

 demand that the bottom flange of the stringer be 4J" 

 above the bottom flange of the Hoorbeam. The connection 

 between the stringer and floorbeam is made by two ver- 

 tical angles which are riveted onto the stringer in tin- 

 bridge shop. The rivets through the outstanding legs of 

 the connection angles and the floorbeam web must be 

 field driven. The unit stresses are 12,000 and 24,000 for 

 shear and bearing for shop riveis and 20% less than these 

 values for field-driven rivets; J" rivets will be used and 

 the connection angles will be made J" thick so that after 

 they arc faced on the back of their outstanding legs tiny 

 will not be less than j" thick on these legs. 



Fig. 11 (d) shows how the load W is applied to each 

 rivet and carried to the stiffeners. The rivet should be 

 examined for crushing by the web for W and for shear 



W 

 for T . 



97 800 

 The number required for < i u>liir>g = in y - nn =9.3 or 10. 



1U,OUU 



( 7 SIM) 



For shear the number = '-o"*^ or ^* ^ ne u PP er 



and lower rivet in the lines xx and zz of (b) cannot be 



