42 BULLETIX 1259, U. S. DEPAETMEXT OF AGEICULTURE. 
of the girder above the roadway. The first flange plate 
or a plate of the same \sddth will be bent around the 
curve and continued to the bottom of the girder. In a 
bridge consisting of two or more spans only the comers 
on the extreme ends need be rounded, unless the spans 
have girders of varying heights, in which case the higher 
girders shall have their top flanges neatly curved down 
at the ends to meet the top comers of the girders in the 
adjacent spans. 
int' "^^^ ^^^^' -^•'^^ bearings of girders on masonry shall be raised 
above the bridge seat by metal pedestals or plates a 
height of at least 2 inches. 
75. Sole and Solc and masonry plates shall each be not less than 
masonry plates. ^ ii^ch thick. 
76. Camber. Li general, camber vnR not be required in plate girders 
except for long spans or special conditions. When used, 
it shall be sufficient in amount to meet the requirements 
of the engineer. 
TRUSSES. 
77^ Main fea- Preference will be given to trusses vriih single inter- 
secting web members or other forms of trusses possessing 
the least ambiguity in computed stresses and the greatest 
elements of serviceability. Adjustable members in any 
part of the structure preferably shall be avoided. Mem- 
bers shall be symmetrical about the central planes of 
trusses and all parts shall be so designed that they can 
be inspected, cleaned and painted. 
Through riveted and pin-connected spans will generally 
have inclined end posts. Low truss spans shall be of. 
the riveted type. In low truss spans, laterally unsup- 
ported hip joints or ''flpng hips" shall be avoided. 
78. Top chords Top chords and end posts of low and through truss 
and end posts, gp^j^g g}^^^ ]3^ made usually of two side segments \\'ith 
one cover plate and with tie-plates and lacing on the 
open side. In chords of light section, tie-plates and 
lacing may be used in place of a cover plate. 
Top chords of deck trusses subjected to direct loading 
shall be designed for the cross bending occasioned by 
the dead, live and impact loads of the floor system, in 
addition to the direct chord stresses, and all top-chord 
splices shall be proportioned for those stresses and any 
shearing stresses they may receive. 
Where the shape of the truss permits, compression 
chords shall be built continuous, with splices located as 
near the panel points as possible and preferably on the 
side subjected to the smaller stress. 
The top-chord sections of low truss spans shall be so 
proportioned that the radius of g}Tation about the ver- 
tical axis of the member shall be at least one and one-half 
times the radius of gyration about the horizontal axis. 
79. B 1 1 o m The bottom chords of riveted trusses generally shall 
chords. ^^ spliced near panel points and on the side farthest 
away from the center of the span. 
