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chord and two on the inside of tlxo batter brace, through all of which tlio pin passes. 
Those on the cliord abut against plates rivetted to tlie outside of the baiter brace 
channels ; and those on tlie batter brace abut against plates rivetted to the inside of 
the chord clianncls, all abutting surfaces being planed to fit exactly, so that, when 
the pin is driven ii]fco place, tlie whole joint is as rigid as if it were rivetted, and tlie 
batter brace may bo proportioned as if fixed at the liip. There is also a cover plate 
to protect the liip joint from the weather and to add slightly to the rigidity of the 
connection. This detail is illustrated on PI. IX, Fig, 4, 
The posts are attached to the upper chord pins by extension plates rivetted to 
the ends of tlieir cliamiels, which ends avo planed so as to fit closely up to tlio 
flanges of the chord cliamiels. At tlieir lower ends the bottom chord pins pass 
through holes in tlio webs of the cliamiels, the centres of wliich lioles aro 
located from six to twelve iuclics from the end of the post. Tlie webs arc rein- 
forced by plates on the inside and outside, -wliicli plates are turned up horizontally so 
tha t tliey can bo rivetted to tlie floor beam, in order to resist any tendency that there 
may be to twist tlio post when tlie lateral rods are in action. These details are 
giveii on PI. IX, Figs. 7 and 12 anil on PI. II, Figs. 0 and 10. 
Tlie joints in the bottom chord struts occur near the panel points, but because 
these struts usually act in tension it is well to have as few joints as possible and to 
mako them extra strong. 
Tlie channels can be obtained long enough to span two panels. Tliey will have 
to be slightly bent at tlio middle because of the cambre ; this can be readily done by 
heating them. Tlie connection is made by a reinforcing plate on each side of the 
strut, the plates being several inches deeper than the channels which they splice. 
These plates are used at each panel point even where there is no joint, so as ten 
reinforce the webs of tlie channels at the pin hole. This detail is illustrated on PL 
IX, Fig. 11, and on PI. II, Fig. 10. 
At tlie pedestal the batter brace channels bear evenly against the horizontal shoe 
plate and are attached thereto by means of a bent plate shaped to fit accurately 
inside tlio channels and against the shoe plato. Tlio batter brace upper plate projects 
beyond the channels, and is turned up horizontally so as to boar evenly against tlio 
shoe plate, to wliicli it is rivetted. When channel struts are employed in the bottom 
chords, they connect on the shoe pins, and, if the latter be not supported, produce 
great bending momonts thereon. It is theroforo necessary to proyido an intermediate 
bearing for tlio slioe pin. This cau be done very conveniently by using an I beam 
with the upper flange removed, tlie lower flange being rivetted to tlie connecting plato 
and 01100 plate. This detail is shown on PI. II Fig. 12 and ou PI. IX, Fig. 18. Tlio 
shoe plate at the fixed end of the span, if it be largo enouglx to distribute the pressure, 
rests directly on the masonry which should be smoothly and accurately dressed at 
tlio bearing. If not large enough, it must rest upon a bed plate of wrought iron to 
■vvliich it is to be firmly bolted, tlio bolt heads resting in cavities in the masonry as 
shown on PI. IX, Fig. 14. 
Tlie bed plate, or if there be none, the shoe plate must be firmly anchored to tlio 
maaoury byH>olts either built; into tlie masonry, in wiiicli case there aro washer 
