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to acfc as fulcra for tlio levers by which the chord sections are lifted aud 
e W in place while being connected. 
The cap of the upper falsework should be deeper than it is broad, because it 
0 act as a beam, and may be subjected to considerable shock, when the chord 
sections are being put in placo. The method of bracing sliowa on Plate XI. is spe- 
y advantageous in respect to this consideration. 
Tlie upper falsework should be braced longitudinally as well as transversely. 
The sizes of tlie posts will vary from G 〃 x 6" to 8" x 8" according to tlieir 
n o 1 and the weight which they have to support. 
. I n both the upper and lower falsework the diagonal bracing in planes parallel 
e longitudinal axis of the bridge should for economy’s sake be placed between 
^ lUa ^e pairs of bents ; that is， every other space between bents will be braced : 
e end spaces should, however, be braced in any case. 
^ Plate XI. gives an illustration of liow the working drawings for falsework should 
made. For economy of space the scale lias been taken at one quarter of an inch 
16 foot ; bufc it should, if intended for an actual case of framing, be twice as 
S r eat. a. drawing of this kind should be accompanied by bills of lumber and iron 
in a similar manner to that explained in Chapter XVII. Measurements 
jj ls ^ auces between bolt holes should be both scaled and calculated : those on 
a e XI. were simply scaled, as the plate is intended for illustration only, 
j P le foreman of the work should be furnished with a blue print of the working 
£=^ 叫 8 f Qr the bridge, unless the type of structure be one with wliicli lie is per- 
M y laimliar. He must also be provided with a raising bill, which should consist 
a skeleton diagram of one truss with the following information written thereon. 
Size of each truss stmt and tie and raark for same ; also number of pieces of 
ame ln a Panel of one truss. 
^iaruefcors aud lengths s. to s. of pins with tlieir marks. 
Diameters, lengths and marks of fillers for same. 
• lz 6s and marks of all separate plates belonging to tlie trusses, each in its pro- 
^ ^ a gram for the lower lateral system giving the following information ; 
Sizes and marks of rods 
Positions of same showing which eyes are to go next the trusses. 
Sections, lengths and marks of lateral struts. 
Diameters and lengths of lateral pins, if any. 
, Diameters and lengths of fillers for same. 
• lagvara for the upper lateral system and portal bracing giving the following 
Sizes and marks of rods. 
Positions of same showing which eyes are to go next the trusses. 
Sections and marks of lateral and portal struts, 
diameter and length of mortal pins. 
Diameters and length of fillers for same. 
Diameter and length under head of portal strut attaching bolts. 
