— 175 — 
The area of the shoo plate is 25" x 30" less about 80 square inches for the 
bolt holes, or 720 square inches which multiplied by 200 and divided by 
’ gives 72 tons as the greatest permissible pressure upon the shoe plate, if it 
r ° 8 S C ^ rß ctly on the masonry. 
虹 e 8 rea tesfc actual pressure was ascertained to be 78 tons, therefore we must 
er Us e bed plates at the fixed end of the span or increase the area of oach shoe 
七。 マ ⑹ + ⑽ = 810 square inches. If we make tlie width 26^ and the length 
, we will have 882 square inches of area, and there will be no undue projection 
p = beyond the pedestal, therefore this method will be adopted, 
plate ふ ^ or track stringers may be made J 7 x 14 7 x 14", and tlie anchor 
0 £ , beam hanger plates may be made 14" thick. The distance between centres 
Ch G ? m l) an g er8 may he averaged at 9." A 1A" square bar upsets (vide table in 
1 , , . 1 ん） to for which the greatest diameter of a hexagonal nut is (vide 
Sv 6 W Sarüe chapter) 4,04”, making the necessary length of plate 13". Tlie neces- 
Y width will be 4 ;, ^ - 1Ä" + 4 〃 say 1)ゲ ’. The weight [of each of tlie two name 
e^inay be ftssumed to bo 50 pounds. 
1 - X eX ^ come the latticing and lacing bars. Tlie spread oftlioso foi. the top chords 
. a ^ or braces is about 17", aud tlie stretch should be about the same. The 
^i'ac 1 ^ s P ace latticed on each chord panel is about 18 f 6 7 f and that on each batter 
26 ba: ，明 ’ 6 '， w hich distances divided by ll ,r and multiplied by 2, show that 
1Yln レ rs be required for each panel length of chord and 40 for each batter brace, 
ma kmg the total number 472. 
ip._ a ^ e XX. makes the size of the bars 普" x 2i ,f 9 and Table XIX. makes tlie 
i\ * 008 . + 0,281 = 2i， nearf y, 
a ud 1 U * a 8 ^ m ^ av ma nner are determined tlie number and climoiibions of all the lattice 
、vill aCm g bars recorded iu the u Bill of Iron For simplicity in shop work we 
the i) Se May 1〕1心 8 instead of lacing for tlie lower lateral struts : these will permit of 
age of the stringer connecting plates through the struts. 
atl( j a eil ?^s of the pins on the ft Bill of Iron n include an allowance for tlie liufcs, 
iu Cli lC f ( Uc ^ on ^ or diminished diameters. The diameter of tho anchor bolts is found 
\V ミ ei H to be lj /f , and their length may be assumed to be 6 , . 
lasted a ll ow 100* for temporary bolts used in erection : these need not be 
Au all， 
Let 1 
fo て they can bo saved for erecting another bridge. 
owanoe of 150* for ornamental work will be sufficient. 
foot of ^j? S a ' era 8 e the length of filler for each piu at 4", ami the weight per lineal 
P°unds el% 以 12 pounds or the weight of each filler or pair of fillers on a pin 8 
the middle 16 仙⑽ over en< l floor beams, we will employ 12^ 一 42* I divided along 
p o (二 0 f 山〇 web, as there is no tee iron deep enough in Carnegie’s sections. 
u pper 乃 16 S ^ AOe supporting pieces, we will employ 12” 一 60 1 * I beam with tlie 
the ü °. e lem °ved: tlie length may be averaged as in the Bill of Iron to obtain 
1 0X1 _ け eight. 
Weight of tlie stringer bracing frames is included in that of tlie stringers. 
