JOINTS AND CONNECTIONS 



161 



Y 



D X 1 



2.02 in., so the end bolts may be placed 2.02 + -^- 



= 2.395 ins. from the end of the plank. 



In Fig. 95 is shown (with width exaggerated) the arrangement 

 of the bolts. The spacing so carefully figured is the closest safe 

 spacing. The bolts can be placed much farther apart if desired. 

 In the middle splice carrying all the tension place two bolts seven 

 inches from the ends of the planks. Space the remaining bolts 

 10 ins. center to center. The 14-ft. lap in the middle of the truss 

 is then connected up so that the two outer planks act to carry 



y. _ _JLt' 



_. . J 



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^ Lap H'O'^ 



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- .*-. T .-f-.. TT , 



2#"--U- 2*">*< 2*"->J<--2#"4^2# : 





Fig. 95 



hah* the tension from one support to the other. It now remains 

 to bolt the other two outside planks to them in order that the rest 

 of the tension can be carried. 



There should be two bolts close to each joint, so, six inches from 

 the end of the planks, put in two bolts. Each joint has 16 bolts in 

 two lines, which bolts may be spaced 12 ins. center to center. For 

 the rest of the chord put bolts at intervals of 4 ft. staggered and 

 at the very end put two bolts through 6 ins. from the end to make 

 a firm bearing for the end of the brace. Between the bolts, 

 used merely to hold the planks firm, large spikes may be driven 

 at intervals of about 12 ins. to make the whole construction 

 more rigid. 



The same principles apply when five or more planks are used. 

 In such a case, however, it often happens that long planks may 

 be placed in the middle of the span in such manner that all the 



