<<57Se JAi?a€:S ItJ^-V 29 



the joints that the girder has uniform strength; the spacing of the joints depend- 

 ing on the distance between supporting posts and on certain other conditions. 



The foundation, the frame of the first-story wall, supporting columns and 

 girders all being in place, the Hoor joists are next put in. 



Then a temporary floor of loose boards is laid on the joists, so that the 

 workmen can move about freely while raising the trusses into place. 



The plans will show exactly how to cut and put the first truss together — 

 which will look like Illustration 1 , page 26. When this first truss is completed, 

 it may be laid out on the floor, and all the other trusses may then be built 

 exactly like it, one on top of the other, thus insuring absolute accuracy. 



When all the trusses necessary have been finished, the first truss is placed 

 in position at one end of the barn. 



This is usually done by placing the feet of the truss at the places where 

 they are to rest when in position; with the top of the truss toward the center 

 of the barn. Blocks are then spiked to the joists at the proper points, so as 

 to keep the feet of the truss in place while being raised; the feet of the truss 

 resting against these blocks and pivoting on them. 



A gin pole (shown in Illustration 3) is erected at the end of the barn 

 in the center, leaning at an angle of about 45 degrees toward the center of 

 the barn ; a block and tackle is rigged, the rope passing over the gin pole and 

 attached to the upper parts of the truss. A horse or team is hitched to the 

 block and tackle, and the truss quickly raised to position. 



A gang of men can do the same work, but the horse or team is cheaper. 

 A few men with guy ropes are necessary, to steady the truss while being raised. 



As soon as this first truss is up, it is braced in position temporarily, as in 

 Illustration 1 . The second truss is then raised in like manner, and as soon as 

 it is up the girts are added, as shown in Illustration 2. 



Then one after the other the trusses are put in place, the girts being spiked 

 on as you go along. The last two trusses, when laid in position for raising, 

 will project over the end of the barn. The projecting portion is supported by 

 temporary props, which are removed when the truss is being raised. The end 

 girts can be added at any time convenient. 



How much simpler than the old-time barn raising, when heavy timbers 

 were in common use. No longer is there need for getting together thirty to 

 forty men for the raising of a medium-sized barn! Today, a half-dozen men 

 will put up the plank frame in less time than thirty or forty could in the 

 old days. ' 1 



To put on the plates no scaffolding is needed, since it is not difficult to 

 climb up on the truss itself. 



Next the purlines are put in place, raised to position with block and tackle. 



