328 BUILDING DETAILS 



A f -in. bolt will ordinarily test in a tensile pull to from 

 15,000 to 17,000 Ib. Thus, it can be considered to sustain 

 safely a load of about 4,000 Ib. 



Where it is necessary to bolt heavy machinery to the 

 ceiling, the location should be ascertained, and heavy 

 through bolts should then be embedded in the concrete work 



BEAM SOCKETS 



Styles of Sockets. The socket shown in Fig. 5 (a) is known 

 as the Unit socket. The cast-iron part a rests on the bottom 

 of the form load, and is bolted to it by the bolt fc, which 

 passes through a hole in the bottom of the forms. This 

 socket, as shown, clamps to four reinforcing rods of the beam 

 or girder in which it is placed. In (b) is shown a malleable- 

 iron socket. It is tapped at a to receive a stud bolt. This 

 socket is secured to the form boards by means of lugs b, 

 through which nails are driven into the wood. 



The socket shown in (c) is known as the Jennings -Stein- 

 metz socket. It consists of a piece of pipe swaged out or 

 broken at the upper end, as indicated at a, with a solid 

 wrought-iron bar or block welded to the other end. The 

 solid portion of the block is tapped out for the bolt b, which 

 passes through the bottom board c of the form. 



What is known as the Hancock insert is shown in (</). 

 This device consists of a cast- or malleable-iron casing that 

 is made in loose halves a, and is wired together through the 

 lugs b cast on the side. Before the two halves of the insert 

 are wired together, however, there is placed in the recess 

 a nut c, into which a bolt can be screwed from beneath. 

 The castings are arranged with lugs, or flanges, d on the face 

 end and by means of these the insert may be screwed or 

 nailed to the form board and thus secured in an upright and 

 secure position when the concrete is placed. The flange e 

 at the top of the insert furnishes additional bond, or key, 

 with the concrete. The Hancock insert is made in 3-, 4-, 

 and 6-in. lengths for \-, f-, ,- and 1-in. bolts. 



In (e) is shown the Bigelow socket. This casting, which 

 is made of malleable iron, is arranged with a slot a that is 



