Increasing The Depth Of Beam. Where beams are required to be of greater depth than can be conveniently obtained by a single beam, two beams are laid edge to edge, and secured in various ways. Fig. 327 illustrates one method known as cogging, caulking or keying. A series of grooves, as a a, fig. 328 - which is a plan of the upper edge of the lower beam b b in fig. 327 - are cut in the edges of the beam, at equal distances, as shown, and keys or cogs c c driven into the grooves. These prevent all lateral or side movements of the two beams a a, b b upon one another; and the beams are secured and kept together vertically by the screw bolts d d. In place of these, straps, as e e, are sometimes employed. These are also sometimes used in place of bolts in scarfing of beams, already illustrated, and also at a a, fig. 329 (A). Other methods of increasing the depth of beams are illustrated in figs. 329, 330, 331. In figs. 329, 330, A is elevation and vertical sections, B plan. Fig. 331 is used in bridge work.

25 Increasing The Depth Of Beam 145

Fig. 327.

25 Increasing The Depth Of Beam 146

Fig, 328.

25 Increasing The Depth Of Beam 14725 Increasing The Depth Of Beam 148

Fig. 329.

25 Increasing The Depth Of Beam 149

Fig. 330.

25 Increasing The Depth Of Beam 150

Fig. 331.