531 Bracket Connections

Brackets are projections that carry loads. The connection of a bracket to a support has to transmit both shear and moment. Fasteners or welds may be used for the purpose. Connections may be made with fasteners or welds subjected only to shear or to combined shear and tension.

Figure 5.46 shows a plate bracket connected with bolts in single shear. Design of this type of connection is similar to that of the web splice in Fig. 5.42. Each fastener is subjected to a shear load and a load due to moment. The load due to moment on any fastener acts normal to the radius vector from the center of gravity O of the fastener group to the fastener. The maximum load due to moment is given by Eq. (5.13). The resultant of this load and the shear load must be less than the allowable capacity of the fastener. Vectorial addition of the loads due to bending and shear must be performed for the critical fasteners to determine the maximum resultant.

As for a web splice, computations usually are simpler if distances and forces are resolved into horizontal and vertical components, and if J for Eq. (5.13) is obtained from Eq. (5.15).

Exampleâ€”Bolted Bracketâ€”AISC LRFD. Investigate the bracket connection in Fig. 5.46. The A36 steel bracket is to be connected with 7/8-in-diameter A325N bolts to a building column. The bracket carries a 48-kip factored load 15 in from the center of the column web.

The moment arm is 15 in. The moment on the connection is 48 X 15 = 720 in-kips.

tW14 x 43

tW14 x 43

FIGURE 5.46 Bracket with bolts in single shear.

Elastic Method. J is obtained from Eq. (5.15):

By Eq. (5.13), the load on the outermost bolts due to moment is

Renewable Energy 101

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