Info Ges

Shear plane (x)

Shear plane (y) for figure (e)

Shear plane (y) for figure (e)

Fig. 10.18. Multiple shear plane connection procedure.

joint (say the left side) and setting up a series of three-member symmetrical connections such that the central member of each connection is the actual joint member and the outer members are its adjacent members. Where the adjacent members have different properties (i.e. material, cross-sectional or directional) the member on the right side of the connection is replaced by the left-side member to form the symmetrical connection. The value and direction of the design force to be transmitted at the shear plane between the members are then derived by statics, assuming the fastener to be rigid. Knowing the direction of the design force, for each shear plane set-up, the mode failure strength can be determined from the application of the strength equations in Table 10.2 (or 10.3). Commencing with the left-side shear plane, the shear plane strength will be the mode strength having the lowest value and after deleting the incompatible and unacceptable combinations of failure mode in the remaining shear planes, the joint strength can be determined. It must be shown that the strength of each shear plane is equal to or greater than its associated design force. The method produces an approximate and safe result and simplifies what is otherwise a relatively complex problem.

As an example of the application of the method, consider the five-member single bolt joint subjected to design axial forces acting in the directions shown in Figure 10.18a. Members 1,2 and 3 have different properties. From the application of statics, the value of the design force and its direction in each shear plane can be derived as shown in Figures 10.18f-10.18g.

The three-member connections are now formed, working from the left side of the joint. Consider the shear plane between members 1 and 2 (shear plane x) and form a three-member double shear connection by adding member 1 to the other side as shown

 Double shear failure mode Lateral load capacity of shear plane (x) (kN) Lateral load capacity of shear plane (y) (kN) Lateral load capacity of alternative shear plane (y) (kN) Mode (g)
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