Tubular Truss – Gapped K-Connection with square HSS and unbalanced branch loads

Steel Design Guide 24 - Example 8.5

References

Packer, Jeffery A., Donald Sherman, and Maura Lecce. Design Guide 24: Hollow Structural Section Connections. Chicago, IL: American Institute of Steel Construction, 2010.

Details

From the reference:

A planar roof truss contains the planar HSS 45° gapped K-connection shown in Figure 8-10. Note that the chord moment is necessary for equilibrium because of the noding eccentricity. Because the vertical components of the branch member forces differ by more than 20%, the connection must be treated as a combination of two types: a K-connection and a cross-connection [see AISC Specification Section K2(b)], as will be demonstrated. The loads shown consist of live load and dead load in the ratio 3:1. Determine the adequacy of the HSS connection and also consider the design of the welds.

Refer to the figure in the reference for additional details.

Results

Table 1.
Parameter RAM Connection Reference Difference
K Gapped connection – Branch chord wall plastification capacity (kips) 414.94 415 None
X connection – Branch chord wall plastification capacity (kips) 276.36 277 None