I would like to analyze a steel roof structure. The rafter components and purlins intersect at the connection points with an offset in height. Is there any modeling option (without introducing an intermediate member) to make the rafter transfer only vertical and shear forces, but no moments? The rafter and purlin members should cross the connection point rigidly; the purlin should not receive any torsion.

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Accepted Answer

In RFEM and RSTAB, you can define a "scissor hinge" for this. Thus, crossings of members are possible without influencing their moment, shear, or axial force distribution.Create a new member hinge and select the Global reference system. Then, activate the scissor hinge options and define the released axes.As shown in the example, you can define the rafters as continuous and rigid. It is then necessary to provide the crossing purlins with the scissor hinge at the common nodes.

Scissor Hinge