Modeling and Designing Gusset Connection in Staad.Pro
Consider the goal post frame shown below comprising open formed columns and open formed beam section at the top and a diagonal angle brace:
All sections have been inserted with a beta angle of 0 degrees. For the angle this means that the orientation is, showing the column and brace only for the top left hand joint:
If the beta angle for the angle section was changed to 90 degrees the angle would be orientated as shown below:
If the beta angle for the angle section was changed to 180 degrees the angle would be orientated as shown below:
If the beta angle for the angle section was changed to 270 degrees the angle would be orientated as shown below:
The angles must be inserted with a beta angle of either 0, 90, 180 or 270 degrees in order for the connection to design in the RAM Connection module. If the beta angle is changed to something other than these values to orientate the angle in the 3D view then the connection will NOT design in RAM Connection. This is due to the default values used by RAM Connection for the orientation an angle, in a Gusset plate design, being 0, 90, 180 and 270 degrees.
If we analyze the model above with pinned base supports and a point load of 20KN applied at node 2 along with a uniformly distributed load applied to the top beam of 10KN/m, as shown on the figure below:
Following this we can then select the RAM Connection module. In here we can select the members forming the gusset plate connection as shown below:
We can then select the Gusset plate icon to select the options for designing this type of connection. In this example, I have selected the AISC 360-05 (ASD) design code and the CBB_DA connection type (Column, Beam, Brace, DA signifies that the connection is a bolted connection):
If we then select OK we obtain, note the comment about the angle being considered as a brace, that is to say capable of accomodating axial load only, regardless of the fixity at the ends:
If we Close this dialog box we have the following and the connection can be selected using the Select Joints cursor or by double clicking on the RAM Connection Input selection:
This opens up the Connection Pad dialog box where the connection can be reviewed and edited if required. Note in the connection graphic the orientation of the angle has been changed to accommodate a connection to the gusset plate.
If we now go back to the Modeling tab and change the beta angle to 45 degrees say to orientate the angle as shown below:
And, if we now reanalyze the model and again go to the RAM Connection to select the members to design the connection:
This time we obtain:
In Summary:
- For single angles, only beta angles of 0, 90, 180 and 270 are acceptable for connection design in the RAM Connection module.
- Gusset plate design is only applicable for design code AISC 360
- If a brace is assigned in Modeling as a fixed ended member it will be considered as axial loaded only in RAM Connection. Braces must be defined with the Truss command in Modeling if the connection is to be designed in RAM Connection module.