RAM Connection Gusset Connections FAQ


 Applies To 
 Product(s):RAM Connection
Version(s):All
 Area: Modeling; Design

What design method is used for force transfer of gusset connections?

RAM Connection uses the Uniform Force Method. Other methods, like the KISS method are not implemented in the program.

How can I manually define the gusset plate dimensions?

1.  Edit the connection to open the Connection Pad.

2.  In the Connection Pad, change "Dimensions Calculation" in the General Information box from Automatic to Manual.

3.  In the Connection Pad, scroll to the Interfaces box and select a brace interface (Upper Right Brace, Upper Left Brace, Lower Right Brace, and/or Lower Left Brace). Then, enter the desired dimension for "LV" Length on Column" and "LH: Length on Beam." See screen capture below. If the connection includes all four interfaces, the gusset dimensions need to be manually defined for each interface separately.

Additionally, you can adjust the clearance of the brace to the other members using the Brace - General - Le "minimum distance to other members" and the length of the gusset plate along the brace with the Interfaces - Gusset-to-Brace Connection - Lt and Lh values (for a welded joint). 

4. After defining the manual dimensions, it is likely that the connection geometry will require moment on the connection interfaces for force equilibrium. This will trigger the warning shown below unless a moment is assigned to an interface.

5. In the General Information box, choose set "Moment Provided By" to either Beam or "Column to allow for moment on the beam or column interface. If Beam is selected, moment will be transmitted through the gusset-to-beam interface. If Column is selected, moment will be transmitted through the gusset-to-column interface.

6. When "Moment Provided By" is set to Beam or Column, an additional vertical force can be defined to reduce shear on the gusset-to-beam interface. The additional force is arbitrary and defined in the Members box for the appropriate brace (Upper Right Brace, Upper Left Brace, Lower Right Brace, or Lower Left Brace). If the additional vertical force is set equal to Vb, then the none of the vertical component of the brace force is transmitted to the beam. This matches the discussion for "Special Case 2: Minimizing Shear in the Beam-Column Connection" for the Uniform Force Method Section of the AISC Steel Construction Manual (page 13-3 in the 13th Edition). If the additional force is set to 0, then the shear on the gusset-to-beam interface will not be reduced.

How can I model Special Cases 1, 2, and 3 for the Uniform Force Method that are discussed in the AISC Steel Construction Manual?

Special Case 1: Modified Working Point Location

1.  Edit the connection to open the Connection Pad.

2.  In the Connection Pad, scroll to the Members box and select the brace associated with the modified working point (Upper Right Brace, Upper Left Brace, Lower Right Brace, and/or Lower Left Brace). Then, enter dimensions for Wpx and Wpy to move the working point. If Wpx = Wpy = 0, then the working point is located at the intersection of the column and beam centerlines. Wpx is measured horizontally (left-to-right, positive right). Wpy is measured vertically (up-and-down, positive up). For special case 1, the working point is moved to the corner of the gusset. Wpx would be defined as half of the column depth. Wpy would be defined as half of the beam depth. These dimensions need to be defined manually. There is not a way to automatically force the program to move the working point to the corner of the gusset. If the connection includes all four braces, the working point needs to be modified for each brace.

Special Case 2: Minimizing Shear in the Beam-to-Column Connection

In Special Case 2, a moment is transmitted on the gusset-to-beam interface. Vb on the gusset-to-beam interface is reduced by an arbitrary vertical force to minimize the shear in the beam-to-column connection. If the additional force is set to Vb, then none of the vertical component of the brace force is transmitted to the beam and the vertical force at the gusset-to-column interface will be increased by the additional force defined.

1.  Edit the connection to open the Connection Pad.

2.  Before changing anything in the Connection Pad, click on Results button to launch the Results Report. In the Report Window, scroll to the Interface Force Demands and not Pu for the Beam for the governing load condition. After recording this value, close the Results Report.

2.  In the Connection Pad, change "Moment Provided By" to Beam to allow for moment on the gusset-to-beam



3. In the Connection Pad, find the Members box, select the appropriate brace (Upper Right Brace, Upper Left Brace, Lower Right Brace, or Lower Left Brace) and set "Additional Force" to the force recorded in Step 2. If you do not want to eliminate the vertical force on the gusset-to-beam interface, then a smaller additional force value can be entered. Note that the additional force needs to be calculated manually and is not automatically calculated by the program.

Special Case 3: No Gusset-to-Column Web Connection

This special case can only be modeled in RAM Connection v11.00.00.64 or later. In these versions, enter the Connection Pad and select the Gusset-to-Column Connection for the appropriate brace (Upper Right Brace, Upper Left Brace, Lower Right Brace, or Lower Left Brace) and change "Connection Type to Column" to None. This will detach the gusset from the column.

The vertical dimensions of the gusset can be manually defined using the steps under the frequently asked question, "How can I manually define the gusset plate dimensions?" above for information on modifying the gusset dimensions?" above. Regretfully, the program does not permit a 0" gusset dimension. You will need to add a very small value (say 0.1 in) instead.

Can I design a Gusset Connection using a Pipe Column?

No, currently in Column-Beam-Brace joints (CBB) only Wide flange (W) and Square or Rectangular Tube (HSS-rect) shaped sections can be used for columns. Circular shapes can be used for braces and as columns in some joints, but not the gusset type. A change request for pipe columns in these joints has been logged.

How can I design a Gusset connection with braces in two planes?

Regretfully the design of gusset connections, including gusset base plates, is limited to the design of joints with braces in a single plane. For a corner column connected to braces in two directions you can still design two separate connections, one for each brace or plane, but not a unified bi-axial gusset plate connection.  

Why does the DXF use numbered bubbles?

There is a lot of information to display for a Gusset Drawing so the program creates a separate drawing for each of the significant parts. Use the drop down list to change from the "Main" drawing default to any one of the parts.