This is one of more powerful options available in Substructure. While defining each of the pier parameters, the program automatically generates a structural model to include all the nodes, members, and connectivity conditions (results shown in the list at the top of the screen). In addition, you can add or remove new checkpoints to the pier structure, as well as define hinges at existing nodes, or choose to do cap design at Face of support or column center lines.

Click the Str. Model button to activate the Structural Model screen. To add additional checkpoints, input a value in the From Left field (under Additional Check Points) and click Add. It will appear in the list under Additional Checkpoints.

The options for plastic hinge locations are enabled only when at least one Seismic Group (in LFD) or one Extreme Event Seismic group (in LRFD) is present. If there are no Seismic Groups included on the Analysis tab, the options for plastic hinge locations are disabled. When Seismic groups are included, program computes plastic hinge moments at two locations in each column, one near the top and the other near the bottom of each column. The default plastic hinge location near top is at the cap column junction (node). The default plastic hinge location near bottom is at the bottom of every column (top of the footing). User can however, specify other locations. For the upper plastic hinge location, the other options allow user to specify the plastic hinge location at the cap soffit or any distance below it. For the lower plastic hinge location, user can specify any location higher than the bottom of the column instead of bottom of column. To specify location other than default, choose the option and specify a distance for it.

You can modify an existing checkpoint by highlighting it in the list, making the appropriate changes, and clicking Modify. To delete a checkpoint, highlight it and click Delete.

Additional checkpoints, once added, can be active or inactive mode. To change the mode of the checkpoint from active to deactive, highlight the checkpoint in the list and click Deactivate.

Hinges can only be added in the Z-direction to any node. For example, if you assign the hinge to node number 3, the moment about Z-direction (Mz) will be zero.

Program offers different options such as at the "centerline of the column, "face of the support " or define "offset distance from c/c of column". If you choose "face of the support" or "offset from c/c of column", program will automatically add check points and do the design for those locations ignoring any locations in cap over column center line.

To view a graphical model of the structure, select Model from the Show menu (Show | Model), or its representative icon on the toolbar. This option allows you to view the node and member numbers and checkpoints.