This button is only available for hammerhead pier types (for LRFD only). It allows you to add or modify the nodes of a strut-and-tie model. Clicking the Hammer STM button will activate the Strut and Tie Model Edit screen.

To define a strut-and-tie model, start by adding the node coordinates then connect them to create the members within the cap. There are two ways you can define a strut-and-tie model, as follows.

Using the input boxes under Nodes and Members

1. First, to add a node, input the values in the X and Y textboxes under Nodes and click Add. It will appear in the list below. You can modify a node in the list by highlighting it, making the appropriate changes, and clicking Modify. To delete a node, highlight it and click Delete.

   You can add a support to a node by clicking the Set Sup button. If the node is already designated as a support node, this button will be Del Sup; clicking this button will remove the support from the node. For trusses, at least two of the nodes must be designated as Support Nodes.

2. Second, to add a member, select a node from the Start and End lists and click Add. It will appear in the list under Members. You can delete a member by highlighting it and clicking Delete.

Using the mouse to create the nodes and members

• The second method involves using the mouse to create the nodes and members directly in the diagram at the top of the screen. Point the mouse where you want the first node to be in the diagram. Click the left mouse button. A square will appear at this point to indicate a new node. Now, drag the mouse to another location on the diagram. A line appears, extending from the first node. Click the right mouse button. A square appears at this point to indicate another new node has been created and, also, a new member between the two nodes. To stop between creating nodes and members, click the right mouse button.

  To remove all data from the screen, click Reset All. Click OK to accept any changes and return to the Geometry screen.