autocad architecture 2010 structural members

[hbridges]

how do i get bar joist to have extended ends or extended top chords

[dkoch]

You will have to edit the bar joist Structural Member Style. Unfortunately, there is no easy-to-edit single parameter or magic on-screen grip to increase the seat length. You will need a separate style for each different seat condition.

On the Design Rules tab, you will have to modify the offsets of various components to extend the seat, and then adjust the custom display blocks that make up the web members. For example, I took the out-of-the-box Steel Joist 18 style and made a copy (Steel Joist 18 - Seat 12). I increased the seat from the out-of-the-box 8" to 1'-0" by doing the following:

Design Rules Tab
Top Chord: no changes.
Bottom Chord: Changed the X Offset of the Start Shape from 2'-3" to 2'-7"; changed the X Offset of the End Shape from -2'-3" to -2'-7".
JoistSeat-Start: Changed the X Offset of the End Shape from 8" to 1'-0".
JoistSeat-End: Changed the X Offset of the Start Shape from -8" to -1'-0".

Display Properties Tab
Made the following edits to the Elevation, Model and Model High Detail Display Representations (the ones with style overrides set). NOTE: If you make certain that the Automatically Apply to Other Display Representations and Automatically Apply to Object Overrides toggles are checked, you should be able to edit just one of these Display Representations and have the changes made to all three.
Steel Joist End Panel 18 and Steel Joist End Panel 18: Change the Insertion Offset, "x" value from 0" to 4".
Steel Joist Panel 18: Change the Repeat Mode, Repeat Block Display, Start Offset from 2'-10" to 3'-2" and the End Offset from -2'-10" to -3'-2".

The attached ZIP file contains a sample drawing file done in ACA 2010 with the original and modified joist styles as described above.