Topic: Joint can extension length
You can control the joint can extension using the JCNOPT card in a input file -
For now, only three options in this card are supported:
What do each of these options?
To avoid misunderstanding the function of this card, here we have a little explanation about, how each of these options works
Option R or N - "Apply Min Can Ext on Lc"
This option allows the user, to consider the can extension since the edge of the connection with the brace towards the start of the can, according to the recommendations for the geometric design of the connection as shown in API Figure 7.2, as a minimum can extension sacs takes the value of "D/4".
For this instance, we'll work with this geometry
Length of members (units ft)
Sections of members
Geometry Model
The minimum can extension for the upper connection is 0.6, which doesn't meet the minimum requirement by the API (D/4), so SACS applies a minimum can extension of 1 ft (12 inches) for both sides of this connection and finalizes using the length of 3.8 ft.
Geometry Used
Sacs Output file
Option L "Apply Min Can extensión if it is not met"
This option allows us to assess the edge length of each connection and determine if the minimum "CAN" extension modeled meets and apply this one, in case this one doesn't meet, SACS apply the minimum recommended by API
Below we present the comparison of the two results considering a minimum length on the right side reel of 2ft (1st model) and a minimum length of 2.5ft (2nd model).
In the upper image the geometry that has an extension of 2 ft doesn't meet the minimum for API, so using the option "L" in the card JCNOPT, allows the software to assess which of these two meet having as a priority the can extension modeled.
Option M "Use the modeled length and ignore the requirement on can ext"
This option allows the user to use the minimum modeled length repeating this on both edges of the connection without considering the minimum requirement by API, this can be most unfavorable for the connection revision. This option is not recommended.