AISC –ASD 9th
The requirements of Supplement No. 1 (December 17, 2001) are included as an option in the ASD joint design. Select ASD Supplement No.1 to implement the following revision:
"Pbf = the computed force delivered to the flange or moment connection plate multiplied by 5/3"
This removes the distinction between lateral load cases and gravity load cases on the value of Pbf.
Panel Zone Check
For calculation of strength purposes the depth of the web plate (when one is required) is assumed to be the clear distance between column flanges. This is true for both rolled and built-up sections. For a rolled section the full depth of the section is considered when calculating the web panel zone capacity, for built up sections only the clear distance between the column flanges is used to calculate the web capacity.
When panel zone check is performed for sloping columns, the depth of the web plate (when one is required) is assumed to be the horizontal clear distance between column flanges.
Local Web Yielding
According to AISC the column capacity to prevent local web yielding is diminished at the ends of a member. In RAM Frame this provision applies to the top of the column, when no column exists above. To calculate the column capacity at these locations RAM Frame uses the maximum of the framing beams flange thickness or the columns k dimension (distance from outside face of column flange to the web toe of the web-to-flange fillet) in equations K1-2, K1-3. If a web plate is present then the plate thickness and yield strength are used in these equations, along with the column properties (flange thickness etc).
Web Crippling
The same restrictions are applied in calculating the Web Crippling Capacity according to chapter K1.4 as are taken when calculating the Local Web Yielding capacity. That is, when calculating the column capacity at these locations RAM Frame uses the maximum of the framing beams flange thickness or the column’s k dimension (distance from outside face of column flange to the web toe of the web-to-flange fillet) in equations K1-4, K1-5. If a web plate is present then the plate’s thickness and yield strength are used in these equations along with the column properties (flange thickness etc).
Stiffener Design
Stiffeners are designed in accordance with Specification K1.8. The force used to design stiffeners is considered to be the difference between the applied load and the capacity of the column to resist this load. For some of the above joint checks the forces are converted from working stress to capacity values. Where these forces resulted in the use of stiffeners they are converted back to working stress forces for stiffener design. Refer to AISC K1.2 for conversion from working stress to capacity values.