Stainless Steel

Stainless steel shape properties and design are based on the recommendations in the AISC Design Guide 27 Structural Stainless Steel. The procedure outlined in the design guide follows the 2010 AISC Specification and 14th Edition Steel Manual.

Database Shapes

Shapes are organized by Shape Type and Database / Manufacturer. Common shapes are supported such as wide flanges, tubes, pipes, channels, etc. You can type in the names directly, select shapes from these databases, or add your own shapes.

RISA currently supports only the AISC steel database.

Click on image to enlarge it

Select a Stainless Steel Database Shape

To select a Stainless Steel database shape:

From the Stainless tab on the Section Sets spreadsheet, or the Primary tab of the Members spreadsheet, move the cursor to the Shape field and click .
Specify the database and shape type you wish to use and then select from the list of available shapes.

Shape Designations: Stainless steel shapes are similar to the AISC database for all shapes. See Hot Rolled - Databases for information on the shape designations.

Shape Designations

Stainless steel shapes are similar to the AISC database for all shapes. See Hot Rolled - Databases for information on the shape designations.

Design

Full code checking member optimization can be applied to standard stainless steel shapes based on the AISC Design Guide 27 Structural Stainless Steel which refers to the 2010 AISC Specification and 14th Edition Steel Manual.

How To Apply a Steel Design Code

On the Model Settings - Codes tab, select the steel code from the drop down list.
Click on image to enlarge it
On the Stainless tab of the Members spreadsheet, enter the appropriate bracing information and factors.

Note: For code checking to be performed on a member, the member must be defined with a database shape on the Section Sets or Members spreadsheet.

Design Parameters Spreadsheet

The Stainless Steel Design Parameters spreadsheet records the design parameters for the stainless steel code checks. It can be accessed by selecting Members from the ‘Data Entry’ section of the ‘Explorer’ panel and then selecting the Stainless tab. These parameters are defined for each individual member and can also be assigned graphically. See Modifying Member Design to learn how to do this.

Click on image to enlarge it

The design for stainless steel follows the design for Hot-Rolled Steel Design with a few exceptions outlined below.

Implementation Notes

b/t ratio

The stainless steel b/t ratios differ from Tables B4.1a and B4.1b in Chapter B of the 14th Edition AISC code. The b/t ratios used are listed in the AISC Design Guide 27 Stainless Structural Steel in Tables 3-1 and 3-2.

Axial Compression

The guidelines given in AISC Specification Chapter E apply except with some modifications to the equations and some additional limitations for slender members. See AISC Design Guide 27 for the specific changes.

Bending Capacity

The guidelines given in AISC Specification Chapter F apply except with some modifications to the equations and some additional limitations for slender members. See AISC Design Guide 27 for the specific changes.

Flexure Code Checks

The analysis will be provided for flexure but there will not be any flexure code checks for single angles, tees, sections with slender webs, unequal angles, equal legs angles with slender sections, and round HSS.

Round HSS Shear Buckling

The limit state of shear buckling for round HSS (AISC Specification Equations G6-2a and G6-2b) are beyond the scope of the AISC Design Guide 27 and thus are not included in RISA. The analysis will be provided but there will not be any shear code checks for round HSS.

Combined Torsion

The design of members subject to combined torsion, flexure, shear, and/or axial force is beyond the scope of the AISC Design Guide 27.

Slender WT's and Angle Sections

The Design Guide does not directly address the case of WT's with slender webs or angles with slender webs. Therefore, the program uses modified versions of the similar equations from the AISC specification. This should be considered only an approximation of the capacity of these slender members and should be reviewed and accepted (or rejected) based on the engineering judgment of the user. The equations used are the following:

For slender single angles (or double angles when the legs spacing is nonzero), the equations used in RISA are:

For Wt's with slender stems / webs the equations used in RISA are:

Limitations

The code checks for Stainless in RISA are based on the AISC 360-10 Specification and 14th Ed Manual only.
Stainless code checks only apply to Hot-Rolled Stainless; ASCE 8 is for cold formed stainless and is not considered in RISA.
RISA does not consider the Precipitation Hardening Stainless Steel tension rods which have different safety and resistance factors.
Serviceability checks for deflection based on the secant modulus Es are not implemented at this time. Deflections checks use the modulus of elasticity specified in the Materials spreadsheet.

Stainless Code Check Results

Access the Stainless Steel Code Check spreadsheet by selecting the Results tab Envelope (or LC) button Code Check. Alternatively, on the Results toolbar you can select Code Check.

Click on image to enlarge it

Note:

The Member Detail Report gives more values used to perform the code check.
See Spreadsheet Operations to learn how to use Find, Sort and other options.
See Results View Settings - Members to learn how to plot member results.

Unity Check (UC) Results

The results for stainless steel follows the same results reporting as that for Hot-Rolled Steel Results.