Design of Back-to-Back Hot Rolled Channels in RISA

Engineers choose RISA-3D and RISAFloor for the design of all types of steel structures. As a result, we are constantly improving the software and its acceptance of various types of design elements and materials. The latest improvement includes back-to-back hot rolled steel channels which are now available in both RISA-3D Version 20 and RISAFloor Version 16. These member types are becoming more popular in industrial and warehouse structures.

These new shapes are now available for design utilizing the following American and Canadian codes:

• AISC 360-16 (15th Edition)

• AISC 360-10 (14th Edition)

• CSA S16-14

The label of each shape uses the following nomenclature:

2C(depth) x (weight) x (space)

The last value, which represents the space between the channels, is in an eighths of an inch for the AISC database and in millimeters for the Canadian database. For instance an AISC shape 2C15x33.9x6 would be two back to back C15x33.9 shapes with a space of 3/4" (6/8) between them.

The analysis and design of back to back channels are very similar to single channels however the program will take into consideration how the channels are connected to each other. You can specify whether the channels are connected using a bolted or welded connection within the member properties. This will affect how the slenderness ratio is calculated for the member.

Note: When defining a bolted connection, users will also need to define the dimension "a" which denotes the spacing between bolts connecting the channels.

For more information about back-to-back steel channels, please visit the Hot Rolled Steel Database section of the RISA-3D Online Help.