QUESTION 1: Within the CFS industry, there appear to be varying definitions of nominal thickness for coldformed steel gauge. Is there a standard for cold-formed steel thickness and tolerances?
ANSWER: There are various definitions of thicknesses when it comes to cold-formed steel design such as minimum base steel thickness and design thickness, which, along with tolerances, have been defined in the CSA S136-16/AISI S100-16, North American Specification for the Design of Cold-Formed Steel Structural Members. Depending on the CFS sector, there are several standards and fact sheets the user may refer to as well. The CSSBI also published the Steel Facts Sheet 10-12, Sheet Steel Gauges and Thicknesses, which includes and
expands gauge references:
“THERE ARE VARIOUS CFS DESIGN SOFTWARE OPTIONS WHICH CAN BE UTILIZED TO ASSIST WITH THE DESIGN PROCESS AS WELL.”
QUESTION 2: Does the CSSBI produce curtain wall (non-load-bearing) loading tables beyond the published 60 psf design loading for stud limiting heights?
ANSWER: The CSSBI 58-2018 Member Selection Tables are produced in imperial units and metric units. These documents have a specified load range with a minimum of five psf (0.25 kPa) and a maximum of 60 psf (3.00 kPa) in the “Curtain Wall Limiting Height Tables – Single or Double Spans.” All table notes must be considered when utilizing these values. Additionally, these load tables cannot be used with cold-formed steel framing members which are loaded axially (load-bearing). When the loads of a project fall outside of the design table range produced by the CSSBI, the engineer should complete the structural design of the cold-formed steel framing members using the “Stud Section Properties” chart as published in the CSSBI 58-2018 tables and the design standards outlined in the AISI S100-16/CSA S136-16, to determine the members’ resistive properties. There are various CFS design software options which can be utilized to assist with the design process as well. Note that along with the standard resistance (moment, shear, deflection, lateral stability), you must also complete design checks for web crippling and any considerations outside of those listed above as applicable.
