ASTM A1085

Specification for Cold-Formed Welded Carbon Steel Hollow Structural Sections (HSS)

For nearly all applications, ASTM A500 stands as the preferred choice for Hollow Structural Sections (HSS) up to 88 inches in perimeter. Its longstanding status as the standard reflects its versatility and widespread availability. However, in rare instances where specific needs surpass A500’s capabilities, ASTM A1085 is a viable alternative.

A1085 extends the utility of HSS by accommodating a broader spectrum of applications. A1085 provides additional testing requirements, and improves the efficiency of the HSS members through tighter tolerances and adding property ranges in place of merely having a minimum or maximum value requirement. Locations where this material is used include, but are not limited to, “buildings, bridges, towers, cranes, sign supports and poles, off-shore production and drilling platforms, roll-over protective structures, falling object protective structures, and amusement rides” (ASTM 2015).

It’s crucial to recognize that A1085 isn’t as readily available as A500. Currently, it is produced on demand only, and is not stocked in service centers. Therefore, prior to specifying A1085 for a project, we strongly advise checking the availability of your specified sizes by utilizing STI’s Capability Tool, and then reaching out to the HSS producers listed.

Like A500, the maximum perimeter of round, square and rectangular tubes is 88 inches, and the maximum thickness is 1 inch. However, the minimum thickness tolerance is only -5% of the nominal thickness. Thus, AISC allows section properties to be calculated with the full nominal thickness. This, along with a minimum mass tolerance of -3.5%, increases the efficiency of the HSS tube. For strength, all tubes have a minimum yield strength of 50ksi, with a maximum of 70ksi leading to a lower seismic overstrength factor (R_y) than A500, thus improving the seismic response characteristics. An additional requirement of a Charpy V-notch test of 25 ft-lb at 40° F meets the AASHTO Temperature Zone 2 requirement for use as primary bridge members.

View these ASTM A1085 resources:

• Dimensions and Section Properties ASTM A1085
• ASTM A1085 An Update to a Classic Material Specification, by Kim Olson 

Section properties and design tables are available for A500, A1065 and A1085 in STI Design Guide Volume 1 and 2A and 2B.

For more information on A1085 and other HSS ASTM standards, see our HSS Insider article “Understanding HSS Material Specifications: Which ASTM Should I Specify for HSS?“