ASTM A1085 square and rectangular hollow sections

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

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"

This specification covers cold-formed welded carbon steel hollow structural sections (HSS) for welded or bolted construction that are used in, although not limited to, buildings, bridges, towers, cranes, sign supports and poles, off-shore production and drilling platforms, roll-over protective structures (ROPS), falling object protective structures (FOPS), and amusement rides. This HSS is produced in welded sizes with a periphery of not more than 88 in. [2235 mm] as well as a specified nominal wall thickness of at least 0.148 in. [3.8 mm] and not more than 0.875 in. [22 mm]. The standard addresses areas such as ordering information, the steel-making process, HSS manufacture, heat analysis, product analysis, tensile requirements, flattening test, permissible variations in dimensions, number of tests, retests, test methods, rejection, certification, product marking, packing and loading, and government procurement.

Wall thickness and mass tolerances for A1085 products are essentially the same as those specified for HSS in CSA G40.20-13. Therefore, section properties provided for CSA G40.20 HSS in the Handbook of Steel Construction, which are based on the nominal wall thickness, depth, width or diameter, may be used for design.

The factored axial compressive resistance of an A1085 HSS column may be determined in accordance with S16-14 Clause 13.3.1 with the value of "n" taken as 1.34. The factored axial compressive resistance tables for Class C G40.20 HSS Columns in the Handbook may be used, provided an adjustment for the small difference in Fy values (345 MPa vs. 350 MPa) is taken into account.

Purchasers of A1085 HSS may specify heat treatment, as a Supplemental Requirement S1, which also conforms to the stress-relieved requirement for Class H G40.20 HSS. A value of n = 2.24 may therefore be used for A1085 HSS supplied with Supplemental Requirement S1.

With respect to notch toughness, ASTM A1085 HSS are produced to meet requirements comparable to those of CSA G40.20/21 350WT Category 1. The material is required to conform to a minimum average Charpy V-notch impact value of 34 J at 4°C, as represented by the test specimen. It is noted, however, that the use of notch-tough steel for gravity columns is exceptional.

In addition, a maximum yield stress at 485 MPa as well as a minimum yield stress at 345 MPa apply. Minimum corner radius control is another measure unique to A1085 square and rectangular HSS. All in all, A1085 HSS are superior to A500 products in various aspects.