Hollow structural sections (HSS) produced to ASTM A1085 will consist of additional features to make it a premium product with a higher level of performance.  When compared to ASTM A500, more steel is required to produce the product, because of the tighter material tolerances. Regular testing is also required to satisfy theCharpy V-notch test.  While the additional ASTM A1085 features lead to a price increase of $3/CWT or $60/ton for HSS produced, designing with HSS produced to ASTM A1085 can lead to better utilization of the material and potential cost savings. 

For example, an HSS 8 x 8 x ½, A500, Grade B with an unbraced length of 15 ft has an axial capacity of 441 kips.  An HSS 8 x 8 x ½, A1085 with an unbraced length of 15 ft has an axial capacity of 500 kips.  This is over a 13% increase in capacity with no increase in nominal weight and only a 6-7% increase in cost.

Again, let’s say you had an axial column load demand of 380 kips, an unbraced length of 15 ft and you are constrained to using an 8” square column.  An HSS 8 x 8 x ½, A500, Grade B, KL = 15 ft has an axial capacity of 441 kips and an HSS 8 x 8 x 3/8, A500, Grade B, KL = 15 ft has an axial capacity of 343 kips.  You would select the HSS 8 x 8 x ½ with a nominal weight of 48.85 plf.  An HSS 8 x 8 x 3/8, A1085, KL = 15 ft has an axial capacity of 390 kips which would satisfy the load demand and have a lower nominal weight of 37.69 plf.  This is a weight savings of approximately 23%.

Using ASTM A1085 HSS not only leads to better performance, but also has the potential to save you money.