|
Feature:
New Manufacturing Methods, New Standard
Contributed by Karen Thornton, AISC
When changes in steel manufacture of structural shapes made an
old standard obsolete, the American Iron and Steel Institute came
together with stakeholders in ASTM Committee A01 on Steel, Stainless
Steel, and Related Alloys to meet the new needs of this crucial
industry.
This past year, ASTM developed and promulgated a new specification,
A 992, Specification for Steel for Structural Shapes For Use in
Building Framing, that more accurately reflects current production
practices and also addresses the needs of engineers and welders.
ASTM Committee A01 on Steel, Stainless Steel, and Related Alloys
developed the standard at the request and with substantial input
from the American Institute of Steel Construction.
ASTM has always provided the material standards used by AISC,
structural steel fabricators, welders, and producers, and has
been an active participant in A01 and F16 for many years. The
relationship between AISC and ASTM has always been a strong one.
The ASTM consensus is stronger than just history, however. ASTMs
position as a standard-setting organization offers enough influence
to give companies in the steel industry the stability necessary
to invest resources necessary to furnish material in compliance
with the new standard. ASTM provides a forum in which expertise
from producers, designers, and fabricators meet to balance needs
and production practices. Knowledgeable representatives from the
steel industry who make and use the product give their advice
and opinions on whatever standard is being tested, therefore providing
protection from many different areas of harm in the industry.
With the knowledge that the standard has been scrutinized in the
ASTM consensus process, the AISC Specification Committee, the
American Welding Society Structural Welding Committee, and model
building codes have been able to include the standard in building
construction documents.
The new standard has great benefits to the specifier. A 992 has
a maximum yield point and a specified yield tensile ratio. It
also limits the maximum carbon equivalent for weldability. The
yield tensile ratio does two things: helps control fracture in
connections and assists in achieving plastic moment capacity.
Because of A 992s great marketability, the designer now has control
over energy dissipation in seismic design as compared to A 36,
Specification for Carbon Structural Steel, providing a more tightly
defined material for seismic design.
A 992 will hopefully become the material of choice in structural
wide flange shapes for engineers and welders. The fabrication
industry looks to the day when inventory is reduced because they
will no longer need to keep and control multiple grades of steel.
A 992 moves the structural steel industry towards the use of simple
high strength grade in building design. And because of ASTMs
influence, the steel industry will know that A 992 is a safe and
quality standard.
|