Page 50 - Modern Steel Construction (April 2019)

left: A gentle curved steel frame supports an
Omaha hospital entry canopy.

Hot bending. Hot bending is any process
where curvature is induced by load applica-
tion at an elevated temperature. Also known as
heat-assisted bending, the primary advantage of
hot bending is that the material yield strength
is lowered from the room temperature value,
requiring smaller forces to be exerted by the
bending machine. Heat is applied directly to

the member by ame, by heating in a furnace
or by induction coil, followed by the application
of a bending force. The member can be bent
around preset forms, but more often the bend-
ing force is applied using one of the previously
discussed bending methods. For HSS mem-
bers, the heat can be applied either externally or
LEO A DALY
internally. For cambering beams by gag press-
ing, the application of heat is typically used only
where the beam strength exceeds the machine
capacity. To ensure any changes to the member
mechanical properties are insigni cant, tem-

peratures are held below the limits in AISC

Speci cation for Structural Steel Buildings (ANSI/
AISC 360, a free download at www.aisc.org/
speci cations) Section M2.1: 1,100 °F for

ASTM A514/A514M (ASTM, 2016) and
ASTM A852/A852M (ASTM, 2007) steel and
1,200 °F for other steels. These temperatures
are much lower than those induced during
induction bending.

AISC Bender-Roller Committee
Bohlin Cywinski Jackson, courtesy of Arup
Here is a list of current AISC Bender-Roller
above: The Newport Beach Civic Center features curved steel wave roof assemblies that are Committee members:
prominent both inside and outside the building.
A-1 Roll Company
below: Curved steel takes on an industrial aesthetic at Southwest University Park in El Paso Albina Company, Inc.
(home of the El Paso Chihuahuas!). BendTec, Inc.
Chicago Metal Rolled Products
Greiner Industries, Inc.
Hodgson Custom Rolling, Inc.
Holloway Company, Inc.
Hornsby Steel
Kottler Metal Products
Kubes Steel, Inc.
Linders Specialty Company
Max Weiss Company
Midwest Metal Products
Paramount Roll and Forming
Shaped Steel, Inc.
SIMS Steel, Inc.
Trilogy Machinery, Inc.
Whitefab
Visit www.aisc.org/benders for contact
information for all of these companies.
And for more information related to curved
steel, visit www.aisc.org/curvedsteel.
Photo: © Brian Wancho, courtesy of Walter P Moore
50 | APRIL 2019