Page 44 - Modern Steel Construction (April 2019)

twist along the member axis. Special tooling is often required to Compound bends. A compound curve has two or more arcs in
limit distortion and ensure dimensional accuracy. Off-axis bends the same plane, joined tangentially without reversal of curvature.
are used when members are both curved and sloped, and a mem- The members can be fabricated as a continuous curve or with a
ber axis must be parallel to the curved surface. In commercial straight segment between tangent points. Compound bends can
structures, this can occur in canopies, arched roofs and horizontal be formed from a single straight member or by bending two or
members in a dome. These members are also used for circumfer- more straight members into simple curves and splicing them
ential stiffeners in industrial cone-shaped plate structures, such as together. Members with compound bends are used to support
hoppers and stacks. both vertically and horizontally curved architectural features. In
industrial structures, they are typically used for monorail beams.
Reverse-compound bends. A reverse-compound curve,
Curved steel offers an endless array of spiral stair possibilities. also known as an S-curve, has two or more arcs in the same
plane joined tangentially with reversal of curvature. Completed
I-shaped and HSS members with reverse-compound bends are
used in the same applications as compound bends.

Anvil Craft Corp. A curved stair stringer with markings for the treads and risers.
44 | APRIL 2019