SF Express Headquarter Building – The Skyscraper Center

All-Steel
Both the main vertical/lateral structural elements and the floor spanning systems are constructed
from steel. Note that a building of steel construction with a floor system of concrete planks or
concrete slab on top of steel beams is still considered an “all-steel” structure as the concrete
elements are not acting as the primary structure.

All-Concrete
Both the main vertical/lateral structural elements and the floor spanning systems are constructed
from concrete which has been cast in place and utilizes steel reinforcement bars and/or steel
reinforced concrete which has been precast as individual components and assembled together
on-site.

All-Timber
Both the main vertical/lateral structural elements and the floor spanning systems are constructed
from timber. An all-timber structure may include the use of localized non-timber connections between
timber elements. Note that a building of timber construction with a floor system of concrete planks
or concrete slab on top of timber beams is still considered an “all-timber” structure as the
concrete elements are not acting as the primary structure.

Mixed-Structure
Utilizes distinct systems (e.g. all-steel, all-concrete, all-timber), one on top of the other. For
example, a Steel Over Concrete indicates an all-steel structural system located on top of an
all-concrete structural system, with the opposite true of Concrete Over Steel.

Composite
A combination of materials (e.g. steel, concrete, timber) are used together in the main structural
elements. Examples include buildings which utilize: steel columns with a floor system of reinforced
concrete beams; a steel frame system with a concrete core; concrete-encased steel columns;
concrete-filled steel tubes; etc. Where known, the CTBUH database breaks out the materials used
within a composite building’s primary structural elements.