Building Structures

ARCHITECTURAL CONSIDERATIONS 3
one factor work to degrade others. Some rank ordering of
the various attributes is generally necessary, with dollar cost
usually ending up high on the list.
Integration
Good structural design requires integration of the structure
into the whole physical system of the building. It is necessary
to recognize the potential influences of the structural design
decisions on the general architectural design and on the
development of the systems for power, lighting, thermal
control, ventilation, water supply, waste handling, vertical
transportation, firefighting, and so on. The most popular
structural systems have become so in many cases largely
because of their ability to accommodate the other subsystems
of the building and to facilitate popular architectural forms
and details.
1.2 ARCHITECTURAL CONSIDERATIONS
Primary architectural functions that relate to the structure
are:
Need for shelter and enclosure
Need for spatial definition, subdivision, and separation
Need for unobstructed interior space
In addition to its basic force-resistive purpose, the
structure must serve to generate the forms that relate to these
basic usage functions.
Shelter and Enclosure
Exterior building surfaces usually form a barrier between
the building interior and the exterior environment. This
is generally required for security and privacy and often in
order to protect against various hostile external conditions
(thermal, acoustic, air quality, precipitation, etc.). Figure 1.2
shows many potential requirements of the building skin. The
skin is viewed as a selective filter that must block some things
while permitting the passage of others.
In some instances, elements that serve a structural purpose
must also fulfill some of the filter functions of the building
skin, and properties other than strictly structural ones must
be considered in the choice of the materials and details of the
structure. Basic structural requirements cannot be ignored but
frequently can be relatively minor as final decision criteria.
When need exists for complete enclosure, the structure
must either provide it directly or facilitate the addition of other
elements to provide it. Solid masonry walls, shell domes, and
tents are examples of structures that provide naturally closed
surfaces. It may be necessary to enhance the bare structure
with insulation, waterproofing, and so on, to generate all the
required skin functions, but the enclosure function is inherent
in the structural system.
Frame systems, however, generate open structures that
must be provided with separate skin elements to develop the
enclosure function. In some cases, the skin may interact with
the frame; in other cases it may add little to the basic structural
Figure 1.2 Functions of the building skin as a
selective filter.