Building Structures

ARCHITECTURAL CONSIDERATIONS 9
Figure 1.12 Accommodation of air ducts in the floor–ceiling
construction: (a) by running major ducts parallel to major beams;
(b) by varying beam depth; (c) by penetrating exceptionally deep
beams.
Because of the stacking required, vertical structural elements
are often a constant plan condition for each level, despite
possible changes in architectural requirements at the various
levels. An apartment building with parking in basement levels
presents the problem of developing plans containing fixed
locations of vertical structural elements that accommodate
both the multiple parking spaces and the rooms of the
apartments.
Vertical structural elements are usually walls or columns
situated in one of three possible ways, as shown in Figure 1.13:
1. As isolated and freestanding columns or wall units in
the interior of the building
2. As columns or walls at the location of permanent
features such as stairs, elevators, toilets, or duct shafts
3. As columns or walls at the building periphery
Freestanding interior columns tend to be annoying for
planning, because they restrict placement of doors and walls
and are usually not desired within rooms. They are clumsy
to incorporate into thin walls, as shown in Figure 1.14. This
annoyance has motivated some designers to plan buildings
with very few, if any, freestanding interior columns. The
middle plan in Figure 1.13 shows such a solution, with interior
supports only at the location of permanent construction. For
Figure 1.13 Development of vertical supports in multistory
buildings.
buildings with fixed plan modules, such as hotels, dormitories,
and jails, a plan with fixed interior bearing walls may be
possible, as shown in the lower figure in Figure 1.13.
When columns are placed at the building periphery, their
relationship to the building skin has a great bearing on the
exterior appearance as well as interior planning. Figure 1.15
shows various locations for columns relative to the building
skin wall.
Although freestanding columns (Figure 1.15a) are usually
the least desirable, they may be tolerated if they are small (as in
a low-rise building) and are of an unobtrusive shape (round,
octagonal, etc.). The cantilevered edge of the horizontal
structure is difficult to achieve with wood or steel framing but
may actually be an advantage with some concrete systems.
Placing columns totally outside the wall (Figure 1.15e)
eliminates both the interior planning intrusion and the