vertical slots. This detail simultaneously allows horizontal load transfer
and unrestrained vertical movement between the plates and the roof
structure.
Structural actions
Detailing that expresses structural actions within members and con-
nections also provides opportunities for architectural enrichment.
According to Collins, Soufflot, the eighteenth-century Rationalist archi-
tect who reacted against the ornamental embellishment of structural
details, advocated ‘simply limiting aesthetic effects to those which logic-
ally followed from the nature of the structural component, and design-
ing those components in accordance with rational criteria’.^6 But the
pendulum has swung since the 1700s. Now, architects such as Louis
Kahn react against bland concrete and timber members muted by their
rectilinearity in both cross-section and longitudinal elevation, and ‘off-
the-shelf’ steel sections that satisfy nothing other than the outcome of
engineering calculations. Referring to the pervasive use of steel I-beams,
Khan criticized structural engineers who used excessive factors-of-
safety in conjunction with steel beam standardization. In his view, this
led to overly large member sizes ‘and further limited the field of engin-
eering expression stifling the creation of the more graceful forms which
the stress diagrams indicated.’^7
In the following examples where detailing expresses structural actions,
including bending moment diagrams, two distinct types of expression
may be found. In the first, detailing expresses the variation of structural
actions, and nothing else. In the second type, to use Anderson’s words,
‘The functionally adequate form must be adapted so as to give expres-
sion to its function. The sense of bearing provided by the entasis of144 STRUCTURE AS ARCHITECTURE
▲ 7.23 Carpentry Training School, Murau, Austria, E. Giselbrecht,
- Rear elevation.
▲ 7.24 Web members connect to a truss bottom-chord.▲ 7.25 Face-loads only are transferred
through the plate-rod connection.