Civil Engineering Reference
In-Depth Information
(ii)
opus africanum
. In the present context it is reasonable to extend the i eld of
this term so as to include its antecedents which were unknown when the term was
coined. h e Romans applied the term to the striking construction they observed
of widespread occurence in the Phoenecian settled provinces of North Africa.
In this region the standard type of wall (both domestic and monumental) was a
pier and panel construction, where the piers, spaced at suitable intervals, were of
i nely dressed stone masonry, while the panels between them were stone masonry
of lesser strength and stability—rubble of varying types. h e integrality of the
wall was ef ected by careful bonding together of the ashlar piers and the rubble
panels (Adam, pp. 130-31, i gs 276-79). h e ef ectiveness of this type of masonry
is evidenced by the numerous survivals to considerable height which can be seen
today all about the countryside. It should be noted here that the dressed stone
reinforcing serves two ends. It directly provides the wall with additional strength
in compression and also it augments the stability, rigidity of the construction by
compartmentalising the rubble and so reducing its outward pressure.
What was unknown to those who devised the term
opus africanum
has been
latterly revealed by 20th century Palestinian archaeology. Although excavation has
been restricted in Pheonecia, in the adjoining areas of Israel and Canaan numerous
examples of this general type of construction have been discovered of Iron Age
date—thus antedating the examples in Punic North Africa (where the construction
remained endemic under Roman rule). As might be expected the Palestinian Iron
Age examples are of ruder construction and the piers of varying degrees of i ne
dressing. Also according to the revealed evidence the Palestinian Iron Age examples
appear to occur in domestic building rather than in monumental building as is
ot en the case in classical North Africa. Nonetheless the device is clearly one and
the same in both regions. In the light of this knowledge perhaps nowadays
opus
punicum
might be a more revealing designation.
Opus africanum
wall construction
is clearly at times on the border line with stone framed construction (cf the Ital-
ian appelative,
opere a telaio
). It would become framed construction if the rooi ng
beams were everywhere lodged on the wall piers, or even more exactly if the wall
piers were all spanned by load bearing architraves. However although examples
of
opus africanum
are preserved to considerable height, few are preserved in situ
to roof level so as to clarify the question.
Rein-
forcing
against
compres-
sive
stress
211-213
150, 151
213
(b) Reinforcing against tensile stress
Walls of buildings ideally are not subject to tensile stresses, however on occasion
they are—obvious occasions being human battery, and, even more patently, earth-
quake shock. In this way tensile reinforcing in walls of buildings in the Ancient
World is usually considered to be a measure directed against earthquake damage.
However it is not evident that provision of tensile reinforcing in walls is limited
to earthquake zones. Perhaps it served against the ef ects of uneven settlement of
