Civil Engineering Reference
In-Depth Information
Installations for clean lit ing building units to any designed position were the
formative factor of Classical Greek building site development;* and a consider-
able amount of information relating to them has come down from antiquity (for
a compendium v Orlandos II, pp. 31-44). It may be classii ed as follows:
Clean
lit ing
(1) Material remains of such devices. h is is very slight and is limited to several
pulley blocks (cf Hesperia, 38, 1967, p. 590, i g 1, pl 76).
(2) Indirect material evidence for the use of lit ing devices by way of cuttings and
protruberances on blocks of masonry designed to facilitate the attachment of
blocks to the lit ing mechanism. Such evidence is endemic in classical ashlar
masonry from the later 6th century BC onwards. Be it noted however that the
absence of such cuttings etc. on blocks is not conclusive evidence that lit ing
devices were not employed in their handling. Attachments can always be made
by slings and tieing with ropes (cf Martin, pp. 209-19).
(3) Ancient representations of lit ing devices. A certain number of reliefs and
one or two mural paintings, all of Roman date, depict various forms of lit ing
devices (cf Orlandos II, i gs 21-26).
(4) Ancient written records. A surprising amount of literary and epigraphic refer-
ence to lit ing devices exists. Its main divisions are as follows:
a) References in Greek building contracts and other building inscriptions
(v Martin, p. 202).
b) Expositions in Hellenistic treatises on mechanics preserved in Arabic trans-
lation (Hero of Alexandria, ed. Nix Schmidt, Leipzig, 1900).
c) Discussion in Roman building manuals (Vitruvius X.II).
82, 83
95
93
84, 88,
89
It might be thought that with such documentation available the functioning of
clean lit ing devices on Classical ashlar building sites would be clearly apprehended.
However this is absolutely not so—and on two basic counts: their mechanical
operation and their exploitation within the site organisation.
A clean lit ing device (crane, hoist etc.) comprises two distinct elements: the
mechanical contrivance which facilitates the application of vertical traction sui -
cient to raise up a heavy burden (pulley, sheaves, block and tackle); and the hous-
ing, mounting for this mechanical contrivance. It will be seen that both elements,
jointly and severally, provided for the functional requirements as listed above. h e
machinery plus the frame jointly were required to withstand all stresses induced
* It is an obvious surmise that the application of block and tackle to Greek building operations had its back-
ground in ships and shipping, since the sea was characteristic of Greek life. h e backstays and the halyards to the
masthead is a paradigm of the crane in antiquity. Furthermore, all substantial cargo ships required derricks for
loading and unloading cargo. However the transition from ships to building sites was not a matter of course. Both
the Egyptians and the Phoenecians sailed well rigged ships, but there is no evidence that they likewise developed
clean lit ing devices for building construction.
