Editing Trajan's Column (section)

== Construction ==
{{See also|List of Roman monoliths}}
[[File:1586 Rome obelisk erection.jpg|thumb|Erection of the [[List of obelisks in Rome|Vatican obelisk]] in 1586 by means of a lifting tower. A similar arrangement was presumably used for the construction of Trajan's Column, but with less available space and thus manpower.]]

It is assumed that the column drums were lifted by [[crane (machine)|crane]]s into their place.<ref name="Lancaster 426-428">{{harvnb|Lancaster|1999|pp=426–428}}</ref><ref name="Jones 34-36">{{harvnb|Jones|1993|pp=34–36}}</ref> Ancient sources, as well as a substantial body of archaeological evidence, show that [[Roman engineers]] were capable of raising large weights clear off the ground. The typical drum of Trajan's Column weighs c. 32&nbsp;t,<ref name="Jones 1993, 32">{{harvnb|Jones|1993|p=32}}</ref> while the [[Capital (architecture)|capital]], the heaviest block above the base and pedestal, is even at 53.3&nbsp;t, which had to be lifted {{Cvt|34|m}} high.<ref name="Lancaster 426-428"/> To save weight, the treads had probably been carved out before either at the quarry or ''in situ''.<ref name="Jones 31"/><ref>{{harvnb|Lancaster|1999|p=424}}</ref>

Even so, for such loads, the typical Roman [[treadwheel]] crane, which could only reach a maximum height of {{convert|15|to(-)|18|m|ft|abbr=off}} in any event, was clearly inadequate.<ref name="Lancaster 426-428"/> Instead, a tower-like wooden construction was erected around the building site, in the midst of which the marble blocks were raised by a system of [[pulley]]s, ropes and [[Capstan (nautical)|capstans]]; these were powered by a large workforce of men and possibly also [[draught animal]]s, spread out on the ground.<ref name="Lancaster 428-437">{{harvnb|Lancaster|1999|pp=428–437}}</ref> According to modern calculations, eight capstans were needed to hoist the 55&nbsp;t base block, while the length of rope required for the highest drums measured some {{convert|210|m|ft|abbr=off}} assuming two-block pulleys.<ref>{{harvnb|Lancaster|1999|p=435}}</ref>

Such a lifting tower was later also used to great effect by the [[Renaissance]] architect [[Domenico Fontana]] to relocate [[obelisk]]s in Rome. From his report, it becomes obvious that the coordination of the lift between the various pulling teams required a considerable amount of concentration and discipline, since, if the force was not applied evenly, the excessive stress on the ropes would make them rupture.<ref>{{harvnb|Lancaster|1999|pp=436–437}}</ref> In case of Trajan's Column, the difficulties were exacerbated even further by the simultaneous work on the neighbouring Basilica Ulpia, which limited the available space so that the capstan crews had proper access only from one side.<ref>{{harvnb|Lancaster|1999|pp=430–431, Fig. 9–10}}</ref><ref>{{harvnb|Jones|1993|p=35}}</ref>