Civil Engineering Reference
In-Depth Information
pyramid was i nished i rst, then the middle, and i nally the part which was the lowest
and nearest the ground”. h is statement is now generally interpreted as refer-
ring to “i nishing” in the sense of
in situ
dressing of the casing blocks, where
the mode specii ed would be standard procedure. Nonetheless the appositeness
of the statement to the problem of setting (not dressing) is such that the
(im)possibility of setting blocks from above downwards has received, on occasion
serious consideration.]
Now to consider the alternative approach to building a pyramid,
viz
to raise
it up as a single unit, core and casing together. In this instance it is obvious that
installations are required for carrying on the building operations. Whereas it
may be possible to work casing blocks up the faces of the stepped core blocks,
it is clearly impossible to work all the building material, core and casing blocks
alike, up the narrow steps provided by previously set quarry faced casing blocks.
h us installations are necessary to provide for setting the material even though
the casing blocks are set quarry faced; and in this latter instance, installations are
also required for the subsequent
in situ
dressing of the casing blocks. Given that
the construction of a pyramid necessitated installations of some sort to raise up
the building units, it was assumed that the installations were those attested for the
construction of normal buildings,
viz
haulage ramps, supplemented to a greater or
less degree by steps to facilitate levering. It was also assumed originally that these
installations were installed outside and abutting on the face of the pyramid since
this was the manner for normal buildings.
In these circumstances much thought was devoted to the nature of ramps,
which would serve to raise up blocks in the i nal instance to almost 150 m. Such
ramps moreover had to be lengthened (and strengthened) as they were continually
increased in height (cf D. Arnold,
Building in Egypt
, pp. 98-108).
Initially a direct approach type of ramp was accepted (W.M.F. Petrie, “h e
Building of a Pyramid”; J.-P. Lauer, “Le Problème de la Construction de la Grande
Pyramide”). However continued analysis showed this device to be utterly imprac-
tical. To achieve a height approximately 150 m such a ramp would come to have
the cross section of a pyramid face and a length of a kilometre to a mile. h us its
mass would be greater than that of the pyramid itself. Its operation would also
become disastrously uneconomic as it increased in height. h is arises from the
solid geometry of a pyramid (H.R. Butler,
Egyptian Pyramid Geometry
). h e mass
contained in a horizontal layer of a pyramid diminishes from base to summit so
that the great proportion of the volume of a pyramid is contained in the lowest
portion of its height—e.g. half the volume is contained in the lowest 1/5th of the
height, and two thirds of the volume is contained in the lowest 1/3rd of the height,
while the upper half of the pyramid height contains only 1/5th of the volume, the
uppermost 1/3rd of the height contains only 1/20th of the volume and the upper-
Limita-
tions of
external
ramps
65
66
67, 68
