Taphoi wrote:
The Great Buddha Hall (below) in Japan is made of wood, is comparable in scale with Hephaistion's pyre and is 30% smaller than the structure it replaced, when its preceding version was destroyed by fire several centuries ago. It also supports the weight of a massive roof, which would not have been required for the pyre. Furthermore the 'Odate Jukai Dome' is about the same height and breadth as Hephaistion's pyre and built of wood (below). As a scientist and engineer myself I am happy to to assure you that your guess on the maximum size of a wooden structure is quite mistaken.
It is interesting, if somewhat of a complete red herring, that you introduce these two Japanese buildings. By a curious co-incidence I have been in the Todai-ji Temple in Nara, a marvellous structure, more of which anon. Unfortunately, comparing these to the proposed funeral 'pyre' of Hephaistion is like comparing apples and pears. Still, we can point to a few facts regarding them, as Amyntoros has done, to demonstrate that the 'pyre' could never have been built.
Firstly, the Odate Jukai dome. It is a mere very thin shell - a sports stadium - and at 157m long x 153 metres wide (oval shape) and 52m high, and being oval, covers less than half the area of the square 'pyre'. Its roof is a Teflon ultra-light cover so thin as to be translucent in daylight, and its structure is like that of a zeppelin, nothing like the ‘pyre’. The roof trusses are partly steel, with beams made of wood - for which it took 25,000 mature ( over 60 years old) Cyprus trees ! It's only relevance is to give a visual impression of the gigantic size of the proposed 'pyre' - which had more than twice the area at ground level, was at least 7 levels high, and was 20% taller !
The vast amount of wood used for the ultra-light roof also begs the question of the 'palm trunk' roofs, on 7 stories of the 'pyre'. Iraq, of course, has no forests, but date palms had been cultivated for thousands of years. Now a typical date palm grows to maturity in 100 years, to a height of 70-75 ft/23 m or so - but only 50ft/15 m of trunk, with a diameter of 100-200 cm. The total surface area of the 'roofs' is in excess of 200,000 square yards ( depending on the slope of the ziggurat ) or 167,230 square metres. Each palm trunk fills a surface area of 15m long x 2 m wide ( at most) = 30 sq metres or 5,574 fully mature, largest sized, Date Palm trees at a minimum, allowing no wastage ( and we should probably perhaps double or thereabouts to allow for wastage - c.f the 25,000 fully mature Cyprus trees needed to supply beams to the Odate stadium) ! Did this number of
mature date palm trees even exist in and around Babylon at the time ? If so, would the Babylonians have countenanced such destruction ? To this, perhaps, should be added vertical columns about 10 metres long on average ( six internal stories, totalling 60 metres high aprox, allowing a 5 metre seventh story), to support the roof beam/trunks/lintels every few feet, possibly palm or mud-brick. If they were the former so as to burn, then at, say 5 ft or so intervals ( an arbitrary figure merely to obtain an order of magnitude) then 10 aprox would be required for each 'roof beam'/lintel - roughly another 550,000 or so
mature palm trunks !!
(The internal 'compartments' D.S. describes are far too big to support the load of the next story, so more internal walls and/or columns are required)
These numbers, are, of course, hopelessly impossible.
Which brings us to the Todai-ji temple in Nara, supposedly the largest wooden structure in the world - and it is indeed impressive, as I can attest. In its current form it is 57 m long and 50.5 m wide and 48.7 m high, thus it's ground-plan is a little over one sixteenth the size of the proposed 'pyre', and about three-quarters its height. The original was about 30 % bigger, still much smaller than the 'pyre'. Burning down in wartime wasn't its only problem. The original continually sagged and collapsed under the enormous load of the roof, to be constantly propped up - as described in the second of Amyntoros' interesting links, which is why it was rebuilt 30% smaller, and later, the Meiji engineers - western educated - calculated that the structure of wood could never support the load of even the scaled down building. As a result, an imported steel truss, steel bolts and plates, diagonal bracing rods and iron tensioning rods were used in the 'restoration', all cleverly hidden in the wooden structure, and that is why I said 'supposedly' the largest wooden structure in the world. But Diodorus’ pyre did not have a 2,000 tonne roof, as Taphoi points out.
It had no less than
seven roofs. Now
dry palm logs ( the proposed pyre would have used heavier 'green'logs) have a density of roughly 200-500 kg per cubic metre, varying through the trunk. So using an average of 350 kg per cubic metre, our 15 metre log, with a maximum diameter of 200 cm will weigh 15 x ‘pi’ x r squared (1 m) = 47.1 cubic metres, x 350 kg = 16.49 tonnes per log – call it 16.5 for convenience. Earlier I estimated something like 5,574 logs would be needed for the roofs, weighing in at a staggering 91,971 tonnes !!
Oh, and then there’s all those possible wooden pillars, conceivably more than half a million of them.....
Orders of magnitude beyond what a wooden structure could possibly support, obviously, as the Todai-ji Temple demonstrates......
Now, earlier I said that introducing these Japanese wooden structures – the Todai-ji building and the ultra-light roof of the Odate sports stadium was a ‘red herring’ and like comparing apples and pears.
That is because neither structure bears any resemblance whatever to the structure described by Diodorus, which was not a wooden structure like the Todai-ji, or the dome of a sports centre with only an ultra-light covering over wooden beams. Rather, D.S. describes a seven story mud-brick structure far bigger than either, with each story being merely roofed by palm logs, and as the numbers above for solid palm log roofs demonstrate, such a structure is quite impossible.
I should point out that at no time did I refer to the maximum size of wooden structures, because D.S. doesn’t describe the pyre as one.
So this:
" As a scientist and engineer myself I am happy to assure you that your guess on the maximum size of a wooden structure is quite mistaken.”
....is quite incorrect, merely a ‘straw man’ set up by you on the assumption, contra what Diodorus says, that the ‘pyre’ was a wooden structure rather than a mud-brick edifice with wooden roofs. ( and an example of you falsifying what another poster has actually said )
Now, in fairness, I should say that Diodorus’ brief description is a trifle ambiguous and can be translated as the roofs being supported on trunks of palm trees rather than the actual roof being of palm trees – in other words that the roofs were of baked tiles, like the walls, supported on palm log beams. Unfortunately, while that might reduce the number of logs required to, say, a half or one-third of a solid wooden roof on each story ( depending on length of tile), it compounds the weight problem – because mud bricks at 1600 kg per cubic metre are much denser and heavier than wood, so sadly another complete impossibility.
Then there is the time factor that both I and Amyntoros have alluded to. No structure that size could have been built in six months, or even six years, as the building time, and restoration time of the Todai-ji emphasises in the pre-machine age.
I might add that the figure of 1.6 million men working on it is also interpreted as 1.6 million ‘man –days’ of construction, and if that is correct, spread over 9 years is 3285 days and dividing that into 1.6 million gives us an average of 487 men ‘on site’ on any given day....
Taphoi wrote:
We may therefore happily conclude that not only is the account in the ancient sources perfectly self-consistent, it is also perfectly practicable, likely even. It is tragic that the same cannot be said of modern speculation on the matter, which seems usually to be based on instinct rather than evidence or facts.
On the contrary, it is quite clear that the account is quite impossible, whether actual pyre for burning, or subsequent monument is meant,[there are good reasons for thinking actual funeral pyre for burning is being referred to here]. It would seem that, surprisingly, despite your ‘engineering’ and ‘scientific’ expertise, you did not perform even the most rudimentary arithmetical calculations, and it is you that are taking things on trust rather than examining facts or evidence. It is also obvious your ‘engineering’ and ‘scientific’ expertise is not in the fields of civil, structural or building engineering !!
There are other reasons for thinking that Diodorus' account of the funeral 'pyre' is fictional, but this is quite long enough already, so I'll save them for another time....
It is tragic that the same cannot be said of modern speculation on the matter, which seems usually to be based on instinct rather than evidence or facts. 
