Re: Stonehenge lintel holes | Forum — The Modern Antiquarian

Stonehenge 180

Image by tjj

Stonehenge lintel holes

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Littlestone Dec 20, 2006 17:17:48

Replying to nigelswift

I'm inclined to think the illustration was made to show tenons projecting through to the top surface merely to convey the fact there WERE tenons, which couldn't be clearly shown otherwise.

Good point. Perhaps that also suggests that, at the time the sketch was made, all the lintels were in place.

IMO the actual tenons are actually pretty sophisticated since their "bulbous cone" shape allows for considerable subsequent structural movement without structural failure. I reckon they were very clever people with a long term view.

I'm sure you're right but just one niggling little question - why bother with mortise and tenon joints at all? Wouldn't the weight of the lintels on all of the uprights have provided sufficient stability for the structure? Dunno for sure but even in earthquake-prone countries like Egypt, Greece and Malta mortise and tenon joints weren't used in ancient structures. Seems like an awful lot of trouble to go to at Stonehenge just to replicate earlier wooden structures in stone. Do the mortise and tenon joints at Stonehenge really make that much difference to the stability of the structure?

VenerableBottyBurp Dec 20, 2006 17:38:54

Replying to Littlestone

Evidently the M&T joints were important, not just to the longevity of the structure but to do what M&T joints are intended to do - pull and set the pieces together during construction. The stones were of differing length and whilst to a certain extent this could be taken into account in the ground, the heights would invariably end up different through compaction, you would not be able probably to reset the bigger stones so in order to get them to accept a lintel the tops of the uprights would have to be paired down. Shaping them then ensured the uprights would be pulled into position.

I think...

VBB

nigelswift Dec 20, 2006 18:27:57

Replying to Littlestone

I think there's no such thing as a solid foundation. Buildings sink (and often rise) over time, often differentially, as the ground becomes compacted over a long period - or heaves as the water table or temperature changes - or these things happen repeatedly over different seasons and the sockets wear loose. And then there's Darwin observing fallen stones sinking into the ground due to worms.

How much of all that they were aware of is a moot point though.

The Eternal Dec 20, 2006 22:12:16

Replying to Littlestone

Littlestone,

Littlestone wrote:

[quote]Do the mortise and tenon joints at Stonehenge really make that much difference to the stability of the structure?

Yes, for greater masses the frictional quality of water ingress in joints is greater, and, with the addition of algaeic growth, the friction is reduced further.
Imagine small blocks , say an inch square by four inches long. These, made out of the same materials, wouldn't be influenced as much by the gravitational constant as a greater mass would be, and the osmotic effect of water is greater for a lesser mass. Mortice and tennon joints obviously stop the sliding process, unless the uprights fall.
Add to that the fact that the end pieces were joined in a similar fashion, and the fact that a circular structure is very stable, then, perhaps, that is why Stonehenge has lasted so long.

Cheers,
TE.