18 October 2020
The Pont du Gard Aqueduct Bridge – Masterpiece of Ancient Building
The question what have the Romans ever done for us? Was famously asked in the Monty Python film Life of Brian and certainly you might think that a few thousand years later that question is potentially redundant. However, a one look at the Pont du Gard aqueduct bridge may put paid to that idea.
They certainly made things to last. Although the Pont du Gard is no longer a functioning aqueduct bridge, the very fact that it isclose to two thousand years old and still standing is testament to the skills of its builders (although of course it has had renovations over time). The fact that it has gone from being useful to simply decorative is neither here nor there.
The Pont du Gard crosses the Gard river in Southern France. Altogether the aqueduct is over fifty kilometers in length and connects the towns of Uzès and Nîmes. As well as being the highest of all the Roman aqueduct bridges it is also one of the best preserved. Amazingly, no mortar was used in its construction.
It was built in the first century AD so at the time the Monty Python characters were bemoaning the empire the citizens of Nîmes were enjoying a supply of over forty million gallons of water each day. The precision used by the Roman engineers is staggering: despite its length the aqueduct only descends by seventeen feet throughout its whole length.
It was used well after the fall of the Roman Empire, possibly in to the tenth century. However, it was not maintained and eventually clogged up with mineral deposits and the detritus of hundreds of years. Even after its use as an aqueduct dried up its function changed and it became a toll bridge in the middle ages.
It is thought that the construction of the aqueduct started around the year AD 40 and was completed in about fifteen years. There would probably have been around a thousand workers laboring on its construction.
The bridge itself is 274 meters in length and a massive 49 meters high. It was built on three levels and on each level the span of the arches is inconstant. Each one is a slightly different width of span, a deliberate ploy to protect the bridge against subsidence.
The water was carried in a conduit that the Romans called a specus and this was right at the top of the third level. The upper levels curve a little and this too was thought deliberate. The idea was that the engineers did this to make it stronger against the flow of water – 44 million gallons a day causes a considerable amount of pressure.
However, it has recently been shown that the bend was caused by the expansion and contraction of the stones due to the heat of the sun.
It is of course the stone that has given the aqueduct bridge its longevity. There is over 50 thousand tons of stone making up the bridge and many of the blocks weight in excess of five tons each. There is no mortar involved at all – the cut was so precise that the stones fit together by friction.
Sadly, the name of the architect has been lost to time.Tempus Fugit.
