Monday, 23 May 2011

Longest brick arch in the world

Finished in 1838, this spectacular pair of long flat brick arches was contructed by Isambard Kingdom Brunel to carry the Great Western Railway (GWR) over the River Thames at Maidenhead.

At the time of building, and perhaps even now, these arches were the longest in the world built of brick.  Each span is 39m wide and only 7m high.

There is an entertaining 'urban myth' about this bridge.  (Or in context, should it be a rural myth?)  It is said that the board of the GWR (in the typical way of boards who know nothing of engineering but something of litigation) were concerned about the bridge collapsing.  They ordered Brunel to leave the wooden 'formers' in place under the bridge - just in case!  (These formers had been put in place to support the arches while they were constructed of course.)

Brunel (in the typical way of this independent minded engineer who cared little for the voice of authority) complied with their request but lowered the formers slightly so that they took no part in the structure. As you can see - the bridge survived a lot longer than the woodwork which was washed away in a flood, and Brunel was proved right (as usual).

One can only imagine his glee and admire his innovation.  And as you can see from the state of his boots in this famous photo, he was a real engineer!  That reminds me - I ought to polish my shoes as I am not a real engineer.

Little note:  GWR - also known as the Great Way Round by competitors, or God's Wonderful Railway by fans of their stylish locomotive engineering.


Little Miss Joey said...

hahahaha... cunning!
and definitely makes me think of an engineer I know :P

Anonymous said...

The 'Hawkshaw arch' which carried the Lancashire & Yorkshire Railway's Liverpool & Bury extension line over the London & North Western Railway in Liverpool is a brick arch on the skew, allegedly 135 feet wide at one end, widening to around 200 feet at the other. It still exists, although its 60ft height has been greatly reduced as the ground below has been filled in. Its span is much greater than Brunel's 128ft spans at Maidenhead.
Incidentally, the designer, Sir John Hawkshaw, opposed Brunel's 7ft broad gauge on the Great Western Railway in 1838. (He was right, the broad gauge was eventually ripped up in 1892). He drove the East London Railway through the elder Brunel's previously useless Thames Tunnel. And he re-designed Isambard Kingdom Brunel's Clifton Suspension Bridge at Bristol, and raised the funds to complete the bridge as a MEMORIAL to his friend Brunel. Altogether an impressive engineer, but little remembered today.