Sunday, October 23, 2011

Engineers rule!

So far we’ve seen some pretty amazing engineering feats on our travels. Hong Kong had some awesome bridges and amazing high rise buildings. Almost as amazing as the high rise buildings themselves was the scaffolding around them. In places, buildings over 20 stories high were surrounded with scaffolding formed entirely of bamboo! There were generally no footplates at the base, and the bamboo was tied together with what appeared to be strips of flax or similar. Amazing.

The airport terminal at Hong Kong was also pretty cool. The whole airport is reasonably new (I’m sure you’ve heard about the approach to the old Hong Kong airport, where planes had to fly between skyscrapers and come in to land at about a 30 degree angle!). There are 2 huge terminals, and they both put Christchurch to shame in terms of size. In terms of design and construction, however, I can’t help but feel they pale in comparison…

England also has some pretty cool engineering. Much of it is particularly impressive given its age. We have visited cathedrals in Chester and Worcester, which were both amazing. The ornateness and detail of the buildings is hard to get your mind around – there is nothing even close to it built today. They are particularly grand, with massive ceilings, often ornately decorated themselves. The windows are all stained glass, either like the (former) rose window of Christchurch Cathedral, or featuring depictions of Biblical scenes or saints. Around both interiors and exteriors are statuettes, we figure they are of saints or apostles, and in many cases, they were destroyed for political reasons (i.e. during the civil war), so it is common to see figurines without hands, with faces scratched away, or even without heads, which is rather sad from a historical preservation perspective.

I can see why it took 300 years to finish building the Worcester Cathedral. It is also amazing to see gravestones – or perhaps more accurately, memorial stones - of people who lived 600-800 years ago. The more standard of these are set in the floorstones of cathedrals, worn down by hundreds of thousands of footsteps over time. More impressive stones are set against the walls of the cathedrals, with those from the 1700s being particularly verbose, waxing lyrical about the humility and compassion of the deceased. Some date back as early as the 1200s, though these are mostly in Latin. For us both, the most interesting were those from around 1500 that feature skulls, demon-type faces, and cherubs, among other things. (Can you tell the Historian added some bits into my Engineer's blog post at this part?!)

The highlight so far though has to be Clifton Bridge. Spanning the Avon Gorge in Bristol, this suspension bridge was the first designed by engineer extraordinaire Isambard Kingdom Brunel, in 1829. It is all the more amazing given he was only 24 years old at the time!
Thanks to some speedy driving from Michelle, we managed to get on a tour of the bridge on the Sunday afternoon (Tours are only held at 3pm on weekends, and traffic was thick). I’ll summarise the history briefly, as I found it really interesting.

The idea of building a bridge in that location can be dated back to 1754 when a local businessman made a gift of GBP £1,000 towards a bridge. Unfortunately at the time the technology or knowledge to build a bridge of the required span didn’t exist. By the 1820s however technology had advanced and the need for a bridge was more pressing.
A design competition was held in 1829. The chief judge was the famous engineer Thomas Telford. Funnily enough, when the results were announced, his own design was the winner! This obviously caused a furore, and so the following year another competition was held. By this time, Isambard was in Bristol, having been sent there to convalesce after he injured himself saving workers from a cave in at the Thames Tunnel, which he was constructing with his father Marc.
13 complying designs were received in the second competition, 4 of which were from Brunel. Brunel's design was originally placed second, but he was so upset by this decision that he went back to the judges with further calculations and justifications, and managed to convince them that his design should be chosen.

He did have to make some compromises – the judges made him reduce the span of the bridge, requiring a large abutment at the western end. In the end this abutment comprised one third of the total cost of the bridge. According to the guide taking the tour, it turns out that Brunel was correct, and the bridge could have spanned the full width of the gorge.
Construction began in 1830, but unfortunately was beset with complications. The Bristol riots of 1831 meant that funding for the bridge was withdrawn, and the contractor went bankrupt in 1843 after construction had restarted.
Brunel moved on to other jobs (including designing the world’s largest iron ships, further tunnels and numerous spectacular bridges). Unfortunately the Clifton Bridge was not completed in his lifetime.
In 1862 it was decided to complete the bridge as a memorial to Brunel. Some modifications were made, but it was largely the bridge as Brunel designed it. It opened in 1864 and is still going strong.

View towards Bristol from the centre of the bridge

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