Isambard Kingdom Brunel

Yes indeed a great engineer:

There can be no greater tribute to Britain’s most inventive engineer,
Isambard Kingdom Brunel, born 200 years ago tomorrow, than the fact
that so much of what he created is still in everyday use. When
travellers catch the train to Heathrow they leave London under the
great roof of his Paddington Station. If they head for Bristol on the
Great Western line, still one of the country’s fastest, they travel
over his bridges, through his tunnels and arrive at his Temple Meads
station. When travellers cross under the Thames on the tube in east
London they do so through a tunnel he engineered (and in which he
nearly drowned when the river flooded in). His Clifton bridge in
Bristol and Saltash bridge into Cornwall are both still busy and among
the nation’s most spectacular.

Although, although. I remember walking along the Kennet and Avon canal, going from Bath to Bradford on Avon, with my father, an engineer. At times you go alongside his Great Western line (Brunel’s that is, of course). I said something about how great he was because he built the bridges for 200 tonne trains and now they were used by 2,000 tonne ones and they hadn’t had to be changed. Wasn’t that great!

Err, no, not really came the reply. It actually shows how wasteful an engineer he was. He either grossly over-specified or didn’t actually know how to calculate the tolerances properly.  A truly great engineer would have built then only just strong enough for what they were planned to carry.

7 responses

  1. Ed Snack Avatar
    Ed Snack

    Isembard didn’t design the Thames tunnel, that was his father, Marc, although isembard worked on the tunnel. And as regards the bridges, perhaps he at least in part anticipated heavier trains. It would have been a truly wasteful engineer who designed bridges that would have been out of date in 10 years. Given Brunel (the youngers) visionary outlook I am inclined to think he allowed for expansion in the traffic rather than careless overengineering.

  2. It is also worth noting that people were less sure of structural strength in the 19th century. Clearly they did better than people did a century before but they were still unclear on the strengths of various materials and hence prefered to over-engineer rather than see the bridge fall down in a heap (think Tay Bridge for when they under-engineered).
    The best (worst?) example of over-engineering is the first iron bridge which treated iron as it if were wood.

  3. I sincerely hope that the bridges we build today are also being over-engineered. I find the thought of driving across something that’s only JUST strong enough very very scary indeed.
    Especially when you’re stopped dead still on it in a traffic jam boxed in by heavy lorries.

  4. dearieme Avatar
    dearieme

    although, although indeed. Great chap, but I doubt if he was our “most inventive engineer” and he certainly wasn’t our most important – that must surely have been James Watt. But there are no photos of Watt and I doubt that there are any photos of any engineer as striking as the wonderful one of Brunel.

  5. I doubt that there are any photos of any engineer as striking as the wonderful one of Brunel.
    Ahem.

  6. Sorry if I’m missing something absolutely obvious here, but given that Brunel was committed to hugely enlarging the load capacity of the transport of his day, isn’t it reasonable to suppose that built his bridges with that in mind?

  7. The Remittance Man Avatar
    The Remittance Man

    Dug from the dim memories of my structural ebgineering lectures. Bridges are built way stronger than efficient design would suggest for one simple reason. An efficient 200 ton bridge often bends alarmingly when a 200 ton load is applied. It will carry the load, but the users will get very, very nervous.
    We must also consider that rarely does a bridge take the whole length (and hence weight) of a train. Thus the actual load could well be less than 2000 tons.
    RM

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