Column
The Howard Roark of Engineering
By Jeffrey Perren
Jun 30, 2008

Who was Isambard Kingdom Brunel?

Brunel is not well known outside the UK today, which is an injustice. For though he stood barely over five feet high, he is one of history’s giants.

His achievements in the mid-19th Century are the stuff of romantic fiction. Yet his dazzling feats of engineering were very real and many are still in use today.

Born in 1806 in Portsea, England, Isambard was the son of a noted British engineer, Marc Brunel. His father sent him to study in France in 1820, then the world’s center of the most advanced mathematics and engineering schools.

Brunel returned to London in 1822 and immediately went to work for his father for the next six years, chiefly on the Thames Tunnel. Indications of his love for innovation were already present, even on this project — begun when he was still less than 20 years old.

He was one of the first to embrace the use of Portland cement, invented in 1824. (It has remained through the generations, only modestly changed, one of the most basic building materials on the planet.)

Just how prescient he was to select it was recently proven once again. A structure associated with the tunnel near the docks in Bristol was unearthed recently. It had virtually no weathering at all and was still supporting a massive slab after 180 years near the salt air of the British Atlantic.

In 1828 Brunel stopped work on the tunnel after being injured rescuing several workers during a flood.

Ever restless, while convalescing he entered a competition to design the Clifton Bridge — proposed decades earlier to span the 700-foot (213m) Avon Gorge. At the time, the largest suspension bridge was the Menai in North Wales, covering just under 600 feet (176m) between supports.

Unfortunately for Brunel, the Menai’s designer, Thomas Telford, was judge for the contest and the older man rejected all of Brunel’s designs in favor of his own. Three years later, amid corruption charges, new judges were appointed and Brunel’s design won hands down.

Clifton Suspension Bridge

Apart from its sheer beauty (as evidenced by the photo), there are several innovative elements in the bridge’s design. Just one example is the design for the supports for the wrought iron chains that hold up the deck. (Wire cabling, first used in 1823, came into common use later.)

In order to absorb the extra force of load as traffic crossed the bridge, Brunel invented roller-mounted saddles to hold the suspension chain. They move less than 1mm, about the width of a pencil lead, and without them the extra stress would damage the supporting tower. The chains themselves are anchored in tunnels in the rock, 60 feet (18m) deep and support 1,500 tons.

Though completed in 1864 and designed for horse-drawn carriages, it still stands up to 21st century auto traffic. Up to 12,000 cars per day cross it safely.

One of Brunel’s most well-known achievements is the Great Western Railway (GWR), built to link London to Bristol. He was appointed chief engineer in 1833 and completed the road in 1841, building over 120 miles of track and a dozen tunnels and viaducts along the way.

As part of the effort, he devised a method for nearly doubling the speed of existing rail traffic from the then-standard 35 mph (58 km/hr) to over 60 mph (100 km/hr).

His innovation consisted of devising a practical broader gauge of track to lower the center of gravity of the car to allow for larger wheels. At the same time, it made possible a more comfortable ride in larger carriages and more cargo space for freight cars.

The proposal met with fierce opposition, however, since the track width around England at the time was narrower. Ultimately, economics and other factors caused his innovation to be phased out, but not until long after Brunel had proven his point by completing the rail as designed in 1841.

During the same period and as part of the project, he designed the still-in-use famed Box Tunnel. At nearly two miles long — then the longest railway tunnel in the world — it took six years to complete, claiming 100 lives in the process.

It began construction in 1836 and when the two crews working from either end finally met, they were only one-and-one-quarter inches out of alignment. This was over 30 years before the first subway tunnel in New York was dug.

Isambard Kingdom Brunel

Among other notable GWR structures still in use is Brunel’s Maidenhead Railway Bridge. A beautiful red-brick structure, its arches were the widest and flattest in the world. The spans are 128 feet (39m) long with a rise of only 24 feet (7m).

The low gradient gives the bridge an elegant look and made train passage easier. (Locomotives require more power and consume more fuel on gradients, a serious consideration at the time of early coal-powered engines.)

Not surprisingly, there were doubters about its structural strength. Brunel was ordered to leave the wooden construction frame in place to provide extra support for passing trains.

Confident of his work, he had workmen lower the beams just enough to eliminate any support value but still look as if they were in place. When a flood washed the planks away — but the bridge remained — Brunel’s claims were finally accepted.

But, as the saying goes, the innovator was just getting started.

In 1837, with the GWR still in progress, he designed the SS Great Western, a ship driven by wooden paddle wheels and the first steamship to offer regular transatlantic service. It was also to be the largest ship in the world.

Because of its unprecedented size the GWR backers refused to fund its design. Many argued that it couldn’t carry enough coal to make the journey. But Brunel saw, as his contemporaries did not, that while the capacity of a ship increases in three dimensions, its water resistance increases in only two. That implied that a larger ship could be more fuel efficient.

When the Great Western made its maiden voyage in April, 1838 it missed by only a few hours being the first steamship ever to cross the ocean. Taking only 15 days, however, it made the trip faster than any ship ever had.

In 1843 another Brunel first took to the sea: the SS Great Britain. It was so mammoth it had to be fastened together with over three million rivets, used to connect 30,000 wrought iron plates. The ship was so large the engineer had to invent new methods of launching a ship from drydock. It took 21 hydraulics over three weeks to get it into the water.

But the real innovation lay in its method of propulsion. It was the first ocean-going iron ship with a screw propeller. Brunel’s propeller design was a feat of genius. It was so efficient that even contemporary designs, aided by supercomputers working on advanced hydrodynamic equations, have only improved upon it by five percent.

Still, the great engineer was just getting warmed up.

Plaguing long steamship travel during the time was the problem of fuel. It took enormous quantities of coal to power the steam engines and there were few refueling stations between Bristol and New York at the time. (That’s still true, actually.)

Brunel was determined to design a steamship that could carry all the coal it needed for a round trip as far as to and from Australia.

Great Eastern launch attempt

His fertile mind tackled the problem and in 1852 he designed the SS Leviathan, later renamed the SS Great Eastern.

At 689 feet long and 84 feet wide, the Leviathan was five times larger than anything of its day.

Fifty years would pass before a larger ship was built. Yet it could still do over 13 knots. Even contemporary cruise ships rarely do much more than 20–24 knots.

In order to achieve the sheer size of the ship and its parts, Brunel developed dozens of innovations. Shipbuilders of the day were used to working with wood, which imposed natural limits.

With his experience on railways and iron bridges, he was able to go beyond the conventions of his time, to establish new ones.

Engines of the time, for example, could only produce enough power to propel standard-sized ships. To solve the problem, Brunel built an engine room with 10 boilers fed by 100 furnaces that powered the engines. One produced 3,400 hp for the nearly 60-foot paddles, while another supplied 4,900 hp for the single gigantic screw propeller.

The ship carried not only 5 funnels, but six sailing masts with over 18,000 square feet of sail as backup.

The ship had capacity for over 3,000 passengers — a large number even for contemporary cruise ships. They could have a ride unmatched in safety at the time, thanks to a double iron hull and twelve watertight compartments, more Brunel innovations.

They also enjoyed gas lamps in the cabins, another first for a cruise ship of the day.

Regrettably, due to the huge costs of building it, the ship’s sponsoring company went belly up. Bought by another and renamed, the Great Eastern finally achieved its maiden transatlantic voyage in June 1860, with only 38 passengers onboard.

It later gave a ride to a then little-known writer named Jules Verne. The voyage inspired him to write his 1871 novel The Floating City, accurately summing up the great ship. In 1866 it would achieve even greater fame by laying the second transatlantic cable, averaging 120 miles per day while spooling out the wire.

Sadly, Brunel didn’t live to see it. He had died young, of a heart attack, in September of 1859.

Daniel Gooch, himself a great Nineteenth Century engineer — among other things he laid the first transatlantic cable — wrote of Brunel:

The commercial world thought him extravagant; but although he was so, great things are not done by those who sit down and count the cost of every thought and act.

That gives some insight into his character. More can be gleaned from the fact that Brunel had no interest in being knighted, but enthusiastically became President of the Institute of Civil Engineers.

But to see him clearest one has only to look at his work. There one sees extravagance of a whole different order, and of just the right kind.