The daring bridge that rewrote the engineering rulebook 200 years ago
By Julia Buckley, CNN
(CNN) — It was built to ferry horse-drawn carriages across a notoriously wild stretch of water, and was a crucial connection between two island nations during Europe’s industrial revolution.
When it was constructed in 1826, the bridge across the Menai Strait, between the north Wales mainland and the island of Anglesey, was a vision of the future. Suspended between the 1,368-foot gap at a height of 102 feet, this was the world’s first road suspension bridge to start construction. By the time it opened, it was the longest in the world, and remained so until the completion of the Brooklyn Bridge in 1883.
Perhaps more incredibly, the Menai Strait Bridge — or Pont Grog y Borth in Welsh — is still in use, over two centuries later. It celebrated its 200th anniversary on January 30.
“While there are a fair few bridges that have lasted 200 years or more — there are even Roman bridges — none of them look like this,” says Kerry Evans, the chartered engineer who manages the bridge and the modern A55 road around it.
“That expression of freedom in terms of innovation and design to develop a structure — that was absolutely bonkers when you look back now.”
Designed by Thomas Telford, one of the earliest civil engineers in history, the bridge didn’t just connect Anglesey to the Welsh mainland; it was also part of a network that linked two capitals, Dublin and London. A law passed in 1800 had officially united Ireland with Great Britain, creating the United Kingdom, and there was political pressure to build easy transport links between the capitals.
Ferries ran from Dublin to Holyhead, on Anglesey; but crossing from there to the Welsh mainland, also by ferry, was notoriously tricky. The Menai Strait was known for its currents, and crossings were often canceled. Anglesey farmers, known for their cattle-breeding, would drive their herds across the strait themselves, often losing animals to the waves. What’s more, the ferrymen would take advantage of passengers. “They blackmailed people — if the tide was coming in, they’d put up the price,” says William Day, a retired civil engineer and North Wales resident. It wasn’t the sophisticated, well-oiled system that a rapidly expanding empire sought to portray.
In 1815, the government voted to construct a road from London to Holyhead. Telford — a Scot who’d made a name for himself constructing canals and roads in the Midlands, at the heart of the industrial revolution — was employed to build it. And one of the last parts of that road — which ran through cities from Birmingham to Shrewsbury — would be the crossing of the Menai Strait.
Telford picked the shortest crossing, says Gordon Masterson, former president of the Institution of Civil Engineers, and current chair of the Panel for Historic Engineering Works. So far, so regular. But then he made a startling choice for the 1,300ft wide span. Instead of planning a regular viaduct-style bridge, with columns marching across the water, embedded in the seabed, he planned a structure that floated above the strait, tethered to the land each side.
“That was the bold choice,” says Masterson. “Spans of this nature had never been done before.” In fact, at 1,368 feet, the deck he designed was two and a half times longer than what had been tried before on a road suspension bridge, he says. A traditional viaduct would have been more expensive to build, and could have obstructed shipping traffic. “Clearing the whole gaping broad sweep was his brilliant concept,” he says. “It was a shot to the moon in terms of civil engineering.”
“It set a standard for a very long time,” says Day, who has worked on the bridge on various projects. “That standard is still with us in many ways. It had a marked impact on engineering and society.”
The first stone was laid on August 10, 1819. Arches — made from limestone from the eastern tip of Anglesey and embedded int the rockface — tiptoe out from either side, with twin towers on either side of the strait, each rolling the deck out across the void.
The 577-foot deck was held in place by 16 chain cables, each 1,714 feet long and made from 935 wrought iron bars, clocking in at 121 tons each.
Telford sourced the iron from his longstanding collaborator, William Hazledine, who he called “Merlin” in a reference to the seemingly magic qualities of his iron. Each link was identical so that they could be interchangeable and replaceable. “That was mass production long before we even thought about the word,” says Day. The same went for the entire London to Holyhead road. Day says that depots were stocked with repair materials, rather like aircraft parts being kept at airports today. A repair done in situ was a repair done faster.
By the time the bridge was finished, in 1826, it was no longer the first road suspension bridge in the UK. That plaudit had gone to the 449ft Union Chain Bridge across the river Tweed in Scotland, unveiled in 1820 — which is also still in use today.
But the Menai Bridge’s sheer size made it unlike anything that had been built before. “How stunning it would have seemed to everyone watching this thing appearing across the strait,” says Masterson. “It would have seemed like some wizard was working with skills people could only dream of. Nothing had been seen on that scale before, anywhere. It would have been jaw-dropping.”
Forward-thinking Telford didn’t just want to build any bridge — he wanted to make a beautiful addition to the landscape. “The shape of the bridge is beautiful,” says Day. “The curves are very aesthetic, the towers and piers are coming up from rock outcrops.”
The bridge opened on January 30, 1826, to immediate fanfare. “The night it opened, they had the post coach arriving at the inn, expecting to catch the ferry,” says Day. “It waws a stormy night and the engineer on site said, ‘You’re going over the bridge.’ The passengers onboard were relieved, as they weren’t looking forward to the ferry. At 1.30 a.m., the coach went across. After that, people were flocking to the bridge.”
It wasn’t just a link to Anglesey; the route from Dublin to London took off, too. “Telford probably did more for unifying Britain than the treaties,” says Masterson, noting the engineer’s work improving the roads and harbors of Scotland, too.
“His North Wales Road was instrumental in improving the bonds between Ireland and England — trade, commerce and politically and socially.”
The road with its bridge encouraged immigration, and Irish workers flooded into England to build canals and roads. Trade increased, and mail traveled quicker between the countries. In 1850, the Menai bridge acquired a sibling: the Britannia railway bridge, or Pont Britannia, which was upgraded to allow car traffic in 1980. But Telford didn’t live to see it, dying in 1834 at the age of 77. During his lifetime he had built over 1,000 bridges, 1,000 miles of roads, as well as dozens of canals, ports and harbors across the UK. He had been appointed the first president of the Institute for Civil Engineering, and his influence had earned him the nickname, ‘the Colossus of Roads.’
Meanwhile, the bridge instantly became a tourist attraction. “It was a wonder,” says Day. “people were coming just to visit, and that still happens to this day. I’ve stood there and watched people pull up, take photos, talk about it and go off again.”
A local icon
Today, the bridge is going strong. While the iron was replaced with steel and a new deck was added in the 1930s, the limestone pillars are original. “You can see the tooling marks on the stone, where it was cut from the quarry face,” says Day, who has worked up close on the bridge. Other original elements that are still in use are the concrete cobbles that Day’s team discovered during one set of renovation works. “The state of the masonry on the mortar is remarkable — almost unaffected,” he says. Telford started out as a stonemason, and Day reckons the high standard of craftmanship is down to his background. “He had the skill and knowledge of how stone could be used,” he says.
As the manager of the bridge — and the first woman to oversee it in 200 years — Evans gets up close and personal to it on a daily basis, and is constantly surprised by the technical details. “I’m in awe of it,” she says. “When you stand at the base of it, you can’t really fathom how someone imagined that.”
Working on a 200-year-old structure isn’t easy. Not only do they have to balance the requirements of modern traffic on a bridge built for horse-drawn carriages — there’s a 20mph limit on the bridge, and currently a 7.5 ton weight limit — but they also make discoveries, and have to piece together the reasons behind it. “Between each masonry block is an iron pin, and it was only by checking on the engineers’ diaries from 1824 that we realized they were concerned about lateral movement,” she says. What’s more, locals take a keen interest in any work that needs to be done: “If it was a bridge anywhere else, people wouldn’t bat an eyelid, but there’s a huge emotional attachment to it, and there’s nothing like it anywhere else in the world.”
Day agrees that it’s “challenging” working on a historical structure. His past projects have included removing glass panels added in 1938 and replacing them with steel decking. Every change they made had to be approved by Cadw, the Welsh government’s historic environment service. “Looking at the engineering imperative on one hand and the historic reference — it’s an interesting balancing act,” he says, adding that he jumped at the opportunity to work on the bridge when it arose. “It’s quite something to be able to add to your CV,” he says.
Not surprisingly, the bridge has become a tourist attraction in itself. “It’s a really exciting experience to drive between the two piers over that water a long way down,” says Masterson. There’s a visitor center on the Anglesey side — where the town is called Menai Bridge, no less.
The bridge has become so firmly rooted in the British psyche that “Operation Menai Bridge” is the official codeword given to the preparation for the eventual death of King Charles III. (His mother’s death was prepared for with the code Operation London Bridge.)
The bridge had an instant effect on the communities it connected when it debuted, but 200 years on it is still an icon for locals.
“There’s a huge emotional attachment to the bridge,” says Evans, a fellow of the Women’s Engineering Society, who grew up locally. “You wouldn’t think 300 million-year-old limestone with steel on it would have that very physical and emotional connection to people, but it does.” Although she doesn’t think that her childhood relationship with the bridge prompted her to become a civil engineer — only 8% of them are women — she does remember childhood drives on a Sunday morning around the area.
Day, a bridge engineer who moved to the area from England in 1998, has absorbed the part that the bridge played in his in-laws’ history. His wife’s mother was born on Anglesey, and her father on the mainland. “It’s quite a common story, a relationship across the strait,” he says. “Over time, the bridge has become an essential link. It’s devastating when it’s closed for any reason.” Crossing it is a daily occurrence for most people in the area, he says — but even so, “it’s seen as an icon.”
Evans thinks it has only got more important for the community since the pandemic. “After lockdown, being able to cross the Menai Strait Bridge symbolized freedom, connectivity, family,” she says.
And two centuries on, she says, it’s a point of pride for rural North Wales. It was that pride that was behind the 200th anniversary festivities that took over the bridge in January.
“Although they were doing stuff like this all over the world, or were starting to, we did it here first in North Wales,” she says.
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