It’s a stunning feat of modern engineering. After more than 10 years, the tallest bridge in the UK is finally set to open, and it combines the best in modern construction with historical significance of its neighbouring bridges.
The Queensferry Crossing over the Firth of Forth is north of Edinburgh and connects Lothian and Fife. It is set to officially open on September 4. The new bridge stands next to the original Forth Bridge, built for trains in 1882 and now a dedicated UNESCO historical site, and the original road bridge, which was opened by Queen Elizabeth in 1964, to represent a trio of engineering excellence over the last two centuries.
The Queensferry Crossing has been a long time coming and is one of the biggest transportation building accomplishments of a generation. Stretching 1.7 miles to connect the banks of the Forth, the project has taken 10 years of planning and construction. The 15,000 workers from 24 countries have put in the equivalent of 20 million man hours on the project from start to finish. The bridge reaches 210 metres tall, and the project used 35,000 tonnes of steel, 150,000 tonnes of concrete, and 23,000 miles of steel cabling—enough cable to nearly stretch around the entire equator. Engineers hope the effort put into creating such a mammoth bridge will mean it stands the test of time.
One of the main reasons for a new bridge was to improve the safety and efficiency over the old road bridge. 24 million vehicles cross the old road bridge each year, a large increase from the 4 million when the bridge first opened. The traffic increase has put some strain on the old bridge and contributed to the need for a new bridge that could absorb future traffic growth and stay strong for the future. The new Queensferry Crossing is built with a 120-year design life and two traffic lanes in either direction that are designed to reduce congestion in case of an accident.
The old road bridge was plagued with wind troubles, as high winds would often affect traffic. To fix the problem, the new bridge has wind shields on one side that engineers say will act like a wind scoop to move wind over the bridge without affecting traffic. The new bridge also has a dehumidification system to prevent corrosion and is designed so that cables can be repaired and replaced without shutting down the entire bridge.
But don’t think you’ll be able to take a stroll across the bridge to take it all in—the new bridge will be used solely for private vehicles, while the old road bridge will be used by public transportation, cyclists, and pedestrians. The days before the new bridge is officially opened, 50,000 lucky people will be able to walk across the bridge before it opens to traffic.
In a unique accomplishment for most major engineering projects, the new bridge actually came in costing less than the original estimate. Originally slated to cost £2.3 billion, the final construction total will be around £1.3 billion. However, the bridge is opening later than anticipated; its scheduled opening in December 2016 was delayed due to weather conditions that have slowed construction. With such a big project and so many details to manage, finishing touches are expected to take right until the official grand opening.
“For civil engineers, the chance to build a bridge of the sheer scale and engineering significance of the Queensferry Crossing is a dream come true,” Martin said. “For most of us, it will surely be a once-in-a-lifetime project that, no matter what other challenges we go on to tackle in our careers, will definitely be hard to match. That pride is only increased when we see ‘our’ completed bridge sitting alongside its neighbours, two of the most famous bridges in the world.”