How to Build a Bridge: Steps and Examples

August 12, 2022

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Blackfriars Bridge spans the River Thames in London

Bridges are one of the great marvels of the world, made possible by civil engineering. Many ancient bridges still stand today as proof that, when built properly and with sturdy materials, a well-constructed bridge can last millennia. The Pons Fabricius in Rome, built in 62 BC, is still in use today.

However, without proper construction and maintenance, modern bridges can wear easily, becoming safety hazards and traffic impediments. About 220,000 bridges in the United States need repair or replacement due to structural deficiency and erosion, according to the American Road & Transportation Builders Association. By earning an advanced engineering degree, such as a Master of Science in Civil Engineering, individuals can gain a solid theoretical foundation in engineering and the technical skills they need to become innovators, with the potential to build the great bridges of the future.

How Are Bridges Built?

For those wondering how to build a bridge, the first step is always preparation. For bridges on land, such as over chasms or canyons, professionals working in construction engineering survey the potential site for proper building conditions, checking specifications such as the soil strength and the depth and layout of the land. They then use engineering software to build simulations of the bridge and test them under different weather and weight conditions to determine the best structure. Civil engineers design bridges and supervise their construction.

Following are some common bridge structures:

Arch bridges balance compression and act as a bracer against heavy winds.
Suspension bridges use cables hung from suspenders to support the deck of the bridge and use piers to balance the compression.
Truss bridges use diagonal beams or chords to support tension across the bridge.
Cantilever bridges use upper and lower chords separately to balance tension.

Once the type of structure has been selected, builders begin installing the foundation at the chosen stable location. They drive piles into the ground to create a platform, then build a tower on top of this platform that will serve to support the rest of the bridge. They build upward from the piles until the tower reaches the designed bridge height, usually using concrete and steel along with other materials.

After the stabilizing towers are completed, builders move on to the superstructure, which includes the cables, beams, and latticework that will support the bridge. To remain stable, a bridge must balance its own tension and compression, which are affected by weather and traffic traveling across the bridge. This is why choosing the right bridge structure for the specific conditions of the bridge location is so important.

Sometimes a bridge that might seem like the optimal choice isn’t feasible in certain circumstances. For example, while arch bridges are extremely strong and long lasting, they are more expensive, more difficult, and more time-consuming to construct. Working efficiently and safely is an important aspect of a civil engineer’s role.

When a bridge spans water, while much of the process remains the same, additional elements must be considered during design and construction. If the bridge is being built over deep water, it can be impossible to drive piles into the soil safely and properly, so watertight enclosures called cofferdams are lowered into the water. Once they are installed, the water is pumped out of the inner area, creating a safe and dry space for workers to build the bridge.

Amazing Bridges Around the World

Innovative new materials, methods, and technologies are opening the door to creative new ways to design, build, and reimagine amazing bridges around the world. From new projects where civil engineers work with architects in designing futuristic bridges to the modern and environmentally sustainable new ways engineers are repairing failing infrastructure, a broad range of exciting new opportunities is available to engineering graduates.

Around the world, architects and civil engineers work hand in hand to push the boundaries of what is possible, while remaining true to what is practical, functional, and safe for use. By pursuing an advanced degree in civil engineering, students can focus on the areas of the field that inspire them the most. They can build on the foundational skills from their undergraduate degrees, acquire the knowledge to take on more challenging roles and build the confidence to chase their professional goals.

Below are some examples of futuristic bridges that represent the best of civil engineering.

1. Rolling Bridge

The Rolling Bridge is a pedestrian bridge on an inlet at the Grand Union Canal in London. Designed by Thomas Heatherwick in 2004, the bridge features an innovative design involving a unique rolling movement as an alternative to a drawbridge. Where bridges that open to let boats pass have typically featured single-section elements that separate and lift, the Rolling Bridge uses a coiled octagonal structure that methodically uncurls into a traditional straight bridge. This allows pedestrians to walk across the bridge when it is expanded and boats to pass through when it is contracted. The Rolling Bridge won several awards, including the Structural Steel Award and the Emerging Architecture Award.

2. Blackfriars Bridge

Across the River Thames in London spans the largest solar-powered bridge in the world. Covered with 4,400 photovoltaic solar panels affixed to its roof, the Blackfriars Bridge provides half the energy for the adjoining Blackfriars rail station. The solar installation could reduce the carbon emissions of London’s Blackfriars railway and public transit station by approximately 511 tons per year, according to First Capital Connect. Solarcentury, the firm responsible for installing the solar panels, developed the bridge as a source of renewable energy and an inspiration to other cities in their efforts to become sustainable.

3. Tail Bridges

Bridge designers in the Netherlands created the tail bridge. It is a solution to the high levels of boat traffic in local waterways passing under bridges that must lift and lower over small rivers. Tail bridges are able to raise and lower from one pylon, as opposed to the multiple hinges that are common on larger drawbridges. Fast-moving tail bridges, such as Slauerhoffbrug in Leeuwarden, can quickly move out of the way for passing boats while only briefly impeding road traffic.

4. Millau Viaduct

The Millau Viaduct is one of the world’s tallest bridges, with its highest tower measuring 1,125 feet above the ground. This marvel is a record-breaking feat of bridge architecture, spanning 1.55 miles across the valley of the Tarn River in France. A visually stunning bridge, it is composed of eight cable-stayed spans and allows for a direct motorway route from Paris to Barcelona.

5. Leonard P. Zakim Bunker Hill Memorial Bridge

This Boston bridge is the world’s widest cable-stayed bridge, designed to transport 10 lanes of traffic. The only cable-stayed bridge in the U.S. considered a hybrid for its use of steel and concrete, it stretches 1,432 feet long, enabling access to and from Boston from the north. In addition to its innovative design, the bridge has a special symbolic meaning. It is named after civil rights activist Leonard P. Zakim and is dedicated to the Americans who fought at the Battle of Bunker Hill during the American Revolution. Christian Menn, a bridge architect from Switzerland, designed the bridge with towers in the shape of inverted Y’s, mirroring the Bunker Hill Monument in nearby Charlestown.

6. Tullhus Bridge

The Tullhus Bridge in Norrköping, Sweden, was designed by the architectural firm Erik Andersson Architects. It boasts a unique creative feature designed to keep cyclists and pedestrians warm during the cold Swedish winters. A hot-air system built into the bridge is equipped to melt ice and snow and heat the walkway. The use of heated air and a custom hourglass-shaped design make the bridge unique. An LED lighting system built into the handrails illuminates the walkway at night. The snow-free bridge keeps cyclists and pedestrians safe while providing access to the city center.

7. Sheikh Rashid bin Saeed Crossing

Also known as the Sixth Crossing, this proposed bridge in Dubai would be the longest arch bridge in the world, with a total length of 1.6 kilometers or 5,200 feet. The ambitious structure would have 12 lanes — six in each direction. The Dubai Metro Green Line would run through the center of the bridge, allowing for as many as 20,000 vehicles and 23,000 metro passengers to cross per hour.

Build Bridges with a Master’s Degree in Civil Engineering

Engineering feats made possible by advanced technology and innovation are at the heart of modern bridges. With sustainable materials, renewable energy sources, and passionate visionary thinking, modern civil engineering accomplishments can inspire the next generation of engineers who are learning how to build a bridge to the future.

Civil engineering involves far more than simply planning and building a project. Through creativity, the evolution of new technologies, and the opportunity to push boundaries, passionate civil engineers can change our landscape. For beginning engineers, exploring the bridges around the world can function as a learning opportunity and career inspiration.

For more than a century, Ohio University’s Russ College of Engineering and Technology has been teaching engineers how to create for good — how to engineer a better future through responsible and sustainable design. With its flexible and innovative program that allows students to specialize while learning from industry professionals, the online Master of Science in Civil Engineering program from Ohio University was created to provide talented new professionals with the skills to succeed in the workforce.

The fully online program is designed to give students the resources to effectively supervise, plan, design, construct, and operate the structures essential to connecting the modern world.

Discover what you can do with a rewarding career in civil engineering and an advanced degree from Ohio University.