How many times have you driven across a bridge this week? Chances are, you don't know the answer—bridges are such an intrinsic part of our infrastructure, most of us barely notice them. Despite that, there are a few bridges that stand out, whether it's due to their looks, or the unique engineering that allows them to exist in the first place. Here are some of the world's most famous bridges, and the secrets behind them:
Dubbed “America's Scariest Bridge,” the Chesapeake Bay Bridge-Tunnel is a bridge and tunnel network that spans a whopping 17.6 miles. It crosses the mouth of the Chesapeake Bay, and connects Virginia Beach to Cape Charles, Virginia. This bridge was designed to stand up to the threat posed by hurricanes, nor'easters, and other weather phenomena unique to the area, including a severe storm in 1962 that destroyed a significant portion of the bridge-tunnel and the specialized equipment needed to complete it.
To build it, engineers had to first determine where the ground was most stable and able to support a structure of this length. Because of this, the bridge-tunnel follows a curving path. For the bridge portions, a pile driver drove concrete supports deep into the ground under the water. Once positioned, they were then cut to size and filled with sand and concrete to keep them in place. After this, the bridge was built segment by segment using floating platforms.
The tunnel portions were built by digging a large ditch, then using barges with cranes to lower pre-fabricated portions of the tunnel. These were filled with water to help them sink, and secured together by diving teams before the water was pumped out to make them usable.
Since it's not a suspension bridge, and doesn't rise very high over the water, the Chesapeake Bay bridge-tunnel gives drivers the feeling of driving over the surface of a nearly endless sea. For people who don't like bridges, tunnels, or open water, it's definitely a scary experience!
The Chesapeake Bay Bridge-Tunnel is not just an engineering feat; it's a vital link for coastal communities and a testament to human resilience in the face of natural disasters. Its construction in the 1960s revolutionized travel, connecting Virginia's Eastern Shore with the mainland. Despite the initial challenges, it has become an integral part of the region's identity and a symbol of engineering innovation.
Akashi-Kaikyō, or Pearl Bridge, is the world's longest suspension bridge. It links the city of Kobe on the Japanese, island of Honshu, to Iwaya on Awaji Island. At almost a mile and a quarter in length, it's impressive not only for its size, but also because it was built in an active earthquake zone that occasionally experiences extreme weather. In fact, earthquake activity meant that the engineers had to alter the bridge's design mid-construction because the foundation shifted! Fortunately, anti-seismic construction methods meant that the Great Hanshin Earthquake in 1995 didn't do substantial damage, so construction was able to continue.
In order to stand up under the difficult weather and tectonic conditions, this bridge was designed with a special stiffening girder system with two hinges. This allows it to handle winds over 175 miles per hour, and earthquakes up to an 8.5 on the Richter scale.
The Akashi-Kaikyō Bridge stands as a testament to Japan's dedication to technological advancement and disaster resilience. Its construction was a response to the Great Hanshin Earthquake of 1995, underscoring Japan's commitment to infrastructure preparedness against seismic events. The bridge also symbolizes unity, connecting Honshu and Awaji Island after the devastating earthquake disrupted transportation links.
This bridge is notable for combining art and science. To look at it, its gently undulating form really does resemble waves. This one isn't for cars—it's a pedestrian and cycling bridge meant to connect three different parks. Its unique shape makes it an attractive, artistic part of the landscape, and it offers users a unique view of the lush parkland around them.
In addition to being beautiful, this bridge is also very high—roughly 118 feet above the ground. Combining artful design and stability isn't easy, and this bridge relied on some computer-aided simulation to get everything just right. It incorporates some very complicated mathematical concepts, and was created using arched steel support structures covered with many Balau wood ribs, which are illuminated at night to make the whole bridge seem to glow softly.
Beyond its architectural beauty, the Henderson Waves Bridge in Singapore is a cultural landmark that integrates art and infrastructure seamlessly. Its unique design, resembling undulating waves, reflects Singapore's commitment to urban aesthetics and creating spaces that harmonize with nature. As a pedestrian bridge connecting parks, it fosters community engagement and offers a serene experience in the bustling city.
The Gateshead Millennium Bridge, in Gateshead, England, is truly one-of-a-kind. It has the distinction of being the world's only tilting bridge, which allows pedestrians and cyclists to pass over normally, then moves to let boats pass beneath.
This is achieved using two steel arches. One holds the deck that allows cycling and foot traffic, while the other provides support above. These two pieces are joined by 18 suspension cables, and attach to the banks of the River Tyne with six hydraulic rams. These allow the bridge to tilt a full 40° in a process that takes about four minutes. Interestingly, this tilting also serves to keep the bridge clean—at it tilts, any trash left on the surface falls toward special traps built at either end.
The Gateshead Millennium Bridge is a symbol of innovation and contemporary design. Its innovative tilting mechanism represents the fusion of engineering functionality and public artistry. As an emblem of Gateshead's urban regeneration, it has become an iconic structure, attracting tourists and locals alike.
This bridge, which connects the Chinese cities of Shanghai and Ningbo, is a whopping almost 22 miles long. It's the longest transoceanic bridge in the world, and required the help of about 600 different experts to design.
Like Akashi-Kaikyō, the Hangzhou Bay Bridge is located in an area that experiences difficult weather conditions, tidal forces, and tectonic activity. It was built using steel piles to prevent corrosion by salt water, as well as cable stayed bridge techniques to help it handle the tides. During its construction, two enormous cranes transported building materials from land to the areas where they were needed.
The Hangzhou Bay Bridge in China is more than a transoceanic link; it's a testament to China's infrastructural prowess and economic development. Connecting major cities like Shanghai and Ningbo, it has catalyzed regional growth and facilitated economic activities, furthering China's position as a global economic powerhouse.
Looking ahead, these bridges continue to inspire future innovations in engineering and design. Advancements in materials, sustainability, and smart infrastructure could shape the next generation of bridges that redefine connectivity, resilience, and environmental impact.
Moreover, these architectural wonders serve as beacons of inspiration for aspiring engineers and designers worldwide, encouraging innovative thinking and pushing the boundaries of what's achievable in structural design.
The legacy of these bridges extends beyond their physical structures; they embody human ingenuity, resilience, and the spirit of progress, leaving a lasting impact on the communities they serve and the engineering landscape as a whole.
Building a sturdy bridge is difficult at the best of times. When you take things like boat traffic, tidal forces, long distances, and earthquakes into account, it's amazing that any ever get built at all. These bridges manage to not only be astonishing feats of engineering, many of them are also aesthetically pleasing, artistic contributions to the landscape around them.
