001 | Bridges: A Guided Intro

Bridges is the breakout single by New Zealand duo Broods, released in 2013 and peaked at No. 8 on the Billboard Alternative Songs chart… It is also the plural for this article. Sorry, I had to. Welcome to my first article! Bridges are truly an engineering marvel. I recently watched an amazing video about bridges that reignited my appreciation for these incredible structures. While there are various bridge hybrids, I'll introduce the basic types. Followed up with a bridge-focused itinerary for your travels!

Types of Bridges

Each type of bridge is unique and reflects the ingenuity and creativity of engineers across centuries. While there are hybrid and evolving designs, here are the most fundamental designs:

🔛 Beam Bridges

Pro: Simple and cost-effective to construct.

Con: Limited to short spans, not ideal for wide crossings.

Best for: Flat terrains with short spans.

How it works: Horizontal beams are supported at each end by piers or abutments.

⛛ Cantilever Bridges

Pro: Can span medium distances without supporting in the middle. 

Con: Requires large, sturdy anchor points, which can be costly and complex. 

Best for: Wide rivers, deep valleys, or areas where central supports are not feasible. 

How it works: Built using horizontal structures extending from supports, with the ends meeting in the middle, allowing the bridge to span without central piers.

▲ Truss Bridges

Pro: Strong and lightweight, ideal for long spans.

Con: Complex construction can be more time-consuming.

Best for: Locations requiring long spans with stable ground.

How it works: A framework of triangular elements distributes weight efficiently.

⋒ Arch Bridges

Pro: Extremely strong, great for carrying heavy loads.

Con: Requires solid foundations, challenging in unstable terrains.

Best for: Valleys and gorges with stable ground.

How it works: Curved arches transfer weight onto abutments at either end.

➿ Cable-Stayed Bridges

Pro: Aesthetic and capable of spanning large distances.

Con: High construction costs due to complexity.

Best for: River crossings and coastal areas.

How it works: Cables run from towers to the bridge deck, supporting the load directly.

⛓️  Suspension Bridges

Pro: Can span very long distances, ideal for wide bodies of water.

Con: Expensive and requires frequent maintenance.

Best for: Wide river or sea crossings.

How it works: The deck is suspended from vertical cables hanging from larger main cables draped over towers.

⏩  Movable Bridges

Pro: Balances road and marine traffic needs.

Con: Requires regular maintenance and complex operations.

Best for: Urban areas with significant ship traffic.

How it works: Bridge sections can lift, rotate, or swing to allow ships to pass.

🛟  Floating Bridges

Pro: Ideal for deep water where traditional foundations aren’t possible.

Con: Vulnerable to extreme weather conditions.

Best for: Deepwater lakes or coastal regions.

How it works: The bridge is supported by pontoons that float on the water’s surface.

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Itinerary

Now that we're all caught up, I'm here to suggest a fun itinerary based on my favourite bridges. These locations are amazing, and there are many other landmarks you could visit as well. But bridges.. truly transport you to a whole new level of appreciation.

1. Auckland Harbour Bridge, New Zealand (Truss Arch Bridge)

   Let's start our adventure in my city, Auckland! First is the Harbour Bridge; its truss-arch design gracefully connects the city to the North Shore. The bridge’s thoughtful integration into the landscape, combined with its impressive lighting system, makes it a must-see for tourists.

A side note while we are in Auckland; my favourite is the cable-stayed Ormiston Road Bridge. Its elegant design, with cable-stayed towers that touch the ground lightly, creates a stunning visual, especially at sunset.

2.  Mangaweka Cantilever Bridge, New Zealand (Cantilever Bridge) 

Continuing our New Zealand travels, we head down to Manawatū-Whanganui, where the Mangaweka Cantilever Bridge spans the Rangitikei River. This historic structure, built in 1904, showcases the engineering of cantilever bridges, allowing for impressive span lengths without the need for central supports. As bridges tend to do, you are met with a gorgeous view.

3.     Sydney Harbour Bridge, Australia ( Through Arch Bridge) Next, we fly across the Tasman Sea to Sydney to admire the iconic arch of the Harbour Bridge, offering stunning views of the Opera House.

4.     Dhola Sadiya Bridge, India (Beam Bridge)

Travel to India to witness the engineering marvel of the Dhola Sadiya Bridge, the longest bridge (9.15km) over water in India, showcasing the reliability of the beam bridge design across the Brahmaputra River.

5.     Golden Gate Bridge, USA (Suspension Bridge) Continue to San Francisco to witness the magnificent Golden Gate Bridge, constructed in 1937. Named after the entrance from the Pacific Ocean to the San Francisco, this suspension bridge is truly an American icon.

6.     Evergreen Point Floating Bridge, USA (Floating Bridge) Head north to Seattle and experience the Evergreen Point Floating Bridge, the world's longest floating bridge (2.35km) that floats on Lake Washington.

7.     Tower Bridge, England (Movable Bridge) Cross the Atlantic to London and marvel at Tower Bridge, where its movable bascule design has stood the test of time, being constructed in 1894.

8.     Millau Viaduct, France (Cable-Stayed Bridge) Conclude your journey in France with the Millau Viaduct, a cable-stayed bridge above the Tarn River Valley, embodying modern engineering excellence.

Conclusion

Thank you for reading! I hope you enjoyed this little journey. Keep an eye out for the next bridge you see or pass, as it may appear more complex than you realise. Be sure to let me know about the bridges you see!

This article was inspired by the YouTube video "Every Kind of Bridge Explained in 15 Minutes" was created by Practical Engineering, and offers an insightful overview of various bridge types and their engineering principles. You can watch the full video here.