Bridges have a way of captivating us, from ancient stone spans to sweeping modern suspensions.
A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the way underneath.
ORIGIN
While it is impossible to say with complete certainty, the first bridges were most likely natural.
Fallen trees or avalanches would have created access to new areas and possibilities for the early humans and as they spread and expanded across the globe, occasional land-bridges would appear from the oceans and offer even greater opportunities.
With the rise of the three great ancient civilizations (China around the Yellow River, Mesopotamia around the Euphrates and Egypt along the Nile), it became clear that river systems were vital to early communal groups.
Rivers provided convenient irrigation, fishing and fast travel but also, conversely, a barrier to expansion. As humanity began to grow and learn, moulding the natural world to their whim, the first true constructed bridges began to appear.
India Bridges
Wood and vine bridges are common to this day in parts of India and constitute the most basic style of beam bridge.
As natural materials like these do not last over the years, it is difficult to give precise histories but they are generally accepted as the most ancient. Suspension bridges came to follow, with supple materials held between two fixed points, known in China since 206BC.
Roman Bridges
With the rise of the Romans and their industrial developments, bridge building became more of a science.
The advent of Roman cement and the adaptation of Greek mathematics gave birth to great weight-bearing constructions impossible with natural stone. Arch bridges could now hold a weight twice that of themselves, culminating in the famous water-bridges known as aqueducts.
After the fall of the Roman empire and the subsequent Dark age, bridge building (at least in Europe) returned to ancient ways.
Post-Renaissance
After the Renaissance, the next great leap came in new man-made metals. Iron ushered in new cable, cantilever and truss bridge styles but had an unnerving habit of collapsing due to a lack of internal strength.
When steel became common in the late 19th century, modern bridge-building and giant constructions finally became possible, changing our understanding of bridges.
It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross.
There are many different designs of bridges, each serving a particular purpose and applicable to different situations.
Designs of bridges vary depending on factors such as the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, and the material used to make it, and the funds available to build it.
Golden Bridge, Vietnam
Rewarded with many architecture competitions worldwide, the Golden Bridge in Vietnam features a harmonious blend of groundbreaking architecture and spectacular nature.
This architecture has inspired fashion designers to make superb collections thanks to its out-of-the-world structure. Besides, the bridge is a favorite spot for many couples to take their wedding photoshoot.
The image of a huge couple of ancient hands (like the hands of the Mountain God) lifting the bridge as a shining golden silk strip toward the high blue sky with deep green forests below is not inferior to any blockbuster scenes.
Golden Gate Bridge, USA
Golden Gate Bridge, suspension bridge spanning the Golden Gate in California to link San Francisco with Marin county to the north.
Upon its completion in 1937, it was the tallest and longest suspension bridge in the world.
The Golden Gate Bridge came to be recognized as a symbol of the power and progress of the United States, and it set a precedent for suspension-bridge design around the world.
Although other bridges have since surpassed it in size, it remains incomparable in the magnificence of its setting and is said to be the most photographed bridge in the world.
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Bridges are widely considered to be among the most impressive examples of man-made architecture. It should come as no surprise that they are closing the distances that exist between locations by prevailing over a variety of challenges.
In addition, there are a great number of well-known bridges all over the world. These bridges have achieved great significance not only because they facilitate travel, but also because they have evolved into symbols that are instantly recognizable.
We’ll take a quick break for ECONOTES, which is centered on types of bridge structures.
TYPES OF BRIDGE STRUCTURES
Beam Bridges
A beam bridge is one of the simplest types of bridge. A perfect example being a basic log bridge – something you may see while out on a country walk.
The deck area traditionally consists of wood plank or stone slabs (often referred to as a clapper bridge). These are supported either side by two beams running between abutments/piers.
Truss bridges
You will notice an array of different variations of the simple Truss Bridge but they all incorporate triangular sections.
The role of these triangular elements is important because they effectively absorb tension and compression to create a stressed structure able to accommodate dynamic loads.
Cantilever Bridges
The bridge works by using cantilevers which may be simple beams or trusses.
They are made from pre-stressed concrete or structural steel when used to accommodate traffic.
Extremely safe and very secure, the design of cantilever bridges is one which still lives on today.
Arch Bridges
The most common type of arch bridge is a viaduct, a long bridge made up of many arches.
The lateral pressure created by the arch span is transferred into the supporting abutments.
Simple yet so very effective an arch bridge can carry everything from pedestrians to heavy rail.
Tied Arch Bridges
The tied arch bridge is a fascinating design which incorporates an arch structure (usually metal) supported by vertical ties between the arch and the deck.
The tips of the arch structure are connected by a bottom chord. This acts in a similar fashion to the string of a bow.
The best example of this is a bowstring which absorbs pressure, keeping both sides of the bow in contact, until it eventually flattens out.
Suspension Bridges
The structure of a stereotypical suspension bridge looks very simple but the design is extremely effective.
The deck of the suspension bridge is the load-bearing element of the structure.
The suspension cables extend out beyond each side of the bridge and are anchored firmly into the ground.
Cable-Stayed Bridges
A cable stayed bridge is dependent upon towers/pylons which are the load-bearing element of the structure.
Cables are connected from the pylons to the deck below.
One of the main issues with this type of bridge is that the central connection of the cables can place horizontal pressure on the deck.
LET’S SEE MORE:
Royal Gorge Bridge, Colorado, U.S.A.
The Royal Gorge Bridge is a tourist attraction near Cañon City, Colorado within Royal Gorge Bridge and Park, a 360-acre amusement park located along the edge of the Royal Gorge around both ends of the bridge.
The bridge crosses the gorge 955 feet above the Arkansas River and held the record of highest bridge in the world from 1929 until 2001 when it was surpassed by the Duge Bridge in China.
The Royal Gorge Bridge maintained the title of the world’s highest suspension bridge until the Beipan River Guanxing Highway Bridge was completed in 2003, also in China.
The bridge remains the highest bridge in the United States and was among the ten highest bridges in the world until 2012.
Laguna Garzón Bridge, Uruguay
The Laguna Garzón Bridge is a bridge crossing the Laguna Garzón in Uruguay, on the border between the Mal-donado and Rocha departments.
The bridge is famous for its unusual circular shape and was designed by Uruguayan architect Rafael Viñoly.
It is designed in a circular shape to force drivers to slow down, and allows for pedestrian access along the one-way circular route, including crosswalks that allow pedestrian access to either the inner or outer sidewalks of the circle.
Laguna Garzón was previously served by a small 2-vehicle ferry that required daylight and good weather to operate. The bridge replaced the ferry in December 2015, providing a crossing for pedestrians and up to approximately 1,000 vehicles a day.
Construction Of Laguna Garzón Bridge
Construction for the Laguna Garzón Bridge began in September 2014 and ended in December 2015.
It cost $10 million to build, 80 percent of which was provided by Argentine real estate developer, Eduardo Costantini.
To build the bridge, 450 tons of steel, 500 cubic metres of concrete, and 40,000 metres of cables were used.
Helix Bridge, Singapore
The Helix Bridge, officially The Helix, and previously known as the Double Helix Bridge, is a pedestrian bridge linking Marina Centre with Marina South in the Marina Bay area in Singapore.
It was officially opened on April 24, 2010, however, only half was opened due to the construction at the Marina Bay Sands.
The bridge was fully opened on July 18, 2010. It is located beside the Benjamin Sheares Bridge and is accompanied by a vehicular bridge, known as the Bayfront Bridge.
Architecture
The design consortium is an international team comprising Australian architects the Cox Architecture and engineers Arup, and Singapore based Architects 61.
Canopies (made of fritted-glass and perforated steel mesh) are incorporated along parts of the inner spiral to provide shade for pedestrians.
The bridge has four viewing platforms sited at strategic locations which provide views of the Singapore skyline and events taking place within Marina Bay.
At night, the bridge is illuminated by a series of lights that highlight the double-helix structure, thereby creating a special visual experience for the visitors.
Land Transport Authority of Singapore claimed it is a world first in architectural and engineering bridge design.
It won the ‘World’s Best Transport Building’ award at the World Architecture Festival Awards in 2010.
It has also been recognised by the Building and Construction Authority (BCA) at the BCA Design and Engineering Safety Excellence Awards in 2011.
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One interesting factor when looking at different bridge designs is their longevity and the fact they have been around for centuries.
Bridges connect communities of distant places. Bridges bring diversity. Good quality is maintained. Both diversity and quality bring new joy. Raw materials contribute to new inventions. This way one good relation is built with consumer and government.
