TYPES OF ARCH BRIDGES

The origins of the use of arches as a structural form in buildings can be traced back to antiquity (Van Beek, 1987). In trying to arrive at a suitable definition for an arch we may look no further than Hooke’s anagram of 1675 which stated ‘Ut pendet continuum flexile, sic stab at continuum rigidum inversum’ – ‘as hangs the flexible line, so but inverted will stand the rigid arch’. This suggests that any given loading to a flexible cable if frozen and inverted will provide a purely compressive structure in equilibrium with the applied load. Clearly, any slight variation in the loading will result in a moment being induced in the arch. It is arriving at appropriate proportions of arch thickness to accommodate the range of eccentricities of the thrust line that is the challenge to the bridge engineer.

Indeed, even in the Middle Ages it was valued that brick work curves carried on basically as gravity structures, for which geometry and extent directed tasteful request and dependability. Compressive quality could be depended upon whilst rigidity proved unable. Based upon experience, numerous exact connections between the range and curve thickness were created and connected effectively to deliver numerous exquisite structures all through Europe. The development of the railroad and waterway frameworks prompted a blast of extension building.

Brickwork curves turned out to be progressively well known. With the development of the Coalbrookdal Bridge (1780) another period of curve scaffold development started. Before the end of the nineteenth century cast iron, fashioned iron lastly steel turned out to be progressively prominent; just to be tested by ferro bond (strengthened cement) when the new century rolled over.

During the nineteenth century analytical technique developed apace. In particular, Castigliano (1879) developed strain energy theorems which could be applied to arches provided they remained elastic. This condition could be satisfied provided the line of thrust lay within the middle third, thus ensuring that no tensile stresses were induced.The requirement to avoid tensile stresses only applied to masonry and cast iron; it did not apply to steel or reinforced concrete as these materials were capable of resisting tensile stresses.

Types of arch bridge

There are many different types and arrangements of arch bridges. A deck arch is one where the bridge deck which includes the structure that directly supports the traffic loads is located above the crown of the arch. The deck arch is also known as a true or perfect arch. A through-arch is one where the bridge deck is located at the spring line of the arch. A half-through arch is where the bridge deck is located at an elevation between a deck arch and a through arch. A further classification refers to the articulation of the arch. A fixed arch implies no rotation possible at the supports, A and B. A fixed arch is indeterminate to the third degree. A three-hinged arch that allows rotation at A, B, and C is statically determinate. A two-hinged arch allows rotation at A and B and is indeterminate to one degree.

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A tied arch and is one where the reactive horizontal forces acting on the arch ribs are supplied by a tension tie at deck level of a through or half-through arch.

 

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The tension tie is usually a steel plate girder or a steel box girder and, depending on its stiffness, is capable of carrying a portion of the live loads. A weak tie girder, however, requires a deep arch rib and a thin arch rib requires a stiff deep tie girder. Since they are dependent on each other, it is possible to optimize the size of each according to the goal established for aesthetics and/or cost.

While most through or half-through arch bridges are constructed with two planes of vertical arch ribs there have been a few constructed with only one rib with the roadways cantilevered on each side of the rib. Hangers usually consist of wire ropes or rolled sections. The hangers are usually vertical but truss like diagonal hangers have also been used. Diagonal hangers result in smaller deflections and a reduction in the bending moments in the arch rib and deck

There have also been arch bridges constructed with the arch ribs tilted so they can be connected at the crown. This is done for aesthetic reasons but it does add to the lateral stiffness of the arch bridge and could result in reduced bracing requirements.

Source:http://freeit.free.fr/Bridge%20Engineering%20HandBook/ch17.pdf

Below the Humber Bay Arch Bridge, Toronto Ontario

Shanghai Metal Corporation supply various steel bridges & steel bridge materials. Check our website if you’re interested other construction materials. You can also send us your inquiry, we have English-speaking that will help you to find the best product for you. Don’t forget to follow us on social media and download an application by scanning brand new designed QR code below.

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The Evolution of Bridge

The bridge is used to provide a way over an obstacle, such as water, valley or road. Its size differs according to its destination, it can be used to cross a river or even from one city to another. In some cases, it may symbolize an important point in your life. According to Freud, a bridge may symbolize any sort of transition in the dreamer’s life, for example, moving to a foreign country, changing from a job to another, etc. In this article, we are going to focus about the physical-real-life bridge. Let us see how bridges have evolved throughout the human history and how ancient bridges show us that structure theory is not the only vital factor in the realization of building construction.

We can divide the evolution of bridge technology into 2 eras :

1. The Arch Era

The Arch Era goes from 2000 BC until the end if the 18th century. Arc bridges were well developed by the  Romans and were for the majority stone arches. The Viaduct in Segovia, for example, is over 2000 years old and is still intact until today.

Roman Viaduct in Segovia

We can also find another example of ancient stone bridge in China. The elegant Zhao Zhou Bridge were built around 600 AD and can still be used until today.

Zhao Zhou Bridge

Another famous ancient bridge still in use today is the Siosepol Bridge in Iran, built during the Safavid Dynasty (around 16th Century).

Siosepol Bridge

These bridges were built before the appearance of structural theory. The ancestors of engineer didn’t use theory to guide their design. The type of  bridge structure they used (still used until today) was intuitive and their construction materials were readily available in nature. Stone arches have a very wonderful structures and  blend very well into the natural landscape.

2. The Contemporary Era

This modern era goes from the 19th Century until today. The construction of bridge changed after the Industrial Revolution in the 19th Century, with the introduction of steel.

One of the most spectacular early bridge is the Firth of Fourth Bridge in London, built during the end of the 19th Century. Some may not be fond of its structures but it has been successfully serving its objective until now.


Firth of Fourth Bridge

Other steel bridges were built around the same time in the United States, such as, the St. Louis Bridge and the Brooklyn Bridge

The improvement of wire technology with steel allowed  long span suspension bridges possible. Research in aerodynamics offered a way to design bridges with wind resistant. Some early examples of this type of bridge are the Golden Gate Bridge and the George Washington Bridge. One of the longest one today is the Akashi Kaikyo Bridge.


Akashi Kaikyo Bridge

Another type of Contemporary Era bridge is the cable-stayed bridge. Attempts were not successful before high strength steel was available. Since 1970, many long cable-stayed bridge were completed around the world, such as The Stromsund Bridge in Sweden and the Normandy Bridge in France. One of the newest is the Stonecutters Bridge in Hong Kong, completed in 2009.


Stonecutters Bridge

As we can see from these examples, the availability of construction materials is a dominant factor in the evolution of bridge (stone, steel,…). Bridges are one of the most important infrastructure program in China. Shanghai Metal Corporation supply various steel bridges & steel bridge materials. Check our website if you’re interested other construction materials. You can also send us your inquiry, we have English-speaking that will help you to find the best product for you. Don’t forget to follow us on social media and download an application by scanning QR code below.

Read this article for a more detailed information about the evolution of bridge technology.

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Pictures from Google image.

Ayu P.//SMC editor

The newest fitness craze – “Bridge yoga” and “Subway yoga”

Yoga is a set of psychical, mental and spiritual exercises and practices that transform your body and mind.  So when people say “yoga” I think of a calm, peaceful place where we meditate and relax. However, the hottest trend is completely different from the way I think.

Yoga on subway 

instragram-yoga-4 (1)The “Big Apple” yoga enthusiasts started to practice yoga all over New York, surprisingly not in gyms or parks but on subway!  You have probably experienced rush mornings, chaos and masses moving to work or school. They don’t care about dirty floor, people staring at them, they just twist, bend, stretch. Some of them with yoga mats lay down to do sun salutation. some just simply practice on seats or around poles.

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Although doing yoga on subway might seem very interesting, not everybody is happy about that. As the result of complaints there have been 240 subway acrobats and yoga enthusiasts arrested in 2014 so far. (source)

Yoga on bridge

Natasha-Maui-yoga-retreats-down-dogWhat is the right place for practicing yoga? A bridge!In Dallas, Texas, they started to make yoga classes on the steel bridge with view over the city. You can benefit your spiritual and physical wellness and yet be at the spectacular place. So steel bridges can also serve us as a place for doing sports and having fun.

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Let’s also have a look on Shanghai Metal Corporation’s website with its new projects, steel bridges and metro pedestrian bridges. You can send us inquiry or follow us on Facebook, Instagram, LindkedIn or Twitter. You could also download our new app by scanning QR code. Our English speaking staff will be more than glad to help you and answer your questions

Silvia M.//SMC Editor

You can read more articles by this author here.

Credit and pictures : spryliving.com, sheknows.com, gothamist.com, theyogablog.com, wikipedia.com

The Test of Time

A true testament to the durability and thus desirability of a material is the legacy of the structures and constructions that are left standing as time goes by. We know that the process of galvanization increases the ability of steel to withstand the nature forces of rust and corrosion bought on by water and the elements; let us take a look at the most notable of these structures;

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As with all structures maintenance is required to ensure the safety and longevity of the structure; however few materials, at this cost can boast up to and above thirty years of maintenance free use as is seen with galvanized steel. Pictured above is the Boca Channel Bridge, located in the Florida Keys. It is consistently exposed to the corrosive elements of the sea water, however over its life of 42years it has not required any maintenance due to the galvanization of the steel whereas other, non galvanized bridges in the same area have had to be completely replaced.

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This durability, despite the increased initial capital investment has been shown to save money over time as this maintenance or continual painting is not required, as would be the case with a non-galvanized steel construction. A prime example of this cost is the Goldengate Bridge in San Francisco, California (picture above), where 28 full time painters are required to constantly paint the bridge as its non-galvanized steel bears the brunt of nature and its original rivets are constantly being replaced with new galvanized ones.

Shanghai Metal Corporation offers galvanized steel in a multitude of forms that can be used to satisfy the applications mentioned above. These include piping, galvanized steel coils, strips, sheets, plates, wire, pre-painted steel, roofing material (in a number of profiles) as well as steel grating.

To find out more about these products or to discuss customization and individual requirements please visit our website Here. For more updates on this and other exciting developments follow us on Facebook, Twitter & Linkedin. Or by using your smart device, scan the QR code below!

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Dominick F.//SMC Editor

Sources: Steel Works, American Galvinizers Association, Golden Gate Bridge Org

A Smart Car Jumps Over a Bridge Every Day!

They have filmed some really astonishing car jump stunts in Hollywood. In real life, the jumps such as James Bond: The Man With the Golden Gun, Thelma and Louise and Terminator 2, would result in absolutely catastrophic damage. Still, there is a car that jumps over a bridge every single day.

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In Rotterdam, you can see a Smart Car jumping over an elevated bridge from miles away. The thing that you will see is actually a billboard advertisement made by an advertising agency BBDO Düsseldorf to promote the sales of the Smart BRABUS car. The billboard is attached to the cutting point of the bridge, and when the bridge opens, it seems like the Smart car is jumping over the bridge.

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The BRABUS campaign lead to a phenomenal success of more than 2000 cars sold before its launch. Smart car is famous also for its other creative marketing campaigns. The small size of the car has inspired its marketers to design, say, unique small size parking spaces for only smart cars a way to promote the car’s fuel efficiency (see the picture below). The Rotterdam Bridge campaign is really groundbreaking in automobile industry.

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Shanghai Metal Corporation has successfully implemented some major bridge building projects. Our projects include the pedestrian bridge in Shanghai’s Wuzhou Avenue, an airport highway in Hefei city and an arch bridge in Zhejiang province’s city of Caidong.

To know more about our bridge building projects, please visit our website. Also follow us on Twitter, Facebook and LinkedIn. You can also download our new mobile application by scanning the QR code below.

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Tuomas P. // SMC Editor

Pictures and original stories:  Toxel.com, Adsoftheworld.com, Jalopnik.com