SUSPENSION BRIDGE ENGINEERING
Looking at one of the World’s Most Powerful Bridges Today
Bridges have been around for centuries, and were able to assist people in moving from one area to another, and crossing hazards that impeded in the migration and movement of man, successfully and easily. The earliest bridges, were also of course the simplest of bridges, and the earliest being a beam bridge, which could be as simple as placing a plank across a small stream of water. As time passed, and our knowledge on construction grew, more complex, and stronger bridges had been invented such as the suspension bridge, which could span around a few thousand feet to about 2 miles maximum in length, proving to be one of the greatest bridge engineering
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All the towers are built using piers located deep inside the water body, and hold up the entire structure as well as the weight of the cables. The cables that rest atop the towers of the bridges are able to withstand the tension, or pulling force, between them, in order to hold the entire bridge up. The cables that withstand the tension, are known as main cables, and each suspension bridge will have at minimum 2 main cables. Now when you look at suspension bridge, there are large cables that run from end to end, but also smaller cables that run vertically connecting the roadway to large main cables, these smaller cables are known as suspender cables. Suspender cables are used to hold up the roadway, so that vehicles can move across the bridge, and cross the deep waters or canyons, and …show more content…
The towers holding up the cables go through compression or the crushing force. Compression acts on the towers due to the cables that are sitting on top of them. The towers must support these heavy cables in order to keep the roadway up. Aside from the towers, the loads faced on the cables are tension, the pulling force. The pulling force is due to the way the cables are anchored to the land, and the way the suspender cables are anchored to the main cables and the roadway. Due to the different types of connections there are between all the cables, they experience a lot of tension. These are the two major loads which act on a suspension bridge and for a more visual representation of the loads, a diagram is shown below.
Examples of Suspension Bridges Famous suspension bridges include, the Brooklyn Bridge, and the Golden Gate Bridge. Both bridges are beautiful designs of the suspension, and really exemplify the qualities of
71,300 tons of structural steel, 931,000 tons of concrete 42,000 miles of cable wire weighting 11,840 tons, 4,851,700 steel rivets and 1,016,600 steel bolts were all used in the building of the Mackinac Bridge. 1,024,500 tons in total weight is what all this ends up weighting to (Mackinac Bridge 3) (Mackinac Bridge 8). The Main Mackinac Bridge towers reach 554 ft above water and 210 ft beneath the surface to bedrock (Mackinac Bridge 8). To contain temperature changes, high winds and changes of weight on the Mackinac bridge, the deck can move left or right as much as 35 ft at center span. (Mackinac Bridge 9). The total Building time of the bridge was 48 months/ 4
“It was designed with a twenty-two foot roadway and one five-foot sidewalk” (Silver). The silver bridge is a very long bridge. “An eye-bar is a long steel plate having large circular ends with an "eye" or hole through which a pin is used to connect to other eyebars (to make a chain) or to other parts of the bridge.” according to Richard Fields. The whole bridge was built using the eye-bar suspension.
The cables are supported by four steel towers, one at each corner of the grid.
This bridge was necessary to the people of Harpswell due to the weather changes making it impossible for the fishermen and their families to cross from island to island. They used their fishing boats when the weather cooperated, but when storms arose and when the water
At the time of its construction in 1929, the Ambassador Bridge was the largest spanned suspension bridge at 564 meters until the George Washington Bridge was built. It was an engineering masterpiece at the time. The total bridge length is 2,286 meters and rises to 118 meters above the river. Suspension cables support the main span of the Ambassador Bridge and the main pillars under the bridge are supported by steel in a cantilever truss structure. In total, the McClintic-Marshall masterpiece is comprised of 21,000 tons of steel. The immense socio-economical impact that the Ambassador Bridge has on transportation and trade is imperative for daily interaction between the Un...
The area of where the bridge was to cross the Ohio River was said to be one of the hardest places to build but came with some advantages. The section of the river had a solid rock base for the supporting pier to be built on. Since the engineers knew they could build a pier that would not settle they decided on a continuous bridge design. This design type distributes the weight so the steel trusses could be smaller and riveted together. This alone saved an estimates twenty percent of steel that was originally thought to be need to make the bridge cutting down the cost. The two continuous trusses span a collective 1,550 feet across the water. With addition of the north and south approach viaducts, for trains to go under the bridge, the superstructure’s total length is 3,463 feet. The bridge was made to hold two sets of tracks making the width 38 feet and 9 inches. The design called for 27,000 cubic yards of concrete and 13,200 tons of steel with some members being four foot square beams that span a distance of seventy feet. The design was the first step in a long process that would take several years to
According to Suspension bridges: Concepts and various innovative techniques of structural evaluation, “During the past 200 years, suspension bridges have been at the forefront in all aspects of structural engineering” (“Suspension”). This statement shows that suspension bridges have been used for over 200 years, and that people are still using them today because they are structurally better bridges. This paper shows four arguments on the advantages of suspension bridges, and why you should use one when building a bridge. When deciding on building a suspension bridge, it has many advantages such as; its lightness, ability to span over a long distance, easy construction, cost effective, easy to maintain, less risk
Golden Gate Bridge held the title as one of the longest bridges for a reason. It has a total length of 2,737 meters with a width of 27 meters. It also has a clearance of 67 meters for ships to pass by. Besides its incredible dimension, its architecture also plays a tremendous role for its beauty. The bridge employs art deco style, a chevron or beveled shape, used to add visual effect. The concrete structures at the ends of the bridge have chevron form as well as the concrete at the base of the towers. There are two shafts in each tower, 90 feet apart decreasing in width as they go up. The two shafts are connected by cross bracing and having four horizontal struts above. The bridge’s art deco design and towers were designed by architect Irving F. Morrow.
This all iron design made the bridge a lot heavier than it was designed for, which added more stress to the truss. This fact, by itself, wouldn’t cause any alarm. However, the bridge itself, was very poorly constructed. The members of the bridge were all different sizes, and they were not connected together properly. Due to the poor construction and eleven years of use, members of the bridge had started to bend due to the stress. Despite bridge engineers inspecting the bridge for eleven years, no one noticed these faults with the bridge. However, the ultimate cause of this collapse, was so tiny, only one of the investigators, after the collapse, noticed it. A tiny air hole was left during the construction of the bridge, “and grew with repeated stress over eleven years” (Escher, 2009). This hole would develop in a crack, due to the changing temperatures and the trains crossing it for over eleven years. This would weaken the overall strength of the bridge. The cold winter air and the weight of the train would ultimately prove to be too much, and the whole bridge came crashing
In 1883 Brooklyn Bridge has opened and it was the longest suspension bridge at that time.It connects Manhattan and Brooklyn by spanning the East river. There is no entry fees for visiting Brooklyn bridge. You can take a bus or train to reach there.
The bridge was designed at a time when America was moving toward streamline products, this included the design of bridges. The Tacoma Narrows Bridge was a sleek, graceful looking suspension bridge. Suspension bridges consist of many cables anchored...
In her essay,”Importance of the Golden Gate Bridge,” Stephanie Stiavetti suggest that “It maintained this point of pride for nearly 25 years until the Verrazano- Narrows Bridge was built in New York in 1964. Today, this historic San Francisco landmark holds its place as the second largest suspension bridge in the country, behind Verrazano Narrows.” Back then, experts thought that it would be impossible to build a bridge across the tides and currents in that area because strong currents and tides would make construction extremely difficult and dangerous. The water is over 500 feet deep in the center of the channel, and along with the area's strong winds and thick fog, the idea of building a bridge there seemed nearly impossible. Despite all of the problems of building a bridge across the Golden Gate, Joseph Strauss was named as lead engineer for the project. Construction began January 5, 1933, and in the end cost more than $35 million to
Truss bridges can be built three different ways—as a pony bridge, through bridge, or deck bridge. A pony bridge, or a bridge in which the bracing is only on the sides and on top of the deck, are most often used when having a lighter load as there
The 1.78 mile western span of the bridge between San Francisco and Yerba Buena Island presented the first obstacle. The bay was up to 100 feet deep in some places and required a new foundation-laying technique. Engineers developed a type of foundation called a pneumatic caisson to support the western section. A series of concrete cylinders were grouped together and then capped-off, having the air pressure of each cylinder identical to balance the beginning of the structure. From there, the workers added sets of new cylinders until the caisson reached the bottom of the bay. Then, in order to reach the bedrock, they inserted long drills down the cylinders, digging until they reached bedrock. After the caisson was balanced at the bottom of the bay, workers filled it with 1 million cubic yards of concrete, more concrete than was used for the construction of the Empire State Building! This caisson connected the two suspension bridges that make up the western part of the bridge.