...10/24/14 Tacoma Narrow Bridge Executive Summary The Tacoma Narrows Bridge was built in 1940 at the cost of $6.4 million funded mostly by the federal government’s Public Works Administration. The purpose of the brigde was to connect Seattle and Tacoma with the Puget Sound Navy at Bremerton, Washington. It was said to be the third largest of its kind. Though it was a long bridge, it was very narrow because it only had one way traffic from each direction. It had a center span of 2800 feet and a 1000 foot approaches on each side. The bridge took nineteen months to be constructed and fell apart barely four months after its inauguration. It is however important to note that even before the inauguration, the bridge had started showing signs of incompetence and exhibiting strange characteristics which shouldn’t have gone unnoticed. The bridge started galloping and swaying and hence got the nick name, the “Galloping Gertile”. In order to under the dynamics of suspension bridges, we need to understand the physics of bridges as propagated by Newton also known as Newton’s Laws. All bridges are subject to Newton's three laws of motion. Newton's First Law states that an object at rest will stay at rest unless acted upon by an Unequal force. For a bridge, this means that unless all of the forces on a bridge remain balanced, one or more components of the bridge will move. Left uncorrected, this instability can lead to a partial or total collapse of the bridge. Newton's Second Law...
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...The BB was the first bridge of its kind ever to be built in the early 19th century. It has braved many elements and has stood the test of time and humanity. It is the first suspension bridge to use galvanized steel as cable wires and trusses. The suspension system was originally designed in iron, but later replaced due to irons dead load weight. The four cables are each nearly 16 inches in diameter and each contains over 5,000 galvanized steel, oil-coated wires. Also the first a dangerous underwater device called Caisson (Inside the caissons, air pressure was used to keep water out of the boxed structure used by workers to excavate the river bottom. Men used shovels, picks, and later blasting to dig out the sand and rocks below and the caissons gradually descended towards the river bottom). After they had been lowered 20 meters, they had to dig/blast their way another 30 meters to find a base strong enough to carry the weight of the bridge. Granite stones were added to form the towers were 276.5ft. At one point they were taller then all skyscrapers of that time to stand as a monument of the two cities. The diagonal cables that run down from the towers which are called “cable stays” purpose was to stiffen the bridge was later fund unnecessary but they were kept for its architectural beauty contribution. "To guard against vertical and horizontal oscillations and to ensure that degree of stiffness in the flooring which is absolutely necessary to meet the effects of violent...
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...wanted to visit the Golden Gate bridge? I am going to tell you about the Golden Gate bridge and why it was made. The Gate bridge was designed by Joseph Strauss the bridge was built from 1933 to 1937.The function of the bridge is to connect San Francisco to Marin county in California. Joseph Strauss hired Charles A. Ellis to be the head of his staff. Charles was later advanced to vice president. Joseph Strauss had Charles A. Ellis hired Prof.George F. Swain from Harvard University.He also hired the designer of New York`s Manhattan Bridge, Leon S. Moisseiff. Stauss and Moisseiff reviewed the design of the bridge which was originally going to be a Cantilever-suspension hybrid bridge. Moisseiff submitted his review of the design and...
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...Construction of the Bridge The construction of the New Tacoma Bridge, which was supposed to replace the old Tacoma Bridge of 1940 which had collapsed took a very long time. The replacement of the old Bridge was delayed for almost a year due to demand of steel which was created by the World War II and also trouble in arranging insurance which would be used for the new bridge. On 30th April 1947 Governor Mon Wallgren announced that the insurance of the bridge had finally been made and arranged. On August 1947 Washington agreed with the request to build the bridge with the construction price having shifted from .8.5 million to 11.2million. On 15th October 1947, the state established bids for construction of the New Bridge, with John A. Roebling’s sons company which was from San Francisco bidding 31.1 million in present terms to be used to constructing the suspension Cable system and...
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...Truss Bridge As said by Ed Grabianowski, “Although the general physics of bridge-building have been established for thousands of years, every bridge presents complicated factors that must be taken into consideration, such as the geology of the surrounding area, the amount of traffic, weather and construction materials.”. When building a bridge an engineer must consider all possible factors that may affect the bridge. Normal environmental factors such as changes temperature, precipitation, and winds must be taken under consideration. Along with environmental factors that are beyond normal weather conditions, factors such as sudden gusts of wind and earthquakes. Environmental factors also known as environmental loads are loads induced by external...
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...Pratt Truss Bridge Research Paper The Pratt Truss bridge was a very unique bridge. This particular truss bridge happens to have been an all wooden truss bridge when it was first built in 1844. This truss bridge has very unique features. This truss bridge is very popular and was yet the most important truss bridge because of it's amazing transformation. This bridge is up to hundreds of feet off the ground. The Pratt Truss Bridge was made was by Thomas and Caleb Pratt in 1844. It was a popular railway truss bridge because it had very long spans. It became popular for railway bridges because it was able to have long spans. The Pratt Truss Bridge Environmental factors have affected this specific tremendously. This Pratt truss bridge was all wooden until the Environmental area of this bridge weakened it. So, this bridge has to go from being all wooden to all copper to make. It's always windy and rains and that's what made the wood break down. Since the break down many workers improved it by changing it to all copper metal. The conditions were mainly natural disasters. The natural disasters included rainstorms and tornados. So therefore this bridge has been through a lot because of the change of all wood to all metal. The Pratt Pennsylvania Truss Bridge was made by Caleb and Thomas...
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...The collapse of the Tacoma Narrow Bridge was a disaster back in the 1940 that is still known to many today. Many physicists have attributed the collapse of the bridge to forced resonance of the mechanical oscillator – where the wind has provided a source of periodic frequency that has tallied the natural frequency of the bridge. (Scanlan, 1990) In fact, there were multiple arguments that have led physicists to conclude that the tragedy was a result of resonance. Although this reasoning has existed for the past few decades and was agreed by physicists, many engineers have found out that such argument was mischaracterised. One of the reasons was that the frequency of the bridge (under 42 mph wind) was 1Hz, which was not close to the actual frequency (0.2Hz) observed during the tragedy. The Van Karman Vortex Street would not be able to result in resonant behaviour on the day of the collapse. There are many more arguments that were supported by different physicists and in this paper, these explanations will be highlighted and evaluated. Some physicists have come up with an argument that attributed such tragedy to...
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...Analyse * Suspension bridge – they are likely to be used to span a wide expanse of water I find it appropriate for it to be built in this scenario because it is not possible to build a beam bridge * Cable stayed bridge- this is a versatile bridge because it can be suitable for short and long spans 1. The community of drakensburg has been struggling with a problem of primary kids and residencies having trouble to cross to the other side of the river to go to school therefore the municipality has issued a tender for companies to pitch. Research The department of transport has dumped large quantity of stones that can be used for the concrete. The stones will help to make the bridge stronger and it will therefore cost the company less money as it will not be required to buy stones Experiement What ive experiemented is that the river has a large quantity of water hich means that we will have three options to choose from in terms of bridges as ive already mentioned them above Modelling Research Designe brief I am going to design a bridge that can accommodate a large number of people meaning that it is going to be strong but it will cost less therefore it will save us money but Is going to be strong. As ive said before that the department of transport dropped a huge quantity of stones in the river the stones will help us when we doing the concrete that is why the bridge is going to cost less because the stones are not man made the are natural mountains stones...
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...Engineering Disaster: Tacoma Washington Bridge Disaster The Tacoma Washington bridge disaster was built in Washington during the 1930s and open to traffic on July 1, 1990. It has spanned the Puget Sound from gig harbor to Tacoma, which is 40 miles south of Seattle. The main font of the bridge near Tacoma, Washington was 28000 ft. long, 39 ft. wide and the steel stiffening girders were 8 ft. tall. The bridge was open for traffic on July 1, 1940. In four months of active life of the bridge before failure, many transverse modes of vibration were observed before November 7, 1940. The crucial event at 10:00am which directly led to the catastrophic torsional vibration was apparently the loosening in its collar of the north cable by which the roadway...
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...Engineering Disaster: Tacoma Washington Bridge Disaster The Tacoma Washington Bridge was built in Washington state during the 1930’s. The bridge was made available to traffic on July 1, 1990. The bridge spanned the Puget Sound from Gig Harbor to Tacoma, which is 40 miles south of Seattle. The main font of the bridge on the Tacoma, Washington side was 28,000 feet long, 39 feet wide and the steel stiffening girders were 8 feet tall. There were four months of active life on the bridge before the failure. Many transverse modes of vibration were observed prior to November 7, 1940. The crucial event occurred at 10:00am. This directly led to the catastrophic torsional vibration which apparently caused a loosening in its collar of the north cable by which the...
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...To Brooklyn Bridge" is the opening section of Hart Crane's most famous poem, The Bridge. Crane's masterpiece is one of the most beautiful and influential American literary works of the first half of the 20th century. It is a poem that defies easy description, at once mystical, romantic, bewildering, witty, secretive, and soaring. That's a lot of adjectives, but as you'll soon see, Crane loves adjectives. Crane labels "To Brooklyn Bridge" a prelude, or "Proem," that will introduce the themes of The Bridge. And if we had to slap a big ol' English AP-test theme word on the whole poem, it would be "Unity," or even, "Mystic Unity." With the whole "Unity" idea, Crane is taking a cue from Walt Whitman, the great 19th-century American poet whose "Crossing Brooklyn Ferry" was a direct influence on The Bridge. For Crane, as for Whitman, Brooklyn Bridge is a symbol of a manmade structure that can join together the fractured parts of society. The Brooklyn Bridge was finished in 1883. At that time, it was the longest suspension bridge in the world, an architectural and engineering marvel. For Crane, the bridge provides a symbol for the possibility of redeeming the modern world from the chains of money and commerce. Published in 1930, The Bridge was panned by many for being too darned difficult and wordy. We'll say it straight up: this poem, like much of Crane's work, is incredibly difficult in the sense of, "What the heck is this guy even talking about?" But the payoff is worth it, because...
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...#2 Churchville Road Bridge The Churchville Road Bridge is a Warren Pony truss bridge that is located in Brampton, Ontario. This bridge is a Warren truss bridge because it has equilateral triangles which spreads out the loads on the bridge. It was first constructed in 1911 then again in 1999 to stay stable for cars. It is used for transporting people across the Credit River which flows near Orangeville into Lake Ontario. The bridge cost about 2,400 dollars and its materials are prestressed concrete, bolts, lattice railings, steel mills, etc. This bridge took a little over a year to build and is still standing after 16 years. Its as long as 90 feet with a width of 30 feet and about 9 feet tall. Churchville also has 3 main parts that includes a super structure, sub structure, and a road bed. Their climate is mostly sunny and partly cloudy as of now. Lastly, this bridge is classified as a truss because it consist of 2 force members that becomes a whole and acts as 1 object. All of these things make the bridge unique in many ways and are why the...
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...Sction1 Elena Jiang The Capilano Suspension Bridge is a simple suspension bridge crossing the Capilano River in the Vancouver. The 137m long, 70m high Capilano Suspension Bridge has thrilled visitors since 1889. While the wobbly bridge and stunning location is a Vancouver landmark, Capilano Suspension Bridge Park offers an all-encompassing BC experience. History, culture and nature are presented in unique and thrilling ways with knowledgeable staff and interpretive signage providing as much, or as little, information as guests want.It is part of a private facility, with an admission fee, and draws over 800,000 visitors a year. The bridge was originally built in 1889 by George Grant Mackay, a Scottish civil engineer and park commissioner for Vancouver. It was originally made of hemp ropes with a deck of cedar planks, and was replaced with a wire cable bridge in 1903. In 1910 Edward Mahon purchased the Capilano Suspension Bridge. "Mac" MacEachran purchased the Bridge from Mahon in 1935 and invited local natives to place their totem poles in the park, adding a native theme. In 1945, he sold the bridge to Henri Aubeneau.The bridge was completely rebuilt in 1956.The park was sold to Nancy Stibbard, the current owner, in 1983. Annual attendance has since increased, and in May 2004, Treetops Adventures was opened. This new attraction consists of seven footbridges suspended between old-growth Douglas Fir trees on the west side of the canyon, forming a walkway up...
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...Research Project: Fred Hartman Bridge The Fred Hartman Bridge is truly a magnificent engineering accomplishment, not to mention a beautiful structure. During the mid 1980s the existing tunnel underneath the Houston Ship Channel in Texas, America, could not cope with the increased volume of road traffic and had to be replaced by a bridge. This large amount of traffic required four lanes with full shoulders in the each direction. A detailed investigation resulted in two independent beams as the most economic solution. The busy ship traffic between the Gulf of Mexico and Houston Harbor required a navigational clearance of 53 m. The towers were protected against ship collision by locating one of them on shore and the other one in shallow water and surrounding it with an artificial island. The project was awarded for $ 91.3 and the bridge was designed in accordance with American Association of State Highway and Transportation Officials and international codes. All structural parts were designed in service limit state and ultimate limit state. The concrete for the roadway slab was C 50 standard and for the tower C 42, the reinforcement had a yield strength of 420 N/mm2 and the structural steel ultimate strength of 520 N/mm2. The high winds experienced in the area were the primary concern of engineers especially since the Fred Hartman is part of a main route for hurricane evacuations. The aesthetically handsome result, a double-diamond tower configuration, creates “truss-action”...
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...The Great Northern railroad company built the Snowden lift bridge in 1913; it spans the Missouri River between Roosevelt and Richland Counties in Montana. Its designer, John Alexander Low Waddell, based the Snowden bridges design on the South Halsted Street Bridge in Chicago. In its completion, the Snowden Bridge was the longest (1,159 feet) vertical-lift bridge in the world. Its cost then was $465,367, which is equivalent to $10,000,000 today. The War Department wanted a bridge that would allow large steamboats to venture up the Missouri during the month that the water was high enough to allow such ships through that part of the river. A kerosene engine could raise the platform 43 feet in about thirty minutes. And in theory, a hand turned capstan might also be used to lift the bridge. The span was last raised in 1935 and the lift machinery was removed in 1943. In 1925 a plank road was built for one-way vehicular and foot traffic, while the bridge was still being used by the Great Northern Railroad. Although this sounds...
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