The Tacoma Narrows Bridge, was also known as the Galloping Gertie, was one of the most famous

When bridges are poorly constructed, they may fail due to load they carry, collision by derailed trains or even by vehicles that lose control leading to catastrophic incidences. However, if bridges are well-constructed, the chances or injury are greatly minimized in the event of an accident. Discussed in the subsections are the requirements of AS 5100 standards in relation to cable-stayed bridges and include design requirements for bridges, bridge aesthetics, bridge functional requirements, bridge component design requirements and bridge construction

In the small town of Waco, Texas who would have thought it was once well known for the structure of a bridge, the Waco Suspension Bridge to be exact. Up until 1870, the Brazos River was just a simple river that had no special meaning to it. The land around it was empty, occasionally you would find cattlemen pushing their cattle across stream, but that was only because you could not find one bridge that spanned the eight hundred miles of river flowing through Central Texas. This caused a serious transportation issue for merchants and travelers. It became clear that a better means of crossing the river was necessary.

Suspension bridges usually experience torsional forces during very windy conditions where there are high wind speeds, this can create a twisting force causing the deck to rotate resulting in the bridge experiencing shear stress. (Bagga

In the late 19th century, the transportation demands of Quebec and other provinces success in transportation like Montreal’s success in railways led to proposals for bridging the St. Lawrence River. Quebec Bridge has a long story behind it, a bridge that was proposed first back in 1852 but it was not complete until 1919. It collapsed two times in this duration once in 1907 killing 75 workers and second time in 1916 killing 13 workers. In this report I will emphasize on the first collapse.

Sometimes the wind would not be perpendicular, in which the oscillation of the bridge was less, but there was still some oscillation. On November 7th, 1940, the Tacoma Bridge collapsed because the oscillation of the bridge became extreme. The oscillation of the bridge was caused by a wind speed of 42 mph (HistoryLink.org). After, approximately, an hour of a corkscrew like motion, the bridge collapsed into Puget Sound. This marked a huge turning point in the design of suspension bridges from that point in time to current time.

Calculations were performed to determine the effectiveness of the design of the platform. Allowing for a safety factor of 1.5 times the design weight of 10kg and considering the bridge must not be overdesigned; plans were made for the bridge to fail at 25kg, 2.5 times that of the design weight. According to the calculations, the bridge would hold a load of over 15kg and experience failure at 20kg in the members. These calculations were later disproven in the testing, breaking 8kg earlier than expected, due to unforseen errors. An analysis of the bridge design and calculations has been included at the end of this report.

Furthermore, when the millennium bridge opened within the first weekend around 100,000 people had crossed the bridge. Due to such heavy traffic, this lead to something called resonance. Resonance is when the input vibrations frequency coincides with the natural frequency of the structure itself, causing large deflections to develop. The issue caused the bridge to undergo a swaying movement; hence led to its closure. After extensive research and analysis, it was found that the movement was caused by synchronized pedestrian footfall. To prevent this there were two options taken into account the lateral stiffening and the damping; both were used in order to increase the natural frequency of the structure so it did not match the footfall. In addition structures called fluid-viscous dampers and tuned mass dampers were installed to control both horizontal and vertical movements.

Since the early days, the men try overcome environmental challenges and, in this process, ends up creating amazing masterpieces of engineering. Among this works, the bridges appears as the clearest representatives of how the mankind could adapt to Earth’s contours. If the shape of landscape can’t be changed, the bridges are the solution to link two places and allows the connection of the traffic to improve aspects such as the communication and the trade. Depending to the need, to the sources and to the environment, the bridge can be constructed in a specific configuration. There are five main sorts of bridges configurations. First, there is the simplest bridge, the beam bridge. Second, the arch bridge, one of the oldest kind. There are the truss, composed of set of trellises. Lastly, there are the cable-stayed and

The Pratt truss bridge was originally founded by Caleb and Thomas Pratt in 1844. It is mainly used to carry trains. The biggest advantage of this bridge was its low costs for construction and the materials to construct a truss bridge are minimal. It also use materials that is cheaper and light in weight. We can easily identify a pratt truss by detecting its diagonal members, which (excluding for the very end ones) all slant down and in toward the center of the span. The pratt truss was designed by applying few laws that related to the mechanics of materials concept. The bridge is mainly built using steel girders to support the construction of the structure. The below part of bridge weight is high so, it need an enough support to prevent from

In 1919, a study was begun to see if it would be possible to build a bridge across the Golden Gate. Michael O’Shaughnessy was the San Francisco city engineer. He was in charge of the rebuilding of the city after the devastating 1906 earthquake that destroyed much of the city. O’Shaughnessy knew the need for the city to have bridges. Most said it could not be done and others said it could be done but “it would cost about $100 million to build it” (Barter 23). O’Shaughnessy and Strauss, both wanting the same thing, got together. After the two consulted, they figured the only way to bridge the channel was to use a suspension bridge.

The bridge was constructed of carbon steel, which tends to crack. Many cracks were found throughout the bridge among extensive corrosion. Upon investigation, it was found that the collapse was due to a defective eye-bar that experienced a cleavage fracture in the lower part of its head which was resulted from stress corrosion and corrosion fatigue. [26] Since the eye-bars were not designed to be redundant, failure in one eye-bar would disrupt the continuity of the suspension system. This disruption is what caused the bridge to collapse suddenly. The location of the flaw

Built in 1928, by the American Bridge Company, the eyebar suspension bridge was named for the color of its aluminum paint. The 681.2 meter bridge carried U.S. route 35 over the Ohio River, connecting Point Pleasant, West Virginia and Gallipolis, Ohio. At its time of construction the typical family automobile was the Ford Model T, which weighed 1,500 lbs and the maximum permitted truck gross weight was 20,000 pounds. By the 1960s, the typical car weighed 4,000 lbs and the large truck limit was 60,000 lbs.

During the construction, two half-spans being assembled 50 meters above ground level had a misalignment of 4.5 inches or 114mm in camber. It was suggested by John Holland & Constructions to use a kentledge to weigh down the higher section of bridge. It so happened that they had ten, eight tonne concrete blocks on site. These were placed halfway along the higher span to

It is shaped in a way to transfer weight to the towers and anchors with its tension (O'Connor, 1971, p. 372). Cables are made of high strength wires spirally bound to form a rope (O'Connor, 1971, p. 372). Vertical cable suspenders that are fastened to the main cables hang the actual roadway. Stiffening girders and trusses are along the side of the bridge to distribute concentrated loads and help to keep the motion of the bridge at a minimum (Troitsky, 1994, p115).

Superstructure bears the load that is being passed over the bridge and it transmits the forces caused by the same to substructure. Load received from the decking is transferred on to the substructure by Bearings. They also distribute the load evenly over the substructure material as it may not have sufficient strength to bear the superstructure load directly. Piers and Abutments are the vertical substructures which transfer the load to the earth in the foundation. Wing walls and returns are constructed as the extension of