Essay about Enb110 project report

Bridges have been used for thousands of years, beginning with natural formations, such as huge rock arches (Appendix A). The first bridges made by humans were most likely simple spans of wooden tree trunks laid across streams, or planks, such as rafts tied together (Gascoigne, 2001). These simple designs evolved over time, as new materials became available, to form the hundreds of bridges we use today. Some basic bridge designs include truss, arch, beam and suspension bridges. The most basic of these is the beam bridge (Appendix B1), which consists of a deck, spanning a relatively short distance, that is held up by a pair of abutments (vertical supports at either end). When weight is placed on

T= 40ms, I figured this by guessing cause I could not find any information on how to calculate. So I used the equation for t and plugged in different numbers until I got the 10ms that was already given in the table. t= T x 0/360= 40ms x 90/360= 0.01 x 10^-3= 10ms

Boylestad, Robert L. Introductory Circuit Analysis, VitalSource for DeVry University, 12th Edition. Pearson Learning Solutions, 11/2012. VitalBook file.

First, we take a look at all the years of research and designs that are completed over the years; thus, we have to trust that we are receiving the most up to date research and findings. On January 28, 1979, just 7 years to the date began the start of the structural assembly of the

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

All are very effective and work well if built in the right conditions. The thing that separates these bridges from one another is that they all have different points of compression and tension. Tension is two forces of opposition that pull away from each other to keep it from being pulled together. If you imagine a rope in a game of tug-of-war, the rope has a lot of tension because it is being pulled apart, but the opposing force inside of the rope is trying to keep it together. The same can be applied to a bridge truss because the tension truss is opposing the compression truss by pulling the bridge apart. Tension also pulls the platform of the bridge by stretching it to keep the bridge from collapsing. Compression is two forces in opposition that push an object together to try to compress it. If you think of someone standing on a soda can, the soda can tries to resist being squished, but the weight of the person standing on the can still squashes it. This example can also pertain to the truss on a bridge. A compression truss opposes the tension truss by pulling the bridge together. Compression is also placed on the top of a truss and in its bases. The compression at the top of the bridge counteracts with the tension of the platform and balances out each force. The compression in its bases is from the weight of the platform and trusses. Bridge engineers calculate the tension and

Hecox (2011) says that the arch structure of the Tillman Bridge makes the canyon walls hold the weight of both vehicles and the bridge itself. In addition, the arch structure allows a better vision of the canyon for the drivers, which was a request of the population to the engineers of the project. In the other hand, according to Jones (2015), the truss structure of the new St. Anthony Bridge also was requested by the population because they wanted to keep a truss bridge in that place. The author also affirms that the St. Anthony Bridge is a truss, but the project team proposed adding a posttensioned concrete bottom chord to the steel truss in order to reinforce it. The project team made this choice because one bridge in Minnesota has collapsed in 2007, and the engineers wanted to lessen the fracture-critical issues to avoid a new catastrophe. In addition, this posttensioning approach wiil make the structure redundant for both resiliency and long-term durability. In conclusion, both bridge's structures were right chosen in order to provide safety and beauty in both

In 1989, an earthquake caused the top deck of the bridge to collapse. This has raised concern in recent years in the case of a large scale earthquake. During an inspection in September of 2009, a 1.5 inch crack was found in a structural truss called an eyebar. The system of the truss is meant to distribute report will describe the tensile load from the weight of the bridge over 4 eyebars. One of them being broken, this same load was now distributed between only 3 eyebars. Because these eyebars were not designed to carry extra load, it became crucially important to repair the eyebar as soon as possible. However, because the bridge is so old, its mechanisms were more complex than what would be designed now in the current day. The engineering company C.C. Myers was contracted to do the repair. C.C Myers decided to repair the eyebar by welding a crossbar to the saddles which had been placed on each end of the broken eyebar (Alfrey, 2010). Four tie rods were then bolted to distribute the tensile load (Reid, 2010). This repair was completed in only 70 hours (Carlsen,

When the bridge was tested, at 26 pounds of pressure, it began to buckle. The top support near the middle of the bridge on one side caved in, and as the weight increased, more of the top supports collapsed. At 47.3 pounds of pressure, the bridge snapped in half. By the end of the testing, the bridge had lost all of it’s top supports, two sections of diagonal supports on either side, and a small portion of the roadway.

We choose design #1 because the truss bridge is a bridge whose load bearing superstructure is composed of a truss, a structure of connected elements forming triangular units. The stressed from tension, and compression helps carry heavier masses. We chose the truss bridge, for it is a very rigid structure and it transfers the load from a single point to a much wider area. A truss is an arrangement of structural members that are connected together to form a rigid frame work. Modern trusses are made of structural steel. All bridges have 4 main characteristics: form, span, material, and travel surface in relation to the structure. A truss bridge is one form that a bridge can take and there are at least 30 different kinds of truss

A truss is a complex structure. Each piece needs to fit perfectly to perform its role, and anything less will mean that the truss will be unstable or simply does not hold an applied load. A truss bridge requires detailed construction and knowledge of how it distributes the forces. With the lack of this knowledge your truss could fail to withstand an applied force.

If a bridge isn’t built right, with the correct physics and design, it is not going to be a stable, safe passage. The pillars on the original Sunshine Skyway Bridge weren’t deep enough in the ground, and they were not close enough together. As mentioned previously, this caused cracks in the bridge. The cracks were repaired, and the pillars were installed deeper and actually strengthened the bridge. However, these corrections proved to be inadequate when the Skyway was struck by the freight ship. When looking at old pictures of the Sunshine Skyway Bridge, it is very evident that the gaps between the pillars were too wide. When the ship collided with the bridge, the stress load was too much on the remaining pillars, and the bridge instantly collapsed, with a large piece of the roadway actually left sitting on the very ship that had just hit it. The way the pillars were installed on the Sunshine Skyway Bridge, caused pressure that placed so much torque, or twist, on the concrete pillars. Once the pillars on the bridge started cracking, they bent the I-beam so much that when the tanker hit the beam the bridge collapsed. Fearing for their own safety, due to questions about the stability of the remaining bridge, rescuers were unable to search for survivors underneath the area of the destroyed bridge. 36 people were killed in this tragic

Overall, my team used this structure because it is used for strength and weight distribution, so my team decided to use triangular shapes as the beams in order to take the force acting at one point of the bridge and wide it. This will

Prior of this time, most bridge design were based on trusses, arches, and cantilevers to support heavy freight trains. Automobiles were obviously much lighter. Suspension bridge design had been envolving into producing bridges of maximum grace, lightness and flexibility which actually was more suited for carrying lighter cars and not heavier train. Unfortunately, engineers did not fully understand the response of the suspension bridge design to these poorly understand forces. The second reson was due to the excitation of torsional mode. The Tacoma Narrows Bridge was built with shallow plate girders instead of the deep stiffening trusses of railway bridges, in which trusses allowed wind to pass through but plate girders, on the other hand, present an obstacle to the wind. As a result of its design, it was proved that the bridge was too light and unstable. And causing alloping Gertieaction which were driven by the wind were being experienced by the bridge.

Probability and statistics provide a framework for dealing with such uncertainty. As the methods and concepts of structural reliability developed over the last few decades, they have become increasingly better understood and approved by engineers. At present, reliability can be considered as a rational evaluation criterion for bridge performance. The reliability methods allow for consideration of uncertainties associated with material properties, geometry and dimensions, loads, and environmental conditions, and they can be used for a better estimation of the failure probability [7-10].