The Tacoma Bridge

The Tacoma Bridge was built in 1940 in the state of Washington. The main point of the construction of the bridge was to connect the city of Tacoma and the Kitsap Peninsula. Once construction was finished, the Tacoma Bridge was the third longest suspension bridge in the world at the time.

There were multiple reasons why this bridge had to be built. The need for a bridge started in the 1880s when the railroads companies proposed to the state of Washington the construction of a bridge to carry railroad traffic. Also around the 1930 the US military needed a bridge to create a direct route between the Puget Sound Naval Shipyard Field and the city Tacoma.

Around that period of time, the country was involved in a great depression and the government was looking for projects to create new jobs and boost the economy. After multiple proposals, the state decided to start the construction of the Tacoma Bridge in 1938.

The Tacoma Bridge at the opening day

On the one hand, engineer Clark Eldridge proposed a design that consisted of a suspension bridge. The roadway deck was supported by deep 25 feet truss girders and the value of the project was $11 million. On the other hand, the well-known and famous engineer at the time Leon Moisseiff submitted a design of a suspension bridge with a total cost of $8 million. The cost of the project dropped $3 million because Leon Moisseiff replaced the 25 feet truss by 8 feet deep plate girders. Due to the change, the suspension cables would absorb more static wind pressure, and the energy created from the absorption of this pressure would be transmitted directly to the towers. The other change made by Leon Moisseiff was making the width of the bridge 39 feet, which made the bridge very narrow compared to its longitude.  

Engineer Leon Moisseiff also made some changes in his original design. These changes would make the Tacoma Bridge the first suspension bridge to use solid beams supporting the roadbed. The problem we see with this design after the bridge was done is that the impact of the wind in the beams caused the bridge to rotate.

With such a narrow design the bridge was easily moved by winds because the bridge wasn’t rigid enough. The new structure of the bridge start showing some problems when the bridge started with small oscillations during the construction process. Engineers involved in the construction of the bridge tried to come up with ideas to improve the design but they didn’t change anything because they thought that the oscillations weren’t going to go any further than that and the bridge was going to be safe. Here is one of the main problems of the collapse. A good engineer would stop the construction of the bridge and try to come up with some remedies to this situration before they keep constructing the bridge. A safe bridge should not rotate and the first thing that a good civil engineer has to have in his/her brain is public safety.

In 1938 the state approved Leon Moisseiff’s project because: it saved money, and had a more elegant slender design. Construction begun in 1938 and the bridge was opened to traffic in 1940 with a total cost of $6.5 million. The bridge collapsed 4 months later. Here is a short video explaining what happened the day of the collapse.

http://www.youtube.com/watch?v=3mclp9QmCGs

After the collapse the Federal Works Agency said that “every new structures involve new problems. We must accept the errors as a price for human progress.” So they didn’t go against Leon Moisseiff or against the supervisor of the project because they said failure is what it takes for human progress.

I might agree with the fact that it takes erros as a price for human progress because we cant do everything right at the first time, but I think that the Federal Works Agency is completely wrong and their statement is completely unethical from the point of view of any code of ethics. The state chose to save money by picking a much more aggressive design that could potentially harm the public because they said that it was innovative. From my point of view, it is the engineer's as well as the state's fault because Leon Moisseiff did not design a safe bridge and the state was only worried about saving money and they did not think about safety.

Hopefully no one died in this collapse but if I was part of the Federal Works Agency I would go against Leon Moisseiff and against the committee who chose his design for forgetting one the main points of the codes of ethics which is to protect public welfare.

Nanotechnology + Civil Engineering = A Bright Future

Nanotechnology is the creation and utilization of functional materials and devices at the nanoscale or macromolecular level. Nanotechnology is not new for us, at least for people that are related to engineering but the new applications of this new technology into Civil Engineering are breaking the barriers of safety.



Nanotubes

First of all I would like to introduce you to nanotechnology so we are all in the same page before starting to talk about its benefits for construction. A more general and broad definition for nanotechnology is the manipulation of matter of an atomic or molecular scale to then apply it to multiple fields. One of the fields that is benefiting from this technology is the medical field since researches think that it could potentially cure cancer.

 

If you do not really know what nanotechnology is all about after reading this small introduction you should check out this video before you keep on reading this article. It compares the scale of the nanomaterials and it also explains basic concepts of nanotechnology. Once of the things that this video does really good is to explain how we can apply a very small atom to build a very big structure like for example a bridge.

http://www.youtube.com/watch?v=TuljCWV6gLU&feature=related
 

I personally have been interested in nanotechnology for a long time. My first contact with it was when I took COMM 110 at North Dakota State University. One of my speeches was about nanotechnology and I had to meet and plan interviews with some of the researchers working at the North Dakota State University Research Park, so I feel very comfortable talking about it.

Years ago when nanotechnology was first discovered, people thought that could only be used to medical or electronic purposes but now researchers are coming up with new nanomaterials that can be applied to structures to make them stronger.

These new applications of nanotechnology in Civil Engineering are mainly focused on three areas: Steel, concrete, and coatings. New advances made in the steel area are ultra-high strength and ductility of steels which as its name describes, make steel able to support more intense internal forces before failure stresses and strains are reached. Other advances made in concrete are the creation of the CNT. The CNT also known as Carbon Nanotubes are reinforced concrete. The Carbon Nanotubes have the avility to improve the performance of the structure over the years.

Here is a great video that explains how to change the properties of concrete by useing nanotechnology. It will not take a lot of you time and it is really interesting!!

http://www.youtube.com/watch?v=JU_iMRT0ifw&feature=related

 

                     

One of the areas I feel we are going to see the most impact of nanotechnology in Civil Engineering are the Coatings. Some of the new materials related to coatings are: new composite materials, photocatalytic coatings, corrosion protection coating and also self-cleaning coatings. Some of the self-clean materials will be able to avoid corrosion or make road signs never need to be washed. Nanotechnology is not only going to make the structure safer and stronger but it also would make it look like new after long periods of time.

Once nanotechnology is fully introduced into civil engineering cracked bridges and pavement will repair on their own, guardrails will re-align automatically and bridges will be able to adjust their shapes to control movement caused by winds. 

                         

If you guys dont feel like you have enough information about nanotechnology in the future in general and not just for civil engineernig purposes here is a video that explains everything you might want to know about it.

http://www.youtube.com/watch?v=L2KpYRCUjmQ

Besides that last video, this was a brief explanation of how much nanotechnology will affect Civil Engineering in the near future and I am sure that by the time I graduate there will more nanomaterials ready to be used. Nanotechnology can’t hurt Civil Engineering, in fact nanotechnology helps to improve the main purpose of Civil Engineering which is public safety. I am personally looking forward to start taking some courses that relate nanotechnology and Civil Engineering like Environmental Nanotechnology or Fundamentals of Nanotechnology so I can apply these technologies in my future designs once I graduate.

The Oresund Bridge

The Oresund Bridge is a “structure” that connects the city of Malmo in Sweden with the city of Copenhagen in Denmark. I would like to refer to the Oresund Bridge as a structure because it is not a bridge neither a tunnel, the Oresund Bridge is both.
 




The Oresund Bridge is tall enough so sea traffic can go through

Sweden and Denmark were physically connected since the beginning of time but around the late 1990s the governments of both countries decided to change the way this countries were connected by building this structure to connect one of most vastly expanding economic areas in Europe.  The project begun in 1991 and it was done in 2000. After nine years of work and over 15 million euros invested in the project a group of civil engineers designed the longest and the most efficient combined road and rail bridge in Europe.

Image of the route of the bridge

The question is, why did they build it like that instead of just building a normal bridge? The engineers that were in charge of designing this project faced multiple problems. There was air traffic due to the Copenhagen Airport and also ship traffic going through the channel between Denmark and Sweden. They could have designed a taller bridge so ships could go underneath it but then it would be impossible for airplanes to land in the airport. So they designed a bridge that turns into a tunnel deep enough so that ships can go through. This design is a very innovative idea that revolutionized the way we see bridges today.

 

Unlike other engineering projects that go bad and end up costing a lot of money to the governments like the Central Artery/Tunnel Project in Boston, the Oresund Bridge didn’t present any problems through the construction process and the results are outstanding. The Oresund Bridge offers a 4-lane road carrying 6 million vehicles per year and more than 60,000 travelers per day, and two train tracks used by another 8 million people each year.

Connection between the bridge and the tunnel

The Oresund Bridge consists of 3,510 m undersea tube tunnel and 270 m entry tunnels at each end. A 4 km long tunnel with two rail tubes and two highway tubes on one level, an approximately 4 km long artificial island, linking the tunnel and the bridge, and a 7.8 km long, two-level bridge with the motorway on the upper level and the railway on the lower level. The entire project used 500,000 tons of concrete.

 

Unlike other structures similar to the Oresund Bridge like the Channel Tunnel that connects France and England (that I personally travelled in), the Oresund Bridge has an outstanding performance. Unlike the Channel Tunnel (the only possible way of transportation is by train), in the Oresund Bridge you have the freedom to decide whether you want to have more independency and travel in your own car rather than just riding the train. Unlike in the Oresund Bridge, I think that traveling in the Channel Bridge is more time consuming because it works just as an airport, you have to get early, and do the check in procedures. I think that the designing of the Oresund Bridge combines perfect the needs of the population because it gives you the freedom to decide how you want to travel.

Here is a link to a video that explaines everything I have talked about in this article. The problems engineers faced, and it also explains facts about the birdge like the way the strucutre was constructed and other interesintg facts.

http://www.youtube.com/watch?v=g71KpjG3Bu0

 

The Oresund Bridge

The Oresund Bridge is not just an engineering miracle but an economic push for the countries involved.  Ever since the project was done, Sweden and Denmark have experienced an economic growth because it opens more opportunities for people to work on different countries within Europe.

I don’t see any problems in the Oresund Bridge. If I have to rate the project I would give it a 10. 10 in design, 10 to the economic growth that generates the bridge itself and 10 to the fact that it has an amazing performance for such an aggressive design. This bridge has drawn a line separating past and future in the way we look at engineering structures. I hope that one day I have a chance to work on a similar project, where I can challenge my knowledge to break the barriers of structural design.

Building Our Future

Anywhere you look, Civil Engineering is involved. Civil Engineering is a type of engineering that involves projects that affect everyone. The projects that civil engineers are related may include: designing of transportation networks (highways, railroads, bridges, and airports), water supply systems, sewage systems, and buildings. Civil Engineering has a direct impact on today’s society. A civil engineer determinates how the environment looks and functions to meet the requirements of society.

On a daily basis a civil engineer’s job involves much more dynamism than other engineering positions. Some jobs require the worker to be sitting on a chair all day long, other are mostly outdoors but they don’t have any office time. Civil engineers balance both aspects perfectly. Civil engineers design the project with a team of engineers, and once the project is done their job consist on visiting the site regularly to ensure that the procedures are being done the right way. 

Civil Engineers at work

Civil Engineering is one of the most complete engineering that exists. Other engineering fields are very focused on one purpose. While mechanical engineers focus in machine design, civil engineers work to ensure public wellbeing and the safety of the population. Think about this for a second, what would be the life expectancy if we didn’t have any sewage or water supply systems? Civil Engineering makes life easier and better. How could we travel without roads or airports?

The Colosseum

                         

Civil Engineering is one of the oldest fields of engineering. This engineering is not new for us, long time before other types of engineering were even discovered, people were already applying their Civil Engineering knowledge. The growth of the population is directly related to the evolution of Civil Engineering. It is known that Civil Engineering was first used by the Egyptians around 4000 and 2000 BC to build the pyramids. Many civilizations in the past used Civil Engineering for survival and growth, some examples are: the roads that were built by the romans let them expand their empire throughout Europe, and also the expansion of the rail roads out west, which made possible the rapid growth of the United States.
 

Civil Engineering is building our future. One of the challenges Civil Engineering faces nowadays is how to make this world safer and healthier. Many civil engineers are working on developing nanomaterials that can be applied to structures. The main purpose of these nanomaterials is to maintain a structure strong for a longer time so there is no need of repairing it after several years. By developing these nanomaterials, governments won’t be spending that much money repairing structures because they will be able to stay healthier for longer periods of time. Civil Engineering is one of the few fields in engineering that tries to improve our quality of life.

Nowadays that we are very worried about pollution, Civil Engineering is developing new ways to incorporate sustainable and environmental friendly structures in the construction process. Green Roofs are a different way to make the building environmental friendly and at the same time making it look good.

Example of a green roof
http://www.greenrooftechnology.com/
Here is a link to a page that explains the technology behing green roofs

Civil Engineering is one of the most complete and old engineering techniques. Throughout its history Civil Engineering has been trying to improve our quality of life. Civil Engineering and evolution walk down the same path to ensure human prosperity.