We contacted Matt Alderson at the very beginning of our season. We contacted him to find out a project idea. He gave us a few ideas from following the Vex IQ project section ideas. He found that the Vex IQ project appeared to be very open-ended. So he give us several ideas based on real-life engineering challenges that he had run into in his career:
He told us that some of these problems already have some form of solution but that there is always room for new ideas and improvements. He asked if we needed any more help and suggestions to get us moving forward. He concluded the email with saying he was interested to see what we came up with. |
We contacted Mr. Doshi because after doing some preliminary research, we still had a few questions. He answered all of our questions in great depth. He also gave us an amazing website to go to for more information. We asked him considerations that architects make before designing an arch bridge. He responded saying that the most important element is what they call the clear span. The most important consideration is the length of the bridge. Another important consideration was the aesthetics of the bridge. Also, the material used and the condition of the ground for the foundation of the bridge was important. Mr. Doshi told us that wind, earthquakes, the weight of vehicle/people using the bridge, and more are forces that act on the bridge. Before talking to him, we were under the impression that arch bridges were the strongest type of bridge, however he told us that there is no type of bridge that is stronger than another, but rather how it is built. Mr. Doshi was very helpful and we were thankful that he was able to help us.
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We contacted Mr. Cowan to inquire about the calculations pertaining to arcs and arch bridges. Some of the questions we asked him are “how to calculate the perimeter of an arc” and “how to calculate the area of an arc”. Also we asked him how to calculate the clear span, width, height, length, apolethem, angle, and radius for circular and non-circular arches. Mr. Cowan also told us how to calculate how strong the bridge would have to be considering the weight of the bridge. In addition, Mr. Cowan also informed us that when building the bridge you need to take the demographics of the area in which the bridge is being built into consideration, like average weight and height, of a person and the population of the area the bridge is being built in. Mr. Cowan was very helpful and we were thankful that he was able to help us.
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We asked Chris Robinson to come in because he is an engineer and is very knowledgeable about bridges. We asked him about how engineers calculate tension, resistance, and compression. He said that we had to break it down into its components. For example, they would calculate the separate beams. He taught us that it is not one calculation for the whole thing. Instead, it is other smaller pieces put together. Mr. Robinson that resistance can be calculated through destructive testing and through calculation as well. He told us that the unit of tension and compression is in pascals. Additionally, kilonewtons/kips is the measurement of force (live loads and dead loads). He also gave us the formula that the radius is the (span^2+4r^2)/8r. We asked if there was any special software that did calculations for bridges. Autodesk’s AutoCAD, he said, is one if the programs that he has used in the past.
Another questions we had was what had to be account for before designing and making a bridge. In his opinion, the most important is the intended purpose. “Is it a walking trail, or a bridge going over a 6 lane highway”, he said. This is very important for the structure of the bridge. Other important things to consider is the population, cost (funding available), loading on the bridge, foundation (under the bridge), materials available, government allowing to put foundation in the water, water way clearance (boats, canoes, etc), wildlife, and more. Other information that we got was that there is a Canadian bridge design code with a factor of safety of about 3 times. Also, there is a mandatory check (every year) for the district the bridge is in (such as the Ministry of Transportation Ontario, the Ministry of Transportation and Infrastructure British Columbia, or the Department of Motor Vehicles (many US States)) to check the safety/stability/integrity of the bridge. |
Ms. Rajlic was a very helpful expert! She gave us a lot of information about the process of making bridges and the various forces that are involved. She also gave us information specific to the bridge that our team was focusing on, the Prince Edward Viaduct. She contacted a Chief Representative Engineer and got drawings of the bridge. She said that the cars drive on the deck and the subway is under that. Ms. Rajlic explained that the structural software included Staad, S-Frame, RM Bridge, and many more. The materials used to construct the Prince Edward Viaduct were concrete at the top and steel for the components holding the bridge up and the bottom. Concrete is harder than steel. Concrete is strong in compression and weak in tension. On the other hand, steel is strong with everything. The parts are connected by bolting or welding.
Although the calculations are very hard, said Ms. Rajlic, she was still able to help us with what is used to calculate forces. For example, the different loads. We learned that there are dead loads, live loads, wind loads, thermal loads, and seismic loads. Dead loads are the weight of the members of the bridge. Live loads are the masses of trucks, trains, and cars. Wind loads are force coming from the wind. Thermal loads are forces of the temperature on the bridge. For example, it will contract if it is cold and expand if it is hot. Seismic loads are natural disasters like earthquakes. We learned that the bridge is a 2-hinged arch. Ms. Rajlic said that this was because it becomes narrow at the bottom. She also said that it is one of the smartest and most economical types of arches. Our team asked her what the unit of stress on a bridge is. She taught us that it is force over area. Force is measured in newtons and area is measured in meters squared. The final unit is in Pascals. In the past they tested the factor of safety by working the stress design. Now however, engineers use the limit stated design. We learned that the members are connected and construction loading is done on site. Finally, we learned that the Chief Representative engineer is responsible for looking over the bridge and the City of Toronto is responsible for reports on the bridge every two years. |
Civil EngineerRay Lennark visited our facility to help us expand our knowledge and understanding of forces and calculations on arch bridges. He showed us the the types of loads, forces, and calculations that act on a bridge. His visit was very beneficial in teaching us how forces act on arch bridges and how the bridge reacts and adapts to accommodate stress and the forces that act on a bridge. Mr. Lennark always made sure that we understood what he was teaching us and that we weren’t interpreting the information he was teaching us incorrectly. Mr. Lennark was a wonderful expert and we were very lucky to speak to such an experienced man.
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