Last week, we tested the 3" long bridge. We met the requirements and were able to hold 15 lbs. We estimated it to hold 13 lbs, so we definitely reached our goal. The bridge took a very basic design because we thought it was easier to get a lower cost/weight ratio if we kept it simple. It cost around $211,500 and its ratio was $13,914.47. We thought it was going to twist like our last bridge before it broke, but it kind of suddenly snapped at the gusset plates. This week, we will probably talk about our overall experience with this course and discuss how our bridges have improved. The major accomplishment was that we found that our bridge held more than we expected and it held about the average cost/weight ratio in the class. I don't believe we have any issues going on because we had a fairly successful day.
Thinking back to the first couple of weeks, I think teamwork is the most important thing I learned this quarter. After we learned the basics about bridges independently, we were able to come together as a group to build upon our ideas. We collaborated and found which ideas worked best to get the most efficient bridge. I think this skill is a pretty important skill because pretty much all jobs require some sort of teamwork. I think the least beneficial thing in this class was that we were only limited to knex. I understand that working with real pieces of wood would require a larger budget and probably more time. However, I think I would have enjoyed a better experience working with a hand-made bridge built from scratch rather than something a child can build. I really liked working with the physics analysis because it gave me a better understanding as to what goes on in the bridge. I knew that a lot of the forces were split between all of the trusses but I did not know the precise amount of forces in the individual areas. Using the software was also a beneficial thing to me because it really caught my interest with finding my creativity level to building bridges. If I was just given the Knex and was asked to build a bridge, I would not know where to start, but having the software such as West Point Bridge Designer helped me plan out and test which pattern worked the best. I think the course as a whole was a good idea. DJ and Deepak helped tremendously by answering our questions and guiding us in the right direction.
Tuesday, June 5, 2012
Skip Week 10 Blog Entry
The prior week, we finally tested out our final bridge. Our final bridge was a very simple, basic truss bridge that took advantage of the 7" pieces. Our concept was to build a cheap bridge instead of building an expensive bride that could hold a huge amount of weight. This was because the best bridge was defined as the bridge with the best cost/pound ratio in the course. The final cost was $211,500 and the failure load was 15.2 pounds. When you calculate the cost/pound ratio, this is equal to $13,914.47, which seems to be a pretty decent bridge. We thought that the bridge would twist and break, but this was not a problem. It was actually straight when it broke, and it broke in the middle of the bridge at two different gusset plates. We as a group agreed that it did a good job and we were happy with our results. The coming week, we will probably discuss our bridge and identify what was wrong and how we could have improved it. The major accomplishment this week was that we were able to prove that our bridge is functional and successful in the sense that it has a decent cost/pound ratio. We did not have any issues throughout the course and we functioned well as a team, each contributing to the project.
I think the most important thing I learned throughout this course is teamwork. While working in a group, we did planning, documenting, designing, computer modeling, physical modeling, and analyses as a group. We all contributed to the entire group and worked together as a whole. The skill to be able to work well with others is important for me in the future. I will definitely work with other people in the future, and this skill is very important when this happens. Without this skill, I do not think that things will go well, and everything will collapse. The least beneficial thing about this course was that it might have not been to realistic. I understand that the whole process is realistic and the steps taken are real, but it is not realistic that we are using a children's toy for this project. In the real world, we will not use toys, but professional materials and it will not be nearly as simple as this project we did. The most beneficial thing was that it was a hands-on experience. We were able to actually see how the whole process of a bridge design works, even though it was simplified. This was beneficial for me because my major is a Architectural Engineering and I hope to look for a job where I will actually do things relevant to this project. I think the whole section's operation was very good. Everything went by smoothly and the assistants were very helpful. The only thing that I would suggest is maybe making the project more realistic by using real wood and the workshop instead of just Knex pieces.
I think the most important thing I learned throughout this course is teamwork. While working in a group, we did planning, documenting, designing, computer modeling, physical modeling, and analyses as a group. We all contributed to the entire group and worked together as a whole. The skill to be able to work well with others is important for me in the future. I will definitely work with other people in the future, and this skill is very important when this happens. Without this skill, I do not think that things will go well, and everything will collapse. The least beneficial thing about this course was that it might have not been to realistic. I understand that the whole process is realistic and the steps taken are real, but it is not realistic that we are using a children's toy for this project. In the real world, we will not use toys, but professional materials and it will not be nearly as simple as this project we did. The most beneficial thing was that it was a hands-on experience. We were able to actually see how the whole process of a bridge design works, even though it was simplified. This was beneficial for me because my major is a Architectural Engineering and I hope to look for a job where I will actually do things relevant to this project. I think the whole section's operation was very good. Everything went by smoothly and the assistants were very helpful. The only thing that I would suggest is maybe making the project more realistic by using real wood and the workshop instead of just Knex pieces.
Sunday, June 3, 2012
A4 - Fischer Minami Spahija
A4
1) The objectives of this course are to learn about the construction of bridges, analyze the forces in a bridge, become exposed to West Point Bridge Designer (WPBD) and to work as a team to construct a bridge using Knex. There are three people in a group that work together to reach the objectives. The bridge competition is won by whichever team has the lowest cost to weight-held ratio. In the beginning of the quarter, we set up a blog website that held all of our weekly blog posts and assignments. Throughout the term, we gained knowledge about bridges through the West Point Bridge Designer program, playing around with Knex pieces and doing thorough truss calculations to understand the forces. We learned that it was easier to stick with a cheaper bridge that held a lot of weight for its cost, rather than having an expensive bridge that could hold a greater amount of weight. We also figured out that triangles should be formed within the pattern of trusses in the bridge, which created the most stable bridge.
2) Our first objective was to make a bridge that would support a lot of weight while maintaining affordability. We started off with a simple and standard truss design, thinking that since they are used in the real world, they should be well rounded designs. We wanted to make a bridge that would hold a lot of weight using many pieces, so we added many webs into the bridge to make it stronger. We did not think too much about price and continued to make the bridge stronger by adding more pieces to the weak points of the bridge.
Our design goals changed most after we were told that the bridge must have an opening in the middle 3 inches wide and 2 inches tall. The bridge that we had already designed did not meet this requirement, so we decided to design a completely new bridge. We still kept the simple standard truss design and we built off of this. At this point, we decided to move from a strong bridge with many pieces, to a cheap bridge with a minimum number of pieces. We decided to do this because the objective was to make a bridge with the best cost/weight ratio, and we thought that this would be a good idea. Instead of increasing the weight we could hold, we decreased the cost of the bridge.
The individual designs using WPBD allowed us to find that a standard truss design may be one of the best designs around. This was one of the reasons we decided base our bridge design off of a standard truss bridge. The truss analysis helped us because we were able to locate the weak points in our design and reinforce these points so that the bridge was more difficult to break. We were also able to get rid of the pieces that did little or no work so it was cheaper. The actual individual designs using the Knex pieces helped because we could actually calculate and see which design was bad or good. Using this information, we chose the best bridge design and based our final bridge off of this.
We chose our final design by using trial and error. The group came up with two different designs at the end, so we tested both of them and we saw that the bridge one of us had designed was significantly better in both durability and cost than the other design, so we decided that the final bridge would be built off of that bridge.
After testing our bridge for the first time, we realized that it would twist and break when a lot of weight was put on it so we decided to add trusses on the top plane of the bridge in order to keep it from twisting when load was added to it. We also made the bridge as cheap as possible by replacing pieces with cheaper pieces. By doing so, we were able to keep the price down.
In the first test of our final bridge, our design was able to support a weight of 14.4 pounds. Using this as a reference, we predicted that our final bridge was going to hold around 13 pounds, but the actual bridge ended up supporting a maximum weight of 15.2 pounds which was better than what we expected.
3) The final bridge design was a simple and cheap over truss bridge, with a web on top. Our design was aimed toward a cheap bridge with a small amount of pieces rather than a strong sturdy bridge with many pieces. In order to make the bridge like this, we only have a small web on the top plane of the bridge. We also thought about how to use the 7” pieces. Instead of connecting two short pieces with a gusset, we made the 7” piece go through the hole of Knex pieces so that there were less gusset plates. We designed it in this manner because we wanted to make the bridge have less gussets since the bridge commonly breaks at the joints.
Elevation
Plan
Bill of Materials
The total cost of the bridge was $211,500.
4) The final bridge ended up holding 15.2 lbs. This was about 2 lbs more than we expected. Our bridge collapsed by having a few trusses pop out of their gusset plates, around the center of the bridge. There was a small amount of twisting before it collapsed and we all noticed that the joints were experiencing a lot of stress before it broke by viewing the bent trusses.
5) We predicted it would behave like our first Knex bridge, which went through an extreme amount of twisting before it finally collapsed. However, the final Knex bridge only twisted a little bit before we saw some of the joints were starting to pop out. We think the reasoning behind this is because we swapped out 5 inch trusses along the base for 7 inch trusses. Since there are fewer pieces being used, the bridge has fewer gusset plates to bend at. With that being said, more force is being dissipated along one big truss as opposed to have it divided among many, fewer trusses. This caused our bridge to give a more “sudden” collapse rather than gradually bending at the joints.
6) If we were able to modify our bridge further, we would exchange the 7 inch trusses along the base for shorter trusses and more gusset plates. This would give our bridge the ability to bend rather than putting a lot of stress on fewer, large trusses. We were also thinking about adding another level/deck to increase the height of the bridge. This would move a lot of the force away the center of the bridge and distribute it along the sides.
1) The objectives of this course are to learn about the construction of bridges, analyze the forces in a bridge, become exposed to West Point Bridge Designer (WPBD) and to work as a team to construct a bridge using Knex. There are three people in a group that work together to reach the objectives. The bridge competition is won by whichever team has the lowest cost to weight-held ratio. In the beginning of the quarter, we set up a blog website that held all of our weekly blog posts and assignments. Throughout the term, we gained knowledge about bridges through the West Point Bridge Designer program, playing around with Knex pieces and doing thorough truss calculations to understand the forces. We learned that it was easier to stick with a cheaper bridge that held a lot of weight for its cost, rather than having an expensive bridge that could hold a greater amount of weight. We also figured out that triangles should be formed within the pattern of trusses in the bridge, which created the most stable bridge.
2) Our first objective was to make a bridge that would support a lot of weight while maintaining affordability. We started off with a simple and standard truss design, thinking that since they are used in the real world, they should be well rounded designs. We wanted to make a bridge that would hold a lot of weight using many pieces, so we added many webs into the bridge to make it stronger. We did not think too much about price and continued to make the bridge stronger by adding more pieces to the weak points of the bridge.
Our design goals changed most after we were told that the bridge must have an opening in the middle 3 inches wide and 2 inches tall. The bridge that we had already designed did not meet this requirement, so we decided to design a completely new bridge. We still kept the simple standard truss design and we built off of this. At this point, we decided to move from a strong bridge with many pieces, to a cheap bridge with a minimum number of pieces. We decided to do this because the objective was to make a bridge with the best cost/weight ratio, and we thought that this would be a good idea. Instead of increasing the weight we could hold, we decreased the cost of the bridge.
The individual designs using WPBD allowed us to find that a standard truss design may be one of the best designs around. This was one of the reasons we decided base our bridge design off of a standard truss bridge. The truss analysis helped us because we were able to locate the weak points in our design and reinforce these points so that the bridge was more difficult to break. We were also able to get rid of the pieces that did little or no work so it was cheaper. The actual individual designs using the Knex pieces helped because we could actually calculate and see which design was bad or good. Using this information, we chose the best bridge design and based our final bridge off of this.
We chose our final design by using trial and error. The group came up with two different designs at the end, so we tested both of them and we saw that the bridge one of us had designed was significantly better in both durability and cost than the other design, so we decided that the final bridge would be built off of that bridge.
After testing our bridge for the first time, we realized that it would twist and break when a lot of weight was put on it so we decided to add trusses on the top plane of the bridge in order to keep it from twisting when load was added to it. We also made the bridge as cheap as possible by replacing pieces with cheaper pieces. By doing so, we were able to keep the price down.
In the first test of our final bridge, our design was able to support a weight of 14.4 pounds. Using this as a reference, we predicted that our final bridge was going to hold around 13 pounds, but the actual bridge ended up supporting a maximum weight of 15.2 pounds which was better than what we expected.
3) The final bridge design was a simple and cheap over truss bridge, with a web on top. Our design was aimed toward a cheap bridge with a small amount of pieces rather than a strong sturdy bridge with many pieces. In order to make the bridge like this, we only have a small web on the top plane of the bridge. We also thought about how to use the 7” pieces. Instead of connecting two short pieces with a gusset, we made the 7” piece go through the hole of Knex pieces so that there were less gusset plates. We designed it in this manner because we wanted to make the bridge have less gussets since the bridge commonly breaks at the joints.
Elevation
Plan
Bill of Materials
The total cost of the bridge was $211,500.
4) The final bridge ended up holding 15.2 lbs. This was about 2 lbs more than we expected. Our bridge collapsed by having a few trusses pop out of their gusset plates, around the center of the bridge. There was a small amount of twisting before it collapsed and we all noticed that the joints were experiencing a lot of stress before it broke by viewing the bent trusses.
5) We predicted it would behave like our first Knex bridge, which went through an extreme amount of twisting before it finally collapsed. However, the final Knex bridge only twisted a little bit before we saw some of the joints were starting to pop out. We think the reasoning behind this is because we swapped out 5 inch trusses along the base for 7 inch trusses. Since there are fewer pieces being used, the bridge has fewer gusset plates to bend at. With that being said, more force is being dissipated along one big truss as opposed to have it divided among many, fewer trusses. This caused our bridge to give a more “sudden” collapse rather than gradually bending at the joints.
6) If we were able to modify our bridge further, we would exchange the 7 inch trusses along the base for shorter trusses and more gusset plates. This would give our bridge the ability to bend rather than putting a lot of stress on fewer, large trusses. We were also thinking about adding another level/deck to increase the height of the bridge. This would move a lot of the force away the center of the bridge and distribute it along the sides.
Tuesday, May 29, 2012
Disel - Week 9 Blog Entry
Last week we were able to come up with two different designs for our bridge, but from the testing we all agreed that we should use the bridge Skip designed. It's performance was really good and we worked on some changes to make it cheaper so I think we are ready for the competition. The one I designed seemed good but when tested it would not hold more than 7 pounds. Even that I made some changes still is not as good as the other bridge Skip designed. I think we are going to be one of the teams with a good ratio weight/cost.
I learned a lot from this course. I learned a lot about truss bridges. I learned how and where is necessary to use triangles and where is not. I learned that the center of the bridge should always be the strongest part of the bridge. I also learned a simple way how forces are distributed. I learned how to use WPBD software which helps a lot in calculating the cost of a bridge and distribute the forces. The best thing about this course I think was the fact that we had to make a strong bridge but not forgetting the cost. From that I learned a lot about how construction industry works in real life. The competition with other teams made it really competitive.
I'm really happy with what I learned into this course and I think some of the things I learned here are going to help me majoring as a civil engineer.
I learned a lot from this course. I learned a lot about truss bridges. I learned how and where is necessary to use triangles and where is not. I learned that the center of the bridge should always be the strongest part of the bridge. I also learned a simple way how forces are distributed. I learned how to use WPBD software which helps a lot in calculating the cost of a bridge and distribute the forces. The best thing about this course I think was the fact that we had to make a strong bridge but not forgetting the cost. From that I learned a lot about how construction industry works in real life. The competition with other teams made it really competitive.
I'm really happy with what I learned into this course and I think some of the things I learned here are going to help me majoring as a civil engineer.
Skip Week 9 Blog Entry
The prior week, we designed our final bridge for the next week when we will actually test out the bridge. Instead of building a bridge that could hold a huge amount of weight and cost a lot of money, I decided to build a bridge that could only hold a little bit of weight, but is cheap so that the cost to performance ratio is high. I ended up building a bridge with a basic over truss design with many right triangles. I also used the long seven inch Knex pieces and used less gussets because the weak points were at the gussets on the previous bridges we looked at. I also designed it so The cost is about $100,000 and when we tested it, it held 14.4 pounds. This is pretty good cost performance. Disel in my group designed a bridge that had more webs and smaller trusses, but when we tested it, it only held 7 pounds and it cost a lot more than my bridge design so we decided to go with my design. Disel's bridge broke more easily probably because he had many gussets and connectors which made it easier to break. He also had the sliding gusset plates which is a common place where the bridge ruptures. The coming week, we will test out my bridge design for the final test. We will try to make the bride cheaper and stronger in preparation for the final test to improve the cost performance. The major accomplishment this week was that we were able to design a bridge that will look very close to the final design. The bridge we have right now follows all the restrictions and we are happy with how it performed when we tested it. The only thing to do now is to improve on it. The problem is that I am not sure how to improve on it. I have made the bridge as cheap as possible for the current design, and I do not know if there are parts that I can remove. Otherwise, there are no problems within the team. We all agree with the current bridge design and we are helping each other out giving ideas for the bridge.
I learned that you must consider many things when you are designing a bridge. There are many steps when designing a bridge. One of the most important things that one must consider when designing a bridge is what the client wants the bridge to be. Does he want the sturdiest, strongest bridge possible or a very cheap bridge that is not as strong? Does it have to look interesting and unique with a suave design, because it will be a symbol of a city? In this course, we were required to build a bridge with the best cost performance. We had to balance out how much it can hold, with how much it costs. Another thing that is very important is considering the restrictions. A real bridge will definitely need to span a certain distance, be able to hold at least a certain amount, be durable so it will last for a long time, and there could also be a cost range. There are many restrictions that must be followed. In this course, for example, the final bridge for next week must span 36 inches and must have a hollow inside section 3 inches wide and 2 inches tall. After you have all these things, you can start designing your bridge. When designing bridges, you must also think about how the forces of tension and compression are distributed throughout the bridge. In the course, we used basic laws of physics to see how forces of weight were distributed throughout the members of the bridge. One thing you have to remember when dong these calculations is that this is disregarding many factors such as wind and the weight of the bridge itself. For this reason, we can only use these as a reference. One more thing I learned in designing bridges is that triangles are very strong stable shapes so are good to use in the designs. This is because in a two dimensional plane you cannot change the shape of triangles once you have one unlike rectangles where you can slide a side and make a different shape.
I learned that you must consider many things when you are designing a bridge. There are many steps when designing a bridge. One of the most important things that one must consider when designing a bridge is what the client wants the bridge to be. Does he want the sturdiest, strongest bridge possible or a very cheap bridge that is not as strong? Does it have to look interesting and unique with a suave design, because it will be a symbol of a city? In this course, we were required to build a bridge with the best cost performance. We had to balance out how much it can hold, with how much it costs. Another thing that is very important is considering the restrictions. A real bridge will definitely need to span a certain distance, be able to hold at least a certain amount, be durable so it will last for a long time, and there could also be a cost range. There are many restrictions that must be followed. In this course, for example, the final bridge for next week must span 36 inches and must have a hollow inside section 3 inches wide and 2 inches tall. After you have all these things, you can start designing your bridge. When designing bridges, you must also think about how the forces of tension and compression are distributed throughout the bridge. In the course, we used basic laws of physics to see how forces of weight were distributed throughout the members of the bridge. One thing you have to remember when dong these calculations is that this is disregarding many factors such as wind and the weight of the bridge itself. For this reason, we can only use these as a reference. One more thing I learned in designing bridges is that triangles are very strong stable shapes so are good to use in the designs. This is because in a two dimensional plane you cannot change the shape of triangles once you have one unlike rectangles where you can slide a side and make a different shape.
Jonathan Week 9 Blog Entry
Last week, we were able to make some more finishing touches to our bridges. Disel got to test his version of his bridge, but it didn't turn out as good as he expected. Soichiro got to test his bridge later in the class and it turned to be a lot cheaper that holds more weight. I think it cost around $100k and it held around 15 lbs. The key to making this bridge was that we didn't use any grooved pieces so we can try and make it pretty cheap. We will make more modifications to this bridge and we will probably end up using something similar to what we have now for the final bridge competition. I think the main fault in this bridge is that it follows the same pattern throughout the whole bridge and it is not reinforced in the middle so it might end up breaking down the center. Another problem is that we are unsure of how to improve the design of the bridge, since it held so much weight the first time.
I have learned a great deal about designing bridge from this class. One is that it is a lot easier to try a design out on the computer before you actually build it. This allows you to see basic outcomes as to where some of the pressure is building up on, so you can easily alter the bridge to dissipate the pressure. Another thing I have learned is that there isn't simply one good design that will win the competition. Since the competition relies on the weight/cost ratio, there are many ways to try and win. An example is that you can go for a very heavy bridge that holds a lot of weight, or the opposite, which seems to be more effective. Hand-calculating the pressures on the bridge is possible and is very important if there isn't a computer program that can do it for you as it can take quite a lot of time.
I have learned a great deal about designing bridge from this class. One is that it is a lot easier to try a design out on the computer before you actually build it. This allows you to see basic outcomes as to where some of the pressure is building up on, so you can easily alter the bridge to dissipate the pressure. Another thing I have learned is that there isn't simply one good design that will win the competition. Since the competition relies on the weight/cost ratio, there are many ways to try and win. An example is that you can go for a very heavy bridge that holds a lot of weight, or the opposite, which seems to be more effective. Hand-calculating the pressures on the bridge is possible and is very important if there isn't a computer program that can do it for you as it can take quite a lot of time.
Tuesday, May 22, 2012
Skip Week 8 Blog Entry
The prior week, we started the analysis of the truss bridges. We used laws of physics and conservation of energy to calculate how the force of a load on a bridge is dispersed throughout a truss bridge. By doing so, we were able to calculate the tension and compression on the individual members of a truss bridge. We also made small modifications to the bridge and plan to further improve it. The coming week, my teammates and I agreed to make final modifications to the bridge to get it ready for the final weight load test. The major accomplishment this week was that we we able to learn how to analyze a truss bridge and how forces act on the bridge. Using this knowledge, we can improve our bridge and make it stronger. The major problem is that the bridge seems to be a little weak. My teammates and I have to work on the bridge to make it stronger.
For further analysis, I would like knowledge about the bending of the members. The analysis talks about tension and compression, but I do not know when the members would break. You could have a perfect bridge that holds a great amount of load, because it is strong against tension and compression but I think that bending and breaking is another story. I would also like to learn about twisting. This is another factor that will affect the bridge. If I have all this information, I think I could do a legit analysis of the bridge.
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