WPBD

            At this point in the quarter, all of the students participating in out engineering 103 lab section involving bridge design have been using a specific application provided by the school for the creation of the designs and models.  This application also serves the useful purpose of helping us engineering students learn about judging the different effects and properties of the particular shapes and materials used in a respective design.  Last week we modeled and submitted our own designs, while during class we compared them with our classmates and each group submitted a new one that the students felt represented each group.  As for my teammates, we all agreed we liked the stability of triangles, however more time needs to be dedicated familiarizing ourselves with the different materials and their effects on the design and price, a skill we will all need to acquire.  At least we accomplished to learn about the different factors that apply when designing a bridge.

            To address the question at hand of weather the program currently used for designing a bridge is realistic or not there are more than one factor to the answer this question.  On the one hand, the program is exaggerated with many reactions of the bridge, which can often be considered unrealistic, however it makes sense why they would want the designers of the bridge to understand the risk a t cost and see exactly where they fall wrong with each design.  Additionally, no matter how much designing one does on a computer, it is most probable that nothing truly resembles the real world and its rules   The design matters, very much, nevertheless is not the, only component to a good code and experiment, or work environment for that matter.  Which may or may not affect how realistic this program is seen as, but that depends on the yes that are judging it and their own definition of realistic and unrealistic.

-  Ana M. Franco

West Point Bridge Design

Last week each student in the class submitted their own bridge design to our professor, James Mitchell, online via a survey. In class we compared the results of each bridge side-by-side. My bridge, coming in at close to $590,000, was one of the most expensive. The least expensive bridge had a cost of just below $250,000. I clearly wasn't going to be winning this first competition.

For the rest of that class period, each group was to analyze the bridges each member of the group had created. My group members and I decided that we would benefit the most by attempting to build a bridge entirely from scratch on West Point Bridge Design, keeping one goal in mind: have a cost below $250,000. After about 50 minutes had passed, the least expensive bridge we could design would cost about $440,000. I was happy with this, however, because in about a day I'd learned how to reduce the cost of a bridge by over $100,000.

My group and I decided we would play around on WPBD before our next class together, but our group's bridge had already been submitted and there was no way we could do anything to change our design's official status until the next class. I am very much looking forward to seeing the results of the competition between groups in class tomorrow. I'm sure our bridge is not the least expensive, but maybe it is the safest or the most durable. On another note, the group is not having any trouble working together. So far we haven't run into any issues that we cannot fix by simply looking in a book or asking a question to someone with a good understanding of bridges.

Going back to the WPBD program, I have noticed that some aspects of it are not very realistic, however, the program helps the used understand many important areas of civil engineering. As we discussed in class, when you test a bridge, the program exaggerates the displacement of the bridge's road surface so that the user can easily see how significant the changes are that they make to their bridge.

Without even realizing it, users of WPBD are learning how civil engineers use computers as tools to help them perfect their designs. This program calculates the stress on each member of the bridge and displays it in a chart within a fraction of a second after running the test mode for a bridge design. This saves time for the civil engineer and allows them to make more changes to their designs without having to go through the process of manually calculating all the forces acting on each member of each bridge design.

Personally, my favorite part of WPBD is that it calculates the cost of my bridge for me. Every time I change the size, material, or structure of a member, the cost automatically updates. This makes it easy to avoid heading in the wrong direction with a design and ends up saving alot of time. The program provides standard options for bridge materials and dimensions which helps users learn which materials are the best for designing bridges.

Overall, the program is unrealistic in the sense that it does not account for certain forces which act on bridges. Wind is something that can significantly affect a bridge in reality, but the program does not provide for such a force. All of the things that program does do accurately definitely help the user speed up the process of designing a bridge.

The Reality of West Point Bridge Design

West Point Bridge Designer is a great program to start designing bridges with.  It helps you to understand how to design structures, provides an idea of the engineering design process, how to improve the effectiveness of bridge designs, and provides a tool to help us figure out how structures work.  Although all of this is great, WPBD is not entirely realistic.  WPBD focuses more on the design process than the structural design of the bridge.  Although it will tell you if the design is stable for a specific computer coding, that does not mean it will work in real life situations. 

                In a real life situation, many different kinds of materials, connectors, and members are used.  West Point Bridge Design offers some variations, but not as many as engineers consider when designing a real bridge.  Engineers also have to consider roadways, weather conditions, the body of water the bridge is going over, and a three dimensional structure.  WPBD allows you to make some changes to the roadway, but not enough to get a real sense of the design.  Along with environmental concerns, bridges undergo a lot of fatigue and engineers must figure out what kind of material to use to make the bridge last as long as possible while still being efficient. WPBD does not consider this, making the user unaware of the efficiency of their bridge.  The user would also be unaware of how much weight their designed bridge could hold.  In actual bridge designing, many different forms of vehicular traffic have to be taken into account, along with the self-weight of the bridge and environmental conditions, such as snow or an earthquake.  West Point Bridge Design accounts for some failures that occur from the design, but not all that could occur on a real bridge.  Engineers must take these added failures into account, including deflections that occur from driving on the bridge or weather.  West Point Bridge Design fails to do this completely.

                Although West Point Bridge Design does not accurately represent a realistic bridge, it is a very good learning tool for students.  It focuses on the fundamentals of building and using trusses, and gives a good representation of how a bridge would act if weather, vehicular loading, and the river were not factors of the design. 

                In week 3 of lab we reviewed the results of our A1 designs and then each team developed an improved design in class. Our team’s design was improved from any of our individual designs, but did not come close to competing to the most cost efficient. Unfortunately, the lowest we could make it in the time allowed was around $41,000.  We were happy with our design but I personally wished we had more time to work on it to see how cheap we could make it. 

                For this week in lab, I hope to gain a better understanding of how a bridge holds weight as we will be using Knex for the first time.  I know we will have to document how much weight it holds and I would really like to be on my game the first time around.  I hope to accomplish an efficient design that my team will like.