week 4

Since we have been experimenting with West Point Bridge designer, we have noticed many helpful options.  Some ways to make the strongest and most cost effective bridge would be to use hollow tubes and to change each of their size.  These variables now restrict us less and allow us to be more creative in our designs.  I also enjoy the fact that this program also allows us to pick each weak member and make appropriate modifications to it.  There are some drawbacks.  For example, this program shows a truck moving across so the force is felt in different areas of the design.  This conflicts with future designs for our Kinex design will have a fixed load in the middle.

Week Four - Greenwood

Week three was both a very productive and very informative lab.  The main focus of the lecture and the rest of the class was the cost efficiency of our bridges.  It was made clear to us (through COMP1) that we could not get a contract without proposing a cheap and effective way to create a bridge.  Therefore, our group sat down to begin discussing how we would go about slicing the cost of our bridge design.  Originally, our pricing was somewhere around $350,000.  We considered this to be outrageous, and proceeded to test out different materials and designs.  Eventually, we came up with a successful design which brought our pricing to around $215,000.  We are not yet finished though, and over the next couple weeks we will implement what we have learned into creating the best design we can.

Throughout this module so far, we have been using West Point Bridge Designer, an engineering simulator program which uses an easy interface to let the user first build a bridge and then test it.  The test itself allows a truck to try and drive over the created bridge.  It lets you know where the most tension is in the bridge, or if the truck even feels safe enough to cross it at all.  This tool has been extremely useful for our team, in that we have been able to send our designs back and forth to each other even outside of lab for examination and critique.  It is even a great tool for presenting what I have learned so far.  For example, today in English class I was talking to another student about my bridge design and my professor asked me to stand up and talk about the project.  He was not being sarcastic, but he was truly interested.  I proceeded to show the class my design and its animation, as well as discussing what I have learned so far in the module.  WPBD has been an extremely helpful tool inside and outside of lab.

Week 4 blog post Jordan Banyas

West Point Bridge Design is a fairly accurate portrayal of what it actually takes to make a bridge. It may not be the most accurate technology out there to create a bridge, but it is a nice introduction. It teach the fundamentals of bridge building to students who do not have a deep background of designing bridges. There are however many downsides of WPBD due to being beginners technology. For example, it has a height limit that is unrealistic to a bridge design. Another flaw is the inability to make a suspension bridge and even to put joints in certain points. Joints are only able to be put in on a fixed grid system which does not allow for much creativity. There are only a few designs that optimize the the forces of the truck driving across the bridge.
    This week I was able to shave off close to ten thousand dollars on our design we made in class. Our hope as a group is to improve upon our current design as well as continue to try and come up with a new innovative way to support the truck without spending as much money as we are spending now. Currently, my design costs us $215,858.44. we hope to make improvements this week.

Week 3 and Questions

This week our team worked on our first designs using west point bridge designer.  Although they were similar in theory, the way we created them and the prices were all much different.  In the next week and in lab, we will need to make the final touches on these designs and create a cheap and effective truss bridge.  To accomplish that, teamwork will be required and all of our ideas will need to be utilized.

In lab this week we have the engineering librarian coming, and we have created a few questions for him:

1.  Is there much research to be done on bridge engineering here at Drexel?

2.  What kind of books on bridges should we look for?

3.  Who are some famous bridge builders and what bridges did they create?

A1-Banyas

 

Sketch of Bridge Design

  

Bridge in Action

  

Data Table of Forces

 Initially I had a standard cross section in block formation that seemed to work very well but was very costly. The new design I came up with uses triangles as apposed to cross sections. By varying the angles I was able to balance the bridge is safe for the truck to drive over. This design only costs $343,413 and meets all of the requirements of building a safe bridge. I believe my bridge design could use work as there is still one beam that has a stress level over .95. From tinkering around with the bridge design technology I learned that it is very important to look at how much weight is put on the joints by hanging beam supports from them.

A1-Carr

The design for the present bridge had to support a moving object, the truck.  The difference that I had to account for was that the force being applied was different over time.  Therefore there had to be a constant patter throughout the bridge and it had to be symmetrical.  The use of triangles is evident in the design and they distribute the force appropriately.  As the truck moved across the bridge the top beams recieved the most stress but held strong.  One thing that could be improved is the strength of the top supports and to lower the weight of the material altogether.  The estimated cost for this bridge is about 350,000 dollars.  I do not forsee our group following this design because in the competition, the weight will remain stationary.  Therefore, I predict that the new design, using kinects, will distribute the force from the center.  I learned that to design a brige for a moving object is much more difficult than designing one for a stationary one.







 

A1- Greenwood

For this first design, I decided to keep a simple truss layout that would be cheap and effective.  The top of the bridge would slowly elevate until a central height was established, and underneath would be several trusses that jut out triangularly.  Considering this first week's assignment was to establish a design the team could build on and improve, I believed the simplest would also be the best.  Here are the images from my design as well as the stress tables and price.

                                         Above is the 2d design of my simple truss bridge.

Above is the 3d design of my bridge with a truck on it.

This is a picture of the stress table feature in WPBD.

During the design process of this bridge, the actual design changed many times.  For example, from my first design I added more joints and more trusses, considering the stress points in the joints were much greater when there were less.  Also, I made the max height of the bridge lower to make the flow of force through it more uniform.  Although adding more joints and trusses increased the price, it also gave me a working design.

Estimated Price : $347,715

This price is high as of right now, but I am confident it can be lowered.  There seem to be too many large trusses that need to be redesigned so that they are stronger and more capable of handling stress.

From this initial assignment, I have learned that simple designs can actually be successful and work.  I also believe that my knowledge can only increase so that I may be able to successfully build cheaper, stronger designs.