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Geodesic Greenhouse

The Alaskan island of Govandulz has been swamped by a tsunami and the inhabitants are looking for ways to grow food in the limited spring and summer season to replace the clams and oysters from the beaches that were destroyed by the tsunami.  Fortunately, the tsunami washed ashore a large quantity of 1/2-inch PVC pipe in 10-foot lengths, a large supply of 1 1/2" and 2"-long bolts, visqueen plastic sheeting, and waterproof packets of tomato seeds.  The plan is to build greenhouses from the PVC pipes and visqueen and grow tomatoes while waiting for the clam beds to reinstate themselves.  However the greenhouses must be designed to withstand the possibility of a freak snowstorm imposing a significant snow load on the greenhouse, and possibly significant lateral loads due to wind. 

(photo from http://drazium.com/mustard/dome/index.html)

Fortunately, the tsunami did not wipe out your internet connection, so you have access to the following resources:

bulletKenner, H., 2003. Geodesic Math and How To Use It. Berkeley, CA: University of California Press.
bullet Dave Anderson's Monkey House.
bulletLandry, T., 2002. "Desert Domes: The Dome Calculator," Desert Domes [accessed June 12, 2006] http://www.desertdomes.com/domecalc.html.

along with anything else Googlecan find.

The greenhouse domes should encircle a "circular" area with a diameter of 8 feet; its height is not specified, but it must allow for the tomatoes to grow at least 3 feet high.

Points will be awarded for how well your design performs with respect to:

bulletIts ability to withstand a vertical load of at least 10 pounds per square foot on the vertically projected area.
bulletThe total amount of 1/2-inch PVC piping required, and the number of connections.
bulletThe amount of wasted PVC pipe.
bulletAssembly time.
bulletProviding the minimum dimensions mentioned above, with a bonus for additional enclosed volume.

Note that the visqueen is not assumed to provide any structural strength and should not be included in your dome.  Other details will be provided as the semester progresses.

Design Process

This project is like many design projects you will encounter, in that it requires that certain steps be taken to successfully complete the project.  Here are the steps (Hyman, 1998):

bullet Recognize the need.  In this case, you need to complete the design project, as defined, to pass the class.  In Civil Engineering practice, the need is typically based on serving the public needs in some manner (need to build a road, need to treat the water, need to construct a hospital, etc.).  This step is where the purpose is established.
bullet Define the problem.  Clearly identify the goals, objectives, and constraints.
bullet Plan the project.  Break the project down into manageable tasks, and establish starting and ending dates for each task.  Note that in order to start a particular task, it may be necessary to first complete a different task!
bullet Gather information.  There is usually information available from similar projects, but each design situation is unique.
bullet Develop design alternatives.  Based on the goals, objectives, and constraints, a range of design alternatives are conceptualized.
bullet Evaluate alternatives.  Each alternative must be evaluated with respect to the goals, objectives, and constraints.  Also, economic considerations are critically important at this stage of design.
bullet Select the best alternative.  Based on calculations made in the previous step combined with engineering judgment, the best alternative is selected.
bullet Communicate the design.  Civil Engineers must communicate the results of their work clearly to clients, colleagues, government and regulatory agencies, and the public.  Effective oral and written communication skills are essential. 
bullet Implement.  In this step, the preferred alternative is executed, tested, analyzed, and modified if necessary.  The "as-built" performance is compared to the predicted/modeled performance.

Project Evaluation

Each team's project will be evaluated based on the following criteria:

bullet Competition results (20%)
bullet Aesthetics and creativity (20%)
bullet Written project report (40%)
bullet Oral project presentation (20%)

The written report will be evaluated for technical correctness, quality of writing, quality of presentation (formatting, graphics, etc.), and completeness.  It shall contain the following components (this list is not inclusive of what you are to submit - for example, you should have a letter of submittal):

bullet Introduction.  Includes the problem statement and objectives.  This is background information necessary for the reader to understand the rest of the report.
bullet Design.  Discuss design alternatives, performance predictions, calculation summaries, limitations, and constraints.
bullet Construction details.  Can someone else build your design given the information you provide in this section?  This include materials (simple!) and dimensions.
bullet Results.  How did it work?  Include calculation summaries and quantitative results.
bullet Conclusions.  Based on the results, describe what could be done to make the design better.  Also discuss how the performance could have been better predicted.
bullet Appendixes.  For this report, there should be at least three: your approved/signed initial design, detailed calculations, and the draft report.  You may see the need for others as well.

Schedule

Please see the Schedule page.

 

University of Idaho, Moscow, ID, 83844