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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:
along with anything else Google™
can 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:
 | Its ability to withstand a vertical load of at least 10 pounds per
square foot on the vertically projected area. |
| The total amount of 1/2-inch PVC piping required, and the number of
connections. |
| The amount of wasted PVC pipe. |
| Assembly time. |
| Providing 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):
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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. |
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Define
the problem. Clearly identify the goals, objectives, and constraints. |
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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! |
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Gather
information. There is usually information available from similar
projects, but each design situation is unique. |
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Develop
design alternatives. Based on the goals, objectives, and
constraints, a range of design alternatives are conceptualized. |
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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. |
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Select
the best alternative. Based on calculations made in the previous
step combined with engineering judgment, the best alternative is selected. |
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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. |
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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:
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Competition results (20%) |
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Aesthetics and creativity (20%) |
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Written project report (40%) |
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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):
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Introduction.
Includes the problem statement and objectives. This is background
information necessary for the reader to understand the rest of the
report. |
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Design.
Discuss design alternatives, performance predictions, calculation
summaries, limitations, and constraints. |
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Construction
details. Can someone else build your design given the information
you provide in this section? This include materials (simple!) and
dimensions. |
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Results.
How did it work? Include calculation summaries and quantitative
results. |
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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. |
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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.
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