Approximately ¾ of the 20 students enrolled in the section had opted for Civil Engineering as their major, the rest were undecided. There were more CE students in other sections, where they build truss bridge for their project and conducted environmental engineering experiments.
The class was divided into four groups of five students each. Two of the groups were asked to build walls using poster-board facing and kraft paper strips, while the other two groups build wrap-around walls using paper towels.
Over the entire semester, ten hours were allotted for the project (the remaining hours for the course included classroom lectures/lab/demonstration in different areas of engineering). We met approximately every four weeks at the beginning, with more frequent meetings at the end of the semester.
I spent the first two hours on a class room presentation that covered topics ranging from the basic principle behind reinforcements to different types of reinforced soil systems, with a lot of visuals showing different types of MSE walls, including cross section views.
The remaining four meetings of two hours each were spent with students attempting to build the paper-reinforced walls. After the first day in the lab, each group was asked to prepare a short write-up explaining what the problem was (as they understood it) and their proposed approach and rationale behind it. This is where they had to discuss items like: shape of potential failure surface, should the reinforcement extend longer at the top or the bottom, where would the spacing have to be greater, whether it helps to have transverse members, whether the reinforcements should all be flat or should be at angles to the horizontal, etc.
Since these were first semester freshman students, the approach was entirely qualitative and intuitive, verified through trial and error. They were not introduced to any calculations or theory. In the lab, they were challenged to progressively use less reinforcement and judiciously select where to put them.
Each group kept track of how much paper reinforcement they used in each attempt. They did not compete in terms of comparing quantities between groups, but were required to progressively reduce compared with their own previous use, until the wall failed.
After the final design, each wall was able to withstand much more than their targeted 50 lbs surcharge. Most were able to withstand the weights of two students standing together.
At the end of the semester, each group made a 10-min presentation on their project in front of judges and peers. They also prepared a poster presentation.
For additional information on this work, please contact Anirban De.