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CE Club Update

Hillcrest CE Club Recap

On March 4^th, shortly after participating in a discussion about mechanically-stabilized earth (MSE) structures and geotechnical engineering, students of Hillcrest High School’s Civil Engineering Club teamed up for a friendly competition; the objective: to design and construct a self-supported, earth structure consisting only of sand and window screen and capable of resisting the greatest load amongst the teams. Four teams were formed and provided approximately 15-minutes to achieve the objective.

Using just a few, unsophisticated tools for placement of the sand (a scoop), cutting of the window screen (scissors) and compacting of the soil (a brick), the teams of students quickly went to work building their MSE structures. The earth structures were constructed within a wooden form that would be removed after completion. To qualify for the competition, each team’s MSE structure had to remain “intact” upon removal of the forms. Each team successfully achieved this task. As such, the loading of each structure began. Using bricks, each MSE structure was loaded to failure/collapse. Three of the four eventually succumbed to the load of the bricks; however, one team’s mechanically-stabilized earth structure resisted. Ultimately, one student (and all 200 pounds of him), with the support of his colleagues, stood on top of the earth structure. To everyone’s amazement, the winning team’s MSE, resisted the load with negligible deflection!

The purpose of this activity, as presented by Reece Taylor and Jeffery Joseph III of Braun Intertec, was to demonstrate how the use of artificial materials, such as geosynthetics (or in this case window screen), can be used to provide tensile strength to earth materials (e.g. hold the soil together), as well as significantly increase the ability of earth materials to resist loads. The presentation also included several examples of how MSE structures are often used to construct the infrastructure (roads, bridges, slopes, buildings, etc.) within our communities.