Guest Blogger: Elizabeth Wroe

by Michael Mullaney on April 12, 2012

(Civil Engineering senior Elizabeth Wroe wrote this excellent post for The Approach. It’s about an engineering competition last month in Oakland, Calif., where she and her teammates won second place. Enjoy!)

On March 26, a group of RPI students placed second in the annual Geo-Institutes GeoWall competition. The four students on the build team were Margaret Exton, Russell Jones, Panagiota Kokkali, and Leonard Lustrino.

As champions of last year’s competition, the RPI team fought hard to keep their title. Unfortunately, in classic bottom-of-the-ninth style drama, the final competing team managed to build a strong stable wall and steal away the prize.

The GeoWall competition is a contest to determine which team can build a retaining wall out of poster board and Kraft paper using the least amount of material. Between the final weight of the Kraft paper used, a report score, and any deductions that may have been incurred due to rule violation, each team receives a total score. If the wall fails under the loading, the team is disqualified. RPI came in second with a total of 159.2 points. Surrounding Rensselaer’s second place finish were CalPoly Pomona in first place with 182.5 points and CalPoly San Luis Obispo in third with 152.5 points.

The RPI team, which also includes alternates Derek Lousch, Jessica Stratton, Christopher Snyder, and Elizabeth Wroe, had been working on the final wall design long before their trip to Oakland. Over the course of sixth months, the team tested paper and soil parameters and built many different wall designs.

Beyond basic tensile tests of the paper, and shear tests for the soil, the team went so far as to establish their own pullout test for the paper strips. This test helped establish whether the strips were breaking under the load conditions or simply “pulling-out” of the soil due to insufficient friction between the sand and the paper. While pullout tests do already exist, the team had to modify the original testing materials to correctly represent the unique conditions of the paper retaining wall.

In addition to having a strong design and low paper weight, it is very important to construct and install the wall under the time limit set by the competition. After eventually deciding on a design and submitting the report, the RPI GeoWall team spent many weeks practicing to build the wall within the set time limits. Averaging at around one wall per week, sixteen separate retaining walls were built and tested to help calibrate team members to the competition standards.

The competition featured four heats based upon weight of the paper reinforcement. Having a relatively above-average paper weight, RPI competed in the second heat along with four other schools. Disqualifications were common, as a team’s wall had to stay intact under various loading conditions for a length of time. Only six teams were given a score.

After RPI’s wall held, the team had to wait anxiously for the following ten school’s designs to fail. Because all following teams had less design weight, they had a greater chance of receiving a higher score. Fortunately, for the RPI team, deductions were as common as failures. For example, each team was responsible for building and bringing their own box and any deviations from the specifications given in the rules were eligible for deductions. RPI’s relatively high report score and lack of deductions gave them a high lead early in the competition.

The competition was held in Oakland, Calif. this year at Geo-Institute’s annual GeoCongress conference. Along with presentations and exhibits, the gathering also featured two separate competitions as part of the GeoChallenge: the GeoPoster, a contest between research posters; and GeoPredictions, a contest where each team of students is presented with a real-world civil engineering problem and is asked to present the most reasonable geotechnical engineering solution. Next year’s GeoChallenge will be held in San Diego.

(Professor and friend of The Approach Tarek Abdoun is the faculty adviser of the Rensselaer GeoChallenge Team. For more on the team, click here and here.)