Bridge in the crushing vice.Anxious students look on as technologist Lucian Pop (centre) crushes their model bridge during a competition Wednesday in the Centre for Engineering Innovation.

Bridge-building competition provides model for real-world engineering work

Building structures of popsicle sticks and glue is a common activity for elementary schoolchildren, but it takes an engineer to predict their strength and performance.

That’s the reasoning behind a unique competition for students of Amr ElRagaby’s third-year civil engineering class, Finite Element for Analysis and Design. Teams are tasked with designing and constructing a truss bridge at least 10 cm wide and 75 cm long. They are exposed to concentrated load until they fail by breaking or bending.

“We are trying to enhance their learning by giving them hands-on experience,” says Dr. ElRagaby. “They have fun and they appreciate how much they have learned.”

The students pitted their structures against each other Wednesday in a contest that rewards creative and innovation designs that bear the most weight relative to their own, along with the most accurate predictions of their strength.

“Once the students have built their bridges, they analyze it using specialized software tools and make some predictions about how they will perform,” ElRagaby says. “Then we verify it under our experimental conditions,” placing each structure in a specially-built machine that measures the force applied as the structures are crushed.

“We learned a lot, applying theory from class into a real model,” says student Chi Nguyen. “The difficulties and obstacles we encountered are part of what we need to deal with as professionals.”

The best performing bridge—a triangular design by Abe Abou, Ali Ahmed, Chris Lemmon and Ryan St. Pierre—held more than 135 kg with just 1.4 mm of deflection, while weighing just 511 grams. Watch a video by Martin Vaughan of the Centre for Teaching and Learning of their results:

The students shared a cash prize of $350, as did teams judged to have the most creative design and who provided the most accurate prediction. Sponsors included Stantec engineering firm, Canadian Deck and Joist Corporation, the Falkner family, and the Department of Civil and Environmental Engineering.

Students hold popsicle stick bridge model
Third-year civil engineering students Naeim Farahi, Navjot Singh and Sachith Jayasuriya display their model bridge, a winner for most creative design.