Second year class competes in arch engineering competition
APT & National Trust for Canada 2017 Joint Conference
Willowbank’s Second Year Students, made the journey out to the nation’s capitol for the 2017 APT & National Trust for Canada Joint Conference, held October 11th to 14th. Our team prepared an informative poster and dry-stack arch to compete in the third and final phase of the Student Design Build Competition held by APT. There were three phases to the competition, which we entered into January 2017.
Phase One, consisted of the students studying a local stone arch and writing a structural report & case study about their findings. We decided to document the Niagara Customs House in Niagara Falls, which was built by Thomas Fuller in 1885, who designed the original parliament buildings. The structure has served many public service purposes, but has been sitting vacant for the last few decades. We received notice that we were advancing to the second phase of the competition just before Christmas of last year and that made the break that much more rewarding.
Phase Two, had of us create and test the load of a stone arch out of stone similar to the Phase One’s Customs House arch. Our studied arch was made out of Queenston Limestone. We opted to use Indiana Limestone with a traditional lime mortar, which has about half the compressive strength of the Queenston stone. The arch was built by hand on campus. Overall it supported 275 kg (606.27 lbs). We had a very strong entry and were selected to compete in to the finals in Ottawa as one of five schools. The building process and testing of our Phase 2 arch can be viewed at: https://www.youtube.com/watch?v=kJph_d5hsXc (Clickable Link)
Phase Three was a challenge, with tight restrictions and building guidelines, except one open element: what you made it out of, was completely up to our interpretation. With the competing schools identities being released: McGill, Carleton, Nebraska-Lincoln, and Texas A&M, we felt a little out our element, but we managed to come in very strong. Prior to our Ottawa trip, we had completed a timberframing course through our school program. We decided to incorporate leftover cuts from the pergola timber frame structure to create our arch, and laminated the salvaged materials. We used the shape of a Catenary arch — Robert Hooke noticed that a chain hanging by its own weight displays a shape corresponding to the equilibrium of tension shared by each link. This shape inverted into that of an arch similarly displays the equilibrium of its parts in compression. We created a model 3:32 of the original size and it was able to hold myself standing on it! After conducting the test we carried on to build the full scale arch. Our building method was solid which made cutting our arch voussures (pieces) difficult, but we managed and got Archie (as we called it) to Ottawa safe and sound.
We arrived in Ottawa prior to the competition. We used the time to explore the area, visiting Parliament Hill, Spark Street and Byward Market. Wednesday night we met the other teams and their members at a local pub, graciously hosted by APT. All the students decided to not share what we each made our arches out of until the reveal on build day. Friday was weigh-in-day: the other teams opted to make their arches out of styrofoam or plywood. Although our arch was the heaviest, we still came in under the weight restrictions.
Arch-build day was the final day of the conference, which gave us time to build up our excitement. When we assembled our dry-stacked arch, we had the second fastest construction time. Unfortunately we had to build on the separation line of two moving carpets. The testing was done with weighted boxes. A 13kg weight was placed first, and if the arch did not move then the weight was removed and replaced with a 20kg box. Our arch held the 13kg and first 20kg weight. When testing with a second 20kg weight it dropped the keystone 3”, but the arch still held. When the 13kg weight was added to the 40 kg, the carpets slid apart and it collapsed, yet we still managed to hold the most weight at 53 kg! If you know Willowbank though, that wasn’t good enough, and we knew we could hold more. We took our arch outside and re-tested it. We were followed by an audience, and all the other teams came to watch. The arch tested to over 100kg, and even with the abutments removed it still held. We felt pretty good.
When we started this competition, we didn’t know it would be this big of an event. At the conference we knew we surprised a lot of people that a “small school in a mansion” has so much to offer. We entered a Structural Engineering Student Contest, and we are not a Structural Enginnering School. Yet we managed to hand design, craft and build an arch that outshone engineering schools, while reusing salvaged sustainable materials. It was great example of the Willowbank Approach. The conference was an amazing opportunity to share Willowbank’s approach with so many heritage professionals and organizations. When the final results were announced, we came in third out of eleven teams from across North America and received two of the three special awards: Best Video and Best Build. I am proud of the entire team and so thankful for all the support from the Willowbank community.