UA Civil Engineering Students Take Their Designs from Concept to California

By Steve Delgado and Aaron Maciosek - April 9, 2012, 3:22 pm

Students from the University of Arizona chapter of the Society of Civil Engineers recently competed in the annual Pacific Southwest Conference of Student Organizations of the American Society of Civil Engineers, taking no disqualifications while placing second in overall bridge design.

The PSWC 2012 at the Cal Poly campus in Pomona, Calif., is sponsored by the national ASCE and is an annual meet bringing together civil engineering programs throughout Southern California, Southern Nevada, Hawaii and Arizona. The event is fully student-run and gives civil engineering students the opportunity to develop leadership skills and apply classroom concepts by competing in events like the concrete canoe and steel bridge competitions. This year's event hosted 18 regional engineering schools.

Concrete canoe stress
The concrete canoe representing the UA, dubbed "The Black Widow," was over 20 feet long and nearly 3 feet at its widest point.

The boat was cast using lightweight concrete engineered by students to be less dense than water, but strong enough to withstand the rigors of carrying up to four people for racing. The final UA engineering concrete canoe weighs 270 pounds.

The Black Widow was also reinforced using a steel wire pre-stressing system, a method not utilized in previous years, said UA civil engineering senior Peter Strunk. "Concrete is typically around ten times stronger in compression than it is in tension," Strunk said. "To prevent the thin walls of the canoe from cracking, the concrete was placed around 10 steel wires that were tensioned at 250 pounds each… when the concrete cured, the tension on the wires was released, and the wires pulled the sections of the canoe into compression." This prevented tension zones from being created in the walls of the canoe, and prevented cracks from appearing in the concrete, he said.

The Black Widow, captained by Strunk, was judged on aesthetics, racing ability and accompanying oral presentation and technical paper. The canoe earned 7th place in PSWC overall standings.

Optimized steel bridge takes second in design
Attendees of the Science City section in this year's Tucson Festival of Books in March got a sneak peek at the steel bridge just days before the students, led by UA civil engineering senior Aaron Maciosek, trailered the structure and drove it to California to compete in the PSWC.

To compete, the steel bridge had to fit within several dimensional requirements, and still be as structurally efficient as possible, Maciosek said. "The shape of the bridge and the sizes of the bridge members were optimized to reduce weight wherever possible, without sacrificing the strength of the bridge," he said.

In addition to structural soundness, a large majority of the bridge competition involved timed construction, which influenced design considerations to keep the total number of pieces and connections as low as possible. The final steel bridge design measured 23 feet long, 5 feet tall, and 4 1/2 feet wide.

The final version of the steel bridge was composed of 146 pieces, totaling approximately 375 pounds. In competition, UA civil engineering students were able to build it in less than 40 minutes. During the load portion of the competition, the bridge held 1,450 pounds and only deflected (moved) ¼ inch, earning second place in overall design and aesthetics.

Industry sponsors for the UA concrete canoe include Sun Mechanical, Saint-Gobain Adfors, APWA-SA, Beyond Cabinets, Cemex, Ciccone Design, MJI Company, Burgess, Rapidset, Anderson Painting Company, Southwest Construction Supply, Grace Construction Products, M3 Engineering and Technology, and Freeport-McMoran Copper and Gold Inc.

Sponsors providing support for the steel bridge include M3 Engineering and Technology, CAID Industries, Anderson Painting Company, Fastenal, TMM Precision/The Metal Man, and Weldrite Welding Repair.

You can view a photojournal of the competition by clicking on the slideshow above or the link here.


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