M. K. Hurd, ASCE Member
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Civil engineering students from Illinois and Purdue universities in May staged what is believed to be the world's first concrete canoe on the Inland Sea, a tiny lake in east-central Illinois. The Illinois canoe weighted in at 360 lb (163 kg) compared to a mere 125 lb (57 kg) for the Purdue canoe. Although pre-race odds heavily favored Purdue, Illinois emerged the victor winning three of five heats on the 1240 ft (317 m) course. (Note that the conversion is incorrect. But, since 317 m translates to 1040 ft, the "2" was probably a typo.) Fastest time for an individual heat was 2 minutes, 46 seconds. (We travel this distance today in approximately one half that time.) The two schools were about evenly matched as to the number of students dunked in the lake but the Illinois win was attributed to greater expertise with the paddles.
Both canoes were made of ferro cement, a special form of reinforced concrete, made of several layers of small-gage wire-mesh reinforcement embedded in a thin section of rich mortar. (Sounds pretty much like the "adaptive reinforcement" that we use today.) Differing from ordinary reinforced concrete, its behavior approaches that of a homogeneous material, and some designs have been made based on the assumption of equal tensile and compressive strength. (Why didn't we read this before we started in 1986? This is the assertion that we made in our 2001 design report; it only took us 15 years to come to that conclusion.)
The whole affair began nearly two years ago when University of Illinois civil engineering students under the guidance of Professor Clyde Kesler, a fellow of ASCE, built the "Mis-Led." They used #3 reinforcing bars bent and welded at each end of the canoe to make the gunwales and keel. A single rib of #3 bar was welded to the gunwales and keel at mid-length. Four layers of chicken wire (At least we referred to this in the late '80s as a "poultry restraining device" to give our reinforcement's name a high-tech ring.) were placed over this frame.
A stiff mortar was troweled onto the wire mesh. Final thickness of the the hull averaged 0.5 in. (13 mm). No forms were used.
When Professor John McLaughlin, member of ASCE and head of civil engineering at Purdue, told his students of the Illinois achievement, they decided to build their own canoe and to challenge Illinois to a race. With guidance from Charles H. Scholer, and Robert H. Lee, members of ASCE and civil engineering professors at Purdue, the ASCE Student Chapter took on the project, adapting plans for a conventional racing canoe. Unlike the Illinois team, Purdue created a mold of insulating foam plastic to the exact contours of the canoe's interior and covered it with thin plastic sheeting. (Wait a minute! I know a lot of schools who claim to have done this first.) Over this they assembled their reinforcement to the desired shape. They also used four layers of chicken wire netting (There they go again stealing our claim to multi-layered "adaptive reinforcement."), with supplementary reinforcement of #2 bars laid along the keel and gunwales. Their lightweight mortar was plastered onto the mesh to create an average shell thickness of 0.375 in. (10 mm).
Foamed polystyrene plastic blocks, built in at each end and encased within the mortar shell, provided positive buoyancy for the Purdue canoe. (Well, at least we've made some progress in this regard. But, after 30 years, I guess that we should.)
First prize was a slender shaft of exposed aggregate concrete, mounted on a sawed concrete base and topped by a plaster-of-paris canoe model. Another trophy, created by the Purdue ASCE group, was a concrete "life preserver" made of normal weight concrete so heavy that two men were required to lift it. (Hey, I want one of these babies in our trophy case. To heck with those shiny gold cups that they give out now. - Maybe I can get Illinois or Purdue to put them on e-bay and get ASCE to make a bid. These keepsakes would certainly make nice trophies for the 150th anniversary.)
Cheered by the success of this first race, the two student groups expressed the hope that the concrete canoe race might become an annual event with participation by other ASCE Student Chapters within canoe-hauling distance of a point halfway between West Lafayette and Champaign-Urbana. How about it Rose, Notre Dame, Northwestern, etc. (No one could have imagined how far we would come.)
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