ALFRED A. YEE
Perspective: Structural Engineering
IAN ROBERTSON
Ian Robertson is the Chair and Arthur N.L. Chiu Distinguished Professor in the Department of Civil and Environmental Engineering at the
University of Hawaiʻi at Mānoa.
I don’t recall when I first heard a presentation by Al Yee, but I know that I will never forget the content of the presentation. He told stories of developing concrete barges when steel supplies were low after the second world war and how some of these barges are still in operation today. His ongoing passion was to use this technology to support Ocean Thermal Energy Conversion (OTEC) stations to provide renewable energy for Pacific Island nations. He described the folded concrete slab roof structures he designed for aircraft hangars, and the modular prefabricated housing units that could be stacked multiple stories high with all utilities already installed in a Henry Ford-style fabrication plant. He implemented this approach on a limited scale in Aiea but on a much larger scale in Singapore, where he spent much of his time.
As an adjunct professor in the Civil and Environmental Engineering department at UH Mānoa, Al Yee made several presentations to student groups. These presentations were always inspirational, encouraging the students to think innovatively but to validate their ideas through analysis and testing. He stressed the need to understand and apply the fundamentals of engineering principles, rather than relying solely on sophisticated computer analysis.
I had the pleasure of working with Al Yee on one of his inventions. He had an idea for precasting concrete slab panels so that they could be used to replace concrete pavement during an overnight operation, thereby reducing the interruption to traffic. The tricky part of this concept was making the connections between adjacent panels so that they would not displace even under heavy truck loading. We set up a testing apparatus in the structures laboratory to use our hydraulic load frames to test the capacity of his “kwikslab” connection concept. It looked a little like a keyhole in one slab with a headed rebar sticking out of the other slab so that when you set the headed rebar into the keyhole and grouted around it, you essentially had created a continuous piece of rebar from one panel to the next. Our tests showed that the kwikslab connection was extremely strong and capable of ensuring continuity of the reinforcement across the joints between precast panels. Similar systems are now being used by Departments of Transportation around the US and are also being considered for use here in Hawaii.
As an adjunct professor in the Civil and Environmental Engineering department at UH Mānoa, Al Yee made several presentations to student groups. These presentations were always inspirational, encouraging the students to think innovatively but to validate their ideas through analysis and testing. He stressed the need to understand and apply the fundamentals of engineering principles, rather than relying solely on sophisticated computer analysis.
I had the pleasure of working with Al Yee on one of his inventions. He had an idea for precasting concrete slab panels so that they could be used to replace concrete pavement during an overnight operation, thereby reducing the interruption to traffic. The tricky part of this concept was making the connections between adjacent panels so that they would not displace even under heavy truck loading. We set up a testing apparatus in the structures laboratory to use our hydraulic load frames to test the capacity of his “kwikslab” connection concept. It looked a little like a keyhole in one slab with a headed rebar sticking out of the other slab so that when you set the headed rebar into the keyhole and grouted around it, you essentially had created a continuous piece of rebar from one panel to the next. Our tests showed that the kwikslab connection was extremely strong and capable of ensuring continuity of the reinforcement across the joints between precast panels. Similar systems are now being used by Departments of Transportation around the US and are also being considered for use here in Hawaii.
Creative minds abound, but very few of them have good enough ideas, or have enough motivation and stamina to see them through to implementation. Al Yee was one of the few who could take an idea through development, testing, code adoption, and into practice. He was an inspiration to me and undoubtedly to many others in Hawaiʻi and around the world. Hawaiʻi was incredibly lucky to have one of these true innovators active in our community.