2019 Innovative Technique Award
1. Development of Automatic Placement System of Dam Concrete
- Yamashita Norikazu
- Moriyama Shinobu
- Tachihana Subaru
- Mori Hideo
- Kase Toshihisa
In the construction of a concrete gravity dam, the concrete placing accounts for about 60% of the dam construction cost and about 50% of the term of construction work. In addition, it requires tens of thousands of repeated concrete works. Furthermore, many skilled technicians are required. The effects of the present technology include improvement of the placing cycle time, cost reduction by reducing the number of workers, and elimination of a shortage of skilled technicians. In particular, by streamlining the operation of the track-type cable crane by fully automatic operation, it is possible to improve the delivery and the cost.
2. Development of Shear Strengthening Method Using Shear Reinforcing Bar with Ceramic Anchorage (Ceramic-Cap-Bar)
- Shinichi Yamanobe
- Naoki Sogabe
- Keigo Tamano
- Takuya Iwamoto
- Masaaki Ueda
Ceramic-Cap-bar (CCb) method is a shear strengthening method for seismic retrofitting that uses deformed reinforcing bars with ceramic anchorage caps at both ends. CCb can be installed to the existing underground structures from the inner space side, to enhance the shear resistance of the structure. Since ceramic is a non-ferrous material, the usage of it as an anchorage enables high durability as well as ensures the shear reinforcing effect of the bars. This method has been applied to a wide range of existing structures, and it has been continuously improved to adapt to the complex design and installation condition of various underground structures..
3. T-iROBO®Remote Viewer: HMD Video System for Remote Control with high adaptability
- Takashi Kato
- Takashi Imaishi
- Jun Ueno
- Yoshio Nishida
- Hayato Kinoshita
The author has developed a video system for the remote operation of construction machines in hazardous areas that provides a realistic sense of the actual situation, T-iROBO® Remote Viewer. With conventional video systems, it is impossible to get a realistic sense of distance because monocular camera images are used. With this system, the operator wears a head-mounted display (HMD) to remotely operate a construction machine, giving a realistic feel for distances at the site. This system does not require multiple monitors and can be built anywhere using HMD. As a result, a system can be constructed in a short time.
4. Development of field test methods on rock masses as element tests
- Tetsuji Okada (Central Research Institute of Electric Power Industry)
- Kazuo Tani (Tokyo University of Marine Science and Technology)
- Tomohiro Naya (DIA CONSULTANTS CO., LTD.)
Methods for in-situ triaxial compression test and in-situ direct tension test on rocks were developed as element tests. Using these testing methods, average stress-strain relationships of rock masses which are usually discontinuous, heterogeneous and non-uniform in nature can be measured under well-defined initial and boundary conditions using the same principles as various laboratory uniaxial/triaxial test methods. Thus, both deformation and (shear and tensile) strength characteristics of rock masses can be rationally evaluated. Some of their technical developments include a sophisticated method for specimen preparation, highly accurate measurement of deformations and a simple loading mechanism. With these innovative technologies, rational designs of safer rock structures will be realized.
5.Development of Precast Deck Connection (Slim-Fastener) using UFC
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- Toshio Nomura
- Takayuki Iwaki
- Takayuki Tominaga
- Takashi Kawanishi
- Kazunari Sasaki
This technology is a precast deck connection with the interface of multi-shear key shape, using Ultra high strength Fiber reinforced Concrete (UFC) as the filling material. The UFC reaches 180 N/mm2 of compressive strength without heat treatment, making it possible to manufacture, cast and cure at site, which can shorten the process. By using UFC, the embedded length of the steel rebar in the bridge axial direction is 6.5 times of the rebar diameter, making the width of the joint about half that of the conventional method. It can also reduce the labor force on the site because the steel rebars in the direction perpendicular to the bridge axial are not needed. In addition to the high durability of UFC, as the multi-shear key shape suppresses the opening of the interface, it leads to a supreme durable and solid connection.
