Site: Shimizu Institute of Technology
3-4-17 Etchujima, Koto-ku
Tokyo 135, Japan
Date Visited: October 1996
Hosts: Dr. Eng. Terry Nakatsuji, General Manager, Shimizu Corporation
Mr. Kenzo Sekijima, Senior Research Engineer
Dr. Eng. Eiji Ogisako, Senior Research Engineer
Mr. Junichi Iketani, Research Engineer
Mr. Keisuke Yonemaru, Research Engineer
Summary: (a)Research and development in the area of materials and structures.
(b)Applications for NEFMAC and NESTEM.

BACKGROUND

Founded in 1944, the Shimizu Institute of Technology is the oldest technological construction research laboratory in Japan. It is one of the R&D organizations of the Shimizu Corporation. As it enters the 21st century, the Shimizu Institute of Technology aims at being able to "organize original, creative research and development activities" in the future under the motto of "Progress and Harmony." The objective is to achieve technological advancement and space expansion and coexistence with nature under all circumstances as well. In 1995, it had a research budget of $6.0 billion and a total R&D budget of $12.6 billion. In total, the research staff number 356, of which over 200 are at the Institute of Technology.

ACTIVITIES OF INTEREST

The Institute of Technology has extensive facilities in the following 16 separate laboratories:

  1. Structural Testing
  2. Multipurpose Testing (x-ray, electron microscope analysis, environmental chambers, soil testing)
  3. Vibration Testing
  4. Wind Tunnel Testing (capable of testing full bridge and city models at wind speeds up to 30 m/s - Figs. B.33 and B.34)
  5. Rock Testing
  6. Clean Room
  7. Ultra-Clean Room
  8. Hydraulics Testing (including a 40 m long, 4 m wide and 1.3 m deep wave tank)
  9. Acoustics
  10. Environmental Simulation
  11. Water Environmental Testing
  12. Bioengineering
  13. Cryogenics
  14. Fire Testing
  15. Geotechnical Centrifuge
  16. Vibration Control Testing

Shimizu serves as the chair of the CFRRA and undertakes significant research and testing on the application of Tonen's tow sheet to concrete. Current research in this area has emphasized the adhesive properties of the epoxy and the tow sheet composite to concrete, including developmental length, effect of thickness and number of layers, and level and modes of fracture.

Although NESTEM is now a commercial product in the geotextile area, there is still a large amount of research being conducted on pull-out properties, applications technology and the development of a better product.

When first introduced, the grid type NEFMAC reinforcement was fabricated using glass, carbon and aramid fibers. Based on studies conducted on the effects of long term creep, durability, UV resistance and fire resistance, the current emphasis is on carbon, aramid and hybrid reinforced grids only. Applications range from slab and wall reinforcement to reinforcements for bridge repair, shafts of shield tunnels and floating piers (Figs. B.30-B.32).


Fig. B.30. Use of NEFMAC reinforcement for repair and retrofit of a bridge deck.


Fig. B.31. A NEFMAC cage as reinforcement for the shaft for a shield-cuttable tunnel.


Fig. B.32. Reinforcement for shotcrete in tunnels.

Current research emphasizes the use of NEFMAC as a security sensor through its application in a carbon-glass hybrid form of grid reinforcement in concrete walls. The conductivity of carbon is used as a signal, thus enabling its use as an "intelligent material."

There also is significant research on the design, analysis and fabrication of a composite (carbon/phenolic) space truss system for use in roof and large span structures. The tubular elements are expected to result in significantly faster construction of maintenance free structures, lighter structures that will be modular and easy to mass produce.

Work is also being conducted on next generation cities and tower type living environments (Figs. B.33 and B.34), which would be constructed out of advanced materials such as composites. They would initially rise 400 m above a city block and be capable of upward expansion, one block at a time in multiples of 200 m. This work is being aggressively pursued as a means of alleviating future space constraints and as a means for developing new enabling technologies and materials. Research is also ongoing on the development of materials and structural components for a large truss type pyramidal structure that would serve as its own system, with living space formed between truss type elements and the truss tubes serving as a mass transit system.


Fig. B.33. Artists rendition of the step over tower structure (with over tower configuration).


Fig. B.34. Schematic of the step-over tower configuration.


Published: October 1998; WTEC Hyper-Librarian