This paper describes about post earthquake investigation to clarify the failure mechanisms on three cases of river dike failure caused by recently occurred Kushiro-oki, Hokkaido Nansei-oki, and Hyogoken-nanbu earthquakes. The change of policy on rehabilitation works of seismically damaged dikes was also presented through the description on the modification of technical standards on river dike construction.
Restoration works of civil engineering structures damaged by earthquakes have long been conducted in a manner to rebuild as they were before the earthquakes. No remedial measure was admitted for restoration works due to financial constraint. However after the case of restoration works of damaged dikes by the Kushiro-oki earthquake, it became to conduct remedial treatment of foundation ground if necessary.

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This paper presents a new monitoring system with fiber-optic communications net. Fiber-optic communications net is under construction speedily in Japan and use of that is very effective for the bridge management. This monitoring system consists some kind of sensors (strain-gage, peak strain memory sensor, temperature sensor), amplifier, analog-to-digital converter, control system, electric-to-optic converter at the Osaka-bridge, fiber-optic communications net and optic-to-electric converter, work station at Tokyo Institute of Technology. With this system, it will be possible to measure strain, peak strain, and temperature with various kinds of sensor. Moreover, gross weight of truck can be calculated by means of the obtained data immediately as in field measurement.

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The durability of concrete exposed to cold climate for 50-several years was evaluated by various methods. As the result, it was recognized that the compressive strength of core specimens were remarkable development from 1.8 to 2.0 times compared to that of specimens cured for 28 days at constant temperature in water at the construction. It was originated from that the cement was coase and was consisted of many belites. The quality of concrete was correspondent to manufacturing performance of the precast concrete, judging from the average carbonation velocity coefficient, and it was proven that the good construction was carried out. The degradation by carbonation and so on had stopped only in the surface layer.

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The objective of the present paper is to demonstrate a prevention technique of rust. Honshu-Shikoku Bridges consist of seventeen steel bridges across the straits. Oomishima Bridge is the first bridge constructed by Honshu-Shikoku Bridge Authority to span the strait. Therefore, prevention of rust is of great importance. In this paper, we shall focus our attention to the following three points: (1) developing new techniques for rust prevention; (2) R & D of rust prevention bolts; (3) development of rust prevention techniques for hanger ropes. As a result of detailed inspections, anticorrosion treatment of the Oomishima Bridge is considered to be in good condition.

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This paper proposes the design method in which the secondary lining is considered as the reinforcing member, referring to the latest research results. The study using this method was carried out for existing shield tunnels of the Teito Rapid Transit Authority, which had been affected by the adjacent construction works.
According to this study, it was found that the existing shield tunnels were secure and the economical reinforcing work became possible.

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In this study, a new method is suggested to determine the rule for train operation control on bridges under floods. In the method, the drop in natural frequency of a pier with reduction in the supporting power of fundation caused by scour is considered. And it was verified that the measured natural frequency obtained through dynamic percussion test coincides with the calculated one obtained through dynamic analysis based on the relationship between scour depth and natural frequency of the pier.
This rational and generally applicable method, which has already been proved on the site excavation tests of bridge piers on the Tokaido Shinkansen, can also be applied to road bridges.

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A new composite foundation of pile with soil improved is proposed to resistant intensive seismic horizontal force. Soft soil at the shallow depth is improved by cement mixing method. Piles are constructed through the cemented soil mass in order to transmit vertical loads to bearing stratum. Two in situ horizontal loading tests were performed to confirm their behaviors. It is shown that the horizontal bearing capacity was much greater than that of pile only, and the cemented soil mass and piles worked as a mass when the displacement is less than 1% of the width of the foundation. 3-D FEM analysis is conducted to confirm the mechanism of bearing capacity of the new foundation. A simple design spring model of the composite pile foundation is proposed here.

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This study proposes a new information infrastructure for policy discourse. Recent literature on decision support systems evokes the need for an alternative approach to the traditional normative model of public consensus-making. This study has thus introduced an argumentation model based on informal logic. This model was incorporated into CRANES, a group support system that primarily aims to visualize the balance of public arguments. CRANES was then applied to two sets of public arguments: one about an urban regeneration scheme in London; and the other about an infrastructure development project in Japan. Results support the technical feasibility of the system as an alternative public medium for promoting participative policy-making.

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It will be very important for taking measures of tunnel support in either rational or economical way to know either strength or deformability of rock mass at the tunnel face quantitatively. In the paper, the authors propose a new rock mass classification method based on observational results obtained at the tunnel face, which will enable to know appropriate amount of support measure. The study is confirmed by the database consisting of 6, 101 sections of tunnels constructed by Japan Highway Public Corporation. The paper additionally discusses the contribution of rock condition against the mechanical rock properties and ground water inflow. An application of the method to the real tunnel construction is also illustrated and the results of application become agreeable reasonably.

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This report examines the mechanisms of the impermeability used in a new water-expansion rubber material of injected type. Until now, Impermeability of segment joint of shield tunnel was retained by increasing contact surface stress between segment by pressing. However, it is very difficult to retain the impermeability in the complicated joint plane. Then, a new water-expansion rubber material of injected type has been developed. we researched the mechanism of impermeability because it was indicated that the mechanism differed from conventional contact surface stress. As a result, we found a mechanism of impermeability by blocking effect. From this mechanism, it was possible to predict the critical impermeability pressure by a semi-theoretical equation based on the equation of the extrusion.

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This paper presents the analysis algorithm on the influences of the planner's intention in the land-use capability classification applying the Analytic Hierarchy Process (AHP) method. The land-use capability classification maps are integrated as the criteria-parameters for the pairwise comparison of the AHP operations. Based on the weights of those criteria-parameters, the compromised area considering the both intention of the “development and preservation” are visually zoned on the “mutual regulation map.” Furthermore, the alternative areas extracted by changing the pairwise comparative matrices in accordance with the planner's intention are newly delineated on the “influence analysis map.” This influence analysis map and its interpretation are useful as supporting information for land use plan and planning.

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