[in Japanese]

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When an auger excavator is used to construct various piles and underground consecutive diaphragm walls, it is usually managed by estimating the soil stratum in the construction area based on the result of preliminary boring investigation. In order to develop a new method for managing construction objectively and accurately, the authors proposed a technique that can detect the changes in ground stratum while drilling with the auger excavator, taking notice of vibration during drilling with the auger excavator, and then proved its validity by a field experiment. From the results of the experiment, there was a possibility that real-time judgment of the changes in ground stratum could be made through the vibration measurement of the auger excavator.

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The nondestructive tests for concrete structures have been conducted for the purpose of quality control and to estimate damages. However, there doesn't exist any precise standards for judgement and estimation of damages. Early establishment of nondestructive tests which are applicable for concrete structures is required from the point of view of the preventive maintenance. Therefore, the nondestructive tests using the impact elastic wave or the ultrasonic pulse wave were applied for the void investigation in concrete structures. Based on the results of tests in model slabs and in real concrete slabs of road structure and tunnel lining, it was confirmed that the nondestructive tests are applicable for the void investigation by observing the wave and analyzing the spectrum of dominant frequency.

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The aim of this study is to develop a practical application of concrete bridge rating expert system. In this study, an explanation function and a knowledge acquisition support function are newly developed. The former function allows a fuzzy reasoning process of the expert system to be explained to system users. In the latter function, a learning method proposed in this study is applied to allows an acquired knowledge to be concretely shown to users. Furthermore, comparisons between the diagnostic results before learning and the ones after learning are presented so as to demonstrate the validity of learning capability of this system.

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Since its inception approximately half a century ago, the Japanese engineering industry (or process-plant contractors) had developed into a substantial part of the E & C industry of Japan. After a successful period for almost 30 years, however, they now face formidable difficulties in the world-wide economic depression. Unless regaining competitive advantage in the global market, the Japanese firms may not be able to survive. This paper firstly studies the global process-plant market, then analyses the competitive advantage of the engineering industry, and finally proposes measures to restructure the Japanese engineering industry.

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In this paper, we suggest an analytical model of an OR tire for running performances prediction, and report analysis of fundamental deformation behavior of a tire. The function of the OR tire was analyzed from the structure which divided in two blocks of tread department and sidewall department. The approximate polynomial expressions of the relationships of the load-deflection and also contact length-deflection were investigated by the load test. And two equivalent elastic moduli were estimated by the results. We consinhcted a discrete tire model by RBSM (Rigid-Bodies Spring Model). The calculation value of he RBSM tire model was inspected the fact in agreement with the chart. And we calculated static and treading states by using the RBSM tire model and clarified a part of fundamental deformation of a tire.

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Vibration level (VL) is often used as an evaluation index for intensity of blast vibration on site. However, VL does not indicate an actual wave form of vibration velocity. VL is estimated by peak particle velocity (PPV) obtained from measurements of vibration acceleration, in depending on a relative expression between PPV and VL. On the other hand, differences of blasting methods are not taken into consideration for the relative expression. In this paper, the relative expression between PPV and VL is investigated by means of estimating simulations based on the number of overlapping holes. The A-value of the relative expression is proposed according to such factors as the difference of instantaneous detonator, delay detonator, number of blast-hole, blasting pattern and elapsed time in blast.

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Recently, the significance of aesthetic assessment and design about bridges has been recognized. And then it is required to consider a public involving type social capital formation and the user's “Kansei (sensitivity)” in designing of bridges. In this paper, we take up the “Kansei Engineering” which achieves excellent results in the field of developing new products. We tried to form a relationship rationally, between the designing elements for Girder Bridges and “Kansei (sensitivity)”, by doing questionnaires to students and analyzing their “Kansei (sensitivity)”. In addition, we clear the utility of the “Kansei Engineering” method by comparing the the “Kansei Engineering” method with the “Neural Network” method which is used frequently as an effective way of Aesthetic Assessment of Girder Bridges.

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Deformation of earth-retaining walls used in excavations in clayey soil is less when the walls are constructed through ground improvement and strut preloading. At the same time, earth pressure on the backside of the walls is greater than it is when the above methods are not employed. In such cases, the design method cannot incorporate the assumption that the earth pressure on the backside is a known value independent of the displacement of the wall. The use of a calculation method which assumes a ground spring on the backside may be considered, but no method of determining the horizontal subgrade reaction coefficient and minimum earth pressure on the back side has been established. This paper proposes a method to determine the horizontal subgrade reaction coefficient and minimum earth pressure on the basis of a numerical calculation result according to the finite element method. This paper goes on to discuss the results of applying this proposition to two sites: a site with improved ground on the excavation side and one in which the strut preload method was used

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A monitoring method using acoustic diagnosis technique is proposed to improve the management of shield tunneling operation. Relative energy contained in a specific frequency band in power spectrum to the whole energy is used for detecting anomalies in the machine health. The investigation on data sets obtained from two construction sites shows that the signals associated with the anomalies have an energy ratio over 0.4. Moreover, principal component analysis is employed to perform the pattern classification of the signals for detecting the changes in ground conditions. The study shows that the normalized power spectrum is useful for the classification.

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A pipe cooling system is one of the major methods that are used to control thermal stress of concrete structures. In this study, three-dimensional finite element method to consider the heat balance between concrete and water in cooling pipes was used to estimate the effect of controlling thermal cracking by the pipe cooling system stationed three-dimensionally and suitably for the pail of a pier in the cable stayed bridge. Therefore, this theoretical method showed applicability for estimating the effect of control of thermal cracking.

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This paper deals with a simplified method for evaluating the maximum response amplitude of the pedestrian bridges caused by a walking human. Numerical simulations were carried out for the pedestrian bridges with the structural logarithmic decrement δ₁ of 0.01-0.10. It was ascertained that the evaluation value based on the simplified method developed in this paper could be fairly in good agreements with the computed value when a person walked on the bridges with and without the same pace as natural frequency.

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Seismic microzonation maps are very useful materials for prevention of earthquake disaster at a site. It is needed to investigate mesh-size of the map which is appropriate for topographies of small islands like Okinawa prefecture. But larger number of meshes requires the more data of subsurface layers at the site. It seems to be the most probable that there are not enough of the necessary data. This study proposes a practical method, which can supplement shortage of the data, by using statistical analysis for available data on geomorphological land classification and geological survey. Furthermore, based on the supplemented data, a practical formula estimating dynamic physical properties of surface layers in Okinawa prefecture is proposed.

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This research proposes an integrated approach, in which the existing software is used for doing the traditional work on roads and a newly developed dedicated groupware on web is developed for promoting the sharing of the information and the collaboration among the participants in the lifecycle of roads. This paper introduces the groupware and uses the groupware for case studies. This approach is expected to be helpful to improve the efficiency of the sectors through the lifecycle and makes it convenient to do comprehensive analysis such as lifecycle cost analysis.

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This study presents an experimental method and results for the snow melting system, where mountain tunnel spring water is used as heat source. This may prevent running cars from the slip accident at the bridge at exists of the mountain tunnel. In order to find an effective concrete material, several aggregates such as glass fine aggregate are mixed in the concrete. Based on the laboratory test results, the field tests are planned. In the field experiment, snow did not pile up at all even a quantity of snowfall of 29cm/day, when the tunnel spring water of 10°C was used. As the result, the water pipe road heating by means of tunnel spring water was effective as a snow melting system.

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