Estimation method for the stiffness of practical strucrures based on mesured deflection is proposed. In this paper, as examples, bridge girder stiffness is estimated from deflection which are measured during placing of the slab concrete, and after construction, are obtained by loading test. And degree of composite action between the girders and the slab concrete of noncomposite girders is estimated from deflection of girder. When girder stiffness in accordance with practical behaviour is evaluated, we can present a more rational and reliable model of analysis and design.

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The theoretical and numerical method on the underpinning ploblem, one of the temporary supporting systems, is studied in this paper.
The theoretical explanation by using the matrix analysis method is introduced and applied to the supporting problem temporaily loaded on the pile foundation consisting of grouppiles.
This method is characterized by using the calculated results of F. E. M. as the displacement property of foundation.
In addition, some examples of underpinning by using this numeric method are analyzed and studied compared with the measured results of above examples.

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Rock mass classification applied to a tunnel face under construction is composed of the engineering and geological factors of the rocks. Unfortunately, many of the classification factors are qualitatively described. At the present stage, an engineer's subjective judgments play an important role in rock evaluation. The present study aims to show the details of the above subjective system. Much of the data used to evaluate the rocks under construction are documents, sketches and so forth. In this study, questionnaires using the above qualitative data are distributed among experienced engineers. Results of these questionnaires are collected and analyzed by using the fuzzy sets theory. By numerical examples, we make empirical factors and the manner of decision making of an engineer clear.

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For braced excavation where the thickness of a soft clay layer is large, the stability of ground under the excavated bottom is important. In order to study the role of the sheet pile under the bottom to the stability, the present design methods are reviewed and the finite element analysis (FEM) is performed in which the ground is assumed to be a Mohr-Coulomb elasto-plastic model. The results from the FEM analysis are compared with those from the present design methods. It turned out that the length of sheet pile derived from the present design procedures is long enough from the theoretical view point. However, uncertainties remain in the determination of the shear strength of the ground for the excavations.

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A new corrosion prevention method for splash and tidal zone of steel piers has been developed by using titanium clad steel sheet. Shear strength value of joining interface of titanium clad steel sheet is higher level than that of laminated steel sheet or adhesive interface. Shear fatigue limit of joining interface exceed the estimated strength value due to thermal expansion. TIG welding method is recommended for mounting the titanium clad steel sheet to steel piers. For procedure of butt welding method, it is recommended that, at first the base metal is welded to mount to steel piers and overlay welded in the groove, and next, titanium sheet is welded to cover metal of titanium clad steel sheet at the corner for covering the welding zone of base metal.

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A new corrosion prevention method for splash and tidal zone of steel piers has been developed by using titanium clad steel sheet. The design life of the Trans-Tokyo Bay highway is required at least 50 years, therefore, corrosion protection is essential for the steel piers under marine environment. Although splash and tidal zone is most corrosive and hard to repair, conventional methods are not reliable as for long term durability. On the other hand, titanium is expected to be a perfect corrosion resistant material under marine environment, and application method of titanium as corrosion prevention was investigated. This paper reports the results of experiments on corrosion prevention performance of this method, especially on prevention of galvanic corrosion between titanium and steel both in the laboratory and in the marine environment.

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It is the best way of measuring a body two dimensionally to measure it directly using steel tapes when the shape of it is simple enough, but this method is not applicable when the shape of the target is complicated. In this case, a measuring method of touching type which is performed using magnescale, is usually adopted. This method needs a lot of manpower and furthermore has a defect of being fragile against mechanical shocks.
The authors have developed an efficient two dimensional measurement system using a CCD camera which solved almost all of the problems the traditional methods carry with. This system has already been made practical use in the process of measuring a large size members of steel structures in a manufacturing shop. This paper presents the principle of this system and the way of calibration as well as several illustrations.

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This paper describes a case record of improving design of a steel sheetpile cellular bulkhead with deep embedment depth into soft clay ground, which is to be improved by sand compaction piles. Behavior of the originally designed bulkhead was investigated by means of numerical analysis. Result of this investigation suggested more advantageous design specfication of the structure itself and the soil improvement. In order to verify this result, jack loading tests and back-filling loading tests were carried out on two full-size cellular bulkheads, corresponding to the original design and improved design. Observed behaviors of the bulkheads compared well with results of the numerical analysis. In the loading test. the bulkheads showed a rocking pattern instead of shear deformation. This result proved that the improved design restored the originaly proposed function of structure.

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The influence of the electric wires on the supporting poles during earthquakes was investingated by the analysis based on the lumped mass model.
The results indicated that the dynamic coupling of the wire and the pole in terms of the nonlinear restraining force imposed on the pole is dominant, and the effect of the vibration of the wire itself is negligible. The degree of the restraining effect is varied in the ground conditions supporting the neighboring poles and so on.
Comparison of these results with that of the single pole without wires indicated that the possible seismic damages in the combined pole and wire system is reasonably predicted by the analysis of the single pole supported on the loose sand or concrete base except for a rare type of the damages by the shear failure in the joint of the anchoring cable.

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It goes without saying that the frequency and degree of frost damage strongly depends upon climatic conditions. In this investigation, a survey of the frost damage of concrete used in road bridges was made and the degree of damage was classified in accordance with the state and area of damage observed. The relation between this degree of damage and climatic conditions shows that the degree of damage is related not only to the number of freezing and thawing but also to the degree of saturation due to rainfall and snowfall during winter. It is necessary in designing concrete structure to take into consideration these climatic conditions for preventing frost damage. The adequate evaluating method of these climatic conditions is shown here.

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This paper proposes a practical monitoring method of concrete placing, from out side of the forms, using an infrared radiometer and distinguishing the discrepancies of temperature at the surface of the forms. With the help of the experimental results the height of the casting concrete can be shown easily, and the defects of concrete, caused by poor consolidation, such as voids and honeycombs, can also be detected clealy. The minimum discrepancies in temperature required between concrete and forms for detection is above 0.14°C. Time required for detection may differ according to the type of the forms, discrepancies in temperature between concrete and forms and the conditions at the time of measurement. By the help of the apparatus, used in this experiment, the average delay in time required to record the rise of concrete level is 20 seconds for metal forms and 100 seconds for plywood forms.

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Slurry walls have till now been used largely in temporary structures in the construction of retaining walls and underground water screens. But as a result of recent developments in concrete and in the field of excavation equipments it has become possible to construct very deep slurry walls. However, this necessitates development of improved methods of quality control and high strength slurry wall concrete.
This paper describes the research undertaken to study the feasibility of constructing a 2.8m thick and 135m deep slurry wall to serve as a water screen and retaining wall in the artificial island in the Trans-Tokyo Bay Highway project.
To begin with, laboratory studies were carried out to determine the mix proportion of the concrete for adequate flowability, segregation resistance and compressive strength. The results obtained from the laboratory tests were verified in a full scale field test.

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In this report the crack evaluation system for analyzing the condition of superannuated tunnels is discussed. This system is based on analysis of continuous image recording of tunnel walls. The system is characterized as follows:
1) It enables quick and objective investigation;
2) Personal computer are adequate for the image recording, processing, and analysis;
3) It aims to provide for the structuring of an expert system for finding causes of deformation.
In applications of the system we found that analysis of crack elements was useful in finding the causes of deformation.

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The Sydney Harbour Tunnel is being constructed using the immersed tube (IMT) method to solve Sydney's cross-harbour traffic problem. Since there was no suitable site for construction of the IMT units around Sydney Harbour, they were constructed at Port Kembla, about 70km south of Sydney, and towed through the open sea to the tunnel site. As IMT units of rectangular concrete section, as used for the Sydney Harbour Tunnel, had previously been towed only short distances in sheltered waters, this was the first experience of such long ocean towing. This paper reports on the background of the ocean towing, the behaviour of the IMT units during towing (external loads, strength, stability, motion, towing force etc.) and on details of the towing operation.

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