This paper proposes a new type of structure, the slab-truss structure, in which precast slabs and truss-shaped web members using high-strength concrete are joined in such a way as to avoid the occurrence of secondary stresses due to prestressing. The mechanical properties of the resulting structure were ascertained by performing loading tests on large-scale models, and on the shear transmission mechanism. Design comparisons with conventional structures showed that the structure proposed here is a rational one, and of practical benefit in reducing the weight of prestressed concrete bridges.

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This paper is aimed to propose analytical method to predict time and accumulative dissipated energy of reinforced concrete beams till complete failure under cyclic large deformations. The calculated total dissipated energy, up to failure, shows almost same in spite of different amplitudes and is in accordance with experimental results. This method for calculating is shown to be reasonable.
Based on the analytical method, total dissipated energy is introduced as index for accumulative damage. Accumulative damage is evaluated by using the index for reinforced concrete beams subjected to random waves. The index is used for reinforced concrete beams and the accumulative damage is in accordance with experimental results.

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Deterioration of concrete structures has been drawing a greater social attention. Severe chloride-induced damages have been observed in seaside area. The deterioration is mainly caused by corrosion of reinforcements due to the action of chloride ion. This paper develops a procedure to determine design concrete cover for a deterioration due to chloride attack. Statistic method to seek design concrete cover is developed by using the stochastic parameters that contributes to structural damages. These stochastic parameters are obtained from data analysis conducted on the survey of actual structures and laboratory tests. This analysis is useful for durability design and rehabilitation planning during its service life.

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It was investigated in this paper that the properties of the concrete using GROUND GRANULATED BLAST FURNACE SLAG in order to improve durabilities of RC Segment Concrete for the sheild tunnel in Trans-Tokyo Bay Highway.
The investigated properties are as follows, durability for sea water, diffusion of NaCl, permeability, and the relation between compacting condition at casting and cracking of concrete, GROUND GRANULATED BLAST FURNACE SLAG is effective material to improving of durability in concrete segment.

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The objective of this research is to establish the test method for self-compactability of fresh concrete, which is inevitable in mix design and manufacturing of self-compactable concrete. The V-type funnel test is proposed for evaluating the flowability through small openings, which is one of the most important properties of self-compactable concrete. It is experimentally verified that self-compactability of fresh concrete placed for usual arrangement of reignforcement in the formwork can be evaluated by deformability obtained from slump-flow test and flowability through small openings obtained from V-type funnel test.

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Some high absorption polymer with water have characteristics of discharging water when they are mixed in cement paste and being frozen without each particle combined below the freezing point. In this study, some basic properties of concrete mixed with this high absorption polymer absorbed mixing water, which was cooled by liquid nitrogen, in order to clarify to be applicable to precooling method were investigated. The results show that slump, air and strength of concrete mixed with high absorption polymer are roughly as same as conventional concrete and it can be largely reduced temperature of mixed concrete by using cooled high absorption polymer.

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The finite element analysis is performed on reinforced concrete beams and the nonlinear behavior is investigated in detail with consideration of stability. The results show that the failure of RC beams is closely related to the bifurcation point and that the failure is understood on the bifurcation path after the bifurcation point is obtained analytically. In the paper, the post-peak and the ultimate behaviors of RC beams are expressed by analytical calculation.

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Main object of this study is to estimate the shape effects of internal hoops on ultimate capacity of the R/C column under biaxial bending. Nine specimens, each 300mm square by 1, 000mm high, containing either 8 or 12 longitudinal steel bars and different arrangements of square or octagonal steel hoops, were tested under uniaxial or biaxial eccentric loads.
From the results of the test and analysis, it is found that the analytical values calculated by Element Division Method agree well with that of experiments, and the formula proposed by Kent & Park is the most applicable to estimate the ultimate strength and ductility for biaxial bending.

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The moisture transfer within concrete due to drying was analyzed by non-linear diffusion equation. The complete procedure of the analysis was established by the comparison of the numerical results with experimental ones concerning wide range of mix proportions of concrete. The variation of the coefficients needed to the analysis were also presented related to wide range of water cement ratios and some characteristics of the coefficients are discussed based on the numerical results. In addition, the effect of evaporation heat loss on water transfer was considered by the analysis of a simultaneous heat and moisture transfer. As a result, it is shown that the effect is negligibly small as for the drying in room temperature and humidity.

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This paper describes an application of the System Identification (SI) method to damage detection for deteriorated concrete bridges based on modal parameters estimated from dynamic loading tests. In this method, a new idea for a damage model considering the non-proportional damping as a parameter of the damping ratio which can be coupled with the decrease of stiffness by a statistical analysis of accumulated data for existing bridges, was studied. Furthermore, a method for estimation of initial values for variables to be identified in the SI method is proposed and the feasibility of this method is verified based on an actual bridge data.

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In this study, new method of evaluation of damage index of reinforced concrete member of which ultimate limit state is reached by flexural-compression after yielding is proposed. Accumulative consumed energy of member is thought to be a total energy consumed during earthquake motion. While, maximum consumed energy is a specific value for each member and is determined by the dimension of section and material properties. Proposed damage index is examined by available test data.
Furthermore, we show the procedure for applying proposed damage index to seismic design of reinforced concrete structure in the lignt of reliability approach.

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The new evaluation for pavement cracks by fractal was proposed by the authors before. The spatial variation of the pavement profiles is evaluated with the fractional Brownian function characterized by fractal dimension. The spatial variation for real pavement had been observed for five years. The observed fractal dimensions of the pavement profiles were increasing every year and correlated with the standard deviation of the vertical displacement very well. The fractal dimension of the profiles can be also applied to the travel comfort. We would like to propose this new parameter, a fractal dimension, as a pavement serviceability index.

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With request for larger RC structures and structural members in these days, longitudinal reinforcing bars are required to be large in size and to be placed in multi-layers in the cross scetion of members. This trend makes it nacessary to examine the applicability of present code equations for flexural crack widths of RC beams. Based on the experimental test results, it is discussed in this paper how the multi layers of longitudinal bars influence the flexural cracking of RC beams. Special attention is paid to how the location and the size of bars as well as the bounded bars influence the cracking behaviors. The test results show that the crack spacings and the crack widths of beams depend upon how the longitudinal bars are placed although the bars nearest to the concrete surface have dominant effects on cracking.

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There have been developed several equations for estimating the flexural crack widths of RC beams, and some of them are now appreciated in code specifications. Since most of them are semi-empirical, their applicability should be examined whenever new types of structure come into consideration. One of the recent requirements for RC structures is to make them larger in size. As for the reinforcing bars, placement of bars in multi-layers in the cross section as well as usage of large sized bars is indispensable for design of large sized beams. This paper discussed firstly the applicability of present equations for flexural crack widths to the beams with multi-layers of longitudinal bars. The examination of applicability is extended using test results of 86 beam specimens which are deliberately selected so as to represent wide variety of arrangement of reinforcing bars. Based on the discussion the authors propose the equations for crack spacing and crack width with wide applicability.

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The analytical method to evaluate the diagonal shear failure strength of RC beam was developed, in which the modified compression fields theory was extended. The effects on the shear strength of effective depth, longitudinal reinforcement ratio, stiffness of longitudinal reinforcement and concrete strength were investigated analytically.
Using the proposed tension softening relation, size effect in the shear strength can be evaluated satisfactorily by the analysis.

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In order to utilize Glass, Aramid and Carbon fibers as a reinforced material of concrete, alkali-resistance of each fiber was tested and computational model predicting the degragation of fiber was verified based on the experiments for alkali-resistance of fibers. Alkali-resistance of each fiber was compared from the view point of fracture strength and Young's modulus through the accelerated aging test in the alkaline solution. In addition, the degree of degradation of each fiber after aging test was investigated by Scanning Electron Microscope.
As a result, it was concluded: (1) Glass fiber was easily degradated in the alkaline solution and the progress of degradation was simulated quantitatively by the proposed method based on a diffusion theory, (2) both Aramid and Carbon fiber had a significant alkali-resistance without degragating.

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