In order to clarify the mechanism and the criterion of shrinkage cracking of concrete, it is necessary to obtain the data on the relationship between the stress restraining concrete and teh occurrence of cracking. Then, in this research, the new testing apparatus in which the restraint ratio can be kept constant and the stress occurring in concrete can be directly measured was developed. For the verification of performance of the newly developed apparatus, tests for the static direct tensile strength, tensile creep, tensile stress relaxation test and drying shrinkage cracking were carried out. It was found that the newly developed testing apparatus was available as a multipurpose testing apparatus.

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In this paper, we proposed the estimation method of drying shrinkage cracking in the reinforced concrete member by bond analysis. In order to confirm the validity of the estimation method of crack width in RC member by bond analysis considering shrinkage and creep, the restrained cracking specimens laying the reinforcing bar were made, and the strain of reinforcing bar, strain of concrete and crack width were measured. In result, on the whole, good agreement was shown between the analytical results value and the experimental results.

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Relations between defects in self-leveling material and surface quality of concrete slab were experimentally examined. A defect occurrence situation was changed greatly by condition of slab surface. Then, situations were classified into three kinds, "No defect", "Separation" and "Crack". Moreover, it became clear that defect occurrence situation can be predicted by amount of surface moisture and volume of micro voids. Then, when cracks may be occur, amount of cracks can be predicted by surface strength. Those measurements can be easily done in actual construction sites. Therefore, this defect prediction method greatly contributes to performance gain of floors.

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In this study, stresses and strains of mortar and coarse aggregate in high strength concrete under compressive stress condition were estimated based on stress-strain curves of concrete, mortar, and coarse aggregate, and the destruction mechanism of high strength concrete was examined. The results indicated that the destruction of high strength concrete is caused in the stress of mortar becoming near its compressive strength when compressive strength of coarse aggregate is higher more enough than that of mortar, and that the average strain of mortar when concrete made using coarse aggregate with high Young's modulus is destroyed is small.

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To design the mitigation method for efflorescence of historical brick masonry buildings reinforced with concrete, the flowchart for mitigating efflorescence was proposed and the efflorescence risk of actual brick masonry building was estimated by using proposed flowchart. Concretely, features on the wall, environmental conditions were grasped, and numerical simulation of water movement was performed. As a result, heavy efflorescence was observed on the part considered efflorescence risk would be high. In addition, mitigation method of efflorescence was proposed and the effect was verified by accelerated test using model wall specimen. It was considered that efflorescence could be mitigated by constructing reliable insulation layer of moisture between brick masonry wall and reinforced concrete.

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This paper shows a deterioration model due to chloride attack in consideration of uncertainty to estimate the initiation and the rate of corrosion, and to analyze the structural capacity, i.e. shear capacity and bending strength of beams and columns with corroded reinforcing bars based on simple formulas formed through the past experiments. Then, the failure probability and the deterioration risk of deteriorated members due to earthquake can be evaluated by probabilistic method. By applying genetic algorithm to minimization of life-cycle cost including the deterioration risk, the optimal maintenance plan of reinforced concrete buildings can be found and case study is finally conducted to prove this system.

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This paper describes analytical results by a boundary element method on stress singular conditions at the interface edges between the concrete bodies and cemeticious adhesive mortar with ceramic tiles. A general stress function is also presented that uses two singularity parameters to predict shear stresses near the stress singular points by a fracture mechanical method. Several new methods are presented to obtain the values of two parameters which are stress intensity factors and singularity exponents. Furthermore, the usefulness of these methods and the characteristics of the two parameters under different influences of several kinds of finishing conditions are discussed.

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This paper describes the rational evaluation of foundation input motion (FIM) in "Response and Limit Strength Calculation (RLSC)", which is developed as the performance-based design in Japan. In RLSC, an effect of input loss caused by embedding foundation is calculated using amplification of surface strata Gs and coefficient of soil-structure interaction (SSI) β'. It is pointed out that the evaluation of the embedding effect of foundation in RLSC is conservative, particularly in a short period range less than the first period of surface soil. This is because only coefficient of SSI β' considered first vibration mode of surface soil. To improve this overestimate of FIM, coefficient of SSI β' considering second vibration mode of surface soil is incorporated and a new formula is proposed. To verify the accuracy of FIM by a proposed method, we carried out an axisymmetric finite element method analysis (AX-FEM). Response acceleration spectra by the proposed method are good agreement with that of AX-FEM.

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High-tension cable nets are, owing to strong pre-stressing, stiff enough to be used in structural and architectural engineering practice. In contrast ot these high-tension nets, low-tensioned or extremely flexible nets, such as sports nets, spider nets, hammocks, fish and mosquito nets, are usually not for engineering purposes. Therefore, thesefrexible nets have been so far not frequently treated in structural engineering. The no-compression material property and extreme frexibility of nylon or polyester nets present, however, academically interesting issues from the viewpoint of structural analysis and computational mechanics. At the beginning of equilibrium iteration, for example, no initial stiffiness may be expected and net segments may also show sags and slackness in the deformed configuration. Only a few experimental and analytical works are available on this particular type of nets. In the present study, loading tests are carried out on extremely flexible nets and the experimental results are compared to those by an effective computational model for varification. The eigenanalysis of free vibration is also useful to compare the hexagon and rectangular mesh nets from the aspects of eigenvectors.

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The great earthquake in 1978 caused severe damages to buildings and infrastructures in Japan. On a basis of the lesson learned from the damages, the Japanese Building Standard Act was revised in 1981. Being insufficient seismic capacities of those buildings built before 1981, it is politically encouraged to improve structural properties which are specified stiffness, strength and ductility. We performed the lateral loads test of a frame specimen retrofitted by steel brace without anchors to confirm the effect of the seismic retrofit. And the frame specimens were modeled, the finite element analyses were performed and grasped the relationship between story shear force and story displacement, the failure behavior and stress distribution of the model in detail. The results of analyses were suited the tests approximately, we proposed the resistant mechanism to shear force transfer of seismic strengthened RC frames with steel brace considered the grout stress.

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A frequency-domain method is developed for evaluating the earthquake input energy to two building structures connected by viscous or viscoelastic dampers. It is shown that the earthquake input energies to respective building structures and added viscous connecting dampers can be defined as works done by the boundary forces between the subsystems on their corresponding displacements. It is demonstrated that the proposed energy transfer function is very useful for clearer understanding of dependence of energy consumption ratios in respective buildings and connecting viscous danpers on their properties. it is concluded that, owing to the property of the energy transfer functions, the total input energy to the overall system including both buildings and connecting viscous dampers is approximately constant regardless of the quantity of connecting viscous or viscoelastic dampers. This property leads to an advantageous feature that, if the energy consumption in the connecting viscous dampers increases, the input energies to the buildings can be reduced drastically.

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Two methods of reducing a single-story asymmetric building under uni-directional earthquake motion to the equivalent single degree of freedom (ESDOF) system, the static and dynamic methods, had been proposed by the authors to improve the capacity spectrum method used in the calculation of response and limit strength provided in the Building Standard Law Enforcement Order of Japan. Both methods are extended to apply for multi-story asymmetric buildings in this paper. For four types of 4 story RC buildings with different eccentricity by arranging multi-story shear walls, the validity of the methods is examined with the earthquake response characteristics of the ESDOF system. An evaluation method of the earthquake response for multi-sotry asymmetric buildings considering the higher mode effect is also proposed.

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This paper discusses seismic casualty from the point of view of a probability model based on binomial distribution compared with the actual data of hearing investigation into the 2003 Tokachi-oki earthquake and the 2004 Niigata-ken Chuetsu earthquake. The parameters of the model are the decrease rate of floor space by furniture falling and the number of people in that space. It is possible to estimate the occurrence probability of casualty using the model. Moreover, we propose a simplified method of evaluation of a casualty potential by furniture density as an application of the model. The furniture density is the number of furniture per the floor space. This index is extremely easy so that anyone can calculate the casualty risk of their bedroom, living room, and even their house.

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An experimental study on the integrated health monitoring of cast-in-situ concrete pile foundations is presented using vibration and wave measurements. The health monitoring strategy is a two-stage damage detection scheme before and after excavation as in the case of the previous paper. A series of cyclic loading tests on cantilever-type specimens of cast-in-situ concrete pile have been performed to simulate the development of seismic damage. Four damage detection tests, i.e., vibration generator, impact hammer, acoustic emission and ultrasonic wave tests have been carried out during and after successive loading cycles. Based on the experimental results, the usefulness and limitations of the proposed damage detection scheme are discussed for cast-in-situ concrete pile foundations.

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It is important to estimate the seismic behavior of the surface soil layer to calculate the input earthquake motion to the building because the surface layer amplifies the motion. It is also known that the soil damping depends both frequency and strain, and the damping is considered as the sum of the hysteretic damping and the scattering damping. There were many investigations to propose the calculation method considering both dependencies, but practical methods were few. The author studies the nonlinear analysis considering both dependencies. In this paper, the time history nonlinear ground response analysis method using the causal models for both the hysteretic damping and the scattering damping was proposed. The basic characteristics of the proposed method were studied using the 1 DOF model and the validity of the method was confirmed.

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In this paper, a shape optimization method for shell structures is shown. The present method is based on the traction method proposed by Azegami. However, the algorithm of the present method is very simple in comparison with the original method. The sensitivity analysis is not need in the present method. The method is similar to large displacement analysis based on update Lagrange, and it is named "deformation method" in this paper. The reliability of the present methods is shown by comparing with the original traction method and other shape optimization methods. Several examples are shown to demonstrate the effectiveness of the present methods for shell structures.

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In the excavation work on soft ground, the soil improvement method by quicklime piles is likely to be employed in order to obtain the safety of the earth retaining structure. Due to the driving of the quicklime piles, the adjacent ground is moved horizontally and vertically. Sometimes the ground movement during soil improvement work damages to adjacent ground facilities. In this paper, based on the measured ground displacement in detail, the prediction method of the ground movement and the prevention method of the ground movement are presented.

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Most of papers and reports on concrete structure member deformation characteristic affected by Alkali-silica reaction are mainly carrying out at indoor. No report of measurement of deformation behavior that actual structure is measured by long-term observation is available. This paper reports deformation behavior of actual structure due to aging phenomena by observations for long-term period, such as cracks, expansion rate and status of progress. They are emerged as a result of examinations of an actual structure affected by Alkali-silica reaction; the development effecting by Alkali-silica reaction is implicated by temperature condition, external constraint condition of the structure. Mechanical characteristics of concrete such as elasticity coefficient have reduced as same as existing report. Development of cracks has been same tendency as expansion rate, however prediction of expansion rate for actual structure by summarization of cracks tendency is difficult.

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In order to study the natural period and the damping factor of conventional wooden-framed houses, and to consider the possibility of applying microtremor measurement to seismic diagnosis, we investigated 238 two-storied houses, and analyzed the results based on shaking table tests using9 full-scale models. Major findings are as follows: 1) As the housing becomes newer, the natural period becomes shorter, and the damping factor and the evaluation of seismic diagnosis become higher. 2) The natural period becomes shorter in accordance with construction stage, and the stiffness of completed house is about four times greater than that of the framework with bracing members and bearing walls. 3) The elastic period obtained by the sweep vibration tests, whose input acceleration values are from 25 to 30 gals, has a relation to the natural period. 4) The natural period based on microtremor measurement is not sufficient to estimate the evaluation of seismic diagnosis. 5) As the stiffness obtained by seismic diagnosis does not correlate closely with that obtained by microtremor measurement, it would be difficult to estimate the stiffness of seismic diagnosis from microtremor measurement.

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To improve the seismic performance of existing urban traditional wooden houses, the seismic reinforcement design method is explored. From the structural observation of thirty traditional wooden houses so-called Kyo-machiya, their seismic performances were evaluated based on the response-limit capacity analysis. The result indicates that many Kyo-machiyas need the seismic reinforcement. Their seismic performances and seismic reinforcements are examined statistically. As an example, the seismic reinforcement design method for one typical Kyo-machiya is shown in detail. It is found that the proposed design method can improve the seismic performance of Kyo-machiya both in horizontal and vertical views by arranging appropriately seismic elements.

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The main objective of this study is to define hysteretic model for deterministic nonlinear time-history analyses of Japanese conventional wood houses under various earthquake ground motion. Three hysteretic models are used to fit cyclic loading tests of walls. Their models are combination of elasto-plastic and slip model, Takeda model for reinforce concrete beam member and Magara model defined based on cyclic tests of wooden shear walls. Their applicability is confirmed from the comparison to pseudo dynamic tests. The maximum response is estimated within a range of twenty percent difference on every hysteretic model. Due to several cyclic loading, ductility is decreased in bracing wall therefore the maximum responses of bracing walls are overestimated. Residual displacements are not followed by every hysteretic model. The parameters of simple combination of elasto-plastic and slip model are proposed based on the structural design values and results of fitting of cyclic loading tests. The proposed model almost corresponds to the fitting model.

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Measure on long-term compressive properties of reinforced concrete columns using high strength concrete were carried out. Two actual columns in a 45-story building has been measured for about two years after casting. Additionally, one-third-scale columns under step-by-step incremental loading, simulating actual stress condition in consideration of construction process were also measured for about three years. The compressive creep model for high strength concrete, which is modified using CEB-FIP model code 1990, was proposed for the prediction of the compressive performance of these columns.

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Objectives of this study were to propose evaluating method of axial load carrying capacities of R/C columns after shear failure using experimental data reported in the previous paper. For this purpose two criteria were examined, i.e. Mohr-Coulomb criterion and slip criterion between shear crack surfaces considering friction. Effects of confinement given by various hoop reinforcing details were specially paid attention. Two assumptions were used, i.e. i)the cohesive stress was degraded due to damage of core concrete and ii)confining stress by hoop reinforcement was degraded due to damage of reinforcement depending on the details. Finally evaluating equations of maximum deflection angles of shear failing columns experienced before losing their axial load carrying capacities were propose according to two assumptions mentioned above.

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A RC flat beam allows considerable latitude in building if the beam and a normal column can be used in rigid frame construction. There are some fears about RC flat beam and column joint system, whether stress can be transmitted well between the beam and the column, whether bond of longitudinal bars of the column is sufficient in beam-column joint. Additional reinforcements to strengthen beam end, which shifted plastic hinge of the beam at a distance from column surface, more lateral confinements in connection, and spliced lapping bars of column at joint were adopted. Seven RC flat beam and column joint specimens were prepared for cyclic loading tests to examine above measures. As results, it can be said that RC flat beam and column joint system is possible.

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Preserved compressive stress in concrete composite beam due to loading itself-weight on the PCa under construction works as the same reinforcement stress as prestress, and it is available to be optimal designs for concrete composite beams that choosing reinforcements between prestressing steels and steel bars balances their performances and costs. Analysis of mechanical properties of four models of concrete composite beams on Reinforced Concrete, Prestressed Reincorced Concrete and Prestressed Concrete Structures leads to the best field of prestressing rate for the designs of the beams, that is 0.5 rate. Because the preserved compressive stress works very effectively as reinforcement in this field than in the others. And concrete composite beams in this field are possible to be the most balanced ones between performance and cost.

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Concrete filled steel tubes (CFT) are widely used in Japan as beam-columns for high-rise building frames because of the high stiffness, strength and deformability in comparison with the other structural members such as shaped-steel sections or vacant steel tubular sections. In this study, a CFT member with a pre-tensioned steel wire is proposed. In the member, an asphalt thin layer is placed on between steel tube and filled concrete, so that the no bond effect between those is expected. A pre-tensioned steel wire si placed at the center of a CFT section, which introduces the compressive pre-stress into the filled concrete. The bending test has been done, where the vertical load applies monotonically at the mid span of a simple supported beam composed of a CFT member with steel wire. The test parameters are (1) the diameter-to-thickness ratio (Dlt); and (2) the ratio of the pretension force to the axial strength of CFT section. The test revealed that the strength increased when the proper pre-tension force was introduced; the elastic flexural stiffness of the member was adequately evaluated by a simple summation of the concrete stiffness and the steel tube stiffness; and the prediction formulae specified in the present Japanese codes under-estimated or over-estimated by Dlt both the yield strength and the maximum strength of the specimen. Therefore, new strength prediction formulae have been proposed based on the test results.

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Structural design review systems in various regions of the United States were investigated by directly asking questions to 57 experts of structural design including structural engineers, academic researchers and building officials. Answers from 18 of these experts were obtained and based on their responses details of the structural design review systems were studied including design review by building authorities, peer review and their relationships. There are four notable findings: (i) There are significant differences in structural review systems between different states or jurisdictions. (ii) The design review systems answered in the questionnaire can be categorized into four groups represented by West coast, city of Chicago, state of Massachusetts, and New York City. (iii) The peer review system, which is well-known as an effective design review system among building experts and owners, is utilized in most states, although with different styles of application. (iv) Engineers of record always take the ultimate responsibility of the structural design and there is no responsibility on peer reviewers or building authorities.

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