This paper is intended to study the relationship between the flexural strength or the shrinkage ratio and the curing method or the mixing proportions of the concrete, were influenced such as the admixture, kinds of the cements and the aggregates. As the results, it was found that the concrete have the high flexural strength and the small shrinkage ratio when they were mixed with the silica fume and cured in 60℃ hot water about 6 days. And especially, it was found that the concrete have very high flexural strength and low shrinkage ratio when the cement included more than 0.35% of Na_2O, when the sand-aggregate ratio was more than 60% or when the sand-cement ratio was about 1.6.

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A new test method for shear fatigue for building sealant is described. There was the shortcoming such as unexpected crack initiation from bead ends in parallel type specimens used for present fatigue test. To avoid the unexpected failure during a shear test, a ring type specimen of not having bead ends was proposed and a fatigue test apparatus for the specimen was developed. Shear fatigue tests by the new method were carried out for the specimens with various kinds of cross sectional shapes. The data of shear fatigue resistance of sealants were successfully obtained without the unexpected failure and the effect of cross sectional shape was discussed.

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It is known that fail-safe structures which have redundant subsystems can exhibit stable seismic resistance against earthquakes with unknown predominant periods. In this paper, effects of phase characteristics of ground motions on the seismic resistance of the fail-safe structures are investigated using numerically simulated ground motions with various phase characteristics. The phase characteristics are represented by maximum instantaneous energy input and change of predominant period in time domain. It is observed that the fail-safe structure has less seismic resistance than single structures when the predominant period changes from a shorter period to a longer period in time domain and the maximum instantaneous energy input is large. In the worst case when an accelerograms has shorter period components in the first half and longer period components in the latter half, seismic resistance of the fail-safe structure is about 0.7 times those of single structures. A method of estimating such effects of phase characteristics is proposed on the bases of energy input time history, which gives a fairly good prediction to precise responses obtained from dynamic analysis. Effects of phase characteristics of real ground motions are also investigated using recorded accelerograms of the 1995 Hyogoken-nanbu earthquake, however, no clear effects on the seismic resistance of the fail-safe structures are observed.

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This study was carried out to clarify the effects to floor slabs carrying unevenly distributed load and to define design live load tolerance level. Load effect due to unevenly distributed load is expressed by a coefficient of maldistribution. A value was calculated for floor slabs for a long side to short side ratio of one to four. The coefficient is affected by floor slab shape, level of maldistribution, floor slab area, and so on. Moreover, the state of the live load on the floor slab was defined for an extreme or emergency situation. The coefficient of maldistribution under these states was calculated and clarified for various positions. The effects of unevenly distributed load will clarify the design live load's tolerance level, and will be felt by the building user.

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During a strong earthquake, the response of a structure with bilinear restoring force has discontinuity in jerk. In this paper, the method to estimate the ductility factor by the wavelet analysis of absolute acceleration response is proposed. It is found that the wavelet coefficient obtained by wavelet analysis of acceleration response is proportional to the velocity at yield point and the ductility factor is evaluated from the velocity at yield point by the energy conservation law. Using the proposed method, the ductility factor is estimated from wavelet coefficient with good accuracy and its applicability is verified through some simulations.

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This report describes the static and dynamic characteristics of the friction damper with coned disc springs for base-isolation system. The friction damper is constructed by keeping coned disc springs against a horrizontally placed stainless steel plate on the sliding surface by making use of the rebound from deformation of vertical compression. The friction damper has not only damping mechanism but also a function that it supports a part of upper structural load and a fail-safe function. These characteristics were verified by shaking table tests and analyses of base-isolated model using the friction dampers with coned disc springs and laminated rubber bearings.

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The exact prediction of critical points on the equilibrium path is desired in the numerical analysis of critical behavior of a structure. A new strategy for predicting the critical point is proposed here by applying the incremental perturbation method to eigenvalue problem. The variations in eigenvalues are evaluated by solving the ordered perturbation equations successively. The perturbation equations can be solved by applying the generalized inverse. The solution of algebraic equation, which sets the each eigenvalue to zero with respect to incremental parameter, gives the step length to the critical point. Two typical examples for critical behavior show that the strategy proposed here can predict the critical point of structure model with high accuracy.

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In this paper, a method of settlement analysis for buildings with mat foundation is described by considering the rebound of the ground. Generally the ground rebound and the settlement are caused by the excavation and the weight of structure, respectively. To estimate them, it is necessary to take hold of the variation of the excess pore water pressure in the clay layer by the time elapsed and to analyze the interaction between the ground and structure. We presented the relative expression between the mean consolidated pressure, and the coefficient of volume compressibility mv and the coefficient of consolidation cv based on the results of the cyclic consolidation test. And we calculated the rebound and the settlement of the building with basement by the excess pore water pressure obtained from mv and cv. By these results, we obtained that the properties of the ground settlement were changed from excavation period and starting time of the construction of the building and effected largely by the rebound of the ground.

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Generally, bearing plate resistance body for the ground anchor is the single unit style. Therefore, when the resistance body is subjected to large displacement, it can be estimated that the uplift bearing capacity is not demonstrated sufficiently due to the clearance, which appears in the downward of the resistance body. The soil around the resistance body becomes loose so that the soil goes into the clearance. We developed a new composite-type resistance body in order to supplement the deficiency of the unit-type resistance body. The laboratory uplift tests of these resistance bodies were carried out in sand. Furthermore, the field uplift tests were carried out in cohesion soil, too. In this paper, we describe these test results and properties of bearing pressure type of resistance body.

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"SHIRASU" is a volcanic deposit and is distributed widely in South Kyushu. The natural deposits on plains of cities such as Kagoshima are transported by running water, therefore composed of the components of the "SHIRASU", and are called a alluvial "SHIRASU" soil, According to our experience, the piles in the alluvial "SHIRASU" soils show special characteristics in skin friction (shaft resistance). The skin friction of the piles was obtained from the results of the experiments of loading tests on the piles in the alluvial "SHIRASU" soil, and was compared with the results of the calculation by the architectural code for the foundation design. The results show that the skin friction of the piles in the alluvial "SHIRASU" soils is greater than the calculated value by the architectural code. Further, it is shown that the skin friction can be estimated from the N-values of standard penetration test.

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A series of model tests is performed to estimate the load-settlement behavior under static loading condition by a quasi-static loading test using a spring at pile head. In the experiment, a closed-ended steel pipe of 41 mm diameter, three kinds of coil springs and five kinds of drop hammers are used. The effects of elastic wave propagation in the pile can be eliminated in quasi-static test because the loading duration in quasi-static test is longer than in dynamic test. It is recommended the usage of a relatively rigid spring to obtain the load settlement curve that agrees well to those of static tests until large settlement.

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Single-layer lattice shells composed of identical units are light and have simple joints compared with double-layer lattice shells. Their bending stiffness, however, is low and then buckling sometimes becomes a serious problem. In order to improve this drawback, we propose a hybrid single-layer lattice shell combined with supplementary parts. In the paper, structural characteristics such as displacement distributions and buckling loads of EP single-layer lattice shells and hybrid single-layer lattice shells are presented. And, we suggest a design method to obtain higher buckling load of hybrid single-layer lattice shells.

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The dynamic characteristics of traditional timber houses existing in Tochigi-prefecture are investigated from the microtremor measurements. The main results are as follows; The natural frequencies of traditional timber houses distribute from 2.5 to 5.0 Hz, and these values are approximately equal to those of contemporary timber houses, construction stage of which is frame work with bracing members. The damping constants of traditional timber houses distribute from 2.6 to 9.2 %, and these values are larger than those of contemporary timber houses by about 20 %. The damping constant is in inverse proportion to the natural frequency in case of traditional timber houses. It becomes clear that the number of wall and the weight of house are main factors to determine the dynamic characteristics of traditional and contemporary timber houses.

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This paper deals with the allocation problem of multi-story shear walls in 3D RC frames. This problem is formulated as a minimum weight design problem under constraints of ultimate strength, relative story displacement and dynamic eccentric ratio, and designed by the optimality technique based upon the branch-and-bound method that is proposed in our previous studies. In this paper, example multi-story frames with large eccentricities are optimally designed with discussion on characteristics of optimal allocations. Furthermore, guidelines for structural design of RC frames with multi-story shear walls are proposed.

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In case of fewer wall structures, the stiffness decrease of shear wall structure sometimes influences the deformation ability. The eccentric R/C structure is modeled as follow: a) Shear wall is as FEM model, the column and the girder are as line members. B) It is modeled combined 2-dimension frame models. We reached the results as follow: 1) It thinks that the method like this paper of increasing frame strength is rational. 2) Converted the amount of 「the increment of the frame strength」 to 「the increment of the story strength」. It is less than Fe. 3) In the future, further examination is necessary.

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This study aims at examining the relation between the performance of steel members and the material properties. Specimens composed of H-shaped beams and box columns were subjected to seismic motions by means of shaking table test. The range of temperature was set from -50℃ to +15℃ in order to include -15℃, which is the transition temperture obtained from Charpy impact test. All specimens showed high deformation capacities above -20℃ in temperature. When temperature was below -30℃, brittle fracture occurred and the specimen showed the progress of deterioration in strength and deformation capacity according to the temperture.

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This study shows that the 590N/mm^2 high strength steel beam with large depth-thickness ration has enough plastic deformation capacity. 590N/mm^2 high strength steel used in this study has little yield plateau and high modulus at strain hardening region. To begin with, plate local buckling behavior of this steel beam is investigated and compared with that of normal high strength steel beams. Next, large deformation behavior and collapse mode are examined, and plastic deformation capacity is evaluated by using plate thickness ratio. Finally, a limit of shear span ratio that beam is collapsed by web shear buckling is shown.

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Theoretical studies are presented on the prediction of bending strength of a slender composite column. The main objective of this study is to refine the AIJ design formula for slender composite columns which is based on the modified superposed strength method. Investigations are focused on 1) proper N-M interaction relationships for steel and concrete components, 2) upper and lower limit of combinations between steel and concrete strength, 3) actual superposing method. Axial forces shared by steel and concrete are examined in the study. Proposed formula are able to apply for composite columns with wide flange of weak axis bending and cruciform steel.

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This paper presents a evaluation for the deformation capacity of a parallel chord truss of which the chord members are concrete filled circular tubes (CFT truss). The CFT truss could have a stable plastic collapse mechanism without any strength reductions under not only monotonous loading but also alternatively repeated loading, so that the encased concrete in tubular chords would well avoids the chord buckling. In this paper, the conditions for some stable mechanisms are described and the deformation capacities of CFT trusses are evaluated for each mechanism. The covering mechanisms are (1) none of the chords of a CFT truss buckles under monotonous loading; (2) none of the chords buckles under repeated loading; and (3) one of the chords buckles under repeated loading. A sample evaluation demonstrates that CFT trusses could have the superior deformation capacities which could be compared with full web members in steel.

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Characteristics of damage ratio data were discussed using GIS data of buildings damaged by the 1995 Hyogo-ken Nanbu Earthquake. A regression analysis of the damage ratio for two kinds of area unit showed that damage ratios reported by Kobe University were about 60% of those reported by Building Research Institute. An analysis of damage ratios according to different cell areas revealed that the adequate cell size for data collection ranges from 10,000 to 200,000 m^2 from the viewpoints of the number of target buildings in the unit and the resolution level for the damage distribution.

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