Properties of blast furnace slag fine aggregate and compressive strength of concrete using blast furnace slag fine aggregate were studied on following 3 aspects.
1. Properties including of absorption, density, grading and crushed value of blast furnace slag fine aggregate coming from 3 different steel factories and 1 type of natural river sand used as contrast are studied.
2. Properties including of slump, slump flow, air content and density about fresh concrete using blast furnace slag fine aggregate and river sand were tested.
3. Compressive strength of concrete using blast furnace slag fine aggregate was studied. Furthermore, influence of blast furnace slag fine aggregate on compressive strength of concrete was discussed.

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Even in case of conventional concrete, cracks width of about 0.1 mm or smaller is relatively safe due to self-healing autogenously achieved by immersing moisture. In this self-healing phenomenon, fiber reinforced cementitious composites (FRCC) that enable to keep the crack width smaller can be greatly effective. In order to investigate the self-healing capability of FRCC, some experiments were carried out that focused on the recovery of mechanical properties and chemical precipitation on the crack surface. Kinds and length of the contained fibers were adopted as the experimental parameters. These specimens, in which cracks were introduced by tension test, were cured in water after introducing cracks. The self-healing capability of the specimens was investigated by means of microscope observation, water permeability test, and re-tension test. It was found that a lot of very fine fibers were bridging over the crack and crystallization products became easy to be precipitated around such bridging fibers. Additionally, the increasing rate of the thickness of the crystallization products during the initial stage is higher than that of the latter stage. As a result, water permeability coefficient was recovered significantly. However, mechanical properties were restored slightly. Furthermore, it was shown that different types of fibers led a different performance of the self-healing effect.

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This paper describes the study on the appropriate test method of the dry density for the shielding concrete. A series of experiments was conducted based on the Latin square method considering cement type and test condition variability. The following conclusions can be drawn.
1. The drying convergence time of a concrete specimen depends on the pre-curing period, the shape of the specimen and the drying temperature. The longer pre-curing period, larger specimen size and lower drying temperature make the drying convergence time longer.
2. Although there are two judgment criteria for oven-dry condition of the concrete specimen and these two criteria influence the drying convergence time, these two criteria do not influence the dry density of the concrete specimen.

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This study made it clear that the following parameter ”eqr” can determine the tensile shear strength of resistance spot welded joint. This parameter “eqr” represents the residual heat quantity of the contact part of the welded plates after welding time. It includes spot welding current, welding time, electrode force, electrode tip diameter and welded plate thickness.
It was made it clear by experiments that the parameter ”eqr” can be applied to estimate the tensile shear strength of uncoated steel and hot-dip coated steel that were the carbon steels strength class less than 490N/mm².

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This paper reports the evaluation method of the waterproofing system for underground structure applied on earth retaining walls prior to concrete casting. The most important part for evaluating waterproofing properties of this system is a penetrated part through waterproofing, or a damaged part of waterproofing. For the penetrated part, the specimen of this system should be made of concrete casting vertically. For the damaged part, the specimen should be made of concrete using tall frame and casting vertically, or using small frame and rotating to accelerate bleeding. Then waterproofing property of this system is evaluated by pressurizing permeability test.

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In order to understand the quantitative delamination behavior of the external wall which consists of tiles, mortar and concrete, Non-linear and two-dimensional FEM model was modified and verified with experimental data. The conclusions from FEM analysis and experiments are below.
1.The Delamination model was modified with the bond model.
2. The quantitative delamination behavior was reproduced by the delamination model.
3. In order to reduce the risk of the delamination, it is necessary to measure the data concerning strength, rigidity and displacement of the delamination layer.

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Performance-based seismic design of structures has been widely recognized as useful design concept, in which required performance such as safety, serviceability and others are explicitly described, and the required level of the performance are quantitatively specified. The required level has often been expressed in terms of return periods of earthquake ground motion intensities such as PGA or spectral acceleration, all of which do not fully represent ground motion time histories. Recent advancements on theoretical as well as semi-empirical fault models in engineering seismology should be incorporated to meet the required performance levels of structures. Therefore, this paper proposes a new reliability- based methodology for determination of source parameters of the fault model which correspond to the return period specified by design requirement.

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Based on awareness that observed strong ground motions have been dramatically accumulated, we proposed “Seismic Wave Inventory” (Tanaka & Takada, 2009), which is the wave selection method from observed database. In this study, the concept of Seismic Wave Inventory is expanded for probabilistic seismic hazard analysis as well as for a design ground motion selection method corresponding to a target return period. First, we conduct seismic hazard analysis. The feature of our method is that occurrence probability is given to each ground motion based on occurrence probability of each earthquake source. This gives uncertainty of ground motion intensity level, where the theoretical distribution (e.g. Log-normal distribution) is employed in the conventional method. A seismic hazard curve represented by an arbitrary intensity measure can be calculated. Then, set of design ground motions can be obtained corresponding to a target return period, which definitely satisfies the contribution factor in each magnitude distance bin.

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As a key point to examine the applicability of force response reduction due to uplift to non-slender buildings, the effect of rotational inertia on the dynamic uplifting behavior is investigated by means of classical modal analysis. The system considered is a two dimensional uniform shear-beam. Following eigenvalue analysis in the uplift phase, the free vibrations under gravity are investigated. The results show that the maximum force responses, e.g. base shears, etc., are significantly reduced, even if the rotational inertia is relatively large. But the force responses in non-slender buildings are a little bit larger than those in slender ones.

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In this paper, the influence of soil-structure interaction(SSI) effects on maximum displacement response of low-medium rise reinforced concrete building with relatively high strength are studied. A practical procedure with a simplified model including nonlinear SSI effects to predict maximum displacement response is proposed. Shear force-displacement relation and damping factor including SSI effects are obtained by using maximum displacements response of simplified model and surface ground layer due to strong ground motions. The maximum response estimation due to strong earthquake motions is demonstrated using example models of reinforced concrete 5-story building and surface ground deposit. The validity of proposed procedure is examined in comparison with the results of nonlinear response analysis using 2-dimentional FEM model.

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In this paper, seismic response characteristics of high ductile structures with embedded foundation surrounding soil ground are evaluated. First, transfer functions of embedded foundation considering the time delay components are proposed based on Dynamic Ground Compliance and Novak method. Next, seismic responses of equivalent single degree of freedom systems using proposed transfer function are calculated by the difference of the first natural period and the ductile level of upper structure. Response measurement focuses on the story shear force, the displacement, the energy absorption by hysteretic for upper structures and radiation damping for soil ground. As a result, it is clarified that the tendency to the embedded depth in the characteristics of each response. The effects of the radiation damping are confirmed in the high ductile structures as well as usual structures, especially, the phenomena are effective when the small displacement amplitude on time history response analysis.

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Shaking table tests were conducted on human subjects to obtain dynamic response data and produce dynamic human models. These models are aimed for applications of structural control and organoleptic evaluation of vibration. Reaction forces were measured against sinusoidal sweep excitations. The results showed that, under standing conditions resonant frequencies are around 0.5Hz for lateral reactions, and less than 0.25Hz for front-back reactions, while under sitting conditions they are 2 to 3 Hz for lateral reactions, and 1 to 2 Hz in front-back reactions. SDOF model and 2DOF model were identified as human models based on these tests.

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A series of shaking table tests on a high-rise building are conducted in order to assess effects of retrofit using steel dampers. The specimen consists of a four-story steel frame and an upper substitute layers made of concrete slabs and rubber bearings. Steel brace dampers are attached to the steel frame, and modeled steel dampers are utilized for the substitute layers. Long-period ground motions and a design ground motion are used for the tests. Total input energies of the specimen reasonably correspond to the estimations of energy spectra. The deformations of specimen are reduced especially in the portion having dampers. In the steel frame, the energy is mostly dissipated in the steel brace dampers. The capacities of the steel brace dampers are estimated about ten times larger than the seismic demand in a strong long-period ground motion.

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The purpose of this study is to evaluate the optimum damping coefficients of Maxwell type viscous dampers which maximize the damping factor of a structural system. The damping factor is stochastically estimated based on the energy response of the structural system under a white noise excitation. It is found that the optimum distribution of the non-dimensional damping coefficients is nearly proportional to that of stiffness coefficients of Maxwell type damper elements. The approximate distribution model is also proposed based on this finding. The effectiveness of the optimized damping system is then demonstrated through the response analysis for several observed earthquake excitations.

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Fire-induced collapse behaviors of a high-rise building with an outrigger truss system were verified using the ASI-Gauss technique. The effects of fire patterns and structural parameters on the redundant strengths were surveyed by observing the collapse initiation time: the duration from the beginning of the fire until collapse initiation. From the numerical results, it is confirmed that collapse initiation times are significantly affected by the member joint strengths if the axial force ratio is small on the condition that the fire pattern is nearly symmetrical, and the load paths to and from the outrigger truss system are sufficiently protected.

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Horizontal load-carrying capacity of steel rigid-frames is one of the most important mechanical performances required in the practical design. Design horizontal load is lowered by the structural property coefficient Ds, which is determined by the plastic deformation capacity of the frame. A practical method using branch and bound approach for the optimization of steel frame structures considering the discontinuity of structural property coefficient Ds is proposed in this paper, and is verified by three numerical examples. The difference between the solutions under Ai distribution lateral forces and Q_un distribution lateral forces is also discussed.

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The restoring force characteristics of rotational embedment of wooden joints are very important to evaluate the seismic performances of traditional timber structures. Some characteristics of wooden joints are discussed and Elasto-plastic Pasternak Model is applied to formulate them effectively, taking the strain hardening and the orthotropic properties into account. In the formulation, the stiffness function depending on the strain levels is introduced to express the rotational stiffness simply in both elastic and plastic states. Then the formulation of crosspiece joints is discussed with rotational embedment tests.

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The seismic performance of old R/C medium-rise residential buildings before and after slit installation on short columns is studied and compared by conducting the nonlinear frame analysis considering column strength deterioration. The study has revealed that, 1) when ground motions with the maximum velocity of 75 cm/s are considered, the possibility of collapse for the building with slits is greatly reduced because the deformation capacity of short columns is improved, but 2) when ground motions with maximum velocity of 25 cm/s are considered, the amplitude of inter-story drift for the building with slits increases due to the elongation of initial period and the increase in inter-story drift at maximum strength.

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The authors have conducted a series of experimental studies on the response characteristics of controlled rocking systems. This system comprises components that include a rocking frame, post-tensioning anchorages, and energy dissipation fuses, eliminating the residual deformation after the earthquake. In this paper, the shaking table test of the controlled rocking system using a Buckling Restrained Brace as the energy dissipation fuse is discussed, including analytical simulations. A procedure to estimate maximum response is introduced based on the concept using maximum instantaneous input energy. The characteristics of the input energy and the accuracy of the proposed approach are demonstrated by comparing the prediction with numerical results as well as experimental results.

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Buckling loads of columns subjected to two kinds of varying axial force are calculated. The analytical models are a column which has two different sections subjected to two different axial forces and a column subjected to liner varying axial force. The buckling equations are derived by using the slope-deflection method for stability and the Galerkin method and the effective length factor and the buckling strength in the inelastic range are calculated. The buckling strength calculated by using the effective length factor concept are compared to the accurate buckling strength and the validity of the effective length factor concept in the inelastic buckling is discussed.

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Seismic response of the passive controlled structure using buckling-restrained braces (BRB) can be ensured when the BRB connection have sufficient strength. This paper investigates demand of connection strength considering hysteresis characteristics of high-strength bolt connections. Cyclic loading test are conducted to clarify hysteresis characteristics of connection including slip behavior under excessive bearing displacement, and the analytical model of connection is proposed from test results. By using the proposed analytical model, seismic response of steel frames with BRB dumpers are numerically analyzed and the strength of BRB bolt connections necessary to secure sufficient energy dissipation and dumping effect is suggested as connection factor.

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A new hysteresis model for high-damping rubber bearings is proposed, which has been developed based on an elasto-plastic, integral type deformation history constitutive law. One of the characteristics of the proposed model is the applicability of the same material parameters as the proposed model to finite element method analyses. Firstly, we derive the horizontal biaxial hysteresis model from the elasto-plastic constitutive law. Next, we compare the results of numerical analyses using the proposed hysteresis model with experimental results for tests of high-damping rubber bearings subjected to horizontal biaxial loading, and verify the validity of the proposed model. Lastly, we perform finite element method analyses and numerical analyses using a multi-shear springs model, and the results from each of these cases are compared with results given by the proposed model.

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