This study discusses the relationship between strength and ductility of vertical placing joints of concrete specimens, each of which has one of 5 differently treated surfaces. The main feature of this study is that the authors employed both tension softening diagram (TSD) and pull-out dowel model for discussion. The conclusions are as follows.
1. Relationship between tensile strengths of specimens with joint and no-joint is a linear one reflecting the fractured area on the surface of the joint. These strengths would be considered the sum of those by matrix and dowels in dowel model.
2. The strong interface would be modeled to have longer dowels that cause the longer critical crack width in TSD, which leads to larger fracture energy, and vice versa.
3. The dowel model proposed in this study can describe some important aspects in achieved TSDs of specimens with joint.

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Experiment by authors showed that lateral strain at the center in a real size column using ultra high-strength concrete was larger than longitudinal one. This phenomenon indicates that stress, which may cause longitudinal crack, is produced in the RC column when the isotropic autogenous shrinkage is assumed. Based on this experimental facts, 3-dimensional finite element method which takes account of temperature dependent autogenous shrinkage is conducted for evaluating stress in the RC column. As a result, it is numerically confirmed that temperature history and autogenous shrinkage produces self-induced stress in cross-section which is vertical to longitudinal direction of RC column.

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In this study, analytical and experimental investigations were conducted to clarify the effect of clad reinforcement by polyethylene fiber reinforced mortar (PEFRM) on flexural characteristics of reinforced concrete (RC) beams strengthened with polyethylene fiber sheets. High-performance polyethylene fibers (PEF) were used for making the PEFRM with high tensile strength. The PEFRM-cladding was performed on the tensile side of the RC beam. The RC beams strengthened with the PEFRM-cladding and the sheets were tested under pure bending. As a result, it was shown that the PEFRM-cladding has a remarkable effect on an improvement of flexural reinforcement by the sheets of the RC beam.

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This paper describes analytical results by a boundary element method on interfacial stress singular conditions near the tip of shrinkage crack terminating at the interface between the concrete bodies and cemeticious adhesive mortar. A general stress function near the stress singular points is theoretically presented by a linear combination of the singular solutions of type r^-λ, the no singularity solutions and the particular solutions which are independent of distance r from the crack tip by a fracture mechanical method. A new method is presented to obtain the values of several kinds of singularity parameters. Furthermore, the usefulness of these methods and the characteristics of the three parameters under different influences of several kinds of finishing conditions are discussed.

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In estimating the unbalanced snow loads on roofs of buildings in cold and heavy snow regions, it is important to consider the aerodynamic influence of buildings on shaping snow accumulations. At present, the information from snowstorm wind tunnel tests are effective to predict the typical snow accumulation patterns on various roof shapes. On the other hand, it will be useful if it is possible to estimate the snow accumulation patterns from simple characteristics of the wind flow around a building. This study focuses the relationship between the snow accumulation from snowstorm wind tunnel tests using artificial snow particles and the distribution of the mean wind pressure coefficients on roofs from the general wind tunnel tests. As a result of investigating five types of roofs such as a flat roof, a flat roof with parapet, a two-level flat roof, a hemisphere dome and a gable roof for a single snowstorm, it is found that the formation of the snow accumulation on roofs strongly depends on the gradient of the mean wind pressure coefficients on roofs.

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In Japan, buildings are constantly exposed to the earthquake risk. Various researches dealing with the earthquake risk have been undertaken very actively in Japan. Most of these researches, however, focuss on the risk due to main shock while researches treating aftershock risks has been seldom paid attention to so far. Although it is obvious that the major building damage comes from the main shock, it has been reported that some serious building damage occurred due to a series of aftershocks of the Chuetsu earthquake on Oct.23, 2004 in Niigata area. That is why it is necessary to demonstrate how much the seismic risk increase when taking into consideration of aftershocks.
It is assumed that the relationship between the magnitude of aftershocks and the total number of aftershocks can be represented by the Gutenberg-Righter law, and the relationship between the elapsed time after the main shock and the occurrence rate of aftershock follows the modified Omori's law. Using the ground motion attenuation relation together with the above two laws, the ground motion caused by aftershocks can be calculated and then an aftershock hazard can be estimated.
In this paper, three damage states of buildings, corresponding to the three modes of an event-tree in the Markov chain, are taken: collapse, half collapse and no damage. Then the seismic risk of aftershocks along with the main-shocks can be evaluated theoretically by use of an event-tree and the Markov chain. The Markov chain is very appropriate because the occurrence rate of aftershocks varies depending upon the elapsed time, and the state of buildings might change due to consecutive occurrence of aftershocks. In some numerical examples, show the important result.

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To examine the performance of furniture in the top stories of high-rise buildings particularly under long-period ground motions, a full-scale shaking table test was conducted in E-defense. A mass-and-rubber system was designed to overcome the limitation of the shaking table. A five-story specimen with large stiffness was set on the rubber-and-mass system. It enables that different stories' responses are same and a lot of furniture experiments are carried out simultaneously. The waves generated from the inverse dynamic compensation were taken as inputs. The test results show that the large responses at the top stories can be reproduced reasonably. Through the shaking table test, physical data of furniture in high-rise buildings under long-period ground motions were obtained.

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In this paper, the scaling equation between the pseudo velocity response spectrum and the energy spectrum is proposed. Utilizing random vibration theory, the maximum response of SDOF is given as the function of power spectrum density of main part of earthquake motion. Whereas, energy spectrum is equal to Fourier amplitude spectrum smoothed by spectral window, which is clearly pointed out by Kuwamura, et al. Finally, the equation between response spectrum and energy spectrum is derived, by making connection between Fourier amplitude spectrum and power spectrum density considering the nonstationarity of earthquake motion. The proposed equation is verified not only using the artificial earthquake motions but also using the observed strong ground motions of both interplate earthquakes and inland crustal earthquakes. The equation between the peak ground acceleration/velocity and response spectrum is also proposed, which is the application of the method shown in this paper.

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This study was conducted to investigate by experiment changes in the horizontal earth pressure that acts on the retaining wall surface and then examine the effect of soil improvement on uniformly distributed load on the ground surface. The results of this study are summarized below.
(1) I n any of the cases of soil improvement, the earth pressure that acts on the surface of the retaining wall falls significantly several days after ground preparation.
(2) When soil improvement is done, no horizontal earth pressure with uniformly distributed load on the ground surface acts on the retaining wall surface at the improved part of the ground.
(3) The wider is the range of soil improvement (θ), the smaller is the amount of the horizontal displacement of the retaining wall with uniformly distributed load on the ground surface.

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Previous studies have suggested that rocking vibration accompanied with foundation uplift motion might reduce the seismic damage of buildings subjected to severe earthquake motions. In this paper, the seismic response of ten-story steel frames with columns allowed to uplift is evaluated and compared with that of fixed-base frames by numerical analyses. It is shown that the base shears in the frames with column uplift are significantly reduced as compared to the fixed-base frames, and that the vertical component of earthquake motions does not much affect the horizontal responses of uplift frames but increases slightly the uplift response displacement of uplift frames.

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Seismic response of arch structures with supporting substructures is known to be amplified in vertical directions even under horizontal input, and their amplitude changes along the relationship between mechanical properties of roofs and substructures. Although a large number of studies on seismic response behavior by numerical analyses have been made, seismic response behavior by vibration test has not been sufficiently investigated. In this paper, seismic vibration tests are carried out using small scale arch roof models with supporting substructure in order to confirm influence by the relationship between mechanical properties of roofs and substructures. The validity of response evaluation method proposed in previous papers is examined.

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In order to realize reliable tension structures, it is very important to make an appropriate plan for introducing tensile force in its construction process. For this purpose, "Unit-based" structure is useful and convenient. Unit-based tension structure is a system that is composed of structural units stabilized by introducing initial stress. In this paper, a very simple method for introducing tensile force considering the interaction between units is proposed. After the influence of the interaction is studied with a very simple model, it is proved that the final stress condition is largely affected by the means of introducing tensile forces in each units. Finally a simple method is proposed and the validity is examined by some simulations imitating actual construction process with plane and three-dimensional models.

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This paper describes a case study of cost-effectiveness of seismic retrofit measurement for vulnerable wood houses. To examine the cost-effectiveness of seismic retrofit measurement, the life cycle costs for five houses having different seismic performance and being located on five different areas are compared. These seismic performances are defined from the results of full-scale shaking table tests including collapse tests and static loading test on the site, and time history analyses were conducted to compute damage cost. The field survey also was conducted to evaluate the relationship between damage and rehabilitation. As the result of analyses, there are quite big differences in seismic zone. For example in Shizuoka where is high probability of severe earthquake seismic performance assessment score of 1.5 is the most cost-effectiveness, but then in Tokyo seismic performance assessment score of 0.3 which means no reinforcement of vulnerable wood house is the most cost effectiveness in next 20 year. When calculating the effective cost in next 20 year all area, it is estimated half of the current amount.

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This paper attempts to predict analytically large deformation static behaviors of two story wooden frame walls from the static performances of members and joints which compose wooden frame houses and walls. Wooden frame walls in this study have fragile joints which need to consider repeated contact problems, therefore extended distinct element method (EDEM) are applied which can consider these problems.
110 joint specimens are tested. They are pressed in axial side, bent inside and outside. From the results of these tests and the past researches, the two story wooden frame walls are modeled. Especially, because of the brace failure modes of pressing side, four kinds of models are proposed for each wooden frame wall. The comparison of the results between EDEM analyses and tests indicates, 1) in the range of assumed brace failure mode, proposed models can predict test results, 2) by considering brace models in detail, proposed models can reproduce test results precisely.

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Shear failure of columns may lead to collapse for existence buildings. After a severe earthquake, some buildings collapsed by loss of axial capacity of the columns, however, some buildings have stayed even many columns were fractured by shear. For the examination of building collapse, it is required to investigate the axial load capacity of the columns after shear failure and to analyze the building performance using the pertinent analytical model for the columns. This paper investigates the analytical model for the collapse analysis of a building based on Yoshimura's concept of the failure surface contraction. The reduction rate was obtained as a function of the maximum deformation, shear margin ratio, and so on, using the regression analysis of experimental results. The tested results are explained by this formula with good agreement.

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The design criteria for SRC T-shaped and L-shaped beam-column joints utilizing mechanical anchorages are proposed. The design criteria are based on the formulation of the joint shear force demand at the ultimate strength of SRC beam or column bending as well as the joint shear force capacity. The specific features of the formulations include: (1) the influence of the variation of axial force in the beam on the joint force demand is considered for SRC L-shaped joint, similar to RC L-shaped joint proposed previously, (2) the influences of anchorage length of reinforcement and steel member on the joint concrete strength are considered in the formulation of the joint shear force capacity, similar to SRC exterior joint proposed previously. Proposed design criteria are verified through the experimental data on the 6 specimens of T-shaped and L-shaped beam-column joints.

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The necessity of finding a design method was awakened for preventing brittle fracture which was observed at beam-to-column connections in steel moment frames in Kobe at the event of the 1995 Hyogoken-Nanbu Earthquake. The plastic deformation capacity until brittle fracture is an important variable for the design, while is of much uncertainty in the past experimental data due to weld. Then artificial notched specimens without weld are required for investigating the effects of earthquake motion on the fracture resistance. However, it is useless if the stress-strain states of actual beam-to-column connections are not represented by those of artificial specimens. In this paper, notch models were constructed based on the investigation of geometrical and metallurgical discontinuities brought by welding of actual beam-to-column connections. The stress-strain states of the notch models were studied by FEM analysis. Then notched specimens made of base material, which are called equivalent models, are designed for representing the stress-strain states of the actual connections.

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An anchor-bolt-yield-type column base shows slip-type restoring force characteristics. The column base subjected to constant axial and cyclic horizontal forces shows more complicated characteristics. An experimental study on the column-bases under constant axial-force and cyclic bending was carried out. The following conclusions were obtained from the loading tests;
1) There types of resistant mechanisms of the column-base under constant axial-force were classified to evaluate the strength and the elastic rotational stiffness.
2) In case of tensile axial-force N=57(kN), the restoring force characteristics of the column-base were obtained combined all types of the resistant mechanisms.
3) In case of tensile axial-force N=117(kN), the restoring force characteristics became perfectly elasto-plastic curves without slip behavior.

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Theoretical studies are presented on the prediction of strength of a wide flange beam-column in a multistory frame subjected to vertical and horizontal forces at the earthquake. P-Δ effects are taken into account of the column deflection itself and that of adjacent beams. Explicit expressions of the moment magnification factor are introduced as the function of dimensions of column and adjacent beams. If the adjacent beams are stronger than the column, the strength of the system is determined by the column strength, and vice versa. Proposed method shows a good agreement with precise numerical solutions.

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The plastic constraint condition affects the occurrence of brittle fracture. This effect is very important because many of the weld defects in beam to column connections are small cracks, although the material toughness is measured using a specimen with a deep notch. This paper shows the ability of the simplified model to predict brittle fracture under low plastic constraint conditions. Fracture toughness tests of SENB specimens with a shallow notch, and tension specimens (DENT and CNT) were performed and these specimens showed higher fracture toughness compared with SENB specimens with a deep notch due to a loss of plastic constraint at the crack tips. The Weibull stress approach and toughness scaling model were used to consider the effects of the loss of plastic constraint on the fracture toughness of the specimens. The corrected fracture toughness values evaluated by the toughness scaling model were found to be close to the toughness values observed in the tests as well as the values predicted by the Weibull stress approach.

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When non-structural members are used as eccentric braces in real structures, flexural and torsional deformation of compression members may occur due to the eccentric joints to the braces. This paper clarifies the buckling behavior with web deformation for H-shaped compression members with laterally and rotationally eccentric braces. The elasto-plastic buckling stress is evaluated with the buckling curve for design codes using the modified equivalent slenderness ratio. Then the elastic buckling load with energy method is applied to the slenderness ratio. In addition, the relationship between the required rigidity and strength of braces is evaluated.

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