The strength and hardness of concrete slab surface is considered significantly affected by bleeding of concrete. It has been reported that dewatering by vacuum processing is quite effective to make concrete high density and high strength. In the earlier report, the authors have already pointed out that there is a strong relationship between the strength distribution and density distribution in the vacuum processed concrete, both gradually decreasing from the top surface to about 15cm depth of concrete. Main purpose of the present study is to discuss the mechanism of the occurrence of such distribution of strength and density, based on consolidation theory. The present paper reports the results of the investigation on the distribution of ingredients in mortar and concrete. Further, a prediction method for the strength improvement of concrete by vacuum processing is also discussed.

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This paper describes the results of a study on wind resistance performance of clay tile roof. In order to get the wind resistance performance of clay tile roof, questionnaire survey on the construction methods were carried out to the clay tile roof construction companies. Pulling-up tests on clay roof tiles were carried out using roof specimens having 4x 4 or 5 x 5 clay roof tiles. Pulling-out test on the fasteners were also carried out. Probabilistic model on wind resistance performance of clay tile roof is constructed based on the data. Damage rate functions were derived based on the model for evaluation of wind resistance performance of clay tile roofs. Regionalized evaluation of wind resistance performance of clay tile roof is shown using the function. Damage ratio can be expected using the function to a given wind velocity.

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The SPatial Auto-Correlation (SPAC) method applied for array records of microtremors provides a S-wave velocity structure by surface wave inversion with sufficient accuracy. The efficiency of the SPAC method has mostly been verified for relatively deep underground structures as a tool of geophysical prospecting. However, efforts to increase its accuracy and develop the tools for measurements and analysis are still necessary for extending and applying the method in practical engineering use, especially for determining shallow velocity structures. We carried out array measurements of microtremors at 7 sites around Kanto area in Japan, where strong-motion stations have already been installed and the underground structures have been determined by other methods, such as PS logging and/or reflection survey. Through the comparison of S-wave velocity structures by various methods, we can conclude that the SPAC method has sufficient precision in practical engineering use.

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For the purpose of investigating the frequency characteristics of the shape of concrete crack surfaces, 25 concrete crack surfaces which were formed under 4 kinds of stress modes in normal strength concrete have been analyzed using 2-dimensional Fourier transform. An analytical method proposed in the previous paper has been applied to evaluate the behavior of amplitude constituent and phase constituent obtained by describing concrete crack surfaces in the frequency domain. The results show the resemblances among the frequency characteristics obtained from all of the crack surfaces that are not affected by the difference of stress modes. And the fact seems to show the possibility of generating standard shape model for concrete crack surfaces.

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Since it is well known that the internal damping of many materials is comparatively frequency independent, an analysis model that can express such characteristics (called a hysteretic damping model) in the time domain is needed. Although a great number of investigations into this subject have been presented, there are very few practical methods. In the frequency domain, a complex damping model is often used for this purpose. But it is well known that this model cannot be used in the time domain because it does not satisfy the causality condition. In this paper, a simple and practical model is presented using the extension of the complex stiffness transform method that the author has proposed. The efficiency of the model is confirmed by applying it to example time history response analyses.

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The previous thesis (Part 1) presented a two-dimensional calculation method for a cylindrical earth retaining structure subjected to wall temperature variations, in addition to lateral pressures. In this study, the authors work out numerical analysis of mechanical behavior of a cylindrical RC earth retaining structure (144m in diameter and 30m in excavation depth). Especially, they take into account (a) the rigidity of the composite wall (earth retaining wall with RC basement wall), and (b) non-linear distribution of wall temperature variations in the composite wall. They compared the results with experimental data, and proved that the cross-sectional stress distribution of reinforcing bars in the composite wall is discontinuous across the interface of the earth retaining wall to the basement wall.

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Seismic responses of lattice domes with substructures are known to be very complicated, because of the dome having large numbers of parallel vibration modes, whose amplitude changes drastically along the stiffness of substructures. Also they are required plastic desigh for ultimate state desigh in heavy seismic areas. In this paper, simple response evaluation method of domes supported by elasto-plastic substructure are proposed using response amplification factors and linearization techniques. Their validities are disucussed against response spectrum analyses with CQC method and time history analyses.

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Seismic response of cylindrical lattice shell roofs with supporting substructures are very complicated, because these roofs have large numbers of parallel vibration modes, and their amplitude change drastically along the relationship between mechanical properties of roofs and substructures. In this paper, several simple response evaluation methods for cylindrical lattice shell roofs with substructures using response amplification factors are proposed, and their validities are discussed against response spectrum analyses with CQC method.

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The purpose of this study is to investigate the vertical dynamic charasteristics of two sorts of hybrid wooden floors. The wooden floor is a 6.5m-long-span and 1.0m-wide and consisted of two 120mm wide and 300mm deep laminated wood timbers with 21mm-thick plywood sub-floor. The hybrid concrete-wooden floor has 60mm-thick concrete slab connected by lagscrews onto the wooden floor and the hybrid ALC(Autocraved Lightweight Concrete)-wooden floor has ALC pannels fastened by wood screws onto the wooden floor. The test results indicate, i) The measured first natural frequencies of hybrid wooden floors coincide with those calculated according to the vibration theory for bending continuous model with the bending stiffness and the weight (the sum of dead-load and furniture-load except the human-load) of the hybrid wooden floor, ii) As the rigidity of the joint of concrete and the wooden floor is small, the frictional force between concrete and the wooden floor is not negligible in the bending stiffness, but hardly gives influence on the damping factor, iii) The damping factor at first natural frequency increases in proportion to the rate of human-load over the weight of the hybrid wooden floor.

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Purpose of the present study is to discuss the compressive failure state and the effectiveness of internal friction angle used in the Drucker-Prager model, based on the uniaxial compression 3-D FEM analysis of plain concrete with the strength variation due to bleeding. As a result of analyses which introduced the different values of internal friction angle (30 and 53 degree), it has been pointed out that 1) the failure zone along the longitudinal direction of specimen shows tendency of proportional reduction with the increase in the size of a specimen, and 2) the distribution of equivalent strain inside a specimen obtained from the analysis with internal friction angle of 53 degree can represent the ordinary failure pattern.

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This paper proposes a new technique for structural control of RC buildings with soft story by using ductile short columns as response control devices placed beside the existing columns at the soft story. The objective of the response control is upgrading safety as well as reparability for damage mitigation without partitioning off the spaces at the soft story. This device is made by High Performance Fiber Reinforced Cementitious Composite (HPFRCC), which exhibits multiple cracking and strain-hardening characteristics in the uni-axial tensile stress. It has been found that the HPFRCC device shows a very good ductile structural manner in conjunction with a high resistance capacity against the axial force. The main role of these devices are to increase story shear capacity to reduce response drift of the soft story, and to support axial force due to overturning moment in order to reduce axial force acting on the soft story columns. A substructure pseudo-dynamic test were conducted in order to investigate the advantages by using HPFRCC devices, and to confirm the seismic response analyses. As the result of the experiment, the seismic response of the RC buildings with soft story was successfully controlled by using HPFRCC device, and the reliability of the analytical tool has also been clarified.

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The paper presents a method of estimating earthquake responses of asymmetric reinforced concrete structures based on nonlinear deformation modes. Shaking table tests of one-third scale six-story eccentric reinforced concrete wall-frame specimens were conducted and analyzed with a nonlinear three-dimensional frame model. A fair correlation was observed between the test and the frame analysis. Several wall-frames were designed by varying the plan, location and stiffness of the walls from the specimen to simulate general cases of torsional responses, where the 2nd mode is dominant as well. The intensities of the earthquake motions for the simulation were also varied to simulate also wide range of structural responses from elastic to inelastic deformations. The dominant modes were derived from the nonlinear responses, in which general characteristics were discussed in terms of effective mass ratio. The value approaches a constant when the inelastic response is large. The constant could be derived from nonlinear pushover analysis considering the first mode and the second mode in the assumed load vectors. A new method of estimating nonlinear responses based on the deformation modes in the dynamic responses are proposed based on the general characteristics. The estimates are compared with the results of nonlinear dynamic frame analysis, where a better correlation was observed than those by past simple methods generally from elastic to inelastic responses.

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This paper presents seismic static test results of hinge isolated reinforced concrete beams with openings at beam-ends. A major variable of test specimens was the arrangement of diagonal reinforcements around openings. The specimens with sufficient anchor length of the diagonal reinforcement showed the typical performance of hinge isolation systems: a broad crack occurred at the beam-ends while damages in the beams were hardly observed, and the specimens were deformed mainly by the rotation at the beam-ends until the drift angle reached up to 1/25 without strength deterioration. The hysteresis characteristics of the specimens with openings were similar to those of the specimens without opening.

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A nonlinear static procedure for single-story unsymmetric buildings subjected to bi-directional excitation is presented and its applicability is discussed. In this procedure, their responses are predicted through a pushover analysis of MDOF model considering the effect of bi-directional excitations and a estimation of the nonlinear response of equivalent SDOF model. The predicted results are compared with the nonlinear dynamic analysis results, and it is shown that the equivalent modal mass ratios of the first and second modes are the indices to discuss the applicability of the presented procedure.

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In order to study structural beheavious of H-section weak axis column to H-section beam connection with high-strength bolts, cyclic loading tests of subassemblage specimens with this connection type are performed. The obtained load-drift angle relationship of each specimen is stable spindle type with satisfactory deformation capacity. The connection strengths of the subassamblage are analyzed by the yield line theory, giving good correspondence with the test results. The effect of the moment-local rotational angle of the connection on the stiffness and deformation capacity of the subassemblages is then discussed.

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Ultrasonic angle beam testing has been conducted so far to maintain the reliability and earth quake-proof in beam-to-column joints. Ceramic tabs have been increasingly used in welding constructions in recent years, therefore they result in closed distribution of defects at end zones. As that result, the conventional ultrasonic angle beam testing has been anxious about the detection of weld defects and the accuracy of measuring defect size in beam-to-column joints. This paper shows stable and adequate evaluation on weld defects in end zones, adopting not only maximum echo amplitude technique but also tip echo technique in reconsidering of probe angles and sizes.

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This paper discusses the seismic response of damage tolerant structure with plan irregularity based on energy response concept. In this paper, the reduction factor of seismic performance due to plan irregularity is defined as the ratio of energy absorption capacity of structure with plan irregularity and that of structure with regular plan. Based on the energy response concept, a simplified equation of the reduction factor is proposed and its applicability is discussed.

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Incorporating additional braces is representative method for seismic retrofit for steel structure. On this occasion, noise and vibration often break out by welding and floor concrete removal during the site work, so seismic retrofits are hard to enforce. The former report proposed a joint method using epoxy resin and chemical anchors. This joint method had less noise and vibration, on the other hand, caused tension stress on the surface of concrete. This paper proposes the improved joint method by using a shear-key plate. This method doesn't directly adhere the joint element to a concrete, adheres a shear-key plate to concrete. This paper reports about the loading tests of the joint portion and the cyclic loading tests of frames to evaluate the dynamic characteristics of this joint.

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Concrete filled tubular (CFT) frames have been widely applied in high-rise buildings since the early 1990s. However, there is a need to seek more cost-effective connection details, and this is especially true for square tubes. To meet this need, a relatively simple and cost-saving solution, in which a connection is stiffened with two interior T-shaped diaphragms, was experimentally investigated. This connection detail has been long used for steel frames; however, its application to the CFT frames has been limited because of the lack of information on the behavior and design guidelines. Based on the test results and observations obtained through this research, strength models and design formulas were derived using a limit analysis technique. Comparison with the test results showed that the proposed formulas provided accurate strength estimates.

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The purpose of this study is to investigate the effects of axial load on inelastic behavior of steel reinforced concrete columns. A total of 9 steel reinforced concrete columns with cross-shaped structural steel were tested under constant or varied axial load and repeated lateral load. In designing the test work, the axial load level and the shear-span to depth ratio were chosen as main parameters. Based on the test results, inelastic behavior, maximum strength, deformation capacity, as well as the effects of axial load and shear-span to depth ratio on are discussed. Elastic-plastic analyses on all specimens were carried out. The analytical results accord well with the test results.

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The purpose of this study is to obtain the S-wave velocity structure of Suwa basin. Array observations of microtremors were done at five sites in Suwa basin. The SPAC method was applied to the array observation results and the S-wave velocity structure from the ground surface to the seismic bedrock was obtained by surface wave inversion. Microtremor H/V spectra were also obtained at forty two sites in the basin. The S-wave velocities of shallower parts of the ground were obtained by the H/V spectra analyses. Results of the observations are: (1) the depth of the seismic bedrock is 4.3km at the central part of the basin and from 2.7 to 3.3km at the edge, (2) the depth of the layer which S-wave velocity is 400m/s is about 130m at the central part of the basin and from 20 to 40m at the edge. As mentioned above, the underground structure of the basin is bowl-shape.

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