The purpose of this study is to indicate a method of deciding the proportioning strength of precast concrete according to element type and strength level, such as a shape of element, a cross sectional dimension of element, type of cement, quantity of cement, curing condition.
It was concluded that proportioning strength of precast concrete using normal portland cement or high-early-strength portland cement could be determined with the strength of test specimens cured under the same condition as an actual precast concrete element, except high-strength precast concrete elements and precast concrete elements with large cross sectional dimensions. Proportioning strength of precast concrete using low-heat portland cement could be determined with the strength of test specimens cured under the same condition as an actual precast concrete element, except a high-strength precast concrete column.

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This basic research is that focused on that not only repair effect immediately after the repair (initial performance) but also necessity of valuate its persistence in the environment of various weather in order to select a reasonable crack repair materials.
In this report, we simulated the temperature of weather in japan at the laboratory level to perform bending tests, environment under -10°C, 5°C, 23°C, 40°C and 60°C, for mortar specimens that were subjected to single repair material and repair cracks, so we extracted four types of materials, three types of epoxy resins repair materials and one type of acrylic resin repair material, that are widely used as a crack repair materials.
The results shows importance that to clarify the effect that the decline of repair materials or change of a single repair materials are quite different for each repair materials and to evaluate the persistence of the effect repair.

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The effects of high temperature curing on hydration reaction and strength development of cement paste containing silica fume at low water binder ratio were examined. The evaluation yielded the following findings:
1. Compressive strength was increased when the curing temperature became high, and the optimal mix rates of silica fume for strength development differed according to the curing conditions.
2. The gel space ratio that was calculated from the phase composition based on absolute density could explain the compressive strength of 300N/mm²-class hardened cement paste. Therefore, it was suggested that compressive strength was governed by the macroscopic strength resulting from the pore volume of the whole space where a hydrate is generated.
3. Under high temperature curing, the hydration product of low Ca/Si molar ratio was generated and the density was low.

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Free standing steel structures, whose column bases are not fixed to a foundation, contribute to decrease damage to the structures under large earthquakes. However, the friction coefficient of normal steel column bases is 0.8 and too high to the strengths of normal steel structures. In this study, a steel column base lubricated by graphite well known as a lubricant and a cast iron column base containing much more graphite than steel are proposed to realize the low friction column base. Shaking table tests are conducted to investigate the friction characteristics. The tests show that the friction coefficient of the cast iron column base is 0.25 and that of the graphite lubricated steel column base is 0.20. Dynamic response analyses representing these friction characteristics show reasonable correlations with the test results.

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The probability distribution of the residual displacement of a bi-linear single-degree-of-freedom system with isotropic hardening rule or kinematic hardening rule is discussed in this paper. From dynamic analysis results, it is shown that the dynamic behavior with isotropic hardening model agrees with the hypothesis, but the kinematic hardening model does not. In order to eliminate the shortcoming, the absorbed energy at every single plastic deformation is assumed constant in addition to the original random walk hypothesis. The probability distribution estimated under the hypothesis showed good agreement with the dynamic response results with kinematic hardening model.

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The objects of this paper are to comprehend the response characteristics of buildings and subsurface ground for pulse-like ground motions, and to clarify the generating mechanism of the distinctive responses. To achive the objects, we analyze the responses of uniform elastic shear beam for simple pulse waves (sinusoidal pulse and Ricker wavelet), with modal analysis and wave propagation theory. Especially, we focus on the time, the position and the amount of the maximum response, and on the contributing ratio of each natural mode for the maximum response. Additionally, we refer to damage concentration characteristics qualitatively.

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Simplified theories are proposed for seismic response evaluation and preliminary design of RC building structures added with elasto-plastic dampers. They are based on the single-degree-of-freedom (SDOF) idealization of multistory building, and produce the control performance curve expressing the peak responses as a function of stiffness of all components, based on spectral characteristics of the earthquake. Against the target peak response, a rule to convert the SDOF design to multistory design, with consideration to distribute damper stiffness over the building height, is also presented. Accuracy of the approach is demonstrated by passive control design and time history simulations on two RC buildings.

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This paper focuses on use of supplemental stiffness and damping to reduce seismic responses of one-story torsionaly coupled structural systems having uni-axial stiffness eccentricities. Adding stiffness to minimize stiffness eccentricity can most directly reduce the torsional response, but increases translational acceleration and corresponding lateral force. In contrast, adding damping in a manner to produce “damping eccentricity” controls both the torsional and translational responses, by increasing the system damping ratio. Combining both approaches can lead to effective and economical solution. The response prediction rule for such a non-proportional damping system using real-valued modes was proposed earlier by the writers, and is modified to be more simple and accurate in this paper. Using the rule, performance curves clarifying relationship between structural parameters and response parameters are proposed. The curve can determine required supplemental stiffness and damping to reduce both torsional and translational responses, and is extremely useful for sizing and horizontally distributing dampers in the system.

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The response spectrum method is useful for illustrating overall characteristics of dynamic behavior as well as for estimating seismic response of structures. We proposed an estimation method for nonlinear response based on the effective period of transient vibration. The formula of the effective period is derived from backbone curve which has been discussed in the area of nonlinear vibration theory. Parametric response analysis of elasto-plastic and origin-oriented single-degree-of-freedom systems subjected to pulse-wise sinusoidal excitation was carried out. The results of response analysis were compared with the values estimated by the proposed method, and accuracy of the estimation method was examined.

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The basic measure against a vibration proof design is to take effective steps to vibration proofs and to keep vibrating generators and precision machines apart as far as possible. As one of the effective measures against the vibration proof, a vibrating generator is installed on the underground stories. But it's impossible to install all the vibrating generators there. The author can't help installing the medium vibrating generators on the flat slabs near the precision instruments. The purpose of this study is limited to solve the effective mass for the slabs with arbitrary thin length ratio. As support conditions the author calculated the 1^st; the simply support along edges, the 2^nd; the fixed support along edges, the 3^rd; two adjacent edges simply supported and the other edges built-in, the 4^th; the semi-fixation.

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A method is presented for shape optimization of latticed shells defined by parametric surfaces. The latticed shells with rectangular and triangular grids are optimized for maximum stiffness (minimum strain energy) and constructability (uniform member lengths). It is first shown that the latticed shells with completely uniform member length can be generated by solving an optimization problem with nodal coordinates as design variables. Next, the latticed shells are modeled using Bézier surfaces in order to reduce the number of design valiables while maintaining the complexity and smoothness of the shell surface. Although the shape of a parametric surface is usually optimized using the coordinates of control points as design variables, we use the parameter values at the nodes of the grids, in addition to the coordinates of control points, as design variables. The optimization results using different design variables are compared in the numerical examples.

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The present paper discusses on ultimate strength of a shallow reinforced concrete dome supported at four corners, the peripheries of which are stiffened by edge beams of a relatively large depth. The loads for investigation are not only dead load but also approximate earthquake loads considering horizontal earthquake forces together with anti-symmetrical vertical component caused by horizontal earthquake motions. The method is based on an elastic-plastic geometrically nonlinear analysis considering both effects of initial geometric imperfections and tensile strength of concrete. Based on the results, several important structural features are revealed. The geometric imperfection distribution similar to those caused by dead load reduces the ultimate strength, and the strength is also much reduced if no tensile strength is assumed for concrete, while the inverse imperfections much increase the strength. The ultimate strength interaction between dead load and earthquake loads shows the importance in design to include the anti-symmetrical load components of earthquake loads. Finally, the importance of stiffeners at free edges is confirmed and shell geometries of bending moment-free are suggested for increasing strength.

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We have conducted static loading tests of plane frames of a two-storied traditional town house in Kyoto, Japan. In our study, we have developed a loading system in order to apply large shear deformation angle of 0.2 rad. Based on our tests, some new findings have been acquired as follows. (a) A sharp decrease in story shear force due to shear failure of the mud wall is not observed. (b) Concentration of deformation or damage in a specific story will be prevented by the existence of pillars. (c) While houses will not slide as one-body system, some columns with small axial force move independently. (d) Some phenomena neglected in the current seismic design in Japan have been well recognized.

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This paper describes vibration characteristics of Nikko-zan Rin-noji temple Hondo (main hall) for the 2011 off the Pacific coast of Tohoku Earthquake and its aftershocks. From rare records observed in the traditional wooden structure, the characteristics are identified by the forgetting factor recursive least squares method. In the first translational mode, the natural frequency decreases and the damping factor increases with increasing deformation. It is expected that the nonlinearity is recoverable, because the results of microtremor measurements almost never change before and after the mainshock. The vibration characteristics in torsional mode show independency on increasing deformation.

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Fracture modes of wood in mechanical joints with a single stiff bolt loaded parallel to the grain were experimentally investigated. For the end margin less than two to four times the bolt diameter, the ultimate state was governed by premature failure either of end transverse tensile or push-out shearing fracture in a brittle manner. For the end margin greater than that, the ultimate state was by splitting fracture, and the maximum strength kept nearly constant due to bearing yield of wood underneath the bolt, in that the embedding deformation up to the fracture increased with the end margin. The circumferential friction acting on the contact arc between bolt and wood gave a moderate effect such that the frictional coefficient enhanced the joint ductility as well as strength. The support condition in the opposite side of the test joint showed little effect on the ultimate behaviors.

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This paper proposes a seismic retrofitting technique for existing RC columns with cast-in-place RC sidewall using polymer-cement mortar (PCM). In the technique, additional shear reinforcement (deformed steel bar: prefabricated reinforcing unit) is adhered to the surface of existing RC columns with RC sidewall by PCM. Shear-loading tests were conducted to clarify the structural performance of the columns with sidewall strengthened by polymer-cement mortar. The results suggested that the capacity and ductility of the strengthened RC column with RC sidewall could be controlled by choosing the strengthened area and the amount of shear reinforcement. Furthermore, the shear force Q &mdash drift angle R curve of RC columns with RC sidewalls retrofitted by RCM was proposed by considering the shear resistance mechanism.

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The conventional seismic design of buildings with the pile foundation often uses the fix foundation model. However, in actual buildings with the pile foundation, sway and rocking occur in the span direction, which have a significant influence on the seismic performance. The purpose of this study is to investigate the effect of the vertical displacement of the piles on the response of superstructures. The paper showed that the base shear of the superstructures given by the soil-pile-structure interaction model was remarkably small compared with the fix foundation model, and that the tendency of a top heavy shape of the shear coefficient distribution along the height was significantly alleviated if the vertical displacement of the piles was taking into account.

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This paper deals with the analysis of corroded steel bar in concrete with emphasis on modeling the interaction between steel bar and concrete. The interaction of both materials is modeled by considering bond-slip relationships through the interface element. The model consists of a single steel bar and surrounding concrete using an axisymmetric model. Three types of bond-slip models are considered in finite element (FE) analysis; (1) bi-linear; (2) bi-linear with bond softening; and (3) tri-linear model. The input parameter of bond-slip model including maximum local bond stress, bond stiffness and bond softening is evaluated by degrading the bond and concrete tensile strength due to corrosion of steel bar. The models are assessed by comparing the FE analysis results with the experimental results of corroded tension members. From the analysis results, the tensile strength of concrete besides the maximum local bond stress and the bond stiffness give a significant effect on tension stiffening and cracking behavior.

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Two full-scale steel moment-resisting frames were constructed and tested at E-Defense to examine the performance of high-rise buildings subjected to long-period ground motions. Frame 1 adopted typical design and detailing from the 1970's employing both field-welded and shop-welded details for the moment frame connections. Frame 2 was identical to Frame 1 except that all connections were field-welded and upgraded using three strengthening methods. A number of connections in Frame 1 fractured during a simulated longperiod motion. No damage was observed in Frame 2 until the same motion was repeated multiple times. The performance of field-welded connections in existing high-rise buildings and the effectiveness of upgrade methods are discussed.

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In this paper, comparative parametric analyses with fishbone shaped model considering strength deterioration of members are conducted in order to investigate the complete collapse behavior of steel moment frames. COF and widththickness ratio et al. are adopted as parameters. In a lot of cases, the collapse mechanism varies from the total collapse type to the story-collapse type due to strength deterioration by local buckling. The analytical results show that the collapse mechanism at the time of the complete collapse affects the energy capacity. Furthermore, the methods to estimate the capacity using the results of pushover analysis are proposed.

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We develop a method for evaluating the amount of energy that a masonry wall can absorb during an earthquake, based on the amount of masonry wall deformation caused by an input acceleration that exceeds a critical degree of acceleration.In this paper, the rotational displacements of masonry walls concerning such variables as slope angles, friction angles between stone blocks and back fill soil and input acceleration were calculated. As rotational displacements of masonry wall models show good agreement with calculated rotational displacements of the wall, validity of the theory for predicting rotational displacements of the wall is clarified.

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The purpose of this research is to clarify the effect of cross sectional size and shape on the uni-axial compressive behavior of concrete filled square steel tube (CFT) short columns. Compression tests of square CFT short columns with cross sectional size 400mm have been conducted. This paper first presents the test results concerning compressive strength, and discusses the evaluation of the strength of square CFT short columns considering the effects of cross sectional size and shape. As a result, following have been found. i) effects of cross sectional size and shape on the square CFT short columns were clearly observed, ii) the compressive strength of various size square CFT short columns can be predicted by proposed numerical formula.

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The reports of building characteristic measurements in huge earthquakes show that viscous dampers are useful to reduce building acceleration. The formula of those damper characteristics is often relative to velocity in analysis. However the latest studies have shown that they depended on not only frequency and strain but also velocity. This means that analysis using the formula cannot always lead to exact results. Part 2 of this thesis showed the model of viscous fluid material properties under small strain, and it was not complex because it depended on frequency. This thesis proposes a model of the material affected by frequency and larger strains.

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Main purpose of this paper is to describe the relationship between slenderness ratio of the steel brace in the Buckling Restrained Brace (BRB) and stiffness of the cover. For the objective, contact analysis of the finite element method is applied to deal with behavior of the steel brace such as transition of mode from lower to higher-order mode. Several examples of the BRB, of which slenderness ratio distributes from 135 to 360, are analyzed. The obtained results are verified through actual experiments. Based on the obtained minimum required stiffness of the covers, relationship between the slenderness ratio of the steel brace and the strength of the cover is analytically formulated.

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Mixed structures composed of R/C (Reinforced Concrete) columns and steel beams can accommodate larger building spaces, whereas the R/C columns may be subjected to severe thermal stresses due to the thermal elongation of long span steel beams in a fire. In previous paper, results of load-bearing fire tests of sub-frames of the mixed structure indicated that the fire resistance of R/C columns is reduced by covered concrete spalling and forced horizontal displacement at the top of the columns due to thermal elongation of steel beam. In this paper, results of thermal stress analysis of these tests are presented and the influence of the concrete spalling and the action from the beam on the fire resistance of R/C columns is discussed.

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A series of experiments are conducted for the establishment of the predictive method of the structural fire resistance of heavy hardwood (Zelkova), column normally used for traditional temple buildings. The experiments consist of
(1) Measurement of the Young's modulus of Zelkova at elevated temperatures
(2) Measurement of charring velocity and internal temperature of large size Zelkova column exposed to ISO834 Standard Time temperature curve.
(3) Full scale tests for the validation of the predictive method of collapse time.
The experiments reveal only minor difference of the mechanical and fire-resistive performance between Zelkova and conventional softwood. The validation test has resulted in the predictability of the structural fire resistance of Zelkova column at roughly 10% over-estimate.

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