In recent years, use of low heat Portland cement is promoted. However, there was no general method to predict the strength development of the concrete using cement which has wide range of mineral composition. In low heat Portland cement, it was pointed out that application of “Maturity method” was difficult. We considered application of the equivalent age to predict the strength development of concrete using various type of cement. Then, we examined the strength development of mortar using cement has wide range of mineral composition under different curing temperature. As a result, the temperature dependency of strength development of various cements was explained by the equivalent age. The values of the apparent activation energy of cement were dependent on its mineral composition.

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We determined the air permeability coefficient of coating materials for textured finishes by the double chamber method and carbonation depth on the existing structure where years since construction passes. And we verified the application to the presumption method of carbonation depth of coating materials for textured finishes based on air permeability coefficient. As a result of this, it was confirmed that we can presume the carbonation depth of a concrete which is given coating materials for textured finishes with the diffusion coefficient and the carbonation resistance from a measured result of air permeability coefficient, even if that coating materials for textured finishes degrades. In addition, the study demonstrated that the carbonation progress of concrete with a coating materials for textured finishes can be predicted precisely, using the presumption method of carbonation progress by the air permeability coefficient considering the aging of coating materials for textured finishes.

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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. We examined two tests, the first test is water leak test by using semi-full sized specimen with actual components, and the second test is water leak test by using small sized specimen with the weakness points of this waterproofing system. As a result of the first test, separators and damaged parts are the weakness points of watertightness of this waterproofing system. For the second test, there is deference of watertightness of the specimen between vertical casting concrete and horizontal casting. When the concrete is casted vertically, there will be made air space under separators or rough composition of concrete near waterproofing layer and the water from outside will infiltrate easily if it penetrate through waterproofing layer. So it is necessary for the evaluation method of this waterproofing system to make specimen made of vertical casting concrete.

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Temperature and distortion of an existing wall sample were measured to determine how solar heat affects tile finishing and the base aside with heating-cooling repeat test on lab specimen to examine how adhesive strength falls.
In outdoors, wall temperature rose by solar heat caused distortion between tiles and concrete, which expand in different degree. In year-round fluctuation, contraction under declining temperature caused relatively similar gap. In this test method, major cause of decrease in adhesive strength turned out to be the distortion gap caused by water absorption expansion of the concrete.

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A series of shaking table tests on indirect-direct integrated health monitoring of pile foundations have been carried out for the purpose of detecting global and local damage during their service life. Different damage conditions of pile foundations are simulated. A limited number of acceleration sensors are placed on the roof and base of superstructure, whereas a number of strain sensors are attached to all piles at different depths. In the indirect health monitoring, the changes in transfer functions related to soil-structure interaction due to damage are investigated to detect global damage of piles. In the direct health monitoring, on the other hand, the changes in strain distribution of each pile due to damage are investigated to detect local damage of piles. Based on the experimental results, the feasibility of the real world application of the proposed method is discussed.

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In this paper, we analyzed the damage of reinforced concrete buildings due to the 1923 great Kanto Earthquake in the City of Tokyo based on the dynamic analysis of a specified building that was studied in the damage investigation reports. Earthquake response analysis was conducted using the restoring force characteristics of the building at that time. Seismic ground motion predicted at the building site for the 1923 great Kanto Earthquake was used. As a result, the relationship between the damage criteria by investigation reports and damage analysis data confirmed that the analysis method was useful to estimate the damage and seismic performance of the reinforced concrete building at that time.

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To investigate effects of nonlinear soil-structure interaction, we study the influence of the nonlinearity of pile damage on building response. In this paper, it is presented that the results of the centrifuge tests considering elasto-plastic behavior of pile and its simulation analysis. The following conclusions were obtained: (1) The response of the building, which is calculated considering the nonlinear characteristics of pile damage during the main shock, is smaller than that of the building which is calculated without the nonlinearity of pile. (2) In frequency transfer function between the ground and the building, the reduction of predominant frequency is mainly caused by the nonlinearity of the soil around piles. (3) The nonlinearity of pile damage has a very small effect in the building response in aftershock.

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We present the concept of correction-factor model of rupture directivity and radiation pattern for empirical attenuation relations of peak ground velocity and acceleration response spectra. Approximate radiation pattern coefficients derived from accurate coefficients is used in this model. In addition, directivity function of bilateral line source by Boatwright (2007) based on directivity function of unilateral line source by Ben-Menahem (1961) is used in this model. The proposed correction-factor model for fault-normal and fault-parallel components has physically-based predictor variables and applicable to broadband distance from near-source to regional distance less than 200 km. We estimate regression coefficients of the model for strike-slip and dip-slip faultings using strong motion records of six crustal earthquakes with Mw>6.0 and verify the model by simulating the observed records.

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This paper presents a simple design method for tuned dynamic mass systems, which are adjusted by a concept of pseudo mode control. The intension of the pseudo mode control is to make the target structure practically behave as a SDOF system by suppressing the growth of a few higher modes such as the second mode and the third mode. Since giving high viscous damping has a tendency to stimulate the growth of higher vibration modes, the optimum damping tuning is decided by comparing the effect of mode control with the magnitude of the viscous damping factor on a basis of the invariable point theory for a SDOF system. The paper shows that the presented structure system is able to hold the viscous damping factors more than 0.15, when the auxiliary stiffness factor defined by the invariable point theory is controlled more than 1/1.5.

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To assess the long-period (1-15 sec) ground motion has become a critical issue associated with a recent rapid increase of tall buildings, base-isolated structures, long-span bridges, large storage oil-tanks and so on. We obtained empirical models of 5% and 1% damped acceleration response spectrum for long-period ground motion on hard rocks. We only used the down-hole data of the KiK-net at 161 selected hard rock sites where the S-wave velocity exceeds 2.0km/s at depth of down-hole. We used the 2,078 records from larger magnitude than 5.7 and events shallower than 60km. Considering the quality of data, the records of shorter distance than 500km were used. In addition, we verified validity of our empirical predictive model by comparing with the observed individual strong ground motion records.

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Under large earthquakes, the first floor columns sustain severe damage and these damages may cause collapse in the first floor. To decrease the damage of the columns, free standing structures whose first floor columns are not fixed are a choice. The seismic response of the structure is greatly influenced by the kinematic friction at the base. This paper studies the kinematic friction between steel and mortar, which are widely used in construction. Two shaking table tests were conducted by putting a rigid structure or flexible structure on a mortar base. The test results showed that stick-slip phenomenon changed the kinematic friction greatly. A parametric study for a free standing structure subjected to ground motions showed that types of kinematic friction affected the sliding displacement, but it was not so influential to the damage of structures.

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In this paper, we propose two simplified methods for foundation input motion of embedded foundation. The first is the least squares method based on the geometrical relationship between each part of the foundation and ground motion. The second is the weighted average method which uses the simplified evaluation for the driving force and impedance function of embedded foundation by combining the impedance function of spread foundation and ground motion. The accuracy and validity of the proposed methods are shown by comparing the results with those obtained from an existing numerical method.

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The structural-seismic safety is evaluated by the amount of plasticity energy. The prediction method based on energy balance has been established, and this method is founded on simplified shear spring model. In case of the vibration control structure having the hysteretic dampers, the shear spring model excessively evaluates the efficiency of the vibration control of the dampers because the effective damper deformation is not considered.
In this paper, the shear spring model considering the effective deformation of the hysteretic damper is made by connecting the series spring to the damper. This series spring can be obtained without the push-over analysis of the material model. In addition, the prediction method based on energy balance considering the effective damper deformation is proposed.

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The main purpose of this study is to form an evaluation method of the ground motion caused by an earthquake on the basis of the energy balance concept through pseudo dynamic tests. In this paper, the following two facts are made clearly stated in order to form the evaluation method: 1) The ratio between the viscous damping energy and the energy input can be evaluated by the previous equation proposed for frame structures using the viscous damping ratio. 2) The energy distribution of each layer is stabilized after the shear strain reaches the reference strain. The energy distribution ratio can be evaluated using the following three items: A) the initial effective confining stress, B) the damage level which is obtained by the first mode of the ground stratum and displacement response spectrum, C) the reference strain that shows the ductility of the ground material.

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Experimental studies on quantitative load-settlement relationship have been well presented, which were carried out with vertically loaded spread foundation on sand ground. However, mechanical properties regarding the relationship have not been theoretically understood. In the previous paper, we elucidated experimentally and theoretically the mechanical properties on dense sand ground. The present study provides the analysis of mechanical properties on loose ground through similar model experiment to the previous one. Under about 15% of the range in a ratio of settlement to the diameter of footing, load-settlement relationship was found to be successfully analyzed through FEM simulation with SMP-Cam-Clay model which was estimable of the negative dilatancy of sand. The FEM simulation reveals that under the range 1.3%, the sand ground under footing exhibits contractile behavior with negative dilatancy, while between 1.3 and 15%, sand behavior undergoes shifts from contraction to contraction and subsidence with slip line directly below edge of footing. Over about 15%, the FEM simulation was apparently not applicable for the analysis of load-settlement relationship and load-settlement relationship shows a good agreement with the subsidence characterized by bearing capacity based on Terzaghi's theory.

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In the seismic safety evaluation of the nuclear power plant, the reasonable specification of the limit performance is required.
The purpose of this study is to clarify the limit performance of large span roof truss at nuclear power plant, for advanced evaluations. First, in this study, the static loading test of large-scale specimens, that imitate real roof truss, is done. Then, behavior and deformation capacity of roof truss in large deformation area are examined. And by analytical method, the correspondence of the damage of truss member and whole behavior is confirmed. In addition, a useful evaluation method of ultimate limit of roof truss is proposed, and the validity of proposed method is confirmed by the test evaluations of some roof truss models.

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The purpose of this study was to elucidate the behavior of moment resistance timber frame(“frame”) under vertical load and to determine that structural performance can be evaluated by numerical analysis.“Frame” was experimented by applying horizontal force while it was loaded with vertical load. From experiment and numerical analysis of “frame”,shear strength and shear stiffness varied by vertical load.The results of the study suggest that structural performance of “frame” when vertical load and horizontal force are applied at the same time should be evaluated by giving due consideration on the influence of vertical load.

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Although timber structures are advantageous for their cost and fabrication, there is a difficulty in obtaining large members and assuring strength in joints. Composite section members with steel plates sandwiched with timber sections can overcome these disadvantages; however, an effective method is required for their connection. In this research, a simple shear (friction type) connection using torshear-type bolts is developed and the connection properties are experimentally examined. Also, the buckling strength of the composite members is analytically evaluated using the obtained test data. Furthermore, relaxation of the bolt tension due to drying shrinkage and creep in timber was examined for 180 days.
The initial shear stiffness of the connection (tested one day after bolting) is 50-75kN/mm, while the first peak strength is greater than 20kN. The relaxation of the stiffness is limited (the initial shear stiffness is 57-86kN/mm, and the first peak strength is 29-43kN); however, the tension in bolts and the peak strength are degraded to 20% and 40%, respectively. Analytical evaluation reveals that the connection failure does not control the buckling strength of the composite members.

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This paper describes the effectiveness of pre-repairing on total repairing cost prepared against earthquakes based on the seismic diagnosis and the seismic retrofit of thirteen existing wooden houses. We investigate the damage level by means of the relative displacement between upper and lower floors obtained by time-domain response analysis. The main results obtained from the investigations are as follows.
We show the regression equation between the pre-repairing cost and the disparity evaluated by seismic diagnosis of before and after seismic retrofit. After suffering the seismic damage, the necessary repairing cost of un-repaired house is about two to six times than that of pre-repaired house. This shows the effectiveness of pre- repairing on total repairing cost against earthquakes. Houses which evaluated low mark by seismic diagnosis have more effectiveness on total repairing cost.

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This paper proposes an accurate, member-by-member analytical model for timber structures having energy dissipation walls and/or plywood shear walls. Various member joints are modeled by using nonlinear spring elements whose properties derived from numerous test results, and model's schemes are described in detail. The analyses were found to reproduce both local and global responses obtained from cyclic loading tests and shaking table tests of a variety of one-story mult-span timber frames. Moreover, difference between single wall and linked walls, difference of seismic response by variation of damper and nail volume are discussed.

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The objective of this paper is to estimate shear strength of seismic retrofitted RC column by extended wing walls connected by post-installed anchors. The experimental variables are vertical joint anchor ratio, shear reinforcement ratio in the column and wing walls. An evaluation method for the shear strength of seismic retrofitted RC column by extended wing walls is proposed based on arch-truss method. The calculated shear strength by this method is correlated with the experimental shear strength than the other previous methods. That result also show that the shear strength and initial stiffness of seismic retrofitted RC column by extended wing walls is higher according to increasing vertical joint anchor ratio.

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As for the prediction of nonlinear earthquake response of a single-degree-of-freedom system with Takeda's hysteretic model, the authors have proposed an equivalent linearization method based on the asymmetric steady state response, which gives the average value of the maximum responses obtained from the time history response analysis using twenty-five design input ground motions with random phase. In this paper, the variation of the maximum response from the average value is discussed in detail, and it is shown that the variation of the maximum response can be expressed by that of the symmetric ratio of response and that of the displacement amplitude. Finally, a method for the maximum response considering the two variations is proposed. The method gives good agreement with the results of the time history response analysis using the design input ground motions with actual phase of some observed ground motions as well as random phase.

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The purpose of this paper is to model mechanical properties of prestressing strand at elevated temperature for estimating the strength and deflection of prestressed concrete members during fire and/or after fire. Prestressing strands(SWPR7BL) of 12.7 mm in diameter were used as test coupons. Tensile tests on prestressing strands at elevated temperatures were conducted to investigate mechanical properties such as yield strength, Young's modulus and creep strain. Reduction in yield strength, Young's modulus and stress-strain curves at elevated temperature were formulated. Creep tests were conducted on prestressing strands. The initial stress applied was 70% of the yield strength. The maximum creep strain was as large as 545 microns at 250°C. Creep behavior of presstressing strands was approximated by a numerical formula proposed by Norton and Bailey. Using the formula together with time-hardening rule, an estimation method of relaxation of prestressing steel at high temperatures was proposed.

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In the seismic behaviors of the frames with fixed column bases, the soft story mechanism may occur when the frames are subjected to unexpected seismic horizontal force. This paper proposes the new columns support systems on the first story. The first story columns consist of the reinforced concrete downside column and the steel topside column, and their joints with the anchor bolts and the shear plates are supposed to be pinned. This paper clarifies the damage distribution and the seismic capacity for the steel moment resisting frames with these support system to perform the collapse mechanism which means the maximum story drift when the ductility demand reach the plastic deformation capacity for a member first.

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The weld defect of the welded beam-to-column joint in steel structure causes the brittle fracture and has possibilities to reduce the deformation capacity. It is considered that the effect of the weld defect on the deformation capacity from the difference of between shop and site welding beam-to-column joints is different. Therefore it is important to understand this difference.
In this paper, full-scale welding test was done it were shop and site welding beam-to-column joints. Then, the effect of the deformation capacity of test specimens caused by the difference of the position of welding defects between two joint methods was studied. As the results, the deterioration of deformation capacity caused by the welding defect was low using shop welding beam-to-column joints, and high using site welding beam-to-column joints.

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The authors conceived a buckling-restrained brace providing stable hysteretic characteristic even under high-strain conditions. In the past paper, conducting cyclically static loading tests, the performance evaluation formula of the buckling-restrained brace was presented. The many buckling-restrained braces in practical uses have weldings in the energy absorption area of the core plate. Brittle fracture might be caused, when the welding exists. In this case, the performance of the buckling-restrained brace decreases. In this paper, the specimens with different welding specifications and steel kinds are fabricated. Tensile loading tests are conducted as parameter of temperature. The tensile performance of the specimens with local welding and without welding is almost the same. The other hand, the performance of the specimens with continuous welding reduces.

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In general, single buckling model is applied to deal with buckling analysis of slender columns in complex frame in order to provide a handy method to evaluate buckling load and effective length. However, buckling behaviors of columns are affected by each other. The effect of coupled instability may be considerable especially in non-uniform frame.
This study aims to propose a parametric method to evaluate the buckling load considering the effect of coupled instability subjected to columns in braced frame. The correlation between single buckling and coupled buckling is revealed through theoretical analysis. The critical load of single buckling and coupled buckling are formulated based on the examination. In the process, the lower limit and upper limit of buckling load are found effective and important.

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The authors have developed a tensile force strengthening method using bonded carbon fiber reinforced plastic (CFRP) plate to enhance the life of existing buildings. Aging and deterioration of existing steel structures necessitates the development of simple and efficient rehabilitation techniques. To enhance the strength and plastic deformation capacity of steel structural member, it is required a rehabilitation technique for compressive force strengthening as well as for tensile force strengthening.
This paper reports the results of compression and cyclic loading tests conducted on an angle steel member before and after rehabilitation using CFRP plates. These results show enhanced axial force carrying capacity and plastic deformation capacity of the member by bonding CFRP plate and the proposed rehabilitation is effective for compression member of steel structure.

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Structural system composed of high-strength steel frame with energy-dissipation elements is one of the suitable solutions for damage tolerant structure. In this concept, the main structure is designed in elastic zone for design earthquake level; however, there are still some risks to step into plastic zone in maximum considered earthquake levels. Because of high strength steel having high yield ratio, it is concerned to fracture early after yielding. In this paper, following the mock-up cyclic-loading tests and analysis of 800Mpa steel beam-column frame with diagonal BRBs, their fracture mechanism of beam-end connections are modeled using simple non-linear rotation springs, and estimation method for their cumulative energy dissipation capacities until their fractures in multistory structures are proposed.

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In order to investigate shear and bending behavior of prestressed precast concrete (PCaPC) beams with high-strength rebars and multiple large openings, three specimens for PCaPC beams were tested. Test parameters are the level of vertical loading and the quantity of shear reinforcement. It was confirmed from the test results that PCaPC beams are able to resist the allowable permanent during 3 hours standard fire. The evaluation method for bending and shear strength of PCaPC beams at high temperature, as well as the results of the fire experiment will be presented. In this analytical method of shear strength, the truss mechanism across openings in addition to at opening and between openings was considered. This new shear strength mechanism is proposed to calculate with a good accuracy taking into account of the temperature of longitudinal and shear rebars.

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Social attention has gathered in BCP recently, a technical concern is to estimate the restoration time of facilities due to earthquake quantitatively. In general, facilities are modeled as a system composed of plural components, then the system reliability technique is used for the estimation of the restoration period of system function. However, individual performance of the component is not considered, there is a blind spot that a redundant performance of the entire system is not appreciable. In this paper, the evaluation method of the decrease in the system performance due to the earthquake is proposed considering an individual performance of the component and the damage correlation between components. In addition, the evaluation method of the recovery curve that can show the recovery process of the system performance is proposed. As an example of the manufacturing process, the case analysis are carried out, the applicability in this method is discussed.

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