Because of environmental consideration and variety of required performance for concrete, the kinds of constituent materials used for concrete have been increased. For this reason the bleeding of concrete has shown a high value in some cases. It is said that higher bleeding has some harmful effects on the properties of concrete and reinforcement but the method for control of bleeding have not been proposed.
 This paper presents the results of experimental study and the literature survey on the simple prediction model of bleeding of concrete.
 The experiment was composed of four series and the bleeding test of concrete was conducted in accordance with JIS A 1123 except for the interval of taking the rising water. In series 1, unit water content and the kind of chemical admixtures were varied under the constant water cement ratio. In series 2, the variation of bleeding in the different 7 batches was checked. In series 3, unit water content, water cement ratio and the kind of chemical admixtures were varied. In series 4, the variation of 7 bleeding test samples in the same batch was checked. Based on the series 2 a simple prediction equation of bleeding was established.
 And a literature survey on bleeding of concrete in Japan was conducted and the data of experiments in which unit water content or water cement ratio are varied under the other condition is constant were set in order.
 Moreover the comparison of the existing three prediction equations and the equation model of bleeding of concrete proposed in this paper was conducted.
 At the last stage the effect of bleeding in the cases in which this proposed equation was adapted to those using with other chemical admixtures were considered based on the data provided by some organizations, because the concretes using with air-entraining agent and air-entraining and water-reducing agent were treated in this experiment.

 The conclusions of this study are summarized as follows.

 (1) It was confirmed that bleeding amount reduces linearly with the reduction of unit water content or water cement ratio.
 (2) The data of variation in the different batches and that in the same batch were obtained, and in the latter case the variation of plain concrete was larger than that of concrete with air-entraining agent or air-entraining and water- reducing agent.
 (3) The prediction equation of bleeding considering unit water content and water cement ratio was established, and it compares favorably with existing equations.
 (4) The empirical constant coefficient in the prediction equation of bleeding had wide range of 3 or 4 times due to the lots of used materials even if the brand or district was the same. In other words, it was found that bleeding mass had the same range. Accordingly, it is necessary to study the influence of the quality of cement and fine aggregate on the empirical constant coefficient in the future.
 (5) In the case where chemical admixtures were used, the coefficients which multiplies the empirical constant coefficient of plain concrete were shown in each kind of chemical admixture. The compatibility of experimental values and calculated values in the case of air-entraining and water-reducing agent or air-entraining and high range water-reducing agent was not so good compared to air-entraining agent or water-reducing agent.

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 It is expected that elderly people can't remove snow on their own, and have a trouble going out. There are some ways to remove snow which do not require physical effort, but each conventional way has problems.
 Therefore, the authors have attempted to invent the “heating mortar block system” to remove snow. In this system, electromagnetic waves are generated by the oscillator, and then irradiated mortar blocks with. A heating mortar block is composed of 3 layers; 1. electromagnetic absorption material 2. base material (without electromagnetic absorption ability) 3. electromagnetic shielding material. Electromagnetic absorption material placed near the surface absorbs electromagnetic waves and converts it into heat. This system uses this heat to melt snow on the blocks. Electromagnetic absorption material is mortar mixed with electric arc furnace oxidizing slag as aggregate (hereinafter, called “the slag mortar”), and base material is a mortar mixed with sand as aggregate (hereinafter, called “the sand mortar”).
 According to preceding research, there is a correlation between abilities of electromagnetic absorption and heating. But, the characteristics of electromagnetic absorption and heating about electromagnetic absorption material composed of the slag mortar and the sand mortar has not been studied enough.
 So, the purpose of this study is to clarify these things and develop the base theory to design heating mortar blocks absorbing the electromagnetic waves and heating well. Ability of electromagnetic absorption is evaluated with return loss calculated by S-parameter method.
 Within the measuring range, following things were clarified.
 (1) When the sand mortar is superposed under the slag mortar, the thickness of which the sand mortar causes the prominent absorption of electromagnetic waves at specific frequency (hereinafter, called “peak”), has a period. And, it is possible to choose a thickness from some thickness by considering this period.
 (2) When the sand mortar is superposed under the slag mortar, it is possible to determine the thickness, by specifying the thinnest thickness through the experiment and using the equation produced in this study.
 (3) It is possible to adjust the temperature rises of the heating mortar block without changing the thickness of the slag mortar which is the electromagnetic absorption material, by just changing the thickness of the sand mortar.
 (4) When the thickness of sand mortar superposed under the slag mortar is 30mm, 62mm or 93mm and it is irradiated with electromagnetic waves of frequency 2.45GHz, the temperature rises 20.6 °C, 17.3 °C or 19.2 °C each. In these thickness, return loss also rise as a peak.
 (5) When the sand mortar is superposed under the slag mortar, it is possible to evaluate the heating ability by return loss.

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 In February 2014, owing to heavy snowfall in the Kanto-Koshin region, several buildings were severely damaged. A major cause for the damage was the load on building surfaces caused by heavy snow followed by a surcharge load due to the ensuing rainfall. Countries such as the United States and Canada have established standards on snow loads, which also take into account the surcharge load due to rainfall. In contrast, Japan has not adopted such standards, and hence it is imperative to establish a method for calculating loads added by rainfall to snow loads. Therefore, in this study, experiments were conducted using artificial rainfall on roofs covered with snow to evaluate and propose a calculation method for loads added by rainfall.
 First, outdoor experiments as well as indoor experiments in a low-temperature experimental facility were conducted. Model roofs with different span lengths and gradients were built and loaded with natural and artificial snow. These model roofs were then treated with rainfall at constant intensity by using an artificial rainfall simulator. The increase in load was measured and several observations were made from the experiments. A smaller roof gradient and larger roof span resulted in a greater peak value of the load added by rainfall. For roofs of the same shape, the peak value of the load added by rainfall increased as the initial snow depth increased. Next, the relationship between surcharge loads due to rainfall and the span length and gradient of the roofs was quantified. The load added by the rainfall was treated as the approximate square root of the snow depth, and a coefficient a, which depends on the span length and gradient of the roof, was defined. However, valuable data were obtained from the experiments for only five types of roof geometries. To estimate the values of the coefficients a for other roof geometries, regression analysis between the coefficient a, roof gradient, and span length was conducted. Comparing the surcharge loads, which were calculated using the estimated coefficients a, with the loads calculated using the O'Rourke equation, a relatively good correspondence between both the results was confirmed.
 Snow loads that take rainfall into account were obtained for the given regions with corresponding values of the design snow depth. This was achieved by including the load due to rainfall, which is correlated to the snow depth, computed from the proposed formula and the estimated coefficients. In addition, methods that include coefficients reflecting the regional climatic conditions were proposed. One such method is based on the fact that winter rainfall is not always observed during the period when the deepest snow cover occurs. Extreme values of the snow depth were obtained from the meteorological data to derive the ratio of snow loads on rainy days against the maximum winter snow loads; the ratio was treated as the coefficient k1. Another method considers the regional meteorological cases wherein the surcharge load due to rainfall does not reach the peak value. The ratio of the surcharge load value due to such rainfalls against the surcharge load calculated by the proposed formula was treated as the coefficient k2. However, because the influence of coefficient k2 is relatively small, it can be considered as 1 in practice. Moreover, because the impact of loads added by rainfall is relatively small in heavy snowfall regions, the regions where it is necessary to consider the loads due to rainfall may be limited to general regions where the design snow depth is 1 m or less.

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 1. Introduction
 Although the performance of seismic isolation devices such as rubber bearings or dampers have been tested and evaluated through unidirectional input, in fact these devices are subjected to seismic ground motions in two direction. Recently the performance of high-damping rubber bearings under bidirectional input is found to be different from that under unidirectional input, and bidirectional tests for various isolation devices are being carried out. In this paper, bidirectional shaking table tests for SSB (Spherical Sliding Bearing / Friction Pendulum Bearing: FPB) are conducted, and the difference of their response against unidirectional response are investigated. Bidirectional effects are discussed using analytical model taking these testing results into account, followed by the studies on the effects on the response of supported superstructures.

 2. Bidirectional shaking table tests for a single SSB
 Bidirectional shaking table tests for a single SSB are carried out. A mass gives dead load 24.3 N/mm² pressure on a sliding bearing surface of the SSB, expected friction coefficient is calculated as 0.056, and natural period after slipping is 4.5 sec. As a result, the maximum response displacement of the SSB under bidirectional input is larger than that under unidirectional input, and acceleration is same level between both inputs. These differences are considered to be caused by the bidirectional effects of friction force vector.

 3. Response of multistory frames supported by SSB under bidirectional input
 The response obtained by the shaking table tests is compared with numerical analytical results with a friction pendulum model (FP model) which taking account of pendulum action and bidirectional effects of friction force vector proposed by the authors. The FP model well explains the difference of response under bidirectional vs. unidirectional input. The response of multistory frames supported by the SSB is also studied, and excitation in the displacement response and reduction in the acceleration response are observed.

 4. The effects of hysteretic models on the bidirectional response
 In this chapter, the bidirectional response effects of the FP model and ordinary MSS model (Multiple Shear Spring) which does not simulate pendulum action and has different bidirectional effects of friction force vector are discussed. As a result, the bidirectional effects of friction force vector are significant during the post-sliding frictional stiffness decreasing. Also the effects of normal reaction forces are remarkable, which are not caused by the overturning response of the superstructure, but mostly by the pendulum actions.

 5. Conclusions
 1) The maximum displacement response under bidirectional input generally becomes larger than that under unidirectional input, while acceleration response generally keeps independency between unidirectional and bidirectional input. These bidirectional response characteristics of the SSB are well explained with the FP model.
 2) In multistory frames supported by the SSB, displacement response increases in each story while acceleration response in the upper story decreases by additional bidirectional input compared with unidirectional input.
 3) Using a SSB with large spherical radius, the response by the MSS model differs from that by FP model. That is mainly because MSS model has different bidirectional effects of frictional force vector. On the other hand, the effects of nominal reaction forces become remarkable in the case of using SSB with small spherical radius, which is mainly caused by pendulum action.
 4) The proposed FP model including the pendulum action is considered to be more suitable for evaluate the response characteristics of SSB discussed above than MSS model.

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 Since seismically isolated (SI) buildings are thought to be fragile when subjected to extreme input ground motions beyond design level, various measures such as shock absorbers on moat walls and stoppers put in isolation level have been developed. Those technologies should be helpful to increase seismic safety margin of SI buildings, while they cannot avoid the damage to moat walls, superstructure, or isolation devices. In this paper, the authors propose a new lead rubber bearing (LRB) which has much higher seismic safety compared to general isolation bearings including conventional LRBs.
 The proposed bearing named “FSLRB” or “Fail-Safe LRB” consists of a conventional LRB and a newly developed slider system in series. Friction factor of the slider system is optimally provided to start sliding just before LRB gives a hardening property with the shear strain of around 250%. Then, the bearing behaves as a general LRB which is just friction connected to the building structure at either of upper or lower end, when subjected to design level earthquakes or smaller, while the sliding behavior keeps LRB away from hardening and shear break in severe earthquakes beyond expectations. Hence, supporting a superstructure only by the proposed bearings will enable the whole SI building to protect from any structural damage regardless of the input ground motion levels. A preliminary time history analysis for two SI building models, one applying only FSLRBs, the other applying only conventional LRBs, shows the advantages of the system with the proposed bearings.
 Realizing the above high seismic performance, firstly the most suitable slider material, which was a certain PTFE, was selected by conducting a series of dynamic loading test for each combination of stainless steel plate (SUS304) and 12 candidate slider materials. A dynamic loading test of a scaled FSLRB applying the selected PTFE showed that the bearing almost behaved as expected in the preliminary time history analysis. Dynamic and static friction factors were evaluated as well as surface pressure and velocity dependence of those two factors were formulated from the test results. Furthermore, a full-scale FSLRB was tested under a rather high compression force with quasi-static horizontal loading, to investigate the maximum allowable conditions regarding surface pressure and the second shape factor of LRB part. Finally, a detailed time history analysis of a FSLRB building model was conducted. As for the analysis model, 256 full-size FSLRBs with the mechanical properties evaluated in the above loading tests supported a deformed nuclear power plant consisted of a reactor building and a turbine building set on a common isolation raft. The analysis result showed that the superstructure remained elastic and the maximum responses were lower than design criteria even when subjected to a long-period ground motion beyond design level. On the other hand, it became clear that both the maximum deformation and residual deformation at isolation level were much larger than conventional LRB building model.
  From the above development and analyses, it can be finally concluded that an SI building applying the proposed bearings can realize much higher seismic safety compared to conventional SI buildings, if only provided a large enough isolation gap considering the maximum considered earthquakes.

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 1. Introduction
 Pile foundation response during earthquakes is strongly affected by nonlinear soil-pile foundation interactions. The damages to pile foundations during the 1995 Hyogo-ken Nanbu Earthquake and the 2011 Tohoku-Chiho Taiheiyo-Oki Earthquake were obviously attributed to nonlinear interactions of soil-pile foundation-superstructure. In addition, the vibration properties of soil and superstructure made the damages complicated. Therefore, in order to sophisticated seismic evaluation of the pile foundation, the nonlinear lateral soil resistance around pile should be properly evaluated and it should be incorporated in the seismic response analysis model. However, only few studies have been reported on the evaluation method of the nonlinear lateral soil resistance around pile. Therefore, the purpose of this study is to propose the simple formula to calculate the initial stiffness and the nonlinear lateral soil resistance around pile. The parameters of the simple formula are the shear wave velocity, the internal friction angle and the diameter of the pile. An additional purpose is to propose the simple formula to calculate the group factor of the nonlinear lateral soil resistance around pile for integrated pile model.
 2. Method
 In this study, the nonlinear lateral soil resistance around piles is calculated using the soil-pile system modeled by 3D-FEM. When calculating the soil spring around piles, the piles are modeled as excavated soil and uniform forced displacement is given to the whole of the piles. The soil springs that are calculated are normalized in the diameter of the pile and the shear stiffness. The normalized soil springs are then approximated using a second-order logarithmic function. From the relationship between coefficient calculated by approximation and the internal friction, the simple formulas are determined. The group factors of the soil spring for the integrated pile model are calculated. The integrated pile model is, obtained by modeled as one pile which has integrate the mass and stiffness of all piles. The simple formulas are determined from the relationships between the group factor and two of the influencing factors. Two of the influencing factors are the number of piles and the spacing of the piles.
 3. Conclusions
 The major findings obtained from this study are summarized as follows:
 (1) The simple formula for determining the initial stiffness of the soil spring is shown in Eq.(4).
 (2) The simple formula for determining the nonlinear lateral soil resistance around pile is shown in Eq.(5) and Eq.(8). The soil spring defined in the simple formula correspond to soil spring calculated by 3D-FEM.
 (3) The simple formulas for determining the group factor of the soil spring for the integrated pile model are shown in Eq.(10), Eq.(11) and Eq.(12). The group factors defined in the simple formula correspond these calculated by 3D-FEM.
 (4) The calculation formulas proposed in this study are greatly useful in modeling pile foundation for the seismic response analysis.

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When lattice shell roofs with a rise are subjected to horizontal ground motions, coupled horizontal and vertical responses are dominated, and the responses are complicated to estimate. The authors have proposed simple evaluation methods of spherical domes, cylindrical shells, and freeform lattice shells for computing the responses by use of equivalent static loads. However, these evaluation methods are examined for shells and domes constituted only by a positive curvature. This paper presents a response evaluation method of shells with a positive and negative curvature by applying the previously proposed method. This kind of shell is dominated by two main eigenmodes: bending mode with pin supports, and swaying mode with roller supports. Results of the response evaluation method using the equivalent static loads are provided by comparing the complete quadratic combination (CQC) method.

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 Recently, buildings or its components are starting to be constructed by 3D printer¹⁾. In the near future, if such technology progress, buildings with various forms will be constructed. On the other hand, topology optimization method (software) is becoming widespread as a method to create a structural form with mechanical rationality. Also, topology optimization method has high compatibility with digital fabrication technology, and this method is adaptive for developing new form of buildings or its components⁵⁾.
 In this paper, we focus on façade design of buildings used prefabricated walls, and we propose a method to design the prefabricated wall using topology optimization method. In this method, artificial design elements are added to the topology optimization method. In this paper, 2-axis symmetry and continuous pattern conditions are adopted as the artificial design elements. IESO (Improved Evolutionary Structural Optimization) method^2,3) is used for the topology optimization method. IESO method is improvement of initial ESO method⁹⁾, and in this method, benefits of BESO⁶⁾, Extended ESO⁷⁾, and CA-ESO⁸⁾ methods are combined.
 In section 2, the outline of IESO method is shown. In this method, the design domain is divided in same eight-node brick elements (voxels), and in the optimization process, for solid element, it will be removed if the sensitivity number is less than the threshold value. This threshold value is obtained from the equation which consists of the mean value of sensitivity number and the average deviation of sensitivity number with a control parameter. In this method, the evolutionary volume ratio (reduction ratio) is given as an input data, and this control parameter is determined automatically in the program so as to satisfy the given reduction ratio approximately. Furthermore, in this method, finishing algorithm is added. In this algorithm, first, the converged solution obtained by IESO is input, and then, the elements about 5% of the total elements of design domain are added according to the rule of CA method. And the calculation of IESO is executed again with the smaller reduction ratio than the initial analysis (about 1/5～1/10).
 In section 3, the methods for adding the artificial design elements (2-axis symmetry and continuous pattern conditions) are shown. Also, the finishing algorithm is improved. In the new algorithm, if the sensitivity numbers of elements are greater than the average, the elements of the von Neumann neighborhood are added. This finishing algorithm is repeated until a clear solution is obtained.
 In section 4, the numerical examples of computational morphogenesis of prefabricated wall are shown in order to verify the application possibility of the proposed method to the façade design of buildings used prefabricated walls. Fig. 5, 6 show the results of analysis with 2-axis symmetry condition. Fig. 7, 8 show the results of analysis with 4-continuous pattern condition. Fig. 9, 10 show the results of analysis with 2-continuous pattern condition. Fig. 11～16 show the façade design image of buildings using the results obtained Fig. 5～10.
 It is concluded from these numerical examples as follows.
 (1) In the voxel finite element method, it is easy to give the 2-axis symmetry condition or the continuous pattern condition, because the arrangement of the elements (voxels) is uniform.
 (2) The clear and simple solutions can be obtained by application of the improved finishing algorithm.
 (3) The solutions with more robust form can be obtained by addition of the 2-axis symmetry condition or the continuous pattern condition.
 (4) Façade designs created from the solutions are not uncomfortable even if these are used for apartment houses in urban areas.

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 Based on many reports that have been already published for experiments of mud wall subjected to cyclic loading, a method to make envelope curve is proposed here by statistical studies. The walls for the examination are full-scale mud walls of about 1.8m width and all of both sides of the wall are plastered without final coat.
 The main observation from this statistical investigation of the database is as follows.
 (1) The average of maximum strength is about 15kN at 1/52rad. The average of strength reduction is about 41% of the maximum strength at 1/15rad and about 47% in 1/10rad. The average of ultimate strength of Elasto-Plastic Model is approximately 88% for the maximum strength.
 (2) In this data, we found a gradient of secant in a specific shear deformation angle of wall has a considerably strong correlation with the gradient in the next specific angle.
 (3) We suggest an estimation method of the envelope curve of the mud wall by statistical studies. After the strength of the wall in a small deformation is evaluated by using the compressive strength of wall clay, the envelope curve is predicted by a specific gradient of secant and the above correlation coefficients. Finally, the estimated envelope curve of the mud wall predicts in large deformation until 1/10rad. This envelope curve has the deteriorate state.
 The same procedure enables to make envelope curve in Kyoto. As a result of having estimated the envelope curve of the Kyoto mud wall, it is as follows.
 (4) The envelope curve of the Kyoto mud wall can be estimated by applying the correlation coefficients of the experimental data of the Kyoto mud walls. The estimated curve of the Kyoto mud wall gives a considerably good approximation of experimental curves that force deteriorates in large deformations.
 (5) When the envelope curve of the mud wall which have the local specification is estimated, it is enabled even to gather up more than three experimental data, but it may be estimated result more than the experimental value in large deformations. The envelope curve of the local mud wall could be more appropriate by increasing experimental results in the database.
 (6) The strength difference is about 40% between experimental results and the estimated results.

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 The important structural elements of traditional timber structures in Japan are rotational resistances of column-beam joints. The restoring forces characteristics of their structures depend on the rotational resistances of the joints. Therefore, the elasto-plastic restoring force characteristics of embedment of joints are the most significant in order to evaluate the seismic performances of traditional timber structures.
 The authors have already made clear the embedment mechanism of crosspiece joint which is the most basic and their rotational center is easily understood, and formulated the elasto-plastic restoring force characteristics of embedment of joints by using Elasto-plastic Pasternak Model (abbreviated to EPM).
 However, there are many types of joints and their resisting mechanisms may be different. The crosspiece joint is the most simple and basic because of the symmetry in rotational mechanism. The formulation of restoring force characteristics of T-type joint including Sashikamoi has not been made because it is difficult to find the rotational center. Of course, it is possible basically to find the rotational center based on the geometrical and force conditions. However, the solution is complicate and it is difficult to express the position in a closed form.
 Therefore, the authors assume the rotational center by T-type joint loading test results, focusing on the movement of the center of joint and rotational center. They assume the rotational center on the surface of Nuki (Fig. 11) and under the edge of Sashikamoi (Fig. 12). Then, the restoring forces characteristics are formulated based on the EPM, and parameters are determined in order to trace the restoring forces characteristics of the test results.
 The loading tests are carried out as follows; The test setup is shown in Fig. 2. The column is made of steel and test specimens of Nuki and Sashikamoi are made of Japanese Cypress. Nuki consist of A, B, C, D, E, F and G types and Sashikamoi are S and K as shown in Fig. 3 and Table1.
 The test results of joints are shown in Photo1～Photo4. The movement of the center of joint A-2 and S-2 are shown in Fig. 6 and Fig. 7. Then, the rotational center C is searched from the geometrical relation between the center of joint and rotational center. Distribution of the rotational center C is plotted in Fig. 9 and Fig. 10. As a result, the rotational center C mostly situates on the surface for Nuki, and under the point V for Sashikamoi.
 Thus, the authors assumed the position of the rotational center and rotational embedment models are shown in Fig. 11 and Fig. 12. The EPM formulation of the Nuki and Sashikamoi are proposed in equations from (4) to (36). The restoring force characteristics of test results are simulated based on the EPM formulation and obtained the EPM parameters as shown in Table2 and some examples of simulated results are drawn in Fig. 13～Fig. 16.
 As a conclusion, the simulated results of M-θ relations are fairly well comparing with the test results and the proposed formulations are confirmed to be adequate.

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 Small detached wooden houses typically have eccentric arrangement of shear walls, which results in torsional vibration when subjected to earthquake. In addition, flexible floor diaphragm of wooden structures complicates the dynamic behavior. Since eccentricity ratio, which is originally defined in Japanese Building Standard Law, is a simple index to confirm adequacy of arrangement of shear walls, such a complicated behavior is not accurately simulated.
 In this paper, index of torsion taking dynamic effect and flexibility of floor diaphragm into account is proposed based on dynamics model. In chapter2, structural model and the precondition in this study is stated. Translational behavior is assumed to be dominant rather than rotational behavior. In chapter3, 1x1-span flexible floor model is considered, and the dynamic properties are derived. The particular solution for rigid floor model is also dealt with as a kind of the general solutions for flexible floor model. In chapter4, 2x2-span flexible floor model is considered, and the dynamic properties are derived. In chapter5, eccentricity ratio is developed to address dynamic effect and flexibility of floor diaphragm. The range of application of the method is discussed in appendix.
 The followings are findings of this research.
 1) Modal shape of infinitely-rigid floor model is expressed by a parameter which is defined as "dynamic torsion index". It is the same as the one proposed by Ohami¹²⁾ et al. when the structure has infinitely rigid floor diaphragm. In addition, it is nearly the same as the one proposed by Fujii¹³⁾ when the structure suffers small torsion.
 2) The index is theoretically related to modal shape of 1st mode obtained by eigen value analysis. The corresponding natural circular frequency is also estimated with acceptable accuracy.
 3) Conventional static analysis, which generally considers mass-proportional lateral load, gives smaller torsion compared to 1st mode shape obtained by eigen value analysis due to so-called dynamic effect.
 4) When a floor diaphragm is quite flexible, the structure is modeled by 2DOF system and defined as perfectly-flexible floor model. Dynamic torsion index for perfectly-flexible floor model is also defined similar to the infinitely-rigid floor model.
 5) Dynamic properties of general 1x1-span flexible floor model, which is 3DOF system, is obtained by interpolation by the ones of infinitely-rigid floor model and perfectly-flexible floor model.
 6) Dynamic properties of 2x2-span flexible floor model, which is 4DOF system, is obtained by interpolation by the ones of reverse symmetric shear model(reduced 2DOF) and symmetric shear model(2DOF). It insists that the effect of flexible floor diaphragm can be separated into the ones related/non-related to torsion.
 7) The tendency of the dynamic behavior is compared to eccentricity ratio, and the key parameters to control torsional coupling is pointed out. The dynamic effect is reflected by the radius of gyration in the equivalent elastic radius.
 As a future plan, inelastic torsional behavior derived from plasticity of shear walls will be addressed.

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 Dampers have been widely used as energy-dissipating devices to retrofit existing concrete composite structures in Japan. They have also been applied in newly built concrete composite moment-resisting frames. As described above, it has been increasing demand for attaching the damper in concrete composite frames. Steel plates with shear connectors have been used to transmit stress from the damper to the concrete composite frames in the connection in the past. Some studies have attempted to clarify the shear resistance behavior of dowel action by shear connections. However, without displacement between concrete and steel plate, the shear connection does not affect the bearing resistance. Moreover, it is necessary to increase rebar in the concrete composite member near the connection, making design and construction difficult.
 In this study, the post-tensioned connection between ductile cast iron plate with shear-key and concrete was adopted. When there is no displacement between the ductile cast iron plate and concrete, frictional resistance acts; and, when displacement occurs, shear-key also acts. In this study, the shear strength evaluation of the post-tensioned connection between ductile cast iron with shear-key and concrete was investigated by the component tests and finite element analysis.
 Each specimen consisted of an RC beam and plate that simulated the post-tensioned connection. Twenty specimens were tested. Eighteen specimens were tested under cyclical shear loading, while the others were tested under cyclical shear loading and action of a vertical tensile force. The following parameters were of interest: type of plate, with or without the shear-key, the height of the shear-key, amount of the shear-key, shape of the shear-key, difference of grout materials between ductile cast iron plate and concrete, difference the post-tensioned force, and whether or not applying vertical tensile force. The vertical tensile force loading specimen was obtained by simulating a brace type damper connection. This component tests revealed two key points. First, the friction coefficient of ductile cast iron plate was the same as that of steel plate. Second, a specimen with shear-key shows higher shear strength than that without shear-key.
 Following the component tests, the strength of the proposed connection was evaluated. The strength of the specimens with shear-key was presented as the sum of friction resistance and bearing resistance by using a formula in the past. Then, finite element analysis that reproduced the component tests was carried out. The shear strength and stiffness obtained from the analysis showed good correspondence with the test results. The principal stress of concrete and mortar was confirmed. Finally, the design of the damper connection to a concrete composite structure by using the proposed connection method was shown.

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 Non-linear time history earthquake response of reinforced concrete multi-story moment resisting frame structures are calculated with a model of beam-column joints considering their restoring force characteristics which represents the interaction of moment, axial force and shear (Figure 1). The influence of the failure mechanism and strength degradation of beam-column joint are investigated by the comparison of the simulation of twenty-seven model frames (Table 1) satisfying the current seismic provisions in Japan, the model parameters for which are combination of column-to-beam strength ratio of 1.2, 1.5, and 2.0 and joint hoop reinforcement ratio of around 0.2% to 0.6% which are neglected as design parameters affecting the seismic safety in design practice in Japan. Statically cyclic response analyses of the model frames subjected to lateral load distribution pattern of Ai by displacement control at the top floor are calculated to classify the type of hysteresis loop and strength degradation (Figure 3). Then dynamic analyses of the model frames are carried out subjected to five artificial base ground motions conformed to maximum considered intensity design (MCD) spectrum and five observed strong motions (Figure 4). It is found that there is significant difference in the story drift response of the structures with different beam-column joint attributes. Particularly, in some cases, the story drift ratio increased significantly due to concentration of lateral deflection to several stories and large residual drift remains to one direction (Figure 5). It is confirmed that the differences are due to softening of stiffness and strength degradation of the beam-column joints. It is caused by the mechanism identified as joint hinging (ref. 1) which features the yielding of longitudinal reinforcement within the beam-column joint and repetition of diagonal crack open and close. The state-of-the-practice analytical model for frames does not consider the joint hinging so it significantly underestimates the story drift responses by far than seismic design criteria (Figure 8). The response of frames with beam-column joint failing in joint hinging is very sensitive to base ground motions which were synthesized with same target response spectrum. So the prediction of the response is difficult by non-linear static procedure nor non-linear time history procedure the model of which consider plastic deformation only by non-linear rotational springs at beam-ends considering hysteresis model with slip behavior. The results of incremental dynamic analysis (IDA) shown in Figure 9 reveals that the amplification less than 50% of MCD yields little difference in the response of the models whilst the amplification of 100% of MCD causes near collapse to four-story model and concentration of story drift exceeding 6% to the models failing in joint hinging mechanism, which is far beyond seismic design criteria for MCD. The current Japanese seismic design practice for beam-column joint obviously lacks the necessary reinforcing detailing provision such as minimum column-to-beam strength ratio and design of required joint hoop ratio which is much behind the seismic provisions found in current NZ3101 and ACI 318 building codes.

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 A post-tensioned precast structure is expected to reduce a structural damage by concentrating a deformation in a pressure connection between beam and column. Furthermore, the post-tensioned precast structure is also advantageous from the precast construction viewpoint, especially without grouting into a sheath. Previous test results showed that a shear strength of a beam-column joint decreased with increasing a ratio of opening to the joint volume which depends on the size and the number of sheaths to go prestressing bars through.
 To investigate the effect of the opening due to sheaths on the shear behaviors of the beam-column joints, 3-D finite element analyses were conducted on post-tensioned precast frames which are previously tested specimens. The experiments were performed on two types of specimens, plane cross-shaped joints (hereinafter referred to as the plane specimen) and space joints that additional beams were orthogonally installed (hereinafter referred to as the space specimen). These specimens were cut from a whole structure, and the common factors are the shear span of column and beam (1.415 m and 1.6 m, respectively), the cross-sectional dimensions of column and beam (350 mm × 350 mm and 250 mm × 400 mm, respectively), the bar arrangements (12-D25(SD490) + 2-D10(SD345) @90 for column, 4-D13(SD345) + 2-D10(SD345) @100 for beam, and 2-D10(KSS785) for joint), and the axial load ratio (0.13). The specimens were designed to reach shear failure at the beam-column joints before the beams fail, in accordance with design guidelines of AIJ. For this reason, the concrete strength of beams doubled (σ_B=70-85 N/mm²). The prestressing bars (SBPD for bonded specimen by grouting and SBPR for unbonded specimen by opening) having a diameter of 36 mm were inserted into the sheaths and the prestressing were introduced up to the ratio of 0.13 - 0.17 to an axial concrete capacity of the beam. The test parameters are diameters and arrangement of sheaths and the ratio of opening to the joint volume are 0 (by grouting) to 12 %. All of the specimens resulted in shear failure in the beam-column joint.
 The pressing and detaching behaviors in the connection between beam and column were modeled with an interface element having an appropriate properties. The concrete was modeled with a solid element and a Drucker–Prager criterion having 15 and 20 degrees of internal friction angle depending on the concrete strength was adopted for the compressive failure, and the linear softening behavior was assumed after maximum strength. Multidirectional crack models having a threshold value of 60 degrees were used for concretes, and the shear stiffness was reduced with increasing a crack width. All reinforcing bars were modeled with embedded elements and assumed as a bi-linear behavior. The prestressing bars were modeled with truss elements, and furthermore, for the PC bars bonded by grouting, interface elements were also used to represent a bond-slip relationship.
 The relations of the shear force and drift angle, the cracking patterns, and the behaviors of reinforcement which were obtained from the analysis were roughly consistent with the test results. The compressive damage and confining effect in the beam-column joints were numerically estimated based on the 3-D stress state. Analytical results that the shear strength of the beam-column joint decreased considerably with increasing opening ratio for the plane specimen without beams installed orthogonally. If, however, the orthogonal beams were installed, the shear strength of the beam-column joint increased by 20 % and the decrease in shear strength due to opening was softened when compared with the plane specimen because a high confining pressure was generated around the beam-column joint of the space specimen and the effect of the concrete strength was reduced.

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 Recently in Japan, the pulse type earthquakes that cause large displacement responses have been more noticeable. Some of them are predicted to become much larger than the magnitude level used in the current design, so it is promoted to set new seismic wave levels for design and to study about new design methods. To reduce damage of buildings against huge earthquakes, it has been considered to increase the elastic limit deformation using high strength steels in columns and girders. In this study, on the contrary, we propose the frames using conventional girders and hybrid H-section columns that consist of flange manufactured from high strength steel and web made with conventional strength steel. In order to apply the hybrid H-section columns to a building, the following items should be clarified; (1) method of evaluating full-plastic strength, (2) understanding the behavior of the hybrid H-section alone, (3) understanding the behavior of the hybrid H-section column in a frame. To investigate these items, we fabricated several specimens and conducted stub column tests, bending and shear tests, and cruciform tests. The experimental findings are complemented by a finite element simulation study.
 In Chapter 2, at first, we derive a full-plastic moment of hybrid H-section column under combined stress, including axial force, shear force and bending moment. Secondly we assumed the application limit of the formula. The following chapter describes that the stub-column tests and bending and shear tests were conducted to comprehend the elasto-plastic behavior caused by local buckling. Chapter 5 and 6 describes that we conducted the beam-to-column subassemblages test to verify the effects on high strength steel flange caused by axial force and plastic deformation of beam-column connection.
 By the series of experiments and analyses, we obtained the following results;

 (1) Full-plastic moment of hybrid H-section column and the application limit are shown in chapter 2.
 (2) Within the limit of application, platicizing of conventional strength steel web has little effects on high strength steel flange, therefore the hybrid H-section column can be regarded as elastic member until it reaches full-plastic strength. Further, if the width-thickness ratio satisfies the FA rank, the axial-yield of the web in an early stage has little effects on flange local buckling strength and plastic deformation capacity.
 (3) The extension of axial tensile strain, which is one of the factors of the stress degradation, can be reduced by column axial force. “Break by tensile strain” of the hybrid H-section column can be avoided unless the column axial force is neutralized by the fluctuating axial force in the case of earthquakes.
 (4) The relationship between column-to-beam strength ratio and the deformability of a cruciform frame is revealed by finite-element analyses in chapter 6.

 We proposed the design method of the hybrid H-section column that consists of flange made with high strength steels and web made with conventional strength steels. We expect the hybrid H-section column to be utilized as reasonable aseismatic column member for reducing the damage against huge earthquakes.

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  The authors 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 (PT) anchorages, and elasto-plastic damper, eliminating the residual deformation after the earthquake. In this paper, detailed and accurate analysis to simulate the system is utilized to clarify the details of local and global responses and theier relationship. The use of elasto-plastic damper requires the PT anchorages, which is found to limit performance of the rocking system. In order to explore possible enhancement, the visco-elastic damper is assumed instead, and its accurate analysis model is developed based on the damper test. The performance of the rocking system with the viscoelastic damper is analytically evaluated and the extent of improved performance is discussed.

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It is concerned that a long-duration earthquake in the future generates fatigue fractures in the steel structural components. The authors have investigated the member fracture of axial members including cold-formed circular hollow sections. According to previous study of steel braced frames, it’s suggested that more ductile structural components should be applied to a steel structure achieving higher seismic performance. On the other hand, it is needed to develop an aseismic design method of a steel braced frame taking member fracture into account of frequent middle or large earthquakes. In this paper, the interaction of cumulative deformation capacity between a circular hollow section brace with different diameter thickness ratio and a steel frame is investigated for extending basic knowledge of ultimate seismic resistance of steel braced frame, using finite element analysis, experiments including shaking table testing and evaluation of ductility factor.

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 This paper deals with beam-end details of non-scallop method for field welding. The welding position of the lower flange in field welding is downward, the scallop construction method is generally used as the non-scallop construction method is difficult. The stress concentration occurs at the bottom of scallop, therefore brittle fracture of the beam end flange from the bottom of scallop is frequently reported. For that reason, joint types for preventing premature fracture from the bottom of scallop have been proposed. For example, those are horizontal haunch method, perforated flange method, etc. However, these joint types show sufficient deforming capacity, but in many cases volume of steel and processing cost increase.
 The purpose of this study is to propose welding non-scallop construction method filling the holes of scallops in field welding in order to eliminate stress concentration at bottom of scallop by changing the shapes of scallop parts. In this paper, filling welding construction method and inserting fillet construction method are used. It is clarified beam end details that improve deformation capacity of field welding beam-to-column joint with pre-built-up H-shaped beam. Full scale tests were carried out. The results obtained here are shown below.

 1) Method to fill a column and the gap of beam-web by using welded joint (BM_L_W specimen, shown in Fig. 1c-3)) and to weld fillet weld diaphragm and billet (BS_P65 specimen, shown in Fig. 1b-2)) were most suitable as beam-end details improved deformation capacity of beam-to-column connections with field welding.
 2) Cumulative plastic deformation ratio (shown it as follows with ηs) of BM_L_W specimen was 8.2, and the value of ηs exceeded deformation capacity of shop welding non-scallop method (shown in Fig. 13). Also, rate of increase in strength (shown it as follow with α) of BM_L_W specimen was 1.48. When it consider the restriction effect by diaphragm, strength of beam-end flange fracture reached tensile strength of base metal. From this, the stress concentration in a scallop bottom disappeared, and fracture origin shifted to end-tab.
 3) ηs of BS_P65 specimen was 6.4, and at the same level as deformation capacity of shop welding non-scallop method (shown in Fig. 13). A of BS_P65 specimen was 1.40. As well as BM_L_W specimen, strength of beam-end flange fracture to the same level as base material toughness.
 4) Deformation capacity of beam-end details which stress concentration remained behind in scallop bottom (BS_P50, BM_F and BM_L specimens) decreased in comparison with its BS specimen (shown in Fig. 13).

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 In the 2008 Iwate-Miyagi Nairiku Earthquake occurred at volcanic area, large amplitude strong ground motions were recorded at observatories near fault region. Because subsurface structure is very complicated in the volcanic area, it is pointed out that considering heterogeneous attenuation structure is important to investigate characteristics of earthquake ground motions. In this study, we conducted tomographic analysis using seismic intensity data of aftershock records for the purpose of estimating heterogeneous attenuation structure. We also tried to reproduce seismic intensity of aftershocks which occurred near and on the asperity of the main shock. By comparing estimated and observed seismic intensity, we indicated how the heterogeneous attenuation structure influenced amplitudes of earthquake ground motions.
 The tomographic analysis using seismic intensity was conducted in three phases of procedures. First, we obtained an attenuation relationship of seismic intensity using strong motion records of inter-plate and intra-plate earthquakes, and evaluated a site factor of each station. Next, we obtained the attenuation relationship for crustal earthquakes using records of aftershocks assuming the same site factor. We then calculated residuals of each observed and estimated seismic intensity data. Finally, supposing residuals to be attributed to the heterogeneous attenuation structure, a block inversion was conducted dividing the focal area of the main shock to strip form with horizontal sizes of approximately 3km. An attenuation level of each block was expressed as increase/decrease ratio of seismic intensity (we called “G” value). In this block inversion weighting by the ray length which passes through the block, 326 records of Aratozawa Dam, Kurikoma Dam and KiK-net stations IWTH25, IWTH26, MYGH02, IWTH28 and AKTH04 which located near and on the fault plane of main shock were used.
 To confirm a resolution of G value estimated at each block, we conducted a numerical experiment using checkerboard. Although large errors were found where the number of ray was sparse, errors were less than 10% in most domains on the fault plane of the main shock. We conducted the same inversion using observed records, and found that estimated heterogeneous attenuation structure was very complicated. As indicated in the previous studies, high attenuation zone was distributed around Mt. Kurikoma. Around IWTH25 which located just above side of the main shock hypocenter, low attenuation zone was distributed. Around Aratozawa Dam and Kurikoma Dam, attenuation structure was very complicated too.
 We tried to reproduce seismic intensity at IWTH25, Aratozawa Dam and Kurikoma Dam for 3 aftershocks which occurred near and on the asperity of the main shock. When uniform attenuation structure was used, the observed seismic intensity of IWTH25 and Aratozawa Dam were larger than estimated. Observed seismic intensities at Kurikoma Dam were slightly smaller than estimated. In the case of considering heterogeneous attenuation, reproducibility of observed records was greatly improved. In case that azimuths of hypocenters are different, amplitudes of the earthquake ground motions are different even if magnitude and hypocentral distance are the same. We concluded that the propagation path greatly influences amplitudes of earthquake ground motions. It is thought that this complicated attenuation structure was one of factors that large amplitude strong ground motions were recorded at particularly IWTH25 and Aratozawa Dam in the main shock.

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