Natural period and damping factor are important values in seismic design because of their impact on the response of superstructures when their behavior during an earthquake is estimated. However, commonplace earthquake observation records contain various effects, as respresented by the soil–structure interaction. This study focuses on the records of large shaking table tests and investigates the vibration characteristics and time shift for reinforced concrete (hereinafter RC) specimens subjected to more than one large amplitude seismic motion. The experimental data are analyzed using the autoregressive exogenous (ARX) model. Moreover, the effects of the maximum deformation caused by the large seismic motion on the vibration characteristics are investigated.
 The main results obtained are as follows:
 1) The first damping factors for the three different types of RC specimens with first natural periods of approximately 0.2, 0.4, and 0.5 s were approximately 8~10, 4~8, and 1~2%, respectively. The result showed a slight variability in these values. Meanwhile, the second natural damping factor only had a little variability in the specimens with first damping factors of approximately 3, 2, and 1%, respectively.
 2) The first and second natural periods and damping factors tended to progressively increase even when the RC specimens were seismically loaded at levels from a nearly linear response to a slightly nonlinear response, except for the first ones of specimens 1 and 2. This finding was thought to be the reason why the minimal injury of specimens cumulatively increased.
 3) The natural period had an amplitude dependency that underwent a gradual transition from left to upper right on the logarithmic axis of the drift angle according to the resulting maximum deformation, which was the same as that in previous studies²⁰⁾. Moreover, the natural period increasingly became longer and subsequently kept the condition every time the specimens were seismically loaded in amplitudes larger than the previous value. A trend toward increase in amplitude dependency according to the maximum deformation was found.
 4) The more the natural period tended to increase, the more the maximum deformation that the specimens increased. The rigidity lowering rate or ratio of the natural period showed gradual changes according to the resulting maximum deformation, regardless of the specimen sizes and structural form. The trends roughly agreed with the characteristics of the skeleton curves typically modeled as an RC structure element.
 5) The damping factor showed a tendency for increased values when the specimens obtained a non-linear domain once even when experiencing comparatively small amplitude seismic motions. This finding was thought to be the reason why the effect of hysteresis damping was relatively larger than those associated with plasticized specimens.
 6) In specimen 3, the more the ratio of the natural period increases, the more the damping factor linearly increased. In other words, the relation of the natural period and the damping factor had a positive correlation. The damping factor also had a trend for increased values, such as that of the natural period when the maximum deformation that the specimens experience increased. Meanwhile, the change ratio of the damping factor was approximately constant along the logarithmic axis of the drift angle.

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 We estimate the broadband source model of the 2016 Kumamoto earthquake (M_J7.3, Mw7.1) based on the empirical Green's function method in order to improve strong motion predictions of crustal earthquakes. Firstly we estimate fmax of 37 earthquakes with M_J4.0 to 7.3 occurring in the source region of the main shock using source spectra estimated by the spectral inversion analysis in our previous paper. The estimated fmax of the main shock is 4.4 Hz, which is smaller than 6 Hz for the strike-slip earthquakes with almost the same magnitude. The fmax tends to increase in accordance with the magnitude decreases. The differences of the fmax between the main shock and Mw5-class two element earthquakes are corrected. The nonlinear amplification factors of strong motions during the main shock are also corrected using horizontal-to-vertical spectral ratios between strong motions and weak motions at K-NET stations. After these corrections we estimate the broadband source model of the main shock using K-NET and KiK-net (borehole) strong motion records at 18 stations.
 We study three cases of outer faults as regions searching strong motion generation areas (SMGAs). In the first case (A-model), two northwest-dipping faults around the Futagawa fault and the Hinagu fault are assumed. In the other cases (Y-model and K-model) only the northeastern part of the Futagawa fault near Mt. Aso is changed to be a southeast-dipping fault based on crustal deformation data and some newly developed source models. Since few aftershocks were occurred there, we assume Y-model and K-model with different strike and dip angles. After estimating the broadband source model for A-model by the forward modeling, the broadband source models for Y-model and K-model are estimated by the grid search method using evaluation functions for envelopes of acceleration and waveforms of velocity filtered in the period range of 0.1 to 5 s.
 The Y-model is the best and the A-model is the second best although the difference of the evaluation-function-value of both models is small. The plane positions of the SMGAs on the fault near Mt. Aso are the almost the same between Y-model and A-model and is in the so-called Aso gap where few aftershocks were occurred. The SMGAs for both models extend to the inside of northwestern region of the Aso caldera. For the Y-model the short-period spectral level is almost the average for crustal earthquakes by Dan et al. (2001) and the total area of SMGAs are 1.16 times of the average for the total area of asperities for crustal earthquakes by Somerville et al. (1999). The 11.5 MPa of stress drop of five SMGAs is almost the average for crustal earthquakes. The source parameters of A-model are also almost same to previous relations for crustal earthquakes. The results on scaling relations are consistent with Irikura et al. (2017) in general but the existence of SMGAs inside Aso caldera is different from Irikura et al. (2017). The rupture velocity of 2.8 km/s for SMGAs on the Futagawa fault is faster than 2.4 km/s for the SMGA on the Hinagu fault. The positions of SMGAs located in the northeast side on the northwest-dipping Futagawa fault agree better to high peak moment rate areas than large slip areas estimated by Yoshida et al. (2017). This result suggests that short-period ground motions generate slightly deeper areas than long-period ground motions. It is qualitatively found that strong motions with large velocity pulses observed at KMMH16 (Mashiki) in borehole are generated by the SMGA located in shallow depth just beneath KMMH16.

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 In Japan, recently some research projects on CLT (Cross Laminated Timber) construction are conducted to establish the law on the design method of CLT buildings suited with the Japanese regulations of seismic design. However, at the present moment, building with CLT construction have to be structurally designed only under “Approval route” where seismic performance of objective building is verified through the time history response analysis to obtain the approval by the minister of MLIT (Ministry of Land, Infrastructure, Transport and Tourism), since the law concerned with practical structural design of CLT construction is not yet issued in Japan.
 As part of the project in February 2015, to discuss the seismic performance to investigate the structural design method of building structures of CLT, and gave a vibration table tests in order to obtain the basic data. Compressive rupture at the corner of CLT wall panels occurred in shaking table test

 Indication of the construction of the analysis model, tracking behavior when exceeding the test results, as aid in the proposed formula, the construction of the analysis model is useful. In this paper, we report the construction method and accuracy verification of the analysis model, and subject of the analysis model is 1.5 story of plane specimen.

 In this study, directed to a structure that uses the CLT panel 1.0 to 2.0 meters wide in the wall, and use the tensile bolt and screw hitting hardware is at the junction
 Using the FEM shell model for the construction of the structural model. It reason for using FEM shell model is capable of confirmation of the distribution of compressive stress in the shaking table in the cause in which the considered panel plane of the crushing of the panel leg seen in destructive nature of the test, also, the contact surfaces of the joint and the panels to each other by making substitutions are arranged on the spring element, because we consider an element comparison of the test results and the analysis results can be achieved.

 In this model, CLT panel is an elastic shell elements, the junction is a non-linear spring element. Structural performance of CLT panels and joints were set based on the history of the experimental results. Based on the elements test results, set the properties of each element, you create a structure model of the 1.5-story plane test by the FEM shell model. To compare the analysis and test results of the structural model, we performed the accuracy verification of the structural model, to confirm the validity.

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 Many ceiling collapse damages were observed in wide-area structures such as gymnasiums during the 2011 Great East-Japan Earthquake and the 2016 Kumamoto Earthquake. The prevention of ceiling collapse phenomena is an important issue not only to save people's lives, but to keep these facilities to be safely used as shelters after earthquakes.
 In this paper, a numerical analysis to simulate the ceiling collapse in a full-scale gymnasium specimen, which was tested at the E-Defense shaking table facility in 2014, was conducted. A numerical model consisted of steel structural frames and suspended ceilings were constructed. All the members were modeled using linear Timoshenko beam elements and the adaptively shifted integration (ASI) - Gauss code was applied. Hangers and hanging bolts were modeled in one piece. The plaster boards were assumed as rigid in out of plane direction and only the mass of rock wool boards was considered. Their strength were neglected. Clips and screws were modeled with minute, small elements. Each plaster board was modeled separately to consider local contact between plaster boards, which was simulated by modeling the screws slightly apart. Elasto-plastic buckling of braces and hanging bolts were considered by modeling them with eight beam elements each and two hinge elements on both ends. The clips connecting ceiling joists and ceiling joist receivers are small and delicate components that may be detached during repeated excitation. Once there is a local detachment of clips, a change in the load distribution may cause a chain reaction of detachments, which ends in a drop of plaster boards. Furthermore, the detachments of hanging bolts that are connected to the structural members composing the roof, and failure of screws on plaster boards are assumed to be other main causes of the ceiling collapse. The results of some preliminary tests conducted to see the actual strength of these components are implemented in the analysis for criteria.
 The numerical result was validated by the experimental result, which was performed at the E-Defense under an input of two continuous K-NET Sendai 50% waves. The acceleration responses, the spectrum and the displacement responses obtained on the roof matched well with the experimental result. According to the results, the plaster boards near walls pattered down occasionally at the first peak of the first wave. These were due to detachment of clips and screws caused by collisions to the walls. Then, the clips near roof top began to get loose due to buckling of hanging bolts caused by vertical excitation, which ends, at the first peak of the second wave, in drop of plaster boards in a wide range. The numerical result had shown the collapse of the ceilings progressed owing to the detachment of clips that connected the ceiling joists to the ceiling joist receivers, which eventually led to a large-scale collapse of the ceilings.

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 Expansion-type steel pipes are used for rock bolts in tunnel excavation work in Europe. The authors are trying to apply the expansion-type steel pipe for the components of the reinforcement soil under small building foundations. The diameter of the steel pipe for rock bolts is expanded from 36 mm to 54 mm by adding inner high water pressure. The authors have carried out the field tests to confirm the reinforcement effect of the expansion-type steel pipe piles.
 From the compression tests of a piece of the steel pipe before the field tests, it was obtained that the average proportional limit load of the raw pipe pieces was 96.3 kN (stress intensity 316.7N/mm2), and that of the expanded steel pipes was 104.6 kN (stress intensity 344.1N/mm²), and then the strength of the expansion-type steel pipe piles were increased by about 9% by through hardening work.
 These test results were summarized as follows,
 1) In order to examine the soil conditions around the expansion-type piles, piles were placed at three different intervals (300 mm, 450 mm, 600 mm) between the piles, and then SWS tests were carried out before and after expanding the piles at the middle position of each piles. The compaction effect on the surrounding soil of the expanded piles decreased as the pile spacing increased. In relatively loose sand, the compacted area is up to about 8 times (450mm) of the pile diameter.
 2) From the results of the competitive axial tensile load field tests (using the expansion-type steel pipes and normal steel pipes with the same expanded diameter) in three sites (Toyonaka, Fukutsu, and Karatsu), the ultimate frictional resistance of the expansion-type piles was found to be about three times higher than that of the normal steel pipe pile.
 3) According to the results of ten field tests on the expansion-type piles in the same above mentioned sites, the following equations were obtained for the relationships between the ultimate friction τ_s and the average N value from the SPT test, or the average N' value from the SWS tests using Inada’s conversion formula. However, these equations are be based on a small amount of data and a relatively large standard deviation (σ = 2.2N, or σ = 1.7N').
 τ_s=9.9 N (kN/m²)
 τ_s=15.9 N' (kN/m²)
 4) It is supposed that the increment of the normal soil stress acting on an expansion-type pile in sandy soil increases the ultimate frictional resistance of the pile. On the basis of this supposition, the comparisons between the solutions of the ultimate friction based on the cavity expansion theory and the test results were in good agreement.

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 In seismic design of pile foundation by static stress analysis, a model in which a pile is a beam and the beam and the ground are connected by multiple springs (coefficient of subgrade reaction k_h) is used as a practical design. The stress and horizontal displacement of the piles obtained from this method strongly depends on the evaluation accuracy of the coefficient of subgrade reaction k_h as well as the specification section of the pile body. In this study, we propose a method to evaluate coefficient of subgrade reaction k_h based on shear wave velocity. We also propose a method to evaluate k_h from the inverse analyses based on the Chang's formula using the results of past horizontal loading test data of single piles with rotatable pile head condition including large diameter piles performed at in situ. The following conclusions are obtained.

 (1) The deformation modulus E_b obtained from the pressuremeter test can be suppressed its variation by considering the strain dependency of the ground rigidity. E_b' is about 1/18 in sandy and cohesive soils, compared with E₀ obtained from shear wave velocity.

 (2) In the case where the reference displacement is set to 1 cm for the displacement at pile head, the relationship between the coefficient of subgrade reaction and the pile head displacement with small variation can be obtained in the case where the pile diameter dependence is set to (B/B₀)^-1/2 and the nonlinearity due to the displacement at pile head is set to (y/y₀)^-0.6. On the other hand, when the reference displacement is set to 3% of the displacement at pile head / pile diameter, in the case where the pile diameter dependence is set to (B/B₀)^-1 and the nonlinearity due to the displacement at pile head is set to {(y/B)/(y/B)₀}^-0.6, small variation of relationship between coefficient of subgrade reaction and displacement at pile head / pile diameter is obtained. However, superiority and inferiority of both can not be judged only from analysis of horizontal load test data.

 (3) A calculation method of the coefficient of subgrade reaction using shear wave velocity for evaluate horizontal resistance of piles by the Chang's formula is proposed. Comparing with the actual measured values under rotatable pile head condition, the simulation analysis values by the proposed method and the Chang's method show that the pile head displacement is slightly larger, the maximum bending moment is slightly smaller and the maximum bending moment generation depth is shallower.

 (4) Although the subjects are for only the rotatable pile head condition and the above tendency is observed. But the Chang's formula is useful for evaluate the horizontal resistance of the elastic pile considering the nonlinear behavior of the ground if the ground near the ground surface can be regarded as almost uniform and the influence of the ground deformation is small.

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 1. Introduction
 This paper describes shaking table tests of an RC building. The shaking table tests were conducted in E-Defense, through a special project to quantify collapse margin of buildings that are commonly seen in urban areas in Japan.
 2. Outline of the Shaking Test
 The test specimen was a 30% scale model of a 6-story RC building designed according to the current Building Standard Law in Japan. The test specimen consisted of two moment-resisting frames in the longitudinal direction, and four frames with multi-story shear walls in the transverse direction. The two interior frames had shear walls and the others had nonstructural walls with openings from the second to the sixth stories.
 3. Outline of the Test Results
 At the shakings in the tests, shear failure of walls at the first and second stories occurred, flexural hinges were formed at both top and bottom of the columns at the first story, and the building specimen collapsed finally with collision between balconies of its third and fourth stories and steel frame for safety.
 4. Details of the Test Results and Collapse Process
 Rigid floor assumption didn't seem to be satisfied because shear deformation angle of slab between X1 and X2 frames became larger after the maximum shear capacity observed as shown in Figure 11.
 5. Relation of Input Wave and Collapse
 After the maximum response shear capacity, by the same input motion, the response of the second input increased than that of the first input as shown in Figure 13. It was indicated that, the response by the same earthquake at least twice should be considered to evaluate collapse margin.
 6. Conclusion
 Shaking table tests of 30% scale 6 story RC building were conducted. The findings of this study are as follows:
 1) 1st and 2nd story walls were failed in shear manner, especially shear sliding failure was dominant. And load carrying capacities of 1st and 2nd story seemed to be observed during the tests.
 2) In the columns at 1st story, top and bottom hinges were formed, and these columns kept their capacities to carry vertical load through the tests, because of their high ductility. Though flexural failure at the member end of 2nd floor girder occurred with buckling of main bars, shear failure didn't occur.
 3) X2 frame, which consisted of continuous walls from 2nd to 6th stories with 2 columns at 1st story, had lower stiffness at the 1st story. The shear deformation angle of slab between X1 and X2 frame increased after the maximum response, case #3-5. It was indicated that the floor couldn't keep rigid floor assumption through the shaking tests.
 4) Non-structural walls damaged finally.
 5) The response by the same earthquake at least twice should be considered to evaluate collapse margin. In this study, maximum velocity of input motion was used for the earthquake index. How to define the “same earthquake” or indices of earthquakes should be discussed in further researches.

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 In regions prone to earthquake-induced ground shaking, buildings with insufficient seismic capacity may suffer severe damage and in the worst case collapse. Collapse of buildings lead to loss of many human lives. Thus, collapse prevention of the buildings is the first priority in realizing earthquake-resilient community in such regions. This study proposes the concept of a base shear capped building for collapse prevention as one of promising seismic retrofits. The structural system detaches the superstructure from the foundation in order to prevent collapse by letting the superstructure slide under huge earthquakes. When small earthquakes occur, the proposed structure does not slide against the foundation and behave like a fixed-base structure. When huge earthquakes occur, the structure starts to slide because the horizontal force which develops between the sliding base and foundation exceeds the maximum static friction force.
 The friction coefficient is one of key parameters in the sliding system. In this paper, graphite lubricant is used between steel and mortar, materials commonly used in building construction in order to obtain a target friction coefficient, 0.2.
 Previous numerical studies with a SDOF system revealed that the mass ratio, the weight of the superstructure over the total weight, was one of the ruling parameters. The objectives of this study are as follows: (1) Shaking table tests were conducted to evaluate the basic sliding behavior; and (2) The maximum base shear coefficient was estimated by numerical simulation when the proposed structure is subjected by pulse-type ground motions.
 In the experimental part, two types of specimens were designed: a basic specimen that simulates a SDOF system having a sliding system and a frame specimen that consisted of beams and columns. With those specimens, the stability of friction coefficient and the effects of the mass ratio and the variation of axial forces on the sliding behavior were investigated.
 Based on the test results, a simplified SDOF model featured with sliding behavior is developed, and the maximum base shear is estimated under pulse-type ground motions. Two types of input motions are used: an impulse motion and a set of SAC20 ground motions. Even if an existing building is brittle, it has some post-yielding ductility before collapse. To reflect this, additional numerical simulation is conducted using inelastic models and estimate the maximum required base shear coefficient when slight ductility, say two in ductility ratio, is permitted.
 The major findings are as follows: (1) Experimental studies verified the stability of friction coefficient between steel and mortar lubricated with graphite powder throughout all loading cases, and the dynamic friction coefficient is 0.16. (2) Even when the variation of axial force reached 50%, four column bases displaced equally, indicating that the effect of axial force variation on sliding behavior was minimal. (3) Numerical studies verified that there is an upper limit of the maximum base shear coefficient when the model is subjected to impulse motion, and the value of the upper limit is twice the friction coefficient. (4) For SAC20 ground motions, no obvious upper limit was present. However, even for earthquakes in level 2 (10 percent exceedance for 50 years), the maximum base shear coefficient remains at most 2.5 times the friction coefficient. (5) If slight ductility is permitted, the required maximum base shear coefficient can be reduced about twice the friction coefficient.

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 The bearing walls of steel-framed houses are composed of thin-thick steel frames, sheets such as plywood and drilling screws for fasteners. The sheet to frame joints fastened by drilling screws bring up the complicated behavior of bearing walls, Therefore, structural properties of the bearing walls have to be estimated by full-scale experiments to design steel-framed houses. In order to estimate those properties without experiments, it is needed to make clear sufficiently about the bearing mechanism of walls.
 In this paper, on the basis of studies on full-scale experiments by authors, it will be discussed the simple method which can be easily estimated the characteristics of load-deflection relationship on steel-framed bearing walls. Furthermore, the effectiveness of the proposed method is discussed by comparisons of experiments.
 On the bearing walls subjected to horizontal load H, the displacement u is given by the sum of three components (Fig. 2). These are displacement u_b caused by bending, displacement u_s by the shearing of sheet and displacement u_n caused by slip-displacement of sheet to frame joints. The experimental study¹⁴⁾ showed that the displacement u_n govern the elasto-plastic behavior of whole bearing walls. Then, it becomes important to estimate the displacement u_n for the bearing walls subjected to horizontal load H.
 The curve of H-u_n relationship can be calculated by Eq.(3)-Eq.(6) using numerical calculation of Fig. 6. Eq.(3) is derived geometrical relations with the sheet and framing members in Fig. 4. Eq.(6) are derived from the equations of equilibrium for the fastener forces acting at each framing members (Fig. 5). The example of the numerical calculation (Fig. 7) is indicated that the figure of H-u_n curve is similar to that of f-δ curve of drilling screw joints, which is idealized to multi-linear type.
 The repeated calculations are not practical for design of the steel-framed bearing walls. To achieve the simple method, f-δ curves and the H-u_n curves are modeled into multi-linear type in Fig. 8. For the tangent stiffness K_n,i and the load H_pi at tangent stiffness changing point of H-u_n curve idealized to multi-linear type, the simple estimation equations are discussed, and Eq.(13) and Eq.(21) are proposed. Just for information, H-u relationship is the sum amount of H-u_b relationship, H-u_s relationship estimated by elastic theory and H-u_n relationship by proposed method.
 The calculation results by the proposed methods are compared with the experiments on steel-framed bearing walls¹⁴⁾ in Fig. 14 and Fig. 15. The parameters of specimens are shown Table 1. The results by the proposed methods are agree with that of experiments except Specimen A-100, B-100 and C-100 of which maximum strength are given by buckling of plywood. And also, for the initial stiffness, yielding load and maximum load, the calculation values are good agreement to the results of experiments.

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 It is well know that initial imperfections (e.g. bow-shaped imperfection of member, bow-shaped imperfection of plate and residual stress) have an influence on the performance of the columns. Most studies regarding this issue are investigated under single axial load or single shear force. In reality, the columns of steel structures are subjected to axial load and bending moment. Therefore, it is necessary to clarify the influence of the initial imperfections under combined loading. The influences of initial imperfections on the performance of square steel tubular columns under compressive axial force with one end monotonic bending moment were investigated by means of FEM in our previous study. As mentioned before, the columns of steel structures are subjected to axial load and bending moment, and the moment diagram is antisymmetric bending moment distribution or bending moment distribution close to antisymmetric. Therefore, it is not enough to clarify one end bending moment distribution. Also, in the previous study, the influence of the residual stress in the circumferential direction was not considered despite it exists in the member. In this study, the influences of initial imperfection on the performance of the square steel tubular column which is subjected to a compressive axial force with monotonic antisymmetric bending moment are investigated. The bow-shaped imperfection of the member (global imperfection) and continuous bow-shaped of the plate (local imperfection) are selected as geometrical initial imperfections and these imperfections are described by trigonometric function to reproduce easily. The residual stress in the longitudinal direction and the residual stress in the circumferential direction are selected as material initial imperfections. Firstly, the influence of initial imperfection on the performance and on the elastic-plastic behavor is investigated individually. Secondly, the influence of combined initial imperfections on the performance of the columns and on the elasto-plastic behavor is investigated; comparison between the experimental results are shown.
 Firstly, followings were found from the analysis results where initial imperfection is introduced in the member individually.
 1) When the ultimate state was determined by local buckling, the global initial imperfection had a small impact on the performance. When the ultimate state was determined by bending deformation in in-plane, the direction of global imperfection had an impact on the performance as well its amplitude.
 2) The amplitude of the local imperfection had a great impact on the performance of the columns. The maximum bending moment and the deformation capacity significantly decreased when its maximum amplitude exceeded 10% of permissible deviation.
 3) When the ultimate state was determined by bending deformation, the plastic deformation capacity decreased with the increase of the amplitude of the residual stress in the longitudinal direction; initial stiffiness gradually decreased with the increace of its magnitude.
 4) Regardless of the ultimate states, with the increase of the amplitude of the residual stress in the circumferential direction, the maximum bending moment and plastic deformation capacity decreased. Secondly, followings were found from the analysis results, where combined initial imperfections are introduced in the member.
 5) In comparison with analysis results which were introduced the initial imperfection individually, the influence of the combination of initial imperfections on the variation trend of the performance was not confirmed. The local imperfection had the most significant influence on the perfomance in the imperfections that are considered in this study.
 6) Validation of the numerical simulation was also performed; initial imperfections that could simulate test results in reasonable accuracy was shown.

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 When steel moment frames are subjected to seismic forces, H-shaped beams carry the gradient flexural moment. Large cross-section beams are used as main beams to design structural members effectively in real large space structures. Long span beams may not possess the plastic strength due to lateral buckling, so that many lateral braces along the beams should be set up to prevent the lateral bucking deformation (AIJ 1998). Most oy beams in frames are connected by continuous braces such as folded-roof plates, which are effective to prevent the lateral buckling oy beams. However, in the Japanese design code, non-structural members are not considered as the braces.
 On the other hands, there have been many moment resisting frames with dampers to prevent damages oy main frames recently, and then H-shaped beams connected with dampers are subjected to compressive axial forces in addition to gradient flexural moment. If the beam carries the large axial force induced by the damper during earthquake, the lateral-torsional buckling behavior oy H-shaped beam becomes more unstable than that under flexural moment only. The axial force which the beams carry is possible to exceed 30% oy yield load oy the beam.
 Therefore, in this paper, the lateral buckling behavior for H-shaped beams with continuous braces under gradient flexural moment and compressive axial force is clarified and elasto-plastic lateral buckling stress oy the beams or lateral stiffing force and rotational stiffing moment oy continuous braces are evaluated by the energy method and numerical analyses.
 In this study, for H-shaped beams with continuous braces subjected to gradient flexural moment and compressive axial force, two types oy loading conditions and two types oy bracing rigidities are considered. One oy the loading conditions, which is called as Type A, is the case that the upper flange's compressive load is larger than the lower flange's one in the left side oy beam as shown in Fig. 3(a), and another, which is called as Type B, is that the upper flange's compressive load is smaller than the lower flange's one in the left side oy beam as shown in Fig. 3(b). Furthermore, the ratio oy the compressive axial force, P₂ to P₁ is represented as an axial force ratio ‘p’ in equation oy elastic lateral buckling load. The continuous braces are divided into the lateral braces, k_u, and rotational braces, k_β, as shown in Fig. 1. In the case oy TypeA, k_u is effective for preventing lateral deformation oy compressive upper flange, whereas in the case oy TypeB, k_β, is effective for preventing torsional deformation.
 This study is conducted by the following procedures:
 1. The equations oy lateral buckling loads oy H-shaped beams with continuous braces under gradient flexural moment and compressive axial force are derived by energy method. To simplify the equations by energy method, the new equations oy lateral buckling loads are suggested with reference to the terms oy the flexural and torsional rigidities oy beams, the rigidities oy braces, and condition oy the loads.
 2. The elasto-plastic buckling behaviors oy the beams are simulated by elasto-plastic large deformation analysis. The lower bound oy the elasto-plastic buckling stress oy the beams can be evaluated with the interpolated buckling curve between those oy bending member and compression member, which are provided by Recommendation for Limit State Design oy Steel Structure (AIJ), depending on the axial force ratio.
 3. The upper bound oy moment and lateral force which continuous braces carry at the lateral buckling oy beams is evaluated based on the ratio oy the flexural and torsional rigidities oy beams, the rigidities oy braces, the axial force ratio, and the gradient oy flexural moment.

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 Existing wall-type precast reinforced concrete residential buildings maintain high structural quality, although they were constructed widely in Japan more than 40 years ago. A large number of the residential units in these existing buildings are standardized and typically small. Consequently, they do not suit for modern living uses. In order to utilize these buildings, seismic behavior was evaluated by static pushover analyses in past research. It was concluded that the failure mechanisms are rocking of the walls in the transverse direction and beam yielding in the longitudinal direction. In this research behavior of the foundations was not studied.

 Past large earthquakes such as Hyogoken-Nambu earthquake in 1995 showed that the WPC buildings maintained high structural seismic resisting performance and the foundations including piles were relatively weak. This fact implies need of analytical study of the seismic behavior of the buildings considering their foundation and soil. It is more true on the evaluation of their performance in the transverse direction, where the behavior of the foundation is more influential to the overall structural behavior than the longitudinal direction.

 In this research, time-history seismic response analyses of the WPC buildings under large earthquakes with 500 year of the recurrence period are conducted. Two cases of combinations of the soil condition and foundation system are studied. One is continuous footing on hard soil and the other is pile in soft soil. 2-D sway-rocking models were created for the two cases with corresponding sway and rocking soil springs. The superstructure is the model which is identical in the cases and composed of inelastic joint springs and elastic precast concrete panels. Pile stresses are evaluated by applying the seismic deformation method. Findings in this research are shown below:

 (1) In the study case for the building with the continuous foundation, uplift of the building by the overturning moment (OTM) is observed. It is referred that the failure mechanism is rocking of shear walls associated with failure of the vertical joints in past study of pushover analyses with the fixed-base model. In the time-history analyses, the maximum base shear coefficient (C_Q1MAX), which is defined as the ratio of lateral force to the building weight, is 0.73.

 (2) In the study case with the pile foundation, the piles can fail in shear before the collapse of the superstructure. While CQ1MAX reaches 0.81 with the elastic pile model, it would be lower in studies considering inelastic shear failure of piles.

 (3) In the study case for the building with the continuous foundation, shear stress of shear walls is no more than 1.8N/mm², which is lower than probable ultimate shear stress (2.0-2.7N/mm²). Although, in the study case with pile foundation, the shear stress is at most 2.1N/mm², this is the lower limit of ultimate shear stress and would decrease considering shear failure of piles. Therefore, shear walls would not fail under the large earthquakes, while foundation may be damaged. This analytical finding agrees with the past seismic damage of this type of buildings.

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 Most of the loss suffered in the Great East Japan Earthquake was due to the tsunami rather than to the earthquake itself. An unusual aspect of these disasters was that much of the structural wreckage that was swept up by the tsunami remained and drifted on the sea. Some of the wreckage caused subsequent damage to coastal structures. These drifting objects caused by the tsunami included containers, boats and ships, cars, caissons, and other objects from the harbors. Thus, it is necessary to solve these problems in order to plan the safe coastal zone. However, there is no effective method in order to verify this subject, and few reports are available on characteristics of collision behavior of huge ship in tsunami.
 These problems can be resolved by the hydraulic model experiment. However, it is difficult to verify the scale model experiment, in addition these need enormous cost. On the other hand, numerical simulation method is suitable for analyze the collision phenomena of huge ship in tsunami. The MPS method is a particle based method originally proposed by Koshizuka et al. and is a Lagrangian procedure for simulating a flow field employing the moment-to-moment motions of particles distributed in a space. The most distinctive aspect of particle methods is that they do not require consideration of connections between calculation points. Because of this, the MPS method is well suited for analysis of strongly non-linear phenomena accompanying large deformations of free surfaces.
 The objective in this paper is following items, 1) to propose and evaluate the friction elastic body model for collision phenomena using MPS method, 2) to clarify characteristics of collision behavior of huge ship.
 The present numerical model of the MPS method is applied the dynamic analysis of elastic solids developed by Koshizuka et al. And, the authors approach the new method of the MPS which can analisys friction phenomena between solid in this research.
 As these results, the authors found that present model is suitable for calculation of collision phenomena through the verifications of the wave tank experiment and the analytical solution. In addition, the authors confirmed basic characteristics of behavior of collision phenomena of huge ship in tsunamis. Further, it was concluded that, the impulse due to collision force without friction force on the surface of the huge ship is 55% larger than the impulse of only tsunami waves in case of reflection tsunami flow from the land structure is small.

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 Various optimization problems have been studied for the purpose of structural morphogenesis by many researchers. Structural optimization problems can be classified into three different sub-problems, namely size, shape and topology optimization problem. Size optimization problem is consisted of small sets of design variables. The shape and topology of a structure are defined by a set of design variables, and these design variables are adjusted to achieve given objectives, such as minimum volume. Such optimization problems can be solved iteratively, using gradient-based techniques. Introducing more design variables increases the complexity of the optimization problem. Therefore, it becomes difficult to solve the optimization problem by using MP techniques with large sets of design variables. Heuristics can be improved the difficulty. There are many studies using heuristics like genetic algorithm and simulated annealing.
 An effective method for structural morphogenesis inspired by self-organization phenomena is presented in this paper. Self-organization is a phenomenon that an entire structure gradually emerges by interaction between elements of the structure, and the elements are affected by the entire structure. Since the self-organization algorithm consists of simple calculation iteration, it can be applied to problems with large number of design variables. Proposed method is applied to problems of uniform member length, minimization of strain energy and cross-section design for frame structures, and the effectiveness is demonstrated through some examples.
 On the other hand, the number of projects incorporating computational design has increased in recent year, and designs with complicated forms composed of free surfaces are also increasing. In order to design such a shape, the designer needs to consider the rationality of the structure from the initial stage. So, it seems necessary to develop simple software for the structural morphogenesis. Therefore, we developed components of Grasshopper that works within Rhinoceros, so that it will be possible to reassemble algorithms in an intuitive way for designers who have never experienced programming. Grasshopper is one of Graphical Algorithm Editor (GAE), and can be visually constructed an algorithm by connecting components that is a function of modeling. Analysis by gradient-based MP techniques often involves jumping of solutions and analytical instability peculiar to non-linear problems, and it is difficult to apply to the computer aided systems as described above. Analysis algorithms based on self-organizing algorithms are considered to be suitable for the above system due to their high robustness.

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