The vertical component of the ground motion recorded near the source in inland earthquakes occurred in Japan Island and the characteristics of the phase ground motion are studied. Also the vertical component of the ground motion synthesized using a thrust source model is studied. The curves for the Fourier spectral amplitude ratios of vertical to horizontal components are analyzed and summarized in terms of the mean and standard deviation of them for three surface soil conditions. Artificial vertical ground motions simulated using the proposed Fourier spectral amplitude ratios and the phase motions are compared with the records, in order to demonstrate an engineering capability of the proposed simulation method of vertical ground motions.

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 Authors proposed an estimation method of the site amplification factor for a site where earthquake records are not available by using microtremor H/V spectrum and the site amplification factor at a nearby site in the previous study. It is necessary to evaluate phase characteristics in addition to the site amplification factor for the evaluation of input design earthquake ground motion. This study discusses an evaluation method of phase characteristics for a site where earthquake records are not available considering the change in group delay time according to the change of peak frequency in the site amplification factor.

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 The main purpose of this study is to predict strong ground motions from future large earthquake for Karaj city, the capital of Alborz province of Iran. This city is an industrialized city having over one million populations and is located near several active faults. Finite fault modeling with a dynamic corner frequency has adopted here for simulation of future large earthquake. Target fault is North Tehran fault with the length of 110 km and rupture of west part of the fault which is closest to Karaj, assumed for this simulation. For seven rupture starting points, acceleration time series in the site of Karaj Caravansary -historical building- are predicted. Peak ground accelerations for those are vary from 423 cm/s² to 584 cm/s² which is in the range of 1990 Rudbar earthquake (M_w=7.3) . Results of acceleration simulations in different distances are also compared with attenuation relations for two types of soil. Our simulations show general agreement with one of the most well known world attenuation relations and also with one of the newest attenuation relation that hase developed for Iranian plateau.

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 Strong ground motions at the engineering bedrock for "Seismic Hazard Maps for Specified Seismic Source Faults" and "Probabilistic Seismic Hazard Maps" are evaluated using a strong motion simulation model (a detailed method) and an empirical attenuation model (a conventional method), respectively. In this study, spatial extents of isoseismal regions evaluated by both methods are compared for 158 cases of earthquakes occurring on major active faults. A multi-regression model is derived for prediction of the ratio of isoseismal areas (detailed / conventional) with independent variables such as moment magnitude, depths of the bedrock surface of deep sedimentary layers and average shear-wave velocities.

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 The method to determine the input strong ground motion is a key factor in the seismic performance assessment of road embankments. However, the procedure to choose the method is dependent on the experience and capability of the engineers. In this study, a questionnaire survey to 83 researchers and engineers of the earthquake engineering field in Japan is conducted to reveal their recognition on the features for various earthquake motion determination method. The procedure to conduct microtremor measurement for input strong motion determination and zoning judgement based on H/V spectrum obtained by microtremor measurements are also investigated. The results of the questionnaire are useful for a reference in practical earthquake motion determination for road embankments.

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 For dynamic analysis of structures, selection of ground motion (GM) is a crucial problem. For design, a tough GM should be used. It is difficult, however, to find such GM, because different GM can be the toughest in terms of different aspect. Uncertainty of structural properties complicates the problem. In this paper, an approach is presented to select design GMs out of a set of possible GMs using feature indices which are related with expected damage mechanisms of the structure. Uncertainty of nonlinear response is also incorporated. Quality of the GM selected in this scheme depends on the index considered. This paper discusses the efficiency of various indices through numerical simulations. Results verify the performance of the presented method and clarify several conditions to be taken into consideration.

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 In this study, the effect of uncertainty of phase characteristics of earthquake on variability of structure's nonlinear response was investigated. It is clarified that variation of nonlinear response is significant, and it is conspicuous as natural period of structure becomes longer. It consequently follows that the effect of uncertainty of phase characteristics should be properly taken into account when the estimation of strong ground motion is conducted for making design earthquake motion.

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 Tsukidate observing station of K-NET recorded acceleration of more than 27m/s² during The 2011 off the Pacific coast of Tohoku Earthquake. It is noted that the ground motions with long duration were observed in this earthquake. This study examines some of the characteristics of The 2011 off the Pacific coast of Tohoku Earthquake using nonlinear response analysis and nonlinear spectral analysis on the single-degree-of-freedom system. Based on the results of the studies, it is found that the ground motions in this earthquake have caused large response in the natural period of less than 0.5 seconds and smaller response than the current design codes in natural period range that affect the general bridges.

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 The seismic wave propagation simulation for the 2011 off the pacific coast of tohoku earthquake is per-formed using the voxel finite element method. In the simulation, the three-dimensional underground structural model is created for the vast area which includes the whole Eastern Japan region. The results show that since the seismic waves with large amplitude occurred on the east side of the source region propagate toward the offing of the Pacific Ocean, these large seismic waves are not reached to the Japanese Islands. On the other hand, although the seismic waves propagating toward southwest of the source region are relatively small, they are amplified by interfering with the seismic waves which occurred off Fukushima, and are propagated to the Kanto district with specific directivity. These seismic waves are subject to the influence of the deep sedimentary layers in the Kanto district, and are considered to become the ground motion of long duration time.

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 Time history records of ground acceleration and pore water pressure were obtained at a levee during the 2011 off the Pacific coast of Tohoku earthquake. The earthquake response of the levee is simulated by 1-D equivalent linear analysis and 1-D effective stress analysis using the ground motion recorded in the base layer as input motion. Frequency dependence of effective shear strain is taken into account to reproduce short period component of the response by the 1-D equivalent linear analysis. Hydrodynamic pressure and dissipation of pore water pressure are not reproduced by the 1-D effective stress analysis; freezing soil sampling and 2-D simulation may be required for improving the analytical results.

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 During 2011 off the Pacific coast of Tohoku Earthquake, strong ground motion caused serious damage to residences at Furukawa area in Miyagi Prefecture, north eastern part of Japan. Furukawa Gas supplies city gas in the damaged area, whereas no major damages were reported. Furukawa Gas manages a seismometer to monitor seismic intensity (SI), and the seismometor recorded the ground motion. However, only the later ground motion is available, and the main parts were missed. In this study, we estimate the main parts of the ground motion from the surrounding other ground motion records, aftershock records, and observed SI and PGA values by applying a time-frequency analysis.

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 We conducted four-day aftershock observation at Sanuma, Hasama-cho, Tome city, where roads and houses were subjected to severe damage during the 2011 off the Pacific Coast of Tohoku Earthquake. Using these aftershock records, we evaluated the difference of site amplification effects between Sanuma and nearby seismic stations, and estimated strong motion at Sanuma district during the main shock. The seismic intensity duirng the main shock at Sanuma was estimated as 7 with the JMA intensity scale.

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 SI value is often used as an index of ground motion for disaster estimation. Because source effect and site amplification effect have characteristics which depend on frequency, response spectra are effective in order to calculate the distribution of earthquake ground motion precisely. In the other hand, real-time estimation should be simple. In this paper, using the observation records in Yokohama, response spectra are estimated by the interpolation with the average ratio. It is shown that, 1)response spectrum is effective, 2)average S-wave velocity is well correlated to an amplification factor for the period range from 0.5 to 2.5 second, 3)the use of average ratio of response spectrum gives good estiomation of earthquake ground motion.

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 Underground motions within a hard diluvial stratum were obtained in the March 11th 2011 Great East Japan Earthquake at a downhole in the Tokyo Bay area, which has suffered serious sand-liquefaction over its long 42km² stretch. The motions in the diluvial sand deposit are characterized by their (1) long dura-tion times with 6 to 8s components surpassing others, (2) moderate amplitude of 51.1 cm/s² in PGA, which is estimated to have resulted in moderate average strains of 8 to 9 × 10^-4 and 5 to 7 × 10^-4 over shal-low -2 to -30m and deep -30 to -77m soil deposits, respectively. The peak strain reached in the interior of soil was estimated to be about 1.3 × 10^-3.

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 A phenomenon similar to a tsunami was observed by anglers and inhabitants at Saiko Lake, which is one of the five lakes located on the foot of Mt. Fuji, during the 2011 off the Pacific coast of Tohoku earthquake. In order to clarify the mechanism of this phenomenon, the author interviewed with the witnesses. The author also examined earthquake ground motions observed near the lake. As a result, surface wave exhibiting the nature of Rayleigh wave with the predominant period around 60 seconds in the observed motion which is coincident with a resonant period of the closed water body of Saiko Lake. A shaking experiment was conducted using a Saiko Lake model. It clearly explained the mechanism of a seismic seiche of Saiko Lake, which means that a resonant oscillation in the short side of the rectangular shape of the lake makes the shift to that in the long side. Then, the author concluded that the phenomenon was caused by a seismic seiche.

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 In the 2001 Tohoku-Pacific Ocean Earthquake (TPO-EQ), damage of railway structures were limited although the scale of earthquake was too large as compared with past large earthquakes. In this paper, relationships between properties of seismic waves and damage of viaducts were investigated. As a comparative example, 2003 Sanriku minami Earthquake(SM-EQ) was chosen, in which damage of viaducts was almost the same with that in TPO-EQ.
 Analytical results showed that difference of structural response were not significant although scale of earthquake were very different. In addition, it was found that structures located at damaged area observed in TPO-EQ showed 1.1 ~ 1.5 times larger response as compared in SM-EQ at the area, where severe damage was observed in TPO-EQ.

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 After a large earthquake, it is quite important to estimate strong ground motions at the site of damaged port structures to analyze damage mechanism and to determine restoration policy. Although several strong motion records were successfully obtained at damaged ports during the 2011 Great East Japan Earthquake Disaster (Takahashi et al., 2011), the records do not necessarily represent strong ground motions at the site of structural damage, because, according to recent knowledge, site effects can vary significantly within a relatively small area, even within a port. Thus, in this study, microtremor measurements and aftershock observations were conducted at damaged ports. The results of the study can be summarized as follows:
1) Gross distribution of the site effects within the ports were revealed at 8 ports where microtremor observations were conducted. At 7 ports (9 points), detailed site effects were revealed based on aftershock observations.
2) At Ofunato Port, it is estimated that the site effects are significantly different between the berthing facilities and the strong motions stations. The site effects for the berthing facilities were newly estimated based on aftershock records.
3) At Ishinomaki Port, the site effects at the berthing facilities are close to those at the K-NET strong motion station except for the Hibarino berth (-13m), the deepest berth in the port. The site effects for the Hibarino berth were newly estimated based on aftershock records.
4) According to the overall results, peak values of microtremor H/V spectra and those of site amplification factors are more or less correlated to each other.

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 Long-term continuous observation of ambient vibration/seismic motion is underway at the crest of an aged arch dam. The 2011 off the Pacific coast of Tohoku Earthquake occurred in the course of this long-term continuous observation, and the records of main shock, preshocks, lots of aftershocks were obtained, together with ambient vibration records before/after such events. Analyses of such observed data revealed the following;
1) System frequency identification method was applied, using ambient vibration data, which made clear that the proper frequency of the dam during about half a year from summer to winter became lower together with the dam surface temperature, suggesting that the both parameters are correlated positively with each other. On the other hand, it is inferred that the level change of water in the dam reservoir did not affect the above-mentioned proper frequency variation so much, as far as the example shown in this paper was concerned.
2) During the main shock of the 2011 off the Pacific coast of Tohoku Earthquake, observed record with very large maximum acceleration of about 630gal was obtained at the crest of the dam. The duration of the seismic motion of the main shock ranged about three minutes.
3) Spectral analyses of the main shock of the 2011 off the Pacific coast of Tohoku Earthquake and of ambient vibrations before/after the main shock revealed that the predominant frequency during the main shock became remarkably lower than the ones from the ambient vibrations before/after the main shock, and that the predominant frequency from the ambient vibration after the main shock returned back to the one before the main shock on the whole.
4) The phenomenon mentioned in 3) was confirmed to reappear also in the large-scale aftershock occurred on the 7^th of April, 2011.

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 In recent year, most of water pipe damages caused by earthquakes have been reported by pull out at joint. Ductile iron pipe are classified as mechanical type for earthquake-proof or non-earthquake-proof joint and slip-on type for non-e-proof joint. The earthquake proof joint never been damaged in the past earthquakes but the damage for another types of joint occurred frequently. Since the type of joint depends on the manufaction age and pipe diameter. Therefore, it could be estimated the relation between the damage rate and joint type. This paper focused on this issue. The resistance force against pull out at joint was clarified by the experiments and the results are discussed. Finally the earthquake adaptability for the different joint types is proposed.

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 Computing displacement from measured acceleration is important for understanding the characteristics of an earthquake. However, to obtain such displacement with a good accuracy is difficult. It is partly because the low-frequency component dominating the behavior of the displacement is often affected by the sensor's tilt and the measurement error. In this paper, a new methodology to get the acceleration without those undesirable effects is proposed. In addition, the integration method in frequency domain for computing displacement from the obtained acceleration is proposed, considering causality as a constraint to avoid the numerical error. Using these techniques, the estimation of residual displacement of the 2008 Iwate-Miyagi Nairiku Earthquake is attempted.

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 According to some of conventional studies focused on Fourier phase, it is pointed out that there are some examples in which Fourier phase characteristics of a ground motion from an aftershock of a past damaging earthquake is similar to that of a ground motion from the mainshock. This means that Fourier phase characteristics of ground motions from small earthquakes can be useful in order to predict ground motions from scenario earthquakes in the future. This paper presents, by using the 2003 Tokachi-oki earthquake (M_J8.0) as an example of a past damaging earthquake, the quantitative relation between the similarity with respect to Fourier phase characteristics of ground motions and the location of epicenters of small earthquakes which happened ofi Tokachi Region, Hokkaido, northern Japan.

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 Resolution of the phase velocity estimation methods, SPAC-, CCA-, nc-CCA-, and V-method, is investigated using microtremor data obtained with circular arrays of the vertical velocimeters deployed on the Osaka basin. The resolution of CCA- and V-methods in terms of maximum wavelength is more than twise as that of tha SPAC-method whenarray radius is less than 50 m. On the other hand, for tha array radius larger than 100 m, four methods show similar resolution in terms of maximum wavelength.

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 A shear wave velocity structure model of Padang, Indonesia was developed and the site amplification characteristics of earthquake ground motion were examined. The presented shear wave velocity structure model was obtained based on the microtremor survey. The inversion analysis of the dispersion curves of Rayleigh wave were performed for 11 sites where the array microtremor observations with 4 sensors were done and the shear wave velocity profiles were estimated for these sites. Furthermore the peak periods of HVSR for 130 sites were obtained and the distribution of the site dominant period was shown. The 3D shear wave velocity structure model was developed by considering the relation between the shear wave velocity profiles of 11 array sites and the site dominant period distribution. Finally the site amplification effect was investigated by conducting the finite element analysis.

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 The gravity survey is applied to model a ground structure. For this purpose, a spring-type relative gravimeter is usually used. Though this type of gravimeter can provide very accurate data, it is very expensive and difficult to handle. This means that a simple and inexpensive sensor to measure the gravity is required. For this, we began to develop a new gravimeter using a force-balanced-type accelerometer. In this study, we develop a preliminary system and calibrate it. Then, a simple measurements is carried out on an observation wheel, on a car, and on a ship. The gravity data is contaminated by vibration of carriers, though we found a technique of blind source separation can be hopeful to pick up gravity data from the observed data. However, we also recognized some problems that needs to be solved.

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 Peaty ground deposited in the northern part ofJapan, especially Hokkaido is so soft that it causes the ground deformation and uneven settlement to the housing lot and the damage to pipeline at an earthquake. This study focuses on Urakawa, Hokkaido, which experienced water supply outage due to the pipeline damage both in the 1982 Urakawa-off earthquake and in the 2003 Tokachi-off earthquake. Seismic response of peaty ground was analyzed based on the result of surface wave test investigated. Not only irregular subsurface ground including peaty ground and underlying soft ground but also softness of the peaty ground is considered to affect damage to the water pipeline.

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 In the current seismic design of underground structure, only earthquake shaking is considered and the influence of fault displacement is not considered. However, since linear underground structure such as tunnels have a possibility to be constructed across faults, they have a probability to get severe damage due to the fault displacement. In this study, Soil-underground structure-seismic fault model is analyzed by 3D finite element analysis considering slip and exfoliation between structure and the effect of fault displacement on the underground structure are evaluated. Further more the applicability of the earthquake resistant joints used for underground structure as countermeasure of ground excitations to fault displacements are studied by the numerical analysis, and it is clarified that the more increasing the number of joints and the decreasing of the space of joints introduce the more reducing of cross sectional forces.

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 Severe soil liquefaction due to long duration earthquake with low acceleration occurred at Tokyo Bay area in the 2011 off the Pacific coast of Tohoku Earthquake. This phenomenon clearly shows that soil liquefaction is affected by properties of input waves. This paper describes effect of wave properties of earthquake on liquefaction using Effective Stress analysis with some earthquakes. Analytical result showedthat almost the same pore water pressure was observed due to both long durationearthquake with max acceleration of 150Gal and typical inland active fault earthquake with 891Gal. Additionally, lique-faction potentials for each earthquake were evaluated by simple judgment with accumulated damage parameter, which is used for design of railway structuresin Japan. As a result, it was found that accurate liquefaction resistance on large cyclic area is necessaryto evaluate liquefaction potential due to long duration earthquake with low acceleration with simple judgment with accumulated damage parameter.

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 The coast area in Tokyo-wan which is far from the earthquake fault, were heavily liquefied during the 2011 off the Pacific coast of Tohoku earthquake. It is very important to predict the occurence and degree of liquafaction, because the liquafaction affects the safety of underground pipilines and facilities of roads and ports. The real-time disaster prevention system "SUPREME" is established and used by Tokyo Gas supply system in order to secure the safety. The system collected the SI value from 4,000 sensor, calculated the distribution of SI value, liquafaction potencial, damages of pipelines for about 20 minutes after the earthquake. In this paper, it is shown that estimated liquafaction area corresponds actual liquafaction area very well, and the reason is that "SUPREME" uses very dense SPT data and SI sensors and the estimate method of liquafaction considers the effect of duration time of earthqauke groun motion.

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 Liquefaction occurred in a wide range of reclaimed land in Tokyo Bay. Features of the damage which occurred a large amount of sand boiling. In this report, the boiled sand grain characteristics, Permeability characteristics. We conducted experimental model to measure the amount of sand boiling. Test results, Urayasu-sand(Fc=36%), soil and water erupted along. Toyoura-sand(Fc=0%) is the only water erupted. As a result, fine-grained soil is found to be a large amount of sand boiling.

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 It is generally known that liquefaction strength obtained from undrained cyclic triaxial test is influenced by various factors such as relative densities, fine content, grain size distributions and plasticity indexes. However, It is difficult to estimate liquefaction strength for various soil types from same physical properties. In order to estimate the liquefaction strength of various soil types such as silt, silty sands and clean sands, this study showed a method to revice relative density of sandy soil including more than 15% of fine content and the correlation between reviced relative density and void ratio ranges obtaind from maximum and minimum void ratio. Then, the relationships between void ratio ranges and liquefaction strengths from other studies was considered. As a result, the defference of liquefaction strength between reconstituted and undisturbed samples was recognized from the correlations revised relative density using void ratio ranges and fine content.

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 The 2011 East Japan Great Earthquake caused soil liquefaction over a wide area. In particular, severe soil liquefaction was reported in the northern parts of the reclaimed lands around Tokyo Bay, even though the seismic intensity in this area was only about 5 on the Japan scale with low acceleration. The authors surveyed the residual settlement in the Urayasu district and then conducted effective stress analyses of areas affected and not affected by liquefaction. The analyses compared with the acceleration waves monitored with K-NET Urayasu or ground settlements surveyed. It is based on the acceleration observed on the seismic bedrocks in earthquake engineering in some other districts adjacent to Urayasu. Much of the settlement was due to the long duration of the earthquake, with further settlement resulting from the aftershock. The study shows that the affects of aftershocks need to be monitored, as well as needs for improvement of simplified liquefaction prediction methods using the factor of safety, F_L.

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 In order to reduce discrepancies between ground models based on the microtremor array observation in Fukui Plain and models by the H/V survey method and gravity analysis, the existing array ground models were reevaluated. The representative of the dispersion curves was selected so as to fit a theoretical fundamental mode dispersion curve of the H/V ground model. By using the method of selection, a reasonable reevaluation became possible. As a result the correspondences among the three models were much improved as a whole, but in the edge site of the Plain the differences against the gravity model are not reduced.

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 Slope failure occurred in an embankment of the Joban expressway during the 2011 off the Pacific coast of Tohoku Earthquake and its largest aftershock. Therefore, the evaluation of strong seismic motion at this site with high accuracy is very important to clarify the failure mechanism. In this study, the seismic waveform at this site was estimated based on empirical site amplification and phase effects. The estimated seismic waveform will be useful for rational safety assessment of road embankments.

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 The mission of an airport during and after a great earthquake is important from a standpoint of its helpful function for emergency special operations of transporting relief supplies to the disaster area. However, it is expected that the function of runway will be lost due to differential subsidence and decrease in bearing capacity of the ground with excess pore water pressure induced by earthquake. In this paper, in order to estimate the bearing capacity of ground after liquefaction, a series of CBR tests and field tests were conducted. This paper describes the influence of excess pore water pressure to bearing capacity of runway ground during and after liquefaction.

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 The seismic deformation characeteristics of a pile supported pier was examined with the shake table test, especially focusing on the pier after its deformation during earthquakes. The model based on the similitude of the fully-plastic moment in piles was prepared to confirm the deformation and stress characteristic after reaching the fully-plastic moment. Moreover, assuming transportation of emergency supplies and occurrence of after shock in the post-disaster period, the pile supported pier was loaded with weight after reaching fully-plastic moment and excited with the shaking table. As the result, it is identified that the displacement of the pile supported pier is comparatively small if bending strength of piles does not decrease after reaching fully-plastic moment due to nonoccourrence of local backling or strain hardening.

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 The liquefaction-induced ground displacement in sloped ground occurred during past earthquakes. Therefore, if liquefaction occurs in the seabed in front of seawall, the slope may make displacement of the seawall increase. A shake table test of a large model was conducted in order to understand seismic response of seawall and sloped seabed during an earthquake. As a result, displacement at the top of the seawall was not received influence of sloped seabed but the seabed moved greatly to sea side by movement of the seawall and displacement of the seabed was increased by the slope.

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 "Ground response spectrum" is proposed in this paper. "Ground response spectrum" is the graph which is so drawn as to read the maximum values of dynamic responses of subsurface ground to a seismic accelerograph, such as particle acceleration, velocity, displacement on the surface and shear strain caused in the ground. The calculation method of the spectrum is the same as the ordinary response spectrum except the use of simple one-dimensional continuum of linear viscoelastic medium; instead a single-degree-of-freedom oscillation system is used in the calculation of ordinary response spectrum. A few examples of the "ground response spectrum" are presented and special feature and usefulness of the spectrum is discussed in this paper.

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 Equivalent linear analysis is often applied in the analysis of ground response to earthquakes for its simple setting of input parameters, such as nonlinear characteristics, and for its computational stability. However, as the accuracy of analysis based on this method deteriorates with greater ground nonlinearity, the range of application should be taken into consideration when the technique is used. Accordingly, equivalent linear analysis was performed on a single site using different levels of input earthquake motion to examine the method's applicability using maximum shear strain as an indicator. The results showed that a maximum ground shear strain value exceeding 1 × 10^-3 resulted in a trend toward reduced reproducibility of maximum acceleration. In the frequency domain level from 0.2 to 2.0 Hz, equivalent linear analysis is considered to be applicable even when the maximum shear strain extends up to 2 × 10^-3.

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 This paper demonstrates the efficiency of micro-earthquake observation for estimation of 3-D structure of a landslide block and evaluation of seismic response properties of a landslide site, showing an example of such an observation conducted at a national famous landslide area at Choja in Kochi Prefecture, Japan. First, we show that it is quite difficult to explore the landslide site in terms of underground S-wave velocity structure by conventional microtremor measurement because of extremely low level of ambient vibration. Next, we show that a three-day observation of micro-earthquake is effective for obtaining some recognizable micro-earthquake motions at the landslide site. Finally, we demonstrate that predominant frequencies specified according to the spectral amplification of the micro-earthquakes can be obtained at three observation points locating inside of the landslide block, and that depths of a sliding plane estimated by multiple reflection theory for one-dimensional soil column with both the predominant frequencies and the S-wave velocities obtained through multi-channel surface wave exploration agree with actual ones referred from a literature with 15% error.

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 Accurate evaluation on the seismic response characteristics of a road embankment is very important for the rational seismic assessment. However, in a lot of previous studies, the seismic response characteristics of an embankment were evaluated based on the results of shaking table test, centrifuge model test and dynamic FEM analysis. In this study, the transfer function and the shear wave velocity of a road embankment were evaluated based on the in-situ records of moderate earthquake observation and microtremor measurement. Test results show the possibility that the shear wave velocity of an embankment can be estimated by the earthquake observation or the microtremor measurement and the dynamic linear FEM analysis.

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 In the present design of power poles on viaducts of railway, seismic response is calculated using response of viaducts as input force. Since viaducts damaged during earthquake show plastic deformation behavior, natural period of tends to be longer and response may be reduced. Therefore, it is considered that input force given to power poles may be smaller during large earthquake. Additionally, power poles may show very large response with small earthquake if they resonate with viaducts.
 In this paper, analytical study was conducted to know the effect of properties of seismic input waves on the seismic response of power poles on railway viaducts. Analytical results showed that seismic response of power poles may become very larger even if input seismic wave is small.

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 The present paper examines the applicability of the FEM-DEM combined method for the large-scale seismic response analysis of a pipeline hanging on a base-isolated bridge. In particular, the seismic response analysis of a steel pipeline used as a telecommunication cable conduit was conducted and its dynamic large deformation and fracture behavior was determined. From the analysis results, an effective countermeasure is proposed, which involves the use of an expansion joint and a separation preventer at the screw joint of the steel pipeline.

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 It is well known that skewed bridges tend to rotate and collapse under the strong seismic excitation. This paper clarified the requirement for rotation of skewed bridges including straight bridges considering the gap between a deck and an abutment. Then, deck rotation response of skewed bridges in which the deck can uplift from its bearings is studied. It is shown that the skewed bridges are likely to rotate more extensively, if uplift of the deck from bearings is allowed to occur.

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 Dynamic analysis is widely used for the seismic design of the bridge with horizontal force distributed structure in recent years. There is few research on dynamic analysis of such bridges using real earthquake data. In this research, we carried out dynamic analysis using accelerograms recorded during the 2011 off the Pacific coast of Tohoku earthquake (M_w9.0). The analytical earthquake response shows a good agreement with the observed response when colliding and friction forces acted between sideblocks and shoes are taken into account.

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 For the purpose of seimic performance vertification of bridges in the process of seismic design, it is desirable to use spectrum-compatible bi-directional accelerograms with well-established multi-dimentional characteristics. In this paper, a method of generating spectrum-compatible bi-directional accelerograms by means of the complementary normal component wave computed by application of the Hilbert transform to standard accelerograms often provided by design specifications. It is shown that the intensity of the bi-directional input generated by this method is equivlent to that of the comventional unidirectional input with respect to the elastic response spectrum. Particular features of the effect of bi-directional input to structural model is examined with numerical dynamic response analysis of a simplified bridge model consisting of a superstructure, a seismic isolator and a seismic damper, and the difference of the evaluated structural responses between the bi-directional and unidirectional input cases appears, for which the degree of the effect depends on the type of standard earthquake accelerograms.

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 The objective of this paper is to discuss the causes of asymmetric response of superstructure using the elasto-plastic model considering the influence of P-Δ effect and simplified periodic motion of real ground motion record. The inelastic behavior subjected to the input ground motion is so complicated that it is estimated in this paper by using the procedure to simplify the ground motion. In this study, in order to establish the simple seismic design method considering the asymmetric response. We investigate the nonlinear response characteristics using four types of nonlinear model. The superstructure itself is idealized as a single degree freedom system attached to a rigid spread foundation with two degree of freedom which is flexibly supported. We defined that simplified periodic motion is effective to explore asymmetry of response. The response behavior and residual displacement differ with each period of models.

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 Seismic response of an open type wharf with pneumatic caisson was clarified using a dynamic finite element method. As a result, rocking behavior of caisson foundations were observed and applicability of a frame model analysis to the earthquake resistant design of a wharf was suggested. Authors proposed the framework of earthquake resistant design method of the wharf including the evaluation method of response acceleration of the wharf.

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 This paper discusses the applicability of ground response acceleration method to seismic analysis for deep vertical underground structures. To examine the applicability, an analysis of relationships between response of ground and the shaft was conducted. It was found from the analysis that vertical axial stress of the shaft was not correspond with shear stress of ground. Accordingly, it was concluded that the axial stress was not evaluated correctly by the existing method. Therefore, to extend the applicability of the method, ground responses correlated with the axial stress were analyzed and a new method using these ground responses was proposed.

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 Recently, long-period and long-duration time seismic waves caused by huge ocean-trench earthquakes have been observed in Japan, and a few dozen to several hundred times of cyclic shaking were occurred after principal motion in these waves. However, seismic performances of structures subjected to long-duration time motions are not clear. Therefore, this paper discusses the load bearing capacities of steel bridge piers during dozens of cyclic loading. Cyclic load carrying tests and a pseudo-dynamic test were carried out in order to investigate the cyclic load bearing capacity of steel bridge piers. Moreover, complex nonlinear analyses were conducted to simulate the experimental tests. Consequently, it is found that the load bearing capacity after maximum load is decreased about 10% due to cyclic loading over 10 times. Furthermore, numerical analyses have shown a part of the reason for deterioration of load bearing capacity after maximum load.

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 In order to grasp effects of foundation and superstructures on seismic behavior of existing steel bridge frame piers, frequency analysis and elasto-plastic FEM earthquake response analysis by considering foundation or superstructures in the FEM models were carried out. Based on the author' previous research, a 2-story type frame pier was used as object frame piers. As a result, effects of foundation on seismic behavior in the transverse direction of the 2-story frame pier were not so significant after applying concrete filling. Moreover, effects of superstructures on seismic behavior in the longitudinal direction of the 2-story frame pier were beneficial. However, their effects on the seismic behavior in the transverse direction are not so significant. Thus, seismic performance of existing frame piers can be applicably evaluated by seismic performance evaluation in the transverse direction.

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