In the design standards for railway structures (revised in 2012), the concept of “Anti-catastrophe” has been introduced in order to prevent the occurrence of catastrophic states against earthquakes of an unanticipated scale. In this paper, the dead weight compensation mechanism to be applied to enhance the anti-catastrophe performance of viaducts is proposed. The anti-catastrophe performance is achieved by maintaining the vertical support performance even during an extreme earthquake event. The seismic performance and feasibility of the proposed mechanism for railway bridge structures are investigated by loading test. As a result, the structure with the proposed mechanism is confirmed to satisfy the requirement of seismic performance and no loss of vertical support performance of the structural system.

 During the 2016 Kumamoto earthquake, a lot of structures including bridges suffered significant damage. A superstructure of some curved bridges in mountain area was dislocated horizontally and this damage could be due to the pounding at the deck end because there was an evidence of the pounding from the field investigation. Therefore, this paper presents an analytical investigation of a curved bridge located in mountain area with an emphasis on a deck rotation subjected to a near-field ground motion. A three span continuous bridge having 250m deck curvature was analyzed by a 3D fiber element model considering a deckabutment pounding interaction to simulate the behavior of the curved bridge. The analytical results showed that the curved bridge superstructure tended to rotate horizontally, as compared to the straight bridge, due to the deck-abutment pounding.

 This paper presents the development of a new seismic design concept that a plastic hinge zone of a reinforced concrete column can be repairable after its damage under level 2 earthquake ground motions. In order to validate this proposed new seismic design concept, an experimental investigation was conducted. Two scaled model columns, a conventional and new proposed reinforced concrete column, were constructed for cyclic loading tests. The new column could reduce residual displacement as compared with the conventional one although the residual displacement was still large for column restoration. The experiments confirmed that the new column could be repairable after its damage of the plastic hinge zone subjected to large deformation.

 In 2018, seismic intensity of 3.0 was observed in the Tarumi district northern Osaka-fu earthquake. During the seismic activity, a behavioral reproduction analysis was held by 6 seismographs installed at six places targeting the Myotani bridge. The aim of this study is to estimate the behavior of nonlinear dynamic analysis model, generally used in earthquake resistance analysis, and to explain the factors that produce the discrepancy between the analysis results and the actual behavior. The study was held by comparing the waveform measured in the bridge (the superstructure, the piers and foundations), and the waveform measured in the ground surface which was used as input earthquake motion. Also, in order to perform the analysis, vibration position in the ground’s input motion and the support conditions of the bridge, were used as parameters in the model. From the testing results, it was possible to understand that the vibration characteristics of the bridge were able to be reproduced, despite the acceleration and the displacement were not equal. However, some problems were found in the modeling of the resistance characteristics of the ground and the bearing conditions, when reproducing the actual behavior of the bridge.

 In recent years, large-scale earthquakes such as the Great East Japan Earthquake and the Kumamoto earthquake occurred in our country. At the time of the earthquake disaster vulnerable people like infants are difficult to evacuate by themselves, Cooperation between Childcare institutions staff and parents is essential for infant. In particular, when an earthquake occurs when a parent leaves an infant in a Childcare institution, In order to eliminate anxiety about parents and staff and to pass smoothly, it can be said that it is important to grasp each other's actions in advance.

 In this study, a questionnaire survey was conducted for guardians who leaving infants in Ishikawa, Childcare institution from the time of earthquake to pass of infant, it cleared what kind of behavior is assumed at what timing.

 Recently, large-scale disasters are occurring frequently in Japan. It is inevitable that food-problems are occurring in the event of large-scale disaster. For this reason it is important to prepare for natural disasters. Since the Great East Japan Earthquake, limits of public assistance are pointed out. Therefore, it is important that we try to promote self-help and mutual assistance for people to improve the disaster prevention power in Japan. In this study, the possibility of self-help and mutual assistance which aimed to Kanazawa city, Japan was analyzed using the basic unit of household-food and stored stock of retail store. As a result of this study, it was revealed that there is enough food to support self-help and cooperation for 4 days, and there is only drinking water that can not be covered by self-help as of the first day of disaster.

 Authors carried out hydraulic experiments to clarify the dependency of passage rate, blocked rate and residual rate of tsunami floating bodies to or on a bridge deck upon tsunami peak velocity and tsunami averaged velocity, and inundation front height and rear height of a bridge deck. The share of passage rate of tsunami floating bodies with impact to a bridge deck and without impact of a bridge deck when tsunami peak velocity increases was clarified and in contrast physical mechanism on blocked rate of tsunami floating bodies to a bridge deck was discussed. In addition, residual rate of tsunami floating bodies on a bridge deck was found to become about 10% - 20% which is dominant of relatively small-sized tsunami floating bodies when tsunami peak velocity becomes high.

 In order to assess the possibility of dense seismograph network, applicability of the compact and low price MEMS chips to seismic observation network was investigated. MEMS and conventional servo type seismograph were installed all together at the experimental site in the Kanto region. It was found that the low frequency noise was mixed in the observation record by MEMS. Regarding the PGAs and instrumental seismic intensities, there was little difference in the both sensors. On the other hand, PGVs and SI-values obtained from MEMS were overrated in case of small values. From the comparison of time histories, the records of MEMS did not show good agreement with the servo type seismograph’s records whePGAs were less than about 20 cm/s2.

 In this paper, evaluation method for sliding displacements of embankment is proposed considering its dynamic response characteristics. First, the method to identify response characteristics of both embankment and its sliding block was proposed. Second, evaluation method of sliding displacements was proposed by employing nonlinear dynamic response analysis with equivalent single degree of freedom model. Finally, accuracy of the proposed method was confirmed by numerical simulations. The proposed method makes it possible to easily estimating the seismic response of the embankment considering its vibration characteristics. This method is applicable for seismic design of railway system having numerous amount of embankment. In addition, the proposed method complies with that for bridges and viaduct, enabling to compare obtained results with those of other structures.

 An approach for monitoring real time seismic intensity distribution using seismic intensity network maintained by a local government is demonstrated. Dense observation network is desirable for upgrading accuracy and quality of Earthquake Early Warning System. Seismic intensity meters in Tottori prefecture are improved to broadcast packets with peak ground acceleration and JMA seismic intensity at every one second. The data are received at Tottori University and modified PLUM method is applied for estimating real time JMA seismic intensity distribution. Using the system, more detailed seismic intensity distribution than before is estimated, since we can use 34 seismic intensity meters in Tottori prefecture but only 6 observation sites in the area are used for usual earthquake early warning by JMA.

 After the 2011 Tohoku Japan earthquake, importance of disaster prevention countermeasures from soft infrastructure perspective is highlighted. The local governments revise their hazard maps to raise people’s awareness of disaster prevention. However, the hazard map is not sufficiently used among the local residents. This research develops a mobile app for Android devices to visualize the hazard map using augmented reality technology. The tsunami inundation depth and the location of evacuation site are displayed on a smartphone screen with the image captured by phone’s camera.

 The concept of “Anti-Catastrophe” has been proposed after The 2011 Tohoku Earthquake. This concept is not necessarily a new idea for seismic design, it is considered in existing design code in various parts. However, there are many parts that are not expressed explicitly, examples that do not reflect intent of this concept are also found in actual structures.

 This paper is organized for the purpose of introducing this concept into seismic design for bridges, we discuss feasible methods and problems to realize this concept.

 An earthquake (Mj6.1) occurred in the vicinity Ohda city western Shimane Prefecture in Japan on April 9, 2018. We conducted aftershock (strong motion) observation at several temporary sites in the area with housing damages. Characteristics of site amplification effect of the temporary sites were understood from analysis of seismic data. Also, microtremor observations were carried out to estimate the characteristic of ground vibration in the damage area. Microtremor H/V spectra and a distribution of the predominant period were obtained from observation data. In addition, we checked the relationship between site effects S-wave velocities, H/V of microtremor and strong ground motion. As a result, it was found that maximum thickness of the weak soil subsurface layer is 40m and a short period component of predominant period about 0.2-0.4 seconds may have influenced structural damage.

 The importance of ensuring telecommunication even in the event of a large-scale earthquake that occurred in recent years has increased, and earthquake countermeasures for communication conduits have become an issue. On the other hand, damaged conduits are limited, and it is not efficient to implement measures for all. Therefore, it is necessary to identify conduits that are more likely to suffer disasters and implement countermeasure. Screening methods have been proposed to classify groups by using lengths, types, micro topography classifications and PGV, and to extract groups suspected of being vulnerable in past studies. In this paper, we focused on the types, sizes and shapes of manholes connected to both ends of a conduit, which we have not focused on, aiming at sophistication of this screening method. Based on the results of this tabulation, we will consider three points, as candidates for new features of pipeline which are easily affected by damage, those with relatively large numbers, those made of resin concrete, those with branched shapes.

 In this paper, we analyzed the effect of artificial viscosity on the landslide flow distance in the Smoothed Particle Hydrodynamics (SPH) method. Moreover, to show the applicability to an estimation of flow distance, we conducted a two-dimensional simulation of the Aratozawa landslide. As a result, we obtained good agreement with actual damage of flow distance and residual deformation by reducing residual internal friction angle until the shear resistance angle with pore water pressure. It showed that the SPH method considering artificial viscosity could be applied to geo-disasters with large deformation of liquefied ground, such as earthquake-triggered landslides, the lateral spread of liquefied ground, et al.

 Generally, it is thought that occurrence of excess pore water pressure in liquefied ground leads to the loss of shear strength and shear modulus. After liquefaction, It is well known that shear strength and shear modulus of the liquefied ground were restored until the initial state before earthquake with dissipation of excess pore water pressure. However, it has been rare to report observational results based on ground investigations to compare the ground state changes after earthquake systematically. In this paper, the change of the liquefied ground properties after earthquake was investigated based on the previous ground survey. As a result, it was found that the liquefied ground properties do not necessarily synchronize with the excess pore water pressure dissipation, but returning to the initial state before the earthquake under the long-term recovery tendency.

 On the Kumamoto earthquake in 2016, a pre-quake on April 14 and a main shock on 16th occurred. In Kumamoto city, damage to buildings, residential land, roads and lifeline occurred due to liquefaction of the ground. In Kumamoto city, about 2, 900 residential lots caused severe damage to building sinking and slope due to liquefaction. Particularly in the Chikami district to kawashiri district, remarkable subsidence and inclination of the building occurred on the line due to the liquefaction of the foreshock and the mainshock. In this paper, I analyzed liquefaction damage survey and questionnaire survey in Chikami district. As a result, the liquefaction revealed the relationship between the building structure / floor number, basic structure and building sinking / slope.

 From the damage experience that occurred at large earthquakes, studies on basic performance and seismic performance on rubber bearings become active. In particular, data accumulation for actual rubber bearings are useful for understanding actual behaviors.

 In order to investigate the loading direction of deformation behaviors on rubber bearings, this study performed loading test of actual super high damping rubber bearing. This study compared the deformation behavior on the loading direction of 0° and 45° by horizontal uniaxial testing. As a result, hysteresis loops of 0° agrees well with that of 45°, and this result is similar to the results of the previous study.

 In this study, by using simultaneous observation record at neighbouring earthquake ground motion observation stations, the variations of the site amplification factors was evaluated with IBR003 earthquake ground motion observation stations in Ibaraki prefecture. Furthermore, the earthquake ground motion considering the variation of the site amplification factors was calculated, and the relation between the variation of the site amplification factors and the variation of representative values of earthquake ground motion was discussed.

 As a result, the peak ground accelerations, peak ground velocities, and power spectrum intensity values of the earthquake ground motions considering the average site amplification factor are smaller than the average values of those of the earthquake ground motions.

 In this study, we investigated the applicability of earthquake response analysis using Smoothed Particle Hydrodynamics (SPH) method for simulating progressive slope failures induced by earthquakes. The SPH method is a large deformation analysis method of a continuous body that utilizes the elasto-plastic constitutive model and is possible to analyze a slope failure induced by earthquake ground motion. A progressive slope failure is a form of slope collapse in which the deformation of the slope is induced only when the earthquake ground motion is in effect. In this study, we investigated the effect of the period of input seismic motion and the material strength on progressive slope failures by carrying out the earthquake response analysis of the slope models by use of the SPH method. Furthermore, by conducting small deformation analysis by SPH method, we showed that large deformation analysis by SPH method is effective in seismic response analysis for progressive slope failure.