On April 25, 2015, a M w 7.8 earthquake struck the Gorkha district of Kathmandu, Nepal. In Patan,... more On April 25, 2015, a M w 7.8 earthquake struck the Gorkha district of Kathmandu, Nepal. In Patan, vibrational characteristics of a 300-year-old two-story masonry building near Patan Durbar Square had been measured prior the Gorkha earthquake. In the inspection of the building after the Gorkha earthquake, several new cracks were found. The vibrational characteristics of the building were measured again, and it was found that the natural frequencies after the earthquake were smaller than those before the earthquake, indicating the reduction of the stiffness. Finite element models of the structure representing pre-and post-earthquake conditions are established so that the natural frequencies match the pre-and post-earthquake measurements and the structural damage is identified based on the stiffness reduction. Finally, the dynamic analysis of the finite element model of the building in the pre-earthquake condition using the observed ground motion record during the Gorkha earthquake as the input is conducted, and the structural response of the building during the Gorkha earthquake is discussed.
We propose a circular path and linear momentum method for the seismic response analysis of vehicl... more We propose a circular path and linear momentum method for the seismic response analysis of vehicles. This method considers the momentum induced by earthquake excitation and applies the concept of centripetal force acting laterally on the vehicle in addition to longitudinal forces. This method is valid for vehicles at rest as well as those moving at a range of speeds. The vertical responses are calculated using a quarter vehicle model. We also calculate the translational motion of the vehicle using a model with six degrees of freedom. Three vehicle types (car, bus, and truck) were used in the analysis. We compared the result with analysis of the response of a shaking vehicle from video footage recorded during the Gorkha earthquake. We used the input ground motion from 10 large earthquakes of moment magnitudes 6.7-9.0. All three components of the ground motion were used in the analysis. Vehicles at rest and moving at various speeds were analyzed. The lateral and longitudinal responses of the vehicles were calculated for different vehicle speeds ranging from 0 to 30.0 m/s, PGA excitations and orientations of the vehicle.
Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 2012
工) 京都大学大学院工学研究科 准教授 (〒615-8540 京都市西京区京都大学桂) **京都大学大学院工学研究科修士課程 (〒615-8540 京都市西京区京都大学桂) ***博(工) 京都... more 工) 京都大学大学院工学研究科 准教授 (〒615-8540 京都市西京区京都大学桂) **京都大学大学院工学研究科修士課程 (〒615-8540 京都市西京区京都大学桂) ***博(工) 京都大学大学院工学研究科 教授 (〒615-8540 京都市西京区京都大学桂) ****立命館大学歴史都市防災研究センター教授 (〒603-8341 京都府京都市北区小松原北町 58) In this study, we propose a method to consider deformability of elements for a failure analysis of masonry structures using the DEM. In the original DEM, the deformability of the structure can be modeled by overlapping between rigid elements, but Poisson's effect cannot be modeled. In the proposed method, an element is divided into two parts, an inner part to consider deformation of the element itself, and an outer part to deal with contact between elements. The stiffness of the inner part is modeled using the stiffness matrix of the finite element method. When two elements are continuous or in contact, springs are set between the elements and the spring constants are estimated based on the original DEM and the length of the outer part. The validity of the method is confirmed through the comparison of elastic deformation with the FEM. It is found that the original DEM and the proposed method show different failure patterns, and considering the deformability of element is found to be necessary.
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 2014
Regarding 2011 Tohoku Earthquake and Tsunami, more than 20,000 people were killed or missing. In ... more Regarding 2011 Tohoku Earthquake and Tsunami, more than 20,000 people were killed or missing. In addition, more than 90% of killed people were due to tsunami. Many people could not or did not evacuate from tsunami despite enough evacuation time and warning information. The awareness of danger in a community increases by not only information given by the governments and the mass media but also behaviors of people in a community. After their awareness reaches their upper limit, they start evacuation. In this study, authors developed the simulation model for the initiation process of community's tsunami evacuation focusing on awareness of danger in a community. Authors verified the model with simple conditions, and validated in the case study of an elderly care facility which was attacked by the 2011 Tohoku tsunami.
Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 2013
Fundamental study on a simple evaluation method of seismic safety of road embankment structures 古... more Fundamental study on a simple evaluation method of seismic safety of road embankment structures 古川愛子*，水上輝**，清野純史*** Aiko FURUKAWA, Akira MIZUKAMI and Junji KIYONO *博(工) 京都大学大学院 地球環境学堂 准教授(〒615-8540 京都市西京区京都大学桂) **京都大学大学院 地球環境学舎 修士課程(〒615-8540 京都市西京区京都大学桂) ***博(工) 京都大学大学院 地球環境学堂 教授(〒615-8540 京都市西京区京都大学桂) This study proposes a simple evaluation method of seismic safety of road embankments. The safety of the embankments is confirmed by comparing the analyzed sliding displacement with the allowable displacement. The method is simple, but it has the equivalent accuracy with the Newmark method. The proposed method consists of two-step evaluations. In the first step, the method uses the equivalent yield acceleration, which is the PGA of ground motion whose sliding displacement reaches the allowable displacement. The method extracts the embankments which have the possibility to slide longer than the allowable displacement. In the second step, the method easily calculates the sliding displacement assuming the planar sliding surface for all embankments extracted in the first step. The validity of the method was confirmed by the numerical simulation.
The Great East Japan Earthquake exerted serious damage over an unprecedentedly wide range. The ea... more The Great East Japan Earthquake exerted serious damage over an unprecedentedly wide range. The earthquake prevented the supply of materials indispensable to restoration and revival in its aftermath, including fuels such as gasoline. In this study, we apply a system dynamics solution to investigate the causes and bottlenecks of this problem in order to ameliorate similar problems in wide-ranging disasters that are expected to occur, such as the Huge Nankai Trough Quake.
On April 25, 2015, a M w 7.8 earthquake struck the Gorkha district of Kathmandu, Nepal. In Patan,... more On April 25, 2015, a M w 7.8 earthquake struck the Gorkha district of Kathmandu, Nepal. In Patan, vibrational characteristics of a 300-year-old two-story masonry building near Patan Durbar Square had been measured prior the Gorkha earthquake. In the inspection of the building after the Gorkha earthquake, several new cracks were found. The vibrational characteristics of the building were measured again, and it was found that the natural frequencies after the earthquake were smaller than those before the earthquake, indicating the reduction of the stiffness. Finite element models of the structure representing pre-and post-earthquake conditions are established so that the natural frequencies match the pre-and post-earthquake measurements and the structural damage is identified based on the stiffness reduction. Finally, the dynamic analysis of the finite element model of the building in the pre-earthquake condition using the observed ground motion record during the Gorkha earthquake as the input is conducted, and the structural response of the building during the Gorkha earthquake is discussed.
We propose a circular path and linear momentum method for the seismic response analysis of vehicl... more We propose a circular path and linear momentum method for the seismic response analysis of vehicles. This method considers the momentum induced by earthquake excitation and applies the concept of centripetal force acting laterally on the vehicle in addition to longitudinal forces. This method is valid for vehicles at rest as well as those moving at a range of speeds. The vertical responses are calculated using a quarter vehicle model. We also calculate the translational motion of the vehicle using a model with six degrees of freedom. Three vehicle types (car, bus, and truck) were used in the analysis. We compared the result with analysis of the response of a shaking vehicle from video footage recorded during the Gorkha earthquake. We used the input ground motion from 10 large earthquakes of moment magnitudes 6.7-9.0. All three components of the ground motion were used in the analysis. Vehicles at rest and moving at various speeds were analyzed. The lateral and longitudinal responses of the vehicles were calculated for different vehicle speeds ranging from 0 to 30.0 m/s, PGA excitations and orientations of the vehicle.
Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 2012
工) 京都大学大学院工学研究科 准教授 (〒615-8540 京都市西京区京都大学桂) **京都大学大学院工学研究科修士課程 (〒615-8540 京都市西京区京都大学桂) ***博(工) 京都... more 工) 京都大学大学院工学研究科 准教授 (〒615-8540 京都市西京区京都大学桂) **京都大学大学院工学研究科修士課程 (〒615-8540 京都市西京区京都大学桂) ***博(工) 京都大学大学院工学研究科 教授 (〒615-8540 京都市西京区京都大学桂) ****立命館大学歴史都市防災研究センター教授 (〒603-8341 京都府京都市北区小松原北町 58) In this study, we propose a method to consider deformability of elements for a failure analysis of masonry structures using the DEM. In the original DEM, the deformability of the structure can be modeled by overlapping between rigid elements, but Poisson's effect cannot be modeled. In the proposed method, an element is divided into two parts, an inner part to consider deformation of the element itself, and an outer part to deal with contact between elements. The stiffness of the inner part is modeled using the stiffness matrix of the finite element method. When two elements are continuous or in contact, springs are set between the elements and the spring constants are estimated based on the original DEM and the length of the outer part. The validity of the method is confirmed through the comparison of elastic deformation with the FEM. It is found that the original DEM and the proposed method show different failure patterns, and considering the deformability of element is found to be necessary.
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 2014
Regarding 2011 Tohoku Earthquake and Tsunami, more than 20,000 people were killed or missing. In ... more Regarding 2011 Tohoku Earthquake and Tsunami, more than 20,000 people were killed or missing. In addition, more than 90% of killed people were due to tsunami. Many people could not or did not evacuate from tsunami despite enough evacuation time and warning information. The awareness of danger in a community increases by not only information given by the governments and the mass media but also behaviors of people in a community. After their awareness reaches their upper limit, they start evacuation. In this study, authors developed the simulation model for the initiation process of community's tsunami evacuation focusing on awareness of danger in a community. Authors verified the model with simple conditions, and validated in the case study of an elderly care facility which was attacked by the 2011 Tohoku tsunami.
Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 2013
Fundamental study on a simple evaluation method of seismic safety of road embankment structures 古... more Fundamental study on a simple evaluation method of seismic safety of road embankment structures 古川愛子*，水上輝**，清野純史*** Aiko FURUKAWA, Akira MIZUKAMI and Junji KIYONO *博(工) 京都大学大学院 地球環境学堂 准教授(〒615-8540 京都市西京区京都大学桂) **京都大学大学院 地球環境学舎 修士課程(〒615-8540 京都市西京区京都大学桂) ***博(工) 京都大学大学院 地球環境学堂 教授(〒615-8540 京都市西京区京都大学桂) This study proposes a simple evaluation method of seismic safety of road embankments. The safety of the embankments is confirmed by comparing the analyzed sliding displacement with the allowable displacement. The method is simple, but it has the equivalent accuracy with the Newmark method. The proposed method consists of two-step evaluations. In the first step, the method uses the equivalent yield acceleration, which is the PGA of ground motion whose sliding displacement reaches the allowable displacement. The method extracts the embankments which have the possibility to slide longer than the allowable displacement. In the second step, the method easily calculates the sliding displacement assuming the planar sliding surface for all embankments extracted in the first step. The validity of the method was confirmed by the numerical simulation.
The Great East Japan Earthquake exerted serious damage over an unprecedentedly wide range. The ea... more The Great East Japan Earthquake exerted serious damage over an unprecedentedly wide range. The earthquake prevented the supply of materials indispensable to restoration and revival in its aftermath, including fuels such as gasoline. In this study, we apply a system dynamics solution to investigate the causes and bottlenecks of this problem in order to ameliorate similar problems in wide-ranging disasters that are expected to occur, such as the Huge Nankai Trough Quake.
Uploads
Papers by Junji Kiyono