RECOVERY OF LOAD-BEARING PERFORMANCE FOR A CONTINUOUS STEEL PLATE GIRDER BRIDGE DAMAGED BY THE 2016 KUMAMOTO EARTHQUAKE AND CONSIDERATION FOR ITS DESIGN

2021 ◽  
Vol 77 (2) ◽  
pp. 304-318
Author(s):  
Fumi MIYAHARA ◽  
Takahiro IMAMURA ◽  
Hideaki NISHIDA ◽  
Jun-ichi HOSHIKUMA
Keyword(s):  
Steel Plate ◽  
Continuous Steel ◽  
2016 Kumamoto Earthquake ◽  
Load Bearing ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Girder Bridge ◽  
Plate Girder

scholarly journals An Investigation of Damage Mechanism Induced by Earthquake in a Plate Girder Bridge Based on Seismic Response Analysis: Case Study of Tawarayama Bridge under the 2016 Kumamoto Earthquake

2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Mya Nan Aye ◽  
Akira Kasai ◽  
Mitsuhiro Shigeishi
Keyword(s):  
Dynamic Response ◽  
Seismic Response ◽  
Damage Mechanism ◽  
Response Analysis ◽  
2016 Kumamoto Earthquake ◽  
Seismic Response Analysis ◽  
Damage Survey ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Girder Bridge

This paper reports a damage survey and seismic analysis of a bridge. In the first part, the damage survey of some bridges that were affected by the 2016 Kumamoto Earthquake was discussed. Among these bridges, the Tawarayama Bridge, which is a plate girder bridge located very close to an active fault line, was particularly considered. This bridge incurred severe damage because of the earthquakes’ epicenters very close to the bridge. The damage mechanism that can occur in this type of bridge was elucidated. During the damage survey, parts of Tawarayama Bridge were examined to determine the damage in order to examine the factors of occurrence and damage mechanism. In the second part, the seismic responses of Tawarayama Bridge were analyzed using ABAQUS software, and beam elements were applied for the structural members. Firstly, the time-history responses were analyzed using both longitudinal and transverse direction earthquake ground motions separately and simultaneously to investigate the dynamic response of the bridge. Both undamped and damped conditions were considered. For the dynamic response analysis, the recorded earthquake acceleration data of Ozu Station were applied for both undamped and damped conditions considering both east-west (EW) and north-south (NS) directions simultaneously and the damped condition for these directions separately. In addition, a damped model was analyzed by applying design earthquake input data obtained from the Japanese Seismic Design Specifications for Highway Bridges. Consequently, five cases were established for seismic response analysis. Subsequently, the seismic responses of Tawarayama Bridge were investigated, and the behavior of the lower lateral members was examined considering the observed buckling of these members during the damage survey. The field survey and dynamic response analysis indicate that the buckling design of the lower lateral members should be considered in the future design of bridges.

scholarly journals Seismic velocity structure at the southern termination of the 2016 Kumamoto Earthquake rupture, Japan

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Yasuhira Aoyagi ◽  
Haruo Kimura ◽  
Kazuo Mizoguchi
Keyword(s):  
Fault Zone ◽  
Velocity Structure ◽  
Seismic Velocity ◽  
Earthquake Rupture ◽  
2016 Kumamoto Earthquake ◽  
Seismic Velocity Structure ◽  
Kumamoto Earthquake ◽  
Seismogenic Layer ◽  
The 2016 Kumamoto Earthquake ◽  
Tectonic Line

Abstract The earthquake rupture termination mechanism and size of the ruptured area are crucial parameters for earthquake magnitude estimations and seismic hazard assessments. The 2016 Mw 7.0 Kumamoto Earthquake, central Kyushu, Japan, ruptured a 34-km-long area along previously recognized active faults, eastern part of the Futagawa fault zone and northernmost part of the Hinagu fault zone. Many researchers have suggested that a magma chamber under Aso Volcano terminated the eastward rupture. However, the termination mechanism of the southward rupture has remained unclear. Here, we conduct a local seismic tomographic inversion using a dense temporary seismic network to detail the seismic velocity structure around the southern termination of the rupture. The compressional-wave velocity (Vp) results and compressional- to shear-wave velocity (Vp/Vs) structure indicate several E–W- and ENE–WSW-trending zonal anomalies in the upper to middle crust. These zonal anomalies may reflect regional geological structures that follow the same trends as the Oita–Kumamoto Tectonic Line and Usuki–Yatsushiro Tectonic Line. While the 2016 Kumamoto Earthquake rupture mainly propagated through a low-Vp/Vs area (1.62–1.74) along the Hinagu fault zone, the southern termination of the earthquake at the focal depth of the mainshock is adjacent to a 3-km-diameter high-Vp/Vs body. There is a rapid 5-km step in the depth of the seismogenic layer across the E–W-trending velocity boundary between the low- and high-Vp/Vs areas that corresponds well with the Rokkoku Tectonic Line; this geological boundary is the likely cause of the dislocation of the seismogenic layer because it is intruded by serpentinite veins. A possible factor in the southern rupture termination of the 2016 Kumamoto Earthquake is the existence of a high-Vp/Vs body in the direction of southern rupture propagation. The provided details of this inhomogeneous barrier, which are inferred from the seismic velocity structures, may improve future seismic hazard assessments for a complex fault system composed of multiple segments.

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