Elastic properties of civil engineering structures change when subjected to a dynamic excitation. The modal frequencies show rapid decrease followed by relaxation, or slow recovery, that is dependent on the level damage. In this article, we analyze recovery process applying three relaxation models fit real earthquake data recorded in Japanese building shows variant structural state over 20 years. Despite differences conditions, different scales and complexity real-scale problem, originally...

The 11 March 2011 M 9.0 Tohoku earthquake generated long-duration shaking that propagated hundreds of kilometers from the epicenter and affected tall buildings in urban areas several hundred main shock. Recorded responses show were by long-period motions. This study presents behavior performance a 37-story building Tsukuda area Tokyo, Japan, as inferred modal analyses records retrieved for time interval covering few days before, during, months after U.S. “code-type” array comprises three...

The Building Research Institute (BRI) of Japan operates a strong motion network that covers buildings in major cities across Japan. A great number data has been accumulated the observing stations integrated over many years. This paper selects four high-rise steel-framed from BRI network. These suffered severe shakings 2011 Tohoku Earthquake. To discuss dynamic characteristics buildings, fundamental natural periods and damping ratios target are identified using data. First, changes with time...

A sparsely instrumented 55-story building in Osaka, Japan, had recorded unprecedented, severe, and long-duration, long-period resonating responses during the 11 March 2011 M9.0 Tohoku earthquake that occurred at 767 km distance. Thereafter, studies of records resulted implementation a significant retrofit design, comprising dampers buckling restrained braces (BRBs). The retrofitted were also 24 April 2016 M7.3 Kumamoto 478 km. on-demand acquired ambient response data are analyzed this study...

During the 2011 Tohoku-oki earthquake, a large number of response records from various types buildings were obtained. The give us actual motions during exceptionally earthquakes that are considered comparable with design earthquakes. Various earthquake have been collected, and their properties several will exhibit implications for structural discussed.

Since it is well known that the vibration characteristics such as eigenperiod and damping ratio of buildings are dependent on amplitude vibration. In this paper, these horizontal first mode, based seismic observation records obtained from low middle raised RC SRC buildings, studied. These evaluated corresponding to 2 levels, small earthquake level level. The data analyzed using ARX model. effects experience large earthquakes aging for each investigated.

Change in dynamic characteristics of ten super high-rise buildings during the 2011 Great East Japan Earthquake was investigated through analyses strong motion data.The natural periods two RC obviously increased earthquake, and were not recovered after shaking. On other hand, change eight steel extremely small.Amplitude dependency examined. The to response amplitudes clearly recognized trends different between before earthquake.

Understanding of dynamic characteristics building structures is a key issue in the seismic design technology. From this point view, Building Research Institute (BRI) operating strong motion network for buildings since 1957. The BRI annex one stations and densely instrumented with 22 accelerometers. In paper, variation discussed using records. Decreasing fundamental natural frequencies passage time recognized from optimizing analysis 158 records single-degree-of-freedom system. 16 relatively...

Abstract This study focuses on the first‐modal natural periods and damping ratios of buildings in vertical direction. An auto regression exogenous (ARX) model is used to identify each period ratio. The targets comprise over 3,000 earthquake observation records for 18 comprising reinforced concrete, steel structures. identified values are summarized structural type, their characteristics discussed view input amplitude height buildings, compared ratio horizontal Based results, a simple...

A seismic performance curve shows the relationship between representative displacement (Sd) and equivalent base shear force coefficient (Sa) of a structure. The capacity building can be assessed in straightforward manner using simple Sa-Sd skeleton curve. In this study, earthquake response records were used to obtain Sa-Sdcurves for steel-reinforced concrete (SRC) assess changes that occur during an earthquake. This paper compares curves 8-story SRC 27 strong earthquakes occurred Japan 1998...

In this study, we identified superstructure stiffness and sway/rocking using seismic observation data for an eight-story steel-encased reinforced concrete building which continuous had been made since the completion of construction. We analyzed structural aging amplitude dependence stiffness. The target is Research Center Disaster Risk Management National Institute Land Infrastructure (completed in March 1998). Accelerometers on nearby surface ground, first basement level, floor, second...

Dynamic characteristics of buildings are key issues in the seismic design technology. From this point view, Building Research Institute is operating strong motion network for since 1957. In paper, dynamic actual estimated using acceleration records BRI network. For an instance, transition natural periods and damping ratios slightly damaged by earthquake examined moving time window technique. The change depending on displacement amplitude can be verified. Relation among periods, building...

Dynamic properties of 23 middle-low rise RC/SRC buildings during the 2011 off pacific coast Tohoku earthquake was investigated through identification strong motion data.From result SDOF simulated wave, identified results data can be reproduced. Viscous damping estimated from part small amplitude. The change natural periods is related to damage condition buildings.

建築研究所は免震構造を採用した釧路合同庁舎を対象に, その竣工時から強震観測を実施している。2000年の観測開始以来5年間に, 2003年十勝沖地震を始めとして, 多くの貴重な強震記録を得ることができた。本論文は, 釧路合同庁舎で得られた強震記録の分析から, 免震建物の振動特性を検討している。十勝沖地震で得られた強震記録の分析からは, 表層地盤や免震層の非線形挙動が確認された。また, 多質点系せん断モデルを用いた非線形応答解析結果から, 合同庁舎に設置された免震装置は, 設計時に想定した免震性能を発揮したことが確認された。過去に得られた89地震の強震記録から推定した上部構造の振動特性からは, 最大振幅の増加に伴って固有振動数が低下する, 剛性の振幅依存性が確認された。また, 十勝沖地震の前後では固有振動数に違いが見られ, 大きな地震を経験することによる振動特性の変化が認められた。免震層を加えた2質点系のモデルを用いた剛性と減衰定数の推定結果は, 免震層の変位が2cmを超えるような大きな振幅の記録では, 理論的な等価剛性や等価減衰定数と良い対応を示した。通常,...

Building Research Institute (BRI) is operating a nationwide strong motion network. Total 75 stations are disposed in major cities throughout Japan. The observation project aims to contribute advance seismic design technology for buildings. Therefore response of buildings the main target observation. A great number records have been obtained and utilized study local site geological effects, soil-structure interaction dynamic behavior paper introduces outline BRI network its recent topics.

Nonlinear elasticity has been observed in different materials and at scales (from laboratory tests to the crust of Earth). This behavior is evidenced by nonlinear response accompanied slow dynamics, a process which elastic properties recover (fully or partially) values previous excitation. In this study we show that also occurs buildings scale, where signatures can be even for low levels strain, dynamics seen both short long-term monitoring. Although physics behind remains unknown, it...

Since it is well known that the vibration characteristics such as natural period and damping ratio of buildings are dependent on shaking amplitude building. In previous paper, these horizontal 1st mode for low middle raised RC SRC were studied. this those 2nd 8 high rised steel The observed seismic data including 2011 off Pacific Coast Tohoku Earthquake (hereafter, 3.11 earthquake) analyzed using ARX (Auto-Regressive eXogenous) model. results estimated 2 averaged drift angle levels (the...

The method for evaluation of the building structure response reduction by soil interaction (SSI) from seismographs soil-structure system is presented.In proposed method, simplified SSI model employed, and parameter determined identification.In identification, both inertial (II) kinematic (KI) are considered.It also presented to indicate II KI respectively.The procedures applied observed records 2011 off Pacific coast Tohoku Earthquake.It clarified that effect decreased when super enters...