Effects and dynamic characteristics of the core‐suspended isolation system assessed by long‐term structural health monitoring

Abstract

The seismic isolation mechanism of the core‐suspended isolation (CSI) system comprises a double layer of inclined rubber bearings installed on top of a reinforced core structure. A multilevel structure is then suspended from a hat truss or umbrella girder constructed on the seismic isolation mechanism. The first building to use the CSI system was the Safety and Security Center in Tokyo, Japan, whose structural health monitoring system has detected and recorded 231 earthquake motions since 2006, including the 2011 Tohoku Pacific Earthquake (2011‐TPE). The present study estimates the dynamic characteristics of this CSI‐equipped building in earthquakes, and the effects of the CSI system are revealed via the observed earthquake records. The temporal changes of the fundamental period and damping factor are estimated from the 2011‐TPE; the fundamental period increases with the deformation of the isolation level, whereas the fundamental damping factor is only related weakly to that deformation. The 231 observed earthquake records reveal that the CSI system performs seismic isolation by reducing the response acceleration of the suspended structure by roughly a half for peak ground accelerations exceeding 30 cm/s2. Daily microtremor observations are used to diagnose earthquake damage; the fundamental frequencies in each direction remain almost constant and were not changed by the 2011‐TPE.

Analytical Study on the Random Seismic Responses of an Asymmetrical Suspension Structure

“…Similarly, z * i (ω) is the complex conjugate term of z i (ω) and z * i (ω) = z i (−ω). Substituting the expression of the frequency-domain solution of complex mode z i (ω), i.e., Equation (8), into Equation ( 13), the PSDF of the structural response can be expressed as:…”

“…Combined with the characteristics of suspension structures, the structural vibration was reduced with the arrangement of rocking walls and connection damping. A novel CSI vibration isolation system, made of double-layer inclined rubber bearings and installed on top of the core frame, was also proposed by Saruta et al [7], and its good seismic performance was confirmed by shaking table tests and long-term structural health monitoring [8]. The seismic responses of suspension buildings with viscous dampers under 20 ground motion time-history curves were analyzed in previous research [9], and the results indicated that the structural response was affected by the arrangement of dampers and the inter-layer stiffness.…”

Salud estructural en edificaciones utilizando tecnología BIM: Revisión literaria

“…El monitoreo de salud estructural (SHM) es un sistema que puede monitorear el movimiento estructural de un edificio durante cargas externas como terremotos (Ren, 2020). Las vibraciones del sistema de aislamiento sísmico de núcleo suspendido (CSI) se utiliza para la seguridad y protección del edificio, cuyo sistema de vigilancia de la salud estructural (SHM) detecta y registra movimiento sísmico (Nakamura & Okada, 2021). La vida eficaz de los edificios convencionales a gran escala por lo regular se decreta en cientos de años, mientras que la vida útil de los propios sensores del sistema de monitoreo de salud estructural (SHM) solo se puede mantener en más de diez años o incluso menos, lo cual es muy importante y significativo que se identifique, detecte de manera oportuna y efectiva las fallas de los sensores en el sistema SHM del edificio .…”

High accuracy and resolution damage detection for concrete based on novel virtual correlation imaging method and embedded piezoelectric sensing technology

“…NDE and SHM techniques, thereby preventing catastrophic structural failure. In the past decades, various NDE and SHM approaches have been proposed and applied to civil engineering structures to ensure structural safety [1][2][3][4][5].…”