Hybrid Control of a Benchmark Cable-Stayed Bridge Considering Nonlinearity of a Lead Rubber Bearing

<p>In order to overcome stringent seismic requirement in the new Greater Jakarta Light Rail Transit Project, a breakthrough seismic system shall be chosen to obtain expected structural performance. This seismic system shall be designed to provide operational performance level after strong earthquake events. To achieve the criteria, seismic isolation system using Lead Rubber Bearings is chosen. With this isolation system, Greater Jakarta LRT has become the first seismically isolated infrastructure and apparently an infrastructure with the largest numbers of LRBs in one single project in Indonesia. More than 10.400 Pcs LRBs are used for the first phase of the construction and the numbers will be certainly increased in the next phase of the construction. To evaluate the structural performance, non-linear time history analysis is used. A total of 3 pair matched ground motions will be used as the input for the response history analysis. The ability of the lead rubber bearing to isolate and dissipate earthquake actions will determine its structural performance level. This will be represented by the nonlinear hysteretic curves obtained throughout the earthquake actions.</p>

Download Full-text

A comparative study of base isolation devices in light rail transit structure featured with lead rubber bearing and friction pendulum system

MATEC Web of Conferences ◽

10.1051/matecconf/201819502013 ◽

2018 ◽

Vol 195 ◽

pp. 02013

Author(s):

Santi Nuraini ◽

Asdam Tambusay ◽

Priyo Suprobo

Keyword(s):

Seismic Isolation ◽

Time History ◽

Light Rail ◽

Rail Transit ◽

Light Rail Transit ◽

Pendulum System ◽

Rubber Bearing ◽

Lead Rubber Bearing ◽

Friction Pendulum ◽

Friction Pendulum System

Advanced nonlinear analysis in light rail transit (LRT) structures has been undertaken to examine the influence of seismic isolation devices for reducing seismic demand. The study employed the use of two types of commercially available bearings, namely lead rubber bearing (LRB) and friction pendulum system (FPS). Six LRT structures, designed to be built in Surabaya, were modelled using computer-aided software SAP2000, where each of the three structures consisted of three types of LRB and FPS placed onto the pier cap to support the horizontal upper-structural member. Nonlinear static pushover and dynamic time history analysis with seven improved ground motion data was performed to gain improved insights on the behavioural response of LRT structures, allowing one to fully understand the supremacy of seismic isolations for protecting the structure against seismic actions. It is shown that both devices manage to isolate seismic forces, resulting in alleviation of excessive base shear occurring at the column. In addition, it is noticeable that the overall responses of LRB and FPS shows marginal discrepancies, suggesting both devices are interchangeable to be used for LRT-like structures.

Download Full-text

Respuesta Sísmica de Tanques de Concreto Armado para Almacenamiento de Agua con Sistema de Aislación del Tipo Elastomérico con Núcleo de Plomo

Revista Sul-americana de Engenharia Estrutural ◽

10.5335/rsaee.v16i2.6570 ◽

2019 ◽

Vol 16 (2) ◽

Author(s):

Elvis Jony Mamani

Keyword(s):

Rubber Bearing ◽

Lead Rubber Bearing ◽

El Sistema

Se muestran las respuestas sísmicas de tanques de Concreto Armado (CA) para almacenamiento de agua con sistema de aislación del tipo Elastomérico con Núcleo de Plomo (lead rubber bearing, LRB) bajo solicitación sísmica bi-direccional. Para el análisis sísmico se consideró que el tanque posee comportamiento lineal elástico, además se empleó un modelo mecánico equivalente para representar la interacción tanque-agua, y se utilizó un modelo histerético del tipo bi-axial para representar el comportamiento del sistema de aislación. Los parámetros de estudio son: la razón altura de agua-radio interior del tanque, la razón espesor de la pared del tanque-radio interior del tanque, el periodo de vibración objetivo del sistema de aislación, y la razón de resistencia del sistema de aislación. Se utilizaron 21 pares de registros sísmicos del movimiento del suelo. Las respuestas sísmicas del sistema de base aislada muestran una efectividad en la reducción de los valores de la fuerza cortante basal en comparación con el sistema de base fija del orden de 17% a 74% para H/R = 0.5; de 50% a 83% para H/R = 1.0; de 75% a 91% para H/R = 2.0 (H/R = razón altura de agua-radio interior del tanque).

Download Full-text

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 6 — Scaled Tests to Obtain Basic Characteristics of Lead Rubber Bearing

Volume 8: Seismic Engineering ◽

10.1115/pvp2014-29002 ◽

2014 ◽

Author(s):

Tsutomu Hirotani ◽

Ryota Takahama ◽

Masaki Yukawa ◽

Hiroshi Hibino ◽

Yuji Aikawa ◽

...

Keyword(s):

Nuclear Power ◽

Seismic Isolation ◽

Evaluation Method ◽

Loading Test ◽

Rubber Bearing ◽

Lead Rubber Bearing ◽

Basic Characteristics ◽

Isolation Systems ◽

Seismic Isolation Systems ◽

Hysteresis Characteristics

This paper provides a series comprising the “Development of Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”. Part 6 presents scaled tests for Lead Rubber Bearing (LRB) newly developed for this project. Following tests are performed to obtain the basic characteristics of LRB,. (1) Horizontal and Vertical Simultaneous Loading Test: LRBs with diameter of 250mm are tested dynamically under simultaneous axial and lateral loading. The hysteresis characteristics is not changed under compressive load although it is changed under tensile load. (2) Basic Break Test: LRBs with a diameter of 800mm are tested statically under various combinations of axial and lateral forces. The hysteresis characteristics model of LRB is determined by this test. It is confirmed that the breaking strain of LRB under compression load exceeds 450%. (3) Horizontal Hardening and Vertical Softening Test: For LRBs with a diameter of 1200 mm, 75% scale of actual LRB are tested statically for horizontal hardening and vertical softening regions. It is confirmed that the hysteresis model which is developed by smaller LRBs is applicable to these large scale models.

Download Full-text

Improving the Seismic Behavior of Symmetrical Steel Structures Under Near-Field Earthquake Using a Base Isolation Method Lead Rubber Bearing Isolator

Modern Applied Science ◽

10.5539/mas.v10n7p10 ◽

2016 ◽

Vol 10 (7) ◽

pp. 10

Author(s):

Musa Mazji Till Abadi ◽

Behnam Adhami

Keyword(s):

Seismic Isolation ◽

Retaining Wall ◽

Vertical Component ◽

Steel Structures ◽

Vertical Movements ◽

Near Fault ◽

Rubber Bearing ◽

Lead Rubber Bearing ◽

Fixed Base ◽

Near Fault Earthquakes

<p>In this study, the function and application of seismic isolation system through lead rubber bearing isolator (LRB) in near-fault earthquakes are compared with fixed-base structures. As a result of their high frequency content, near-fault earthquakes impose huge energy on structures and cause severe damages. One of the appropriate solutions for this issue is the use of LRB which decreases the amount of imposed energy on structures. To improve the function of isolated structures under the near-fault earthquakes, isolators are designed in a way to tolerate the vertical component of earthquakes. To this purpose, we limit the displacements due to the horizontal movements of isolator through Gap spring which acts as a retaining wall and prevent shocks to other buildings. Moreover, this approach decreases the vertical movements of isolators and indirectly improves their behavior. In the current study, three buildings with four, eight, and 12 floors (with and without gap spring) were included. Isolators were manually designed in accordance with AASHTO-LRB regulations and the behaviors of both isolators and buildings are considered non-linear. Then we analyzed and compared the amount of energy, displacement, and acceleration of structure at the center of roof. The results indicated a significant decrease in the results of base shear, the acceleration of roof center, floors drift and energy imposed on the structure in the isolated system in comparison with the fixed-base structure.</p>

Download Full-text