Link Slab Capacity In Bridges Supported By Lead Rubber Bearing And Elastomer

Debris accumulation in bridge slab gaps which use expansion joints can restrain deck expansion, causing undesirable forces on floor deck and damage to the structure. In order to avoid the worst possibility that can occur, an alternative using link slab is utilized. The use of link slab at high level seismic force location, requires the Seismic Isolation System on bridge to reduce the seismic force. The application of Seismic Isolation System can be conducted by Lead Rubber Bearing (LRB) type of seismic isolator. This study compares the use of Lead Rubber Bearing (LRB) and elastomer on bridge link slabs against the dimension of the link slab. In this study structural modeling used 2 models: bridges supported by elastomer and bridges supported by LRB with software-made. The link slab analysis approach used were analytical methods or classical methods. Based on results of the analysis, the width of the crack that occured on bridge supported by LRB is 0.218 mm while on the bridge supported by elastomer is 0.269 mm. The use of Lead Rubber Bearing (LRB) type of support will give more advantages to the design of the link slab since it results in smaller crack design criteria.

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A study on seismic isolation of building used LRB

Challenge Journal of Structural Mechanics ◽

10.20528/cjsmec.2020.02.001 ◽

2020 ◽

Vol 6 (2) ◽

pp. 52

Author(s):

Muhammet Yurdakul ◽

Mehmet Burak Yıldız

Keyword(s):

Seismic Isolation ◽

Base Isolation ◽

Dynamic Loads ◽

Isolation System ◽

Rubber Bearing ◽

Lead Rubber Bearing ◽

Earthquake Design ◽

Base Isolation System ◽

Internal Forces ◽

Storey Building

Base isolation system with lead rubber bearing (LRB) is commonly used to prevent structure against to damage of earthquake. Design of LRB system is detailed in this study. The isolated building with LRB design according to Uniform Building Code (UBC-97) and fixed building were examined. The six-storey building with LRB and fixed building were modelled in SAP2000 with the same dynamic loads. The relative floor displacement and internal forces of the seismic isolated and fixed building are compared. In addition, transverse and longitudinal reinforcement of any axis of seismic isolated and fixed building are compared. Analyse results showed that effectiveness of using seismic isolation system on building. The weight of longitudinal and transverse reinforcement of isolated building is smaller than fixed building about 36%, 40% respectively.

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Study on a New Seismic Isolation System Based on Dynamic Test

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.638-640.1873 ◽

2014 ◽

Vol 638-640 ◽

pp. 1873-1879

Author(s):

Wen Xia Yang ◽

Tian Qi Song ◽

Rong Jin Shi

Keyword(s):

Seismic Isolation ◽

Dynamic Test ◽

Isolation System ◽

Seismic Isolator ◽

Seismic Force

A new seismic isolation system entirely different from wildly used Laminated Rubber seismic isolator model was suggested. Vibration table test on the Plexiglas model of the suggested seismic-isolation (S-I) system was carried out. The results show that the seismic force transferred to the superstructure is only about one-tenth of the ground vibrating.

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Comparing Rubber Bearings and Eradi-Quake System for Seismic Isolation of Bridges

Materials ◽

10.3390/ma13225247 ◽

2020 ◽

Vol 13 (22) ◽

pp. 5247

Author(s):

Chang Beck Cho ◽

Young Jin Kim ◽

Won Jong Chin ◽

Jin-Young Lee

Keyword(s):

Seismic Isolation ◽

New Technology ◽

Isolation System ◽

Seismic Safety ◽

Response Characteristics ◽

Rubber Bearing ◽

Seismic Force ◽

Isolation Systems ◽

Rubber Bearings ◽

Seismic Isolation Systems

Seismic isolation systems have been used worldwide in bridge structures to reduce vibration and avoid collapse. The seismic isolator, damper, and Shock Transmission Unit (SUT) are generally adopted in the seismic design of bridges to improve their seismic safety with economic efficiency. There are several seismic isolation systems, such as Natural Rubber Bearing (NRB), Lead Rubber Bearing (LRB), and the Eradi-Quake System (EQS). EQS as a new technology is expected to effectively reduce both seismic force and displacement, but there is still some need to verify whether it might provide an economical and practical strategy for a bridge isolation system. Moreover, it is important to guarantee consistent performance of the isolators by quality control. A comparative evaluation of the basic properties of the available seismic isolators is thus necessary to achieve a balance between cost-effectiveness and the desired performance of the bridge subjected to extreme loading. Accordingly, in this study, the seismic response characteristics of the seismic isolation systems for bridges were investigated by conducting compressive test and compressive-shear test on NRB, LRB, and EQS.

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Development on Rubber Bearings for Sodium-Cooled Fast Reactor: Part 2 — Fundamental Characteristics of Half-Scale Rubber Bearings Based on Static Test

Volume 8: Seismic Engineering ◽

10.1115/pvp2015-45263 ◽

2015 ◽

Cited By ~ 2

Author(s):

Tsuyoshi Fukasawa ◽

Shigeki Okamura ◽

Tomohiko Yamamoto ◽

Nobuchika Kawasaki ◽

Takahiro Somaki ◽

...

Keyword(s):

Fast Reactor ◽

Static Loading ◽

Seismic Isolation ◽

Linear Strain ◽

Isolation System ◽

Rubber Bearing ◽

Strain Limit ◽

Seismic Force ◽

Loading Tests ◽

Rubber Bearings

This paper described the results of the static loading tests using a half-scale thick rubber bearing to investigate the fundamental characteristics such as horizontal and vertical restoring force of a rubber bearing applied to a Sodium-cooled-Fast-Reactor (SFR). Since the SFR has thin-walled component structures, a seismic isolation system is employed to mitigate the seismic force. A rubber bearing with thick rubber layers is used for the seismic isolation system applied to the SFR, it was developed aiming for isolation of not only horizontal response acceleration, but also vertical response acceleration. The thick rubber bearing of 1600 mm in diameter full-scale was designed to provide about a 10000 kN rated load with a horizontal natural period of 3.4 s and a vertical one of 0.125 s. Moreover, a linear strain limit of the thick rubber bearing was designed to accept a horizontal displacement of 700 mm or more in order to ensure a double safety margin for response displacements against a design basis ground motion. The static loading tests were performed using a half-scale thick rubber bearing with a diameter of 800 mm to investigate the horizontal/vertical stiffness, damping ratio, a linear strain limit in horizontal direction and a tensile yield stress in the vertical direction. The fundamental characteristic of rubber bearings employed to the SFR and the validity of a design formula became clear through the static loading tests.

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Seismic performance of Greater Jakarta LRT with added lead rubber bearing using non-linear time history analysis

IABSE Congress, Christchurch 2021: Resilient technologies for sustainable infrastructure ◽

10.2749/christchurch.2021.0487 ◽

2021 ◽

Author(s):

Iswandi Imran ◽

Marie Hamidah ◽

Tri Suryadi ◽

Hasan Al-Harris ◽

Syamsul Hidayat

Keyword(s):

Linear Time ◽

Time History ◽

Time History Analysis ◽

Performance Level ◽

Structural Performance ◽

Isolation System ◽

Rubber Bearing ◽

Lead Rubber Bearing ◽

History Analysis ◽

Seismic System

<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>

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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.

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Shaking Table Test Study on Mid-Story Isolation Structures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.378 ◽

2012 ◽

Vol 446-449 ◽

pp. 378-381

Author(s):

Jian Min Jin ◽

Ping Tan ◽

Fu Lin Zhou ◽

Yu Hong Ma ◽

Chao Yong Shen

Keyword(s):

Seismic Response ◽

Seismic Isolation ◽

Shaking Table Test ◽

Base Isolation ◽

Shaking Table ◽

Natural Period ◽

Isolation System ◽

Isolation Layer ◽

Lead Rubber Bearing ◽

Complex Structural

Mid-story isolation structure is developing from base isolation structures. As a complex structural system, the work mechanism of base isolation structure is not entirely appropriate for mid-story isolation structure, and the prolonging of structural natural period may not be able to decrease the seismic response of substructure and superstructure simultaneously. In this paper, for a four-story steel frame model, whose prototype first natural period is about 1s without seismic isolation design, the seismic responses and isolation effectiveness of mid-story isolation system with lead rubber bearing are studied experimentally by changing the location of isolation layer. Respectively, the locations of isolation layer are set at bottom of the first story, top of the first story, top of the second story and top of the third story. The results show that mid-story isolation can reduce seismic response in general, and substructure acceleration may be amplified.

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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.

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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>

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