scholarly journals EFFECT OF BASE ISOLATION ON MULTISTOREY STEEL STRUCTURE IN DIFFERENT SOIL CONDITIONS.

2021 ◽  
Vol 10 (3) ◽  
pp. 38-46
Keyword(s):  
Base Isolation ◽  
Steel Structure ◽  
Soil Condition ◽  
Soil Conditions ◽  
Building Structures ◽  
Lead Rubber Bearings ◽  
Predetermined Level ◽  
Leading Position ◽  
Potential Damage ◽  
Rubber Bearings

A quake is a random tremor or movement of the earth’s crust, which is developed naturally on or below the surface of earth. While designing a structures in seismically active area, a designer has to make provision of predetermined level of reliability and earthquake resistance of building structures. Now, to improve the seismic resistance, various isolation techniques, including lead rubber bearings, which occupy a leading position in the construction practice utilization, are being increasingly applied. Base isolation (BI) system for buildings is introduced to separate the building structure from potential damage induced by earthquake motion, preventing the building superstructures from absorbing the earthquake energy. A study determining the effectiveness of base isolators is carried out on multi-storey structures with varying height and in different soil condition.

Analysis and Experiment on the Effect of Seismic Protection of Buildings by High Damping Rubber Bearings

2004 ◽  
Author(s):  
Jun-Ping Pu ◽  
C. S. Tsai ◽  
Jian-Fa Huang ◽  
Bo-Jen Chen ◽  
Yao-Min Fang
Keyword(s):  
Earthquake Engineering ◽  
Base Isolation ◽  
Steel Structure ◽  
Shaking Table ◽  
Natural Period ◽  
Rubber Bearing ◽  
High Damping Rubber Bearings ◽  
High Damping Rubber Bearing ◽  
High Damping Rubber ◽  
Rubber Bearings

In recent years, many studies on base isolation strategies and devices have been developed and applied in U. S. A., Europe, Japan, and New Zealand. The high damping rubber bearing belongs to one kind of the earthquake-proof ideas of base isolation technologies. The installation of high damping rubber bearings can lengthen the natural period of a building and simultaneously reduce the earthquake-induced energy trying to impart to the building. The objective of this paper is to investigate the base isolation effect of high damping rubber bearings. The uniaxial, biaxial, and triaxial shaking table tests were performed to study the seismic behavior of a 0.4-scale three-story isolated steel structure in the National Center for Research on Earthquake Engineering in Taiwan. The experimental and analytical results show that the nonlinear mechanical characteristics of the high damping rubber bearings can be reasonably simulated.

Some Retrofit Options for the Seismic Upgrading of Old Low-Rise School Buildings in Mexico

1996 ◽  
Vol 12 (4) ◽  
pp. 883-902 ◽  
Author(s):  
Arturo Tena-Colunga
Keyword(s):  
Mexico City ◽  
Pacific Coast ◽  
Longitudinal Direction ◽  
Soil Conditions ◽  
School Buildings ◽  
Mexican Pacific ◽  
Acceleration Time Histories ◽  
Lead Rubber Bearings ◽  
Time Histories ◽  
Rubber Bearings

An analytical study regarding the seismic upgrading of typical 60's and 70's designs for public school buildings in Mexico is presented. Some schools with these designs were moderately damaged during the 1985 Michoacán Earthquake in Mexico City. The damage was primarily observed in their longitudinal direction where existing slender RC columns have their weak axis. In addition, these columns are confined and shortened by masonry walls that do not run all the story height. These walls are supposed to be non-structural components, however, they experienced shear cracking during the quake due to the distress of the confined columns. Some school buildings were retrofitted after the Michoacán Earthquake adding post-tensioned bracing systems composed of prestressed high-slenderness steel strands (tension-only bracing systems), a retrofit option that is economical. In fact, there is an interest on assessing the effectiveness of this retrofit scheme in other regions with different soil conditions, as for example, the hard soils of the Mexican Pacific Coast. Therefore, the post-tensioning retrofit scheme used for the school buildings in Mexico City was also evaluated for hypothetical locations in the Mexican Pacific Coast. Another option that seems economical for the seismic retrofit of old school buildings in the Mexican Pacific Coast is the use of base isolators. Then, a retrofit plan using lead-rubber bearings was also evaluated. Acceleration time-histories recorded in the Mexican Pacific Coast during the 1985 Michoacán and the 1995 Manzanillo Earthquakes were used to assess the effectiveness of the studied retrofit schemes. Records in Mexico City for the 1985 Michoacán Earthquake and postulated ground motions for a Ms = 8.1 earthquake in Mexico City were also used. The effectiveness of each retrofit scheme is discussed through the comparison of the seismic behavior of original and retrofit structures using a comprehensive set of analyses.

Experimental Study of a Multiple Bay Structure Isolated With Hybrid Bearings

2003 ◽  
Author(s):  
C. S. Tsai ◽  
Bo-Jen Chen ◽  
Tsu-Cheng Chiang ◽  
Guan-Hsing Lee
Keyword(s):  
Earthquake Engineering ◽  
Base Isolation ◽  
Steel Structure ◽  
Seismic Energy ◽  
Shaking Table ◽  
Element Formulation ◽  
Shaking Table Tests ◽  
Seismic Responses ◽  
Promising Tool ◽  
Rubber Bearings

In conventional earthquake resistance design approach (the ductility-design philosophy), the energy dissipation mechanism is based on plastic deformations at scattered locations in the structure. However, this can produce permanent damage to the joints as well as the larger interstory displacements. In recently years, the base isolation technology has been adopted as a feasible and attractive way in improving seismic resistance of structures. It can shift the natural periods of structures away from the rich periods contents of earthquake motions, but also provide considerable supplemental damping to dissipate seismic energy transmitted into structures during earthquakes. In this paper, uniaxial, biaxial, and triaxial shaking table tests are performed to study the seismic behavior of a 0.4-scale three-story isolated steel structure in the National Center for Research on Earthquake Engineering in Taiwan. Experimental results demonstrate that structures with hybrid rubber bearings can actually decrease the seismic responses of the superstructure. It has been proved through the shaking table tests that the rubber bearing is a very promising tool to enhance the seismic resistibility of structures. Moreover, it is illustrated that the proposed analytical model and finite element formulation in this paper can well predict the mechanical behavior of rubber bearings and seismic responses of the base-isolated structures.

scholarly journals Fixed and Base Isolated Framed Structures: A Comparative Study

2021 ◽  
Vol 2070 (1) ◽  
pp. 012198
Author(s):  
Sajan K Jose ◽  
G S Anjali ◽  
Aarya S Nair ◽  
D A Adithya ◽  
Ananya Sony ◽  
...  
Keyword(s):  
Composite Structures ◽  
Base Isolation ◽  
Response Spectrum ◽  
Structural Vibration ◽  
Structural Vibration Control ◽  
Rc Structure ◽  
Lead Rubber Bearings ◽  
Different Shapes ◽  
Control Technologies ◽  
Rubber Bearings

Abstract Necessity of constructing multi-storied buildings is increasing these days. But they are more prone to severe damage due to earthquakes. Base isolation is one of the most powerful tools pertaining to the passive structural vibration control technologies. The structure above the ground, is separated from the effects of earthquake forces by introducing a mechanism that helps the structure to hover. This project deals with analysis of 10 storey RCC, Steel and Composite structures of different shapes with and without base isolation in various seismic zones by Response Spectrum Method using ETABS software. Lead rubber bearings designed as per UBC97 was used for base isolation. Plus shape was found to be most suitable for base isolation for RC structure, whereas for steel and composite structures rectangular and hollow shapes were found suitable. It was also observed that concrete structure performs best when base isolated, compared to other structures.

Design of base-isolated buildings

2015 ◽  
Vol 48 (2) ◽  
pp. 118-135 ◽  
Author(s):  
Dario Pietra ◽  
Stefano Pampanin ◽  
Ron L. Mayes ◽  
Nicholas G. Wetzel ◽  
Demin Feng
Keyword(s):  
New Zealand ◽  
Base Isolation ◽  
Design Guidelines ◽  
Performance Criteria ◽  
Design Solution ◽  
Performance Requirements ◽  
Lead Rubber Bearings ◽  
Canterbury Earthquake Sequence ◽  
Pros And Cons ◽  
Rubber Bearings

Base isolation is arguably the most reliable method for providing enhanced protection of buildings against earthquake-induced actions, by virtue of a physical separation between the structure and the ground through elements/devices with controlled force capacity, significant lateral deformation capacity and (often) enhanced energy dissipation. Such a design solution has shown its effectiveness in protecting both structural and non-structural components, hence preserving their functionality even in the aftermath of a major seismic event. Despite lead rubber bearings being invented in New Zealand almost forty years ago, the Christchurch Women’s hospital was the only isolated building in Christchurch when the Canterbury earthquake sequence struck in 2010/11. Furthermore, a reference code for designing base-isolated buildings in New Zealand is still missing. The absence of a design standard or at least of a consensus on design guidelines is a potential source for a lack of uniformity in terms of performance criteria and compliance design approaches. It may also limit more widespread use of the technology in New Zealand. The present paper provides an overview of the major international codes (American, Japanese and European) for the design of base-isolated buildings. The design performance requirements, the analysis procedures, the design review process and approval/quality control of devices outlined in each code are discussed and their respective pros and cons are compared through a design application on a benchmark building in New Zealand. The results gathered from this comparison are intended to set the basis for the development of guidelines specific for the New Zealand environment.

scholarly journals Development of a Multiaction Hybrid Damper for Passive Energy Dissipation

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Ji-Eun Roh ◽  
Moo-Won Hur ◽  
Hyun-Hoon Choi ◽  
Sang-Hyun Lee
Keyword(s):  
Energy Dissipation ◽  
Steel Structure ◽  
Building Structures ◽  
Control Performance ◽  
Initial Stiffness ◽  
Earthquake Loads ◽  
Earthquake Load ◽  
Hybrid Damper ◽  
Rubber Bearings ◽  
Cyclic Loading Tests

A multiaction hybrid damper (MHD) is designed to have independent hysteretic characteristics under small and large loading conditions, and its control performance for building structures excited by wind or earthquake load is verified. The MHD is composed of steel elements, two friction pads, and two lead rubber bearings (LRBs). Because the friction pads and the LRBs are in series connection, only the LRBs deform before the friction pad slippage occurs. After the friction slippage, the damper deformation concentrates on the friction pads. The initial stiffness and hysteresis are dependent on the properties of the LRB, and the maximum force is determined by the friction pad. Accordingly, the load-deformation behaviors before/after the friction slippage can be independently designed to show optimal performance for a building structure subject to wind and earthquake loads. The cyclic loading tests of a full scale MHD were conducted to evaluate the multiaction behaviors and energy dissipation capacity of the MHD. The control performance of the MHD damper is analytically investigated by using a 20-story steel structure subject to wind loads and a 15-story RC structure excited by earthquake loads. The MHD damper showed good performance for reducing both the linear wind-induced and nonlinear earthquake-induced responses.

scholarly journals Dynamic Analyses of Isolated Structures under Bi-Directional Excitations of Near-Field Ground Motions

2012 ◽  
Vol 19 (4) ◽  
pp. 505-513 ◽  
Author(s):  
Gokhan Ozdemir ◽  
Ugurhan Akyuz
Keyword(s):  
Near Field ◽  
Soil Condition ◽  
Lateral Force ◽  
Isolation System ◽  
Wide Range ◽  
Dynamic Analyses ◽  
Lead Rubber Bearings ◽  
Rc Building ◽  
Orthogonal Components ◽  
Rubber Bearings

Nonlinear response history analyses (NRHA) of a 3-story isolated reinforced concrete (RC) building are carried out under both uni- and bi-directional earthquake excitations of near-field records. NRHA are conducted for a wide range of yield strength (Q/W) of lead rubber bearings (LRB), and isolation period (T). Selected near-field records are used to investigate both the contribution of orthogonal components on maximum isolator displacements and accuracy of equivalent lateral force (ELF) procedure on estimation of maximum isolator displacements. Analyses results show that both the contribution of orthogonal components and accuracy of ELF procedure depend on the soil condition where isolation system is implemented.

Research on the Effect of Combined Seismic Isolation System

2012 ◽  
Vol 446-449 ◽  
pp. 3299-3303
Author(s):  
Xi Sen Fan ◽  
Ting Lei Tian
Keyword(s):  
Seismic Response ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Seismic Responses ◽  
Combined System ◽  
Isolation System ◽  
Lead Rubber Bearings ◽  
Base Isolation System ◽  
Rubber Bearings ◽  
The Relationship

The isolation system between the upper structure and the foundation could reduce the seismic response of the former. A system combined of sliding and lead rubber bearings (LRB) is more effective in seismic isolation than using the later alone. In this research, the seismic responses of a building which was set with LRB and a combined system (the proportions between the sliding and LRB were 1/6, 1/4 and 1/3) respectively were analyzed and compared to that of the building without base isolation system to investigate the effect of seismic isolation. The relationship between isolation coefficient and the proportion of bearings was studied. The results show that the combined system could reduce the seismic response of structure, and it is more effective in seismic isolation if the leading bearing is relatively more.

The Technique of Seismic Isolation in Story-Adding Buildings Using Light-Weight Steel Structure and its Application

2012 ◽  
Vol 174-177 ◽  
pp. 2119-2121
Author(s):  
Zhong Yang Liu ◽  
Wei Chen ◽  
Peng Fei Li
Keyword(s):  
Seismic Isolation ◽  
Shock Absorber ◽  
Steel Structure ◽  
Light Weight ◽  
Mechanism Analysis ◽  
Existing Building ◽  
Engineering Designs ◽  
Lead Rubber Bearings ◽  
Rubber Bearings ◽  
Technical Measures

Light-weight steel structure story-adding is a widely used technology in house reconstruction. In this paper, it introduces an technique that using seismic isolation theory in story-adding buildings using light-weight steel structure. On the basis of mechanism analysis, a number of lead rubber bearings（LRB）are set between the top storey of existing building and the newly light steel structure, and the upgraded building is developed as a TMD shock absorber system. Combined a project instance, the relevant technical measures and detail constitutions are given. It should be reference to storey-adding engineering designs.

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