Analysis and Demonstrative Application of a Base Isolation/Supplemental Damping Technology

2008 ◽  
Vol 24 (3) ◽  
pp. 775-793 ◽  
Author(s):  
Stefano Sorace ◽  
Gloria Terenzi
Keyword(s):  
Base Isolation ◽  
Numerical Models ◽  
Ground Acceleration ◽  
Fixed Base ◽  
Supplemental Damping ◽  
And Performance ◽  
High Damping Rubber ◽  
Design Earthquake ◽  
Rubber Bearings ◽  
The Cost

As a concluding step of several studies on a special base isolation/supplemental damping system, where pressurized fluid viscous spring-dampers are coupled to steel-Teflon sliders, the system was applied for the first time to a demonstrative strategic building in Italy. A final experimental campaign was developed to assess the interference of the dissipative actions of the two component devices. The campaign confirmed the linear additive combination implicitly assumed in relevant numerical models. The design and performance evaluation analyses performed on the building showed that maximum base displacements were only just below 45 mm, for the basic design earthquake level. As a result, very simple joints for all the facilities were used. For the same earthquake level, reduction factors of 2.48 and 2.12 on the superstructure response accelerations were obtained for the two main directions in plan as compared to peak ground acceleration. Low base displacement values, and a totally elastic superstructure response also emerged for the maximum earthquake level considered, as well as for the most demanding Italian historical near-fault ground motions introduced as inputs in the final verification analyses. The cost of the building structure resulted to be around 10% lower than the cost of a fixed-base traditional design, as well as of a base isolated structure incorporating high damping rubber bearings.

Seismic Analysis and Comparison of Different Base Isolation Systems for a Multi-Storey RC Building with Irregularities in Plan

2012 ◽  
Vol 594-597 ◽  
pp. 1788-1799 ◽  
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis
Keyword(s):  
Base Isolation ◽  
Seismic Analysis ◽  
Cyclic Behavior ◽  
Isolation System ◽  
High Damping Rubber Bearings ◽  
Fixed Base ◽  
Base Isolation System ◽  
High Damping Rubber ◽  
Isolation Systems ◽  
Rubber Bearings

In the present paper the dynamic nonlinear analysis for a 3D base isolated structure is illustrated. A base isolated reinforced concrete building is designed and verified according to the European seismic codes such that the superstructure remains almost completely elastic and the nonlinear elements are localized only in the base isolation system. Nonlinear hysteretic models have been adopted to reproduce the cyclic behavior of the isolators. Two different base isolation systems are considered and their performances are compared for evaluating the behaviour of a base isolated building, highly irregular in plan, in presence of a seismic excitation defined with recorded accelerograms which characterize the bi-directional ground motions. The isolation system has been realized with a combination in parallel of elastomeric bearings and sliding devices. In the first analyzed isolation system we have used the High Damping Rubber Bearings (HDRB) and in the second analyzed isolation system we have used the Lead Rubber Bearings (LRB). Finally a comparative analysis between the base isolated structure with hybrid base isolation systems and the conventional fixed base structure is detailed.

scholarly journals Responses of Building Base Isolated With High Damping Rubber Bearings

2019 ◽  
Vol 8 (9) ◽  
pp. 1287-1292
Keyword(s):  
Seismic Isolation ◽  
Design Procedure ◽  
Hysteretic Model ◽  
Base Shear ◽  
Ground Acceleration ◽  
Element Analysis ◽  
High Damping Rubber Bearings ◽  
Fixed Base ◽  
High Damping Rubber ◽  
Rubber Bearings

Seismic isolation is one of the most efficient techniques to protect structures against earthquakes. Rubber bearings are suitable for low-rise and medium-rise buildings due to its durability and easy fabrication. This paper presents the hori-zontal response of a six-storey base-isolated building using high damping rubber bearings (HDRB) under two ground motions of earthquakes as types I and II in JRA (2002) by finite element analysis. In this analysis, these bearings are mod-elled by the bilinear hysteretic model which is indicated in JRA and AASHTO. Comparison of horizontal response including base shear force and roof level acceleration between the two cases: base-isolated building and fixed-base building is carried out to evaluate the effectiveness of the use of HDRB on the protection of buildings from earthquakes. The numerical results show that the peak value of roof floor acceleration of the fixed-base building is two times higher than that of the base-isolated building, and the floor accelerations depend on the peak values of ground acceleration. In addition, the step-by-step design procedure for deter-mining the size of HDRBs used for buildings is also presented in this paper.

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.

Seismic Rehabilitation of the Mackay School of Mines, Phase III, with Base Isolation

1990 ◽  
Vol 6 (2) ◽  
pp. 297-308 ◽  
Author(s):  
Douglas Way ◽  
Jack Howard
Keyword(s):  
Base Isolation ◽  
Unreinforced Masonry ◽  
Point Of View ◽  
Phase Iii ◽  
Isolation System ◽  
Seismic Rehabilitation ◽  
The North ◽  
Historic Monument ◽  
High Damping Rubber ◽  
Rubber Bearings

The original Mackay School of Mines Building was constructed in 1908. It is one of the original buildings of the University of Nevada, and is situated at the north end of the main quadrangle within the campus. Prominent in its location at University of Nevada and in appearance, the building is designated as a national historic monument. During the years of 1926 and 1956, significant structural alterations were made to the original building. Phase III work at the original Mackay School of Mines Building involves adding a library at the basement, with the balance of the building being remodeled for similar-type functions. Constructed mainly of unreinforced masonry, the seismic rehabilitation of the structure warrants careful attention. During the schematic phase of the work, both conventional strengthening and Base Isolation were explored as potential techniques with which to mitigate damage from earthquakes. Cost estimate of both schemes were also developed. From a preservationist point of view, there were definite advantages in the isolation design. Since the isolation system could filter out most of the damaging forces associated with earthquakes, none of the unreinforced masonry walls required strengthening. As a result, many of the original architectural features of the original building can be salvaged, maintaining the original quality of the building and its identity. For these reasons the Base Isolation option was selected as the seismic retrofit scheme. This paper illustrates the Base Isolation design for the Mackay School of Mines, a historical structure constructed of unreinforced masonry. The isolation system consists of high-damping rubber bearings in combination with sliding elements.

Shaking Table Tests on a Spherical Tank Mock-Up Provided With Seismic Isolation and Flexible Piping Connections

2006 ◽  
Author(s):  
Massimo Forni ◽  
Alessandro Poggianti ◽  
Giulia Bergamo ◽  
Fabrizio Gatti
Keyword(s):  
Seismic Isolation ◽  
Shaking Table ◽  
Seismic Protection ◽  
Piping System ◽  
Fiber Reinforced ◽  
Shaking Table Tests ◽  
Fixed Base ◽  
High Damping Rubber ◽  
Isolation Systems ◽  
Rubber Bearings

The Project INDEPTH (Development of INnovative DEvices for Seismic Protection of PeTrocHemical Facilities), supported by the European Commission, has the objective of developing and applying innovative seismic isolation and/or dissipation systems for critical structures at petrochemical facilities. In the framework of INDEPTH, integrated seismic protection systems have been conceived, developed and tested. They are aimed at protecting liquid-filled structures (product storage, spherical and LNG tanks), with new devices (fiber-reinforced isolators, buckling reinforced braces) specific for each application and new flexible piping couplings, to compensate the displacements resulting from the use of isolation systems. The research program has been focused on the selection of critical structures, the design and manufacturing of the devices, the numerical assessment and the experimental validation through shaking table tests [1–4]. A quantification of technical/economical/safety benefits with respect to the conventional state-of-the-art measures presently adopted and potential application to retrofitting has been performed. This paper describes the validation through shaking table tests of the effectiveness of the isolation systems on a spherical mock-up and the related piping system equipped with flexible joints. Different configurations of the mock-up have been tested, such as: fixed base, isolated base with High Damping Rubber Bearings, Fiber Reinforced Rubber Bearings and Lead Rubber Bearings. Furthermore, each configuration has been tested for three different level of filling to verify the sloshing behavior in the sphere and the effectiveness of the isolation systems at filling levels different from the design one (full sphere).

scholarly journals THE INVESTIGATION BASE ISOLATOR IN CONTROLLING THE RESPONSE OF THE STRUCTURES DURING EARTHQUAKES

2018 ◽  
Vol 1 (18) ◽  
Author(s):  
Barghlame Hadi ◽  
Gavgani Hojjat Hashempour
Keyword(s):  
Base Isolation ◽  
Comparative Investigation ◽  
Pendulum System ◽  
Rubber Bearing ◽  
Lead Rubber Bearing ◽  
Fixed Base ◽  
High Damping Rubber ◽  
Isolation Systems ◽  
Friction Pendulum ◽  
Base Isolators

Base isolation systems are among the most successful and widely applied methods of mitigatingstructural vibration and damage during seismic events. These systems have been installed in numerousfull-scale structures all around. There are three principal types of base isolators: Lead Rubber Bearing(LRB), High Damping Rubber Bearing (HDRB), and Friction Pendulum System (FPS). It is necessaryto extensively examine the response of different LRB isolators—by combining them with re-centeringand damping properties for isolated steel frame buildings experiencing several NF ground motions. Thepresent research uses comparative-descriptive methodology and application in terms of objectives. Thedata needed for the study were collected using library references and through reviewing related studiesconducted in the past in the same field.Results of the current comparative investigation indicated significant reductions in the storey drift,shear, and acceleration and increment in the storey displacement. According to the findings of thecurrent study, base isolators provide flexibility to massive structures against earthquakes. Thesestructures are situated on rigid soils. Moreover, base isolation was found to be the most effective incontrolling the response of the structures during earthquakes. Finally, shear, storey drift, and storeydisplacement reduce due to the use of base isolators as compared to the fixed-base structure.

Effects of Isolation Damping on Stochastic Response of Structures with Nonlinear Base Isolators

1998 ◽  
Vol 14 (1) ◽  
pp. 95-114 ◽  
Author(s):  
R. S. Jangid ◽  
P. Banerji
Keyword(s):  
Sliding Friction ◽  
Base Isolation ◽  
Equivalent Linearization ◽  
Earthquake Intensity ◽  
Analytical Expression ◽  
Time Period ◽  
Stiffness Properties ◽  
Fixed Base ◽  
Optimum Material ◽  
Design Earthquake

Optimum isolator damping required to minimize absolute acceleration responses to stochastic ground motions in buildings with non-linear resilient-friction base isolation (R-FBI) devices is studied. Using a stochastic equivalent linearization technique, an analytical expression is developed for estimating optimum material damping values in an R-FBI system for a rigid superstructure. This optimum damping value depends on the effective time period and friction coefficient of the R-FBI system and the design earthquake intensity. The fixed base structural time period, damping, and the number of stories also affect the optimum isolator damping values, if the superstructure is flexible. However, the analytical expression mentioned above provides an upper-bound optimum isolator damping value for any superstructure with an R-FBI system subjected to a given earthquake intensity. Comparison of optimum damping values for a linear isolator and the R-FBI system, with identical lateral stiffness properties, illustrates the beneficial effect of sliding friction in reducing the optimum damping in the latter type of isolator, for a given earthquake intensity.

scholarly journals A New Experimental Manner to Determinate Design Parameters of High Damping Rubber Bearings

2019 ◽  
Vol 8 (9) ◽  
pp. 1293-1296
Keyword(s):  
Design Parameters ◽  
Damping Capacity ◽  
Shear Tests ◽  
Lap Shear ◽  
High Damping Rubber Bearings ◽  
High Damping Rubber ◽  
Rubber Bearings ◽  
High Flexibility ◽  
The Cost

High damping rubber bearings (HDRB) is an efficient technique developed to prevent or minimize damage to buildings during earthquakes. HDRB with high flexibility and high damping capacity have been widely applied in Japan. The high flexibility will be able to move the structures’ natural refequencies to shirk the resonance with excitation, while their high damping capability can reduce the corresponding displacement. In seismic design codes (AASHTO 2010, JRA 2004), the design parameters of HDRB are identified from a stress-strain loop of sinusoidal bearing experiment results. The specimens of HDRB are designed based on ISO 2005, however, the cost of these specimens is quite high. In this paper, a new test manner, namely lap shear tests with cheap cost is investigated to replace the bearing tests. The analytical results show that lap shear tests may be the alternative method for determination of design parameters of HDRB.

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