On the Effectiveness of Two Isolation Systems for the Seismic Protection of Elevated Tanks

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Fabrizio Paolacci
Keyword(s):  
Time History ◽  
Seismic Protection ◽  
Base Shear ◽  
Lumped Mass ◽  
High Damping Rubber Bearings ◽  
Elevated Tanks ◽  
High Damping Rubber ◽  
Isolation Systems ◽  
The Stability ◽  
Rubber Bearings

This paper deals with the effectiveness of two isolation systems for the seismic protection of elevated steel storage tanks. In particular, the performance of high damping rubber bearings (HDRB) and friction pendulum isolators (FPS) has been analyzed. As case study, an emblematic example of elevated tanks collapsed during the Koaceli Earthquake in 1999 at Habas pharmaceutics plant in Turkey is considered. A time-history analysis conducted using lumped mass models demonstrates the high demand in terms of base shear required to the support columns and their inevitable collapse due to the insufficient shear strength. A proper design of HDRB and FPS isolator according to the EN1998 and a complete nonlinear analysis of the isolated tanks proved the high effectiveness of both isolation systems in reducing the response of the case tank. Actually, the stability conditions imposed by the code and a reduced level of convective base shear obtained with the second isolation typology suggests the use of FPS isolators rather than HDRB devices.

On the Effectiveness of Two Isolation Systems for the Seismic Protection of Elevated Tanks

2014 ◽  
Author(s):  
Fabrizio Paolacci
Keyword(s):  
Time History ◽  
Seismic Protection ◽  
Base Shear ◽  
Lumped Mass ◽  
Isolation System ◽  
High Damping Rubber Bearings ◽  
Elevated Tanks ◽  
High Damping Rubber ◽  
Isolation Systems ◽  
Rubber Bearings

This paper deals with the effectiveness of two isolation system for the seismic protection of elevated steel storage tanks. In particular the performance of High Damping Rubber Bearings and Friction Pendulum isolators has been analyzed. As case study an emblematic example of elevated tanks collapsed during the Koaceli Earthquake in 1999 at Habas Pharmaceutics plant in Turkey has been considered. A time-history analysis conducted using lumped mass models demonstrated the high demand in terms of base shear required to the support columns and their inevitable collapse due to the insufficient shear strength. A proper design of HDRB and FPS isolator and a complete non-linear analysis of the isolated tanks proved the high effectiveness of both isolation systems in reducing the response of the case tank. Actually, a reduced level of displacements of isolators and a reduced level of convective base shear obtained with the second isolation typology, suggested the used of FPS isolators rather than HDRB.

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.

EFFECTIVENESS OF SEISMIC ISOLATION FOR CABLE-STAYED BRIDGES

2006 ◽  
Vol 06 (01) ◽  
pp. 77-96 ◽  
Author(s):  
B. B. SONEJI ◽  
R. S. JANGID
Keyword(s):  
Seismic Response ◽  
Seismic Isolation ◽  
Damping Ratio ◽  
Time History ◽  
Time Interval ◽  
Lumped Mass ◽  
Pendulum System ◽  
Isolation Systems ◽  
Rubber Bearings ◽  
Cable Stayed Bridges

This paper investigates the effectiveness of elastomeric and sliding types of isolation systems for the seismic response control of cable-stayed bridges. A simplified two-dimensional lumped-mass finite-element model of the Quincy Bay-view Bridge at Illinois was developed for the investigation. The seismic isolation of cable-stayed bridges is achieved using three different isolators, namely, high damping rubber bearings (HDRB), lead rubber bearings (LRB) and friction pendulum system (FPS). Time history analysis is performed for the bridge with four different earthquake ground motions applied in the longitudinal direction using Newmark's method with linear variation of acceleration over the time interval. The seismic response of the isolated cable-stayed bridge is compared with that of the bridge with no isolation system. The results show that the isolation systems are effective for reducing the absolute acceleration of the deck and the base shear response of the tower. Further, a parametric study is performed by varying the damping ratio, yield strength and friction coefficient of HDRB, LRB and FPS to investigate the influence of these parameters on the seismic response of the bridge. From such a study, optimal values can be found for the isolators for reducing the bridge responses.

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).

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

2005 ◽  
Author(s):  
Massimo Forni
Keyword(s):  
Seismic Isolation ◽  
Shaking Table ◽  
Seismic Protection ◽  
Piping System ◽  
Fiber Reinforced ◽  
Shaking Table Tests ◽  
Time Histories ◽  
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 devices 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. 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. Validation through shaking table tests of the effectiveness of the isolation systems on the spherical mock-up (Figure 1), and the related piping system equipped with flexible joints (Figure 2), had been performed. Two types of seismic input have been applied, both synthesized from the 5% damping spectra of EC8 (medium and soft soils); the target peak acceleration value of the time histories was 0.4 g. 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 both time histories and at three different level of filling to verify the sloshing behavior in the sphere and the effectiveness of the isolation systems at levels of filling different from the design one (full sphere). Comparison among all the above mentioned conditions could be done. The presentation will show the main results of the shaking table campaign.

Non-Linear Behaviour of Base-Isolated Building Supported on Flexible Soil under Damaging Earthquakes

2011 ◽  
Vol 488-489 ◽  
pp. 142-145
Author(s):  
Sayed Mahmoud ◽  
Per Erik Austrell ◽  
Robert Jankowski
Keyword(s):  
Structural Damage ◽  
Seismic Isolation ◽  
Soft Soil ◽  
High Damping Rubber Bearings ◽  
Non Linear ◽  
Linear Behaviour ◽  
Soil Flexibility ◽  
High Damping Rubber ◽  
Isolation Systems ◽  
Rubber Bearings

Seismic isolation is a strategy to reduce damage of structures exposed to devastating earthquake excitations. Isolation systems, applied at the base of buildings, lower the fundamental frequency of the structure below the range of dominant frequencies of the ground motion as well as allow to dissipate more energy during structural vibrations. The effectiveness of the base-isolated buildings in damage reduction has been confirmed numerically for the models of structures with fixed supports. The aim of the present paper is to show the results of the non-linear analysis of the response of a base-isolated building supported on soft soil incorporating soil-structure interaction. The detailed study has been conducted for the building equipped with high damping rubber bearings used as isolation devices. The results of numerical simulations demonstrate that soil flexibility has a significant influence on the behaviour of isolated base of the structure. Considering the flexibility of soil significantly affects the rigid superstructure response lowering its potential to reduce structural damage.

Seismic Performance of a Multi-Span RC Highway Bridge with High Damping Rubber Bearings

2013 ◽  
Vol 540 ◽  
pp. 69-78 ◽  
Author(s):  
Yong Li ◽  
Jin Jie Wang ◽  
Jing Bo Liu
Keyword(s):  
Seismic Performance ◽  
Damping Ratio ◽  
Time History ◽  
Highway Bridge ◽  
Seismic Excitations ◽  
High Damping Rubber Bearings ◽  
History Analysis ◽  
High Damping Rubber ◽  
Dynamic Time ◽  
Rubber Bearings

Based on the nonlinear dynamic time history analysis, a multi-span RC highway bridge with high damping rubber bearings was studied, to investigate the damping ratio and seismic performance of the bridge and high damping rubber bearings compared with the rubber bearings. Results show that the application of high damping rubber bearings can reduce the seismic response of substructures of the bridge under longitudinal and transversal seismic excitations to some extent. But what is more important is that high damping rubber bearings wont suffer shear and displacement failure which may happen on rubber bearings. As a result, the pounding response and residual displacement can be dispelled.

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