Comparison of Earthquake Simulator Test Results with the SEAONC Tentative Seismic Isolation Design Requirements

1990 ◽  
Vol 6 (2) ◽  
pp. 403-417 ◽  
Author(s):  
Michael C. Griffith ◽  
Ian D. Aiken ◽  
James M. Kelly
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Low Frequency ◽  
Frame Structure ◽  
Wall Structure ◽  
Elastomeric Bearings ◽  
Earthquake Simulator ◽  
Isolation Systems ◽  
Structural Engineers ◽  
Steel Frame Structure

Earthquake simulator tests were performed on a 1/5-scale, 6-story reinforced concrete shear-wall structure and a 1/4-scale, 9-story braced steel frame structure. The structures were supported by five different base isolation systems which consisted of various types and combinations of elastomeric bearings. The main objective of this study was to compare the peak experimental displacements of the base isolation systems tested with values given by the tentative base isolation design provisions proposed by the Seismology Committee of the Structural Engineers Association of Northern California (SEAONC). Comparisons of experimental results and values from the SEAONC base isolation design formula for displacements indicated that the formula is generally conservative, even for predominantly low frequency earthquake motions, provided the ground motion coefficient Av (based on the effective peak velocity as defined by ATC 3-06) is used in the design equation for base-isolated structures with periods greater than 1 second.

Base-Isolated Multi-Storey Reinforced Concrete Frame Structure Modal Analysis

2012 ◽  
Vol 204-208 ◽  
pp. 869-871
Author(s):  
Cai Hua Wang ◽  
Hui Jian Li ◽  
Jian Feng Wu
Keyword(s):  
Reinforced Concrete ◽  
Modal Analysis ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Frame Structure ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Reinforced Concrete Frame Structure ◽  
Before And After ◽  
Isolation Device

The multi-storey reinforced concrete frame structure used lead rubber pad as the base isolation device. The paper had modal analysis of base-isolated multi-storey reinforced concrete frame structure using the ANSYS software. Comparing the frequency and vibration mode before and after isolation under El-Centro wave, It concluded the leader rubber pad have seismic isolation effect for multi-storey reinforced concrete frame structure .

Comparative Studies of Base Isolation Systems Featured with Lead Rubber Bearings and Friction Pendulum Bearings

2016 ◽  
Vol 846 ◽  
pp. 114-119
Author(s):  
Arati Pokhrel ◽  
Jian Chun Li ◽  
Yan Cheng Li ◽  
Nicos Maksis ◽  
Yang Yu
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Time History ◽  
Elastic Base ◽  
Base Shear ◽  
Isolation Technique ◽  
Rubber Bearing ◽  
Lead Rubber Bearing ◽  
Isolation Systems ◽  
Friction Pendulum

Due to the fact that safety is the major concern for civil structures in a seismic active zone, it has always been a challenge for structural engineers to protect structures from earthquake. During past several decades base isolation technique has become more and more popular in the field of seismic protection which can be adopted for new structures as well as the retrofit of existing structures. The objective of this study is to evaluate the behaviours of the building with different seismic isolation systems in terms of roof acceleration, elastic base shear and inter-storey drift under four benchmark earthquakes, namely, El Centro, Northridge, Hachinohe and Kobe earthquakes. Firstly, the design of base isolation systems, i.e. lead rubber bearing (LRB) and friction pendulum bearing (FPB) for five storey RC building was introduced in detail. The non-linear time history analysis was performed in order to determine the structural responses whereas Bouc-Wen Model of hysteresis was adopted for modelling the bilinear behaviour of the bearings. Both isolation systems increase the fundamental period of structures and reduces the spectral acceleration, and hence reduces the lateral force cause by earthquake in the structures, resulting in significant improvement in building performance; however the Lead Rubber Bearing provided the best reduction in elastic base shear and inter-storey drift (at first floor) for most of the benchmark earthquakes. For the adopted bearing characteristics, FPB provided the low isolator displacement.

The Modal Analysis of a Multilayer Concave-Convex Irregular Reinforced Concrete Frame Structures before and after Seismic Isolation

2013 ◽  
Vol 339 ◽  
pp. 632-634
Author(s):  
Fang Zhang
Keyword(s):  
Reinforced Concrete ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Frame Structure ◽  
Frame Structures ◽  
Reinforced Concrete Frame ◽  
Cycle Frequency ◽  
Concrete Frame ◽  
Before And After ◽  
Reinforced Concrete Frame Structures

It used lead core type laminated rubber pad as a base isolation device. Using the ANSYS software, it analyzed the modality of a multilayer concave-convex irregular reinforced concrete frame structures before and after seismic isolation. Comparison of the cycle, frequency and modal participation mass coefficient of the multilayer concave-convex irregular reinforced concrete frame structure before and after isolation in Kobe wave. It concluded that the lead laminated rubber bearings for multilayer concave-convex irregular reinforced concrete frame structures have seismic isolation effect.

Study on Performance Evaluation of MEMS Sensors and Data Integration Methods for Expected Use to Determine Damage Degrees of Existing Structures

2017 ◽  
Vol 12 (5) ◽  
pp. 858-867 ◽  
Author(s):  
Tomohiro Sasaki ◽  
◽  
Koichi Kajiwara ◽  
Takuzo Yamashita ◽  
Takuya Toyoshi
Keyword(s):  
Performance Evaluation ◽  
Structural Damage ◽  
Large Scale ◽  
Earth Science ◽  
Frame Structure ◽  
Micro Electro Mechanical Systems ◽  
Strong Earthquakes ◽  
Existing Structures ◽  
Earthquake Simulator ◽  
Steel Frame Structure

The shake table test of small-scaled steel frame structure was conducted using large-scale earthquake simulator at the National Research Institute for Earth Science and Disaster Resilience (NIED) in Tsukuba, Ibaragi. This paper presents the performance evaluation of Micro Electro Mechanical Systems (MEMS) type accelerometers, which are recently being used in various fields, comparing with the conventional servo type accelerometers. In addition, this paper discussed the integration method of the measured acceleration into displacements, which is suitable for structural damage evaluation due to strong earthquakes.

Base Isolation: Linear Theory and Design

1990 ◽  
Vol 6 (2) ◽  
pp. 223-244 ◽  
Author(s):  
James M. Kelly
Keyword(s):  
Linear Theory ◽  
Seismic Isolation ◽  
Large Scale ◽  
Base Isolation ◽  
Ground Movement ◽  
Engineering Profession ◽  
Shake Table Testing ◽  
Static Testing ◽  
Degree Of Acceptance ◽  
Isolation Systems

The idea that a building can be uncoupled from the damaging effects of the ground movement produced by a strong earthquake has appealed to inventors and engineers for more than a century. Many ingenious devices have been proposed to achieve this result, but very few have been implemented and the concept now referred to as base isolation or seismic isolation has yet to be generally accepted by the engineering profession. Although most of the proposed systems are unacceptably complicated, in recent years a few practical systems have been developed and implemented. While some of these systems have been tested on large-scale shaking tables, none have to date been tested as-built by a strong earth tremor. The shake table testing and related static testing of full-scale components such as isolation bearings, however, has led to a certain degree of acceptance by the profession and it is possible that the number of practical implementations of base isolation will increase quite dramatically in the next few years. This paper describes recent implementations of base isolation and describes an approximate linear theory of isolation which can be used for the design of base isolation systems that use multilayer elastomeric isolators.

New Seismic Isolation Systems for Floating Houses

2012 ◽  
Author(s):  
C. S. Tsai ◽  
H. C. Su ◽  
W. C. Liao ◽  
Yan-Ming Wang
Keyword(s):  
Climate Change ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Isolation System ◽  
Sea Levels ◽  
Earthquake Resistant ◽  
Earthquake Resistant Structures ◽  
Base Isolation System ◽  
Isolation Systems ◽  
Seismic Isolation Systems

Inhabitable land has been decreasing due to the continual rise in sea levels caused by global warming. In response to this climate change, we need to consider looking for living spaces on water surfaces as well as building earthquake-resistant structures, particularly in flood and earthquake prone areas. This paper presents an experimental study on a new base isolation system in mitigating the response of a floating house that is located in a port. Experimental results show that the seismic response of the floating house was considerably reduced by the proposed isolation system with a proper displacement limit.

Performance of Elastomers in Isolation Bearings: A Literature Review

1992 ◽  
Vol 8 (2) ◽  
pp. 279-303 ◽  
Author(s):  
Andrew W. Taylor ◽  
Albert N. Lin ◽  
Jonathan W. Martin
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
The United States ◽  
High Energy ◽  
Laboratory Findings ◽  
Elastomeric Bearings ◽  
Performance Requirements ◽  
Long Term Performance ◽  
Term Performance

Laminated elastomeric bearings have been used for about 30 years in the United States to isolate bridge substructures from the lateral forces induced by shrinkage and creep of their superstructures. More recently, elastomeric bearings have been increasingly employed in buildings and bridges as a means of decoupling the structure from seismic ground motions. Since most buildings and bridges have service lives of at least 30 to 60 years, questions about the long-term behavior of base-isolation bearings arise. This paper presents a review of literature relating to the long term performance of the elastomers used in seismic isolation bearings. Bearing performance requirements are discussed and material characteristics and fabrication procedures are outlined. Field experience and laboratory findings are reviewed. Finally, long-term environmental effects are discussed, including ozone degradation, corrosion, temperature effects, and the influence of bombardment of elastomers by high energy radiation.

scholarly journals Base isolation design and analysis for the 7-story apartment building “Stepanakert-sections-4-5” with R/C monolithic load-bearing walls and asymmetric plan

2020 ◽  
Vol 5 (2) ◽  
pp. 047-056
Author(s):  
Mikayel G. Melkumyan
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Apartment Building ◽  
Isolation System ◽  
Load Bearing ◽  
Seismic Code ◽  
Fitness Clubs ◽  
Manufacturing Testing ◽  
Isolation Systems ◽  
The Cost

In recent years seismic isolation technologies in Armenia were extensively applied in construction of multi-story residential, medical, hotel, airport, and business center complexes with parking floors and with floors envisaged for offices, shopping centers, fitness clubs, etc. To date there are 55 seismic isolated buildings in the country newly constructed or retrofitted by base or roof isolation systems. Of this number of buildings 48 were erected thanks to the works of the author of this paper and in nowadays Armenia is well known as a country where seismic (base and roof) isolation systems are widely implemented in civil construction. The number of seismically isolated buildings per capita in Armenia is one of the highest in the world – second after Japan. The paper given below emphasizes achievements also in local manufacturing/testing of seismic isolation laminated rubber-steel bearings (SILRSBs). Several remarkable projects on construction of base isolated buildings are briefly mentioned in the paper to demonstrate the experience accumulated in Armenia. Based on the gained experience further developments take place and unique base isolation structural concepts and technologies created by the author are applied more and more in construction of new buildings. In this paper base isolation design and analysis by the Armenian Seismic Code for the 7-story apartment building to be constructed in Stepanakert is described. This will be a first application of base isolation technology to a building the bearing system of which consists of reinforced concrete (R/C) monolithic load-bearing walls and building has an asymmetric plan. It is stated that suggested seismic isolation strategy will reduce the cost of construction of the given building on about 35% in comparison with the cost of conventional construction. Obtained results indicate the high effectiveness of the proposed structural concept of isolation system and the need for further improvement of Seismic Code provisions regarding the values of the reduction factors.

SEISMIC CAPACITY OF MEDIUM SIZE CONTINUOUS BRIDGES WITH LEAD-RUBBER BEARINGS

2019 ◽  
Vol 3 (Special Issue on First SACEE'19) ◽  
pp. 199-206
Author(s):  
Bertha Olmos ◽  
José Jara ◽  
José Luis Fabián
Keyword(s):  
Seismic Performance ◽  
Seismic Vulnerability ◽  
Base Isolation ◽  
Elastic Behaviour ◽  
Medium Size ◽  
Nonlinear Behaviour ◽  
Seismic Capacity ◽  
Damage Scenarios ◽  
Isolation Systems ◽  
Rubber Bearings

This paper investigates the effects of the nonlinear behaviour of isolation pads on the seismic capacity of bridges to identify the parameters of base isolation systems that can be used to improve seismic performance of bridges. A parametric study was conducted by designing a set of bridges for three different soil types and varying the number of spans, span lengths, and pier heights. The seismic responses (acceleration, displacement and pier seismic forces) were evaluated for two structural models. The first model corresponded to the bridges supported on elastomeric bearings with linear elastic behaviour and the second model simulated a base isolated bridge that accounts for the nonlinear behaviour of the system. The seismic demand was represented with a group of twelve real accelerograms recorded on the subduction zone on the Pacific Coast of Mexico. The nonlinear responses under different damage scenarios for the bridges included in the presented study were estimated. These results allow determining the seismic capacity of the bridges with and without base isolation. Results show clearly the importance of considering the nonlinear behaviour on the seismic performance of bridges and the influence of base isolation on the seismic vulnerability of medium size bridges.

Study on Rational Ratios of Lateral Stiffness for Masonry Building with Frame Structure at First Two Stories

2012 ◽  
Vol 174-177 ◽  
pp. 2012-2015
Author(s):  
Xiao Long Zhou ◽  
Ying Min Li ◽  
Lin Bo Song ◽  
Qian Tan
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Shear Wall ◽  
Calculation Model ◽  
Frame Structure ◽  
Wall Structure ◽  
Masonry Building ◽  
Lateral Stiffness ◽  
Stiffness Ratio ◽  
Lateral Stiffness Ratio

There are two typical seismic damage characteristics to the masonry building with frame shear wall structure at first two stories, and the lateral stiffness ratio of the third storey to the second storey is one of the key factors mostly affecting the seismic performance of this kind of building. However, some factors are not considered sufficiently in current Chinese seismic codes. According to the theory of performance-based seismic design, the seismic performance of this kind of structure is analyzed in this paper by taking time-history analysis on models which with different storey stiffness ratios. The results show that when the lateral stiffness ratio controlled in a reasonable range, the upper masonry deformation can be ensured in a range of elastic roughly, and the bottom frame can be guaranteed to have sufficient deformation and energy dissipation capacity. Finally, according to the seismic performance characteristics of masonry building with frame shear wall structure at first two stories, especially the characteristics under strong earthquakes, a method of simplified calculation model for the upper masonry is discussed in this paper.

Sign in / Sign up

Export Citation Format

Share Document