Recorded and Numerical Strong Motion Response of a Base-Isolated Bridge

2004 ◽  
Vol 20 (2) ◽  
pp. 309-332 ◽  
Author(s):  
B. Bessason ◽  
E. Haflidason
Keyword(s):  
Peak Ground Acceleration ◽  
Base Isolation ◽  
Strong Motion ◽  
Seismic Protection ◽  
Bridge Site ◽  
Ground Acceleration ◽  
Lead Rubber Bearings ◽  
Rubber Bearings ◽  
Isolated Bridge ◽  
Concrete Deck

Since 1983, 12 Icelandic bridges have been base isolated for seismic protection. Lead-rubber bearings have been used in all the cases. The Thjorsa River Bridge, built in 1950 and retrofitted with base isolation in 1991, is instrumented by strong-motion accelerometers. The bridge has one 83-m-long main span and two 12-m-long approach spans. Only the main span, a steel arch truss with concrete deck, is base isolated. In June 2000, two major earthquakes of magnitude 6.6 and 6.5 occurred in South Iceland; the epicenter was close to the Thjorsa River Bridge. In the first earthquake, a peak ground acceleration of 0.53 g was recorded at the bridge site, and in the second earthquake, a peak ground acceleration of 0.84 g was recorded. The Thjorsa River Bridge survived the earthquakes without any serious damage and was open for traffic immediately after the earthquakes.

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.

scholarly journals Seismic Hazard of the Uttarakhand Himalaya, India, from Deterministic Modeling of Possible Rupture Planes in the Area

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Anand Joshi ◽  
Ashvini Kumar ◽  
Heriberta Castanos ◽  
Cinna Lomnitz
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Strong Motion ◽  
Semiempirical Method ◽  
Empirical Method ◽  
Attenuation Relation ◽  
Ground Acceleration ◽  
Important Region ◽  
Semi Empirical ◽  
Uttarakhand Himalaya

This paper presents use of semiempirical method for seismic hazard zonation. The seismotectonically important region of Uttarakhand Himalaya has been considered in this work. Ruptures along the lineaments in the area identified from tectonic map are modeled deterministically using semi empirical approach given by Midorikawa (1993). This approach makes use of attenuation relation of peak ground acceleration for simulating strong ground motion at any site. Strong motion data collected over a span of three years in this region have been used to develop attenuation relation of peak ground acceleration of limited magnitude and distance applicability. The developed attenuation relation is used in the semi empirical method to predict peak ground acceleration from the modeled rupture planes in the area. A set of values of peak ground acceleration from possible ruptures in the area at the point of investigation is further used to compute probability of exceedance of peak ground acceleration of values 100 and 200 gals. The prepared map shows that regions like Tehri, Chamoli, Almora, Srinagar, Devprayag, Bageshwar, and Pauri fall in a zone of 10% probability of exceedence of peak ground acceleration of value 200 gals.

Strong-Motion Data from Structural Response Recorders in Indian Earthquakes

2012 ◽  
Vol 28 (1) ◽  
pp. 77-103 ◽  
Author(s):  
Sudhir K. Jain ◽  
A. D. Roshan ◽  
Siddharth Yadav ◽  
Sonam Srivastava ◽  
Prabir C. Basu
Keyword(s):  
Peak Ground Acceleration ◽  
Structural Response ◽  
Time History ◽  
Strong Motion ◽  
Ground Acceleration ◽  
Motion Data ◽  
The Past ◽  
Simple Instrument ◽  
Low Costs ◽  
The 1960S

In the 1960s several hundred structural response recorders (SRR) were installed all over India. An SRR is a simple instrument consisting of six seismoscopes that provide “maximum response” during an earthquake, without providing the time history. In the past earthquakes, these SRRs have provided several hundred records but they have not been effectively utilized for hazard studies because the measurements from these instruments are considered crude. This paper compares the data obtained from SRRs with that from more modern strong-motion accelerographs (SMAs) for four earthquakes in India. It is shown through statistical analysis that the response obtained from the SRRs is comparable to that from the SMAs. A method has been presented for estimating peak ground acceleration (PGA) from SRR data. Thus, it is shown that SRRs can provide a substantial amount of PGA data for attenuation studies. Many countries may find SRRs useful because of the low costs associated with their manufacture and maintenance.

Non-Parameter System Identification of Isolated Bridge by Neural Networks Algorithm

2007 ◽  
Author(s):  
W. L. Chiang ◽  
J. P. Pu ◽  
T. Y. Liu
Keyword(s):  
Neural Networks ◽  
Dynamic Properties ◽  
Back Propagation ◽  
Nonlinear Behavior ◽  
Back Propagation Algorithm ◽  
Parameter System ◽  
Lead Rubber Bearings ◽  
Rubber Bearings ◽  
Isolated Bridge ◽  
Central Weather Bureau

The objective of this theme is to non-parameter identify and to compare the dynamic properties of the Lion-head river bridge located at Chia-I. The east bound of the bridge is designed and constructed as conventional, and the west bound as bridge isolated by lead-rubber bearings. Signals collected from the accelerometers installed on the bridge by the Central Weather Bureau will be processed. Back-propagation algorithm of Neural networks will be adopted and the nonlinear behavior of lead-rubber bearings will be simulated.

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.

Attenuation relationship for estimation of peak ground horizontal acceleration using data from strong-motion arrays in India

1998 ◽  
Vol 88 (4) ◽  
pp. 1063-1069
Author(s):  
M. L. Sharma
Keyword(s):  
Regression Model ◽  
Peak Ground Acceleration ◽  
Strong Motion ◽  
Attenuation Relationship ◽  
Ground Acceleration ◽  
Data Set ◽  
Hypocentral Distance ◽  
Horizontal Acceleration ◽  
Attenuation Relationships ◽  
Using Data

Abstract An attenuation relationship for peak horizontal ground accelerations for Himalayan region in India has been developed. The data base consists of 66 peak ground horizontal accelerations from five earthquakes recorded by strong-motion arrays in India. The present analysis uses a two-step stratified regression model. The attenuation relationship proposed is log ( A ) = − 1.072 + 0.3903 M − 1.21 log ( X + e 0.5873 M ) , where A is the peak ground acceleration (g), M is the magnitude, and X is the hypocentral distance from the source. The residual sum of squares is 0.14. Comparison with other such attenuation relationships have been made. The proposed relationship giving lesser values at shorter distances compared to other relationships needs further investigation with a larger data set. The attenuation relationship needs upgradation when more data become available in future.

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