Design of base-isolated buildings

Author(s):  
Dario Pietra ◽  
Stefano Pampanin ◽  
Ron L. Mayes ◽  
Nicholas G. Wetzel ◽  
Demin Feng

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.

Author(s):  
R. Park

The past occurrence of earthquakes in New Zealand and the likelihood of a major earthquake in Christchurch are considered. The causes of damage by earthquakes are discussed and typical possible types of damage to building and bridge structures are described with reference to the 1995 Kobe earthquake. The design of building and bridge structures for earthquake resistance by the ductile design approach is covered, including performance criteria, structural configuration, design seismic forces, mechanisms of post-elastic deformation, capacity design, detailing of reinforcement for ductility and control of deflections. Design using base isolation and mechanical energy dissipating devices is also outlined. The extensive use of precast concrete in buildings in New Zealand is described. Finally the seismic assessment and upgrading of old structures and the earthquake resistance of lifelines of communities (transportation, utilities and communications) are briefly considered.


2021 ◽  
Vol 2070 (1) ◽  
pp. 012198
Author(s):  
Sajan K Jose ◽  
G S Anjali ◽  
Aarya S Nair ◽  
D A Adithya ◽  
Ananya Sony ◽  
...  

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.


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.


2012 ◽  
Vol 446-449 ◽  
pp. 3299-3303
Author(s):  
Xi Sen Fan ◽  
Ting Lei Tian

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.


Author(s):  
D. J. Dowrick ◽  
J. Babor ◽  
W. J. Cousins ◽  
R. I. Skinner

This paper describes the seismic hazard near the Wellington Fault in Petone, and the measures taken to protect a new printing press made of brittle cast iron against earthquake attack. The printing press, owned by Wellington Newspapers, was located just 20 m from the Wellington Fault. Mounting the specially designed building housing the press on a seismic isolation system, lead-rubber bearings, reduced the estimated loads and deflections on the press by a factor of 8-10 compared with the non-isolated case. As a result the press should suffer only modest damage in earthquake shaking somewhat stronger than that required by the New Zealand earthquake code for the design of buildings.


Author(s):  
Govardhan Bhatt ◽  
D. K. Paul ◽  
Shubhankar Bhowmick

Seismic base isolation is one of the most widely implemented and accepted seismic protection systems and is a relatively recent and evolving technology. The most common isolation system used is Laminated Lead Rubber Bearings (LLRB). They combine the function of isolation and energy dissipation in a single compact unit, giving structural support, horizontal flexibility, damping, and a re-centering force in a single unit. The force deformation behavior of LLRB is modeled as bilinear system with viscous damping. In this paper, a comprehensive design of LLRB is presented. Accurate evaluation of the structural properties and precise modeling of isolation devices are of utmost importance in predicting the response of the structure during the earthquakes. Base isolation has now been used in numerous buildings in countries like Italy, Japan, New Zealand, and USA. Base isolation is also useful for retrofitting of important buildings (like hospitals and historic buildings).


2004 ◽  
Vol 20 (2) ◽  
pp. 309-332 ◽  
Author(s):  
B. Bessason ◽  
E. Haflidason

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.


2019 ◽  
Vol 3 (Special Issue on First SACEE'19) ◽  
pp. 199-206
Author(s):  
Bertha Olmos ◽  
José Jara ◽  
José Luis Fabián

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.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yewon Song ◽  
Seulah Lee ◽  
Yuna Choi ◽  
Sora Han ◽  
Hyuna Won ◽  
...  

AbstractThe wearable electronics integrated with textile-based devices is a promising strategy to meet the requirements of human comfort as well as electrical performances. This research presents a design and development framework for a seamless glove sensor system using digital knitting fabrication. Based on the performance requirements of glove sensors for controlling a prosthetic hand, desirable design components include electrical conductivity, comfort, formfit, electrical sensitivity, and customizable design. These attributes are determined and achieved by applying appropriate materials and fabrication technologies. In this study, a digital knitting CAD/CAM system is utilized to meet the desired performance criteria, and two prototypes of the seamless glove sensor systems are successfully developed for the detection of both human and robotic finger motions. This digital knitting system will provide considerable potential for customized design development as well as a sustainable production process. This structured, systematic approach could be adapted in the future development of wearable electronic textile systems.


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