scholarly journals Suitable Friction Sliding Materials for Base Isolation of Masonry Buildings

2012 ◽  
Vol 19 (6) ◽  
pp. 1327-1339 ◽  
Author(s):  
Radhikesh P. Nanda ◽  
Pankaj Agarwal ◽  
Manish Shrikhande
Keyword(s):  
Base Isolation ◽  
Low Cost ◽  
Analytical Investigation ◽  
Seismic Protection ◽  
Experimental Investigations ◽  
Masonry Buildings ◽  
Isolation System ◽  
Sliding Interfaces ◽  
The Coefficient Of Friction ◽  
Base Isolation System

A feasibility study of friction base isolation system for seismic protection has been performed. Four different sliding interfaces, namely, green marble/High Density Poly Ethylene (HDPE), green marble/green marble, green marble/geosynthetic, and green marble/ rubber layers have been studied through experimental and analytical investigations. The experimental investigations show that the coefficient of friction values of these interfaces lies in the desirable range for seismic protection, i.e., 0.05 to 0.15. The analytical investigation reveals that most of these sliding interfaces are effective in reducing spectral accelerations up to 50% and the sliding displacement is restricted within plinth projection of 75 mm (3 in). Green marble and geosynthetic are found to be better alternatives for use in friction isolation system with equal effectiveness of energy dissipation and limiting the earthquake energy transmission to super structure during strong earthquake leading to a low cost, durable solution for earthquake protection of masonry buildings.

Seismic performance of a Low-Cost base isolation system for unreinforced brick Masonry buildings in developing countries

2021 ◽  
Vol 141 ◽  
pp. 106501
Author(s):  
Daniele Losanno ◽  
Nagavinothini Ravichandran ◽  
Fulvio Parisi ◽  
Andrea Calabrese ◽  
Giorgio Serino
Keyword(s):  
Developing Countries ◽  
Seismic Performance ◽  
Base Isolation ◽  
Low Cost ◽  
Brick Masonry ◽  
Masonry Buildings ◽  
Isolation System ◽  
Base Isolation System

Seismic Responses of a Building Isolated With Multiple Friction Pendulum System Subjected to Multi-Directional Excitations

2010 ◽  
Author(s):  
C. S. Tsai ◽  
Yung-Chang Lin ◽  
H. C. Su
Keyword(s):  
Base Isolation ◽  
Numerical Analyses ◽  
Good Tool ◽  
Isolation System ◽  
Pendulum System ◽  
Sliding Interfaces ◽  
Base Isolation System ◽  
Structural Responses ◽  
Friction Pendulum ◽  
Friction Pendulum System

In order to prevent a building from earthquake damage, a base isolation system called the multiple friction pendulum system (MFPS) which has numerous concave sliding interfaces is proposed to isolate a building from its foundation. Mathematical formulations have been derived to simulate the characteristic of the MFPS isolation system subjected to multi-directional excitations. By virtue of the derived mathematical formulations, the phenomena of the sliding motions of the MFPS isolator with several concave sliding interfaces under multi-directional earthquakes can be clearly understood. Also, numerical analyses of a building isolated with the MFPS isolator with several sliding interfaces have been conducted in this study to evaluate the efficiency of the proposed system in seismic mitigation. It has been proved through numerical analyses that structural responses have been reduced significantly and that the proposed system is a good tool to insure the safety of structures during earthquakes.

Seismic base isolation for steel structures

1985 ◽  
Vol 12 (1) ◽  
pp. 73-81
Author(s):  
S. F. Stiemer ◽  
B. B. Barwig
Keyword(s):  
Base Isolation ◽  
Steel Structures ◽  
Experimental Tests ◽  
Shaking Table ◽  
Earthquake Ground Motion ◽  
Experimental Investigations ◽  
Steel Buildings ◽  
Earthquake Excitation ◽  
Isolation System ◽  
Base Isolation System

Base isolation is a strategy for a design of buildings in areas where seismic loads govern. It enables the reduction of earthquake excitation to an acceptable level, without an increase of structural acceleration. This paper presents the results of the experimental investigations of various schemes of first-storey designs for steel buildings with base isolation.A scaled-down steel frame building was used for the shaking table tests, which were conducted in the Earthquake Simulator Laboratory of the University of British Columbia. The base-storey design was altered while the dynamic response of the frame was recorded. The base isolation consisted of steel roller bearings with parallel steel yield rings, to limit excessive displacements and provide wind restraint.The proposed base storey is substantially different from conventional solutions. The variation in the base-storey design was aimed at the elimination of the blind base storey or double foundation in order to increase the economy of the base-isolation system. The experimental tests showed suitable design approaches, and analytical studies to optimize them will follow.It was verified that uncoupling of buildings from the earthquake ground motion is relatively simple to achieve. Certain restraint is required to resist wind and other horizontal loads. This is usually achieved by mechanical fuses or energy absorbers. A solid state energy absorber was used in the described tests. Key words: base-isolation system for buildings, earthquake-resistant steel structures, experimental investigations, retrofit system.

Improvement of the polyurethane spring isolation device for HV post insulators and its evaluation by fragility curves

2021 ◽  
pp. 875529302098196
Author(s):  
Tansu Gökçe ◽  
Engin Orakdöğen ◽  
Ercan Yüksel
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Numerical Models ◽  
Fragility Curves ◽  
Low Cost ◽  
Steel Plates ◽  
Isolation System ◽  
Base Isolation System ◽  
Isolation Device ◽  
Seismic Base Isolation

A novel seismic base isolation system has been developed for high-voltage (HV) porcelain post insulators. The seismic isolation device consists of two steel plates, four polyurethane springs, and a steel rod, which are low-cost components compared to the post insulators. Two alternative designs of the device are experimentally and numerically assessed in this article. A simple and robust numerical model consisting of linear line elements and nonlinear springs was generated, and subsequently validated using the experimental results. Incremental dynamic analyses (IDAs) were then performed to obtain fragility curves. Ten historical earthquake profiles, scaled to intensities between 0.1 and 2.0 g, were then applied to the numerical models. The fragility curves, generated according to the latest version of IEEE-693, demonstrate that the seismic isolation devices are highly effective in diminishing the base moment of the porcelain insulator. It should be noted that relatively large displacements at the top of the pole must be accounted for by ensuring adequate slackness in the flexible conductors.

scholarly journals Seismic Performances of Conventional and LRB-Isolated Buildings Comparing to Seesaw Buildings

2020 ◽  
Vol 10 (1) ◽  
pp. 45-54
Author(s):  
Soroush Kherad ◽  
Mahmood Hosseini ◽  
Mehrtash Motamedi
Keyword(s):  
Base Isolation ◽  
Low Cost ◽  
Time History ◽  
Building Structure ◽  
Base Shear ◽  
Isolation System ◽  
Repair Work ◽  
Story Drift ◽  
Base Isolation System ◽  
Nonlinear Time History

AbstractUsing seesaw structural system equipped with energy dissipating devices has been considered as a low-cost and low-tech way for creation of earthquake-resilient buildings. In this paper by considering three groups of multi-story buildings, including conventional buildings, LRB-based isolated buildings and building with seesaw structure, equipped with a newly introduced type of structural fuses, their seismic performances have been compared through nonlinear time history analyses (NLTHA). The employed fuses in seesaw buildings are a specific type of yielding plate dampers, called Multiple Curved Yielding Plate Energy Dissipater (MCYPED), installed at the bottom of the all circumferential columns of the lowest story of the building. To show the efficiency of the proposed seesaw system in comparison with other two mentioned groups, first, by finite element modeling, verified by experimental results, the initial and secondary stiffness values as well as the yielding and ultimate strengths of the MCYPEDs have been obtained to be modeled by multi-linear plastic springs in the seesaw buildings. Then, a series of NLTHA have been performed on the three groups of buildings by using a set of selected earthquakes. The compared responses include roof displacement and acceleration, base shear, inter-story drift and finally plastic hinges (PHs) formed in the building’s structures. Results show that the proposed seesaw building equipped with MCYPEDs not only results in lower seismic demand, similar to base isolation system, but also leads to remarkable energy dissipation capacity in the building structure at base level, so that the building structure remains basically elastic, and does not need any major repair work, even after large earthquakes, contrary to the conventional building which need to be demolished after the earthquake.

scholarly journals Analytical and Experimental Overview of Fiber Reinforced Elastomeric Isolator

2021 ◽  
Vol 9 (VII) ◽  
pp. 3906-3911
Author(s):  
Afroz Qureshi
Keyword(s):  
Seismic Isolation ◽  
Seismic Waves ◽  
Base Isolation ◽  
Low Cost ◽  
Fiber Reinforced ◽  
Effective Response ◽  
Isolation System ◽  
Vertical Stiffness ◽  
Base Isolation System ◽  
Fiber Reinforced Elastomeric Isolator

There has been many researches in order to further improve the Base Isolation system by trying various combinations and alternative materials. In that fiber reinforced isometric isolators are emerged as a viable solution, because for the low cost and effective response to seismic waves as compared to the conventional isolators. Studies further shows that it provides high vertical stiffness and low horizontal stiffness, also having effective damping over the conventional one. Developing countries who doesn’t have proper seismic protection solutions have found this convenient as they are comparatively less in cost and doesn’t require complex installation. Studies also shows Un-bonded FREI has lower horizontal stiffness and considerably lower stress demand on rubber material as compared to the B-FREI and hence significantly higher seismic isolation efficiency.

Hybrid Base Isolation System with Friction Sliders and Viscous Dampers in Parallel: Comparative Dynamic Nonlinear Analysis with Traditional Fixed Base Structure

2012 ◽  
Vol 594-597 ◽  
pp. 1771-1782 ◽  
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis
Keyword(s):  
Nonlinear Analysis ◽  
Base Isolation ◽  
Protection System ◽  
Seismic Protection ◽  
Viscous Dampers ◽  
Isolation System ◽  
Fixed Base ◽  
Base Isolation System ◽  
Dynamic Nonlinear Analysis ◽  
Base Structure

In the present paper we have analyzed a multi-storey reinforced concrete (RC) building in presence of a hybrid seismic protection system for highlighting the limits of the conventional fixed base seismic design of structures. This hybrid seismic protection system is a passive structural control system that combines the Base Isolation System (BIS) and the Passive Supplemental Damping (PSD). The Viscous Dampers (VS) and Friction Sliders (FS) are the devices adopted in parallel for realizing the innovative base isolation system. The fixed base structure and the base isolated structure have been designed and verified according to the European seismic code EC8 and the European code for the design of concrete structures EC2. A three-dimensional dynamic nonlinear analysis for a base isolated structure has been performed adopting recorded accelerograms for the defined bi-directional ground motions according to the conditions imposed by EC8. The seismic isolation is a promising alternative for the earthquake resistant design of buildings and its peculiarity is that the base isolated buildings are designed such that the superstructure remains elastic and the nonlinearities are localized at the isolation level. In this paper a comparative analysis is presented between the base isolated structure, with the viscous dampers in parallel with friction sliders, and the traditional fixed-base structure.

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