Analytical and Experimental Overview of 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.

Seismic Response Analysis of RCC Frame Building using FREI

An analysis is given for the medium-rise building with fixed base and other with base isolation device. The device hereby used for base isolation is Fiber-reinforced Elastomeric Isolator (FREI). The Fiber-reinforced Elastomeric Isolator is an isolator which uses fiber fabric material instead of steel thin plates. The main purpose of using FREI is to analyze the seismic response of medium-rise RCC frame building. As in past many research work have been carried out for low-rise building. Therefore, in this paper (G+4), (G+6), (G+8) Storey building are taken for study and analysis has been demonstrated using commercial software ETABS v17. The design of Fiber Reinforced Elastomeric Isolators is broadly based on the guidelines of ASCE 7-10. The response spectrum analysis of different storey are based on Indian Design Standard. In addition to the design of FREI, a comparison between fixed based and base isolated RCC frame building has been carried out in the form of time period, displacement, drift at various load combination. The above parameter is taken to check whether it can withstand the loads and seismic forces without any failure.

Predicting Stability of a Prototype Unbonded Fiber-Reinforced Elastomeric Isolator by Finite Element Analysis

Unbonded fiber-reinforced elastomeric isolator (U-FREI) is an improved device for seismic mitigation of low-rise buildings. The horizontal force — displacement behavior of U-FREI is nonlinear due to rollover deformation and the horizontal stiffness is a function of both vertical load and horizontal displacement. In this paper, stability of a prototype U-FREI is studied based on the dynamic response utilizing finite element (FE) analysis. Furthermore, the horizontal response of the isolator is also evaluated under the design vertical load and increasing horizontal displacement up to [Formula: see text] [Formula: see text] is the total thickness of rubber layers) to observe the rollout instability.

Effect of shear modulus on the performance of prototype un-bonded fiber reinforced elastomeric isolators

Un-bonded fiber reinforced elastomeric isolator (U-FREI) is light weight and facilitates easier installation in comparison to conventional steel reinforced elastomeric isolators (SREI), in which fiber layers are used as reinforcement to replace steel shims as are normally used in conventional isolators. Shear modulus of elastomer has significant influence on the force-displacement relationship of U-FREI. However, a few studies investigated the effect of shear modulus on the horizontal behavior of prototype U-FREI in literature. In this study, effect of shear modulus on performance of prototype U-FREIs is investigated by both experiment and finite element (FE) analysis. It is observed that reduction in horizontal stiffness of U-FREI with increasing horizontal displacement is due to both rollover deformation (or reduction in contact area of isolator with supports) and shear modulus of elastomer. Reasonable agreement is observed between the findings from experiment and FE analysis. Keywords: base isolator; prototype un-bonded fiber reinforced elastomeric isolator; rollover deformation; shear modulus; cyclic test.

Modeling and Evaluation of a Seismically Isolated Bridge Using Unbonded Fiber-Reinforced Elastomeric Isolators

An unbonded fiber-reinforced elastomeric isolator (U-FREI) is a relatively new type of elastomeric bearing that can be implemented as a seismic isolator for bridges. U-FREIs possess beneficial characteristics, including their potentially low-cost and light-weight construction. Individual U-FREIs can be rapidly produced as they can be easily cut from large sheets to the required size and shape, which is an attractive feature for accelerated bridge construction. The objectives of this paper are to introduce a noniterative analytical model to simulate the lateral response of U-FREI, and then to utilize the model to investigate the seismic response of a typical highway bridge isolated using U-FREI and compare it with a traditional non-isolated bridge. The isolated bridge demonstrated a resilient seismic behavior where all the bridge components remained elastic with no damage or residual deformation. The analytical results indicate that the seismic demand of the isolated bridge is reduced by up to 77% and 84% in terms of base shear and accelerations, respectively, as compared with the non-isolated bridge.