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

Fibre-reinforced elastomeric isolator (FREI) in an un-bonded application is an improved device for seismic mitigation of low-rise buildings. It is expected to reduce the cost, weight and provide easier installation in comparison to the conventional elastomeric isolator, which consists of elastomeric layers interleaved with steel plate as reinforcement. The horizontal response of un-bonded isolator is nonlinear due to rollover deformation and the horizontal stiffness is a function of both vertical load and horizontal displacement. Most previous studies have been focused to develop the model for predicting stability of the bonded conventional elastomeric isolators with low shape factors. In the present study, predicting stability of a prototype un-bonded FREI is presented based on the dynamic response utilizing finite element (FE) analysis. A prototype isolator is investigated under the variation of vertical loads and cyclic horizontal displacement to evaluate the performance and the effect of the vertical load on the behaviour of the isolator. FE analysis result shows that the critical load capacity of the isolator is significantly higher than the design vertical load, and the effective horizontal stiffness decreases with the increase in the vertical loads. Furthermore, the horizontal response of the isolator is also conducted under the design vertical load and increasing horizontal displacement up to 2.00 t r to observe the rollout instability.

[1]  Richard Vynne Southwell,et al.  On the analysis of experimental observations in problems of elastic stability , 1932 .

[2]  Satish Nagarajaiah,et al.  Stability of Elastomeric Seismic Isolation Bearings , 1999 .

[3]  James M. Kelly,et al.  Viscoelastic Stability Model for Elastomeric Isolation Bearings , 1989 .

[4]  Robert G. Drysdale,et al.  Bonded versus unbonded strip fiber reinforced elastomeric isolators: Finite element analysis , 2011 .

[5]  G. Warn,et al.  Stability of Elastomeric and Lead-Rubber Seismic Isolation Bearings , 2012 .

[6]  Gilberto Mosqueda,et al.  Static and Dynamic Stability of Elastomeric Bearings for Seismic Protection of Structures , 2013 .

[7]  Dimitrios Konstantinidis,et al.  Mechanics of Rubber Bearings for Seismic and Vibration Isolation , 2011 .

[8]  Robert G. Drysdale,et al.  Testing and modeling of square carbon fiber‐reinforced elastomeric seismic isolators , 2008 .

[9]  Robert G. Drysdale,et al.  Simplified analysis of a low-rise building seismically isolated with stable unbonded fiber reinforced elastomeric isolators , 2009 .

[10]  Satish Nagarajaiah,et al.  Stability of Elastomeric Isolation Bearings: Experimental Study , 2002, Journal of Structural Engineering.

[11]  Robert G. Drysdale,et al.  Parametric Study on the Response of Stable Unbonded-Fiber Reinforced Elastomeric Isolators (SU-FREIs) , 2009 .

[12]  Masao Iizuka,et al.  A macroscopic model for predicting large-deformation behaviors of laminated rubber bearings , 2000 .

[13]  Xing Han,et al.  Identification of the Controlling Mechanism for Predicting Critical Loads in Elastomeric Bearings , 2013 .

[14]  John F. Stanton,et al.  Stability of Laminated Elastomeric Bearings , 1990 .

[15]  Hamid Toopchi-Nezhad,et al.  Stability of fiber-reinforced elastomeric bearings in an unbonded application , 2011 .

[16]  Dimitrios Konstantinidis,et al.  Compression of unbonded rubber layers taking into account bulk compressibility and contact slip at the supports , 2016 .

[17]  Gerhard A. Holzapfel,et al.  ON LARGE STRAIN VISCOELASTICITY: CONTINUUM FORMULATION AND FINITE ELEMENT APPLICATIONS TO ELASTOMERIC STRUCTURES , 1996 .

[18]  Satish Nagarajaiah,et al.  Dynamic Lateral Stability of Elastomeric Seismic Isolation Bearings , 2014 .