scholarly journals Numerical Solutions for Nonlinear High Damping Rubber Bearing Isolators: Newmark’s Method with Netwon-Raphson Iteration Revisited

2018 ◽  
Vol 48 (1) ◽  
pp. 46-58
Author(s):  
A.A. Markou ◽  
G.D. Manolis

AbstractNumerical methods for the solution of dynamical problems in engineering go back to 1950. The most famous and widely-used time stepping algorithm was developed by Newmark in 1959. In the present study, for the first time, the Newmark algorithm is developed for the case of the trilinear hysteretic model, a model that was used to describe the shear behaviour of high damping rubber bearings. This model is calibrated against free-vibration field tests implemented on a hybrid base isolated building, namely the Solarino project in Italy, as well as against laboratory experiments. A single-degree-of-freedom system is used to describe the behaviour of a low-rise building isolated with a hybrid system comprising high damping rubber bearings and low friction sliding bearings. The behaviour of the high damping rubber bearings is simulated by the trilinear hysteretic model, while the description of the behaviour of the low friction sliding bearings is modeled by a linear Coulomb friction model. In order to prove the effectiveness of the numerical method we compare the analytically solved trilinear hysteretic model calibrated from free-vibration field tests (Solarino project) against the same model solved with the Newmark method with Netwon-Raphson iteration. Almost perfect agreement is observed between the semi-analytical solution and the fully numerical solution with Newmark’s time integration algorithm. This will allow for extension of the trilinear mechanical models to bidirectional horizontal motion, to time-varying vertical loads, to multi-degree-of-freedom-systems, as well to generalized models connected in parallel, where only numerical solutions are possible.

Seismic isolation is one of the most efficient techniques to protect structures against earthquakes. Rubber bearings are suitable for low-rise and medium-rise buildings due to its durability and easy fabrication. This paper presents the hori-zontal response of a six-storey base-isolated building using high damping rubber bearings (HDRB) under two ground motions of earthquakes as types I and II in JRA (2002) by finite element analysis. In this analysis, these bearings are mod-elled by the bilinear hysteretic model which is indicated in JRA and AASHTO. Comparison of horizontal response including base shear force and roof level acceleration between the two cases: base-isolated building and fixed-base building is carried out to evaluate the effectiveness of the use of HDRB on the protection of buildings from earthquakes. The numerical results show that the peak value of roof floor acceleration of the fixed-base building is two times higher than that of the base-isolated building, and the floor accelerations depend on the peak values of ground acceleration. In addition, the step-by-step design procedure for deter-mining the size of HDRBs used for buildings is also presented in this paper.


2012 ◽  
Vol 594-597 ◽  
pp. 1788-1799 ◽  
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis

In the present paper the dynamic nonlinear analysis for a 3D base isolated structure is illustrated. A base isolated reinforced concrete building is designed and verified according to the European seismic codes such that the superstructure remains almost completely elastic and the nonlinear elements are localized only in the base isolation system. Nonlinear hysteretic models have been adopted to reproduce the cyclic behavior of the isolators. Two different base isolation systems are considered and their performances are compared for evaluating the behaviour of a base isolated building, highly irregular in plan, in presence of a seismic excitation defined with recorded accelerograms which characterize the bi-directional ground motions. The isolation system has been realized with a combination in parallel of elastomeric bearings and sliding devices. In the first analyzed isolation system we have used the High Damping Rubber Bearings (HDRB) and in the second analyzed isolation system we have used the Lead Rubber Bearings (LRB). Finally a comparative analysis between the base isolated structure with hybrid base isolation systems and the conventional fixed base structure is detailed.


Author(s):  
Jun-Ping Pu ◽  
C. S. Tsai ◽  
Jian-Fa Huang ◽  
Bo-Jen Chen ◽  
Yao-Min Fang

In recent years, many studies on base isolation strategies and devices have been developed and applied in U. S. A., Europe, Japan, and New Zealand. The high damping rubber bearing belongs to one kind of the earthquake-proof ideas of base isolation technologies. The installation of high damping rubber bearings can lengthen the natural period of a building and simultaneously reduce the earthquake-induced energy trying to impart to the building. The objective of this paper is to investigate the base isolation effect of high damping rubber bearings. The uniaxial, biaxial, and triaxial shaking table tests were performed to study the seismic behavior of a 0.4-scale three-story isolated steel structure in the National Center for Research on Earthquake Engineering in Taiwan. The experimental and analytical results show that the nonlinear mechanical characteristics of the high damping rubber bearings can be reasonably simulated.


Sign in / Sign up

Export Citation Format

Share Document